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<appref>
  <header>
    <copyright>
      <year>1996</year><year>2021</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      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.
    
    </legalnotice>

    <title>sasl</title>
    <prepared></prepared>
    <docno></docno>
    <date></date>
    <rev></rev>
    </header>
    <app>sasl</app>
    <appsummary>The SASL application</appsummary>
    <description>
    <p>The SASL application provides the following services:</p>
    <list type="bulleted">
      <item><c>alarm_handler</c></item>
      <item><c>release_handler</c></item>
      <item><c>systools</c></item>
    </list>
    <note>
       <p>The SASL application in OTP has nothing to do with
          "Simple Authentication and Security Layer" (RFC 4422).</p>
    </note>
  </description>

  <section>
    <title>Configuration</title>
    <p>The following configuration parameters are defined for the SASL
      application. For more information about configuration parameters, see
      <seefile marker="kernel:app"><c>app(4)</c></seefile> in Kernel.</p>
    <p>All configuration parameters are optional.</p>
    <taglist>
      <tag><c><![CDATA[start_prg = string() ]]></c></tag>
      <item>
        <p>Specifies the program to be used when restarting the system
          during release installation. Default is
          <c>$OTP_ROOT/bin/start</c>.</p>
      </item>
      <tag><c><![CDATA[masters = [atom()] ]]></c></tag>
      <item>
        <p>Specifies the nodes used by this node to read/write release
          information. This parameter is ignored if parameter
          <c>client_directory</c> is not set.</p>
      </item>
      <tag><c><![CDATA[client_directory = string() ]]></c></tag>
      <item>
        <p>This parameter specifies the client directory at the master
          nodes. For details, see
          <seeguide marker="system/design_principles:release_handling">Release Handling</seeguide>
          in <em>OTP Design Principles</em>. This parameter is
          ignored if parameter <c>masters</c> is not set.</p>
      </item>
      <tag><c><![CDATA[static_emulator = true | false ]]></c></tag>
      <item>
        <p>Indicates if the Erlang emulator is statically installed. A
          node with a static emulator cannot switch dynamically to a
          new emulator, as the executable files are written into memory
          statically. This parameter is ignored if parameters <c>masters</c>
          and <c>client_directory</c> are not set.</p>
      </item>
      <tag><c><![CDATA[releases_dir = string() ]]></c></tag>
      <item>
        <p>Indicates where the <c>releases</c> directory is located.
          The release handler writes all its files to this directory.
          If this parameter is not set, the OS environment parameter
          <c>RELDIR</c> is used. By default, this is
          <c>$OTP_ROOT/releases</c>.</p>
      </item>
    </taglist>
  </section>

