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man: improve description of environment block creation
This adds a general description of "philosphy" of keeping the environemnt block small and hints about systemd-run -P env. The list of generated variables is split out to a subsection. Viewing the patch with ignoring whitespace changes is recommended. We don't ignore invalid assignments (except in import-environment to some extent), previous description was wrong. For https://bugzilla.redhat.com/show_bug.cgi?id=1912046#c17.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
parent
a084b38789
commit
82651d5b6b
@ -1123,10 +1123,12 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
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<listitem>
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<para>Import all, one or more environment variables set on the client into the systemd manager
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environment block. If no arguments are passed, the entire environment block is imported.
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Otherwise, a list of one or more environment variable names should be passed, whose client-side
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values are then imported into the manager's environment block. This command will silently ignore
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any assignments which do not conform to the rules listed above.</para>
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environment block. If a list of environment variable names is passed, client-side values are then
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imported into the manager's environment block. If any names are not valid environment variable
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names or have invalid values according to the rules described above, an error is raised. If no
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arguments are passed, the entire environment block inherited by the <command>systemctl</command>
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process is imported. In this mode, any inherited invalid environment variables are quietly
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ignored.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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@ -2304,10 +2304,10 @@ SystemCallErrorNumber=EPERM</programlisting>
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set by the service manager itself (such as <varname>$NOTIFY_SOCKET</varname> and such), or set by a PAM module
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(in case <varname>PAMName=</varname> is used).</para>
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<para>
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See <citerefentry
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project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details
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about environment variables.</para></listitem>
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<para>See "Environment Variables in Spawned Processes" below for a description of how those
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settings combine to form the inherited environment. See <citerefentry
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project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry> for general
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information about environment variables.</para></listitem>
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</varlistentry>
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</variablelist>
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@ -2809,7 +2809,7 @@ StandardInputData=SWNrIHNpdHplIGRhIHVuJyBlc3NlIEtsb3BzLAp1ZmYgZWVtYWwga2xvcHAncy
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</refsect1>
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<refsect1>
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<title>Environment variables in spawned processes</title>
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<title>Environment Variables in Spawned Processes</title>
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<para>Processes started by the service manager are executed with an environment variable block assembled from
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multiple sources. Processes started by the system service manager generally do not inherit environment variables
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@ -2822,410 +2822,427 @@ StandardInputData=SWNrIHNpdHplIGRhIHVuJyBlc3NlIEtsb3BzLAp1ZmYgZWVtYWwga2xvcHAncy
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<itemizedlist>
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<listitem><para>Variables globally configured for the service manager, using the
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<varname>DefaultEnvironment=</varname> setting in
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<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, the kernel command line option <varname>systemd.setenv=</varname> (see
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>) or via
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<command>systemctl set-environment</command> (see <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>).</para></listitem>
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<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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the kernel command line option <varname>systemd.setenv=</varname> understood by
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, or via
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<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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<command>set-environment</command> verb.</para></listitem>
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<listitem><para>Variables defined by the service manager itself (see the list below)</para></listitem>
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<listitem><para>Variables defined by the service manager itself (see the list below).</para></listitem>
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<listitem><para>Variables set in the service manager's own environment variable block (subject to <varname>PassEnvironment=</varname> for the system service manager)</para></listitem>
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<listitem><para>Variables set in the service manager's own environment variable block (subject to
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<varname>PassEnvironment=</varname> for the system service manager).</para></listitem>
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<listitem><para>Variables set via <varname>Environment=</varname> in the unit file</para></listitem>
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<listitem><para>Variables set via <varname>Environment=</varname> in the unit file.</para></listitem>
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<listitem><para>Variables read from files specified via <varname>EnvironmentFile=</varname> in the unit file</para></listitem>
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<listitem><para>Variables read from files specified via <varname>EnvironmentFile=</varname> in the unit
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file.</para></listitem>
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<listitem><para>Variables set by any PAM modules in case <varname>PAMName=</varname> is in effect,
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cf. <citerefentry
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project='man-pages'><refentrytitle>pam_env</refentrytitle><manvolnum>8</manvolnum></citerefentry></para></listitem>
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project='man-pages'><refentrytitle>pam_env</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
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</para></listitem>
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</itemizedlist>
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<para>If the same environment variables are set by multiple of these sources, the later source — according to the
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order of the list above — wins. Note that as final step all variables listed in
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<varname>UnsetEnvironment=</varname> are removed again from the compiled environment variable list, immediately
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<para>If the same environment variable is set by multiple of these sources, the later source — according
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to the order of the list above — wins. Note that as the final step all variables listed in
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<varname>UnsetEnvironment=</varname> are removed from the compiled environment variable list, immediately
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before it is passed to the executed process.</para>
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<para>The following environment variables are set or propagated by the service manager for each invoked
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process:</para>
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<para>The general philosophy is to expose a small curated list of environment variables to processes.
