/*
 * %CopyrightBegin%
 *
 * Copyright Ericsson AB 1996-2022. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * %CopyrightEnd%
 */

/* 
 * I/O routines for manipulating ports.
 */

#define ERL_IO_C__

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include "sys.h"

/* must be included BEFORE global.h (since it includes erl_driver.h) */
#include "erl_sys_driver.h"
#include "erl_nif.h"

#include "erl_vm.h"
#include "global.h"
#include "erl_process.h"
#include "dist.h"
#include "big.h"
#include "erl_binary.h"
#include "erl_bits.h"
#include "erl_version.h"
#include "error.h"
#include "erl_async.h"
#define ERTS_WANT_EXTERNAL_TAGS
#include "external.h"
#include "dtrace-wrapper.h"
#include "lttng-wrapper.h"
#include "erl_map.h"
#include "erl_bif_unique.h"
#include "erl_hl_timer.h"
#include "erl_time.h"
#include "erl_io_queue.h"
#include "erl_proc_sig_queue.h"
#include "erl_global_literals.h"

extern ErlDrvEntry fd_driver_entry;
extern ErlDrvEntry vanilla_driver_entry;
extern ErlDrvEntry spawn_driver_entry;
#ifndef __WIN32__
extern ErlDrvEntry forker_driver_entry;
#endif
extern ErtsStaticDriver driver_tab[]; /* table of static drivers, only used during initialization */

erts_driver_t *driver_list; /* List of all drivers, static and dynamic. */
erts_rwmtx_t erts_driver_list_lock; /* Mutex for driver list */
static erts_tsd_key_t driver_list_lock_status_key; /*stop recursive locks when calling
							 driver init */
static erts_tsd_key_t driver_list_last_error_key;  /* Save last DDLL error on a
							  per thread basis (for BC interfaces) */

ErtsPTab erts_port erts_align_attribute(ERTS_CACHE_LINE_SIZE); /* The port table */

const ErlDrvTermData driver_term_nil = (ErlDrvTermData)NIL;

const Port erts_invalid_port = {{ERTS_INVALID_PORT}};

erts_driver_t vanilla_driver;
erts_driver_t spawn_driver;
#ifndef __WIN32__
erts_driver_t forker_driver;
#endif
erts_driver_t fd_driver;

int erts_port_synchronous_ops = 0;
int erts_port_schedule_all_ops = 0;
int erts_port_parallelism = 0;

static erts_atomic64_t bytes_in;
static erts_atomic64_t bytes_out;

static void deliver_result(Port *p, Eterm sender, Eterm pid, Eterm res);
static int init_driver(erts_driver_t *, ErlDrvEntry *, DE_Handle *);
static void terminate_port(Port *p);
static void pdl_init(void);
static int driver_failure_term(ErlDrvPort ix, Eterm term, int eof);
static void driver_monitor_lock_pdl(Port *p);
static void driver_monitor_unlock_pdl(Port *p);
#define DRV_MONITOR_LOOKUP_PORT_LOCK_PDL(Port) erts_thr_drvport2port((Port), 1)
#define DRV_MONITOR_LOCK_PDL(Port) driver_monitor_lock_pdl(Port)
#define DRV_MONITOR_UNLOCK_PDL(Port) driver_monitor_unlock_pdl(Port)

#define ERL_SMALL_IO_BIN_LIMIT (4*ERL_ONHEAP_BIN_LIMIT)
#define SMALL_WRITE_VEC  16

static ERTS_INLINE ErlPortIOQueue*
drvport2ioq(ErlDrvPort drvport)
{
    Port *prt = erts_thr_drvport2port(drvport, 0);
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return NULL;
    return &prt->ioq;
}

static ERTS_INLINE int
is_port_ioq_empty(Port *pp)
{
    int res;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(pp));
    if (!pp->port_data_lock)
	res = (erts_ioq_size(&pp->ioq) == 0);
    else {
	ErlDrvPDL pdl = pp->port_data_lock;
	erts_mtx_lock(&pdl->mtx);
	res = (erts_ioq_size(&pp->ioq) == 0);
	erts_mtx_unlock(&pdl->mtx);
    }
    return res;
}

int
erts_is_port_ioq_empty(Port *pp)
{
    return is_port_ioq_empty(pp);
}

Uint
erts_port_ioq_size(Port *pp)
{
    ErlDrvSizeT res;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(pp));
    if (!pp->port_data_lock)
	res = erts_ioq_size(&pp->ioq);
    else {
	ErlDrvPDL pdl = pp->port_data_lock;
	erts_mtx_lock(&pdl->mtx);
	res = erts_ioq_size(&pp->ioq);
	erts_mtx_unlock(&pdl->mtx);
    }
    return (Uint) res;
}

/*
 * Line buffered I/O.
 */
typedef struct line_buf_context {
    LineBuf **b;
    char *buf;
    ErlDrvSizeT left;
    ErlDrvSizeT retlen;
} LineBufContext;

#define LINEBUF_EMPTY 0
#define LINEBUF_EOL 1
#define LINEBUF_NOEOL 2
#define LINEBUF_ERROR -1

#define LINEBUF_STATE(LBC) ((*(LBC).b)->data[0])

#define LINEBUF_DATA(LBC) (((*(LBC).b)->data) + 1)
#define LINEBUF_DATALEN(LBC) ((LBC).retlen)

#define LINEBUF_INITIAL 100

#ifdef USE_VM_PROBES
#define DTRACE_FORMAT_COMMON_PID_AND_PORT(PID, PORT)         \
    DTRACE_CHARBUF(process_str, DTRACE_TERM_BUF_SIZE);       \
    DTRACE_CHARBUF(port_str, DTRACE_TERM_BUF_SIZE);          \
                                                             \
    dtrace_pid_str((PID), process_str);                      \
    dtrace_port_str((PORT), port_str);
#define DTRACE_FORMAT_COMMON_PROC_AND_PORT(PID, PORT)        \
    DTRACE_CHARBUF(process_str, DTRACE_TERM_BUF_SIZE);       \
    DTRACE_CHARBUF(port_str, DTRACE_TERM_BUF_SIZE);          \
                                                             \
    dtrace_proc_str((PID), process_str);                     \
    dtrace_port_str((PORT), port_str);

void
dtrace_drvport_str(ErlDrvPort drvport, char *port_buf)
{
    Port *port = erts_drvport2port(drvport);

    if (port != ERTS_INVALID_ERL_DRV_PORT)
	erts_snprintf(port_buf, DTRACE_TERM_BUF_SIZE, "#Port<%lu.%b64u>",
		      port_channel_no(port->common.id),
		      port_number(port->common.id));
    else
	erts_snprintf(port_buf, DTRACE_TERM_BUF_SIZE, "#Port<%lu.INVALID>",
		      port_channel_no(port->common.id));
}

#endif

static ERTS_INLINE void
kill_port(Port *pp)
{
    ERTS_LC_ASSERT(erts_lc_is_port_locked(pp));
    ERTS_TRACER_CLEAR(&ERTS_TRACER(pp));
    erts_ptab_delete_element(&erts_port, &pp->common); /* Time of death */
    erts_port_task_free_port(pp);
    /* In non-smp case the port structure may have been deallocated now */
}


#ifdef ERTS_ENABLE_LOCK_CHECK
int
erts_lc_is_port_locked(Port *prt)
{
    if (!prt)
	return 0;
    ERTS_LC_ASSERT(prt->lock);
    return erts_lc_mtx_is_locked(prt->lock);
}
#endif


static void initq(Port* prt);

#if defined(ERTS_ENABLE_LOCK_CHECK) || defined(ERTS_ENABLE_LOCK_COUNT)
#define ERTS_PORT_INIT_INSTR_NEED_ID 1
#else
#define ERTS_PORT_INIT_INSTR_NEED_ID 0
#endif

static ERTS_INLINE void port_init_instr(Port *prt
#if ERTS_PORT_INIT_INSTR_NEED_ID
				   , Eterm id
#endif
    )
{
#if !ERTS_PORT_INIT_INSTR_NEED_ID
    Eterm id = NIL; /* Not used */
#endif

    /*
     * Stuff that need to be initialized with the port id
     * in the instrumented case, but not in the normal case.
     */
    ASSERT(prt->drv_ptr && prt->lock);
    if (!prt->drv_ptr->lock) {
        erts_mtx_init_locked(prt->lock, "port_lock", id, ERTS_LOCK_FLAGS_CATEGORY_IO);
    }
    erts_port_task_init_sched(&prt->sched, id);
}

#if !ERTS_PORT_INIT_INSTR_NEED_ID
static ERTS_INLINE void port_init_instr_abort(Port *prt)
{
    ASSERT(prt->drv_ptr && prt->lock);
    if (!prt->drv_ptr->lock) {
	erts_mtx_unlock(prt->lock);
	erts_mtx_destroy(prt->lock);
    }
    erts_port_task_fini_sched(&prt->sched);
}
#endif

static void insert_port_struct(void *vprt, Eterm data)
{
    Port *prt = (Port *) vprt;
    Eterm id = make_internal_port(data);
#if ERTS_PORT_INIT_INSTR_NEED_ID
    /*
     * This cannot be done earlier in the instrumented
     * case since we don't now 'id' until now.
     */
    port_init_instr(prt, id);
#endif
    prt->common.id = id;
    erts_atomic32_init_relb(&prt->state, ERTS_PORT_SFLG_INITIALIZING);
}

#define ERTS_CREATE_PORT_FLAG_PARALLELISM		(1 << 0)

static Port *create_port(char *name,
			 erts_driver_t *driver,
			 erts_mtx_t *driver_lock,
			 int create_flags,
			 Eterm pid,
			 int *enop)
{
    ErtsPortTaskBusyPortQ *busy_port_queue;
    Port *prt;
    char *p;
    size_t port_size, busy_port_queue_size, size;
    erts_aint32_t state = ERTS_PORT_SFLG_CONNECTED;
    erts_aint32_t x_pts_flgs = 0;

    if (!driver_lock) {
	/* Align size for mutex following port struct */
	port_size = size = ERTS_ALC_DATA_ALIGN_SIZE(sizeof(Port));
	size += sizeof(erts_mtx_t);
    }
    else
	port_size = size = ERTS_ALC_DATA_ALIGN_SIZE(sizeof(Port));

#ifdef DEBUG
    /* Make sure the debug flags survives until port is freed */
    state |= ERTS_PORT_SFLG_PORT_DEBUG;
#endif


    busy_port_queue_size
	= ((driver->flags & ERL_DRV_FLAG_NO_BUSY_MSGQ)
	   ? 0
	   : ERTS_ALC_DATA_ALIGN_SIZE(sizeof(ErtsPortTaskBusyPortQ)));
    size += busy_port_queue_size;

    size += sys_strlen(name) + 1;

    p = erts_alloc_fnf(ERTS_ALC_T_PORT, size);
    if (!p) {
	if (enop)
	    *enop = ENOMEM;
	return NULL;
    }

    prt = (Port *) p;
    p += port_size;

    if (!busy_port_queue_size)
	busy_port_queue = NULL;
    else {
	busy_port_queue = (ErtsPortTaskBusyPortQ *) p;
	p += busy_port_queue_size;
    }

    if (driver_lock) {
	prt->lock = driver_lock;
	erts_mtx_lock(driver_lock);
    }
    else {
	prt->lock = (erts_mtx_t *) p;
	p += sizeof(erts_mtx_t);
	state |= ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK;
    }

    {
        ErtsRunQueue *runq;
        ErtsSchedulerData *esdp = erts_get_scheduler_data();
        if (esdp)
            runq = erts_get_runq_current(esdp);
        else
            runq = ERTS_RUNQ_IX(0);
        erts_init_runq_port(prt, runq);
    }

    prt->xports = NULL;
    
    erts_port_task_pre_init_sched(&prt->sched, busy_port_queue);

    prt->name = p;
    sys_strcpy(p, name);
    prt->drv_ptr = driver;
    ERTS_P_LINKS(prt) = NULL;
    ERTS_P_MONITORS(prt) = NULL;
    ERTS_P_LT_MONITORS(prt) = NULL;
    prt->linebuf = NULL;
    prt->suspended = NULL;
    erts_init_port_data(prt);
    prt->port_data_lock = NULL;
    prt->control_flags = 0;
    prt->bytes_in = 0;
    prt->bytes_out = 0;
    ERTS_PORT_INIT_CONNECTED(prt, pid);
    prt->common.u.alive.reg = NULL;
    ERTS_PTMR_INIT(prt);
    erts_port_task_handle_init(&prt->timeout_task);
    erts_atomic_init_nob(&prt->psd, (erts_aint_t) NULL);
    prt->async_open_port = NULL;
    prt->drv_data = (SWord) 0;
    prt->os_pid = -1;

    /* Set default tracing */
    erts_get_default_port_tracing(&ERTS_TRACE_FLAGS(prt), &ERTS_TRACER(prt));

    ERTS_CT_ASSERT(offsetof(Port,common) == 0);

#if !ERTS_PORT_INIT_INSTR_NEED_ID
    /*
     * When 'id' isn't needed (the normal case), it is better to
     * do the initialization here avoiding unnecessary contention
     * on table...
     */
    port_init_instr(prt);
#endif

    if (!erts_ptab_new_element(&erts_port,
			       &prt->common,
			       (void *) prt,
			       insert_port_struct)) {

#if !ERTS_PORT_INIT_INSTR_NEED_ID
	port_init_instr_abort(prt);
#endif
	if (driver_lock)
	    erts_mtx_unlock(driver_lock);
	if (enop)
	    *enop = 0;
	erts_free(ERTS_ALC_T_PORT, prt);
	return NULL;
    }

    ASSERT(prt == (Port *) (erts_ptab_pix2intptr_nob(
				&erts_port,
				internal_port_index(prt->common.id))));

    initq(prt);

    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));

    if (erts_port_schedule_all_ops)
	x_pts_flgs |= ERTS_PTS_FLG_FORCE_SCHED;

    if (create_flags & ERTS_CREATE_PORT_FLAG_PARALLELISM)
	x_pts_flgs |= ERTS_PTS_FLG_PARALLELISM;

    if (x_pts_flgs)
	erts_atomic32_read_bor_nob(&prt->sched.flags, x_pts_flgs);

    erts_atomic32_set_relb(&prt->state, state);
    return prt;
}


void
erts_port_free(Port *prt)
{
    erts_aint32_t state = erts_atomic32_read_nob(&prt->state);
    ERTS_LC_ASSERT(state & (ERTS_PORT_SFLG_INITIALIZING
			    | ERTS_PORT_SFLG_FREE));
    ASSERT(state & ERTS_PORT_SFLG_PORT_DEBUG);

    ERTS_LC_ASSERT(erts_atomic_read_nob(&prt->common.refc.atmc) == 0);

    erts_port_task_fini_sched(&prt->sched);

    if (prt->async_open_port) {
        erts_free(ERTS_ALC_T_PRTSD, prt->async_open_port);
        prt->async_open_port = NULL;
    }

    ASSERT(prt->lock);
    if (state & ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK)
	erts_mtx_destroy(prt->lock);

    /*
     * We cannot dereference a driver using driver
     * locking until here in smp case. Otherwise,
     * the driver lock may still be in use by others.
     *
     * In the non-smp case we cannot do it here since
     * this function may be called by non-scheduler
     * threads. This is done in erts_port_cleanup()
     * in the non-smp case.
     */
    if (prt->drv_ptr->handle)
	erts_ddll_dereference_driver(prt->drv_ptr->handle);
    erts_free(ERTS_ALC_T_PORT, prt);
}

/*
** Initialize v_start to point to the small fixed vector.
** Once (reallocated) we never reset the pointer to the small vector
** This is a possible optimisation.
*/
static void initq(Port* prt)
{
    ERTS_LC_ASSERT(!prt->port_data_lock);
    erts_ioq_init(&prt->ioq, ERTS_ALC_T_IOQ, 1);
}

static void stopq(Port* prt)
{

    if (prt->port_data_lock)
	driver_pdl_lock(prt->port_data_lock);

    erts_ioq_clear(&prt->ioq);

    if (prt->port_data_lock) {
	driver_pdl_unlock(prt->port_data_lock);
	driver_pdl_dec_refc(prt->port_data_lock);
    }
}

int
erts_save_suspend_process_on_port(Port *prt, Process *process)
{
    int saved;
    erts_aint32_t flags;
    erts_port_task_sched_lock(&prt->sched);
    flags = erts_atomic32_read_nob(&prt->sched.flags);
    saved = (flags & ERTS_PTS_FLGS_BUSY) && !(flags & ERTS_PTS_FLG_EXIT);
    if (saved)
	erts_proclist_store_last(&prt->suspended, erts_proclist_create(process));
    erts_port_task_sched_unlock(&prt->sched);
    return saved;
}

/*
   Opens a driver.
   Returns the non-negative port number, if successful.
   If there is an error, -1 or -2 or -3 is returned. -2 means that
   there is valid error information in *error_number_ptr.
   Returning -3 means that an error in the given options was detected
   (*error_number_ptr must contain either BADARG or SYSTEM_LIMIT).
   The driver start function must obey the same conventions.
*/
Port *
erts_open_driver(erts_driver_t* driver,	/* Pointer to driver. */
		 Eterm pid,		/* Current process. */
		 char* name,		/* Driver name. */
		 SysDriverOpts* opts,	/* Options. */
		 int *error_type_ptr,	/* error type */
		 int *error_number_ptr)	/* errno in case of error type -2 */
{

#undef ERTS_OPEN_DRIVER_RET
#define ERTS_OPEN_DRIVER_RET(Prt, EType, ENo)	\
    do {					\
	if (error_type_ptr)			\
	    *error_type_ptr = (EType);		\
	if (error_number_ptr)			\
	    *error_number_ptr = (ENo);		\
	return (Prt);				\
    } while (0)

    ErlDrvData drv_data = 0;
    Port *port;
    int error_type, error_number;
    int port_errno = 0;
    erts_mtx_t *driver_lock = NULL;
    int cprt_flgs = 0;

    ERTS_CHK_NO_PROC_LOCKS;

    erts_rwmtx_rlock(&erts_driver_list_lock);
    if (!driver) {
	for (driver = driver_list; driver; driver = driver->next) {
	    if (sys_strcmp(driver->name, name) == 0)
		break;
	}
	if (!driver) { 
	    erts_rwmtx_runlock(&erts_driver_list_lock);
	    ERTS_OPEN_DRIVER_RET(NULL, -3, BADARG);
	}
    }
    if (driver == &spawn_driver) {
	char *p;
	erts_driver_t *d;

	/*
	 * Dig out the name of the driver or port program.
	 */

	if (!(opts->spawn_type & ERTS_SPAWN_EXECUTABLE)) {
	    /* No spawn driver default */
	    driver = NULL;
	} else {
#ifdef __IOS__ 
	    erts_rwmtx_runlock(&erts_driver_list_lock);
	    ERTS_OPEN_DRIVER_RET(NULL, -3, BADARG);	   
#endif
    }


	if (opts->spawn_type != ERTS_SPAWN_EXECUTABLE) {
	    p = name;
	    while(*p != '\0' && *p != ' ')
		p++;
	    if (*p == '\0')
		p = NULL;
	    else
		*p = '\0';

	    /*
	     * Search for a driver having this name.  Defaults to spawn_driver
	     * if not found.
	     */
	    
	    for (d = driver_list; d; d = d->next) {
		if (sys_strcmp(d->name, name) == 0 && 
		    erts_ddll_driver_ok(d->handle)) {
		    driver = d;
		    break;
		}
	    }
	    if (p != NULL)
		*p = ' ';
	}
    }

    if (driver == NULL || (driver != &spawn_driver && opts->exit_status)) {
	erts_rwmtx_runlock(&erts_driver_list_lock);
	ERTS_OPEN_DRIVER_RET(NULL, -3, BADARG);
    }

    if (opts->port_watermarks_set && driver != &spawn_driver
        && driver != &fd_driver && driver != &vanilla_driver) {
	erts_rwmtx_runlock(&erts_driver_list_lock);
	ERTS_OPEN_DRIVER_RET(NULL, -3, BADARG);
    }

    if (opts->msgq_watermarks_set
        && (driver->flags & ERL_DRV_FLAG_NO_BUSY_MSGQ)
        && opts->high_msgq_watermark != ERL_DRV_BUSY_MSGQ_DISABLED) {
	erts_rwmtx_runlock(&erts_driver_list_lock);
	ERTS_OPEN_DRIVER_RET(NULL, -3, BADARG);
    }
    
    driver_lock = driver->lock;

    if (driver->handle != NULL) {
	erts_ddll_increment_port_count(driver->handle);
	erts_ddll_reference_driver(driver->handle);
    }
    erts_rwmtx_runlock(&erts_driver_list_lock);

    /*
     * We'll set up the port before calling the start function,
     * to allow message sending and setting timers in the start function.
     */

    if (opts->parallelism)
	cprt_flgs |= ERTS_CREATE_PORT_FLAG_PARALLELISM;

    port = create_port(name, driver, driver_lock, cprt_flgs, pid, &port_errno);
    if (!port) {
	if (driver->handle) {
	    erts_rwmtx_rlock(&erts_driver_list_lock);
	    erts_ddll_decrement_port_count(driver->handle);
	    erts_rwmtx_runlock(&erts_driver_list_lock);
	    erts_ddll_dereference_driver(driver->handle);
	}
	if (port_errno)
	    ERTS_OPEN_DRIVER_RET(NULL, -2, port_errno);
	else
	    ERTS_OPEN_DRIVER_RET(NULL, -3, SYSTEM_LIMIT);
    }
    
    if (IS_TRACED_FL(port, F_TRACE_PORTS)) {
	trace_port_open(port,
			pid,
			erts_atom_put((byte *) port->name,
				      sys_strlen(port->name),
				      ERTS_ATOM_ENC_LATIN1,
				      1));
    }

    if (opts->msgq_watermarks_set)
        erl_drv_busy_msgq_limits(ERTS_Port2ErlDrvPort(port),
                                 &opts->low_msgq_watermark,
                                 &opts->high_msgq_watermark);

    error_number = error_type = 0;
    if (driver->start) {
        ERTS_MSACC_PUSH_STATE_M();
	if (IS_TRACED_FL(port, F_TRACE_SCHED_PORTS)) {
	    trace_sched_ports_where(port, am_in, am_open);
	}
	port->caller = pid;
#ifdef USE_VM_PROBES
        if (DTRACE_ENABLED(driver_start)) {
            DTRACE_FORMAT_COMMON_PID_AND_PORT(pid, port)
            DTRACE3(driver_start, process_str, driver->name, port_str);
        }
#endif

	ERTS_MSACC_SET_STATE_CACHED_M(ERTS_MSACC_STATE_PORT);

#ifdef USE_LTTNG_VM_TRACEPOINTS
        if (LTTNG_ENABLED(driver_start)) {
            lttng_decl_portbuf(port_str);
            lttng_decl_procbuf(proc_str);
            lttng_pid_to_str(pid, proc_str);
            lttng_port_to_str(port, port_str);
            LTTNG3(driver_start, proc_str, driver->name, port_str);
        }
#endif

	drv_data = (*driver->start)(ERTS_Port2ErlDrvPort(port), name, opts);
	if (((SWord) drv_data) == -1)
	    error_type = -1;
	else if (((SWord) drv_data) == -2) {
	    /*
	     * We need to save errno quickly after the
	     * call to the 'start' callback before
	     * something else modify it.
	     */
	    error_type = -2;
	    error_number = errno;
	}
	else if (((SWord) drv_data) == -3) {
	    error_type = -3;
	    error_number = BADARG;
	}

	ERTS_MSACC_POP_STATE_M();
	port->caller = NIL;
	if (IS_TRACED_FL(port, F_TRACE_SCHED_PORTS)) {
	    trace_sched_ports_where(port, am_out, am_open);
	}
	if (port->xports)
	    erts_port_handle_xports(port);
	ASSERT(!port->xports);
    }

    if (error_type) {
	/*
	 * Must clean up the port.
	 */
	erts_cancel_port_timer(port);
	stopq(port);
	if (port->linebuf != NULL) {
	    erts_free(ERTS_ALC_T_LINEBUF,
		      (void *) port->linebuf);
	    port->linebuf = NULL;
	}
	if (driver->handle != NULL) {
	    erts_rwmtx_rlock(&erts_driver_list_lock);
	    erts_ddll_decrement_port_count(driver->handle);
	    erts_rwmtx_runlock(&erts_driver_list_lock);
	}
	kill_port(port);
	erts_port_release(port);
	ERTS_OPEN_DRIVER_RET(NULL, error_type, error_number);
    }
    port->drv_data = (UWord) drv_data;
    ERTS_OPEN_DRIVER_RET(port, 0, 0);

#undef ERTS_OPEN_DRIVER_RET
}


struct ErtsXPortsList_ {
    ErtsXPortsList *next;
    Port *port;
};

ERTS_SCHED_PREF_QUICK_ALLOC_IMPL(xports_list, ErtsXPortsList, 50, ERTS_ALC_T_XPORTS_LIST)


/*
 * Driver function to create new instances of a driver
 * Historical reason: to be used with inet_drv for creating
 * accept sockets inorder to avoid a global table.
 */
ErlDrvPort
driver_create_port(ErlDrvPort creator_port_ix, /* Creating port */
		   ErlDrvTermData pid,    /* Owner/Caller */
		   char* name,            /* Driver name */
		   ErlDrvData drv_data)   /* Driver data */
{
    int cprt_flgs = 0;
    Port *creator_port;
    Port* port;
    erts_driver_t *driver;
    erts_mtx_t *driver_lock = NULL;
    ErtsLink *port_lnk, *proc_lnk;

    ERTS_CHK_NO_PROC_LOCKS;

    /* Need to be called from a scheduler thread */
    if (!erts_get_scheduler_id())
	return ERTS_INVALID_ERL_DRV_PORT;

    creator_port = erts_drvport2port(creator_port_ix);
    if (creator_port == ERTS_INVALID_ERL_DRV_PORT)
	return ERTS_INVALID_ERL_DRV_PORT;

    ERTS_LC_ASSERT(erts_lc_is_port_locked(creator_port));

    driver = creator_port->drv_ptr;
    erts_rwmtx_rlock(&erts_driver_list_lock);
    if (!erts_ddll_driver_ok(driver->handle)) {
	erts_rwmtx_runlock(&erts_driver_list_lock);
        return ERTS_INVALID_ERL_DRV_PORT;
    }

    if (driver->handle != NULL) {
	erts_ddll_increment_port_count(driver->handle);
	erts_ddll_reference_referenced_driver(driver->handle);
    }

    driver_lock = driver->lock;

    erts_rwmtx_runlock(&erts_driver_list_lock);

    /* Inherit parallelism flag from parent */
    if (ERTS_PTS_FLG_PARALLELISM &
	erts_atomic32_read_nob(&creator_port->sched.flags))
	cprt_flgs |= ERTS_CREATE_PORT_FLAG_PARALLELISM;
    port = create_port(name, driver, driver_lock, cprt_flgs, pid, NULL);
    if (!port) {
	if (driver->handle) {
	    erts_rwmtx_rlock(&erts_driver_list_lock);
	    erts_ddll_decrement_port_count(driver->handle);
	    erts_rwmtx_runlock(&erts_driver_list_lock);
	    erts_ddll_dereference_driver(driver->handle);
	}
	return ERTS_INVALID_ERL_DRV_PORT;
    }
    ERTS_LC_ASSERT(erts_lc_is_port_locked(port));

    port_lnk = erts_link_internal_create(ERTS_LNK_TYPE_PORT, pid);
    erts_link_tree_insert(&ERTS_P_LINKS(port), port_lnk);
    proc_lnk = erts_link_internal_create(ERTS_LNK_TYPE_PORT, port->common.id);
    if (!erts_proc_sig_send_link(&port->common, port->common.id,
                                 pid, proc_lnk)) {
        erts_link_tree_delete(&ERTS_P_LINKS(port), port_lnk);
        erts_link_internal_release(proc_lnk);
        erts_link_internal_release(port_lnk);
	if (driver->handle) {
	    erts_rwmtx_rlock(&erts_driver_list_lock);
	    erts_ddll_decrement_port_count(driver->handle);
	    erts_rwmtx_runlock(&erts_driver_list_lock);
	}
	kill_port(port);
	erts_port_release(port);
	return ERTS_INVALID_ERL_DRV_PORT;
    }

    if (!driver_lock) {
	ErtsXPortsList *xplp = xports_list_alloc();
	xplp->port = port;
	xplp->next = creator_port->xports;
	creator_port->xports = xplp;
    }

    port->drv_data = (UWord) drv_data;

    return ERTS_Port2ErlDrvPort(port);
}

int erts_port_handle_xports(Port *prt)
{
    int reds = 0;
    ErtsXPortsList *xplp;

    ASSERT(prt);
    xplp = prt->xports;
    ASSERT(xplp);
    while (xplp) {
	Port *rprt = xplp->port;
	ErtsXPortsList *free_xplp;
	erts_aint32_t state;
	if (rprt->xports)
	    reds += erts_port_handle_xports(rprt);
	state = erts_atomic32_read_nob(&rprt->state);
	if ((state & ERTS_PORT_SFLG_CLOSING) && erts_is_port_ioq_empty(rprt)) {
	    terminate_port(rprt);
	    reds += ERTS_PORT_REDS_TERMINATE;
	}
	erts_port_release(rprt);
	free_xplp = xplp;
	xplp = xplp->next;
	xports_list_free(free_xplp);
	reds++;
    }
    prt->xports = NULL;
    return reds;
}

typedef enum {
    ERTS_TRY_IMM_DRV_CALL_OK,
    ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK,
    ERTS_TRY_IMM_DRV_CALL_INVALID_PORT,
    ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS
} ErtsTryImmDrvCallResult;

typedef struct {
    Process *c_p; /* Currently executing process (unlocked) */
    Port *port; /* Port to operate on */
    Eterm port_op; /* port operation as an atom */
    erts_aint32_t state; /* in: invalid state; out: read state (if read) */
    erts_aint32_t sched_flags; /* in: invalid flags; out: read flags (if read) */
    int async; /* Asynchronous operation */
    int pre_chk_sched_flags; /* Check sched flags before lock? */
    int reds_left_in;
} ErtsTryImmDrvCallState;

#define ERTS_INIT_TRY_IMM_DRV_CALL_STATE(C_P, PRT, SFLGS, PTS_FLGS, A, PRT_OP) \
    {(C_P), (PRT), (PRT_OP), (SFLGS), (PTS_FLGS), (A), 1, 0}

/*
 * Try doing an immediate driver callback call from a process. If
 * this fail, the operation should be scheduled in the normal case...
 * Returns: ok to do the call, or error (lock busy, does not exist, etc)
 */
static ERTS_INLINE ErtsTryImmDrvCallResult
try_imm_drv_call(ErtsTryImmDrvCallState *sp)
{
    unsigned int prof_runnable_ports;
    ErtsTryImmDrvCallResult res;
    int reds_left_in;
    erts_aint32_t act, exp, invalid_state, invalid_sched_flags;
    Port *prt = sp->port;
    Process *c_p = sp->c_p;

    ASSERT(is_atom(sp->port_op));

    invalid_sched_flags = ERTS_PTS_FLGS_FORCE_SCHEDULE_OP;
    invalid_sched_flags |= sp->sched_flags;
    if (sp->async)
	invalid_sched_flags |= ERTS_PTS_FLG_PARALLELISM;

    if (sp->pre_chk_sched_flags) {
	sp->sched_flags = erts_atomic32_read_nob(&prt->sched.flags);
	if (sp->sched_flags & invalid_sched_flags)
	    return ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS;
    }

    if (erts_port_trylock(prt) == EBUSY)
	return ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK;

    invalid_state = sp->state;
    sp->state = erts_atomic32_read_nob(&prt->state);
    if (sp->state & invalid_state) {
	res = ERTS_TRY_IMM_DRV_CALL_INVALID_PORT;
	goto locked_fail;
    }

    prof_runnable_ports = erts_system_profile_flags.runnable_ports;
    if (prof_runnable_ports)
	erts_port_task_sched_lock(&prt->sched);

    act = erts_atomic32_read_nob(&prt->sched.flags);

    do {
	erts_aint32_t new;
	
	if (act & invalid_sched_flags) {
	    res = ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS;
	    sp->sched_flags = act;
	    goto locked_fail;
	}
	exp = act;
	new = act | ERTS_PTS_FLG_EXEC_IMM;
	act = erts_atomic32_cmpxchg_mb(&prt->sched.flags, new, exp);
    } while (act != exp);
    
    sp->sched_flags = act;

    if (!c_p)
	reds_left_in = CONTEXT_REDS/10;
    else {
	if (IS_TRACED_FL(c_p, F_TRACE_SCHED_PROCS))
	    trace_sched(c_p, ERTS_PROC_LOCK_MAIN, am_out);
	/*
	 * No status lock held while sending runnable
	 * proc trace messages. It is however not needed
	 * in this case, since only this thread can send
	 * such messages for this process until the process
	 * has been scheduled out.
	 */
	if (erts_system_profile_flags.runnable_procs
	    && erts_system_profile_flags.exclusive)
	    profile_runnable_proc(c_p, am_inactive);

	reds_left_in = ERTS_BIF_REDS_LEFT(c_p);
	erts_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);

