units: use symbolic exit code names

[thirdparty/systemd.git] / man / systemd-analyze.xml

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1+ -->

<refentry id="systemd-analyze"
    xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>systemd-analyze</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd-analyze</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd-analyze</refname>
    <refpurpose>Analyze and debug system manager</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg>time</arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">blame</arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">critical-chain</arg>
      <arg choice="opt" rep="repeat"><replaceable>UNIT</replaceable></arg>
    </cmdsynopsis>

    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">log-level</arg>
      <arg choice="opt"><replaceable>LEVEL</replaceable></arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">log-target</arg>
      <arg choice="opt"><replaceable>TARGET</replaceable></arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">service-watchdogs</arg>
      <arg choice="opt"><replaceable>BOOL</replaceable></arg>
    </cmdsynopsis>

    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">dump</arg>
    </cmdsynopsis>

    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">plot</arg>
      <arg choice="opt">>file.svg</arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">dot</arg>
      <arg choice="opt" rep="repeat"><replaceable>PATTERN</replaceable></arg>
      <arg choice="opt">>file.dot</arg>
    </cmdsynopsis>

    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">unit-paths</arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">condition</arg>
      <arg choice="plain"><replaceable>CONDITION</replaceable>…</arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">syscall-filter</arg>
      <arg choice="opt"><replaceable>SET</replaceable>…</arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">calendar</arg>
      <arg choice="plain" rep="repeat"><replaceable>SPEC</replaceable></arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">timestamp</arg>
      <arg choice="plain" rep="repeat"><replaceable>TIMESTAMP</replaceable></arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">timespan</arg>
      <arg choice="plain" rep="repeat"><replaceable>SPAN</replaceable></arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">cat-config</arg>
      <arg choice="plain" rep="repeat"><replaceable>NAME</replaceable>|<replaceable>PATH</replaceable></arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">verify</arg>
      <arg choice="opt" rep="repeat"><replaceable>FILE</replaceable></arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-analyze</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain">security</arg>
      <arg choice="plain" rep="repeat"><replaceable>UNIT</replaceable></arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><command>systemd-analyze</command> may be used to determine
    system boot-up performance statistics and retrieve other state and
    tracing information from the system and service manager, and to
    verify the correctness of unit files. It is also used to access
    special functions useful for advanced system manager debugging.</para>

    <para>If no command is passed, <command>systemd-analyze
    time</command> is implied.</para>

    <refsect2>
      <title><command>systemd-analyze time</command></title>

      <para>This command prints the time spent in the kernel before userspace has been reached, the time
      spent in the initial RAM disk (initrd) before normal system userspace has been reached, and the time
      normal system userspace took to initialize. Note that these measurements simply measure the time passed
      up to the point where all system services have been spawned, but not necessarily until they fully
      finished initialization or the disk is idle.</para>

      <example>
        <title><command>Show how long the boot took</command></title>

        <programlisting># in a container
$ systemd-analyze time
Startup finished in 296ms (userspace)
multi-user.target reached after 275ms in userspace

# on a real machine
$ systemd-analyze time
Startup finished in 2.584s (kernel) + 19.176s (initrd) + 47.847s (userspace) = 1min 9.608s
multi-user.target reached after 47.820s in userspace
</programlisting>
      </example>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze blame</command></title>

      <para>This command prints a list of all running units, ordered by the time they took to initialize.
      This information may be used to optimize boot-up times. Note that the output might be misleading as the
      initialization of one service might be slow simply because it waits for the initialization of another
      service to complete.  Also note: <command>systemd-analyze blame</command> doesn't display results for
      services with <varname>Type=simple</varname>, because systemd considers such services to be started
      immediately, hence no measurement of the initialization delays can be done. Also note that this command
      only shows the time units took for starting up, it does not show how long unit jobs spent in the
      execution queue. In particular it shows the time units spent in <literal>activating</literal> state,
      which is not defined for units such as device units that transition directly from
      <literal>inactive</literal> to <literal>active</literal>. This command hence gives an impression of the
      performance of program code, but cannot accurately reflect latency introduced by waiting for
      hardware and similar events.</para>