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Services started by the system manager (PID 1) will be started, without additional service-specific
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configuration, with just a few environment variables. The user manager inherits environment variables as
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any other system service, but in addition may receive additional environment variables from PAM, and,
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typically, additional imported variables when the user starts a graphical session. It is recommended to
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keep the environment blocks in both the system and user managers managers lean.</para>
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<variablelist class='environment-variables'>
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<varlistentry>
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<term><varname>$PATH</varname></term>
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<para>Hint: <command>systemd-run -P env</command> and <command>systemd-run --user -P env</command> print
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the effective system and user service environment blocks.</para>
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<listitem><para>Colon-separated list of directories to use when launching
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executables. <command>systemd</command> uses a fixed value of
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<literal><filename>/usr/local/sbin</filename>:<filename>/usr/local/bin</filename>:<filename>/usr/sbin</filename>:<filename>/usr/bin</filename></literal>
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in the system manager. When compiled for systems with "unmerged /usr" (<filename>/bin</filename> is
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not a symlink to <filename>/usr/bin</filename>),
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<literal>:<filename>/sbin</filename>:<filename>/bin</filename></literal> is appended. In case of the
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the user manager, a different path may be configured by the distribution. It is recommended to not
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rely on the order of entries, and have only one program with a given name in
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<varname>$PATH</varname>.</para></listitem>
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</varlistentry>
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<refsect2>
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<title>Environment Variables Set or Propagated by the Service Manager</title>
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<varlistentry>
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<term><varname>$LANG</varname></term>
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<para>The following environment variables are propagated by the service manager or generated internally
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for each invoked process:</para>
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<listitem><para>Locale. Can be set in
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<citerefentry project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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or on the kernel command line (see
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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and
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<citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>).
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</para></listitem>
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</varlistentry>
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<variablelist class='environment-variables'>
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<varlistentry>
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<term><varname>$PATH</varname></term>
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<varlistentry>
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<term><varname>$USER</varname></term>
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<term><varname>$LOGNAME</varname></term>
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<term><varname>$HOME</varname></term>
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<term><varname>$SHELL</varname></term>
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<listitem><para>Colon-separated list of directories to use when launching
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executables. <command>systemd</command> uses a fixed value of
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<literal><filename>/usr/local/sbin</filename>:<filename>/usr/local/bin</filename>:<filename>/usr/sbin</filename>:<filename>/usr/bin</filename></literal>
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in the system manager. When compiled for systems with "unmerged <filename>/usr/</filename>"
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(<filename>/bin</filename> is not a symlink to <filename>/usr/bin</filename>),
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<literal>:<filename>/sbin</filename>:<filename>/bin</filename></literal> is appended. In case of
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the the user manager, a different path may be configured by the distribution. It is recommended to
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not rely on the order of entries, and have only one program with a given name in
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<varname>$PATH</varname>.</para></listitem>
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</varlistentry>
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<listitem><para>User name (twice), home directory, and the
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login shell. The variables are set for the units that have
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<varname>User=</varname> set, which includes user
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<command>systemd</command> instances. See
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<citerefentry project='die-net'><refentrytitle>passwd</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>$LANG</varname></term>
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<varlistentry>
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<term><varname>$INVOCATION_ID</varname></term>
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<listitem><para>Locale. Can be set in <citerefentry
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project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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or on the kernel command line (see
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> and
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<citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>).