        ASSERT((c_p->scheduler_data)->current_port == NULL);
        (c_p->scheduler_data)->current_port = prt;
    }

    ASSERT(0 <= reds_left_in && reds_left_in <= CONTEXT_REDS);
    sp->reds_left_in = reds_left_in;
    prt->reds = CONTEXT_REDS - reds_left_in;

    ERTS_CHK_NO_PROC_LOCKS;

    if (prof_runnable_ports | IS_TRACED_FL(prt, F_TRACE_SCHED_PORTS)) {
	if (prof_runnable_ports && !(act & (ERTS_PTS_FLG_IN_RUNQ|ERTS_PTS_FLG_EXEC)))
	    profile_runnable_port(prt, am_active);
	if (IS_TRACED_FL(prt, F_TRACE_SCHED_PORTS))
	    trace_sched_ports_where(prt, am_in, sp->port_op);
	if (prof_runnable_ports)
	    erts_port_task_sched_unlock(&prt->sched);
    }

    return ERTS_TRY_IMM_DRV_CALL_OK;

locked_fail:
    erts_port_release(prt);
    return res;
}

static ERTS_INLINE void
finalize_imm_drv_call(ErtsTryImmDrvCallState *sp)
{
    int reds;
    Port *prt = sp->port;
    Process *c_p = sp->c_p;
    erts_aint32_t act;
    unsigned int prof_runnable_ports;

    reds = prt->reds;
    reds += erts_port_driver_callback_epilogue(prt, NULL);

    prof_runnable_ports = erts_system_profile_flags.runnable_ports;
    if (prof_runnable_ports)
	erts_port_task_sched_lock(&prt->sched);

    act = erts_atomic32_read_band_mb(&prt->sched.flags,
					 ~ERTS_PTS_FLG_EXEC_IMM);
    ERTS_LC_ASSERT(act & ERTS_PTS_FLG_EXEC_IMM);

    if (prof_runnable_ports | IS_TRACED_FL(prt, F_TRACE_SCHED_PORTS)) {
	if (IS_TRACED_FL(prt, F_TRACE_SCHED_PORTS))
	    trace_sched_ports_where(prt, am_out, sp->port_op);
	if (prof_runnable_ports) {
	    if (!(act & (ERTS_PTS_FLG_IN_RUNQ|ERTS_PTS_FLG_EXEC)))
		profile_runnable_port(prt, am_inactive);
	    erts_port_task_sched_unlock(&prt->sched);
	}
    }

    erts_port_release(prt);

    if (c_p) {
        ASSERT((c_p->scheduler_data)->current_port == prt);
        (c_p->scheduler_data)->current_port = NULL;

	erts_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);

	if (reds != (CONTEXT_REDS - sp->reds_left_in)) {
	    int bump_reds = reds - (CONTEXT_REDS - sp->reds_left_in);
	    ASSERT(bump_reds > 0);
	    BUMP_REDS(c_p, bump_reds);
	}

	if (IS_TRACED_FL(c_p, F_TRACE_SCHED_PROCS))
	    trace_sched(c_p, ERTS_PROC_LOCK_MAIN, am_in);
	/*
	 * No status lock held while sending runnable
	 * proc trace messages. It is however not needed
	 * in this case, since only this thread can send
	 * such messages for this process until the process
	 * has been scheduled out.
	 */
	if (erts_system_profile_flags.runnable_procs
	    && erts_system_profile_flags.exclusive)
	    profile_runnable_proc(c_p, am_active);
    }
}

/*
 * force_imm_drv_call()/finalize_force_imm_drv_call() should *only*
 * be used while crash dumping...
 */
static ErtsTryImmDrvCallResult
force_imm_drv_call(ErtsTryImmDrvCallState *sp)
{
    erts_aint32_t invalid_state;
    Port *prt = sp->port;

    ASSERT(ERTS_IS_CRASH_DUMPING);
    ASSERT(is_atom(sp->port_op));

    invalid_state = sp->state;
    sp->state = erts_atomic32_read_nob(&prt->state);
    if (sp->state & invalid_state)
	return ERTS_TRY_IMM_DRV_CALL_INVALID_PORT;

    return ERTS_TRY_IMM_DRV_CALL_OK;
}

static void
finalize_force_imm_drv_call(ErtsTryImmDrvCallState *sp)
{
}

#define ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE (ERTS_REF_THING_SIZE + 3)

static ERTS_INLINE void
queue_port_sched_op_reply(Process *rp,
			  ErtsProcLocks rp_locks,
                          ErtsHeapFactory* factory,
			  Uint32 *ref_num,
			  Eterm msg,
			  Port* prt)
{
    Eterm* hp = erts_produce_heap(factory, ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE, 0);
    Eterm ref;

    ref= make_internal_ref(hp);
    write_ref_thing(hp, ref_num[0], ref_num[1], ref_num[2]);
    hp += ERTS_REF_THING_SIZE;

    msg = TUPLE2(hp, ref, msg);

    erts_factory_trim_and_close(factory, &msg, 1);

    erts_queue_message(rp, rp_locks, factory->message, msg,
		       prt ? prt->common.id : am_undefined);
}

static void
port_sched_op_reply(Eterm to, Uint32 *ref_num, Eterm msg, Port* prt)
{
    Process *rp = erts_proc_lookup_raw(to);
    if (rp) {
        ErtsHeapFactory factory;
	Eterm msg_copy;
	Uint hsz, msg_sz;
	ErtsProcLocks rp_locks = 0;

	hsz = ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE;
	if (is_immed(msg))
	    msg_sz = 0;
	else {
	    msg_sz = size_object(msg);
	    hsz += msg_sz;
	}

	(void) erts_factory_message_create(&factory, rp,
					   &rp_locks, hsz);
	msg_copy = (is_immed(msg)
		    ? msg
		    : copy_struct(msg, msg_sz,
				  &factory.hp,
				  factory.off_heap));

	queue_port_sched_op_reply(rp,
				  rp_locks,
                                  &factory,
				  ref_num,
				  msg_copy,
				  prt);

	if (rp_locks)
	    erts_proc_unlock(rp, rp_locks);
    }
}


static ErtsPortOpResult
erts_schedule_proc2port_signal(Process *c_p,
			       Port *prt,
			       Eterm caller,
			       Eterm *refp,
			       ErtsProc2PortSigData *sigdp,
			       int task_flags,
			       ErtsPortTaskHandle *pthp,
			       ErtsProc2PortSigCallback callback)
{
    if (!refp) {
	if (c_p)
	    erts_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
    }
    else {
	ASSERT(c_p);
	sigdp->flags |= ERTS_P2P_SIG_DATA_FLG_REPLY;
	erts_make_ref_in_array(sigdp->ref);
	*refp = erts_proc_store_ref(c_p, sigdp->ref);

	/*
	 * Caller needs to wait for a message containing
	 * the ref that we just created. No such message
	 * can exist in callers message queue at this time.
	 * We therefore move the save pointer of the
	 * callers message queue to the end of the queue.
	 *
	 * NOTE: It is of vital importance that the caller
	 *       immediately do a receive unconditionally
	 *       waiting for the message with the reference;
	 *       otherwise, next receive will *not* work
	 *       as expected!
	 */
        erts_msgq_set_save_end(c_p);

        erts_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
    }


    sigdp->caller = caller;

    /*
     * Schedule port execution of the callback. Note that
     * the callback will be called even if we aren't
     * able to lookup the port or if its state is invalid.
     * Callback will in that case be called in "abort mode".
     * We therefore always return ERTS_PORT_OP_SCHEDULED.
     */
    (void) erts_port_task_schedule(prt->common.id,
                                   pthp,
                                   ERTS_PORT_TASK_PROC_SIG,
                                   sigdp,
                                   callback,
                                   task_flags);

    if (c_p)
	erts_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);

    return ERTS_PORT_OP_SCHEDULED;
}

static int
erts_schedule_port2port_signal(Eterm port_num, ErtsProc2PortSigData *sigdp,
                               int task_flags,
                               ErtsProc2PortSigCallback callback)
{
    sigdp->caller = ERTS_INVALID_PID;

    return erts_port_task_schedule(port_num,
                                   NULL,
                                   ERTS_PORT_TASK_PROC_SIG,
                                   sigdp,
                                   callback,
                                   task_flags);
}

static ERTS_INLINE void
send_badsig(Port *prt) {
    Eterm connected = ERTS_PORT_GET_CONNECTED(prt);
    ERTS_CHK_NO_PROC_LOCKS;
    ERTS_LC_ASSERT(erts_get_scheduler_id());
    ASSERT(is_internal_pid(connected));
    erts_proc_sig_send_exit(&prt->common, prt->common.id, connected,
                            am_badsig, NIL, 0);
} /* send_badsig */

static void
badsig_received(int bang_op, Port *prt,
		erts_aint32_t state,
		int bad_output_value) {
    /*
     * if (bang_op)
     *   we are part of a "Prt ! Something" operation
     * else
     *   we are part of a call to a port BIF
     * behave accordingly...
     */
    if (!(state & ERTS_PORT_SFLGS_INVALID_LOOKUP)) {
	if (bad_output_value) {
	    erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
	    erts_dsprintf(dsbufp, "Bad value on output port '%s'\n", prt->name);
	    erts_send_error_to_logger_nogl(dsbufp);
	}
	if (bang_op)
	    send_badsig(prt);
    } /* not invalid */
} /* behaved accordingly */

static int
port_badsig(Port *prt, erts_aint32_t state, int op,
            ErtsProc2PortSigData *sigdp) {
    if (op == ERTS_PROC2PORT_SIG_EXEC)
	badsig_received(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BANG_OP,
			prt,
			state,
			sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BAD_OUTPUT);
    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
	port_sched_op_reply(sigdp->caller, sigdp->ref, am_badarg, prt);
    return ERTS_PORT_REDS_BADSIG;
} /* port_badsig */
/* bad_port_signal() will
 * - preserve signal order of signals.
 * - send a 'badsig' exit signal to connected process if 'from' is an
 *   internal pid and the port is alive when the bad signal reaches
 *   it.
 */

static ErtsPortOpResult
bad_port_signal(Process *c_p,
		int flags,
		Port *prt,
		Eterm from,
		Eterm *refp,
		Eterm port_op)
{
    ErtsProc2PortSigData *sigdp;
    ErtsTryImmDrvCallResult try_call_res;
    ErtsTryImmDrvCallState try_call_state
	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
	    c_p,
	    prt,
	    ERTS_PORT_SFLGS_INVALID_LOOKUP,
	    0,
	    !refp,
	    port_op);

    try_call_res = try_imm_drv_call(&try_call_state);
    switch (try_call_res) {
    case ERTS_TRY_IMM_DRV_CALL_OK:
	badsig_received(flags & ERTS_PORT_SIG_FLG_BANG_OP,
			prt,
			try_call_state.state,
			flags & ERTS_PORT_SIG_FLG_BAD_OUTPUT);
	finalize_imm_drv_call(&try_call_state);
	if (c_p)
	    BUMP_REDS(c_p, ERTS_PORT_REDS_BADSIG);
	return ERTS_PORT_OP_BADARG;
    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
	return ERTS_PORT_OP_DROPPED;
    case ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS:
    case ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK:
	/* Schedule badsig() call instead... */
	break;
    }

    sigdp = erts_port_task_alloc_p2p_sig_data();
    sigdp->flags = (flags & ~ERTS_P2P_SIG_TYPE_MASK) | ERTS_P2P_SIG_TYPE_BAD;

    return erts_schedule_proc2port_signal(c_p,
					  prt,
					  c_p->common.id,
					  refp,
					  sigdp,
					  0,
					  NULL,
					  port_badsig);
}


/*
 * Driver outputv() callback
 */

static ERTS_INLINE void
call_driver_outputv(int bang_op,
		    Eterm caller,
		    Eterm from,
		    Port *prt,
		    erts_driver_t *drv,
		    ErlIOVec *evp)
{
    /*
     * if (bang_op)
     *   we are part of a "Prt ! {From, {command, Data}}" operation
     * else
     *   we are part of a call to port_command/[2,3]
     * behave accordingly...
     */
    if (bang_op && from != ERTS_PORT_GET_CONNECTED(prt))
	send_badsig(prt);
    else {
	ErtsSchedulerData *esdp = erts_get_scheduler_data();
	ErlDrvSizeT size = evp->size;
	ERTS_MSACC_PUSH_AND_SET_STATE_M(ERTS_MSACC_STATE_PORT);

	ERTS_LC_ASSERT(erts_lc_is_port_locked(prt)
			   || ERTS_IS_CRASH_DUMPING);


        if (IS_TRACED_FL(prt, F_TRACE_RECEIVE))
            trace_port_receive(prt, caller, am_commandv, evp);

#ifdef USE_VM_PROBES
	if (DTRACE_ENABLED(driver_outputv)) {
	    DTRACE_FORMAT_COMMON_PID_AND_PORT(caller, prt);
	    DTRACE4(driver_outputv, process_str, port_str, prt->name, size);
	}
#endif
#ifdef USE_LTTNG_VM_TRACEPOINTS
        if (LTTNG_ENABLED(driver_outputv)) {
            lttng_decl_portbuf(port_str);
            lttng_decl_procbuf(proc_str);
            lttng_pid_to_str(caller, proc_str);
            lttng_port_to_str(prt, port_str);
            LTTNG4(driver_outputv, proc_str, port_str, prt->name, size);
        }
#endif

	prt->caller = caller;
	(*drv->outputv)((ErlDrvData) prt->drv_data, evp);
	prt->caller = NIL;

	prt->bytes_out += size;
	if (esdp)
	    esdp->io.out += (Uint64) size;
	else
	    erts_atomic64_add_nob(&bytes_out, (erts_aint64_t) size);

	ERTS_MSACC_POP_STATE_M();
    }
}

static ERTS_INLINE void
cleanup_scheduled_outputv(ErlIOVec *ev, ErlDrvBinary *cbinp)
{
    int i;
    /* Need to free all binaries */
    for (i = 1; i < ev->vsize; i++)
        driver_free_binary(ev->binv[i]);
    if (cbinp)
	driver_free_binary(cbinp);
}

static int
port_sig_outputv(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
{
    Eterm reply;

    switch (op) {
    case ERTS_PROC2PORT_SIG_EXEC:
	/* Execution of a scheduled outputv() call */

	ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));

	if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP)
	    reply = am_badarg;
	else {
	    call_driver_outputv(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BANG_OP,
				sigdp->caller,
				sigdp->u.outputv.from,
				prt,
				prt->drv_ptr,
				sigdp->u.outputv.evp);
	    reply = am_true;
	}
	break;
    case ERTS_PROC2PORT_SIG_ABORT_NOSUSPEND:
	reply = am_false;
	break;
    default:
	reply = am_badarg;
	break;
    }

    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
	port_sched_op_reply(sigdp->caller, sigdp->ref, reply, prt);

    cleanup_scheduled_outputv(sigdp->u.outputv.evp,
			      sigdp->u.outputv.cbinp);

    return ERTS_PORT_REDS_CMD_OUTPUTV;
}

/*
 * Driver output() callback
 */

static ERTS_INLINE void
call_driver_output(int bang_op,
		   Eterm caller,
		   Eterm from,
		   Port *prt,
		   erts_driver_t *drv,
		   char *bufp,
		   ErlDrvSizeT size)
{
    /*
     * if (bang_op)
     *   we are part of a "Prt ! {From, {command, Data}}" operation
     * else
     *   we are part of a call to port_command/[2,3]
     * behave accordingly...
     */
    if (bang_op && from != ERTS_PORT_GET_CONNECTED(prt))
	send_badsig(prt);
    else {
	ErtsSchedulerData *esdp = erts_get_scheduler_data();
        ERTS_MSACC_PUSH_AND_SET_STATE_M(ERTS_MSACC_STATE_PORT);
	ERTS_LC_ASSERT(erts_lc_is_port_locked(prt)
			   || ERTS_IS_CRASH_DUMPING);

#ifdef USE_VM_PROBES
	if (DTRACE_ENABLED(driver_output)) {
	    DTRACE_FORMAT_COMMON_PID_AND_PORT(caller, prt);
	    DTRACE4(driver_output, process_str, port_str, prt->name, size);
	}
#endif
#ifdef USE_LTTNG_VM_TRACEPOINTS
        if (LTTNG_ENABLED(driver_output)) {
            lttng_decl_portbuf(port_str);
            lttng_decl_procbuf(proc_str);
            lttng_pid_to_str(caller, proc_str);
            lttng_port_to_str(prt, port_str);
            LTTNG4(driver_output, proc_str, port_str, prt->name, size);
        }
#endif

        if (IS_TRACED_FL(prt, F_TRACE_RECEIVE))
            trace_port_receive(prt, caller, am_command, bufp, size);

	prt->caller = caller;
	(*drv->output)((ErlDrvData) prt->drv_data, bufp, size);
	prt->caller = NIL;

	prt->bytes_out += size;
	if (esdp)
	    esdp->io.out += (Uint64) size;
	else
	    erts_atomic64_add_nob(&bytes_out, (erts_aint64_t) size);

	ERTS_MSACC_POP_STATE_M();
    }
}

static ERTS_INLINE void
cleanup_scheduled_output(char *bufp)
{
    erts_free(ERTS_ALC_T_DRV_CMD_DATA, bufp);
}

static int
port_sig_output(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
{
    Eterm reply;

    switch (op) {
    case ERTS_PROC2PORT_SIG_EXEC:
	/* Execution of a scheduled output() call */

	ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));

	if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP)
	    reply = am_badarg;
	else {
	    call_driver_output(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BANG_OP,
			       sigdp->caller,
			       sigdp->u.output.from,
			       prt,
			       prt->drv_ptr,
			       sigdp->u.output.bufp,
			       sigdp->u.output.size);
	    reply = am_true;
	}
	break;
    case ERTS_PROC2PORT_SIG_ABORT_NOSUSPEND:
	reply = am_false;
	break;
    default:
	reply = am_badarg;
	break;
    }

    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
	port_sched_op_reply(sigdp->caller, sigdp->ref, reply, prt);

    cleanup_scheduled_output(sigdp->u.output.bufp);

    return ERTS_PORT_REDS_CMD_OUTPUT;
}


/*
 * This erts_port_output will always create a port task.
 * The call is treated as a port_command call, i.e. no
 * badsig i generated if the input in invalid. However
 * an error_logger message is generated.
 */
int
erts_port_output_async(Port *prt, Eterm from, Eterm list)
{

    ErtsProc2PortSigData *sigdp;
    erts_driver_t *drv = prt->drv_ptr;
    size_t size;
    int task_flags;
    ErtsProc2PortSigCallback port_sig_callback;
    ErtsIOQBinary *cbin = NULL;
    ErtsIOVec *evp = NULL;
    char *buf = NULL;
    ErtsPortTaskHandle *ns_pthp;

    if (drv->outputv) {
	SysIOVec* ivp;
	ErtsIOQBinary**  bvp;
        int vsize;
	Uint csize;
	Uint pvsize;
	Uint pcsize;
        size_t iov_offset, binv_offset, alloc_size;
        Uint blimit = 0;
        char *ptr;
        int i;

        if (erts_ioq_iodata_vec_len(list, &vsize, &csize, &pvsize, &pcsize,
                                    &size, ERL_SMALL_IO_BIN_LIMIT))
            goto bad_value;

        /* To pack or not to pack (small binaries) ...? */
        if (vsize >= SMALL_WRITE_VEC) {
            /* Do pack */
            vsize = pvsize + 1;
            csize = pcsize;
            blimit = ERL_SMALL_IO_BIN_LIMIT;
        }
        if (csize) {
            cbin = (ErtsIOQBinary *)driver_alloc_binary(csize);
            if (!cbin)
                erts_alloc_enomem(ERTS_ALC_T_DRV_BINARY, ERTS_SIZEOF_Binary(csize));
        }

        iov_offset = ERTS_ALC_DATA_ALIGN_SIZE(sizeof(ErlIOVec));
	binv_offset = iov_offset;
        binv_offset += ERTS_ALC_DATA_ALIGN_SIZE((vsize+1)*sizeof(SysIOVec));
        alloc_size = binv_offset;
	alloc_size += (vsize+1)*sizeof(ErtsIOQBinary *);

        sigdp = erts_port_task_alloc_p2p_sig_data_extra(alloc_size, (void**)&ptr);

        evp = (ErtsIOVec *) ptr;
        ivp = evp->driver.iov = (SysIOVec *) (ptr + iov_offset);
        bvp = evp->common.binv = (ErtsIOQBinary **) (ptr + binv_offset);

        ivp[0].iov_base = NULL;
	ivp[0].iov_len = 0;
	bvp[0] = NULL;

        evp->driver.vsize = erts_ioq_iodata_to_vec(list, ivp+1, bvp+1, cbin,
                                                   blimit, 1);
        if (evp->driver.vsize < 0) {
            erts_free(ERTS_ALC_T_DRV_CMD_DATA, evp);
            driver_free_binary(&cbin->driver);
            goto bad_value;
        }
#if 0
	/* This assertion may say something useful, but it can
        be falsified during the emulator test suites. */
	ASSERT(evp->vsize == vsize);
#endif
	evp->driver.vsize++;
	evp->driver.size = size;  /* total size */

        /* Need to increase refc on all binaries */
        for (i = 1; i < evp->driver.vsize; i++)
            if (bvp[i])
                driver_binary_inc_refc(&bvp[i]->driver);

	sigdp->flags = ERTS_P2P_SIG_TYPE_OUTPUTV;
	sigdp->u.outputv.from = from;
	sigdp->u.outputv.evp = &evp->driver;
	sigdp->u.outputv.cbinp = &cbin->driver;
	port_sig_callback = port_sig_outputv;
    } else {
        ErlDrvSizeT ERTS_DECLARE_DUMMY(r);

	/*
	 * Apparently there exist code that write 1 byte to
	 * much in buffer. Where it resides I don't know, but
	 * we can live with one byte extra allocated...
	 */

        if (erts_iolist_size(list, &size))
            goto bad_value;

        buf = erts_alloc(ERTS_ALC_T_DRV_CMD_DATA, size + 1);

        r = erts_iolist_to_buf(list, buf, size);
        ASSERT(ERTS_IOLIST_TO_BUF_SUCCEEDED(r));

	sigdp = erts_port_task_alloc_p2p_sig_data();
	sigdp->flags = ERTS_P2P_SIG_TYPE_OUTPUT;
	sigdp->u.output.from = from;
	sigdp->u.output.bufp = buf;
	sigdp->u.output.size = size;
	port_sig_callback = port_sig_output;
    }
    ns_pthp = NULL;
    task_flags = 0;

    erts_schedule_proc2port_signal(NULL,
                                   prt,
                                   ERTS_INVALID_PID,
                                   NULL,
                                   sigdp,
                                   task_flags,
                                   ns_pthp,
                                   port_sig_callback);

    return 1;

bad_value:

    /*
     * We call badsig directly here as this function is called with
     * the main lock of the calling process still held.
     * At the moment this operation is always not a bang_op, so
     * only an error_logger message should be generated, no badsig.
    */

    badsig_received(0, prt, erts_atomic32_read_nob(&prt->state), 1);

    return 0;

}

ErtsPortOpResult
erts_port_output(Process *c_p,
		 int flags,
		 Port *prt,
		 Eterm from,
		 Eterm list,
		 Eterm *refp)
{
    ErtsPortOpResult res;
    ErtsProc2PortSigData *sigdp = NULL;
    erts_driver_t *drv = prt->drv_ptr;
    size_t size;
    int try_call;
    erts_aint32_t sched_flags, busy_flgs, invalid_flags;
    int task_flags;
    ErtsProc2PortSigCallback port_sig_callback;
    ErtsIOQBinary *cbin = NULL;
    ErtsIOVec *evp = NULL;
    char *buf = NULL;
    int force_immediate_call = (flags & ERTS_PORT_SIG_FLG_FORCE_IMM_CALL);
    int async_nosuspend;
    ErtsPortTaskHandle *ns_pthp;

    ASSERT((flags & ~(ERTS_PORT_SIG_FLG_BANG_OP
		      | ERTS_PORT_SIG_FLG_ASYNC
		      | ERTS_PORT_SIG_FLG_NOSUSPEND
		      | ERTS_PORT_SIG_FLG_FORCE
		      | ERTS_PORT_SIG_FLG_FORCE_IMM_CALL)) == 0);

    busy_flgs = ((flags & ERTS_PORT_SIG_FLG_FORCE)
		 ? ((erts_aint32_t) 0)
		 : ERTS_PTS_FLGS_BUSY);
    invalid_flags = busy_flgs;
    if (!refp)
	invalid_flags |= ERTS_PTS_FLG_PARALLELISM;

    /*
     * Assumes caller have checked that port is valid...
     */

    sched_flags = erts_atomic32_read_nob(&prt->sched.flags);
    if (sched_flags & (busy_flgs|ERTS_PTS_FLG_EXIT))
	return ((sched_flags & ERTS_PTS_FLG_EXIT)
		? ERTS_PORT_OP_DROPPED
		: ERTS_PORT_OP_BUSY);

    async_nosuspend = ((flags & (ERTS_PORT_SIG_FLG_ASYNC
				 | ERTS_PORT_SIG_FLG_NOSUSPEND
				 | ERTS_PORT_SIG_FLG_FORCE))
		      == (ERTS_PORT_SIG_FLG_ASYNC
			  | ERTS_PORT_SIG_FLG_NOSUSPEND));

    try_call = (force_immediate_call /* crash dumping */
		|| !(sched_flags & (invalid_flags
				    | ERTS_PTS_FLGS_FORCE_SCHEDULE_OP)));

#ifdef USE_VM_PROBES
    if(DTRACE_ENABLED(port_command)) {
	DTRACE_FORMAT_COMMON_PID_AND_PORT(c_p ? c_p->common.id : ERTS_INVALID_PID, prt);
	DTRACE4(port_command, process_str, port_str, prt->name, "command");
    }
#endif
    if (drv->outputv) {
	ErtsIOVec ev;
	SysIOVec iv[SMALL_WRITE_VEC];
	ErtsIOQBinary* bv[SMALL_WRITE_VEC];
	SysIOVec* ivp;
	ErtsIOQBinary**  bvp;
	int vsize;
	Uint csize;
	Uint pvsize;
	Uint pcsize;
	Uint blimit;
	size_t iov_offset, binv_offset, alloc_size;

	if (erts_ioq_iodata_vec_len(list, &vsize, &csize, &pvsize, &pcsize,
                                    &size, ERL_SMALL_IO_BIN_LIMIT))
	    goto bad_value;

	iov_offset = ERTS_ALC_DATA_ALIGN_SIZE(sizeof(ErlIOVec));
	binv_offset = iov_offset;
	binv_offset += ERTS_ALC_DATA_ALIGN_SIZE((vsize+1)*sizeof(SysIOVec));
	alloc_size = binv_offset;
	alloc_size += (vsize+1)*sizeof(ErtsIOQBinary *);

	if (try_call && vsize < SMALL_WRITE_VEC) {
	    ivp = ev.common.iov = iv;
	    bvp = ev.common.binv = bv;
	    evp = &ev;
	}
	else {
            char *ptr;
            if (try_call) {
                ptr = erts_alloc(ERTS_ALC_T_TMP, alloc_size);
            } else {
                sigdp = erts_port_task_alloc_p2p_sig_data_extra(
                    alloc_size, (void**)&ptr);
            }
	    evp = (ErtsIOVec *) ptr;
	    ivp = evp->driver.iov = (SysIOVec *) (ptr + iov_offset);
	    bvp = evp->common.binv = (ErtsIOQBinary **) (ptr + binv_offset);
	}

	/* To pack or not to pack (small binaries) ...? */
	if (vsize < SMALL_WRITE_VEC) {
	    /* Do NOT pack */
	    blimit = 0;
	}
	else {
	    /* Do pack */
	    vsize = pvsize + 1;
	    csize = pcsize;
	    blimit = ERL_SMALL_IO_BIN_LIMIT;
	}
	/* Use vsize and csize from now on */

        if (csize) {
            cbin = (ErtsIOQBinary *)driver_alloc_binary(csize);
            if (!cbin)
                erts_alloc_enomem(ERTS_ALC_T_DRV_BINARY, ERTS_SIZEOF_Binary(csize));
        }

	/* Element 0 is for driver usage to add header block */
	ivp[0].iov_base = NULL;
	ivp[0].iov_len = 0;
	bvp[0] = NULL;
	evp->driver.vsize = erts_ioq_iodata_to_vec(list, ivp+1, bvp+1,
                                                   cbin, blimit, 1);
	if (evp->driver.vsize < 0) {
            if (evp != &ev) {
                if (try_call)
                    erts_free(ERTS_ALC_T_TMP, evp);
                else
                    erts_port_task_free_p2p_sig_data(sigdp);
            }
            driver_free_binary(&cbin->driver);
	    goto bad_value;
	}
#if 0
	/* This assertion may say something useful, but it can
	   be falsified during the emulator test suites. */
	ASSERT(evp->vsize == vsize);
#endif
	evp->driver.vsize++;
	evp->driver.size = size;  /* total size */

	if (!try_call) {
	    int i;
	    /* Need to increase refc on all binaries */
	    for (i = 1; i < evp->driver.vsize; i++)
                if (bvp[i])
                    driver_binary_inc_refc(&bvp[i]->driver);
	}
	else {
	    int i;
	    ErtsIOVec *new_evp;
	    ErtsTryImmDrvCallResult try_call_res;
	    ErtsTryImmDrvCallState try_call_state
		= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
		    c_p,
		    prt,
		    ERTS_PORT_SFLGS_INVALID_LOOKUP,
		    invalid_flags,
		    !refp,
		    am_command);

	    try_call_state.pre_chk_sched_flags = 0; /* already checked */
	    if (force_immediate_call)
		try_call_res = force_imm_drv_call(&try_call_state);
	    else
		try_call_res = try_imm_drv_call(&try_call_state);
	    switch (try_call_res) {
	    case ERTS_TRY_IMM_DRV_CALL_OK:
		call_driver_outputv(flags & ERTS_PORT_SIG_FLG_BANG_OP,
				    c_p ? c_p->common.id : ERTS_INVALID_PID,
				    from,
				    prt,
				    drv,
				    &evp->driver);
		if (force_immediate_call)
		    finalize_force_imm_drv_call(&try_call_state);
		else
		    finalize_imm_drv_call(&try_call_state);
		/* Fall through... */
	    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
		driver_free_binary(&cbin->driver);
		if (evp != &ev) {
                    ASSERT(!sigdp);
		    erts_free(ERTS_ALC_T_TMP, evp);
                }
		if (try_call_res != ERTS_TRY_IMM_DRV_CALL_OK)
		    return ERTS_PORT_OP_DROPPED;
		if (c_p)
		    BUMP_REDS(c_p, ERTS_PORT_REDS_CMD_OUTPUTV);
		return ERTS_PORT_OP_DONE;
	    case ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS:
		sched_flags = try_call_state.sched_flags;
		if (async_nosuspend
		    && (sched_flags & (busy_flgs|ERTS_PTS_FLG_EXIT))) {
		    driver_free_binary(&cbin->driver);
                    if (evp != &ev) {
                        ASSERT(!sigdp);
			erts_free(ERTS_ALC_T_TMP, evp);
                    }
		    return ((sched_flags & ERTS_PTS_FLG_EXIT)
			    ? ERTS_PORT_OP_DROPPED
			    : ERTS_PORT_OP_BUSY);
		}
	    case ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK:
		/* Schedule outputv() call instead... */
		break;
	    }

	    /* Need to increase refc on all binaries */
	    for (i = 1; i < evp->driver.vsize; i++)
		if (bvp[i])
		    driver_binary_inc_refc(&bvp[i]->driver);

            /* The port task and iovec is allocated in the
               same structure as an optimization. This
               is especially important in erts_port_output_async
               of when !try_call */
            ASSERT(sigdp == NULL);
            sigdp = erts_port_task_alloc_p2p_sig_data_extra(
                alloc_size, (void**)&new_evp);

	    if (evp != &ev) {
                /* Copy from TMP alloc to port task */
		sys_memcpy((void *) new_evp, (void *) evp, alloc_size);
		new_evp->driver.iov = (SysIOVec *) (((char *) new_evp)
                                                    + iov_offset);
		bvp = new_evp->common.binv = (ErtsIOQBinary **) (((char *) new_evp)
                                                                 + binv_offset);

#ifdef DEBUG
		ASSERT(new_evp->driver.vsize == evp->driver.vsize);
		ASSERT(new_evp->driver.size == evp->driver.size);
		for (i = 0; i < evp->driver.vsize; i++) {
		    ASSERT(new_evp->driver.iov[i].iov_len == evp->driver.iov[i].iov_len);
		    ASSERT(new_evp->driver.iov[i].iov_base == evp->driver.iov[i].iov_base);
		    ASSERT(new_evp->driver.binv[i] == evp->driver.binv[i]);
		}
#endif

		erts_free(ERTS_ALC_T_TMP, evp);
	    }
	    else { /* from stack allocated structure; offsets may differ */

		sys_memcpy((void *) new_evp, (void *) evp, sizeof(ErlIOVec));
		new_evp->driver.iov = (SysIOVec *) (((char *) new_evp)
                                                    + iov_offset);
		sys_memcpy((void *) new_evp->driver.iov,
			   (void *) evp->driver.iov,
			   evp->driver.vsize * sizeof(SysIOVec));
		new_evp->common.binv = (ErtsIOQBinary **) (((char *) new_evp)
                                                           + binv_offset);
		sys_memcpy((void *) new_evp->common.binv,
			   (void *) evp->common.binv,
			   evp->driver.vsize * sizeof(ErtsIOQBinary *));