      <example>
        <title><command>Show which units took the most time during boot</command></title>

        <programlisting>$ systemd-analyze blame
         32.875s pmlogger.service
         20.905s systemd-networkd-wait-online.service
         13.299s dev-vda1.device
         ...
            23ms sysroot.mount
            11ms initrd-udevadm-cleanup-db.service
             3ms sys-kernel-config.mount
        </programlisting>
      </example>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze critical-chain <optional><replaceable>UNIT</replaceable>...</optional></command></title>

      <para>This command prints a tree of the time-critical chain of units (for each of the specified
      <replaceable>UNIT</replaceable>s or for the default target otherwise). The time after the unit is
      active or started is printed after the "@" character. The time the unit takes to start is printed after
      the "+" character. Note that the output might be misleading as the initialization of services might
      depend on socket activation and because of the parallel execution of units. Also, similar to the
      <command>blame</command> command, this only takes into account the time units spent in
      <literal>activating</literal> state, and hence does not cover units that never went through an
      <literal>activating</literal> state (such as device units that transition directly from
      <literal>inactive</literal> to <literal>active</literal>). Moreover it does not show information on
      jobs (and in particular not jobs that timed out).</para>

      <example>
        <title><command>systemd-analyze time</command></title>

      <programlisting>$ systemd-analyze critical-chain
multi-user.target @47.820s
└─pmie.service @35.968s +548ms
  └─pmcd.service @33.715s +2.247s
    └─network-online.target @33.712s
      └─systemd-networkd-wait-online.service @12.804s +20.905s
        └─systemd-networkd.service @11.109s +1.690s
          └─systemd-udevd.service @9.201s +1.904s
            └─systemd-tmpfiles-setup-dev.service @7.306s +1.776s
              └─kmod-static-nodes.service @6.976s +177ms
                └─systemd-journald.socket
                  └─system.slice
                    └─-.slice
</programlisting>
      </example>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze log-level [<replaceable>LEVEL</replaceable>]</command></title>

      <para><command>systemd-analyze log-level</command> prints the current log level of the
      <command>systemd</command> daemon.  If an optional argument <replaceable>LEVEL</replaceable> is
      provided, then the command changes the current log level of the <command>systemd</command> daemon to
      <replaceable>LEVEL</replaceable> (accepts the same values as <option>--log-level=</option> described in
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>).</para>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze log-target [<replaceable>TARGET</replaceable>]</command></title>

      <para><command>systemd-analyze log-target</command> prints the current log target of the
      <command>systemd</command> daemon.  If an optional argument <replaceable>TARGET</replaceable> is
      provided, then the command changes the current log target of the <command>systemd</command> daemon to
      <replaceable>TARGET</replaceable> (accepts the same values as <option>--log-target=</option>, described
      in <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>).</para>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze service-watchdogs [yes|no]</command></title>

      <para><command>systemd-analyze service-watchdogs</command> prints the current state of service runtime
      watchdogs of the <command>systemd</command> daemon. If an optional boolean argument is provided, then
      globally enables or disables the service runtime watchdogs (<option>WatchdogSec=</option>) and
      emergency actions (e.g.  <option>OnFailure=</option> or <option>StartLimitAction=</option>); see
      <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
      The hardware watchdog is not affected by this setting.</para>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze dump</command></title>

      <para>This command outputs a (usually very long) human-readable serialization of the complete server
      state. Its format is subject to change without notice and should not be parsed by applications.</para>

      <example>
        <title>Show the internal state of user manager</title>

        <programlisting>$ systemd-analyze --user dump
Timestamp userspace: Thu 2019-03-14 23:28:07 CET
Timestamp finish: Thu 2019-03-14 23:28:07 CET
Timestamp generators-start: Thu 2019-03-14 23:28:07 CET
Timestamp generators-finish: Thu 2019-03-14 23:28:07 CET
Timestamp units-load-start: Thu 2019-03-14 23:28:07 CET
Timestamp units-load-finish: Thu 2019-03-14 23:28:07 CET
-> Unit proc-timer_list.mount:
        Description: /proc/timer_list
        ...
-> Unit default.target:
        Description: Main user target
...
</programlisting>
      </example>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze plot</command></title>