  <section>
    <marker id="deprecated_error_logger_config"/>
    <title>Deprecated Error Logger Event Handlers and Configuration</title>
    <p>In Erlang/OTP 21.0, a new API for logging was added. The
      old <c>error_logger</c> event manager, and event handlers
      running on this manager, still work, but they are not used
      by default.</p>
    <p>The error logger event handlers <c>sasl_report_tty_h</c>
      and <c>sasl_report_file_h</c>, were earlier used for printing
      the so called SASL reports, i.e. <em>supervisor
      reports</em>, <em>crash reports</em>, and <em>progress
      reports</em>. These reports are now also printed by the default
      logger handler started by the Kernel application. Progress
      reports are by default stopped by the primary log level, but can
      be enabled by setting this level to <c>info</c>, for example by
      using the Kernel configuration
      parameter <seeapp marker="kernel:kernel_app#logger_level">
      <c>logger_level</c></seeapp>.</p>
    <p>If the old error logger event handlers are still desired, they
      must be added by
      calling <c>error_logger:add_report_handler/1,2</c>.</p>
    <taglist>
      <tag><c>sasl_report_tty_h</c></tag>
      <item>
        <p>Formats and writes <em>supervisor reports</em>, <em>crash
        reports</em>, and <em>progress reports</em> to <c>stdio</c>.
        This error logger event handler uses
	<seeapp marker="kernel:kernel_app#deprecated-configuration-parameters"><c>error_logger_format_depth</c></seeapp>
	in the Kernel application to limit how much detail is printed
	in crash and supervisor reports.</p>
      </item>
      <tag><c>sasl_report_file_h</c></tag>
      <item>
        <p>Formats and writes <em>supervisor reports</em>, <em>crash
        report</em>, and <em>progress report</em> to a single file.
        This error logger event handler uses
	<seeapp marker="kernel:kernel_app#deprecated-configuration-parameters"><c>error_logger_format_depth</c></seeapp>
	in the Kernel application to limit the details printed in
	crash and supervisor reports.</p>
      </item>
    </taglist>
    <p>A similar behaviour, but still using the new logger API, can be
      obtained by setting the Kernel application environment
      variable <seeapp marker="kernel:kernel_app#logger_sasl_compatible">
	<c>logger_sasl_compatible</c></seeapp> to <c>true</c>. This
      adds a second instance of the standard Logger handler,
      named <c>sasl</c>, which only prints the SASL reports. No SASL
      reports are then printed by the Kernel logger handler.</p>
    <p>The <c>sasl</c> handler is configured according to the values
      of the following SASL application environment variables.</p>
    <taglist>
      <tag><c><![CDATA[sasl_error_logger = Value ]]></c></tag>
      <item>
        <p><c>Value</c> is one of the following:</p>
        <taglist>
          <tag><c>tty</c></tag>
          <item><p>Installs <c>sasl_report_tty_h</c> in the error logger.
            This is the default option.</p></item>
          <tag><c>{file,FileName}</c></tag>
          <item><p>Installs <c>sasl_report_file_h</c> in the error logger.
            All reports go to file <c>FileName</c>, which is a
            string. The file is opened in <c>write</c> mode with encoding
	    <c>utf8</c>.</p></item>
          <tag><c>{file,FileName,Modes}</c></tag>
          <item><p>Same as <c>{file,FileName}</c>, except that <c>Modes</c>
            allows you to specify the modes used for opening the <c>FileName</c>
            given to the <seemfa marker="kernel:file#open/2">file:open/2</seemfa>
            call. By default, the file is opened in <c>write</c> mode
            with encoding <c>utf8</c>. Use <c>[append]</c> to have
            the <c>FileName</c> open in append mode. A different
            encoding can also be specified.
            <c>FileName</c> is a string.</p></item>
          <tag><c>false</c></tag>
          <item><p>No SASL error logger handler is installed.</p></item>
        </taglist>
      </item>
      <tag><c><![CDATA[errlog_type = error | progress | all ]]></c></tag>
      <item>
        <p>Restricts the error logging performed by the specified
          <c>sasl_error_logger</c> to error reports or progress reports,
          or both. Default is <c>all</c>.</p>
      </item>
      <tag><marker id="utc_log"/><c><![CDATA[utc_log = true | false ]]></c></tag>
      <item>
        <p>If set to <c>true</c>, all dates in textual log outputs are
          displayed in Universal Coordinated Time with the string
          <c>UTC</c> appended.</p>
      </item>
    </taglist>

    <p>The error logger event handler <c>log_mf_h</c> can also still
      be used. This event handler writes <em>all</em> events sent to
      the error logger to disk. Multiple files and log rotation are
      used. For efficiency reasons, each event is written as a
      binary. For more information about this handler,
      see <seeerl marker="stdlib:log_mf_h">the STDLIB Reference
      Manual</seeerl>.</p>
    <p>To activate this event handler, three SASL configuration
      parameters must be
      set:</p>
    <taglist>
      <tag><c><![CDATA[error_logger_mf_dir = string() | false ]]></c></tag>
      <item>
        <p>Specifies in which directory <c>log_mf_h</c> is to store
          its files. If this parameter is undefined or <c>false</c>,
          the <c>log_mf_h</c> handler is not installed.</p>
      </item>
      <tag><c><![CDATA[error_logger_mf_maxbytes = integer() ]]></c></tag>
      <item>
        <p>Specifies the maximum size of each individual file written
          by <c>log_mf_h</c>. If this parameter is undefined,
          the <c>log_mf_h</c> handler is not installed.</p>
      </item>
      <tag><c><![CDATA[error_logger_mf_maxfiles = 0<integer()<256 ]]></c></tag>
      <item>
        <p>Specifies the number of files used by <c>log_mf_h</c>. If
          this parameter is undefined, the <c>log_mf_h</c> handler is
          not installed.</p>
      </item>
    </taglist>
    <p>The new <seeerl marker="kernel:logger_disk_log_h">
	<c>logger_disk_log_h</c></seeerl> might be an alternative
      to <c>log_mf_h</c> if log rotation is desired. This does,
      however, write the log events in clear text and not as binaries.</p>

  </section>

  <section>
    <title>See Also</title>
    <p><seeerl marker="alarm_handler"><c>alarm_handler(3)</c></seeerl>,
      <seeerl marker="kernel:error_logger"><c>error_logger(3)</c></seeerl>,
      <seeerl marker="kernel:logger"><c>logger(3)</c></seeerl>,
      <seeerl marker="stdlib:log_mf_h"><c>log_mf_h(3)</c></seeerl>,
      <seeerl marker="rb"><c>rb(3)</c></seeerl>,
      <seeerl marker="release_handler"><c>release_handler(3)</c></seeerl>,
      <seeerl marker="systools"><c>systools(3)</c></seeerl></p>
  </section>
</appref>