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</para></listitem>
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</varlistentry>
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<listitem><para>Contains a randomized, unique 128bit ID identifying each runtime cycle of the unit, formatted
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as 32 character hexadecimal string. A new ID is assigned each time the unit changes from an inactive state into
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an activating or active state, and may be used to identify this specific runtime cycle, in particular in data
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stored offline, such as the journal. The same ID is passed to all processes run as part of the
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unit.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>$USER</varname></term>
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<term><varname>$LOGNAME</varname></term>
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<term><varname>$HOME</varname></term>
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<term><varname>$SHELL</varname></term>
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<varlistentry>
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<term><varname>$XDG_RUNTIME_DIR</varname></term>
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<listitem><para>User name (twice), home directory, and the
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login shell. The variables are set for the units that have
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<varname>User=</varname> set, which includes user
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<command>systemd</command> instances. See
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<citerefentry project='die-net'><refentrytitle>passwd</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
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</para></listitem>
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</varlistentry>
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<listitem><para>The directory to use for runtime objects (such as IPC objects) and volatile state. Set for all
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services run by the user <command>systemd</command> instance, as well as any system services that use
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<varname>PAMName=</varname> with a PAM stack that includes <command>pam_systemd</command>. See below and
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<citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry> for more
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information.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>$INVOCATION_ID</varname></term>
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<varlistentry>
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<term><varname>$RUNTIME_DIRECTORY</varname></term>
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<term><varname>$STATE_DIRECTORY</varname></term>
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<term><varname>$CACHE_DIRECTORY</varname></term>
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<term><varname>$LOGS_DIRECTORY</varname></term>
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<term><varname>$CONFIGURATION_DIRECTORY</varname></term>
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<listitem><para>Contains a randomized, unique 128bit ID identifying each runtime cycle of the unit, formatted
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as 32 character hexadecimal string. A new ID is assigned each time the unit changes from an inactive state into
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an activating or active state, and may be used to identify this specific runtime cycle, in particular in data
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stored offline, such as the journal. The same ID is passed to all processes run as part of the
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unit.</para></listitem>
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</varlistentry>
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<listitem><para>Absolute paths to the directories defined with
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<varname>RuntimeDirectory=</varname>, <varname>StateDirectory=</varname>,
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<varname>CacheDirectory=</varname>, <varname>LogsDirectory=</varname>, and
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<varname>ConfigurationDirectory=</varname> when those settings are used.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>$XDG_RUNTIME_DIR</varname></term>
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<varlistentry>
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<term><varname>$CREDENTIALS_DIRECTORY</varname></term>
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<listitem><para>The directory to use for runtime objects (such as IPC objects) and volatile state. Set for all
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services run by the user <command>systemd</command> instance, as well as any system services that use
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<varname>PAMName=</varname> with a PAM stack that includes <command>pam_systemd</command>. See below and
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<citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry> for more
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information.</para></listitem>
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</varlistentry>
