<refnamediv>
<refname>coredump.conf</refname>
<refname>coredump.conf.d</refname>
- <refpurpose>Coredump storage configuration files</refpurpose>
+ <refpurpose>Core dump storage configuration files</refpurpose>
</refnamediv>
<refsynopsisdiv>
<listitem><para>Controls where to store cores. One of
<literal>none</literal>, <literal>external</literal>,
<literal>journal</literal>, and <literal>both</literal>. When
- <literal>none</literal>, the coredumps will be logged but not
+ <literal>none</literal>, the core dumps will be logged but not
stored permanently. When <literal>external</literal> (the
default), cores will be stored in <filename>/var/lib/systemd/coredump</filename>.
When <literal>journal</literal>, cores will be stored in
<term><varname>ProcessSizeMax=</varname></term>
<listitem><para>The maximum size in bytes of a core
- which will be processed. Coredumps exceeding this size
+ which will be processed. Core dumps exceeding this size
will be logged, but the backtrace will not be generated
and the core will not be stored.</para></listitem>
</varlistentry>
<term><varname>KeepFree=</varname></term>
<listitem><para>Enforce limits on the disk space taken up by
- externally stored coredumps. <option>MaxUse=</option> makes
- sure that old coredumps are removed as soon as the total disk
- space taken up by coredumps grows beyond this limit (defaults
+ externally stored core dumps. <option>MaxUse=</option> makes
+ sure that old core dumps are removed as soon as the total disk
+ space taken up by core dumps grows beyond this limit (defaults
to 10% of the total disk size). <option>KeepFree=</option>
controls how much disk space to keep free at least (defaults
to 15% of the total disk size). Note that the disk space used
- by coredumps might temporarily exceed these limits while
- coredumps are processed. Note that old coredumps are also
+ by core dumps might temporarily exceed these limits while
+ core dumps are processed. Note that old core dumps are also
removed based on time via
<citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>. Set
either value to 0 to turn off size-based
<refnamediv>
<refname>coredumpctl</refname>
- <refpurpose>Retrieve coredumps from the journal</refpurpose>
+ <refpurpose>Retrieve and process saved core dumps and metadata</refpurpose>
</refnamediv>
<refsynopsisdiv>
<refsect1>
<title>Description</title>
- <para><command>coredumpctl</command> may be used to
- retrieve coredumps from
- <citerefentry><refentrytitle>systemd-journald</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
+ <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>
<para>The following options are understood:</para>
<variablelist>
+
+ <xi:include href="standard-options.xml" xpointer="help" />
+ <xi:include href="standard-options.xml" xpointer="version" />
+
<varlistentry>
<term><option>--no-legend</option></term>
- <listitem><para>Do not print column headers.
- </para></listitem>
+ <listitem><para>Do not print column headers.</para></listitem>
</varlistentry>
+ <xi:include href="standard-options.xml" xpointer="no-pager" />
+
<varlistentry>
<term><option>-1</option></term>
- <listitem><para>Show information of a single coredump only,
- instead of listing all known coredumps. </para></listitem>
+ <listitem><para>Show information of a single core dump only, instead of listing
+ all known core dumps.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--field=</option><replaceable>FIELD</replaceable></term>
<listitem><para>Print all possible data values the specified
- field takes in matching coredump entries of the
+ field takes in matching core dump entries of the
journal.</para></listitem>
</varlistentry>
</para></listitem>
</varlistentry>
- <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>Commands</title>
<para>The following commands are understood:</para>
<varlistentry>
<term><command>list</command></term>
- <listitem><para>List coredumps captured in the journal
+ <listitem><para>List core dumps captured in the journal
matching specified characteristics. If no command is
- specified, this is the implied default.</para></listitem>
+ specified, this is the implied default.</para>
+
+ <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 coredumps
+ <listitem><para>Show detailed information about core dumps
captured in the journal.</para></listitem>
</varlistentry>
<varlistentry>
<term><command>dump</command></term>
- <listitem><para>Extract the last coredump matching specified
- characteristics. The coredump will be written on standard
+ <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>gdb</command></term>
- <listitem><para>Invoke the GNU debugger on the last coredump
+ <listitem><para>Invoke the GNU debugger on the last core dump
matching specified characteristics. </para></listitem>
</varlistentry>
<refsect1>
<title>Exit status</title>
<para>On success, 0 is returned; otherwise, a non-zero failure
- code is returned. Not finding any matching coredumps is treated as
+ code is returned. Not finding any matching core dumps is treated as
failure.
</para>
</refsect1>
<title>Examples</title>
<example>
- <title>List all the coredumps of a program named foo</title>
+ <title>List all the core dumps of a program named foo</title>
<programlisting># coredumpctl list foo</programlisting>
</example>
<example>
- <title>Invoke gdb on the last coredump</title>
+ <title>Invoke gdb on the last core dump</title>
<programlisting># coredumpctl gdb</programlisting>
</example>
</example>
<example>
- <title>Extract the last coredump of /usr/bin/bar to a file named
+ <title>Extract the last core dump of /usr/bin/bar to a file named
<filename noindex="true">bar.coredump</filename></title>
<programlisting># coredumpctl -o bar.coredump dump /usr/bin/bar</programlisting>
<refname>systemd-coredump</refname>
<refname>systemd-coredump.socket</refname>
<refname>systemd-coredump@.service</refname>
- <refpurpose>Log and store core dumps</refpurpose>
+ <refpurpose>Acquire, save and process core dumps</refpurpose>
</refnamediv>
<refsynopsisdiv>
<refsect1>
<title>Description</title>
+ <para><command>systemd-coredump</command> is a system service that can acquire core dumps
+ from the kernel and handle them in various ways.</para>
- <para><command>systemd-coredump</command> can be used as a helper
- binary by the kernel when a user space program receives a fatal
- signal and dumps core. For it to be used in this capacity, it must
- be specified by the
- <varname>kernel.core_pattern</varname> <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- setting. The syntax of this setting is explained in
- <citerefentry project='man-pages'><refentrytitle>core</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
- Systemd installs <filename>/usr/lib/sysctl.d/50-coredump.conf</filename> which configures
- <varname>kernel.core_pattern</varname> to invoke <command>systemd-coredump</command>.