      <para>This command prints an SVG graphic detailing which system services have been started at what
      time, highlighting the time they spent on initialization.</para>

      <example>
        <title><command>Plot a bootchart</command></title>

        <programlisting>$ systemd-analyze plot >bootup.svg
$ eog bootup.svg&amp;
</programlisting>
      </example>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze dot [<replaceable>pattern</replaceable>...]</command></title>

      <para>This command generates textual dependency graph description in dot format for further processing
      with the GraphViz
      <citerefentry project='die-net'><refentrytitle>dot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
      tool. Use a command line like <command>systemd-analyze dot | dot -Tsvg >systemd.svg</command> to
      generate a graphical dependency tree. Unless <option>--order</option> or <option>--require</option> is
      passed, the generated graph will show both ordering and requirement dependencies. Optional pattern
      globbing style specifications (e.g. <filename>*.target</filename>) may be given at the end. A unit
      dependency is included in the graph if any of these patterns match either the origin or destination
      node.</para>

      <example>
        <title>Plot all dependencies of any unit whose name starts with <literal>avahi-daemon</literal>
        </title>

        <programlisting>$ systemd-analyze dot 'avahi-daemon.*' | dot -Tsvg >avahi.svg
$ eog avahi.svg</programlisting>
      </example>

      <example>
        <title>Plot the dependencies between all known target units</title>

        <programlisting>$ systemd-analyze dot --to-pattern='*.target' --from-pattern='*.target' \
      | dot -Tsvg >targets.svg
$ eog targets.svg</programlisting>
      </example>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze unit-paths</command></title>

      <para>This command outputs a list of all directories from which unit files, <filename>.d</filename>
      overrides, and <filename>.wants</filename>, <filename>.requires</filename> symlinks may be
      loaded. Combine with <option>--user</option> to retrieve the list for the user manager instance, and
      <option>--global</option> for the global configuration of user manager instances.</para>

      <example>
        <title><command>Show all paths for generated units</command></title>

        <programlisting>$ systemd-analyze unit-paths | grep '^/run'
/run/systemd/system.control
/run/systemd/transient
/run/systemd/generator.early
/run/systemd/system
/run/systemd/system.attached
/run/systemd/generator
/run/systemd/generator.late
</programlisting>
      </example>

      <para>Note that this verb prints the list that is compiled into <command>systemd-analyze</command>
      itself, and does not communicate with the running manager. Use
      <programlisting>systemctl [--user] [--global] show -p UnitPath --value</programlisting>
      to retrieve the actual list that the manager uses, with any empty directories omitted.</para>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze condition <replaceable>CONDITION</replaceable>...</command></title>

      <para>This command will evaluate <varname noindex='true'>Condition*=...</varname> and
      <varname noindex='true'>Assert*=...</varname> assignments, and print their values, and
      the resulting value of the combined condition set. See
      <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
      for a list of available conditions and asserts.</para>

      <example>
        <title>Evaluate conditions that check kernel versions</title>

        <programlisting>$ systemd-analyze condition 'ConditionKernelVersion = ! &lt;4.0' \
        'ConditionKernelVersion = &gt;=5.1' \
        'ConditionACPower=|false' \
        'ConditionArchitecture=|!arm' \
        'AssertPathExists=/etc/os-release'
test.service: AssertPathExists=/etc/os-release succeeded.
Asserts succeeded.
test.service: ConditionArchitecture=|!arm succeeded.
test.service: ConditionACPower=|false failed.
test.service: ConditionKernelVersion=&gt;=5.1 succeeded.
test.service: ConditionKernelVersion=!&lt;4.0 succeeded.
Conditions succeeded.</programlisting>
      </example>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze syscall-filter <optional><replaceable>SET</replaceable>...</optional></command></title>

      <para>This command will list system calls contained in the specified system call set
      <replaceable>SET</replaceable>, or all known sets if no sets are specified. Argument
      <replaceable>SET</replaceable> must include the <literal>@</literal> prefix.</para>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze calendar <replaceable>EXPRESSION</replaceable>...</command></title>