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<listitem><para>An absolute path to the per-unit directory with credentials configured via
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<varname>LoadCredential=</varname>/<varname>SetCredential=</varname>. The directory is marked
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read-only and is placed in unswappable memory (if supported and permitted), and is only accessible to
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the UID associated with the unit via <varname>User=</varname> or <varname>DynamicUser=</varname> (and
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the superuser).</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>$RUNTIME_DIRECTORY</varname></term>
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<term><varname>$STATE_DIRECTORY</varname></term>
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<term><varname>$CACHE_DIRECTORY</varname></term>
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<term><varname>$LOGS_DIRECTORY</varname></term>
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<term><varname>$CONFIGURATION_DIRECTORY</varname></term>
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<varlistentry>
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<term><varname>$MAINPID</varname></term>
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<listitem><para>Absolute paths to the directories defined with
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<varname>RuntimeDirectory=</varname>, <varname>StateDirectory=</varname>,
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<varname>CacheDirectory=</varname>, <varname>LogsDirectory=</varname>, and
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<varname>ConfigurationDirectory=</varname> when those settings are used.</para>
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</listitem>
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</varlistentry>
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<listitem><para>The PID of the unit's main process if it is
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known. This is only set for control processes as invoked by
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<varname>ExecReload=</varname> and similar. </para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>$CREDENTIALS_DIRECTORY</varname></term>
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<varlistentry>
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<term><varname>$MANAGERPID</varname></term>
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<listitem><para>An absolute path to the per-unit directory with credentials configured via
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<varname>LoadCredential=</varname>/<varname>SetCredential=</varname>. The directory is marked
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read-only and is placed in unswappable memory (if supported and permitted), and is only accessible to
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the UID associated with the unit via <varname>User=</varname> or <varname>DynamicUser=</varname> (and
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the superuser).</para></listitem>
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</varlistentry>
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<listitem><para>The PID of the user <command>systemd</command>
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instance, set for processes spawned by it. </para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>$MAINPID</varname></term>
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<varlistentry>
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<term><varname>$LISTEN_FDS</varname></term>
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<term><varname>$LISTEN_PID</varname></term>
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<term><varname>$LISTEN_FDNAMES</varname></term>
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<listitem><para>The PID of the unit's main process if it is
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known. This is only set for control processes as invoked by
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<varname>ExecReload=</varname> and similar. </para></listitem>
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</varlistentry>
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<listitem><para>Information about file descriptors passed to a
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service for socket activation. See
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<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>$MANAGERPID</varname></term>
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<varlistentry>
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<term><varname>$NOTIFY_SOCKET</varname></term>
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<listitem><para>The PID of the user <command>systemd</command>
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instance, set for processes spawned by it. </para></listitem>
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</varlistentry>
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<listitem><para>The socket
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<function>sd_notify()</function> talks to. See
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<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>$LISTEN_FDS</varname></term>
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<term><varname>$LISTEN_PID</varname></term>
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<term><varname>$LISTEN_FDNAMES</varname></term>
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<varlistentry>
