coredumpctl: Add support for the --root option

[thirdparty/systemd.git] / man / coredumpctl.xml

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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<refentry id="coredumpctl" conditional='ENABLE_COREDUMP'
    xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>coredumpctl</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>coredumpctl</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>coredumpctl</refname>
    <refpurpose>Retrieve and process saved core dumps and metadata</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>coredumpctl</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="req">COMMAND</arg>
      <arg choice="opt" rep="repeat">PID|COMM|EXE|MATCH</arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><command>coredumpctl</command> is a tool that can be used to retrieve and process core
    dumps and metadata which were saved by
    <citerefentry><refentrytitle>systemd-coredump</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
    </para>
  </refsect1>

  <refsect1>
    <title>Commands</title>

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

    <variablelist>
      <varlistentry>
        <term><command>list</command></term>

        <listitem><para>List core dumps captured in the journal
        matching specified characteristics. If no command is
        specified, this is the implied default.</para>

        <para>The output is designed to be human readable and contains a table with the following
        columns:</para>
        <variablelist>
          <varlistentry>
            <term>TIME</term>
            <listitem><para>The timestamp of the crash, as reported by the kernel.</para>
            </listitem>
          </varlistentry>

          <varlistentry>
            <term>PID</term>
            <listitem><para>The identifier of the process that crashed.</para>
            </listitem>
          </varlistentry>

          <varlistentry>
            <term>UID</term>
            <term>GID</term>
            <listitem><para>The user and group identifiers of the process that crashed.</para>
            </listitem>
          </varlistentry>

          <varlistentry>
            <term>SIGNAL</term>
            <listitem><para>The signal that caused the process to crash, when applicable.
            </para></listitem>
          </varlistentry>

          <varlistentry>
            <term>COREFILE</term>
            <listitem><para>Information whether the coredump was stored, and whether
            it is still accessible: <literal>none</literal> means the core was
            not stored, <literal>-</literal> means that it was not available (for
            example because the process was not terminated by a signal),
            <literal>present</literal> means that the core file is accessible by the
            current user, <literal>journal</literal> means that the core was stored
            in the <literal>journal</literal>, <literal>truncated</literal> is the
            same as one of the previous two, but the core was too large and was not
            stored in its entirety, <literal>error</literal> means that the core file
            cannot be accessed, most likely because of insufficient permissions, and
            <literal>missing</literal> means that the core was stored in a file, but
            this file has since been removed.</para></listitem>
          </varlistentry>

          <varlistentry>
            <term>EXE</term>
            <listitem><para>The full path to the executable. For backtraces of scripts
            this is the name of the interpreter.</para></listitem>
          </varlistentry>
        </variablelist>

        <para>It's worth noting that different restrictions apply to
        data saved in the journal and core dump files saved in
        <filename>/var/lib/systemd/coredump</filename>, see overview in
        <citerefentry><refentrytitle>systemd-coredump</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
        Thus it may very well happen that a particular core dump is still listed
        in the journal while its corresponding core dump file has already been
        removed.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>info</command></term>

        <listitem><para>Show detailed information about the last core dump
        or core dumps matching specified characteristics
        captured in the journal.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>dump</command></term>

        <listitem><para>Extract the last core dump matching specified
        characteristics. The core dump will be written on standard
        output, unless an output file is specified with
        <option>--output=</option>. </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>debug</command></term>

        <listitem><para>Invoke a debugger on the last core dump
        matching specified characteristics. By default,
        <citerefentry project='man-pages'><refentrytitle>gdb</refentrytitle><manvolnum>1</manvolnum></citerefentry>
        will be used. This may be changed using the <option>--debugger=</option>
        option or the <varname>$SYSTEMD_DEBUGGER</varname> environment
        variable. Use the <option>--debugger-arguments=</option> option to pass extra
        command line arguments to the debugger.</para></listitem>
      </varlistentry>