      <para>This command will parse and normalize repetitive calendar time events, and will calculate when
      they elapse next. This takes the same input as the <varname>OnCalendar=</varname> setting in
      <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      following the syntax described in
      <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>. By
      default, only the next time the calendar expression will elapse is shown; use
      <option>--iterations=</option> to show the specified number of next times the expression
      elapses. Each time the expression elapses forms a timestamp, see the <command>timestamp</command>
      verb below.</para>

      <example>
        <title>Show leap days in the near future</title>

        <programlisting>$ systemd-analyze calendar --iterations=5 '*-2-29 0:0:0'
  Original form: *-2-29 0:0:0
Normalized form: *-02-29 00:00:00
    Next elapse: Sat 2020-02-29 00:00:00 UTC
       From now: 11 months 15 days left
       Iter. #2: Thu 2024-02-29 00:00:00 UTC
       From now: 4 years 11 months left
       Iter. #3: Tue 2028-02-29 00:00:00 UTC
       From now: 8 years 11 months left
       Iter. #4: Sun 2032-02-29 00:00:00 UTC
       From now: 12 years 11 months left
       Iter. #5: Fri 2036-02-29 00:00:00 UTC
       From now: 16 years 11 months left
</programlisting>
      </example>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze timestamp <replaceable>TIMESTAMP</replaceable>...</command></title>

      <para>This command parses a timestamp (i.e. a single point in time) and outputs the normalized form and
      the difference between this timestamp and now. The timestamp should adhere to the syntax documented in
      <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
      section "PARSING TIMESTAMPS".</para>

      <example>
        <title>Show parsing of timestamps</title>

        <programlisting>$ systemd-analyze timestamp yesterday now tomorrow
  Original form: yesterday
Normalized form: Mon 2019-05-20 00:00:00 CEST
       (in UTC): Sun 2019-05-19 22:00:00 UTC
   UNIX seconds: @15583032000
       From now: 1 day 9h ago

  Original form: now
Normalized form: Tue 2019-05-21 09:48:39 CEST
       (in UTC): Tue 2019-05-21 07:48:39 UTC
   UNIX seconds: @1558424919.659757
       From now: 43us ago

  Original form: tomorrow
Normalized form: Wed 2019-05-22 00:00:00 CEST
       (in UTC): Tue 2019-05-21 22:00:00 UTC
   UNIX seconds: @15584760000
       From now: 14h left
</programlisting>
      </example>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze timespan <replaceable>EXPRESSION</replaceable>...</command></title>

      <para>This command parses a time span (i.e. a difference between two timestamps) and outputs the
      normalized form and the equivalent value in microseconds. The time span should adhere to the syntax
      documented in
      <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
      section "PARSING TIME SPANS". Values without units are parsed as seconds.</para>

      <example>
        <title>Show parsing of timespans</title>

        <programlisting>$ systemd-analyze timespan 1s 300s '1year 0.000001s'
Original: 1s
      μs: 1000000
   Human: 1s

Original: 300s
      μs: 300000000
   Human: 5min

Original: 1year 0.000001s
      μs: 31557600000001
   Human: 1y 1us
</programlisting>
      </example>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze cat-config</command>
      <replaceable>NAME</replaceable>|<replaceable>PATH</replaceable>...</title>

      <para>This command is similar to <command>systemctl cat</command>, but operates on config files. It
      will copy the contents of a config file and any drop-ins to standard output, using the usual systemd
      set of directories and rules for precedence. Each argument must be either an absolute path including
      the prefix (such as <filename>/etc/systemd/logind.conf</filename> or
      <filename>/usr/lib/systemd/logind.conf</filename>), or a name relative to the prefix (such as
      <filename>systemd/logind.conf</filename>).</para>

      <example>
        <title>Showing logind configuration</title>
        <programlisting>$ systemd-analyze cat-config systemd/logind.conf
# /etc/systemd/logind.conf
...
[Login]
NAutoVTs=8
...