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<term><varname>$WATCHDOG_PID</varname></term>
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<term><varname>$WATCHDOG_USEC</varname></term>
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<listitem><para>Information about file descriptors passed to a
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service for socket activation. See
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<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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</para></listitem>
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</varlistentry>
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<listitem><para>Information about watchdog keep-alive notifications. See
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<citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>$NOTIFY_SOCKET</varname></term>
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<varlistentry>
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<term><varname>$TERM</varname></term>
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<listitem><para>The socket
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<function>sd_notify()</function> talks to. See
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<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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</para></listitem>
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</varlistentry>
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<listitem><para>Terminal type, set only for units connected to
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a terminal (<varname>StandardInput=tty</varname>,
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<varname>StandardOutput=tty</varname>, or
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<varname>StandardError=tty</varname>). See
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<citerefentry project='man-pages'><refentrytitle>termcap</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>$WATCHDOG_PID</varname></term>
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<term><varname>$WATCHDOG_USEC</varname></term>
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<varlistentry>
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<term><varname>$LOG_NAMESPACE</varname></term>
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<listitem><para>Information about watchdog keep-alive notifications. See
|
||||
<citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
|
||||
</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<listitem><para>Contains the name of the selected logging namespace when the
|
||||
<varname>LogNamespace=</varname> service setting is used.</para></listitem>
|
||||
</varlistentry>
|
||||
<varlistentry>
|
||||
<term><varname>$TERM</varname></term>
|
||||
|
||||
<varlistentry>
|
||||
<term><varname>$JOURNAL_STREAM</varname></term>
|
||||
<listitem><para>Terminal type, set only for units connected to
|
||||
a terminal (<varname>StandardInput=tty</varname>,
|
||||
<varname>StandardOutput=tty</varname>, or
|
||||
<varname>StandardError=tty</varname>). See
|
||||
<citerefentry project='man-pages'><refentrytitle>termcap</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
|
||||
</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<listitem><para>If the standard output or standard error output of the executed processes are connected to the
|
||||
journal (for example, by setting <varname>StandardError=journal</varname>) <varname>$JOURNAL_STREAM</varname>
|
||||
contains the device and inode numbers of the connection file descriptor, formatted in decimal, separated by a
|
||||
colon (<literal>:</literal>). This permits invoked processes to safely detect whether their standard output or
|
||||
standard error output are connected to the journal. The device and inode numbers of the file descriptors should
|
||||
be compared with the values set in the environment variable to determine whether the process output is still
|
||||
connected to the journal. Note that it is generally not sufficient to only check whether
|
||||
<varname>$JOURNAL_STREAM</varname> is set at all as services might invoke external processes replacing their
|
||||
standard output or standard error output, without unsetting the environment variable.</para>
|
||||
<varlistentry>
|
||||
<term><varname>$LOG_NAMESPACE</varname></term>
|
||||
|
||||
<para>If both standard output and standard error of the executed processes are connected to the journal via a
|
||||
stream socket, this environment variable will contain information about the standard error stream, as that's
|
||||
usually the preferred destination for log data. (Note that typically the same stream is used for both standard
|
||||
output and standard error, hence very likely the environment variable contains device and inode information
|
||||
matching both stream file descriptors.)</para>
|
||||
<listitem><para>Contains the name of the selected logging namespace when the
|
||||
<varname>LogNamespace=</varname> service setting is used.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<para>This environment variable is primarily useful to allow services to optionally upgrade their used log
|
||||
protocol to the native journal protocol (using
|
||||
<citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry> and other
|
||||
functions) if their standard output or standard error output is connected to the journal anyway, thus enabling
|
||||
delivery of structured metadata along with logged messages.</para></listitem>
|
||||
</varlistentry>
|
||||
<varlistentry>
|
||||
<term><varname>$JOURNAL_STREAM</varname></term>
|
||||
|
||||
<varlistentry>