    </variablelist>

  </refsect1>

  <refsect1>
    <title>Options</title>

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

    <variablelist>

      <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" />
      <xi:include href="standard-options.xml" xpointer="no-legend" />
      <xi:include href="standard-options.xml" xpointer="json" />

      <varlistentry>
        <term><option>-1</option></term>

        <listitem><para>Show information of the most recent core dump only, instead of listing all known core
        dumps. Equivalent to <option>--reverse -n 1</option>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-n</option> <replaceable>INT</replaceable></term>

        <listitem><para>Show at most the specified number of entries. The specified parameter must be an
        integer greater or equal to 1.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-S</option></term>
        <term><option>--since</option></term>

        <listitem><para>Only print entries which are since the specified date.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-U</option></term>
        <term><option>--until</option></term>

        <listitem><para>Only print entries which are until the specified date.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-r</option></term>
        <term><option>--reverse</option></term>

        <listitem><para>Reverse output so that the newest entries are displayed first.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-F</option> <replaceable>FIELD</replaceable></term>
        <term><option>--field=</option><replaceable>FIELD</replaceable></term>

        <listitem><para>Print all possible data values the specified
        field takes in matching core dump entries of the
        journal.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-o</option> <replaceable>FILE</replaceable></term>
        <term><option>--output=</option><replaceable>FILE</replaceable></term>

        <listitem><para>Write the core to <option>FILE</option>.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--debugger=</option><replaceable>DEBUGGER</replaceable></term>

        <listitem><para>Use the given debugger for the <command>debug</command>
        command. If not given and <varname>$SYSTEMD_DEBUGGER</varname> is unset, then
        <citerefentry project='man-pages'><refentrytitle>gdb</refentrytitle><manvolnum>1</manvolnum></citerefentry>
        will be used. </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-A</option> <replaceable>ARGS</replaceable></term>
        <term><option>--debugger-arguments=</option><replaceable>ARGS</replaceable></term>

        <listitem><para>Pass the given <replaceable>ARGS</replaceable> as extra command line arguments
        to the debugger. Quote as appropriate when <replaceable>ARGS</replaceable> contain whitespace.
        (See Examples.)</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--file=<replaceable>GLOB</replaceable></option></term>

        <listitem><para>Takes a file glob as an argument. If
        specified, coredumpctl will operate on the specified journal
        files matching <replaceable>GLOB</replaceable> instead of the
        default runtime and system journal paths. May be specified
        multiple times, in which case files will be suitably
        interleaved.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-D</option> <replaceable>DIR</replaceable></term>
        <term><option>--directory=</option><replaceable>DIR</replaceable></term>

        <listitem><para>Use the journal files in the specified <option>DIR</option>.
        </para></listitem>
      </varlistentry>

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

        <listitem><para>Use root directory <option>ROOT</option> when searching for coredumps.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-q</option></term>
        <term><option>--quiet</option></term>

        <listitem><para>Suppresses informational messages about lack
        of access to journal files and possible in-flight coredumps.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--all</option></term>

        <listitem><para>Look at all available journal files in <filename>/var/log/journal/</filename>
        (excluding journal namespaces) instead of only local ones.</para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Matching</title>

    <para>A match can be:</para>

    <variablelist>
      <varlistentry>
        <term><replaceable>PID</replaceable></term>

        <listitem><para>Process ID of the
        process that dumped
        core. An integer.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><replaceable>COMM</replaceable></term>

        <listitem><para>Name of the executable (matches
        <option>COREDUMP_COMM=</option>). Must not contain slashes.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><replaceable>EXE</replaceable></term>

        <listitem><para>Path to the executable (matches
        <option>COREDUMP_EXE=</option>). Must contain at least one
        slash. </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><replaceable>MATCH</replaceable></term>

        <listitem><para>General journalctl match filter, must contain an equals
        sign (<literal>=</literal>). See
        <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
        </para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Exit status</title>
    <para>On success, 0 is returned; otherwise, a non-zero failure
    code is returned. Not finding any matching core dumps is treated as
    failure.
    </para>
  </refsect1>