#ifdef DEBUG
		ASSERT(new_evp->driver.vsize == evp->driver.vsize);
		ASSERT(new_evp->driver.size == evp->driver.size);
		for (i = 0; i < evp->driver.vsize; i++) {
		    ASSERT(new_evp->driver.iov[i].iov_len == evp->driver.iov[i].iov_len);
		    ASSERT(new_evp->driver.iov[i].iov_base == evp->driver.iov[i].iov_base);
		    ASSERT(new_evp->driver.binv[i] == evp->driver.binv[i]);
		}
#endif

	    }

	    evp = new_evp;
	}

	sigdp->flags = ERTS_P2P_SIG_TYPE_OUTPUTV;
	sigdp->u.outputv.from = from;
	sigdp->u.outputv.evp = &evp->driver;
	sigdp->u.outputv.cbinp = &cbin->driver;
	port_sig_callback = port_sig_outputv;
    }
    else {
	ErlDrvSizeT r;

	/*
	 * Apparently there exist code that write 1 byte to
	 * much in buffer. Where it resides I don't know, but
	 * we can live with one byte extra allocated...
	 */

	if (!try_call) {
	    if (erts_iolist_size(list, &size))
		goto bad_value;

	    buf = erts_alloc(ERTS_ALC_T_DRV_CMD_DATA, size + 1);

	    r = erts_iolist_to_buf(list, buf, size);
	    ASSERT(ERTS_IOLIST_TO_BUF_SUCCEEDED(r));
	}
	else {
	    char *new_buf;
	    ErtsTryImmDrvCallResult try_call_res;
	    ErtsTryImmDrvCallState try_call_state
		= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
		    c_p,
		    prt,
		    ERTS_PORT_SFLGS_INVALID_LOOKUP,
		    invalid_flags,
		    !refp,
		    am_command);

	    /* Try with an 8KB buffer first (will often be enough I guess). */
	    size = 8*1024;

	    buf = erts_alloc(ERTS_ALC_T_TMP, size + 1);
	    r = erts_iolist_to_buf(list, buf, size);

	    if (ERTS_IOLIST_TO_BUF_SUCCEEDED(r)) {
		ASSERT(r <= size);
		size -= r;
	    }
	    else {
		erts_free(ERTS_ALC_T_TMP, buf);
		if (r == ERTS_IOLIST_TO_BUF_TYPE_ERROR)
		    goto bad_value;
		ASSERT(r == ERTS_IOLIST_TO_BUF_OVERFLOW);
		if (erts_iolist_size(list, &size))
		    goto bad_value;
		buf = erts_alloc(ERTS_ALC_T_TMP, size + 1); 
		r = erts_iolist_to_buf(list, buf, size);
		ASSERT(ERTS_IOLIST_TO_BUF_SUCCEEDED(r));
	    }

	    try_call_state.pre_chk_sched_flags = 0; /* already checked */
	    if (force_immediate_call)
		try_call_res = force_imm_drv_call(&try_call_state);
	    else
		try_call_res = try_imm_drv_call(&try_call_state);
	    switch (try_call_res) {
	    case ERTS_TRY_IMM_DRV_CALL_OK:
		call_driver_output(flags & ERTS_PORT_SIG_FLG_BANG_OP,
				   c_p ? c_p->common.id : ERTS_INVALID_PID,
				   from,
				   prt,
				   drv,
				   buf,
				   size);
		if (force_immediate_call)
		    finalize_force_imm_drv_call(&try_call_state);
		else
		    finalize_imm_drv_call(&try_call_state);
		/* Fall through... */
	    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
		erts_free(ERTS_ALC_T_TMP, buf);
		if (try_call_res != ERTS_TRY_IMM_DRV_CALL_OK)
		    return ERTS_PORT_OP_DROPPED;
		if (c_p)
		    BUMP_REDS(c_p, ERTS_PORT_REDS_CMD_OUTPUT);
		return ERTS_PORT_OP_DONE;
	    case ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS:
		sched_flags = try_call_state.sched_flags;
		if (async_nosuspend
		    && (sched_flags & (busy_flgs|ERTS_PTS_FLG_EXIT))) {
		    erts_free(ERTS_ALC_T_TMP, buf);
		    return ((sched_flags & ERTS_PTS_FLG_EXIT)
			    ? ERTS_PORT_OP_DROPPED
			    : ERTS_PORT_OP_BUSY);
		}
	    case ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK:
		/* Schedule outputv() call instead... */
		break;
	    }

	    new_buf = erts_alloc(ERTS_ALC_T_DRV_CMD_DATA, size + 1);
	    sys_memcpy(new_buf, buf, size);
	    erts_free(ERTS_ALC_T_TMP, buf);
	    buf = new_buf;
	}

	sigdp = erts_port_task_alloc_p2p_sig_data();
	sigdp->flags = ERTS_P2P_SIG_TYPE_OUTPUT;
	sigdp->u.output.from = from;
	sigdp->u.output.bufp = buf;
	sigdp->u.output.size = size;
	port_sig_callback = port_sig_output;
    }

    task_flags = ERTS_PT_FLG_WAIT_BUSY;
    sigdp->flags |= flags;
    ns_pthp = NULL;
    if (flags & (ERTS_P2P_SIG_DATA_FLG_FORCE|ERTS_P2P_SIG_DATA_FLG_NOSUSPEND)) {
	task_flags = 0;
	if (flags & ERTS_P2P_SIG_DATA_FLG_FORCE)
	    sigdp->flags &= ~ERTS_P2P_SIG_DATA_FLG_NOSUSPEND;
	else if (async_nosuspend) {
	    ErtsSchedulerData *esdp = (c_p
				       ? erts_proc_sched_data(c_p)
				       : erts_get_scheduler_data());
	    ASSERT(esdp);
	    ns_pthp = &esdp->nosuspend_port_task_handle;
	    sigdp->flags &= ~ERTS_P2P_SIG_DATA_FLG_NOSUSPEND;
	}
	else if (flags & ERTS_P2P_SIG_DATA_FLG_NOSUSPEND)
	    task_flags = ERTS_PT_FLG_NOSUSPEND;
    }

    ASSERT(ns_pthp || !async_nosuspend);
    ASSERT(async_nosuspend || !ns_pthp);

    res = erts_schedule_proc2port_signal(c_p,
					 prt,
					 c_p ? c_p->common.id : ERTS_INVALID_PID,
					 refp,
					 sigdp,
					 task_flags,
					 ns_pthp,
					 port_sig_callback);

    if (res != ERTS_PORT_OP_SCHEDULED) {
	return res;
    }

    if (!(flags & ERTS_PORT_SIG_FLG_FORCE)) {
	sched_flags = erts_atomic32_read_acqb(&prt->sched.flags);
	if (!(sched_flags & ERTS_PTS_FLG_BUSY_PORT)) {
	    if (async_nosuspend)
		erts_port_task_tmp_handle_detach(ns_pthp);
	}
	else {
	    if (!async_nosuspend)
		return ERTS_PORT_OP_BUSY_SCHEDULED;
	    else {
		if (erts_port_task_abort(ns_pthp) == 0)
		    return ERTS_PORT_OP_BUSY;
		else
		    erts_port_task_tmp_handle_detach(ns_pthp);
	    }
	}
    }
    return res;

bad_value:

    flags |= ERTS_PORT_SIG_FLG_BAD_OUTPUT;
    return bad_port_signal(c_p, flags, prt, from, refp, am_command);
}

static ERTS_INLINE ErtsPortOpResult
call_deliver_port_exit(int bang_op,
		       Eterm from,
		       Port *prt,
		       erts_aint32_t state,
		       Eterm reason,
		       int broken_link)
{
    /*
     * if (bang_op)
     *   we are part of a "Prt ! {From, close}" operation
     * else
     *   we are part of a call to port_close(Port)
     * behave accordingly...
     */

    if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP)
	return ERTS_PORT_OP_DROPPED;

    if (bang_op && from != ERTS_PORT_GET_CONNECTED(prt)) {
	send_badsig(prt);
	return ERTS_PORT_OP_DROPPED;
    }

    if (broken_link) {
	ErtsLink *lnk = erts_link_tree_lookup(ERTS_P_LINKS(prt), from);
	if (!lnk) 
	    return ERTS_PORT_OP_DROPPED;
        erts_link_tree_delete(&ERTS_P_LINKS(prt), lnk);
        erts_link_release(lnk);
    }

    if (IS_TRACED_FL(prt, F_TRACE_RECEIVE))
        trace_port_receive(prt, from, am_close);

    if (!erts_deliver_port_exit(prt, from, reason, bang_op, broken_link))
	return ERTS_PORT_OP_DROPPED;

#ifdef USE_VM_PROBES
    if(DTRACE_ENABLED(port_command) && bang_op) {
	DTRACE_FORMAT_COMMON_PID_AND_PORT(from, prt);
	DTRACE4(port_command, process_str, port_str, prt->name, "close");
    }
#endif

    return ERTS_PORT_OP_DONE;
}

static int
port_sig_exit(Port *prt,
	      erts_aint32_t state,
	      int op,
	      ErtsProc2PortSigData *sigdp)
{
    Eterm msg = am_badarg;
    if (op == ERTS_PROC2PORT_SIG_EXEC) {
	ErtsPortOpResult res;
	int bang_op = sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BANG_OP;
	int broken_link = sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BROKEN_LINK;
	res = call_deliver_port_exit(bang_op,
				     sigdp->u.exit.from,
				     prt,
				     state,
				     sigdp->u.exit.reason,
				     broken_link);

	if (res == ERTS_PORT_OP_DONE)
	    msg = am_true;
    }
    if (sigdp->u.exit.bp)
	free_message_buffer(sigdp->u.exit.bp);
    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
	port_sched_op_reply(sigdp->caller, sigdp->ref, msg, prt);

    return ERTS_PORT_REDS_EXIT;
}

ErtsPortOpResult
erts_port_exit(Process *c_p,
	       int flags,
	       Port *prt,
	       Eterm from,
	       Eterm reason,
	       Eterm *refp)
{
    ErtsPortOpResult res;
    ErtsProc2PortSigData *sigdp;
    ErlHeapFragment *bp = NULL;

    ASSERT((flags & ~(ERTS_PORT_SIG_FLG_BANG_OP
		      | ERTS_PORT_SIG_FLG_ASYNC
		      | ERTS_PORT_SIG_FLG_BROKEN_LINK
		      | ERTS_PORT_SIG_FLG_FORCE_SCHED)) == 0);

#ifndef __WIN32__
    if (prt->drv_ptr == &forker_driver)
        return ERTS_PORT_OP_DROPPED;
#endif

    if (!(flags & ERTS_PORT_SIG_FLG_FORCE_SCHED)) {
	ErtsTryImmDrvCallState try_call_state
	    = ERTS_INIT_TRY_IMM_DRV_CALL_STATE(c_p,
					       prt,
					       ERTS_PORT_SFLGS_INVALID_LOOKUP,
					       0,
					       !refp,
					       am_close);


	switch (try_imm_drv_call(&try_call_state)) {
	case ERTS_TRY_IMM_DRV_CALL_OK: {
	    res = call_deliver_port_exit(flags & ERTS_PORT_SIG_FLG_BANG_OP,
					 from,
					 prt,
					 try_call_state.state,
					 reason,
					 flags & ERTS_PORT_SIG_FLG_BROKEN_LINK);
	    finalize_imm_drv_call(&try_call_state);
	    if (res == ERTS_PORT_OP_DONE && c_p)
		BUMP_REDS(c_p, ERTS_PORT_REDS_EXIT);
	    return res;
	}
	case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
	    return ERTS_PORT_OP_DROPPED;
	default:
	    /* Schedule call instead... */
	    break;
	}
    }

    sigdp = erts_port_task_alloc_p2p_sig_data();
    sigdp->flags = ERTS_P2P_SIG_TYPE_EXIT | flags;
    sigdp->u.exit.from = from;

    if (is_immed(reason)) {
	sigdp->u.exit.reason = reason;
	sigdp->u.exit.bp = NULL;
    }
    else {
	Eterm *hp;
	Uint hsz = size_object(reason);
	bp = new_message_buffer(hsz);
	sigdp->u.exit.bp = bp;
	hp = bp->mem;
	sigdp->u.exit.reason = copy_struct(reason,
					   hsz,
					   &hp,
					   &bp->off_heap);
    }

    return erts_schedule_proc2port_signal(c_p,
                                          prt,
                                          c_p ? c_p->common.id : from,
                                          refp,
                                          sigdp,
                                          0,
                                          NULL,
                                          port_sig_exit);
}

static ErtsPortOpResult
set_port_connected(int bang_op,
		   Eterm from,
		   Port *prt,
		   erts_aint32_t state,
		   Eterm connect)
{
    /*
     * if (bang_op)
     *   we are part of a "Prt ! {From, {connect, Connect}}" operation
     * else
     *   we are part of a call to port_connect(Port, Connect)
     * behave accordingly...
     */

    if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP)
	return ERTS_PORT_OP_DROPPED;

    if (bang_op) { /* Bang operation */
	if (is_not_internal_pid(connect) || ERTS_PORT_GET_CONNECTED(prt) != from) {
	    send_badsig(prt);
	    return ERTS_PORT_OP_DROPPED;
	}

        if (IS_TRACED_FL(prt, F_TRACE_RECEIVE))
            trace_port_receive(prt, from, am_connect, connect);

	ERTS_PORT_SET_CONNECTED(prt, connect);
	deliver_result(prt, prt->common.id, from, am_connected);

#ifdef USE_VM_PROBES
	if(DTRACE_ENABLED(port_command)) {
	    DTRACE_FORMAT_COMMON_PID_AND_PORT(from, prt);
	    DTRACE4(port_command, process_str, port_str, prt->name, "connect");
	}
#endif
    }
    else { /* Port BIF operation */
        int created;
        ErtsLink *lnk;

        if (is_not_internal_pid(connect))
            return ERTS_PORT_OP_DROPPED;

        lnk = erts_link_internal_tree_lookup_create(&ERTS_P_LINKS(prt),
                                                    &created,
                                                    ERTS_LNK_TYPE_PORT,
                                                    connect);
        if (created) {
            ErtsLink *olnk = erts_link_internal_create(ERTS_LNK_TYPE_PORT,
                                                       prt->common.id);
            if (!erts_proc_sig_send_link(&prt->common, prt->common.id,
                                         connect, olnk)) {
                erts_link_tree_delete(&ERTS_P_LINKS(prt), lnk);
                erts_link_internal_release(lnk);
                erts_link_internal_release(olnk);
                return ERTS_PORT_OP_DROPPED;
            }
            if (IS_TRACED_FL(prt, F_TRACE_PORTS))
                trace_port(prt, am_getting_linked, connect);
        }

#ifdef USE_VM_PROBES
	if (DTRACE_ENABLED(port_connect)) {
            Eterm old_connected = ERTS_PORT_GET_CONNECTED(prt);
            DTRACE_CHARBUF(process_str, DTRACE_TERM_BUF_SIZE);
            DTRACE_CHARBUF(port_str, DTRACE_TERM_BUF_SIZE);
            DTRACE_CHARBUF(newprocess_str, DTRACE_TERM_BUF_SIZE);

            dtrace_pid_str(old_connected, process_str);
            erts_snprintf(port_str, sizeof(DTRACE_CHARBUF_NAME(port_str)),
                          "%T", prt->common.id);
            dtrace_pid_str(connect, newprocess_str);
            DTRACE4(port_connect, process_str, port_str, prt->name, newprocess_str);
	}
#endif

	ERTS_PORT_SET_CONNECTED(prt, connect);

        if (IS_TRACED_FL(prt, F_TRACE_RECEIVE))
            trace_port_receive(prt, from, am_connect, connect);
        if (IS_TRACED_FL(prt, F_TRACE_SEND)) {
            Eterm hp[3];
            trace_port_send(prt, from, TUPLE2(hp, prt->common.id, am_connected), 1);
        }

    }

    return ERTS_PORT_OP_DONE;
}

static int
port_sig_connect(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
{
    Eterm msg = am_badarg;
    if (op == ERTS_PROC2PORT_SIG_EXEC) {
	ErtsPortOpResult res;
	res = set_port_connected(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BANG_OP,
				 sigdp->u.connect.from,
				 prt,
				 state,
				 sigdp->u.connect.connected);
	if (res == ERTS_PORT_OP_DONE)
	    msg = am_true;
    }
    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
	port_sched_op_reply(sigdp->caller, sigdp->ref, msg, prt);
    return ERTS_PORT_REDS_CONNECT;
}

ErtsPortOpResult
erts_port_connect(Process *c_p,
		  int flags,
		  Port *prt,
		  Eterm from,
		  Eterm connect,
		  Eterm *refp)
{
    ErtsProc2PortSigData *sigdp;
    Eterm connect_id;
    ErtsTryImmDrvCallState try_call_state
	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(c_p,
					   prt,
					   ERTS_PORT_SFLGS_INVALID_LOOKUP,
					   0,
					   !refp,
					   am_connect);

    ASSERT((flags & ~(ERTS_PORT_SIG_FLG_BANG_OP
		      | ERTS_PORT_SIG_FLG_ASYNC)) == 0);

    if (is_not_internal_pid(connect))
	connect_id = NIL; /* Fail in op (for signal order) */
    else
	connect_id = connect;

    switch (try_imm_drv_call(&try_call_state)) {
    case ERTS_TRY_IMM_DRV_CALL_OK: {
	ErtsPortOpResult res;
	res = set_port_connected(flags & ERTS_PORT_SIG_FLG_BANG_OP,
				 from,
				 prt,
				 try_call_state.state,
				 connect_id);
	finalize_imm_drv_call(&try_call_state);
	if (res == ERTS_PORT_OP_DONE)
	    BUMP_REDS(c_p, ERTS_PORT_REDS_CONNECT);
	return res;
    }
    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
	return ERTS_PORT_OP_DROPPED;
    default:
	/* Schedule call instead... */
	break;
    }

    sigdp = erts_port_task_alloc_p2p_sig_data();
    sigdp->flags = ERTS_P2P_SIG_TYPE_CONNECT | flags;

    sigdp->u.connect.from = from;
    sigdp->u.connect.connected = connect_id;
    
    return erts_schedule_proc2port_signal(c_p,
					  prt,
					  c_p->common.id,
					  refp,
					  sigdp,
					  0,
					  NULL,
					  port_sig_connect);
}

static void
port_unlink_failure(Port *prt, Eterm port_id, ErtsSigUnlinkOp *sulnk)
{
    erts_proc_sig_send_unlink_ack(prt ? &prt->common : NULL, port_id, sulnk);
}

static void
port_unlink(Port *prt, erts_aint32_t state, ErtsSigUnlinkOp *sulnk)
{
    if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP) {
        port_unlink_failure(prt, prt->common.id, sulnk);
    } else {
        ErtsILink *ilnk;

        ilnk = (ErtsILink *) erts_link_tree_lookup(ERTS_P_LINKS(prt),
                                                   sulnk->from);

        if (ilnk && !ilnk->unlinking) {
            if (IS_TRACED_FL(prt, F_TRACE_PORTS))
                trace_port(prt, am_getting_unlinked, sulnk->from);
            erts_link_tree_delete(&ERTS_P_LINKS(prt), &ilnk->link);
            erts_link_internal_release(&ilnk->link);
        }

        erts_proc_sig_send_unlink_ack(&prt->common, prt->common.id, sulnk);
    }
}

static int
port_sig_unlink(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
{
    if (op == ERTS_PROC2PORT_SIG_EXEC) {
        port_unlink(prt, state, sigdp->u.unlink.sulnk);
    } else {
        port_unlink_failure(prt, sigdp->u.unlink.port_id,
                            sigdp->u.unlink.sulnk);
    }

    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY) {
        port_sched_op_reply(sigdp->caller, sigdp->ref, am_true, prt);
    }

    return ERTS_PORT_REDS_UNLINK;
}

ErtsPortOpResult
erts_port_unlink(Process *c_p, Port *prt, ErtsSigUnlinkOp *sulnk, Eterm *refp)
{
    ErtsProc2PortSigData *sigdp;
    ErtsTryImmDrvCallState try_call_state
	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(c_p,
					   prt,
					   ERTS_PORT_SFLGS_DEAD,
					   0,
					   !refp,
					   am_unlink);

    ASSERT(is_internal_pid(sulnk->from));
    
    switch (try_imm_drv_call(&try_call_state)) {
    case ERTS_TRY_IMM_DRV_CALL_OK:
	port_unlink(prt, try_call_state.state, sulnk);
	finalize_imm_drv_call(&try_call_state);
	BUMP_REDS(c_p, ERTS_PORT_REDS_UNLINK);
	return ERTS_PORT_OP_DONE;
    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
        port_unlink_failure(prt, prt->common.id, sulnk);
	return ERTS_PORT_OP_DROPPED;
    default:
	/* Schedule call instead... */
	break;
    }

    sigdp = erts_port_task_alloc_p2p_sig_data();
    sigdp->flags = ERTS_P2P_SIG_TYPE_UNLINK;
    sigdp->u.unlink.port_id = prt->common.id;
    sigdp->u.unlink.sulnk = sulnk;

    return erts_schedule_proc2port_signal(c_p,
					  prt,
					  c_p->common.id,
					  refp,
					  sigdp,
					  0,
					  NULL,
					  port_sig_unlink);
}

static void
port_unlink_ack_failure(Eterm port_id, ErtsSigUnlinkOp *sulnk)
{
    erts_proc_sig_destroy_unlink_op(sulnk);
}

static void
port_unlink_ack(Port *prt, erts_aint32_t state, ErtsSigUnlinkOp *sulnk)
{
    if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP)
	port_unlink_ack_failure(prt->common.id, sulnk);
    else {
        ErtsILink *ilnk;
        ilnk = (ErtsILink *) erts_link_tree_lookup(ERTS_P_LINKS(prt),
                                                   sulnk->from);
        if (ilnk && ilnk->unlinking == sulnk->id) {
            erts_link_tree_delete(&ERTS_P_LINKS(prt), &ilnk->link);
            erts_link_internal_release(&ilnk->link);
        }
        erts_proc_sig_destroy_unlink_op(sulnk);
    }
}

static int
port_sig_unlink_ack(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
{
    if (op == ERTS_PROC2PORT_SIG_EXEC)
	port_unlink_ack(prt, state, sigdp->u.unlink_ack.sulnk);
    else
        port_unlink_ack_failure(sigdp->u.unlink_ack.port_id, sigdp->u.unlink_ack.sulnk);
    return ERTS_PORT_REDS_UNLINK_ACK;
}

ErtsPortOpResult
erts_port_unlink_ack(Process *c_p, Port *prt, ErtsSigUnlinkOp *sulnk)
{
    ErtsProc2PortSigData *sigdp;
    ErtsTryImmDrvCallState try_call_state
	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(c_p,
					   prt,
					   ERTS_PORT_SFLGS_DEAD,
					   0,
					   !0,
					   am_unlink);

    ASSERT(c_p);
    sulnk->from = c_p->common.id;
    
    switch (try_imm_drv_call(&try_call_state)) {
    case ERTS_TRY_IMM_DRV_CALL_OK:
	port_unlink_ack(prt, try_call_state.state, sulnk);
	finalize_imm_drv_call(&try_call_state);
	BUMP_REDS(c_p, ERTS_PORT_REDS_UNLINK_ACK);
	return ERTS_PORT_OP_DONE;
    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
        port_unlink_ack_failure(prt->common.id, sulnk);
	return ERTS_PORT_OP_DROPPED;
    default:
	/* Schedule call instead... */
	break;
    }

    sigdp = erts_port_task_alloc_p2p_sig_data();
    sigdp->flags = ERTS_P2P_SIG_TYPE_UNLINK_ACK;
    sigdp->u.unlink_ack.port_id = prt->common.id;
    sigdp->u.unlink_ack.sulnk = sulnk;

    return erts_schedule_proc2port_signal(c_p,
					  prt,
					  c_p->common.id,
					  NULL,
					  sigdp,
					  0,
					  NULL,
					  port_sig_unlink_ack);
}

static void
port_link_failure(Port *port, Eterm port_id, ErtsLink *lnk)
{
    erts_proc_sig_send_link_exit(&port->common, port_id, lnk, am_noproc, NIL);
}

static void
port_link(Port *prt, erts_aint32_t state, ErtsLink *nlnk)
{
    if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP) {
        port_link_failure(prt, prt->common.id, nlnk);
    } else {
        ErtsLink *lnk;
        lnk = erts_link_tree_lookup_insert(&ERTS_P_LINKS(prt), nlnk);
        if (lnk)
            erts_link_release(nlnk);
        else if (IS_TRACED_FL(prt, F_TRACE_PORTS))
            trace_port(prt, am_getting_linked, nlnk->other.item);
    }
}

static int
port_sig_link(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
{
    if (op == ERTS_PROC2PORT_SIG_EXEC) {
        port_link(prt, state, sigdp->u.link.lnk);
    } else {
        port_link_failure(prt, sigdp->u.link.port_id, sigdp->u.link.lnk);
    }

    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY) {
        port_sched_op_reply(sigdp->caller, sigdp->ref, am_true, prt);
    }

    return ERTS_PORT_REDS_LINK;
}

ErtsPortOpResult
erts_port_link(Process *c_p, Port *prt, ErtsLink *lnk, Eterm *refp)
{
    ErtsProc2PortSigData *sigdp;
    ErtsTryImmDrvCallState try_call_state
	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(c_p,
					   prt,
					   ERTS_PORT_SFLGS_INVALID_LOOKUP,
					   0,
					   !refp,
					   am_link);

    switch (try_imm_drv_call(&try_call_state)) {
    case ERTS_TRY_IMM_DRV_CALL_OK:
	port_link(prt, try_call_state.state, lnk);
	finalize_imm_drv_call(&try_call_state);
	BUMP_REDS(c_p, ERTS_PORT_REDS_LINK);
	return ERTS_PORT_OP_DONE;
    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
	return ERTS_PORT_OP_BADARG;
    default:
	/* Schedule call instead... */
	break;
    }

    sigdp = erts_port_task_alloc_p2p_sig_data();
    sigdp->flags = ERTS_P2P_SIG_TYPE_LINK;
    sigdp->u.link.port_id = prt->common.id;
    sigdp->u.link.lnk = lnk;
    
    return erts_schedule_proc2port_signal(c_p,
					  prt,
					  c_p->common.id,
					  refp,
					  sigdp,
					  0,
					  NULL,
					  port_sig_link);
}

static void
port_monitor_failure(Port *prt, Eterm port_id, ErtsMonitor *mon)
{
    ASSERT(prt == NULL || prt->common.id == port_id);
    erts_proc_sig_send_monitor_down(prt ? &prt->common : NULL, port_id,
                                    mon, am_noproc);
}

/* Origin wants to monitor port Prt. State contains possible error, which has
 * happened just before. Name is either NIL or an atom, if user monitors
 * a port by name. Ref is premade reference that will be returned to user */
static void
port_monitor(Port *prt, erts_aint32_t state, ErtsMonitor *mon)
{
    ASSERT(prt);

    if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP) {
        port_monitor_failure(prt, prt->common.id, mon);
    } else {
        ASSERT(erts_monitor_is_target(mon));
        erts_monitor_list_insert(&ERTS_P_LT_MONITORS(prt), mon);
    }
}

static int
port_sig_monitor(Port *prt, erts_aint32_t state, int op,
                 ErtsProc2PortSigData *sigdp)
{
    if (op == ERTS_PROC2PORT_SIG_EXEC) {
        port_monitor(prt, state, sigdp->u.monitor.mon);
    } else {
        port_monitor_failure(prt, sigdp->u.monitor.port_id, sigdp->u.monitor.mon);
    }

    return ERTS_PORT_REDS_MONITOR;
}

/* Creates monitor between Origin and Target. Ref must be initialized to
 * a reference (ref may be rewritten to be used to serve additionally as a
 * signal id). Name is atom if user monitors port by name or NIL */
ErtsPortOpResult
erts_port_monitor(Process *c_p, Port *port, ErtsMonitor *mon)
{
    ErtsProc2PortSigData *sigdp;
    ErtsTryImmDrvCallState try_call_state
        = ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
                c_p,
                port,
                ERTS_PORT_SFLGS_INVALID_LOOKUP,
                0,
                !0,
                am_monitor);

    ASSERT(c_p);
    ASSERT(port);
    ASSERT(mon);

    switch (try_imm_drv_call(&try_call_state)) {
    case ERTS_TRY_IMM_DRV_CALL_OK:
        port_monitor(port, try_call_state.state, mon);
        finalize_imm_drv_call(&try_call_state);
        BUMP_REDS(c_p, ERTS_PORT_REDS_MONITOR);
        return ERTS_PORT_OP_DONE;
    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
        return ERTS_PORT_OP_DROPPED;
    default:
        break; /* Schedule call instead... */
    }

    sigdp = erts_port_task_alloc_p2p_sig_data();
    sigdp->flags = ERTS_P2P_SIG_TYPE_MONITOR;
    sigdp->u.monitor.port_id = port->common.id;
    sigdp->u.monitor.mon = mon;

    /* Ref contents will be initialized here */
    return erts_schedule_proc2port_signal(c_p,
                                          port,
                                          c_p->common.id,
                                          NULL,
                                          sigdp,
                                          0,
                                          NULL,
                                          port_sig_monitor);
}

/* Origin wants to demonitor port Prt. State contains possible error, which has
 * happened just before. Ref is reference to monitor */
static void
port_demonitor(Port *port, erts_aint32_t state, ErtsMonitor *mon)
{
    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
    ASSERT(port && mon);
    ASSERT(erts_monitor_is_origin(mon));
    if (!erts_monitor_is_in_table(&mdp->u.target))
        erts_monitor_release(mon);
    else {
        erts_monitor_list_delete(&ERTS_P_LT_MONITORS(port), &mdp->u.target);
        erts_monitor_release_both(mdp);
    }
}

static int
port_sig_demonitor(Port *prt, erts_aint32_t state, int op,
                   ErtsProc2PortSigData *sigdp)
{
    if (op == ERTS_PROC2PORT_SIG_EXEC)
        port_demonitor(prt, state, sigdp->u.demonitor.mon);
    else
        erts_monitor_release(sigdp->u.demonitor.mon);
    return ERTS_PORT_REDS_DEMONITOR;
}

ErtsPortOpResult
erts_port_demonitor(Process *c_p, Port *prt, ErtsMonitor *mon)
{
    ErtsProc2PortSigData *sigdp;
    ErtsTryImmDrvCallState try_call_state
        = ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
                c_p,
                prt, ERTS_PORT_SFLGS_INVALID_LOOKUP,
                0,
                !0,
                am_demonitor);

    ASSERT(c_p && prt && mon);

    switch (try_imm_drv_call(&try_call_state)) {
    case ERTS_TRY_IMM_DRV_CALL_OK:
        port_demonitor(prt, try_call_state.state, mon);
        finalize_imm_drv_call(&try_call_state);
        BUMP_REDS(c_p, ERTS_PORT_REDS_DEMONITOR);
        return ERTS_PORT_OP_DONE;
    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
        return ERTS_PORT_OP_DROPPED;
    default:
        break; /* Schedule call instead... */
    }

    sigdp = erts_port_task_alloc_p2p_sig_data();
    sigdp->flags = ERTS_P2P_SIG_TYPE_DEMONITOR;
    sigdp->u.demonitor.port_id = prt->common.id;
    sigdp->u.demonitor.mon = mon;

    /* Ref contents will be initialized here */
    return erts_schedule_proc2port_signal(c_p, prt, c_p->common.id,
                                          NULL, sigdp, 0, NULL,
                                          port_sig_demonitor);
}


/* Unlink (an internal process) from a port */
static void
unlink_proc(Port *prt, Eterm pid)
{
    ErtsILink *ilnk;