|
||||
<term><varname>$SERVICE_RESULT</varname></term>
|
||||
<listitem><para>If the standard output or standard error output of the executed processes are connected to the
|
||||
journal (for example, by setting <varname>StandardError=journal</varname>) <varname>$JOURNAL_STREAM</varname>
|
||||
contains the device and inode numbers of the connection file descriptor, formatted in decimal, separated by a
|
||||
colon (<literal>:</literal>). This permits invoked processes to safely detect whether their standard output or
|
||||
standard error output are connected to the journal. The device and inode numbers of the file descriptors should
|
||||
be compared with the values set in the environment variable to determine whether the process output is still
|
||||
connected to the journal. Note that it is generally not sufficient to only check whether
|
||||
<varname>$JOURNAL_STREAM</varname> is set at all as services might invoke external processes replacing their
|
||||
standard output or standard error output, without unsetting the environment variable.</para>
|
||||
|
||||
<listitem><para>Only defined for the service unit type, this environment variable is passed to all
|
||||
<varname>ExecStop=</varname> and <varname>ExecStopPost=</varname> processes, and encodes the service
|
||||
"result". Currently, the following values are defined:</para>
|
||||
<para>If both standard output and standard error of the executed processes are connected to the journal via a
|
||||
stream socket, this environment variable will contain information about the standard error stream, as that's
|
||||
usually the preferred destination for log data. (Note that typically the same stream is used for both standard
|
||||
output and standard error, hence very likely the environment variable contains device and inode information
|
||||
matching both stream file descriptors.)</para>
|
||||
|
||||
<table>
|
||||
<title>Defined <varname>$SERVICE_RESULT</varname> values</title>
|
||||
<tgroup cols='2'>
|
||||
<colspec colname='result'/>
|
||||
<colspec colname='meaning'/>
|
||||
<thead>
|
||||
<row>
|
||||
<entry>Value</entry>
|
||||
<entry>Meaning</entry>
|
||||
</row>
|
||||
</thead>
|
||||
<para>This environment variable is primarily useful to allow services to optionally upgrade their used log
|
||||
protocol to the native journal protocol (using
|
||||
<citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry> and other
|
||||
functions) if their standard output or standard error output is connected to the journal anyway, thus enabling
|
||||
delivery of structured metadata along with logged messages.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<tbody>
|
||||
<row>
|
||||
<entry><literal>success</literal></entry>
|
||||
<entry>The service ran successfully and exited cleanly.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>protocol</literal></entry>
|
||||
<entry>A protocol violation occurred: the service did not take the steps required by its unit configuration (specifically what is configured in its <varname>Type=</varname> setting).</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>timeout</literal></entry>
|
||||
<entry>One of the steps timed out.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>exit-code</literal></entry>
|
||||
<entry>Service process exited with a non-zero exit code; see <varname>$EXIT_CODE</varname> below for the actual exit code returned.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>signal</literal></entry>
|
||||
<entry>A service process was terminated abnormally by a signal, without dumping core. See <varname>$EXIT_CODE</varname> below for the actual signal causing the termination.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>core-dump</literal></entry>
|
||||
<entry>A service process terminated abnormally with a signal and dumped core. See <varname>$EXIT_CODE</varname> below for the signal causing the termination.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>watchdog</literal></entry>
|
||||
<entry>Watchdog keep-alive ping was enabled for the service, but the deadline was missed.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>start-limit-hit</literal></entry>
|
||||
<entry>A start limit was defined for the unit and it was hit, causing the unit to fail to start. See <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s <varname>StartLimitIntervalSec=</varname> and <varname>StartLimitBurst=</varname> for details.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>resources</literal></entry>
|
||||
<entry>A catch-all condition in case a system operation failed.</entry>
|
||||
</row>
|
||||
</tbody>
|
||||
</tgroup>
|
||||
</table>
|
||||
<varlistentry>
|
||||
<term><varname>$SERVICE_RESULT</varname></term>
|
||||
|
||||
<para>This environment variable is useful to monitor failure or successful termination of a service. Even
|
||||
though this variable is available in both <varname>ExecStop=</varname> and <varname>ExecStopPost=</varname>, it
|
||||
is usually a better choice to place monitoring tools in the latter, as the former is only invoked for services
|
||||
that managed to start up correctly, and the latter covers both services that failed during their start-up and
|
||||
those which failed during their runtime.</para></listitem>
|
||||
</varlistentry>
|
||||
<listitem><para>Only defined for the service unit type, this environment variable is passed to all
|
||||
<varname>ExecStop=</varname> and <varname>ExecStopPost=</varname> processes, and encodes the service
|
||||
"result". Currently, the following values are defined:</para>
|
||||
|
||||
<varlistentry>
|
||||
<term><varname>$EXIT_CODE</varname></term>
|
||||
<term><varname>$EXIT_STATUS</varname></term>
|
||||
<table>
|
||||