  <refsect1>
    <title>Environment</title>

    <variablelist class='environment-variables'>
      <varlistentry>
        <term><varname>$SYSTEMD_DEBUGGER</varname></term>
        <listitem><para>Use the given debugger for the <command>debug</command>
        command. See the <option>--debugger=</option> option.</para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Examples</title>

    <example>
      <title>List all the core dumps of a program</title>

      <programlisting>$ coredumpctl list /usr/lib64/firefox/firefox
TIME       PID  UID  GID SIG     COREFILE EXE                         SIZE
Tue …   8018 1000 1000 SIGSEGV missing  /usr/lib64/firefox/firefox     -
Wed … 251609 1000 1000 SIGTRAP missing  /usr/lib64/firefox/firefox     -
Fri … 552351 1000 1000 SIGSEGV present  /usr/lib64/firefox/firefox 28.7M
</programlisting>

       <para>The journal has three entries pertaining to <filename>/usr/lib64/firefox/firefox</filename>, and
       only the last entry still has an available core file (in external storage on disk).</para>

       <para>Note that <filename>coredumpctl</filename> needs access to the journal files to retrieve the
       relevant entries from the journal. Thus, an unprivileged user will normally only see information about
       crashing programs of this user.</para>
    </example>

    <example>
      <title>Invoke <command>gdb</command> on the last core dump</title>

      <programlisting>$ coredumpctl debug</programlisting>
    </example>

    <example>
      <title>Use <command>gdb</command> to display full register info from the last core dump</title>

      <programlisting>$ coredumpctl debug --debugger-arguments="-batch -ex 'info all-registers'"</programlisting>
    </example>

    <example>
      <title>Show information about a core dump matched by PID</title>

      <programlisting>$ coredumpctl info 6654
           PID: 6654 (bash)
           UID: 1000 (user)
           GID: 1000 (user)
        Signal: 11 (SEGV)
     Timestamp: Mon 2021-01-01 00:00:01 CET (20s ago)
  Command Line: bash -c $'kill -SEGV $$'
    Executable: /usr/bin/bash
 Control Group: /user.slice/user-1000.slice/…
          Unit: user@1000.service
     User Unit: vte-spawn-….scope
         Slice: user-1000.slice
     Owner UID: 1000 (user)
       Boot ID: …
    Machine ID: …
      Hostname: …
       Storage: /var/lib/systemd/coredump/core.bash.1000.….zst (present)
  Size on Disk: 51.7K
       Message: Process 130414 (bash) of user 1000 dumped core.

                Stack trace of thread 130414:
                #0  0x00007f398142358b kill (libc.so.6 + 0x3d58b)
                #1  0x0000558c2c7fda09 kill_builtin (bash + 0xb1a09)
                #2  0x0000558c2c79dc59 execute_builtin.lto_priv.0 (bash + 0x51c59)
                #3  0x0000558c2c79709c execute_simple_command (bash + 0x4b09c)
                #4  0x0000558c2c798408 execute_command_internal (bash + 0x4c408)
                #5  0x0000558c2c7f6bdc parse_and_execute (bash + 0xaabdc)
                #6  0x0000558c2c85415c run_one_command.isra.0 (bash + 0x10815c)
                #7  0x0000558c2c77d040 main (bash + 0x31040)
                #8  0x00007f398140db75 __libc_start_main (libc.so.6 + 0x27b75)
                #9  0x0000558c2c77dd1e _start (bash + 0x31d1e)
</programlisting>
    </example>

    <example>
      <title>Extract the last core dump of /usr/bin/bar to a file named
      <filename index="false">bar.coredump</filename></title>

      <programlisting>$ coredumpctl -o bar.coredump dump /usr/bin/bar</programlisting>
    </example>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd-coredump</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>coredump.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry project='man-pages'><refentrytitle>gdb</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>