    ASSERT(prt);
    ASSERT(is_internal_pid(pid));

    ilnk = (ErtsILink *) erts_link_tree_lookup(ERTS_P_LINKS(prt),
                                               pid);
    if (ilnk && !ilnk->unlinking) {
        Uint64 id = erts_proc_sig_send_unlink(&prt->common,
                                              prt->common.id,
                                              &ilnk->link);
        if (id != 0)
            ilnk->unlinking = id;
        else {
            erts_link_tree_delete(&ERTS_P_LINKS(prt), &ilnk->link);
            erts_link_internal_release(&ilnk->link);
        }
    }
}

static void
init_ack_send_reply(Port *port, Eterm resp)
{

    if (!is_internal_port(resp))
        unlink_proc(port, port->async_open_port->to);
    port_sched_op_reply(port->async_open_port->to,
                        port->async_open_port->ref,
                        resp,
			port);

    erts_free(ERTS_ALC_T_PRTSD, port->async_open_port);
    port->async_open_port = NULL;
}

void
erl_drv_init_ack(ErlDrvPort ix, ErlDrvData res) {
    Port *port = erts_drvport2port(ix);
    SWord err_type = (SWord)res;
    Eterm resp;

    if (port == ERTS_INVALID_ERL_DRV_PORT && port->async_open_port)
        return;

    if (port->async_open_port) {
        switch(err_type) {
        case -3:
            resp = am_badarg;
            break;
        case -2: {
            char *str = erl_errno_id(errno);
            resp = erts_atom_put((byte *) str, sys_strlen(str),
                                 ERTS_ATOM_ENC_LATIN1, 1);
            break;
        }
        case -1:
            resp = am_einval;
            break;
        default:
            resp = port->common.id;
            break;
        }

        init_ack_send_reply(port, resp);

        if (err_type == -1 || err_type == -2 || err_type == -3)
            driver_failure_term(ix, am_normal, 0);
        port->drv_data = err_type;
    }
}

void
erl_drv_set_os_pid(ErlDrvPort ix, ErlDrvSInt pid) {
    Port *port = erts_drvport2port(ix);

    if (port == ERTS_INVALID_ERL_DRV_PORT)
        return;

    port->os_pid = (SWord)pid;

}

void erts_init_io(int port_tab_size,
		  int port_tab_size_ignore_files,
		  int legacy_port_tab)
{
    ErtsStaticDriver* dp;
    UWord common_element_size;
    erts_rwmtx_opt_t drv_list_rwmtx_opts = ERTS_RWMTX_OPT_DEFAULT_INITER;
    drv_list_rwmtx_opts.type = ERTS_RWMTX_TYPE_EXTREMELY_FREQUENT_READ;
    drv_list_rwmtx_opts.lived = ERTS_RWMTX_LONG_LIVED;

    erts_atomic64_init_nob(&bytes_in, 0);
    erts_atomic64_init_nob(&bytes_out, 0);

    common_element_size = ERTS_ALC_DATA_ALIGN_SIZE(sizeof(Port));
    common_element_size += ERTS_ALC_DATA_ALIGN_SIZE(sizeof(ErtsPortTaskBusyPortQ));
    common_element_size += 10; /* name */
    common_element_size += sizeof(erts_mtx_t);

    init_xports_list_alloc();

    pdl_init();

    if (!port_tab_size_ignore_files) {
	int max_files = sys_max_files();
	if (port_tab_size < max_files)
	    port_tab_size = max_files;
    }

    if (port_tab_size > ERTS_MAX_PORTS)
	port_tab_size = ERTS_MAX_PORTS;
    else if (port_tab_size < ERTS_MIN_PORTS)
	port_tab_size = ERTS_MIN_PORTS;

    erts_rwmtx_init_opt(&erts_driver_list_lock, &drv_list_rwmtx_opts, "driver_list", NIL,
        ERTS_LOCK_FLAGS_PROPERTY_STATIC | ERTS_LOCK_FLAGS_CATEGORY_IO);
    driver_list = NULL;
    erts_tsd_key_create(&driver_list_lock_status_key,
			    "erts_driver_list_lock_status_key");
    erts_tsd_key_create(&driver_list_last_error_key,
			    "erts_driver_list_last_error_key");

    erts_ptab_init_table(&erts_port,
			 ERTS_ALC_T_PORT_TABLE,
			 NULL,
			 (ErtsPTabElementCommon *) &erts_invalid_port.common,
			 port_tab_size,
			 common_element_size, /* Doesn't need to be exact */
			 "port_table",
			 legacy_port_tab,
			 1);

    sys_init_io();

    erts_tsd_set(driver_list_lock_status_key, (void *) 1);
    erts_rwmtx_rwlock(&erts_driver_list_lock);

    init_driver(&fd_driver, &fd_driver_entry, NULL);
    init_driver(&vanilla_driver, &vanilla_driver_entry, NULL);
    init_driver(&spawn_driver, &spawn_driver_entry, NULL);
#ifndef __WIN32__
    init_driver(&forker_driver, &forker_driver_entry, NULL);
#endif
    erts_init_static_drivers();
    for (dp = driver_tab; dp->de != NULL; dp++)
	erts_add_driver_entry(dp->de, NULL, 1, dp->taint);

    erts_tsd_set(driver_list_lock_status_key, NULL);
    erts_rwmtx_rwunlock(&erts_driver_list_lock);
}

#if defined(ERTS_ENABLE_LOCK_COUNT)
static void lcnt_enable_driver_lock_count(erts_driver_t *dp, int enable)
{
    if (dp->lock) {
        if (enable) {
            erts_lcnt_install_new_lock_info(&dp->lock->lcnt, "driver_lock",
                dp->name_atom, ERTS_LOCK_TYPE_MUTEX | ERTS_LOCK_FLAGS_CATEGORY_IO);
        } else {
            erts_lcnt_uninstall(&dp->lock->lcnt);
        }
    }
}

static void lcnt_enable_port_lock_count(Port *prt, int enable)
{
    erts_aint32_t state = erts_atomic32_read_nob(&prt->state);

    if(enable) {
        ErlDrvPDL pdl = prt->port_data_lock;

        erts_lcnt_install_new_lock_info(&prt->sched.mtx.lcnt, "port_sched_lock",
            prt->common.id, ERTS_LOCK_TYPE_MUTEX | ERTS_LOCK_FLAGS_CATEGORY_IO);

        if(pdl) {
            erts_lcnt_install_new_lock_info(&pdl->mtx.lcnt, "port_data_lock",
                prt->common.id, ERTS_LOCK_TYPE_MUTEX | ERTS_LOCK_FLAGS_CATEGORY_IO);
        }

        if(state & ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK) {
            erts_lcnt_install_new_lock_info(&prt->lock->lcnt, "port_lock",
                prt->common.id, ERTS_LOCK_TYPE_MUTEX | ERTS_LOCK_FLAGS_CATEGORY_IO);
        }
    } else {
        erts_lcnt_uninstall(&prt->sched.mtx.lcnt);

        if(prt->port_data_lock) {
            erts_lcnt_uninstall(&prt->port_data_lock->mtx.lcnt);
        }

        if(state & ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK) {
            erts_lcnt_uninstall(&prt->lock->lcnt);
        }
    }
}

void erts_lcnt_update_driver_locks(int enable) {
    erts_driver_t *driver;

    lcnt_enable_driver_lock_count(&vanilla_driver, enable);
    lcnt_enable_driver_lock_count(&spawn_driver, enable);
#ifndef __WIN32__
    lcnt_enable_driver_lock_count(&forker_driver, enable);
#endif
    lcnt_enable_driver_lock_count(&fd_driver, enable);

    erts_rwmtx_rlock(&erts_driver_list_lock);

    for (driver = driver_list; driver; driver = driver->next) {
        lcnt_enable_driver_lock_count(driver, enable);
    }

    erts_rwmtx_runlock(&erts_driver_list_lock);
}

void erts_lcnt_update_port_locks(int enable) {
    int i, max;

    max = erts_ptab_max(&erts_port);

    for(i = 0; i < max; i++) {
        int delay_handle;
        Port *port;

        delay_handle = erts_thr_progress_unmanaged_delay();
        port = erts_pix2port(i);

        if(port != NULL) {
            lcnt_enable_port_lock_count(port, enable);
        }

        if(delay_handle != ERTS_THR_PRGR_DHANDLE_MANAGED) {
            erts_thr_progress_unmanaged_continue(delay_handle);
        }
    }
}

#endif /* defined(ERTS_ENABLE_LOCK_COUNT) */

/*
 * Buffering of data when using line oriented I/O on ports
 */

/* 
 * Buffer states 
 */
#define LINEBUF_MAIN 0
#define LINEBUF_FULL 1
#define LINEBUF_CR_INSIDE 2
#define LINEBUF_CR_AFTER 3

/*
 * Creates a LineBuf to be added to the port structure,
 * Returns: Pointer to a newly allocated and initialized LineBuf.
 * Parameters:
 * bufsiz - The (maximum) size of the line buffer.
 */
LineBuf *allocate_linebuf(bufsiz)
int bufsiz;
{
    int ovsiz = (bufsiz < LINEBUF_INITIAL) ? bufsiz : LINEBUF_INITIAL;
    LineBuf *lb = (LineBuf *) erts_alloc(ERTS_ALC_T_LINEBUF,
					 sizeof(LineBuf)+ovsiz);
    lb->ovsiz = ovsiz;
    lb->bufsiz = bufsiz;
    lb->ovlen = 0;
    lb->data[0] = LINEBUF_MAIN; /* state */
    return lb;
}

/*
 * Initializes a LineBufContext to be used in calls to read_linebuf
 * or flush_linebuf.
 * Returns: 0 if ok, <0 on error.
 * Parameters:
 * lc - Pointer to an allocated LineBufContext.
 * lb - Pointer to a LineBuf structure (probably from the Port structure).
 * buf - A buffer containing the data to be read and split to lines.
 * len - The number of bytes in buf.
 */
static int init_linebuf_context(LineBufContext *lc, LineBuf **lb,
				char *buf, ErlDrvSizeT len)
{
    if(lc == NULL || lb == NULL)
	return -1;
    lc->b = lb;
    lc->buf = buf;
    lc->left = len;
    return 0;
}

static void resize_linebuf(LineBuf **b)
{
    int newsiz = (((*b)->ovsiz * 2) > (*b)->bufsiz) ? (*b)->bufsiz : 
	(*b)->ovsiz * 2;
    *b = (LineBuf *) erts_realloc(ERTS_ALC_T_LINEBUF,
				  (void *) *b,
				  sizeof(LineBuf)+newsiz);
    (*b)->ovsiz = newsiz;
}

/*
 * Delivers all data in the buffer regardless of newlines (always
 * an LINEBUF_NOEOL. Has to be called until it return LINEBUF_EMPTY.
 * Return values and barameters as read_linebuf (see below).
 */
static int flush_linebuf(LineBufContext *bp)
{
    ASSERT(*bp->b != NULL);
    bp->retlen = (*bp->b)->ovlen;
    switch(LINEBUF_STATE(*bp)){
    case LINEBUF_CR_INSIDE:
	if((*bp->b)->ovlen >= (*bp->b)->ovsiz)
	    resize_linebuf(bp->b);
	LINEBUF_DATA(*bp)[((*bp->b)->ovlen)++] = '\r';
	++bp->retlen; /* fall through instead of switching state... */
    case LINEBUF_MAIN:
    case LINEBUF_FULL:
	(*bp->b)->ovlen = 0;
	LINEBUF_STATE(*bp) = LINEBUF_MAIN;
	if(!bp->retlen)
	    return LINEBUF_EMPTY;
	return LINEBUF_NOEOL;
    case LINEBUF_CR_AFTER:
	LINEBUF_STATE(*bp) = LINEBUF_CR_INSIDE;
	(*bp->b)->ovlen = 0;
	if(!bp->retlen)
	    return LINEBUF_EMPTY;
	return LINEBUF_NOEOL;
    default:
	return LINEBUF_ERROR;
    }    
}

/*
 * Reads input from a buffer and "chops" it up in lines.
 * Has to be called repeatedly until it returns LINEBUF_EMPTY
 * to get all lines in buffer.
 * Handles both <LF> and <CR><LF> style newlines.
 * On Unix, this is slightly incorrect, as <CR><LF> is NOT to be regarded
 * as a newline together, but i treat newlines equally in all systems
 * to avoid putting this in sys.c or clutter it with #ifdef's.
 * Returns: LINEBUF_EMPTY if there is no more data that can be
 *   determined as a line (only part of a line left), LINEBUF_EOL if a whole
 *   line could be delivered and LINEBUF_NOEOL if the buffer size has been
 *   exceeded. The data and the data length can be accessed through the 
 *   LINEBUF_DATA and the LINEBUF_DATALEN macros applied to the LineBufContext.
 * Parameters: 
 * bp - A LineBufContext that is initialized with 
 *   the init_linebuf_context call. The context has to be retained during
 *   all calls that returns other than LINEBUF_EMPTY. When LINEBUF_EMPTY
 *   is returned the context can be discarded and a new can be created when new
 *   data arrives (the state is saved in the Port structure).
 */
static int read_linebuf(LineBufContext *bp)
{
    for(;;){
	if(bp->left == 0)
	    return LINEBUF_EMPTY;
	if(*bp->buf == '\n'){
	    LINEBUF_STATE(*bp) = LINEBUF_MAIN;
	    ++(bp->buf);
	    --(bp->left);
	    bp->retlen = (*bp->b)->ovlen;
	    (*bp->b)->ovlen = 0;
	    return LINEBUF_EOL;
	}
	switch(LINEBUF_STATE(*bp)){
	case LINEBUF_MAIN:
	    if((*bp->b)->ovlen == (*bp->b)->bufsiz)
		LINEBUF_STATE(*bp) = LINEBUF_FULL;
	    else if(*bp->buf == '\r'){
		++(bp->buf);
		--(bp->left);
		LINEBUF_STATE(*bp) = LINEBUF_CR_INSIDE;
	    } else {
		if((*bp->b)->ovlen >= (*bp->b)->ovsiz)
		    resize_linebuf(bp->b);
		LINEBUF_DATA(*bp)[((*bp->b)->ovlen)++] = *((bp->buf)++);
		--(bp->left);
	    }
	    continue;
	case LINEBUF_FULL:
	    if(*bp->buf == '\r'){
		++(bp->buf);
		--(bp->left);
		LINEBUF_STATE(*bp) = LINEBUF_CR_AFTER;
	    } else {
		bp->retlen = (*bp->b)->ovlen;
		(*bp->b)->ovlen = 0;
		LINEBUF_STATE(*bp) = LINEBUF_MAIN;
		return LINEBUF_NOEOL;
	    }
	    continue;
	case LINEBUF_CR_INSIDE:
	    if((*bp->b)->ovlen >= (*bp->b)->ovsiz)
		resize_linebuf(bp->b);
	    LINEBUF_DATA(*bp)[((*bp->b)->ovlen)++] = '\r';
	    LINEBUF_STATE(*bp) = LINEBUF_MAIN;
	    continue;
	case LINEBUF_CR_AFTER:
	    bp->retlen = (*bp->b)->ovlen;
	    (*bp->b)->ovlen = 0;
	    LINEBUF_STATE(*bp) = LINEBUF_CR_INSIDE;
	    return LINEBUF_NOEOL;
	default:
	    return LINEBUF_ERROR;
	}
    }
}

static void
deliver_result(Port *prt, Eterm sender, Eterm pid, Eterm res)
{
    Process *rp;
    ErtsProcLocks rp_locks = 0;
    int scheduler = erts_get_scheduler_id() != 0;

    ERTS_CHK_NO_PROC_LOCKS;

    ASSERT(!prt || prt->common.id == sender);
    ERTS_LC_ASSERT(!prt || erts_lc_is_port_locked(prt));

    ASSERT(is_internal_port(sender) && is_internal_pid(pid));

    rp = (scheduler
	  ? erts_proc_lookup(pid)
	  : erts_pid2proc_opt(NULL, 0, pid, 0, ERTS_P2P_FLG_INC_REFC));

    if (prt && IS_TRACED_FL(prt, F_TRACE_SEND)) {
        Eterm hp[3];
        trace_port_send(prt, pid, TUPLE2(hp, sender, res), !!rp);
    }

    if (rp) {
	Eterm tuple;
	ErtsMessage *mp;
	ErlOffHeap *ohp;
	Eterm* hp;
	Uint sz_res;

	sz_res = size_object(res);
	mp = erts_alloc_message_heap(rp, &rp_locks,
				     sz_res + 3, &hp, &ohp);
	res = copy_struct(res, sz_res, &hp, ohp);
	tuple = TUPLE2(hp, sender, res);
	erts_queue_message(rp, rp_locks, mp, tuple, sender);

	if (rp_locks)
	    erts_proc_unlock(rp, rp_locks);
	if (!scheduler)
	    erts_proc_dec_refc(rp);

    }
}


/* 
 * Deliver a "read" message.
 * hbuf -- byte that are always formatted as a list
 * hlen -- number of byte in header
 * buf  -- data 
 * len  -- length of data
 */

static void deliver_read_message(Port* prt, erts_aint32_t state, Eterm to,
				 char *hbuf, ErlDrvSizeT hlen,
				 char *buf, ErlDrvSizeT len, int eol)
{
    ErlDrvSizeT need;
    Eterm listp;
    Eterm tuple;
    Process* rp;
    Eterm* hp;
    ErtsMessage *mp;
    ErlOffHeap *ohp;
    ErtsProcLocks rp_locks = 0;
    int scheduler = erts_get_scheduler_id() != 0;
    int trace_send = IS_TRACED_FL(prt, F_TRACE_SEND);

    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
    ERTS_CHK_NO_PROC_LOCKS;

    need = 3 + 3 + 2*hlen;

    if (state & ERTS_PORT_SFLG_LINEBUF_IO) {
	need += 3;
    }
    if ((state & ERTS_PORT_SFLG_BINARY_IO) && buf != NULL) {
        if (len <= ERL_ONHEAP_BIN_LIMIT)
            need += heap_bin_size(len);
        else
            need += PROC_BIN_SIZE;
    } else {
	need += 2*len;
    }

    rp = (scheduler
	  ? erts_proc_lookup(to)
	  : erts_pid2proc_opt(NULL, 0, to, 0, ERTS_P2P_FLG_INC_REFC));

    if (!rp)
	return;

    mp = erts_alloc_message_heap(trace_send ? NULL : rp, &rp_locks, need, &hp, &ohp);

    listp = NIL;
    if ((state & ERTS_PORT_SFLG_BINARY_IO) == 0) {
	listp = buf_to_intlist(&hp, buf, len, listp);
    } else if (buf != NULL) {
        if (len <= ERL_ONHEAP_BIN_LIMIT) {
            ErlHeapBin *hbin = (ErlHeapBin *) hp;
            hbin->thing_word = header_heap_bin(len);
            hbin->size = (Uint) len;
            sys_memcpy(hbin->data, buf, len);
            listp = make_binary(hp);
            hp += heap_bin_size(len);
        }
        else {
            Binary* bptr = erts_bin_nrml_alloc(len);
            sys_memcpy(bptr->orig_bytes, buf, len);

            listp = erts_build_proc_bin(ohp, hp, bptr);
            hp += PROC_BIN_SIZE;
        }
    }

    /* Prepend the header */
    if (hlen > 0) {
	listp = buf_to_intlist(&hp, hbuf, hlen, listp);
    }

    if (state & ERTS_PORT_SFLG_LINEBUF_IO){
	listp = TUPLE2(hp, (eol) ? am_eol : am_noeol, listp); 
	hp += 3;
    }
    tuple = TUPLE2(hp, am_data, listp);
    hp += 3;

    tuple = TUPLE2(hp, prt->common.id, tuple);
    hp += 3;

    if (trace_send)
        trace_port_send(prt, to, tuple, 1);

    erts_queue_message(rp, rp_locks, mp, tuple, prt->common.id);
    if (rp_locks)
	erts_proc_unlock(rp, rp_locks);
    if (!scheduler)
	erts_proc_dec_refc(rp);
}

/* 
 * Deliver all lines in a line buffer, repeats calls to
 * deliver_read_message, and takes the same parameters.
 */
static void deliver_linebuf_message(Port* prt, erts_aint_t state,
				    Eterm to, 
				    char* hbuf, ErlDrvSizeT hlen,
				    char *buf, ErlDrvSizeT len)
{
    LineBufContext lc;
    int ret;
    if(init_linebuf_context(&lc,&(prt->linebuf), buf, len) < 0)
	return;
    while((ret = read_linebuf(&lc)) > LINEBUF_EMPTY)
	deliver_read_message(prt, state, to, hbuf, hlen, LINEBUF_DATA(lc), 
			     LINEBUF_DATALEN(lc), (ret == LINEBUF_EOL));
}

/*
 * Deliver any nonterminated lines in the line buffer before the
 * port gets closed.
 * Has to be called before terminate_port.
 * Parameters:
 * prt -  Pointer to a Port structure for this port.
 */
static void flush_linebuf_messages(Port *prt, erts_aint32_t state)
{
    LineBufContext lc;
    int ret;

    ERTS_LC_ASSERT(!prt || erts_lc_is_port_locked(prt));

    if (!prt)
	return;

    if (!(state & ERTS_PORT_SFLG_LINEBUF_IO))
	return;

    if(init_linebuf_context(&lc,&(prt->linebuf), NULL, 0) < 0)
	return;
    while((ret = flush_linebuf(&lc)) > LINEBUF_EMPTY)
	deliver_read_message(prt,
			     state,
			     ERTS_PORT_GET_CONNECTED(prt),
			     NULL,
			     0,
			     LINEBUF_DATA(lc), 
			     LINEBUF_DATALEN(lc),
			     (ret == LINEBUF_EOL));
}    

static void
deliver_vec_message(Port* prt,			/* Port */
		    Eterm to,			/* Receiving pid */
		    char* hbuf,			/* "Header" buffer... */
		    ErlDrvSizeT hlen,		/* ... and its length */
		    ErlDrvBinary** binv,	/* Vector of binaries */
		    SysIOVec* iov,		/* I/O vector */
		    int vsize,			/* Size of binv & iov */
		    ErlDrvSizeT csize)		/* Size of characters in
						   iov (not hlen) */
{
    ErlDrvSizeT need;
    Eterm listp;
    Eterm tuple;
    Process* rp;
    Eterm* hp;
    ErtsMessage *mp;
    ErlOffHeap *ohp;
    ErtsProcLocks rp_locks = 0;
    int scheduler = erts_get_scheduler_id() != 0;
    erts_aint32_t state;
    int trace_send = IS_TRACED_FL(prt, F_TRACE_SEND);

    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
    ERTS_CHK_NO_PROC_LOCKS;

    /*
     * Check arguments for validity.
     */


    rp = (scheduler
	  ? erts_proc_lookup(to)
	  : erts_pid2proc_opt(NULL, 0, to, 0, ERTS_P2P_FLG_INC_REFC));
    if (!rp)
	return;

    state = erts_atomic32_read_nob(&prt->state);
    /*
     * Calculate the exact number of heap words needed.
     */

    need = 3 + 3;		/* Heap space for two tuples */
    if (state & ERTS_PORT_SFLG_BINARY_IO) {
        Sint i;
        for (i = 0; i < vsize; i++) {
            if (iov[i].iov_len <= ERL_ONHEAP_BIN_LIMIT)
                need += heap_bin_size(iov[i].iov_len);
            else
                need += PROC_BIN_SIZE;
        }
	need += (vsize - 1)*2 + hlen*2;
    } else {
	need += (hlen+csize)*2;
    }

    mp = erts_alloc_message_heap(trace_send ? NULL : rp, &rp_locks, need, &hp, &ohp);

    listp = NIL;
    iov += vsize;

    if ((state & ERTS_PORT_SFLG_BINARY_IO) == 0) {
	Eterm* thp = hp;
	while (vsize--) {
	    iov--;
	    listp = buf_to_intlist(&thp, iov->iov_base, iov->iov_len, listp);
	}
	hp = thp;
    } else {
	binv += vsize;
	while (vsize--) {
            Eterm bin;
            Uint bin_size;
            iov--;
            binv--;
            bin_size = (Uint) iov->iov_len;
            
            if (bin_size <= ERL_ONHEAP_BIN_LIMIT) {
                ErlHeapBin *hbin = (ErlHeapBin *) hp;
                hbin->thing_word = header_heap_bin(bin_size);
                hbin->size = bin_size;
                sys_memcpy(hbin->data, iov->iov_base, bin_size);
                bin = make_binary(hp);
                hp += heap_bin_size(bin_size);
            }
            else {
                ErlDrvBinary* b;
                ProcBin* pb = (ProcBin*) hp;
                byte* base;

                if ((b = *binv) == NULL) {
                    b = driver_alloc_binary(bin_size);
                    sys_memcpy(b->orig_bytes, iov->iov_base, bin_size);
                    base = (byte*) b->orig_bytes;
                } else {
                    /* Must increment reference count, caller calls free */
                    driver_binary_inc_refc(b);
                    base = iov->iov_base;
                }
                pb->thing_word = HEADER_PROC_BIN;
                pb->size = bin_size;
                pb->next = ohp->first;
                ohp->first = (struct erl_off_heap_header*)pb;
                pb->val = ErlDrvBinary2Binary(b);
                pb->bytes = base;
                pb->flags = 0;
                hp += PROC_BIN_SIZE;
	    
                OH_OVERHEAD(ohp, bin_size / sizeof(Eterm));

                bin = make_binary(pb);
            }

	    if (listp == NIL) {  /* compatible with deliver_bin_message */
		listp = bin;
	    } else {
		listp = CONS(hp, bin, listp);
		hp += 2;
	    }
	}
    }

    if (hlen != 0) {		/* Prepend the header */
	Eterm* thp = hp;
	listp = buf_to_intlist(&thp, hbuf, hlen, listp);
	hp = thp;
    }

    tuple = TUPLE2(hp, am_data, listp);
    hp += 3;
    tuple = TUPLE2(hp, prt->common.id, tuple);
    hp += 3;

    if (IS_TRACED_FL(prt, F_TRACE_SEND))
        trace_port_send(prt, to, tuple, 1);

    erts_queue_message(rp, rp_locks, mp, tuple, prt->common.id);
    erts_proc_unlock(rp, rp_locks);
    if (!scheduler)
	erts_proc_dec_refc(rp);
}


static void deliver_bin_message(Port*  prt,         /* port */
				Eterm to,           /* receiving pid */
				char* hbuf,         /* "header" buffer */
				ErlDrvSizeT hlen,   /* and it's length */
				ErlDrvBinary* bin,  /* binary data */
				ErlDrvSizeT offs,   /* offset into binary */
				ErlDrvSizeT len)    /* length of binary */
{
    SysIOVec vec;

    vec.iov_base = bin->orig_bytes+offs;
    vec.iov_len = len;
    deliver_vec_message(prt, to, hbuf, hlen, &bin, &vec, 1, len);
}

/* flush the port I/O queue and terminate if empty */
/* 
 * Note. 
 *
 * The test for ERTS_PORT_SFLGS_DEAD is important since the
 * driver's  flush function might call driver_async, which when using no
 * threads and being short circuited will notice that the io queue is empty
 * (after calling the driver's async_ready) and recursively call 
 * terminate_port. So when we get back here, the port is already terminated.
 */
static void flush_port(Port *p)
{
    ERTS_CHK_NO_PROC_LOCKS;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(p));

    if (p->drv_ptr->flush != NULL) {
        ERTS_MSACC_PUSH_STATE_M();
#ifdef USE_VM_PROBES
        if (DTRACE_ENABLED(driver_flush)) {
            DTRACE_FORMAT_COMMON_PID_AND_PORT(ERTS_PORT_GET_CONNECTED(p), p)
            DTRACE3(driver_flush, process_str, port_str, p->name);
        }
#endif
#ifdef USE_LTTNG_VM_TRACEPOINTS
        if (LTTNG_ENABLED(driver_flush)) {
            lttng_decl_portbuf(port_str);
            lttng_decl_procbuf(proc_str);
            lttng_pid_to_str(ERTS_PORT_GET_CONNECTED(p), proc_str);
            lttng_port_to_str(p, port_str);
            LTTNG3(driver_flush, proc_str, port_str, p->name);
        }
#endif


        if (IS_TRACED_FL(p, F_TRACE_SCHED_PORTS)) {
	    trace_sched_ports_where(p, am_in, am_flush);
	}
        ERTS_MSACC_SET_STATE_CACHED_M(ERTS_MSACC_STATE_PORT);
	(*p->drv_ptr->flush)((ErlDrvData)p->drv_data);
	ERTS_MSACC_POP_STATE_M();
        if (IS_TRACED_FL(p, F_TRACE_SCHED_PORTS)) {
	    trace_sched_ports_where(p, am_out, am_flush);
	}
	if (p->xports)
	    erts_port_handle_xports(p);
	ASSERT(!p->xports);
    }
    if ((erts_atomic32_read_nob(&p->state) & ERTS_PORT_SFLGS_DEAD) == 0
	&& is_port_ioq_empty(p)) {
	terminate_port(p);
    }
}

/* stop and delete a port that is ERTS_PORT_SFLG_CLOSING */
static void
terminate_port(Port *prt)
{
    Eterm send_closed_port_id;
    Eterm connected_id = NIL /* Initialize to silence compiler */;
    erts_driver_t *drv;
    erts_aint32_t state;
    ErtsPrtSD *psd;

    ERTS_CHK_NO_PROC_LOCKS;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));

    ASSERT(!ERTS_P_LINKS(prt));
    ASSERT(!ERTS_P_MONITORS(prt));
    ASSERT(!ERTS_P_LT_MONITORS(prt));

    /* state may be altered by kill_port() below */
    state = erts_atomic32_read_band_nob(&prt->state,
					~ERTS_PORT_SFLG_SEND_CLOSED);
    if (state & ERTS_PORT_SFLG_SEND_CLOSED) {
	send_closed_port_id = prt->common.id;
	connected_id = ERTS_PORT_GET_CONNECTED(prt);
    }
    else {
	send_closed_port_id = NIL;
    }

    if (ERTS_PTMR_IS_SET(prt))
	erts_cancel_port_timer(prt);

    drv = prt->drv_ptr;
    if (drv->stop != NULL) {
	ERTS_MSACC_PUSH_AND_SET_STATE_M(ERTS_MSACC_STATE_PORT);
#ifdef USE_VM_PROBES
        if (DTRACE_ENABLED(driver_stop)) {
            DTRACE_FORMAT_COMMON_PID_AND_PORT(connected_id, prt)
            DTRACE3(driver_stop, process_str, drv->name, port_str);
        }
#endif
#ifdef USE_LTTNG_VM_TRACEPOINTS
        if (LTTNG_ENABLED(driver_stop)) {
            lttng_decl_portbuf(port_str);
            lttng_decl_procbuf(proc_str);
            lttng_pid_to_str(connected_id, proc_str);
            lttng_port_to_str(prt, port_str);
            LTTNG3(driver_stop, proc_str, port_str, drv->name);
        }
#endif

	(*drv->stop)((ErlDrvData)prt->drv_data);
	ERTS_MSACC_POP_STATE_M();
	if (prt->xports)
	    erts_port_handle_xports(prt);
	ASSERT(!prt->xports);
    }

    if (is_internal_port(send_closed_port_id)
        && IS_TRACED_FL(prt, F_TRACE_SEND))
        trace_port_send(prt, connected_id, am_closed, 1);

    if(drv->handle != NULL) {
	erts_rwmtx_rlock(&erts_driver_list_lock);
	erts_ddll_decrement_port_count(drv->handle); 
	erts_rwmtx_runlock(&erts_driver_list_lock);
    }
    stopq(prt);        /* clear queue memory */
    if(prt->linebuf != NULL){
	erts_free(ERTS_ALC_T_LINEBUF, (void *) prt->linebuf);
	prt->linebuf = NULL;
    }

    erts_cleanup_port_data(prt);

    ASSERT(erts_prtsd_get(prt, ERTS_PRTSD_DIST_ENTRY) == NULL);

    psd = (ErtsPrtSD *) erts_atomic_read_nob(&prt->psd);
    if (psd)
	erts_free(ERTS_ALC_T_PRTSD, psd);

    kill_port(prt);

    /*
     * We don't want to send the closed message until after the
     * port has been removed from the port table (in kill_port()).
     */
    if ((state & ERTS_PORT_SFLG_HALT)
	&& (erts_atomic32_dec_read_nob(&erts_halt_progress) == 0)) {
	erts_port_release(prt); /* We will exit and never return */
	erts_flush_async_exit(erts_halt_code, "");
    }
    if (is_internal_port(send_closed_port_id))
	deliver_result(NULL, send_closed_port_id, connected_id, am_closed);
}

void
erts_terminate_port(Port *pp)
{
    terminate_port(pp);
}

typedef struct {
    Port *port;
    Eterm reason;
} ErtsPortExitContext;

static int link_port_exit(ErtsLink *lnk, void *vpectxt, Sint reds)
{
    ErtsPortExitContext *pectxt = vpectxt;
    Port *port = pectxt->port;

    if (((ErtsILink *) lnk)->unlinking)
        erts_link_release(lnk);
    else
        erts_proc_sig_send_link_exit(&port->common, port->common.id,
                                     lnk, pectxt->reason, NIL);
    return 1;
}

static int monitor_port_exit(ErtsMonitor *mon, void *vpectxt, Sint reds)
{
    ErtsPortExitContext *pectxt = vpectxt;
    Port *port = pectxt->port;

    if (erts_monitor_is_target(mon)) {
        erts_proc_sig_send_monitor_down(&port->common, port->common.id, mon,
                                        pectxt->reason);
    } else {
        erts_proc_sig_send_demonitor(&port->common, port->common.id, 0, mon);
    }

    return 1;
}

/* 'from' is sending 'this_port' an exit signal, (this_port must be internal).
 * If reason is normal we don't do anything, *unless* from is our connected
 * process in which case we close the port. Any other reason kills the port.
 * If 'from' is ourself we always die.
 * When a driver has data in ioq then driver will be set to closing
 * and become inaccessible to the processes. One exception exists and
 * that is to kill a port till reason kill. Then the port is stopped.
 * 
 */

int
erts_deliver_port_exit(Port *prt, Eterm from, Eterm reason, int send_closed,
                       int drop_normal)
{
   ErtsLink *links;
   ErtsMonitor *monitors;
   ErtsMonitor *lt_monitors;
   Eterm modified_reason;
   erts_aint32_t state, set_state_flags;
   ErtsPortExitContext pectxt;