# /usr/lib/systemd/logind.conf.d/20-test.conf
... some override from another package

# /etc/systemd/logind.conf.d/50-override.conf
... some administrator override
        </programlisting>
      </example>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze verify <replaceable>FILE</replaceable>...</command></title>

      <para>This command will load unit files and print warnings if any errors are detected. Files specified
      on the command line will be loaded, but also any other units referenced by them. The full unit search
      path is formed by combining the directories for all command line arguments, and the usual unit load
      paths (variable <varname>$SYSTEMD_UNIT_PATH</varname> is supported, and may be used to replace or
      augment the compiled in set of unit load paths; see
      <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>).  All
      units files present in the directories containing the command line arguments will be used in preference
      to the other paths.</para>

      <para>The following errors are currently detected:</para>
      <itemizedlist>
        <listitem><para>unknown sections and directives,</para></listitem>

        <listitem><para>missing dependencies which are required to start the given unit,</para></listitem>

        <listitem><para>man pages listed in <varname>Documentation=</varname> which are not found in the
        system,</para></listitem>

        <listitem><para>commands listed in <varname>ExecStart=</varname> and similar which are not found in
        the system or not executable.</para></listitem>
      </itemizedlist>

      <example>
        <title>Misspelt directives</title>

        <programlisting>$ cat ./user.slice
[Unit]
WhatIsThis=11
Documentation=man:nosuchfile(1)
Requires=different.service

[Service]
Description=x

$ systemd-analyze verify ./user.slice
[./user.slice:9] Unknown lvalue 'WhatIsThis' in section 'Unit'
[./user.slice:13] Unknown section 'Service'. Ignoring.
Error: org.freedesktop.systemd1.LoadFailed:
   Unit different.service failed to load:
   No such file or directory.
Failed to create user.slice/start: Invalid argument
user.slice: man nosuchfile(1) command failed with code 16
        </programlisting>
      </example>

      <example>
        <title>Missing service units</title>

        <programlisting>$ tail ./a.socket ./b.socket
==> ./a.socket &lt;==
[Socket]
ListenStream=100

==> ./b.socket &lt;==
[Socket]
ListenStream=100
Accept=yes

$ systemd-analyze verify ./a.socket ./b.socket
Service a.service not loaded, a.socket cannot be started.
Service b@0.service not loaded, b.socket cannot be started.
        </programlisting>
      </example>
    </refsect2>

    <refsect2>
      <title><command>systemd-analyze security <optional><replaceable>UNIT</replaceable>...</optional></command></title>

      <para>This command analyzes the security and sandboxing settings of one or more specified service
      units. If at least one unit name is specified the security settings of the specified service units are
      inspected and a detailed analysis is shown. If no unit name is specified, all currently loaded,
      long-running service units are inspected and a terse table with results shown. The command checks for
      various security-related service settings, assigning each a numeric "exposure level" value, depending
      on how important a setting is. It then calculates an overall exposure level for the whole unit, which
      is an estimation in the range 0.0…10.0 indicating how exposed a service is security-wise. High exposure
      levels indicate very little applied sandboxing. Low exposure levels indicate tight sandboxing and
      strongest security restrictions. Note that this only analyzes the per-service security features systemd
      itself implements. This means that any additional security mechanisms applied by the service code
      itself are not accounted for. The exposure level determined this way should not be misunderstood: a
      high exposure level neither means that there is no effective sandboxing applied by the service code
      itself, nor that the service is actually vulnerable to remote or local attacks. High exposure levels do
      indicate however that most likely the service might benefit from additional settings applied to
      them.</para>

      <para>Please note that many of the security and sandboxing settings individually can be circumvented —
      unless combined with others. For example, if a service retains the privilege to establish or undo mount
      points many of the sandboxing options can be undone by the service code itself. Due to that is
      essential that each service uses the most comprehensive and strict sandboxing and security settings
      possible. The tool will take into account some of these combinations and relationships between the
      settings, but not all. Also note that the security and sandboxing settings analyzed here only apply to
      the operations executed by the service code itself. If a service has access to an IPC system (such as
      D-Bus) it might request operations from other services that are not subject to the same
      restrictions. Any comprehensive security and sandboxing analysis is hence incomplete if the IPC access
      policy is not validated too.</para>

      <example>
      <title>Analyze <filename noindex="true">systemd-logind.service</filename></title>

