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Diffstat (limited to 'man/systemd-coredump.xml')
| -rw-r--r-- | man/systemd-coredump.xml | 100 |
1 files changed, 70 insertions, 30 deletions
diff --git a/man/systemd-coredump.xml b/man/systemd-coredump.xml index f1598461ef..a28dc62e5a 100644 --- a/man/systemd-coredump.xml +++ b/man/systemd-coredump.xml @@ -45,50 +45,89 @@ <refnamediv> <refname>systemd-coredump</refname> - <refpurpose>Log and store core dumps</refpurpose> + <refname>systemd-coredump.socket</refname> + <refname>systemd-coredump@.service</refname> + <refpurpose>Acquire, save and process core dumps</refpurpose> </refnamediv> <refsynopsisdiv> <para><filename>/usr/lib/systemd/systemd-coredump</filename></para> + <para><filename>systemd-coredump@.service</filename></para> + <para><filename>systemd-coredump.socket</filename></para> </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. 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><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>, or directly in - the journal. This behavior may be modified using - <citerefentry><refentrytitle>coredump.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</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 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 core dump. Hence <filename>systemd-coredump.socket</filename> + and <filename>systemd-coredump@.service</filename> are helper units which do the actual + processing of core dumps and are subject to normal service management.</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 core dump will only be processed when the related resource limits are sufficient. + </para> + </refsect1> + + <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>Apart from the + <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 project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry> + and + <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> - log viewer, + as usual. <citerefentry><refentrytitle>coredumpctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> - may be used to list and extract coredumps.</para> + 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> @@ -97,6 +136,7 @@ <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>. |