   ERTS_CHK_NO_PROC_LOCKS;
   ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));

   modified_reason = (reason == am_kill) ? am_killed : reason;

#ifdef USE_VM_PROBES
   if (DTRACE_ENABLED(port_exit)) {
       DTRACE_CHARBUF(from_str, DTRACE_TERM_BUF_SIZE);
       DTRACE_CHARBUF(port_str, DTRACE_TERM_BUF_SIZE);
       DTRACE_CHARBUF(reason_str, 64);

       erts_snprintf(from_str, sizeof(DTRACE_CHARBUF_NAME(from_str)), "%T", from);
       dtrace_port_str(prt, port_str);
       erts_snprintf(reason_str, sizeof(DTRACE_CHARBUF_NAME(reason_str)), "%T",
                     modified_reason);
       DTRACE4(port_exit, from_str, port_str, prt->name, reason_str);
   }
#endif

   state = erts_atomic32_read_nob(&prt->state);
   if (state & (ERTS_PORT_SFLGS_DEAD
		| ERTS_PORT_SFLG_EXITING
		| ERTS_PORT_SFLG_CLOSING))
       return 0;

   if (reason == am_normal && from != ERTS_PORT_GET_CONNECTED(prt)
       && from != prt->common.id && drop_normal) {
       return 0;
   }

   set_state_flags = ERTS_PORT_SFLG_EXITING;
   if (send_closed)
       set_state_flags |= ERTS_PORT_SFLG_SEND_CLOSED;

   erts_port_task_sched_enter_exiting_state(&prt->sched);
   
   state = erts_atomic32_read_bor_mb(&prt->state, set_state_flags);
   state |= set_state_flags;

   if (IS_TRACED_FL(prt, F_TRACE_PORTS))
        trace_port(prt, am_closed, reason);

   erts_trace_check_exiting(prt->common.id);

   set_busy_port(ERTS_Port2ErlDrvPort(prt), 0);

   links = ERTS_P_LINKS(prt);
   ERTS_P_LINKS(prt) = NULL;
   monitors = ERTS_P_MONITORS(prt);
   ERTS_P_MONITORS(prt) = NULL;
   lt_monitors = ERTS_P_LT_MONITORS(prt);
   ERTS_P_LT_MONITORS(prt) = NULL;

   if (prt->common.u.alive.reg != NULL)
       (void) erts_unregister_name(NULL, 0, prt, prt->common.u.alive.reg->name);

   pectxt.reason = modified_reason;
   pectxt.port = prt;

   if (state & ERTS_PORT_SFLG_DISTRIBUTION) {
       DistEntry *dep = (DistEntry*) erts_prtsd_get(prt, ERTS_PRTSD_DIST_ENTRY);
       ASSERT(dep);
       erts_do_net_exits(dep, modified_reason);
       erts_deref_dist_entry(dep);
       erts_prtsd_set(prt, ERTS_PRTSD_DIST_ENTRY, NULL);
       erts_atomic32_read_band_relb(&prt->state,
				    ~ERTS_PORT_SFLG_DISTRIBUTION);
   }
   
   if (links)
       erts_monitor_tree_foreach_delete(&links,
                                        link_port_exit,
                                        (void *) &pectxt);

   if (monitors || lt_monitors) {
       DRV_MONITOR_LOCK_PDL(prt);
       if (monitors)
           erts_monitor_tree_foreach_delete(&monitors,
                                            monitor_port_exit,
                                            (void *) &pectxt);
       if (lt_monitors)
           erts_monitor_list_foreach_delete(&lt_monitors,
                                            monitor_port_exit,
                                            (void *) &pectxt);
       DRV_MONITOR_UNLOCK_PDL(prt);
   }
       
   if ((reason != am_kill) && !is_port_ioq_empty(prt)) {
       /* must turn exiting flag off */
       erts_atomic32_read_bset_relb(&prt->state,
				    (ERTS_PORT_SFLG_EXITING
				     | ERTS_PORT_SFLG_CLOSING),
				    ERTS_PORT_SFLG_CLOSING);
      flush_port(prt);
   }
   else {
       terminate_port(prt);
   }

   return 1;
}

/* About the states ERTS_PORT_SFLG_EXITING and ERTS_PORT_SFLG_CLOSING used above.
**
** ERTS_PORT_SFLG_EXITING is a recursion protection for erts_deliver_port_exit().
** It is unclear  whether this state is necessary or not, it might be possible
** to merge it with ERTS_PORT_SFLG_CLOSING. ERTS_PORT_SFLG_EXITING only persists
** over a section of sequential (but highly recursive) code.
**
** ERTS_PORT_SFLG_CLOSING is a state where the port is in Limbo, waiting to
** pass on. All links are removed, and the port receives in/out-put events so
** as soon as the port queue gets empty terminate_port() is called.
*/



/* Command should be of the form
**   {PID, close}
**   {PID, {command, io-list}}
**   {PID, {connect, New_PID}}
*/
ErtsPortOpResult
erts_port_command(Process *c_p,
		  int flags,
		  Port *port,
		  Eterm command,
		  Eterm *refp)
{
    Eterm *tp;

    ASSERT(port);

    flags |= ERTS_PORT_SIG_FLG_BANG_OP;
    if (!erts_port_synchronous_ops) {
	flags |= ERTS_PORT_SIG_FLG_ASYNC;
	refp = NULL;
    }

    if (is_tuple_arity(command, 2)) {
	Eterm cntd;
	tp = tuple_val(command);
	cntd = tp[1];
	if (is_internal_pid(cntd)) {
	    if (tp[2] == am_close) {
		flags &= ~ERTS_PORT_SIG_FLG_NOSUSPEND;
		return erts_port_exit(c_p, flags, port, cntd, am_normal, refp);
	    } else if (is_tuple_arity(tp[2], 2)) {
		tp = tuple_val(tp[2]);
		if (tp[1] == am_command) {
		    return erts_port_output(c_p, flags, port, cntd, tp[2], refp);
		}
		else if (tp[1] == am_connect) {
		    flags &= ~ERTS_PORT_SIG_FLG_NOSUSPEND;
		    return erts_port_connect(c_p, flags, port, cntd, tp[2], refp);
		}
	    }
	}
    }

    /* badsig */
    flags &= ~ERTS_PORT_SIG_FLG_NOSUSPEND;
    return bad_port_signal(c_p, flags, port, c_p->common.id, refp, am_command);
}

static ERTS_INLINE ErtsPortOpResult
call_driver_control(Eterm caller,
		    Port *prt,
		    unsigned int command,
		    char *bufp,
		    ErlDrvSizeT size,
		    char **resp_bufp,
		    ErlDrvSizeT *from_size)
{
    ErlDrvSSizeT cres;
    ERTS_MSACC_PUSH_STATE_M();

    if (!prt->drv_ptr->control)
	return ERTS_PORT_OP_BADARG;


#ifdef USE_VM_PROBES
    if (DTRACE_ENABLED(port_control) || DTRACE_ENABLED(driver_control)) {
        DTRACE_FORMAT_COMMON_PID_AND_PORT(caller, prt);
        DTRACE4(port_control, process_str, port_str, prt->name, command);
        DTRACE5(driver_control, process_str, port_str, prt->name,
                command, size);
    }
#endif

    if (IS_TRACED_FL(prt, F_TRACE_RECEIVE))
        trace_port_receive(prt, caller, am_control, command, bufp, size);

    ERTS_MSACC_SET_STATE_CACHED_M(ERTS_MSACC_STATE_PORT);

#ifdef USE_LTTNG_VM_TRACEPOINTS
    if (LTTNG_ENABLED(driver_control)) {
        lttng_decl_procbuf(proc_str);
        lttng_decl_portbuf(port_str);
        lttng_pid_to_str(caller, proc_str);
        lttng_port_to_str(prt, port_str);
        LTTNG5(driver_control, proc_str, port_str, prt->name, command, size);
    }
#endif

    prt->caller = caller;
    cres = prt->drv_ptr->control((ErlDrvData) prt->drv_data,
				 command,
				 bufp,
				 size,
				 resp_bufp,
				 *from_size);
    prt->caller = NIL;

    ERTS_MSACC_POP_STATE_M();

    if (cres < 0)
	return ERTS_PORT_OP_BADARG;

    if (IS_TRACED_FL(prt, F_TRACE_SEND))
        trace_port_send_binary(prt, caller, am_control, *resp_bufp, cres);

    *from_size = (ErlDrvSizeT) cres;

    return ERTS_PORT_OP_DONE;
}

static void
cleanup_scheduled_control(Binary *binp, char *bufp)
{
    if (binp) {
        erts_bin_release(binp);
    }
    else {
	if (bufp)
	    erts_free(ERTS_ALC_T_DRV_CTRL_DATA, bufp);
    }
}


static ERTS_INLINE Uint
port_control_result_size(int control_flags,
			 char *resp_bufp,
			 ErlDrvSizeT *resp_size,
			 char *pre_alloc_buf)
{
    if (!resp_bufp)
	return (Uint) 0;

    if (control_flags & PORT_CONTROL_FLAG_BINARY) {
	if (resp_bufp != pre_alloc_buf) {
	    ErlDrvBinary *dbin = (ErlDrvBinary *) resp_bufp;
	    *resp_size = dbin->orig_size;
	    if (*resp_size > ERL_ONHEAP_BIN_LIMIT)
		return PROC_BIN_SIZE;
	}
	ASSERT(*resp_size <= ERL_ONHEAP_BIN_LIMIT);
	return (Uint) heap_bin_size((*resp_size));
    }

    return (Uint) 2*(*resp_size);
}

static ERTS_INLINE Eterm
write_port_control_result(int control_flags,
			  char *resp_bufp,
			  ErlDrvSizeT resp_size,
			  char *pre_alloc_buf,
			  Eterm **hpp,
			  ErlOffHeap *ohp)
{
    Eterm res;
    if (!resp_bufp)
	return NIL;
    if (control_flags & PORT_CONTROL_FLAG_BINARY) {
	/* Binary result */
	ErlDrvBinary *dbin;
	ErlHeapBin *hbin;

	if (resp_bufp == pre_alloc_buf)
	    dbin = NULL;
	else {
	    dbin = (ErlDrvBinary *) resp_bufp;
	    if (dbin->orig_size > ERL_ONHEAP_BIN_LIMIT) {
                res = erts_build_proc_bin(ohp, *hpp, ErlDrvBinary2Binary(dbin));
		*hpp += PROC_BIN_SIZE;
                return res;
	    }
	    resp_bufp = dbin->orig_bytes;
	    resp_size = dbin->orig_size;
	}

	hbin = (ErlHeapBin *) *hpp;
	*hpp += heap_bin_size(resp_size);
	ASSERT(resp_size <= ERL_ONHEAP_BIN_LIMIT);
	hbin->thing_word = header_heap_bin(resp_size);
	hbin->size = resp_size;
	sys_memcpy(hbin->data, resp_bufp, resp_size);
	if (dbin)
	    driver_free_binary(dbin);
	return make_binary(hbin);
    }

    /* List result */
    res = buf_to_intlist(hpp, resp_bufp, resp_size, NIL);
    if (resp_bufp != pre_alloc_buf)
	driver_free(resp_bufp);
    return res;
}

static int
port_sig_control(Port *prt,
		 erts_aint32_t state,
		 int op,
		 ErtsProc2PortSigData *sigdp)
{
    ASSERT(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY);

    if (op == ERTS_PROC2PORT_SIG_EXEC) {
	char resp_buf[ERL_ONHEAP_BIN_LIMIT];
	ErlDrvSizeT resp_size = sizeof(resp_buf);
	char *resp_bufp = &resp_buf[0];
	ErtsPortOpResult res;

	res = call_driver_control(sigdp->caller,
				  prt,
				  sigdp->u.control.command,
				  sigdp->u.control.bufp,
				  sigdp->u.control.size,
				  &resp_bufp,
				  &resp_size);

	if (res == ERTS_PORT_OP_DONE) {
	    Eterm msg;
            ErtsHeapFactory factory;
	    Process *rp;
	    ErtsProcLocks rp_locks = 0;
	    Uint hsz, rsz;
	    int control_flags;

	    rp = sigdp->caller == ERTS_INVALID_PID ? NULL : erts_proc_lookup_raw(sigdp->caller);
	    if (!rp)
		goto done;

	    control_flags = prt->control_flags;

	    rsz = port_control_result_size(control_flags,
					    resp_bufp,
					    &resp_size,
					    &resp_buf[0]);
	    hsz = rsz + ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE;


	    (void) erts_factory_message_create(&factory, rp,
					       &rp_locks, hsz);

	    msg = write_port_control_result(control_flags,
					    resp_bufp,
					    resp_size,
					    &resp_buf[0],
					    &factory.hp,
					    factory.off_heap);
	    queue_port_sched_op_reply(rp,
				      rp_locks,
                                      &factory,
				      sigdp->ref,
				      msg,
				      prt);

	    if (rp_locks)
		erts_proc_unlock(rp, rp_locks);
	    goto done;
	}
    }

    /* failure */

    if (sigdp->caller != ERTS_INVALID_PID)
        port_sched_op_reply(sigdp->caller, sigdp->ref, am_badarg, prt);

done:

    cleanup_scheduled_control(sigdp->u.control.binp,
			      sigdp->u.control.bufp);

    return ERTS_PORT_REDS_CONTROL;
}

/*
 * This is an asynchronous control call. I.e. it will not return anything
 * to the caller.
 */
int
erl_drv_port_control(Eterm port_num, unsigned int cmd, char* buff, ErlDrvSizeT size)
{
    ErtsProc2PortSigData *sigdp = erts_port_task_alloc_p2p_sig_data();

    sigdp->flags = ERTS_P2P_SIG_TYPE_CONTROL | ERTS_P2P_SIG_DATA_FLG_REPLY;
    sigdp->u.control.binp = NULL;
    sigdp->u.control.command = cmd;
    sigdp->u.control.bufp = buff;
    sigdp->u.control.size = size;

    return erts_schedule_port2port_signal(port_num, sigdp, 0, port_sig_control);
}

ErtsPortOpResult
erts_port_control(Process* c_p,
		  Port *prt,
		  unsigned int command,
		  Eterm data,
		  Eterm *retvalp)
{
    ErtsPortOpResult res;
    char *bufp = NULL;
    ErlDrvSizeT size = 0;
    int try_call;
    int tmp_alloced = 0;
    erts_aint32_t sched_flags;
    Binary *binp;
    int copy;
    ErtsProc2PortSigData *sigdp;

    sched_flags = erts_atomic32_read_nob(&prt->sched.flags);
    if (sched_flags & ERTS_PTS_FLG_EXIT)
	return ERTS_PORT_OP_BADARG;

    try_call = !(sched_flags & ERTS_PTS_FLGS_FORCE_SCHEDULE_OP);

    if (is_binary(data) && binary_bitoffset(data) == 0) {
	byte *bytep;
	ERTS_DECLARE_DUMMY(Uint bitoffs);
	ERTS_DECLARE_DUMMY(Uint bitsize);
	ERTS_GET_BINARY_BYTES(data, bytep, bitoffs, bitsize);
	bufp = (char *) bytep;
	size = binary_size(data);
    } else {
	int r;

	if (!try_call) {
	    if (erts_iolist_size(data, &size))
		return ERTS_PORT_OP_BADARG;
	    bufp = erts_alloc(ERTS_ALC_T_DRV_CTRL_DATA, size);
	    r = erts_iolist_to_buf(data, bufp, size);
	    ASSERT(r == 0);
	}
	else {
	    /* Try with an 8KB buffer first (will often be enough I guess). */
	    size = 8*1024;
	    bufp = erts_alloc(ERTS_ALC_T_TMP, size);
	    tmp_alloced = 1;

	    r = erts_iolist_to_buf(data, bufp, size);
	    if (ERTS_IOLIST_TO_BUF_SUCCEEDED(r)) {
		size -= r;
	    } else {
		if (r == ERTS_IOLIST_TO_BUF_TYPE_ERROR) { /* Type error */
		    erts_free(ERTS_ALC_T_TMP, bufp);
		    return ERTS_PORT_OP_BADARG;
		}
		else {
		    ASSERT(r == ERTS_IOLIST_TO_BUF_OVERFLOW); /* Overflow */
		    erts_free(ERTS_ALC_T_TMP, bufp);
		    if (erts_iolist_size(data, &size))
			return ERTS_PORT_OP_BADARG; /* Type error */
		}
		bufp = erts_alloc(ERTS_ALC_T_TMP, size);
		r = erts_iolist_to_buf(data, bufp, size);
		ASSERT(r == 0);
	    }
	}
    }

    if (try_call) {
	char resp_buf[ERL_ONHEAP_BIN_LIMIT];
	char* resp_bufp = &resp_buf[0];
	ErlDrvSizeT resp_size = sizeof(resp_buf);
	ErtsTryImmDrvCallResult try_call_res;
	ErtsTryImmDrvCallState try_call_state
	    = ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
		c_p,
		prt,
		ERTS_PORT_SFLGS_INVALID_LOOKUP,
		0,
		0,
		am_control);

	try_call_res = try_imm_drv_call(&try_call_state);
	switch (try_call_res) {
	case ERTS_TRY_IMM_DRV_CALL_OK: {
	    Eterm *hp;
	    Uint hsz;
	    int control_flags;

	    res = call_driver_control(c_p->common.id,
				      prt,
				      command,
				      bufp,
				      size,
				      &resp_bufp,
				      &resp_size);

	    control_flags = prt->control_flags;

	    finalize_imm_drv_call(&try_call_state);
	    if (tmp_alloced)
		erts_free(ERTS_ALC_T_TMP, bufp);
	    if (res == ERTS_PORT_OP_BADARG) {
		return ERTS_PORT_OP_BADARG;
	    }

	    hsz = port_control_result_size(control_flags,
					   resp_bufp,
					   &resp_size,
					   &resp_buf[0]);
	    hp = HAlloc(c_p, hsz);
	    *retvalp = write_port_control_result(control_flags,
						 resp_bufp,
						 resp_size,
						 &resp_buf[0],
						 &hp,
						 &c_p->off_heap);
	    BUMP_REDS(c_p, ERTS_PORT_REDS_CONTROL);
	    return ERTS_PORT_OP_DONE;
	}
	case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
	    if (tmp_alloced)
		erts_free(ERTS_ALC_T_TMP, bufp);
	    return ERTS_PORT_OP_BADARG;
	default:
	    /* Schedule control() call instead... */
	    break;
	}
    }

    /* Convert data into something that can be scheduled */

    copy = tmp_alloced;

    binp = NULL;

    if (is_binary(data) && binary_bitoffset(data) == 0) {
	Eterm *ebinp = binary_val(data);
	ASSERT(!tmp_alloced);
	if (*ebinp == HEADER_SUB_BIN)
	    ebinp = binary_val(((ErlSubBin *) ebinp)->orig);

	if (*ebinp != HEADER_PROC_BIN)
	    copy = 1;
	else {
            ProcBin *pb = (ProcBin *) ebinp;
            int offset = bufp - pb->val->orig_bytes;

	    ASSERT(pb->val->orig_bytes <= bufp
		   && bufp + size <= pb->val->orig_bytes + pb->val->orig_size);

            if (pb->flags) {
                erts_emasculate_writable_binary(pb);

                /* The procbin may have been reallocated, so update bufp */
                bufp = pb->val->orig_bytes + offset;
            }

	    binp = pb->val;
	    ASSERT(bufp <= bufp + size);
	    ASSERT(binp->orig_bytes <= bufp
		   && bufp + size <= binp->orig_bytes + binp->orig_size);
	    erts_refc_inc(&binp->intern.refc, 1);
	}
    }

    if (copy) {
	char *old_bufp = bufp;
	bufp = erts_alloc(ERTS_ALC_T_DRV_CTRL_DATA, size);
	sys_memcpy(bufp, old_bufp, size);
	if (tmp_alloced)
	    erts_free(ERTS_ALC_T_TMP, old_bufp);
    }

    sigdp = erts_port_task_alloc_p2p_sig_data();
    sigdp->flags = ERTS_P2P_SIG_TYPE_CONTROL;
    sigdp->u.control.binp = binp;
    sigdp->u.control.command = command;
    sigdp->u.control.bufp = bufp;
    sigdp->u.control.size = size;
    
    res = erts_schedule_proc2port_signal(c_p,
					 prt,
					 c_p->common.id,
					 retvalp,
					 sigdp,
					 0,
					 NULL,
					 port_sig_control);
    if (res != ERTS_PORT_OP_SCHEDULED)
	return ERTS_PORT_OP_BADARG;

    return res;
}

static ERTS_INLINE ErtsPortOpResult
call_driver_call(Eterm caller,
		 Port *prt,
		 unsigned int command,
		 char *bufp,
		 ErlDrvSizeT size,
		 char **resp_bufp,
		 ErlDrvSizeT *from_size,
		 unsigned *ret_flagsp)
{
    ErlDrvSSizeT cres;
    ERTS_MSACC_PUSH_STATE_M();

    if (!prt->drv_ptr->call)
	return ERTS_PORT_OP_BADARG;

#ifdef USE_VM_PROBES
    if (DTRACE_ENABLED(driver_call)) {
        DTRACE_CHARBUF(process_str, DTRACE_TERM_BUF_SIZE);
        DTRACE_CHARBUF(port_str, DTRACE_TERM_BUF_SIZE);

        dtrace_pid_str(caller, process_str);
        dtrace_port_str(prt, port_str);
        DTRACE5(driver_call, process_str, port_str, prt->name, command, size);
    }
#endif
#ifdef USE_LTTNG_VM_TRACEPOINTS
    if (LTTNG_ENABLED(driver_call)) {
        lttng_decl_procbuf(proc_str);
        lttng_decl_portbuf(port_str);
        lttng_pid_to_str(caller,proc_str);
        lttng_port_to_str(prt, port_str);
        LTTNG5(driver_call, proc_str, port_str, prt->name, command, size);
    }
#endif

    if (IS_TRACED_FL(prt, F_TRACE_RECEIVE))
        trace_port_receive(prt, caller, am_call, command, bufp, size);

    ERTS_MSACC_SET_STATE_CACHED_M(ERTS_MSACC_STATE_PORT);

    prt->caller = caller;
    cres = prt->drv_ptr->call((ErlDrvData) prt->drv_data,
			      command,
			      bufp,
			      size,
			      resp_bufp,
			      *from_size,
			      ret_flagsp);
    prt->caller = NIL;

    ERTS_MSACC_POP_STATE_M();

    if (cres <= 0
	|| ((byte) (*resp_bufp)[0]) != VERSION_MAGIC)
	return ERTS_PORT_OP_BADARG;

    if (IS_TRACED_FL(prt, F_TRACE_SEND))
        trace_port_send_binary(prt, caller, am_call, *resp_bufp, cres);

    *from_size = (ErlDrvSizeT) cres;

    return ERTS_PORT_OP_DONE;
}


static
void cleanup_scheduled_call(char *bufp)
{
    if (bufp)
	erts_free(ERTS_ALC_T_DRV_CALL_DATA, bufp);
}

static int
port_sig_call(Port *prt,
	      erts_aint32_t state,
	      int op,
	      ErtsProc2PortSigData *sigdp)
{
    char resp_buf[256];
    ErlDrvSizeT resp_size = sizeof(resp_buf);
    char *resp_bufp = &resp_buf[0];
    unsigned ret_flags = 0U;


    ASSERT(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY);

    if (op == ERTS_PROC2PORT_SIG_EXEC) {
	ErtsPortOpResult res;

	res = call_driver_call(sigdp->caller,
			       prt,
			       sigdp->u.call.command,
			       sigdp->u.call.bufp,
			       sigdp->u.call.size,
			       &resp_bufp,
			       &resp_size,
			       &ret_flags);

	if (res == ERTS_PORT_OP_DONE) {
	    Eterm msg;
	    Eterm *hp;
	    Process *rp;
	    ErtsProcLocks rp_locks = 0;
	    Sint hsz;

	    rp = erts_proc_lookup_raw(sigdp->caller);
	    if (!rp)
		goto done;

	    hsz = erts_decode_ext_size((byte *) resp_bufp, resp_size);
	    if (hsz >= 0) {
                ErtsHeapFactory factory;
		byte *endp;

		hsz += 3; /* ok tuple */
		hsz += ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE;

                (void) erts_factory_message_create(&factory, rp, &rp_locks, hsz);
		endp = (byte *) resp_bufp;
		msg = erts_decode_ext(&factory, (const byte**)&endp, 0);
		if (is_value(msg)) {
                    hp = erts_produce_heap(&factory,
                                           3,
                                           ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE);
		    msg = TUPLE2(hp, am_ok, msg);

		    queue_port_sched_op_reply(rp,
					      rp_locks,
                                              &factory,
					      sigdp->ref,
					      msg,
					      prt);

		    if (rp_locks)
			erts_proc_unlock(rp, rp_locks);
		    goto done;
		}
		if (rp_locks)
		    erts_proc_unlock(rp, rp_locks);
	    }
	}
    }

    port_sched_op_reply(sigdp->caller, sigdp->ref, am_badarg, prt);

done:

    if (resp_bufp != &resp_buf[0] && !(ret_flags & DRIVER_CALL_KEEP_BUFFER))
	driver_free(resp_bufp);

    cleanup_scheduled_call(sigdp->u.call.bufp);

    return ERTS_PORT_REDS_CALL;
}


ErtsPortOpResult
erts_port_call(Process* c_p,
	       Port *prt,
	       unsigned int command,
	       Eterm data,
	       Eterm *retvalp)
{
    ErtsPortOpResult res;
    char input_buf[256];
    char *bufp;
    byte *endp;
    Uint uintsz;
    ErlDrvSizeT size;
    int try_call;
    erts_aint32_t sched_flags;
    ErtsProc2PortSigData *sigdp;

    sched_flags = erts_atomic32_read_nob(&prt->sched.flags);
    if (sched_flags & ERTS_PTS_FLG_EXIT) {
	return ERTS_PORT_OP_BADARG;
    }

    try_call = !(sched_flags & ERTS_PTS_FLGS_FORCE_SCHEDULE_OP);

    if (erts_encode_ext_size(data, &uintsz) != ERTS_EXT_SZ_OK)
        return ERTS_PORT_OP_BADARG;
    size = (ErlDrvSizeT) uintsz;

    if (!try_call)
	bufp = erts_alloc(ERTS_ALC_T_DRV_CALL_DATA, size);
    else if (size <= sizeof(input_buf))
	bufp = &input_buf[0];
    else
	bufp = erts_alloc(ERTS_ALC_T_TMP, size);

    endp = (byte *) bufp;
    erts_encode_ext(data, &endp);

    if (endp - (byte *) bufp > size)
	ERTS_INTERNAL_ERROR("erts_internal:port_call() - Buffer overflow");

    size = endp - (byte *) bufp;

    if (try_call) {
	char resp_buf[255];
	char* resp_bufp = &resp_buf[0];
	ErlDrvSizeT resp_size = sizeof(resp_buf);
	ErtsTryImmDrvCallResult try_call_res;
	ErtsTryImmDrvCallState try_call_state
	    = ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
		c_p,
		prt,
		ERTS_PORT_SFLGS_INVALID_LOOKUP,
		0,
		0,
		am_call);

	try_call_res = try_imm_drv_call(&try_call_state);
	switch (try_call_res) {
	case ERTS_TRY_IMM_DRV_CALL_OK: {
            ErtsHeapFactory factory;
	    Sint hsz;
	    unsigned ret_flags = 0U;
	    Eterm term;
            Eterm* hp;

	    res = call_driver_call(c_p->common.id,
				   prt,
				   command,
				   bufp,
				   size,
				   &resp_bufp,
				   &resp_size,
				   &ret_flags);

	    finalize_imm_drv_call(&try_call_state);
	    if (bufp != &input_buf[0])
		erts_free(ERTS_ALC_T_TMP, bufp);
	    if (res == ERTS_PORT_OP_BADARG)
		return ERTS_PORT_OP_BADARG;
	    hsz = erts_decode_ext_size((byte *) resp_bufp, resp_size);
	    if (hsz < 0)
		return ERTS_PORT_OP_BADARG;
	    hsz += 3;
            erts_factory_proc_prealloc_init(&factory, c_p, hsz);
	    endp = (byte *) resp_bufp;
	    term = erts_decode_ext(&factory, (const byte**)&endp, 0);
	    if (term == THE_NON_VALUE)
		return ERTS_PORT_OP_BADARG;
            hp = erts_produce_heap(&factory,3,0);
	    *retvalp = TUPLE2(hp, am_ok, term);
            erts_factory_close(&factory);
	    if (resp_bufp != &resp_buf[0]
		&& !(ret_flags & DRIVER_CALL_KEEP_BUFFER))
		driver_free(resp_bufp);
	    BUMP_REDS(c_p, ERTS_PORT_REDS_CALL);
	    return ERTS_PORT_OP_DONE;
	}
	case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
	    if (bufp != &input_buf[0])
		erts_free(ERTS_ALC_T_TMP, bufp);
	    return ERTS_PORT_OP_BADARG;
	default:
	    /* Schedule call() call instead... */
	    break;
	}
    }

    /* Convert data into something that can be scheduled */

    if (bufp == &input_buf[0] || try_call) {
	char *new_bufp = erts_alloc(ERTS_ALC_T_DRV_CALL_DATA, size);
	sys_memcpy(new_bufp, bufp, size);
	if (bufp != &input_buf[0])
	    erts_free(ERTS_ALC_T_TMP, bufp);
	bufp = new_bufp;
    }

    sigdp = erts_port_task_alloc_p2p_sig_data();
    sigdp->flags = ERTS_P2P_SIG_TYPE_CALL;
    sigdp->u.call.command = command;
    sigdp->u.call.bufp = bufp;
    sigdp->u.call.size = size;
    
    res = erts_schedule_proc2port_signal(c_p,
					 prt,
					 c_p->common.id,
					 retvalp,
					 sigdp,
					 0,
					 NULL,
					 port_sig_call);
    if (res != ERTS_PORT_OP_SCHEDULED)
	return ERTS_PORT_OP_BADARG;

    return res;
}

static Eterm
make_port_info_term(Eterm **hpp_start,
		    Eterm **hpp,
		    Uint *hszp,
		    ErlHeapFragment **bpp,
		    Port *prt,
		    Eterm item)
{
    ErlOffHeap *ohp;

    if (is_value(item)) {
	if (erts_bld_port_info(NULL, NULL, hszp, prt, item) == am_false)
	    return THE_NON_VALUE;
	if (*hszp) {
	    *bpp = new_message_buffer(*hszp);
	    *hpp_start = *hpp = (*bpp)->mem;
	    ohp = &(*bpp)->off_heap;
	}
	else {
	    *bpp = NULL;
	    *hpp_start = *hpp = NULL;
	    ohp = NULL;
	}
	return erts_bld_port_info(hpp, ohp, NULL, prt, item);
    }
    else {
	int i;
	int len;
	int start;
	static Eterm item[] = ERTS_PORT_INFO_1_ITEMS;
        Eterm value[sizeof(item)/sizeof(item[0])];

	start = 0;
	len = sizeof(item)/sizeof(item[0]);

	for (i = start; i < sizeof(item)/sizeof(item[0]); i++) {
	    ASSERT(is_atom(item[i]));
	    value[i] = erts_bld_port_info(NULL, NULL, hszp, prt, item[i]);
	}

	if (value[0] == am_undefined) {
	    start++;
	    len--;
	}

	erts_bld_list(NULL, hszp, len, &value[start]);

	*bpp = new_message_buffer(*hszp);
	*hpp_start = *hpp = (*bpp)->mem;
	ohp = &(*bpp)->off_heap;

	for (i = start; i < sizeof(item)/sizeof(item[0]); i++)
	    value[i] = erts_bld_port_info(hpp, ohp, NULL, prt, item[i]);

	return erts_bld_list(hpp, NULL, len, &value[start]);
    }
}

static int
port_sig_info(Port *prt,
	      erts_aint32_t state,
	      int op,
	      ErtsProc2PortSigData *sigdp)
{
    ASSERT(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY);
    if (op != ERTS_PROC2PORT_SIG_EXEC)
	port_sched_op_reply(sigdp->caller, sigdp->ref, am_undefined, prt);
    else {
	Eterm *hp, *hp_start;
	Uint hsz;
	ErlHeapFragment *bp;
	Eterm value;
	Process *rp;
	ErtsProcLocks rp_locks = 0;

	rp = erts_proc_lookup_raw(sigdp->caller);
	if (!rp)
	    return ERTS_PORT_REDS_INFO;

	hsz = ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE;
	value = make_port_info_term(&hp_start,
				    &hp,
				    &hsz,
				    &bp,
				    prt,
				    sigdp->u.info.item);
	if (is_value(value)) {
            ErtsHeapFactory factory;
	    ErtsMessage *mp = erts_alloc_message(0, NULL);
	    mp->data.heap_frag = bp;
            erts_factory_selfcontained_message_init(&factory, mp, hp);
	    queue_port_sched_op_reply(rp,
				      rp_locks,
                                      &factory,
				      sigdp->ref,
				      value,
				      prt);
	}
	if (rp_locks)
	    erts_proc_unlock(rp, rp_locks);
    }
    return ERTS_PORT_REDS_INFO;
}

