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| -rw-r--r-- | man/systemd-coredump.xml | 47 |
1 files changed, 34 insertions, 13 deletions
diff --git a/man/systemd-coredump.xml b/man/systemd-coredump.xml index 4a1bc8b296..7243467dc2 100644 --- a/man/systemd-coredump.xml +++ b/man/systemd-coredump.xml @@ -52,14 +52,26 @@ <refsynopsisdiv> <para><filename>/usr/lib/systemd/systemd-coredump</filename></para> + <para><filename>/usr/lib/systemd/systemd-coredump</filename> <option>--backtrace</option></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><filename>systemd-coredump@.service</filename> is a system service that can acquire core + dumps from the kernel and handle them in various ways. The <command>systemd-coredump</command> + executable does the actual work. It is invoked twice: once as the handler by the kernel, and the + second time in the <filename>systemd-coredump@.service</filename> to actually write the data to + the journal.</para> + + <para>When the kernel invokes <command>systemd-coredump</command> to handle a core dump, it runs + in privileged mode, and will connect to the socket created by the + <filename>systemd-coredump.socket</filename> unit, which in turn will spawn an unprivileged + <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>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 @@ -70,18 +82,20 @@ 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> + + <para>It is also possible to invoke <command>systemd-coredump</command> with + <option>--backtrace</option> option. In this case, <command>systemd-coredump</command> expects + a journal entry in the journal + <ulink url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal Export Format</ulink> + on standard input. The entry should contain a <varname>MESSAGE=</varname> field and any additional + metadata fields the caller deems reasonable. <command>systemd-coredump</command> will append + additional metadata fields in the same way it does for core dumps received from the kernel. In + this mode, no core dump is stored in the journal.</para> </refsect1> <refsect1> @@ -91,7 +105,8 @@ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>. </para> - <para>In order to be used <command>systemd-coredump</command> must be configured in + <para>In order to be used by the kernel to handle core dumps, + <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>. @@ -99,14 +114,20 @@ <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 + 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>In order to by used in the <option>--backtrace</option> mode, an appropriate backtrace + handler must be installed on the sender side. For example, in case of + <citerefentry><refentrytitle>python</refentrytitle><manvolnum>1</manvolnum></citerefentry>, this + means a <varname>sys.excepthook</varname> must installed, see + <ulink url="https://github.com/keszybz/systemd-coredump-python">systemd-coredump-python</ulink>. + </para> + <para>The behavior 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 |