<title>Defined <varname>$SERVICE_RESULT</varname> values</title>
|
||||
<tgroup cols='2'>
|
||||
<colspec colname='result'/>
|
||||
<colspec colname='meaning'/>
|
||||
<thead>
|
||||
<row>
|
||||
<entry>Value</entry>
|
||||
<entry>Meaning</entry>
|
||||
</row>
|
||||
</thead>
|
||||
|
||||
<listitem><para>Only defined for the service unit type, these environment variables are passed to all
|
||||
<varname>ExecStop=</varname>, <varname>ExecStopPost=</varname> processes and contain exit status/code
|
||||
information of the main process of the service. For the precise definition of the exit code and status, see
|
||||
<citerefentry><refentrytitle>wait</refentrytitle><manvolnum>2</manvolnum></citerefentry>. <varname>$EXIT_CODE</varname>
|
||||
is one of <literal>exited</literal>, <literal>killed</literal>,
|
||||
<literal>dumped</literal>. <varname>$EXIT_STATUS</varname> contains the numeric exit code formatted as string
|
||||
if <varname>$EXIT_CODE</varname> is <literal>exited</literal>, and the signal name in all other cases. Note
|
||||
that these environment variables are only set if the service manager succeeded to start and identify the main
|
||||
process of the service.</para>
|
||||
<tbody>
|
||||
<row>
|
||||
<entry><literal>success</literal></entry>
|
||||
<entry>The service ran successfully and exited cleanly.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>protocol</literal></entry>
|
||||
<entry>A protocol violation occurred: the service did not take the steps required by its unit configuration (specifically what is configured in its <varname>Type=</varname> setting).</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>timeout</literal></entry>
|
||||
<entry>One of the steps timed out.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>exit-code</literal></entry>
|
||||
<entry>Service process exited with a non-zero exit code; see <varname>$EXIT_CODE</varname> below for the actual exit code returned.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>signal</literal></entry>
|
||||
<entry>A service process was terminated abnormally by a signal, without dumping core. See <varname>$EXIT_CODE</varname> below for the actual signal causing the termination.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>core-dump</literal></entry>
|
||||
<entry>A service process terminated abnormally with a signal and dumped core. See <varname>$EXIT_CODE</varname> below for the signal causing the termination.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>watchdog</literal></entry>
|
||||
<entry>Watchdog keep-alive ping was enabled for the service, but the deadline was missed.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>start-limit-hit</literal></entry>
|
||||
<entry>A start limit was defined for the unit and it was hit, causing the unit to fail to start. See <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s <varname>StartLimitIntervalSec=</varname> and <varname>StartLimitBurst=</varname> for details.</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>resources</literal></entry>
|
||||
<entry>A catch-all condition in case a system operation failed.</entry>
|
||||
</row>
|
||||
</tbody>
|
||||
</tgroup>
|
||||
</table>
|
||||
|
||||
<table>
|
||||
<title>Summary of possible service result variable values</title>
|
||||
<tgroup cols='3'>
|
||||
<colspec colname='result' />
|
||||
<colspec colname='code' />
|
||||
<colspec colname='status' />
|
||||
<thead>
|
||||
<row>
|
||||
<entry><varname>$SERVICE_RESULT</varname></entry>
|
||||
<entry><varname>$EXIT_CODE</varname></entry>
|
||||
<entry><varname>$EXIT_STATUS</varname></entry>
|
||||
</row>
|
||||
</thead>
|
||||
<para>This environment variable is useful to monitor failure or successful termination of a service. Even
|
||||
though this variable is available in both <varname>ExecStop=</varname> and <varname>ExecStopPost=</varname>, it
|
||||
is usually a better choice to place monitoring tools in the latter, as the former is only invoked for services
|
||||
that managed to start up correctly, and the latter covers both services that failed during their start-up and
|
||||
those which failed during their runtime.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<tbody>
|
||||
<row>
|
||||
<entry morerows="1" valign="top"><literal>success</literal></entry>
|
||||
<entry valign="top"><literal>killed</literal></entry>
|
||||
<entry><literal>HUP</literal>, <literal>INT</literal>, <literal>TERM</literal>, <literal>PIPE</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>exited</literal></entry>
|
||||
<entry><literal>0</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry morerows="1" valign="top"><literal>protocol</literal></entry>
|
||||
<entry valign="top">not set</entry>
|
||||
<entry>not set</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>exited</literal></entry>
|
||||
<entry><literal>0</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry morerows="1" valign="top"><literal>timeout</literal></entry>
|
||||
<entry valign="top"><literal>killed</literal></entry>
|
||||
<entry><literal>TERM</literal>, <literal>KILL</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>exited</literal></entry>
|
||||
<entry><literal>0</literal>, <literal>1</literal>, <literal>2</literal>, <literal
|
||||
>3</literal>, …, <literal>255</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>exit-code</literal></entry>
|
||||
<entry valign="top"><literal>exited</literal></entry>
|
||||
<entry><literal>1</literal>, <literal>2</literal>, <literal
|
||||
>3</literal>, …, <literal>255</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>signal</literal></entry>
|
||||
<entry valign="top"><literal>killed</literal></entry>
|
||||