ErtsPortOpResult
erts_port_info(Process* c_p,
	       Port *prt,
	       Eterm item,
	       Eterm *retvalp)
{
    ErtsProc2PortSigData *sigdp;
    ErtsTryImmDrvCallResult try_call_res;
    ErtsTryImmDrvCallState try_call_state
	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
	    c_p,
	    prt,
	    ERTS_PORT_SFLGS_INVALID_LOOKUP,
	    0,
	    0,
	    am_info);

    try_call_res = try_imm_drv_call(&try_call_state);
    switch (try_call_res) {
    case ERTS_TRY_IMM_DRV_CALL_OK: {
	Eterm *hp, *hp_start;
	ErlHeapFragment *bp;
	Uint hsz = 0;
	Eterm value = make_port_info_term(&hp_start, &hp, &hsz, &bp, prt, item);
	finalize_imm_drv_call(&try_call_state);
	if (is_non_value(value))
	    return ERTS_PORT_OP_BADARG;
	else if (is_immed(value))
	    *retvalp = value;
	else {
	    Uint used_h_size = hp - hp_start;
	    hp = HAlloc(c_p, used_h_size);
	    *retvalp = copy_struct(value, used_h_size, &hp, &MSO(c_p));
	    free_message_buffer(bp);
	}
	BUMP_REDS(c_p, ERTS_PORT_REDS_INFO);
	return ERTS_PORT_OP_DONE;
    }
    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
	return ERTS_PORT_OP_DROPPED;
    case ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS:
    case ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK:
	/* Schedule call instead... */
	break;
    }

    sigdp = erts_port_task_alloc_p2p_sig_data();
    sigdp->flags = ERTS_P2P_SIG_TYPE_INFO;
    sigdp->u.info.item = item;

    return erts_schedule_proc2port_signal(c_p,
					  prt,
					  c_p->common.id,
					  retvalp,
					  sigdp,
					  0,
					  NULL,
					  port_sig_info);
}

typedef struct {
    Uint sched_id;
    Eterm pid;
    Uint32 refn[ERTS_REF_NUMBERS];
    erts_atomic32_t refc;
} ErtsIOBytesReq;

static void
reply_io_bytes(void *vreq)
{
    ErtsIOBytesReq *req = (ErtsIOBytesReq *) vreq;
    Process *rp;

    rp = erts_proc_lookup(req->pid);
    if (rp) {
	ErlOffHeap *ohp;
	ErtsMessage *mp;
	ErtsProcLocks rp_locks;
	Eterm ref, msg, ein, eout, *hp;
	Uint64 in, out;
	Uint hsz;
	ErtsSchedulerData *esdp = erts_get_scheduler_data();
	Uint sched_id = esdp->no;
	in = esdp->io.in;
	out = esdp->io.out;
	if (req->sched_id != sched_id)
	    rp_locks = 0;
	else {
	    in += (Uint64) erts_atomic64_read_nob(&bytes_in);
	    out += (Uint64) erts_atomic64_read_nob(&bytes_out);
	    rp_locks = ERTS_PROC_LOCK_MAIN;
	}

	hsz = 5 /* 4-tuple */ + ERTS_REF_THING_SIZE;

	erts_bld_uint64(NULL, &hsz, in);
	erts_bld_uint64(NULL, &hsz, out);

	mp = erts_alloc_message_heap(rp, &rp_locks, hsz, &hp, &ohp);

	ref = make_internal_ref(hp);
	write_ref_thing(hp, req->refn[0], req->refn[1], req->refn[2]);
	hp += ERTS_REF_THING_SIZE;

	ein = erts_bld_uint64(&hp, NULL, in);
	eout = erts_bld_uint64(&hp, NULL, out);

	msg = TUPLE4(hp, ref, make_small(sched_id), ein, eout);

	erts_queue_message(rp, rp_locks, mp, msg, am_system);

	if (req->sched_id == sched_id)
	    rp_locks &= ~ERTS_PROC_LOCK_MAIN;
	if (rp_locks)
	    erts_proc_unlock(rp, rp_locks);
    }

    if (erts_atomic32_dec_read_nob(&req->refc) == 0)
	erts_free(ERTS_ALC_T_IOB_REQ, req);
}

Eterm
erts_request_io_bytes(Process *c_p)
{
    Uint *hp;
    Eterm ref;
    Uint32 *refn;
    ErtsSchedulerData *esdp = erts_proc_sched_data(c_p);
    ErtsIOBytesReq *req = erts_alloc(ERTS_ALC_T_IOB_REQ,
				     sizeof(ErtsIOBytesReq));

    hp = HAlloc(c_p, ERTS_REF_THING_SIZE);
    ref = erts_sched_make_ref_in_buffer(esdp, hp);
    refn = internal_ref_numbers(ref);

    req->sched_id = esdp->no;
    req->pid = c_p->common.id;
    req->refn[0] = refn[0];
    req->refn[1] = refn[1];
    req->refn[2] = refn[2];
    erts_atomic32_init_nob(&req->refc,
			       (erts_aint32_t) erts_no_schedulers);

    if (erts_no_schedulers > 1)
	erts_schedule_multi_misc_aux_work(1,
                                          1,
					  erts_no_schedulers,
					  reply_io_bytes,
					  (void *) req);

    reply_io_bytes((void *) req);

    return ref;
}


typedef struct {
    fmtfn_t to;
    void *arg;
} prt_one_lnk_data;

static int prt_one_monitor(ErtsMonitor *mon, void *vprtd, Sint reds)
{
    ErtsMonitorData *mdp = erts_monitor_to_data(mon);
    prt_one_lnk_data *prtd = (prt_one_lnk_data *) vprtd;
    if (mon->type == ERTS_MON_TYPE_RESOURCE && erts_monitor_is_target(mon))
        erts_print(prtd->to, prtd->arg, "(%p,%T)", mon->other.ptr, mdp->ref);
    else
        erts_print(prtd->to, prtd->arg, "(%T,%T)", mon->other.item, mdp->ref);
    return 1;
}

static int prt_one_lnk(ErtsLink *lnk, void *vprtd, Sint reds)
{
    prt_one_lnk_data *prtd = (prt_one_lnk_data *) vprtd;
    erts_print(prtd->to, prtd->arg, "%T", lnk->other.item);
    return 1;
}

static void dump_port_state(fmtfn_t to, void *arg, erts_aint32_t state)
{
    erts_aint32_t rest;
    int unknown = 0;
    char delim = ' ';

    erts_print(to, arg, "State:");

    rest = state;
    while (rest) {
        erts_aint32_t chk = (rest ^ (rest-1)) & rest;  /* lowest set bit */
        char* s;

        rest &= ~chk;
        switch (chk) {
        case ERTS_PORT_SFLG_CONNECTED:          s = "CONNECTED"; break;
        case ERTS_PORT_SFLG_EXITING:            s = "EXITING"; break;
        case ERTS_PORT_SFLG_DISTRIBUTION:       s = "DISTR"; break;
        case ERTS_PORT_SFLG_BINARY_IO:          s = "BINARY_IO"; break;
        case ERTS_PORT_SFLG_SOFT_EOF:           s = "SOFT_EOF"; break;
        case ERTS_PORT_SFLG_CLOSING:            s = "CLOSING"; break;
        case ERTS_PORT_SFLG_SEND_CLOSED:        s = "SEND_CLOSED"; break;
        case ERTS_PORT_SFLG_LINEBUF_IO:         s = "LINEBUF_IO"; break;
        case ERTS_PORT_SFLG_FREE:               s = "FREE"; break;
        case ERTS_PORT_SFLG_INITIALIZING:       s = "INITIALIZING"; break;
        case ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK: s = "PORT_LOCK"; break;
        case ERTS_PORT_SFLG_INVALID:            s = "INVALID"; break;
        case ERTS_PORT_SFLG_HALT:               s = "HALT"; break;
#ifdef DEBUG
        case ERTS_PORT_SFLG_PORT_DEBUG:         s = "DEBUG"; break;
#endif
        default:
            unknown = 1;
            continue;
        }
        erts_print(to, arg, "%c%s", delim, s);
        delim = '|';
    }
    if (unknown || !state)
        erts_print(to, arg, "%c0x%x\n", delim, state);
    else
        erts_print(to, arg, "\n");
}

static void dump_port_task_flags(fmtfn_t to, void *arg, Port* p)
{
    erts_aint32_t flags = erts_atomic32_read_nob(&p->sched.flags);
    erts_aint32_t unknown = 0;
    char delim = ' ';

    if (!flags)
	return;

    erts_print(to, arg, "Task Flags:");

    while (flags) {
        erts_aint32_t chk = (flags ^ (flags-1)) & flags;  /* lowest set bit */
        char* s;

        flags &= ~chk;
        switch (chk) {
	case ERTS_PTS_FLG_IN_RUNQ:               s = "IN_RUNQ"; break;
	case ERTS_PTS_FLG_EXEC:                  s = "EXEC"; break;
	case ERTS_PTS_FLG_HAVE_TASKS:            s = "HAVE_TASKS"; break;
	case ERTS_PTS_FLG_EXIT:                  s = "EXIT"; break;
	case ERTS_PTS_FLG_BUSY_PORT:             s = "BUSY_PORT"; break;
	case ERTS_PTS_FLG_BUSY_PORT_Q:           s = "BUSY_Q"; break;
	case ERTS_PTS_FLG_CHK_UNSET_BUSY_PORT_Q: s = "CHK_UNSET_BUSY_Q"; break;
	case ERTS_PTS_FLG_HAVE_BUSY_TASKS:       s = "BUSY_TASKS"; break;
	case ERTS_PTS_FLG_HAVE_NS_TASKS:         s = "NS_TASKS"; break;
	case ERTS_PTS_FLG_PARALLELISM:           s = "PARALLELISM"; break;
	case ERTS_PTS_FLG_FORCE_SCHED:           s = "FORCE_SCHED"; break;
	case ERTS_PTS_FLG_EXITING:               s = "EXITING"; break;
	case ERTS_PTS_FLG_EXEC_IMM:              s = "EXEC_IMM"; break;
        default:
            unknown |= chk;
            continue;
        }
        erts_print(to, arg, "%c%s", delim, s);
        delim = '|';
    }
    if (unknown)
        erts_print(to, arg, "%cUNKNOWN(0x%x)\n", delim, unknown);
    else
        erts_print(to, arg, "\n");
}

void
print_port_info(Port *p, fmtfn_t to, void *arg)
{
    erts_aint32_t state = erts_atomic32_read_nob(&p->state);

    if (state & ERTS_PORT_SFLGS_DEAD)
	return;

    erts_print(to, arg, "=port:%T\n", p->common.id);
    dump_port_state(to, arg, state);
    dump_port_task_flags(to, arg, p);
    erts_print(to, arg, "Slot: %d\n", internal_port_index(p->common.id));
    if (state & ERTS_PORT_SFLG_CONNECTED) {
	erts_print(to, arg, "Connected: %T", ERTS_PORT_GET_CONNECTED(p));
	erts_print(to, arg, "\n");
    }

    if (ERTS_P_LINKS(p)) {
	prt_one_lnk_data prtd;
	prtd.to = to;
	prtd.arg = arg;
	erts_print(to, arg, "Links: ");
	erts_link_tree_foreach(ERTS_P_LINKS(p), prt_one_lnk, (void *) &prtd);
	erts_print(to, arg, "\n");
    }
    if (ERTS_P_MONITORS(p) || ERTS_P_LT_MONITORS(p)) {
	prt_one_lnk_data prtd;
	prtd.to = to;
	prtd.arg = arg;
	erts_print(to, arg, "Monitors: ");
	erts_monitor_tree_foreach(ERTS_P_MONITORS(p), prt_one_monitor,
                                  (void *) &prtd);
	erts_monitor_list_foreach(ERTS_P_LT_MONITORS(p), prt_one_monitor,
                                  (void *) &prtd);
	erts_print(to, arg, "\n");
    }
    if (p->suspended) {
	erts_print(to, arg, "Suspended: ");
	erts_proclist_dump(to, arg, p->suspended);
    }

    if (p->common.u.alive.reg != NULL)
	erts_print(to, arg, "Registered as: %T\n", p->common.u.alive.reg->name);

    if (p->drv_ptr == &fd_driver) {
	erts_print(to, arg, "Port is UNIX fd not opened by emulator: %s\n", p->name);
    } else if (p->drv_ptr == &vanilla_driver) {
	erts_print(to, arg, "Port is a file: %s\n",p->name);
    } else if (p->drv_ptr == &spawn_driver) {
	erts_print(to, arg, "Port controls external process: %s\n",p->name);
#ifndef __WIN32__
    } else if (p->drv_ptr == &forker_driver) {
	erts_print(to, arg, "Port controls forker process: %s\n",p->name);
#endif
    } else {
	erts_print(to, arg, "Port controls linked-in driver: %s\n",p->name);
    }
    erts_print(to, arg, "Input: %beu\n", p->bytes_in);
    erts_print(to, arg, "Output: %beu\n", p->bytes_out);
    erts_print(to, arg, "Queue: %beu\n", erts_ioq_size(&p->ioq));
    {
        Eterm port_data = erts_port_data_read(p);
        if (port_data != am_undefined)
            erts_print(to, arg, "Port Data: %T\n", port_data);
    }
}

void
set_busy_port(ErlDrvPort dprt, int on)
{
    Port *prt;
    erts_aint32_t flags;

#ifdef USE_VM_PROBES
    DTRACE_CHARBUF(port_str, 16);
#endif

    ERTS_CHK_NO_PROC_LOCKS;

    prt = erts_drvport2port(dprt);
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return;

    if (on) {
	flags = erts_atomic32_read_bor_acqb(&prt->sched.flags,
						ERTS_PTS_FLG_BUSY_PORT);
	if (flags & ERTS_PTS_FLG_BUSY_PORT)
	    return; /* Already busy */

	if (flags & ERTS_PTS_FLG_HAVE_NS_TASKS)
	    erts_port_task_abort_nosuspend_tasks(prt);

#ifdef USE_VM_PROBES
        if (DTRACE_ENABLED(port_busy)) {
            erts_snprintf(port_str, sizeof(DTRACE_CHARBUF_NAME(port_str)),
                          "%T", prt->common.id);
            DTRACE1(port_busy, port_str);
        }
#endif
    } else {
	flags = erts_atomic32_read_band_acqb(&prt->sched.flags,
						 ~ERTS_PTS_FLG_BUSY_PORT);
	if (!(flags & ERTS_PTS_FLG_BUSY_PORT))
	    return; /* Already non-busy */

#ifdef USE_VM_PROBES
        if (DTRACE_ENABLED(port_not_busy)) {
            erts_snprintf(port_str, sizeof(DTRACE_CHARBUF_NAME(port_str)),
                          "%T", prt->common.id);
            DTRACE1(port_not_busy, port_str);
        }
#endif
	if (erts_prtsd_get(prt, ERTS_PRTSD_DIST_ENTRY) != NULL) {
	    /*
	     * Processes suspended on distribution ports are
	     * normally queued on the dist entry.
	     */
	    erts_dist_port_not_busy(prt);
	}

	if (!(flags & ERTS_PTS_FLG_BUSY_PORT_Q))
	    erts_port_resume_procs(prt);
    }
}

void
erts_port_resume_procs(Port *prt)
{
    /*
     * Resume, in a round-robin fashion, all processes waiting on the port.
     * 
     * This version submitted by Tony Rogvall. The earlier version used
     * to resume the processes in order, which caused starvation of all but
     * the first process.
     */
    ErtsProcList *plp;

    erts_port_task_sched_lock(&prt->sched);
    plp = prt->suspended;
    prt->suspended = NULL;
    erts_port_task_sched_unlock(&prt->sched);

    if (erts_proclist_fetch(&plp, NULL)) {

#ifdef USE_VM_PROBES
	/*
	 * Hrm, for blocked dist ports, plp always seems to be NULL.
	 * That's not so fun.
	 * Well, another way to get the same info is using a D
	 * script to correlate an earlier process-port_blocked+pid
	 * event with a later process-scheduled event.  That's
	 * subject to the multi-CPU races with how events are
	 * handled, but hey, that way works most of the time.
	 */
	if (DTRACE_ENABLED(process_port_unblocked)) {
	    DTRACE_CHARBUF(port_str, 16);
	    DTRACE_CHARBUF(pid_str, 16);
	    ErtsProcList* plp2 = plp;

	    erts_snprintf(port_str, sizeof(DTRACE_CHARBUF_NAME(port_str)), "%T", prt->common.id);
	    while (plp2 != NULL) {
		erts_snprintf(pid_str, sizeof(DTRACE_CHARBUF_NAME(pid_str)), "%T", plp2->u.pid);
		DTRACE2(process_port_unblocked, pid_str, port_str);
	    }
	}
#endif

	/* First proc should be resumed last */
	if (plp->next) {
	    plp->next->prev = NULL;
	    erts_resume_processes(plp->next);
	    plp->next = NULL;
	}
	erts_resume_processes(plp);
    }
}

void set_port_control_flags(ErlDrvPort port_num, int flags)
{
    Port *prt = erts_drvport2port(port_num);
    if (prt != ERTS_INVALID_ERL_DRV_PORT)
	prt->control_flags = flags;
}

int get_port_flags(ErlDrvPort ix)
{
    int flags;
    Port *prt;
    erts_aint32_t state;

    prt = erts_drvport2port_state(ix, &state);
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return 0;

    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));

    flags = 0;
    if (state & ERTS_PORT_SFLG_BINARY_IO)
	flags |= PORT_FLAG_BINARY;
    if (state & ERTS_PORT_SFLG_LINEBUF_IO)
	flags |= PORT_FLAG_LINE;

    return flags;
}

void erts_raw_port_command(Port* p, byte* buf, Uint len)
{
    ERTS_MSACC_PUSH_STATE_M();

    ERTS_CHK_NO_PROC_LOCKS;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(p));

    if (len > (Uint) INT_MAX)
	erts_exit(ERTS_ABORT_EXIT,
		 "Absurdly large data buffer (%beu bytes) passed to"
		 "output callback of %s driver.\n",
		 len,
		 p->drv_ptr->name ? p->drv_ptr->name : "unknown");

    p->caller = NIL;
#ifdef USE_VM_PROBES
    if (DTRACE_ENABLED(driver_output)) {
        DTRACE_CHARBUF(port_str, DTRACE_TERM_BUF_SIZE);

        dtrace_port_str(p, port_str);
        DTRACE4(driver_output, "-raw-", port_str, p->name, len);
    }
#endif
    ERTS_MSACC_SET_STATE_CACHED_M(ERTS_MSACC_STATE_PORT);
    (*p->drv_ptr->output)((ErlDrvData)p->drv_data, (char*) buf, (int) len);
    ERTS_MSACC_POP_STATE_M();
}

int async_ready(Port *p, void* data)
{
    int need_free = 1;

    ERTS_CHK_NO_PROC_LOCKS;

    if (p) {
	ERTS_LC_ASSERT(erts_lc_is_port_locked(p));
	if (p->drv_ptr->ready_async != NULL) {
	    ERTS_MSACC_PUSH_AND_SET_STATE_M(ERTS_MSACC_STATE_PORT);
#ifdef USE_VM_PROBES
            if (DTRACE_ENABLED(driver_ready_async)) {
                DTRACE_FORMAT_COMMON_PID_AND_PORT(ERTS_PORT_GET_CONNECTED(p), p)
                DTRACE3(driver_ready_async, process_str, port_str, p->name);
            }
#endif
#ifdef USE_LTTNG_VM_TRACEPOINTS 
            if (LTTNG_ENABLED(driver_ready_async)) {
                lttng_decl_portbuf(port_str);
                lttng_decl_procbuf(proc_str);
                lttng_pid_to_str(ERTS_PORT_GET_CONNECTED(p), proc_str);
                lttng_port_to_str(p, port_str);
                LTTNG3(driver_ready_async, proc_str, port_str, p->name);
            }
#endif
	    (*p->drv_ptr->ready_async)((ErlDrvData)p->drv_data, data);
	    need_free = 0;
	    ERTS_MSACC_POP_STATE_M();

	}
	erts_port_driver_callback_epilogue(p, NULL);
    }
    return need_free;
}

static void
report_missing_drv_callback(Port *p, char *drv_type, char *callback)
{
    ErtsPortNames *pnp = erts_get_port_names(p->common.id,
					     ERTS_Port2ErlDrvPort(p));
    char *unknown = "<unknown>";
    char *drv_name = pnp->driver_name ? pnp->driver_name : unknown;
    char *prt_name = pnp->name ? pnp->name : unknown;
    erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();    
    erts_dsprintf(dsbufp, "%T: %s driver '%s' ", p->common.id, drv_type, drv_name);
    if (sys_strcmp(drv_name, prt_name) != 0)
	erts_dsprintf(dsbufp, "(%s) ", prt_name);
    erts_dsprintf(dsbufp, "does not implement the %s callback!\n", callback);
    erts_free_port_names(pnp);
    erts_send_error_to_logger_nogl(dsbufp);
}

void
erts_stale_drv_select(Eterm port,
		      ErlDrvPort drv_port,
		      ErlDrvEvent hndl,
		      int mode,
		      int deselect)
{
    char *type;
    ErtsPortNames *pnp;
    erts_dsprintf_buf_t *dsbufp;

    if (drv_port == ERTS_INVALID_ERL_DRV_PORT) {
	Port *prt = erts_port_lookup_raw(port);
	if (prt)
	    drv_port = ERTS_Port2ErlDrvPort(prt);
	else
	    drv_port = ERTS_INVALID_ERL_DRV_PORT;
    }

    pnp = erts_get_port_names(port, drv_port);

    switch (mode) {
    case ERL_DRV_READ | ERL_DRV_WRITE:
	type = "Input/Output";
    case ERL_DRV_WRITE:
	type = "Output";
    case ERL_DRV_READ:
	type = "Input";
    default:
        type = "";
    }
    if (deselect) {
        driver_select(drv_port, hndl,
                      mode | ERL_DRV_USE_NO_CALLBACK,
                      0);
    }

    dsbufp = erts_create_logger_dsbuf();
    erts_dsprintf(dsbufp,
		  "%T: %s: %s driver gone away without deselecting!\n",
		  port,
		  pnp->name ? pnp->name : "<unknown>",
		  type);
    erts_free_port_names(pnp);
    erts_send_error_to_logger_nogl(dsbufp);
}

ErtsPortNames *
erts_get_port_names(Eterm id, ErlDrvPort drv_port)
{
    Port *prt;
    ErtsPortNames *pnp;
    ASSERT(is_nil(id) || is_internal_port(id));

    prt = ERTS_ErlDrvPort2Port(drv_port);
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	prt = erts_port_lookup_raw(id);

    if (!prt) {
	pnp = erts_alloc(ERTS_ALC_T_PORT_NAMES, sizeof(ErtsPortNames));
	pnp->name = NULL;
	pnp->driver_name = NULL;
    }
    else {
	int len;
        int nlen;
        char *driver_name;

        len = nlen = prt->name ? sys_strlen(prt->name) + 1 : 0;
        driver_name = (prt->drv_ptr ? prt->drv_ptr->name : NULL);
        len += driver_name ? sys_strlen(driver_name) + 1 : 0;

        pnp = erts_alloc(ERTS_ALC_T_PORT_NAMES,
                         sizeof(ErtsPortNames) + len);

        if (!prt->name)
            pnp->name = NULL;
        else {
            pnp->name = ((char *) pnp) + sizeof(ErtsPortNames);
            sys_strcpy(pnp->name, prt->name);
        }
        if (!driver_name)
            pnp->driver_name = NULL;
        else {
            pnp->driver_name = (((char *) pnp)
                                + sizeof(ErtsPortNames)
                                + nlen);
            sys_strcpy(pnp->driver_name, driver_name);
        }
    }
    return pnp;
}

void
erts_free_port_names(ErtsPortNames *pnp)
{
    erts_free(ERTS_ALC_T_PORT_NAMES, pnp);
}

ErlDrvTermData driver_mk_term_nil(void)
{
    return driver_term_nil;
}

void driver_report_exit(ErlDrvPort ix, int status)
{
   Eterm* hp;
   ErlOffHeap *ohp;
   Eterm tuple;
   Process *rp;
   Eterm pid;
   ErtsMessage *mp;
   ErtsProcLocks rp_locks = 0;
   int scheduler = erts_get_scheduler_id() != 0;
   Port* prt = erts_drvport2port(ix);
   int trace_send = IS_TRACED_FL(prt, F_TRACE_SEND);

   if (prt == ERTS_INVALID_ERL_DRV_PORT)
       return;

   ERTS_CHK_NO_PROC_LOCKS;
   ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));

   pid = ERTS_PORT_GET_CONNECTED(prt);
   ASSERT(is_internal_pid(pid));

   rp = (scheduler
	 ? erts_proc_lookup(pid)
	 : erts_pid2proc_opt(NULL, 0, pid, 0, ERTS_P2P_FLG_INC_REFC));
   if (!rp)
       return;

   mp = erts_alloc_message_heap(trace_send ? NULL : rp, &rp_locks, 3+3, &hp, &ohp);

   tuple = TUPLE2(hp, am_exit_status, make_small(status));
   hp += 3;
   tuple = TUPLE2(hp, prt->common.id, tuple);

    if (IS_TRACED_FL(prt, F_TRACE_SEND))
        trace_port_send(prt, pid, tuple, 1);

   erts_queue_message(rp, rp_locks, mp, tuple, prt->common.id);

   erts_proc_unlock(rp, rp_locks);
   if (!scheduler)
       erts_proc_dec_refc(rp);
}

#define ERTS_B2T_STATES_DEF_STATES_SZ 5
#define ERTS_B2T_STATES_DEF_STATES_INC 100

struct b2t_states__ {
    int len;
    int ix;
    int used;
    ErtsBinary2TermState *state;
    ErtsBinary2TermState def_states[ERTS_B2T_STATES_DEF_STATES_SZ];
#ifdef DEBUG
    byte **org_ext;
    byte *def_org_ext[ERTS_B2T_STATES_DEF_STATES_SZ];
#endif
};

static ERTS_INLINE void
init_b2t_states(struct b2t_states__ *b2tsp)
{
    b2tsp->len = ERTS_B2T_STATES_DEF_STATES_SZ;
    b2tsp->ix = 0;
    b2tsp->used = 0;
    b2tsp->state = &b2tsp->def_states[0];
#ifdef DEBUG
    b2tsp->org_ext = &b2tsp->def_org_ext[0];
#endif
}

static ERTS_INLINE void
grow_b2t_states(struct b2t_states__ *b2tsp)
{
    if (b2tsp->state != &b2tsp->def_states[0]) {
	b2tsp->len += ERTS_B2T_STATES_DEF_STATES_INC;
	b2tsp->state = erts_realloc(ERTS_ALC_T_TMP,
				    b2tsp->state,
				    sizeof(ErtsBinary2TermState)*b2tsp->len);
#ifdef DEBUG
	b2tsp->org_ext = erts_realloc(ERTS_ALC_T_TMP,
				      b2tsp->org_ext,
				      sizeof(char *)*b2tsp->len);
#endif
    }
    else {
	ErtsBinary2TermState *new_states;
	new_states = erts_alloc(ERTS_ALC_T_TMP,
				(sizeof(ErtsBinary2TermState)
				 *ERTS_B2T_STATES_DEF_STATES_INC));
	sys_memcpy((void *) new_states,
		   (void *) b2tsp->state,
		   sizeof(ErtsBinary2TermState)*ERTS_B2T_STATES_DEF_STATES_SZ);
	b2tsp->state = new_states;
	b2tsp->len = ERTS_B2T_STATES_DEF_STATES_INC;
#ifdef DEBUG
	{
	    byte **new_org_ext = erts_alloc(ERTS_ALC_T_TMP,
					    (sizeof(char *)
					     *ERTS_B2T_STATES_DEF_STATES_INC));
	    sys_memcpy((void *) new_org_ext,
		       (void *) b2tsp->org_ext,
		       sizeof(char *)*ERTS_B2T_STATES_DEF_STATES_SZ);
	    b2tsp->org_ext = new_org_ext;
	}
#endif
    }
}

static ERTS_INLINE void
cleanup_b2t_states(struct b2t_states__ *b2tsp)
{
    if (b2tsp->state != &b2tsp->def_states[0]) {
	erts_free(ERTS_ALC_T_TMP, b2tsp->state);
#ifdef DEBUG
	erts_free(ERTS_ALC_T_TMP, b2tsp->org_ext);
#endif
    }
}


/*
 * Generate an Erlang term from data in an array (representing a simple stack
 * machine to build terms).
 * Returns:
 * 	-1 on error in input data
 *       0 if the message was not delivered (bad to pid or closed port)
 *       1 if the message was delivered successfully
 */

static int
driver_deliver_term(Port *prt, Eterm to, ErlDrvTermData* data, int len)
{
#define HEAP_EXTRA 200
#define ERTS_DDT_FAIL do { res = -1; goto done; } while (0)
    Uint need = 0;
    int depth = 0;
    int res = 0;
    ErlDrvTermData* ptr;
    ErlDrvTermData* ptr_end;
    DECLARE_ESTACK(stack); 
    Eterm mess;
    Process* rp = NULL;
    ErtsHeapFactory factory;
    ErtsProcLocks rp_locks = 0;
    struct b2t_states__ b2t;
    int scheduler;
    ErtsSchedulerData *esdp = erts_get_scheduler_data();

    ERTS_UNDEF(mess,NIL);
    ERTS_UNDEF(scheduler,1);

    factory.mode = FACTORY_CLOSED;
    init_b2t_states(&b2t);

    /*
     * We used to check port and process here. In the SMP enabled emulator,
     * however, we don't want to that until we have verified the term.
     */

    /*
     * Check ErlDrvTermData for consistency and calculate needed heap size
     * and stack depth.
     */
    ptr = data;
    ptr_end = ptr + len;

    while (ptr < ptr_end) {
	ErlDrvTermData tag = *ptr++;

#define ERTS_DDT_CHK_ENOUGH_ARGS(NEED) \
	if (ptr+((NEED)-1) >= ptr_end) ERTS_DDT_FAIL;

	switch(tag) {
	case ERL_DRV_NIL: /* no arguments */
	    depth++;
	    break;
	case ERL_DRV_ATOM: /* atom argument */
	    ERTS_DDT_CHK_ENOUGH_ARGS(1);
	    if (is_not_atom(ptr[0])) ERTS_DDT_FAIL;
	    ptr++;
	    depth++;
	    break;
	case ERL_DRV_INT:  /* signed int argument */
	    ERTS_DDT_CHK_ENOUGH_ARGS(1);
	    /* check for bignum */
	    if (!IS_SSMALL((Sint)ptr[0]))
		need += BIG_UINT_HEAP_SIZE;  /* use small_to_big */
	    ptr++;
	    depth++;
	    break;
	case ERL_DRV_UINT:  /* unsigned int argument */
	    ERTS_DDT_CHK_ENOUGH_ARGS(1);
	    /* check for bignum */
	    if (!IS_USMALL(0, (Uint)ptr[0]))
		need += BIG_UINT_HEAP_SIZE;  /* use small_to_big */
	    ptr++;
	    depth++;
	    break;
	case ERL_DRV_INT64:  /* pointer to signed 64-bit int argument  */
	    ERTS_DDT_CHK_ENOUGH_ARGS(1);
	    erts_bld_sint64(NULL, &need, *((Sint64 *) ptr[0]));
	    ptr++;
	    depth++;
	    break;
	case ERL_DRV_UINT64:  /* pointer to unsigned 64-bit int argument */
	    ERTS_DDT_CHK_ENOUGH_ARGS(1);
	    erts_bld_uint64(NULL, &need, *((Uint64 *) ptr[0]));
	    ptr++;
	    depth++;
	    break;
	case ERL_DRV_PORT:  /* port argument */
	    ERTS_DDT_CHK_ENOUGH_ARGS(1);
	    if (is_not_internal_port(ptr[0])) ERTS_DDT_FAIL;
	    ptr++;
	    depth++;
	    break;
	case ERL_DRV_BINARY: { /* ErlDrvBinary*, size, offs */
	    ErlDrvBinary* b;
	    Uint size;
	    Uint offset;
	    ERTS_DDT_CHK_ENOUGH_ARGS(3);
	    b = (ErlDrvBinary*) ptr[0];
	    size = ptr[1];
	    offset = ptr[2];
	    if (!b || size + offset > b->orig_size)
		ERTS_DDT_FAIL; /* No binary or outside the binary */
	    need += (size <= ERL_ONHEAP_BIN_LIMIT
			 ? heap_bin_size(size)
			 : PROC_BIN_SIZE);
	    ptr += 3;
	    depth++;
	    break;
	}
	case ERL_DRV_BUF2BINARY: { /* char*, size */
	    byte *bufp;
	    Uint size;
	    ERTS_DDT_CHK_ENOUGH_ARGS(2);
	    bufp = (byte *) ptr[0];
	    size = (Uint) ptr[1];
	    if (!bufp && size > 0) ERTS_DDT_FAIL; 
	    need += (size <= ERL_ONHEAP_BIN_LIMIT
		     ? heap_bin_size(size)
		     : PROC_BIN_SIZE);
	    ptr += 2;
	    depth++;
	    break;
	}
	case ERL_DRV_STRING: /* char*, length */
	    ERTS_DDT_CHK_ENOUGH_ARGS(2);
	    if ((char *) ptr[0] == NULL || (int) ptr[1] < 0) ERTS_DDT_FAIL;
	    need += ptr[1] * 2;
	    ptr += 2;
	    depth++;
	    break;
	case ERL_DRV_STRING_CONS: /* char*, length */
	    ERTS_DDT_CHK_ENOUGH_ARGS(2);
	    if ((char *) ptr[0] == NULL || (int) ptr[1] < 0) ERTS_DDT_FAIL;
	    need += ptr[1] * 2;
	    if (depth < 1) ERTS_DDT_FAIL;
	    ptr += 2;
	    break;
	case ERL_DRV_LIST: /* int */
	    ERTS_DDT_CHK_ENOUGH_ARGS(1);
	    if ((int) ptr[0] <= 0) ERTS_DDT_FAIL;
	    need += (ptr[0]-1)*2;  /* list cells */
	    depth -= ptr[0];
	    if (depth < 0) ERTS_DDT_FAIL;
	    ptr++;
	    depth++;
	    break;
	case ERL_DRV_TUPLE: { /* int */
	    ERTS_DDT_CHK_ENOUGH_ARGS(1);
	    if ((int) ptr[0] < 0) ERTS_DDT_FAIL;
	    need += ptr[0]+1;   /* vector positions + arityval */
	    depth -= ptr[0];
	    if (depth < 0) ERTS_DDT_FAIL;
	    ptr++;
	    depth++;
	    break;
	}
	case ERL_DRV_PID: /* pid argument */
	    ERTS_DDT_CHK_ENOUGH_ARGS(1);
	    if (is_not_internal_pid(ptr[0])) ERTS_DDT_FAIL;
	    ptr++;
	    depth++;
	    break;
	case ERL_DRV_FLOAT: /* double * */
	    ERTS_DDT_CHK_ENOUGH_ARGS(1);
	    need += FLOAT_SIZE_OBJECT;
	    ptr++;
	    depth++;
	    break;
	case ERL_DRV_EXT2TERM: { /* char *ext, int size */
	    byte* ext;
	    Sint size;
	    Sint hsz;