- This file may be masked or overridden to use a different setting following normal
- <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- rules.</para>
-
- <para>The behavior of a specific program upon reception of a
- signal is governed by a few factors which are described in detail
- in <citerefentry project='man-pages'><refentrytitle>core</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
- In particular, the coredump will only be processed when the
- related resource limits are high enough. For programs started by
- <command>systemd</command>, those may be set using
- <varname>LimitCore=</varname> (see
- <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
+ <para>Core dumps can be written to the journal or saved as a file. Once saved they can be retrieved
+ for further processing, for example in
+ <citerefentry project='man-pages'><refentrytitle>gdb</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
- <para>The behaviour of <command>systemd-coredump</command> is configured through
- <filename>/etc/systemd/coredump.conf</filename> and other configuration files. See
- <citerefentry><refentrytitle>coredump.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- for details. By default, <command>systemd-coredump</command> will log the coredump including a
- backtrace if possible, and store the core (contents of process' memory contents) in an external
- file on disk in <filename>/var/lib/systemd/coredump</filename>.</para>
+ <para>By default, <command>systemd-coredump</command> will log the core dump including a backtrace
+ if possible to the journal and store the core dump itself in an external file in
+ <filename>/var/lib/systemd/coredump</filename>.</para>
- <para>When the kernel invokes <command>systemd-coredump</command> to handle a coredump,
+ <para>When the kernel invokes <command>systemd-coredump</command> to handle a core dump,
it will connect to the socket created by the <filename>systemd-coredump.socket</filename>
unit, which in turn will spawn a <filename>systemd-coredump@.service</filename> instance
- to process the coredump. Hence <filename>systemd-coredump.socket</filename>
+ to process the core dump. Hence <filename>systemd-coredump.socket</filename>
and <filename>systemd-coredump@.service</filename> are helper units which do the actual
- processing of coredumps and are subject to normal service management.</para>
+ processing of core dumps and are subject to normal service management.</para>
- <para>The log entry and a backtrace are stored in the journal, and can be viewed with
- <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
- <citerefentry><refentrytitle>coredumpctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- may be used to list and extract coredumps or load them in
- <citerefentry project='man-pages'><refentrytitle>gdb</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+ <para>The behavior of a specific program upon reception of a signal is governed by a few
+ factors which are described in detail in
+ <citerefentry project='man-pages'><refentrytitle>core</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ In particular, the core dump will only be processed when the related resource limits are sufficient.
</para>
+ </refsect1>
- <para>The coredump helper is invoked anew each time. Therefore, any configuration
- changes will take effect on the invocation of <command>systemd-coredump</command>.
+ <refsect1>
+ <title>Configuration</title>
+ <para>For programs started by <command>systemd</command> process resource limits can be set by directive
+ <varname>LimitCore=</varname>, see
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ </para>
+
+ <para>In order to be used <command>systemd-coredump</command> must be configured in
+ <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ parameter <varname>kernel.core_pattern</varname>. The syntax of this parameter is explained in
+ <citerefentry project='man-pages'><refentrytitle>core</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ Systemd installs the file <filename>/usr/lib/sysctl.d/50-coredump.conf</filename> which configures
+ <varname>kernel.core_pattern</varname> accordingly. This file may be masked or overridden to use a different
+ setting following normal
+ <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ rules.
If the sysctl configuration is modified, it must be updated in the kernel before
it takes effect, see
- <citerefentry><refentrytitle>systemd-sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
and
- <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
+ <citerefentry><refentrytitle>systemd-sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
+
+ <para>The behaviour of <command>systemd-coredump</command> itself is configured through the configuration file
+ <filename>/etc/systemd/coredump.conf</filename> and corresponding snippets
+ <filename>/etc/systemd/coredump.conf.d/*.conf</filename>, see
+ <citerefentry><refentrytitle>coredump.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. A new
+ instance of <command>systemd-coredump</command> is invoked upon receiving every core dump. Therefore, changes
+ in these files will take effect the next time a core dump is received.</para>
+
+ <para>Resources used by core dump files are restricted in two ways. Parameters like maximum size of acquired
+ core dumps and files can be set in files <filename>/etc/systemd/coredump.conf</filename> and snippets mentioned
+ above. In addition the storage time of core dump files is restricted by <command>systemd-tmpfiles</command>,
+ corresponding settings are by default in <filename>/usr/lib/tmpfiles.d/systemd.conf</filename>.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Usage</title>
+ <para>Data stored in the journal can be viewed with
+ <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ as usual.
+ <citerefentry><refentrytitle>coredumpctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ can be used to retrieve saved core dumps independent of their location, to display information and to process
+ them e.g. by passing to the GNU debugger (gdb).</para>
</refsect1>
<refsect1>
<citerefentry><refentrytitle>coredump.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>coredumpctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>core</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-sysctl.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
projects / thirdparty / systemd.git / commitdiff