      <programlisting>$ systemd-analyze security --no-pager systemd-logind.service
  NAME                DESCRIPTION                              EXPOSURE
✗ PrivateNetwork=     Service has access to the host's network      0.5
✗ User=/DynamicUser=  Service runs as root user                     0.4
✗ DeviceAllow=        Service has no device ACL                     0.2
✓ IPAddressDeny=      Service blocks all IP address ranges
...
→ Overall exposure level for systemd-logind.service: 4.1 OK 🙂
</programlisting>
      </example>
    </refsect2>
  </refsect1>

  <refsect1>
    <title>Options</title>

    <para>The following options are understood:</para>

    <variablelist>
      <varlistentry>
        <term><option>--system</option></term>

        <listitem><para>Operates on the system systemd instance. This
        is the implied default.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--user</option></term>

        <listitem><para>Operates on the user systemd
        instance.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--global</option></term>

        <listitem><para>Operates on the system-wide configuration for
        user systemd instance.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--order</option></term>
        <term><option>--require</option></term>

        <listitem><para>When used in conjunction with the
        <command>dot</command> command (see above), selects which
        dependencies are shown in the dependency graph. If
        <option>--order</option> is passed, only dependencies of type
        <varname>After=</varname> or <varname>Before=</varname> are
        shown. If <option>--require</option> is passed, only
        dependencies of type <varname>Requires=</varname>,
        <varname>Requisite=</varname>,
        <varname>Wants=</varname> and <varname>Conflicts=</varname>
        are shown. If neither is passed, this shows dependencies of
        all these types.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--from-pattern=</option></term>
        <term><option>--to-pattern=</option></term>

        <listitem><para>When used in conjunction with the
        <command>dot</command> command (see above), this selects which
        relationships are shown in the dependency graph. Both options
        require a
        <citerefentry project='die-net'><refentrytitle>glob</refentrytitle><manvolnum>7</manvolnum></citerefentry>
        pattern as an argument, which will be matched against the
        left-hand and the right-hand, respectively, nodes of a
        relationship.</para>

        <para>Each of these can be used more than once, in which case
        the unit name must match one of the values. When tests for
        both sides of the relation are present, a relation must pass
        both tests to be shown. When patterns are also specified as
        positional arguments, they must match at least one side of the
        relation. In other words, patterns specified with those two
        options will trim the list of edges matched by the positional
        arguments, if any are given, and fully determine the list of
        edges shown otherwise.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--fuzz=</option><replaceable>timespan</replaceable></term>

        <listitem><para>When used in conjunction with the
        <command>critical-chain</command> command (see above), also
        show units, which finished <replaceable>timespan</replaceable>
        earlier, than the latest unit in the same level. The unit of
        <replaceable>timespan</replaceable> is seconds unless
        specified with a different unit, e.g.
        "50ms".</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--man=no</option></term>

        <listitem><para>Do not invoke man to verify the existence of
        man pages listed in <varname>Documentation=</varname>.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--generators</option></term>

        <listitem><para>Invoke unit generators, see
        <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
        Some generators require root privileges. Under a normal user, running with
        generators enabled will generally result in some warnings.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--root=<replaceable>PATH</replaceable></option></term>

        <listitem><para>With <command>cat-files</command>, show config files underneath
        the specified root path <replaceable>PATH</replaceable>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--iterations=<replaceable>NUMBER</replaceable></option></term>

        <listitem><para>When used with the <command>calendar</command> command, show the specified number of
        iterations the specified calendar expression will elapse next. Defaults to 1.</para></listitem>
      </varlistentry>

      <xi:include href="user-system-options.xml" xpointer="host" />
      <xi:include href="user-system-options.xml" xpointer="machine" />

      <xi:include href="standard-options.xml" xpointer="help" />
      <xi:include href="standard-options.xml" xpointer="version" />
      <xi:include href="standard-options.xml" xpointer="no-pager" />
    </variablelist>

  </refsect1>

  <refsect1>
    <title>Exit status</title>

    <para>On success, 0 is returned, a non-zero failure code
    otherwise.</para>
  </refsect1>

  <xi:include href="less-variables.xml" />

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>