	    ERTS_DDT_CHK_ENOUGH_ARGS(2);
	    ext = (byte *) ptr[0];
	    size = (Sint) ptr[1];
	    if (!ext || size <= 0)
		ERTS_DDT_FAIL;
	    if (b2t.len <= b2t.ix)
		grow_b2t_states(&b2t);
#ifdef DEBUG
	    b2t.org_ext[b2t.ix] = ext;
#endif
	    hsz = erts_binary2term_prepare(&b2t.state[b2t.ix], ext, size);
	    if (hsz < 0)
		ERTS_DDT_FAIL; /* Invalid data */
	    b2t.state[b2t.ix++].heap_size = hsz;
	    need += hsz;
	    ptr += 2;
	    depth++;
	    break;
	}
	case ERL_DRV_MAP: { /* int */
	    ERTS_DDT_CHK_ENOUGH_ARGS(1);
	    if ((int) ptr[0] < 0) ERTS_DDT_FAIL;
            if (ptr[0] > MAP_SMALL_MAP_LIMIT) {
                need += HASHMAP_ESTIMATED_HEAP_SIZE(ptr[0]);
            } else {
                need += MAP_HEADER_FLATMAP_SZ + 1 + 2*ptr[0];
            }
	    depth -= 2*ptr[0];
	    if (depth < 0) ERTS_DDT_FAIL;
	    ptr++;
	    depth++;
	    break;
	}

	default:
	    ERTS_DDT_FAIL;
	}
#undef ERTS_DDT_CHK_ENOUGH_ARGS
    }

    if ((depth != 1) || (ptr != ptr_end))
	ERTS_DDT_FAIL;

    b2t.used = b2t.ix;
    b2t.ix = 0;

    /*
     * The term is OK. Go ahead and validate the process.
     */

    /*
     * Increase refc on proc if done from a non-scheduler thread.
     */
    scheduler = erts_get_scheduler_id() != 0;
    rp = (scheduler
	  ? erts_proc_lookup(to)
	  : erts_pid2proc_opt(NULL, 0, to, 0, ERTS_P2P_FLG_INC_REFC));
    if (!rp) {
        if (!prt || !IS_TRACED_FL(prt, F_TRACE_SEND))
            goto done;
        if (!erts_is_tracer_proc_enabled_send(NULL, 0, &prt->common))
            goto done;

	res = -2;

        /* We allocate a temporary heap to be used to create
           the message that may be sent using tracing */
        erts_factory_tmp_init(&factory, erts_alloc(ERTS_ALC_T_DRIVER, need*sizeof(Eterm)),
                              need, ERTS_ALC_T_DRIVER);

    } else {
        /* We force the creation of a heap fragment (rp == NULL) when send
           tracing so that we don't have the main lock of the process while
           tracing */
        Process *trace_rp = prt && IS_TRACED_FL(prt, F_TRACE_SEND) ? NULL : rp;
        (void) erts_factory_message_create(&factory, trace_rp, &rp_locks, need);
        res = 1;
    }

    /*
     * Interpret the instructions and build the term.
     */
    ptr = data;
    while (ptr < ptr_end) {
	ErlDrvTermData tag = *ptr++;

	switch(tag) {
	case ERL_DRV_NIL: /* no arguments */
	    mess = NIL;
	    break;

	case ERL_DRV_ATOM: /* atom argument */
	    mess = ptr[0];
	    ptr++;
	    break;

	case ERL_DRV_INT:  /* signed int argument */
	    erts_reserve_heap(&factory, BIG_UINT_HEAP_SIZE);
	    if (IS_SSMALL((Sint)ptr[0]))
		mess = make_small((Sint)ptr[0]);
	    else {
		mess = small_to_big((Sint)ptr[0], factory.hp);
		factory.hp += BIG_UINT_HEAP_SIZE;
	    }
	    ptr++;
	    break;

	case ERL_DRV_UINT:  /* unsigned int argument */
	    erts_reserve_heap(&factory, BIG_UINT_HEAP_SIZE);
	    if (IS_USMALL(0, (Uint)ptr[0]))
		mess = make_small((Uint)ptr[0]);
	    else {
		mess = uint_to_big((Uint)ptr[0], factory.hp);
		factory.hp += BIG_UINT_HEAP_SIZE;
	    }
	    ptr++;
	    break;

	case ERL_DRV_INT64: /* pointer to unsigned 64-bit int argument */
	    erts_reserve_heap(&factory, BIG_NEED_FOR_BITS(64));
	    mess = erts_bld_sint64(&factory.hp, NULL, *((Sint64 *) ptr[0]));
	    ptr++;
	    break;

	case ERL_DRV_UINT64: /* pointer to unsigned 64-bit int argument */
	    erts_reserve_heap(&factory, BIG_NEED_FOR_BITS(64));
	    mess = erts_bld_uint64(&factory.hp, NULL, *((Uint64 *) ptr[0]));
	    ptr++;
	    break;

	case ERL_DRV_PORT:  /* port argument */
	    mess = ptr[0];
	    ptr++;
	    break;

	case ERL_DRV_BINARY: { /* ErlDrvBinary*, size, offs */
	    ErlDrvBinary* b = (ErlDrvBinary*) ptr[0];
	    Uint size = ptr[1];
	    Uint offset = ptr[2];

	    if (esdp)
		esdp->io.in += (Uint64) size;
	    else
		erts_atomic64_add_nob(&bytes_in, (erts_aint64_t) size);

	    if (size <= ERL_ONHEAP_BIN_LIMIT) {
		ErlHeapBin* hbp = (ErlHeapBin *) erts_produce_heap(&factory,
								   heap_bin_size(size), HEAP_EXTRA);
		hbp->thing_word = header_heap_bin(size);
		hbp->size = size;
		if (size > 0) {
		    sys_memcpy((void *) hbp->data, (void *) (((byte*) b->orig_bytes) + offset), size);
		}
		mess = make_binary(hbp);
	    }
	    else {
		ProcBin* pb = (ProcBin *) erts_produce_heap(&factory,
							    PROC_BIN_SIZE, HEAP_EXTRA);
		driver_binary_inc_refc(b);  /* caller will free binary */
		pb->thing_word = HEADER_PROC_BIN;
		pb->size = size;
		pb->next = factory.off_heap->first;
		factory.off_heap->first = (struct erl_off_heap_header*)pb;
		pb->val = ErlDrvBinary2Binary(b);
		pb->bytes = ((byte*) b->orig_bytes) + offset;
		pb->flags = 0;
		mess =  make_binary(pb);
		OH_OVERHEAD(factory.off_heap, pb->size / sizeof(Eterm));
	    }
	    ptr += 3;
	    break;
	}

	case ERL_DRV_BUF2BINARY: { /* char*, size */
	    byte *bufp = (byte *) ptr[0];
	    Uint size = (Uint) ptr[1];

	    if (esdp)
		esdp->io.in += (Uint64) size;
	    else
		erts_atomic64_add_nob(&bytes_in, (erts_aint64_t) size);

	    if (size <= ERL_ONHEAP_BIN_LIMIT) {
		ErlHeapBin* hbp = (ErlHeapBin *) erts_produce_heap(&factory,
								   heap_bin_size(size),
								   HEAP_EXTRA);
		hbp->thing_word = header_heap_bin(size);
		hbp->size = size;
		if (size > 0) {
		    ASSERT(bufp);
		    sys_memcpy((void *) hbp->data, (void *) bufp, size);
		}
		mess = make_binary(hbp);
	    }
	    else {
		Eterm* hp;
		Binary* bp = erts_bin_nrml_alloc(size);
		ASSERT(bufp);
		sys_memcpy((void *) bp->orig_bytes, (void *) bufp, size);
                hp = erts_produce_heap(&factory, PROC_BIN_SIZE, HEAP_EXTRA);
                mess = erts_build_proc_bin(factory.off_heap, hp, bp);
	    }
	    ptr += 2;
	    break;
	}

	case ERL_DRV_STRING: /* char*, length */
	    if (esdp)
		esdp->io.in += (Uint64) ptr[1];
	    else
		erts_atomic64_add_nob(&bytes_in, (erts_aint64_t) ptr[1]);
	    erts_reserve_heap(&factory, 2*ptr[1]);
	    mess = buf_to_intlist(&factory.hp, (char*)ptr[0], ptr[1], NIL);
	    ptr += 2;
	    break;

	case ERL_DRV_STRING_CONS:  /* char*, length */
	    mess = ESTACK_POP(stack);
	    erts_reserve_heap(&factory, 2*ptr[1]);
	    mess = buf_to_intlist(&factory.hp, (char*)ptr[0], ptr[1], mess);
	    ptr += 2;
	    break;

	case ERL_DRV_LIST: { /* unsigned */
	    Uint i = (int) ptr[0]; /* i > 0 */

	    mess = ESTACK_POP(stack);
	    i--;
	    erts_reserve_heap(&factory, 2*i);
	    while(i > 0) {
		Eterm hd = ESTACK_POP(stack);

		mess = CONS(factory.hp, hd, mess);
		factory.hp += 2;
		i--;
	    }
	    ptr++;
	    break;
	}

	case ERL_DRV_TUPLE: { /* int */
	    int size = (int)ptr[0];
            if (size == 0) {
                mess = ERTS_GLOBAL_LIT_EMPTY_TUPLE;
                ptr++;
                break;
            } else {
                Eterm* tp = erts_produce_heap(&factory, size+1, HEAP_EXTRA);

                *tp = make_arityval(size);
                mess = make_tuple(tp);

                tp += size;   /* point at last element */

                while(size--) {
                    *tp-- = ESTACK_POP(stack);
                }
                ptr++;
                break;
            }
	}

	case ERL_DRV_PID: /* pid argument */
	    mess = ptr[0];
	    ptr++;
	    break;

	case ERL_DRV_FLOAT: { /* double * */
	    FloatDef f;
	    Eterm* fp = erts_produce_heap(&factory, FLOAT_SIZE_OBJECT, HEAP_EXTRA);

	    mess = make_float(fp);
	    f.fd = *((double *) ptr[0]);
            if (!erts_isfinite(f.fd))
                ERTS_DDT_FAIL;
	    PUT_DOUBLE(f, fp);
	    ptr++;
	    break;
	}

	case ERL_DRV_EXT2TERM: /* char *ext, int size */
	    ASSERT(b2t.org_ext[b2t.ix] == (byte *) ptr[0]);

	    erts_reserve_heap(&factory, b2t.state[b2t.ix].heap_size);
	    mess = erts_binary2term_create(&b2t.state[b2t.ix++], &factory);
	    if (mess == THE_NON_VALUE)
		ERTS_DDT_FAIL;
	    ptr += 2;
	    break;

	case ERL_DRV_MAP: { /* int */
	    int size = (int)ptr[0];
            if (size > MAP_SMALL_MAP_LIMIT) {
                int ix = 2*size;
                Eterm* leafs;

		erts_produce_heap(&factory, ix, HEAP_EXTRA);
		leafs = factory.hp;
                while(ix--) { *--leafs = ESTACK_POP(stack); }

                mess = erts_hashmap_from_array(&factory, leafs, size, 1);
                if (is_non_value(mess))
                    ERTS_DDT_FAIL;
            } else {
                Eterm* vp;
                flatmap_t *mp;
		Eterm* tp = erts_produce_heap(&factory,
					      2*size + (size==0 ? 0 : 1) + MAP_HEADER_FLATMAP_SZ,
					      HEAP_EXTRA);
                if (size != 0) {
                    *tp = make_arityval(size);
                }
                mp = (flatmap_t*) (tp + (size==0 ? 0 : 1) + size);
                mp->thing_word = MAP_HEADER_FLATMAP;
                mp->size = size;
                mp->keys = (size!= 0 ? make_tuple(tp) : ERTS_GLOBAL_LIT_EMPTY_TUPLE);
                mess = make_flatmap(mp);

                tp += size;    /* point at last key */
                vp = factory.hp - 1;   /* point at last value */

                while(size--) {
                    *vp-- = ESTACK_POP(stack);
                    *tp-- = ESTACK_POP(stack);
                }
                if (!erts_validate_and_sort_flatmap(mp))
                    ERTS_DDT_FAIL;
            }
            ptr++;
	    break;
	}

	}
	ESTACK_PUSH(stack, mess);
    }

 done:

    if (res > 0) {
	Eterm from = am_undefined;
	mess = ESTACK_POP(stack);  /* get resulting value */
	erts_factory_trim_and_close(&factory, &mess, 1);

	if (prt) {
	    if (IS_TRACED_FL(prt, F_TRACE_SEND)) {
		trace_port_send(prt, to, mess, 1);
	    }
	    from = prt->common.id;
	}

	erts_queue_message(rp, rp_locks, factory.message, mess, from);
    }
    else if (res == -2) {
        /* this clause only happens when we were requested to
           generate a send trace, but the process to send to
           did not exist any more */
        mess = ESTACK_POP(stack);  /* get resulting value */

        trace_port_send(prt, to, mess, 0);

	erts_factory_trim_and_close(&factory, &mess, 1);
        erts_free(ERTS_ALC_T_DRIVER, factory.hp_start);
        res = 0;
    }
    else {
	if (b2t.ix > b2t.used)
	    b2t.used = b2t.ix;
	for (b2t.ix = 0; b2t.ix < b2t.used; b2t.ix++)
	    erts_binary2term_abort(&b2t.state[b2t.ix]);
        if (factory.mode != FACTORY_CLOSED) {
            ERL_MESSAGE_TERM(factory.message) = am_undefined;
            erts_factory_undo(&factory);
        }
    }
    if (rp) {
	if (rp_locks)
	    erts_proc_unlock(rp, rp_locks);
	if (!scheduler)
	    erts_proc_dec_refc(rp);
    }
    cleanup_b2t_states(&b2t);
    DESTROY_ESTACK(stack);
    return res;
#undef ERTS_DDT_FAIL
#undef HEAP_EXTRA
}

static ERTS_INLINE int
deliver_term_check_port(ErlDrvTermData port_id, Eterm *connected_p,
                        Port **trace_prt)
{
    ErtsThrPrgrDelayHandle dhndl = erts_thr_progress_unmanaged_delay();
    erts_aint32_t state;
    int res = 1;
    Port *prt = erts_port_lookup_raw((Eterm) port_id);
    if (!prt) {
	res = -1;
	goto done;
    }
    state = erts_atomic32_read_nob(&prt->state);
    if (state & (ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP
		 | ERTS_PORT_SFLG_CLOSING)) {
	if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
	    res = -1;
	else
	    res = 0;
	goto done;
    }
    if (connected_p) {
	if (dhndl != ERTS_THR_PRGR_DHANDLE_MANAGED)
	    ETHR_MEMBAR(ETHR_LoadLoad);
	*connected_p = ERTS_PORT_GET_CONNECTED(prt);
    }

done:

    if (dhndl != ERTS_THR_PRGR_DHANDLE_MANAGED) {
	ERTS_LC_ASSERT(!prt || !erts_lc_is_port_locked(prt));
	erts_thr_progress_unmanaged_continue(dhndl);
	ETHR_MEMBAR(ETHR_LoadLoad|ETHR_LoadStore);
    } else
    if (res == 1) {
	ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
        *trace_prt = prt;
    }
    return res;
}

int erl_drv_output_term(ErlDrvTermData port_id, ErlDrvTermData* data, int len)
{
    /* May be called from arbitrary thread */
    Eterm connected = NIL; /* Shut up faulty warning... */
    Port *prt = NULL;
    int res = deliver_term_check_port(port_id, &connected, &prt);
    if (res <= 0)
	return res;
    return driver_deliver_term(prt, connected, data, len);
}

/*
 * driver_output_term() is deprecated, and has been scheduled for
 * removal in OTP-R17. It is replaced by erl_drv_output_term()
 * above.
 */
int 
driver_output_term(ErlDrvPort drvport, ErlDrvTermData* data, int len)
{
    erts_aint32_t state;
    Port* prt;

    ERTS_CHK_NO_PROC_LOCKS;
    /* NOTE! It *not* safe to access 'drvport' from unmanaged threads. */
    prt = erts_drvport2port_state(drvport, &state);
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return -1; /* invalid (dead) */
    ERTS_CHK_NO_PROC_LOCKS;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
    if (state & ERTS_PORT_SFLG_CLOSING)
	return 0;

    return driver_deliver_term(prt, ERTS_PORT_GET_CONNECTED(prt), data, len);
}

int erl_drv_send_term(ErlDrvTermData port_id,
		      ErlDrvTermData to,
		      ErlDrvTermData* data,
		      int len)
{
    /* May be called from arbitrary thread */
    Port *prt = NULL;
    int res = deliver_term_check_port(port_id, NULL, &prt);
    if (res <= 0)
	return res;
    return driver_deliver_term(prt, to, data, len);
}

/*
 * driver_send_term() is deprecated, and has been scheduled for
 * removal in OTP-R17. It is replaced by erl_drv_send_term() above.
 */
int
driver_send_term(ErlDrvPort drvport,
		 ErlDrvTermData to,
		 ErlDrvTermData* data,
		 int len)
{
    /*
     * NOTE! It is *not* safe to access the 'drvport' parameter
     * from unmanaged threads. Also note that it is impossible
     * to make this access safe without using a less efficient
     * internal data representation for ErlDrvPort.
     */
    Port* prt = NULL;
    ERTS_CHK_NO_PROC_LOCKS;
    if (erts_thr_progress_is_managed_thread())
    {
	erts_aint32_t state;
	prt = erts_drvport2port_state(drvport, &state);
	if (prt == ERTS_INVALID_ERL_DRV_PORT)
	    return -1; /* invalid (dead) */
	ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
	if (state & ERTS_PORT_SFLG_CLOSING)
	    return 0;
    }
    return driver_deliver_term(prt, to, data, len);
}


/*
 * Output a binary with hlen bytes from hbuf as list header
 * and data is len length of bin starting from offset offs.
 */

int driver_output_binary(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
			 ErlDrvBinary* bin, ErlDrvSizeT offs, ErlDrvSizeT len)
{
    erts_aint32_t state;
    Port* prt = erts_drvport2port_state(ix, &state);
    ErtsSchedulerData *esdp = erts_get_scheduler_data();

    ERTS_CHK_NO_PROC_LOCKS;

    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return -1;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
    if (state & ERTS_PORT_SFLG_CLOSING)
	return 0;

    prt->bytes_in += (hlen + len);
    if (esdp)
	esdp->io.in += (Uint64) (hlen + len);
    else
	erts_atomic64_add_nob(&bytes_in, (erts_aint64_t) (hlen + len));
    if (state & ERTS_PORT_SFLG_DISTRIBUTION) {
        DistEntry* dep = (DistEntry*) erts_prtsd_get(prt, ERTS_PRTSD_DIST_ENTRY);
        Uint32 conn_id = (Uint32)(UWord) erts_prtsd_get(prt, ERTS_PRTSD_CONN_ID);
        erts_atomic64_inc_nob(&dep->in);
	return erts_net_message(prt,
				dep,
                                conn_id,
				(byte*) hbuf, hlen,
                                ErlDrvBinary2Binary(bin),
				(byte*) (bin->orig_bytes+offs), len);
    }
    else
	deliver_bin_message(prt, ERTS_PORT_GET_CONNECTED(prt), 
			    hbuf, hlen, bin, offs, len);
    return 0;
}

/* driver_output2:
** Delivers hlen bytes from hbuf to the port owner as a list;
** after that, the port settings apply, buf is sent as binary or list.
**
** Example: if hlen = 3 then the port owner will receive the data
** [H1,H2,H3 | T]
*/
int driver_output2(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
		   char* buf, ErlDrvSizeT len)
{
    erts_aint32_t state;
    Port* prt = erts_drvport2port_state(ix, &state);
    ErtsSchedulerData *esdp = erts_get_scheduler_data();

    ERTS_CHK_NO_PROC_LOCKS;

    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return -1;

    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
    if (state & ERTS_PORT_SFLG_CLOSING)
	return 0;
    
    prt->bytes_in += (hlen + len);
    if (esdp)
	esdp->io.in += (Uint64) (hlen + len);
    else
	erts_atomic64_add_nob(&bytes_in, (erts_aint64_t) (hlen + len));
    if (state & ERTS_PORT_SFLG_DISTRIBUTION) {
        DistEntry *dep = (DistEntry*) erts_prtsd_get(prt, ERTS_PRTSD_DIST_ENTRY);
        Uint32 conn_id = (Uint32)(UWord) erts_prtsd_get(prt, ERTS_PRTSD_CONN_ID);
        erts_atomic64_inc_nob(&dep->in);
	if (len == 0)
	    return erts_net_message(prt,
				    dep,
                                    conn_id,
				    NULL, 0,
                                    NULL,
				    (byte*) hbuf, hlen);
	else
	    return erts_net_message(prt,
				    dep,
                                    conn_id,
				    (byte*) hbuf, hlen,
                                    NULL,
				    (byte*) buf, len);
    }
    else if (state & ERTS_PORT_SFLG_LINEBUF_IO)
	deliver_linebuf_message(prt, state, ERTS_PORT_GET_CONNECTED(prt),
				hbuf, hlen, buf, len);
    else
	deliver_read_message(prt, state, ERTS_PORT_GET_CONNECTED(prt),
			     hbuf, hlen, buf, len, 0);
    return 0;
}

/* Interface functions available to driver writers */

int driver_output(ErlDrvPort ix, char* buf, ErlDrvSizeT len)
{
    ERTS_CHK_NO_PROC_LOCKS;
    return driver_output2(ix, NULL, 0, buf, len);
}

int driver_outputv(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
		   ErlIOVec* vec, ErlDrvSizeT skip)
{
    int n;
    ErlDrvSizeT len;
    ErlDrvSizeT size;
    SysIOVec* iov;
    ErlDrvBinary** binv;
    Port* prt;
    erts_aint32_t state;
    ErtsSchedulerData *esdp = erts_get_scheduler_data();

    ERTS_CHK_NO_PROC_LOCKS;

    ASSERT(vec->size >= skip);
    if (vec->size <= skip)
	return driver_output2(ix, hbuf, hlen, NULL, 0);
    size = vec->size - skip;   /* Size of remaining bytes in vector */

    prt = erts_drvport2port_state(ix, &state);
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return -1;

    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));

    if (state & ERTS_PORT_SFLG_CLOSING)
	return 0;

    /* size > 0 ! */
    iov = vec->iov;
    binv = vec->binv;
    n = vec->vsize;
    /* we use do here to strip iov_len=0 from beginning */
    do {
	len = iov->iov_len;
	if (len <= skip) {
	    skip -= len;
	    iov++;
	    binv++;
	    n--;
	} else {
	    iov->iov_base = ((char *)(iov->iov_base)) + skip;
	    iov->iov_len -= skip;
	    skip = 0;
	}
    } while (skip > 0);

    /* XXX handle distribution !!! */
    prt->bytes_in += (hlen + size);
    if (esdp)
	esdp->io.in += (Uint64) (hlen + size);
    else
	erts_atomic64_add_nob(&bytes_in, (erts_aint64_t) (hlen + size));
    deliver_vec_message(prt, ERTS_PORT_GET_CONNECTED(prt), hbuf, hlen,
			binv, iov, n, size);
    return 0;
}

/* Copy bytes from a vector into a buffer
** input is a vector a buffer and a max length
** return bytes copied
*/
ErlDrvSizeT driver_vec_to_buf(ErlIOVec *vec, char *buf, ErlDrvSizeT len)
{
    SysIOVec* iov = vec->iov;
    int n = vec->vsize;
    ErlDrvSizeT orig_len = len;

    while(n--) {
	size_t ilen = iov->iov_len;
	if (ilen < len) {
	    sys_memcpy(buf, iov->iov_base, ilen);
	    len -= ilen;
	    buf += ilen;
	    iov++;
	}
	else {
	    sys_memcpy(buf, iov->iov_base, len);
	    return orig_len;
	}
    }
    return (orig_len - len);
}

/*
 * reference count on driver binaries...
 */

ErlDrvSInt
driver_binary_get_refc(ErlDrvBinary *dbp)
{
    Binary* bp = ErlDrvBinary2Binary(dbp);
    return (ErlDrvSInt) erts_refc_read(&bp->intern.refc, 1);
}

ErlDrvSInt
driver_binary_inc_refc(ErlDrvBinary *dbp)
{
    Binary* bp = ErlDrvBinary2Binary(dbp);
    return (ErlDrvSInt) erts_refc_inctest(&bp->intern.refc, 2);
}

ErlDrvSInt
driver_binary_dec_refc(ErlDrvBinary *dbp)
{
    Binary* bp = ErlDrvBinary2Binary(dbp);
    return (ErlDrvSInt) erts_refc_dectest(&bp->intern.refc, 1);
}


/*
** Allocation/Deallocation of binary objects 
*/

ErlDrvBinary*
driver_alloc_binary(ErlDrvSizeT size)
{
    Binary* bin;

    bin = erts_bin_drv_alloc_fnf((Uint) size);
    if (!bin)
	return NULL; /* The driver write must take action */
    return Binary2ErlDrvBinary(bin);
}

/* Reallocate space held by binary */

ErlDrvBinary* driver_realloc_binary(ErlDrvBinary* bin, ErlDrvSizeT size)
{
    Binary* oldbin;
    Binary* newbin;

    if (!bin)
	return driver_alloc_binary(size);

    oldbin = ErlDrvBinary2Binary(bin);
    newbin = (Binary *) erts_bin_realloc_fnf(oldbin, size);
    if (!newbin)
	return NULL;

    return Binary2ErlDrvBinary(newbin);
}


void driver_free_binary(ErlDrvBinary* dbin)
{
    Binary *bin;
    if (!dbin)
	return;

    bin = ErlDrvBinary2Binary(dbin);
    erts_bin_release(bin);
}


/* 
 * Allocation/deallocation of memory for drivers 
 */

void *driver_alloc(ErlDrvSizeT size)
{
    return erts_alloc_fnf(ERTS_ALC_T_DRV, (Uint) size);
}

void *driver_realloc(void *ptr, ErlDrvSizeT size)
{
    return erts_realloc_fnf(ERTS_ALC_T_DRV, ptr, (Uint) size);
}

void driver_free(void *ptr)
{
    erts_free(ERTS_ALC_T_DRV, ptr);
}

/*
 * Port Data Lock
 */

static void
pdl_init(void)
{
}

static ERTS_INLINE void
pdl_init_refc(ErlDrvPDL pdl)
{
    erts_atomic_init_nob(&pdl->refc, 1);
}

static ERTS_INLINE ErlDrvSInt
pdl_read_refc(ErlDrvPDL pdl)
{
    erts_aint_t refc = erts_atomic_read_nob(&pdl->refc);
    ERTS_LC_ASSERT(refc >= 0);
    return (ErlDrvSInt) refc;
}

static ERTS_INLINE void
pdl_inc_refc(ErlDrvPDL pdl)
{
    erts_atomic_inc_nob(&pdl->refc);
    ERTS_LC_ASSERT(driver_pdl_get_refc(pdl) > 1);
}

static ERTS_INLINE ErlDrvSInt
pdl_inctest_refc(ErlDrvPDL pdl)
{
    erts_aint_t refc = erts_atomic_inc_read_nob(&pdl->refc);
    ERTS_LC_ASSERT(refc > 1);
    return (ErlDrvSInt) refc;
}

#if 0 /* unused */
static ERTS_INLINE void
pdl_dec_refc(ErlDrvPDL pdl)
{
    erts_atomic_dec_nob(&pdl->refc);
    ERTS_LC_ASSERT(driver_pdl_get_refc(pdl) > 0);
}
#endif

static ERTS_INLINE ErlDrvSInt
pdl_dectest_refc(ErlDrvPDL pdl)
{
    erts_aint_t refc = erts_atomic_dec_read_nob(&pdl->refc);
    ERTS_LC_ASSERT(refc >= 0);
    return (ErlDrvSInt) refc;
}

static ERTS_INLINE void pdl_destroy(ErlDrvPDL pdl)
{
    ERTS_LC_ASSERT(driver_pdl_get_refc(pdl) == 0);
    erts_mtx_destroy(&pdl->mtx);
    erts_port_dec_refc(pdl->prt);
    erts_free(ERTS_ALC_T_PORT_DATA_LOCK, pdl);
}


static void driver_monitor_lock_pdl(Port *p) {
    if (p->port_data_lock) {
	driver_pdl_lock(p->port_data_lock);
    }
    /* Now we either have the port lock or the port_data_lock */
    ERTS_LC_ASSERT(!p->port_data_lock
		   || erts_lc_mtx_is_locked(&(p->port_data_lock->mtx)));
    ERTS_LC_ASSERT(p->port_data_lock
		       || erts_lc_is_port_locked(p));
}

static void driver_monitor_unlock_pdl(Port *p) {
    /* We should either have the port lock or the port_data_lock */
    ERTS_LC_ASSERT(!p->port_data_lock
		   || erts_lc_mtx_is_locked(&(p->port_data_lock->mtx)));
    ERTS_LC_ASSERT(p->port_data_lock
		       || erts_lc_is_port_locked(p));
    if (p->port_data_lock) {
	driver_pdl_unlock(p->port_data_lock);
    }
}


/*
 * exported driver_pdl_* functions ...
 */

ErlDrvPDL
driver_pdl_create(ErlDrvPort dp)
{
    ErlDrvPDL pdl;
    Port *pp = erts_drvport2port(dp);
    if (pp == ERTS_INVALID_ERL_DRV_PORT || pp->port_data_lock)
	return NULL;
    pdl = erts_alloc(ERTS_ALC_T_PORT_DATA_LOCK,
		     sizeof(struct erl_drv_port_data_lock));
    erts_mtx_init(&pdl->mtx, "port_data_lock", pp->common.id, ERTS_LOCK_FLAGS_CATEGORY_IO);
    pdl_init_refc(pdl);
    erts_port_inc_refc(pp);
    pdl->prt = pp;
    pp->port_data_lock = pdl;
#ifdef HARDDEBUG
    erts_fprintf(stderr, "driver_pdl_create(%T) -> 0x%08X\r\n",pp->common.id,(unsigned) pdl);
#endif
    return pdl;
}

void
driver_pdl_lock(ErlDrvPDL pdl)
{
#ifdef HARDDEBUG
    erts_fprintf(stderr, "driver_pdl_lock(0x%08X)\r\n",(unsigned) pdl);
#endif
    pdl_inc_refc(pdl);
    erts_mtx_lock(&pdl->mtx);
}

void
driver_pdl_unlock(ErlDrvPDL pdl)
{
    ErlDrvSInt refc;
#ifdef HARDDEBUG
    erts_fprintf(stderr, "driver_pdl_unlock(0x%08X)\r\n",(unsigned) pdl);
#endif
    erts_mtx_unlock(&pdl->mtx);
    refc = pdl_dectest_refc(pdl);
    if (!refc)
	pdl_destroy(pdl);
}

ErlDrvSInt
driver_pdl_get_refc(ErlDrvPDL pdl)
{
    return pdl_read_refc(pdl);
}

ErlDrvSInt
driver_pdl_inc_refc(ErlDrvPDL pdl)
{
    ErlDrvSInt refc = pdl_inctest_refc(pdl);
#ifdef HARDDEBUG
    erts_fprintf(stderr, "driver_pdl_inc_refc(%p) -> %bed\r\n",
		 pdl, refc);
#endif
    return refc;
}

ErlDrvSInt
driver_pdl_dec_refc(ErlDrvPDL pdl)
{
    ErlDrvSInt refc = pdl_dectest_refc(pdl);
#ifdef HARDDEBUG
    erts_fprintf(stderr, "driver_pdl_dec_refc(%p) -> %bpd\r\n",
		 pdl, refc);
#endif
    if (!refc)
	pdl_destroy(pdl);
    return refc;
}

/* Put elements from vec at q tail */
int driver_enqv(ErlDrvPort ix, ErlIOVec* vec, ErlDrvSizeT skip)
{
    ASSERT(vec->size >= skip);
    return erts_ioq_enqv(drvport2ioq(ix), (ErtsIOVec*)vec, skip);
}

/* Put elements from vec at q head */
int driver_pushqv(ErlDrvPort ix, ErlIOVec* vec, ErlDrvSizeT skip)
{
    ASSERT(vec->size >= skip);
    return erts_ioq_pushqv(drvport2ioq(ix), (ErtsIOVec*)vec, skip);
}

/*
** Remove size bytes from queue head
** Return number of bytes that remain in queue
*/
ErlDrvSizeT driver_deq(ErlDrvPort ix, ErlDrvSizeT size)
{
    ErlPortIOQueue *q = drvport2ioq(ix);
    if (erts_ioq_deq(q, size) == -1)
        return -1;
    return erts_ioq_size(q);
}


ErlDrvSizeT driver_peekqv(ErlDrvPort ix, ErlIOVec *ev)
{
    return erts_ioq_peekqv(drvport2ioq(ix), (ErtsIOVec*)ev);
}

SysIOVec* driver_peekq(ErlDrvPort ix, int* vlenp)  /* length of io-vector */
{
    return erts_ioq_peekq(drvport2ioq(ix), vlenp);
}


ErlDrvSizeT driver_sizeq(ErlDrvPort ix)
{
    ErlPortIOQueue *q = drvport2ioq(ix);

    if (q == NULL)
	return (ErlDrvSizeT) -1;
    return erts_ioq_size(q);
}


/* Utils */

/* Enqueue a binary */
int driver_enq_bin(ErlDrvPort ix, ErlDrvBinary* bin,
		   ErlDrvSizeT offs, ErlDrvSizeT len)
{
    SysIOVec      iov;
    ErlIOVec      ev;

    ASSERT(len >= 0);
    if (len == 0)
	return 0;
    iov.iov_base = bin->orig_bytes + offs;
    iov.iov_len  = len;
    ev.vsize = 1;
    ev.size = len;
    ev.iov = &iov;
    ev.binv = &bin;
    return driver_enqv(ix, &ev, 0);
}

int driver_enq(ErlDrvPort ix, char* buffer, ErlDrvSizeT len)
{
    int code;
    ErlDrvBinary* bin;

    ASSERT(len >= 0);
    if (len == 0)
	return 0;
    if ((bin = driver_alloc_binary(len)) == NULL)
	return -1;
    sys_memcpy(bin->orig_bytes, buffer, len);
    code = driver_enq_bin(ix, bin, 0, len);
    driver_free_binary(bin);  /* dereference */
    return code;
}

int driver_pushq_bin(ErlDrvPort ix, ErlDrvBinary* bin,
		     ErlDrvSizeT offs, ErlDrvSizeT len)
{
    SysIOVec      iov;
    ErlIOVec      ev;

    ASSERT(len >= 0);
    if (len == 0)
	return 0;
    iov.iov_base = bin->orig_bytes + offs;
    iov.iov_len  = len;
    ev.vsize = 1;
    ev.size = len;
    ev.iov = &iov;
    ev.binv = &bin;
    return driver_pushqv(ix, &ev, 0);
}

int driver_pushq(ErlDrvPort ix, char* buffer, ErlDrvSizeT len)
{
    int code;
    ErlDrvBinary* bin;

    ASSERT(len >= 0);
    if (len == 0)
	return 0;

    if ((bin = driver_alloc_binary(len)) == NULL)
	return -1;
    sys_memcpy(bin->orig_bytes, buffer, len);
    code = driver_pushq_bin(ix, bin, 0, len);
    driver_free_binary(bin);  /* dereference */
    return code;
}

int driver_set_timer(ErlDrvPort ix, unsigned long t)
{
    Port* prt = erts_drvport2port(ix);

    ERTS_CHK_NO_PROC_LOCKS;

    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return -1;

    if (prt->drv_ptr->timeout == NULL)
	return -1;

    erts_set_port_timer(prt, (Sint64) t);
    return 0;
}

int driver_cancel_timer(ErlDrvPort ix)
{
    Port* prt = erts_drvport2port(ix);
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return -1;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
    erts_cancel_port_timer(prt);
    return 0;
}

int
driver_read_timer(ErlDrvPort ix, unsigned long* t)
{
    Port* prt = erts_drvport2port(ix);
    Sint64 left;

    ERTS_CHK_NO_PROC_LOCKS;

    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return -1;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));

    left = erts_read_port_timer(prt);
    if (left < 0)
	left = 0;

    *t = (unsigned long) left;

    return 0;
}

int 
driver_get_now(ErlDrvNowData *now_data)
{
    Uint mega,secs,micro;
    ERTS_CHK_NO_PROC_LOCKS;

    if (now_data == NULL) {
	return -1;
    }
    get_now(&mega,&secs,&micro);
    now_data->megasecs = (unsigned long) mega;
    now_data->secs = (unsigned long) secs;
    now_data->microsecs = (unsigned long) micro;
    return 0;
}

ErlDrvTime
erl_drv_monotonic_time(ErlDrvTimeUnit time_unit)
{
    return (ErlDrvTime) erts_napi_monotonic_time((int) time_unit);
}

ErlDrvTime
erl_drv_time_offset(ErlDrvTimeUnit time_unit)
{
    return (ErlDrvTime) erts_napi_time_offset((int) time_unit);
}

ErlDrvTime
erl_drv_convert_time_unit(ErlDrvTime val,
			  ErlDrvTimeUnit from,
			  ErlDrvTimeUnit to)
{
    return (ErlDrvTime) erts_napi_convert_time_unit((ErtsMonotonicTime) val,
						    (int) from,
						    (int) to);
}

void erts_ref_to_driver_monitor(Eterm ref, ErlDrvMonitor *mon)
{
    ERTS_CT_ASSERT(ERTS_REF_THING_SIZE*sizeof(Uint) <= sizeof(ErlDrvMonitor));
    ASSERT(is_internal_ordinary_ref(ref));
    sys_memcpy((void *) mon, (void *) internal_ref_val(ref),
               ERTS_REF_THING_SIZE*sizeof(Uint));
}

Eterm erts_driver_monitor_to_ref(Eterm *hp, const ErlDrvMonitor *mon)
{
    Eterm ref;
    ERTS_CT_ASSERT(ERTS_REF_THING_SIZE*sizeof(Uint) <= sizeof(ErlDrvMonitor));
    sys_memcpy((void *) hp, (void *) mon, ERTS_REF_THING_SIZE*sizeof(Uint));
    ref = make_internal_ref(hp);
    ASSERT(is_internal_ordinary_ref(ref));
    return ref;
}

static int do_driver_monitor_process(Port *prt,
				     ErlDrvTermData process,
				     ErlDrvMonitor *monitor)
{
    Eterm buf[ERTS_REF_THING_SIZE];
    Eterm ref;
    ErtsMonitorData *mdp;

    if (!prt->drv_ptr->process_exit)
	return -1;

    ref = erts_make_ref_in_buffer(buf);
    mdp = erts_monitor_create(ERTS_MON_TYPE_PORT, ref,
                              prt->common.id, process, NIL,
                              THE_NON_VALUE);

    if (!erts_proc_sig_send_monitor(&prt->common, prt->common.id,
                                    &mdp->u.target, process)) {
        erts_monitor_release_both(mdp);
        return 1;
    }

    erts_monitor_tree_insert(&ERTS_P_MONITORS(prt), &mdp->origin);

    erts_ref_to_driver_monitor(ref,monitor);
    return 0;
}

/*
 * This can be called from a non scheduler thread iff a port_data_lock exists
 */
int driver_monitor_process(ErlDrvPort drvport,
			   ErlDrvTermData process,
			   ErlDrvMonitor *monitor)
{
    Port *prt;
    int ret;
#if defined(ERTS_ENABLE_LOCK_CHECK)
    ErtsSchedulerData *sched = erts_get_scheduler_data();
#endif

    prt = DRV_MONITOR_LOOKUP_PORT_LOCK_PDL(drvport);
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return -1;

    /* Now (in SMP) we should have either the port lock (if we have a scheduler) or the port data lock
       (if we're a driver thread) */
    ERTS_LC_ASSERT((sched != NULL || prt->port_data_lock));
    ret = do_driver_monitor_process(prt,process,monitor);
    DRV_MONITOR_UNLOCK_PDL(prt);
    return ret;
}

static int do_driver_demonitor_process(Port *prt, const ErlDrvMonitor *monitor)
{
    Eterm heap[ERTS_REF_THING_SIZE];
    Eterm ref;
    ErtsMonitor *mon;

    ref = erts_driver_monitor_to_ref(heap, monitor);

    mon = erts_monitor_tree_lookup(ERTS_P_MONITORS(prt), ref);
    if (!mon || !erts_monitor_is_origin(mon))
        return 1;

    erts_monitor_tree_delete(&ERTS_P_MONITORS(prt), mon);
    erts_proc_sig_send_demonitor(&prt->common, prt->common.id, 0, mon);

    return 0;
}

int driver_demonitor_process(ErlDrvPort drvport,
			     const ErlDrvMonitor *monitor)
{
    Port *prt;
    int ret;
#if defined(ERTS_ENABLE_LOCK_CHECK)
    ErtsSchedulerData *sched = erts_get_scheduler_data();
#endif

    prt = DRV_MONITOR_LOOKUP_PORT_LOCK_PDL(drvport);
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return -1;

    /* Now we should have either the port lock (if we have a scheduler) or the port data lock
       (if we're a driver thread) */
    ERTS_LC_ASSERT((sched != NULL || prt->port_data_lock));
    ret = do_driver_demonitor_process(prt,monitor);
    DRV_MONITOR_UNLOCK_PDL(prt);
    return ret;
}

static ErlDrvTermData do_driver_get_monitored_process(Port *prt,const ErlDrvMonitor *monitor)
{
    Eterm ref;
    ErtsMonitor *mon;
    Eterm heap[ERTS_REF_THING_SIZE];

    ref = erts_driver_monitor_to_ref(heap, monitor);

    mon = erts_monitor_tree_lookup(ERTS_P_MONITORS(prt), ref);
    if (!mon || !erts_monitor_is_origin(mon))
	return driver_term_nil;

    ASSERT(is_internal_pid(mon->other.item));
    return (ErlDrvTermData) mon->other.item;
}


ErlDrvTermData driver_get_monitored_process(ErlDrvPort drvport,
					    const ErlDrvMonitor *monitor)
{
    Port *prt;
    ErlDrvTermData ret;
#if defined(ERTS_ENABLE_LOCK_CHECK)
    ErtsSchedulerData *sched = erts_get_scheduler_data();
#endif

    prt = DRV_MONITOR_LOOKUP_PORT_LOCK_PDL(drvport);
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return driver_term_nil;

    /* Now we should have either the port lock (if we have a scheduler) or the port data lock
       (if we're a driver thread) */
    ERTS_LC_ASSERT((sched != NULL || prt->port_data_lock));
    ret = do_driver_get_monitored_process(prt,monitor);
    DRV_MONITOR_UNLOCK_PDL(prt);
    return ret;
}

int driver_compare_monitors(const ErlDrvMonitor *monitor1,
			    const ErlDrvMonitor *monitor2)
{
    return sys_memcmp((void *) monitor1, (void *) monitor2,
                      ERTS_REF_THING_SIZE*sizeof(Eterm));
}

void erts_fire_port_monitor(Port *prt, ErtsMonitor *tmon)
{
    ErtsMonitorData *mdp;
    void (*callback)(ErlDrvData drv_data, ErlDrvMonitor *monitor);
    ErlDrvMonitor drv_monitor;
    ERTS_MSACC_PUSH_STATE_M();

    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
    ASSERT(prt->drv_ptr != NULL);
    ASSERT(erts_monitor_is_target(tmon));
    mdp = erts_monitor_to_data(tmon);
    DRV_MONITOR_LOCK_PDL(prt);
    if (!erts_monitor_is_in_table(&mdp->origin)) {
	DRV_MONITOR_UNLOCK_PDL(prt);
        erts_monitor_release(tmon);
	return;
    }
    callback = prt->drv_ptr->process_exit;
    ASSERT(callback != NULL);
    erts_ref_to_driver_monitor(mdp->ref,&drv_monitor);
    ERTS_MSACC_SET_STATE_CACHED_M(ERTS_MSACC_STATE_PORT);
    DRV_MONITOR_UNLOCK_PDL(prt);
#ifdef USE_VM_PROBES
    if (DTRACE_ENABLED(driver_process_exit)) {
        DTRACE_FORMAT_COMMON_PID_AND_PORT(ERTS_PORT_GET_CONNECTED(prt), prt)
        DTRACE3(driver_process_exit, process_str, port_str, prt->name);
    }
#endif
#ifdef USE_LTTNG_VM_TRACEPOINTS
    if (LTTNG_ENABLED(driver_process_exit)) {
        lttng_decl_portbuf(port_str);
        lttng_decl_procbuf(proc_str);
        lttng_pid_to_str(ERTS_PORT_GET_CONNECTED(prt), proc_str);
        lttng_port_to_str(prt, port_str);
        LTTNG3(driver_process_exit, proc_str, port_str, prt->name);
    }
#endif
    (*callback)((ErlDrvData) (prt->drv_data), &drv_monitor);
    DRV_MONITOR_LOCK_PDL(prt);
    ERTS_MSACC_POP_STATE_M();
    /* remove monitor *after* callback */
    erts_monitor_tree_delete(&ERTS_P_MONITORS(prt), &mdp->origin);
    DRV_MONITOR_UNLOCK_PDL(prt);
    erts_monitor_release_both(mdp);
}


static int
driver_failure_term(ErlDrvPort ix, Eterm term, int eof)
{
    erts_aint32_t state;
    Port* prt = erts_drvport2port_state(ix, &state);

    ERTS_CHK_NO_PROC_LOCKS;

    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return -1;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));

    if (prt->async_open_port)
        init_ack_send_reply(prt, prt->common.id);
    if (eof)
	flush_linebuf_messages(prt, state);
    if (state & ERTS_PORT_SFLG_CLOSING) {
	terminate_port(prt);
    } else if (eof && (state & ERTS_PORT_SFLG_SOFT_EOF)) {
	deliver_result(prt, prt->common.id, ERTS_PORT_GET_CONNECTED(prt), am_eof);
    } else {
	/* XXX UGLY WORK AROUND, Let erts_deliver_port_exit() terminate the port */
	if (prt->port_data_lock)
	    driver_pdl_lock(prt->port_data_lock);
	prt->ioq.size = 0;
	if (prt->port_data_lock)
	    driver_pdl_unlock(prt->port_data_lock);
	erts_deliver_port_exit(prt, prt->common.id, eof ? am_normal : term, 0, 0);
    }
    return 0;
}



/*
** Do a (soft) exit. unlink the connected process before doing
** driver posix error or (normal)
*/
int driver_exit(ErlDrvPort ix, int err)
{
    Port* prt = erts_drvport2port(ix);
    Eterm connected;

    ERTS_CHK_NO_PROC_LOCKS;
  
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
        return -1;

    connected = ERTS_PORT_GET_CONNECTED(prt);
    unlink_proc(prt, connected);

    if (err == 0)
        return driver_failure_term(ix, am_normal, 0);
    else {
        char* err_str = erl_errno_id(err);
        Eterm am_err = erts_atom_put((byte *) err_str, sys_strlen(err_str),
				     ERTS_ATOM_ENC_LATIN1, 1);
        return driver_failure_term(ix, am_err, 0);
    }
}


int driver_failure(ErlDrvPort ix, int code)
{
    return driver_failure_term(ix, make_small(code), code == 0);
}

int driver_failure_atom(ErlDrvPort ix, char* string)
{
    return driver_failure_term(ix,
			       erts_atom_put((byte *) string,
					     sys_strlen(string),
					     ERTS_ATOM_ENC_LATIN1,
					     1),
			       0);
}

int driver_failure_posix(ErlDrvPort ix, int err)
{
    return driver_failure_atom(ix, erl_errno_id(err));
}

int driver_failure_eof(ErlDrvPort ix)
{
    return driver_failure_term(ix, NIL, 1);
}



ErlDrvTermData driver_mk_atom(char* string)
{
    Eterm am = erts_atom_put((byte *) string,
			     sys_strlen(string),
			     ERTS_ATOM_ENC_LATIN1,
			     1);
    ERTS_CHK_NO_PROC_LOCKS;
    return (ErlDrvTermData) am;
}

ErlDrvTermData driver_mk_port(ErlDrvPort ix)
{
    Port* prt = erts_drvport2port(ix);
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return (ErlDrvTermData) NIL;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
    return (ErlDrvTermData) prt->common.id;
}

ErlDrvTermData driver_connected(ErlDrvPort ix)
{
    Port* prt = erts_drvport2port(ix);
    ERTS_CHK_NO_PROC_LOCKS;
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return NIL;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
    return ERTS_PORT_GET_CONNECTED(prt);
}

ErlDrvTermData driver_caller(ErlDrvPort ix)
{
    Port* prt = erts_drvport2port(ix);
    ERTS_CHK_NO_PROC_LOCKS;
    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return NIL;
    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
    return prt->caller;
}

int driver_lock_driver(ErlDrvPort ix)
{
    Port* prt = erts_drvport2port(ix);
    DE_Handle* dh;

    ERTS_CHK_NO_PROC_LOCKS;

    if (prt == ERTS_INVALID_ERL_DRV_PORT)
	return -1;

    erts_rwmtx_rwlock(&erts_driver_list_lock);

    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
    if ((dh = (DE_Handle*)prt->drv_ptr->handle ) == NULL) {
	erts_rwmtx_rwunlock(&erts_driver_list_lock);
	return -1;
    }
    erts_ddll_lock_driver(dh, prt->drv_ptr->name);
    erts_rwmtx_rwunlock(&erts_driver_list_lock);
    return 0;
}


static int maybe_lock_driver_list(void) 
{
    void *rec_lock;
    rec_lock = erts_tsd_get(driver_list_lock_status_key);
    if (rec_lock == 0) {
	erts_rwmtx_rwlock(&erts_driver_list_lock);
	return 1;
    }
    return 0;
}
static void maybe_unlock_driver_list(int doit)
{
    if (doit) {
	erts_rwmtx_rwunlock(&erts_driver_list_lock);
    }
}
/* 
   These old interfaces are certainly not MT friendly. Hopefully they are only used internally,
   but you never know, so they are kept for BC. As The sys ddll code has no notion
   of locking, I use the driver list lock to mutex this from the code in erl_bif_ddll.c.
   To allow dynamic code loading in the init functions of a driver, recursive locking is 
   handled as in add_driver_entry etc.
   A TSD variable holds the last error for a thread, so that code like
   ...
   x = driver_dl_open(...);
   if (x == NULL)
      y = driver_dl_error();
   ...
   works as long as execution happens in one driver callback even in an SMP emulator. 
   Writing code using these interfaces spanning several driver callbacks between loading/lookup 
   and error handling may give undesired results...
*/
void *driver_dl_open(char * path)
{
    void *ptr;
    int res;
    int *last_error_p = erts_tsd_get(driver_list_last_error_key);
    int locked = maybe_lock_driver_list();
    if ((res = erts_sys_ddll_open(path, &ptr, NULL)) == 0) {
	maybe_unlock_driver_list(locked);
	return ptr;
    } else {
	if (!last_error_p) {
	    last_error_p = erts_alloc(ERTS_ALC_T_DDLL_ERRCODES, sizeof(int));
	    erts_tsd_set(driver_list_last_error_key,last_error_p);
	}
	*last_error_p = res;
	maybe_unlock_driver_list(locked);
	return NULL;
    }
}

void *driver_dl_sym(void * handle, char *func_name)
{
    void *ptr;
    int res;
    int *last_error_p = erts_tsd_get(driver_list_lock_status_key);
    int locked = maybe_lock_driver_list();
    if ((res = erts_sys_ddll_sym(handle, func_name, &ptr)) == 0) {
	maybe_unlock_driver_list(locked);
	return ptr;
    } else {
	if (!last_error_p) {
	    last_error_p = erts_alloc(ERTS_ALC_T_DDLL_ERRCODES, sizeof(int));
	    erts_tsd_set(driver_list_lock_status_key,last_error_p);
	}
	*last_error_p = res;
	maybe_unlock_driver_list(locked);
	return NULL;
    }
}
    
int driver_dl_close(void *handle)
{
    int res;
    int locked = maybe_lock_driver_list();
    res = erts_sys_ddll_close(handle);
    maybe_unlock_driver_list(locked);
    return res;
}

char *driver_dl_error(void) 
{
    char *res;
    int *last_error_p = erts_tsd_get(driver_list_lock_status_key);
    int locked = maybe_lock_driver_list();
    res = erts_ddll_error((last_error_p != NULL) ? (*last_error_p) : ERL_DE_ERROR_UNSPECIFIED); 
    maybe_unlock_driver_list(locked);
    return res;
}


#define ERL_DRV_SYS_INFO_SIZE(LAST_FIELD) \
  (offsetof(ErlDrvSysInfo, LAST_FIELD) \
   + sizeof(((ErlDrvSysInfo *) 0)->LAST_FIELD))

void
driver_system_info(ErlDrvSysInfo *sip, size_t si_size)
{
    /*
     * When adding fields in the ErlDrvSysInfo struct
     * remember to increment ERL_DRV_EXTENDED_MINOR_VERSION
     */

    /*
     * 'smp_support' is the last field in the first version
     * of ErlDrvSysInfo (introduced in driver version 1.0).
     */
    if (!sip || si_size < ERL_DRV_SYS_INFO_SIZE(smp_support)) 
	erts_exit(ERTS_ERROR_EXIT,
		 "driver_system_info(%p, %ld) called with invalid arguments\n",
		 sip, si_size);

    /*
     * 'smp_support' is the last field in the first version
     * of ErlDrvSysInfo (introduced in driver version 1.0).
     */
    if (si_size >= ERL_DRV_SYS_INFO_SIZE(smp_support)) {
	sip->driver_major_version = ERL_DRV_EXTENDED_MAJOR_VERSION;
	sip->driver_minor_version = ERL_DRV_EXTENDED_MINOR_VERSION;
	sip->erts_version = ERLANG_VERSION;
	sip->otp_release = ERLANG_OTP_RELEASE;
	sip->thread_support = 1;
	sip->smp_support = 1;

    }

    /*
     * 'scheduler_threads' is the last field in the second version
     * of ErlDrvSysInfo (introduced in driver version 1.1).
     */
    if (si_size >= ERL_DRV_SYS_INFO_SIZE(scheduler_threads)) {
	sip->async_threads = erts_async_max_threads;
	sip->scheduler_threads = erts_no_schedulers;
    }
    /*
     * 'nif_minor_version' is the last field in the third version
     * (driver version 1.5, NIF version 1.0) 
     */
    if (si_size >= ERL_DRV_SYS_INFO_SIZE(nif_minor_version)) {
	sip->nif_major_version = ERL_NIF_MAJOR_VERSION;
	sip->nif_minor_version = ERL_NIF_MINOR_VERSION;
    }
    /*
     * 'dirty_scheduler_support' is the last field in the 4th version
     * (driver version 3.1, NIF version 2.7)
     */
    if (si_size >= ERL_DRV_SYS_INFO_SIZE(dirty_scheduler_support)) {
	sip->dirty_scheduler_support =
	    1
	    ;
    }

}


static ERTS_INLINE Port *
get_current_port(void)
{
    ErtsSchedulerData *esdp = erts_get_scheduler_data();
    ASSERT(esdp);
    ASSERT(esdp->current_port);
    return esdp->current_port;
}

/*
 * Default callbacks used if not supplied by driver.
 */

static void
no_output_callback(ErlDrvData drv_data, char *buf, ErlDrvSizeT len)
{

}

static void
no_ready_input_callback(ErlDrvData drv_data, ErlDrvEvent event)
{
    Port *prt = get_current_port();
    report_missing_drv_callback(prt, "Input", "ready_input()");
    driver_select(ERTS_Port2ErlDrvPort(prt), event, 
		  (ERL_DRV_READ | ERL_DRV_USE_NO_CALLBACK), 0);
}

static void
no_ready_output_callback(ErlDrvData drv_data, ErlDrvEvent event)
{
    Port *prt = get_current_port();
    report_missing_drv_callback(prt, "Output", "ready_output()");
    driver_select(ERTS_Port2ErlDrvPort(prt), event,
		  (ERL_DRV_WRITE | ERL_DRV_USE_NO_CALLBACK), 0);
}

static void
no_timeout_callback(ErlDrvData drv_data)
{

}

static void
no_stop_select_callback(ErlDrvEvent event, void* private)
{
    erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();    
    erts_dsprintf(dsbufp, "Driver does not implement stop_select callback "
			  "(event=%ld, private=%p)!\n", (long)event, private);
    erts_send_error_to_logger_nogl(dsbufp);
}

#define IS_DRIVER_VERSION_GE(DE,MAJOR,MINOR) \
    ((DE)->major_version > (MAJOR) ||        \
     ((DE)->major_version == (MAJOR) && (DE)->minor_version >= (MINOR)))

static int
init_driver(erts_driver_t *drv, ErlDrvEntry *de, DE_Handle *handle)
{
    drv->name_atom = erts_atom_put((byte*)de->driver_name,
                                   sys_strlen(de->driver_name),
                                   ERTS_ATOM_ENC_LATIN1, 1);
    drv->name = de->driver_name;

    ASSERT(de->extended_marker == ERL_DRV_EXTENDED_MARKER);
    ASSERT(de->major_version >= 2);
    drv->version.major = de->major_version;
    drv->version.minor = de->minor_version;
    drv->flags = de->driver_flags;
    drv->handle = handle;
    if (drv->flags & ERL_DRV_FLAG_USE_PORT_LOCKING) {
        drv->lock = NULL;
    } else {
        drv->lock = erts_alloc(ERTS_ALC_T_DRIVER_LOCK, sizeof(erts_mtx_t));

        erts_mtx_init(drv->lock, "driver_lock", drv->name_atom,
                      ERTS_LOCK_FLAGS_CATEGORY_IO);
    }
    drv->entry = de;

    drv->start = de->start;
    drv->stop = de->stop;
    drv->finish = de->finish;
    drv->flush = de->flush;
    drv->output = de->output ? de->output : no_output_callback;
    drv->outputv = de->outputv;
    drv->control = de->control;
    drv->call = de->call;
    drv->ready_input = de->ready_input ? de->ready_input : no_ready_input_callback;
    drv->ready_output = de->ready_output ? de->ready_output : no_ready_output_callback;
    drv->timeout = de->timeout ? de->timeout : no_timeout_callback;
    drv->ready_async = de->ready_async;
    drv->process_exit = de->process_exit;
    drv->emergency_close = IS_DRIVER_VERSION_GE(de,3,2) ? de->emergency_close : NULL;
    if (de->stop_select)
	drv->stop_select = de->stop_select;
    else
	drv->stop_select = no_stop_select_callback;

    if (!de->init)
	return 0;
    else {
	int res;
        DTRACE4(driver_init, drv->name, drv->version.major, drv->version.minor,
                drv->flags);
        LTTNG4(driver_init, drv->name, drv->version.major, drv->version.minor,
                drv->flags);
	res = (*de->init)();
	return res;
    }
}

#undef IS_DRIVER_VERSION_GE

void
erts_destroy_driver(erts_driver_t *drv)
{
    if (drv->lock) {
	erts_mtx_destroy(drv->lock);
	erts_free(ERTS_ALC_T_DRIVER_LOCK, drv->lock);
    }
    erts_free(ERTS_ALC_T_DRIVER, drv);
}

/* 
 * Functions for maintaining a list of driver_entry struct
 * Exposed in the driver interface, and therefore possibly locking directly.
 */

void add_driver_entry(ErlDrvEntry *drv){
    void *rec_lock;
    rec_lock = erts_tsd_get(driver_list_lock_status_key);
    /* 
     * Ignore result of erts_add_driver_entry, the init is not
     * allowed to fail when drivers are added by drivers.
     */
    erts_add_driver_entry(drv, NULL, rec_lock != NULL, 0);
}

int erts_add_driver_entry(ErlDrvEntry *de, DE_Handle *handle,
                          int driver_list_locked, int taint)
{
    erts_driver_t *dp = erts_alloc(ERTS_ALC_T_DRIVER, sizeof(erts_driver_t));
    int err = 0;

    if (!driver_list_locked) {
	erts_rwmtx_rwlock(&erts_driver_list_lock);
    }

    dp->next = driver_list;
    dp->prev = NULL;
    if (driver_list != NULL) {
	driver_list->prev = dp;
    }
    driver_list = dp;

    if (!driver_list_locked) {
	erts_tsd_set(driver_list_lock_status_key, (void *) 1);
    }

    if (!err) {
        err = init_driver(dp, de, handle);

        if (taint) {
            erts_add_taint(dp->name_atom);
        }
    }

    if (err) {
	/* 
	 * Remove it all again...
	 */
	driver_list = dp->next;
	if (driver_list != NULL) {
	    driver_list->prev = NULL;
	}
	erts_destroy_driver(dp);
    }
	
    if (!driver_list_locked) {
	erts_tsd_set(driver_list_lock_status_key, NULL);
	erts_rwmtx_rwunlock(&erts_driver_list_lock);
    }
    return err;
}

/* Not allowed for dynamic drivers */
int remove_driver_entry(ErlDrvEntry *drv)
{
    erts_driver_t *dp;
    void *rec_lock;
    
    rec_lock = erts_tsd_get(driver_list_lock_status_key);
    if (rec_lock == NULL) {
	erts_rwmtx_rwlock(&erts_driver_list_lock);
    }
    dp = driver_list;
    while (dp && dp->entry != drv)
	dp = dp->next;
    if (dp) {
	if (dp->handle) {
	    if (rec_lock == NULL) {
		erts_rwmtx_rwunlock(&erts_driver_list_lock);
	    }
	    return -1;
	}
	if (dp->prev == NULL) {
	    driver_list = dp->next;
	} else {
	    dp->prev->next = dp->next;
	}
	if (dp->next != NULL) {
	    dp->next->prev = dp->prev;
	}
	erts_destroy_driver(dp);
	if (rec_lock == NULL) {
	    erts_rwmtx_rwunlock(&erts_driver_list_lock);
	}
	return 1;
    }
    if (rec_lock == NULL) {
	erts_rwmtx_rwunlock(&erts_driver_list_lock);
    }
    return 0;
}

/* very useful function that can be used in entries that are not used
 * so that not every driver writer must supply a personal version
 */
int null_func(void)
{
    return 0;
}

int
erl_drv_putenv(const char *key, char *value)
{
    switch (erts_sys_explicit_8bit_putenv((char*)key, value)) {
    case -1: /* Insufficient buffer space */
        return 1;
    case 1: /* Success */
        return 0;
    default: /* Not found */
        return -1;
    }
}

int
erl_drv_getenv(const char *key, char *value, size_t *value_size)
{
    switch (erts_sys_explicit_8bit_getenv((char*)key, value, value_size)) {
    case -1: /* Insufficient buffer space */
        return 1;
    case 1: /* Success */
        return 0;
    default: /* Not found */
        return -1;
    }
}

/* get heart_port
 * used by erl_crash_dump
 * - uses the fact that heart_port is registered when starting heart
 */

Port *erts_get_heart_port(void)
{
    int ix, max = erts_ptab_max(&erts_port);

    for (ix = 0; ix < max; ix++) {
	struct reg_proc *reg;
	Port *port = erts_pix2port(ix);

	if (!port)
	    continue;
	/* only examine undead or alive ports */
	if (erts_atomic32_read_nob(&port->state) & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
	    continue;
	/* immediate atom compare */
	reg = port->common.u.alive.reg;
	if (reg && reg->name == am_heart_port) {
	    return port;
	}
    }

    return NULL;
}

void erts_emergency_close_ports(void)
{
    int ix, max = erts_ptab_max(&erts_port);

    for (ix = 0; ix < max; ix++) {
	Port *port = erts_pix2port(ix);

	if (!port)
	    continue;
	/* only examine undead or alive ports */
	if (erts_atomic32_read_nob(&port->state) & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
	    continue;

	/* emergency close socket */
	if (port->drv_ptr->emergency_close) {
	    port->drv_ptr->emergency_close((ErlDrvData) port->drv_data);
	}
    }
}