<entry><literal>HUP</literal>, <literal>INT</literal>, <literal>KILL</literal>, …</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>core-dump</literal></entry>
|
||||
<entry valign="top"><literal>dumped</literal></entry>
|
||||
<entry><literal>ABRT</literal>, <literal>SEGV</literal>, <literal>QUIT</literal>, …</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry morerows="2" valign="top"><literal>watchdog</literal></entry>
|
||||
<entry><literal>dumped</literal></entry>
|
||||
<entry><literal>ABRT</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>killed</literal></entry>
|
||||
<entry><literal>TERM</literal>, <literal>KILL</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>exited</literal></entry>
|
||||
<entry><literal>0</literal>, <literal>1</literal>, <literal>2</literal>, <literal
|
||||
>3</literal>, …, <literal>255</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>exec-condition</literal></entry>
|
||||
<entry><literal>exited</literal></entry>
|
||||
<entry><literal>1</literal>, <literal>2</literal>, <literal>3</literal>, <literal
|
||||
>4</literal>, …, <literal>254</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>oom-kill</literal></entry>
|
||||
<entry valign="top"><literal>killed</literal></entry>
|
||||
<entry><literal>TERM</literal>, <literal>KILL</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>start-limit-hit</literal></entry>
|
||||
<entry>not set</entry>
|
||||
<entry>not set</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>resources</literal></entry>
|
||||
<entry>any of the above</entry>
|
||||
<entry>any of the above</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry namest="results" nameend="status">Note: the process may be also terminated by a signal not sent by systemd. In particular the process may send an arbitrary signal to itself in a handler for any of the non-maskable signals. Nevertheless, in the <literal>timeout</literal> and <literal>watchdog</literal> rows above only the signals that systemd sends have been included. Moreover, using <varname>SuccessExitStatus=</varname> additional exit statuses may be declared to indicate clean termination, which is not reflected by this table.</entry>
|
||||
</row>
|
||||
</tbody>
|
||||
</tgroup>
|
||||
</table>
|
||||
<varlistentry>
|
||||
<term><varname>$EXIT_CODE</varname></term>
|
||||
<term><varname>$EXIT_STATUS</varname></term>
|
||||
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
<listitem><para>Only defined for the service unit type, these environment variables are passed to all
|
||||
<varname>ExecStop=</varname>, <varname>ExecStopPost=</varname> processes and contain exit status/code
|
||||
information of the main process of the service. For the precise definition of the exit code and status, see
|
||||
<citerefentry><refentrytitle>wait</refentrytitle><manvolnum>2</manvolnum></citerefentry>. <varname>$EXIT_CODE</varname>
|
||||
is one of <literal>exited</literal>, <literal>killed</literal>,
|
||||
<literal>dumped</literal>. <varname>$EXIT_STATUS</varname> contains the numeric exit code formatted as string
|
||||
if <varname>$EXIT_CODE</varname> is <literal>exited</literal>, and the signal name in all other cases. Note
|
||||
that these environment variables are only set if the service manager succeeded to start and identify the main
|
||||
process of the service.</para>
|
||||
|
||||
<varlistentry>
|
||||
<term><varname>$PIDFILE</varname></term>
|
||||
<table>
|
||||
<title>Summary of possible service result variable values</title>
|
||||
<tgroup cols='3'>
|
||||
<colspec colname='result' />
|
||||
<colspec colname='code' />
|
||||
<colspec colname='status' />
|
||||
<thead>
|
||||
<row>
|
||||
<entry><varname>$SERVICE_RESULT</varname></entry>
|
||||
<entry><varname>$EXIT_CODE</varname></entry>
|
||||
<entry><varname>$EXIT_STATUS</varname></entry>
|
||||
</row>
|
||||
</thead>
|
||||
|
||||
<listitem><para>The path to the configured PID file, in case the process is forked off on behalf of a
|
||||
service that uses the <varname>PIDFile=</varname> setting, see
|
||||
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
||||
for details. Service code may use this environment variable to automatically generate a PID file at
|
||||
the location configured in the unit file. This field is set to an absolute path in the file
|
||||
system.</para></listitem>
|
||||
</varlistentry>
|
||||
<tbody>
|
||||
<row>
|
||||
<entry morerows="1" valign="top"><literal>success</literal></entry>
|
||||
<entry valign="top"><literal>killed</literal></entry>
|
||||
<entry><literal>HUP</literal>, <literal>INT</literal>, <literal>TERM</literal>, <literal>PIPE</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>exited</literal></entry>
|
||||
<entry><literal>0</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry morerows="1" valign="top"><literal>protocol</literal></entry>
|
||||
<entry valign="top">not set</entry>
|
||||
<entry>not set</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>exited</literal></entry>
|
||||
<entry><literal>0</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry morerows="1" valign="top"><literal>timeout</literal></entry>
|
||||
<entry valign="top"><literal>killed</literal></entry>
|
||||
<entry><literal>TERM</literal>, <literal>KILL</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>exited</literal></entry>
|
||||
<entry><literal>0</literal>, <literal>1</literal>, <literal>2</literal>, <literal
|
||||
>3</literal>, …, <literal>255</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>exit-code</literal></entry>
|
||||
<entry valign="top"><literal>exited</literal></entry>
|
||||
<entry><literal>1</literal>, <literal>2</literal>, <literal
|
||||
>3</literal>, …, <literal>255</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>signal</literal></entry>
|
||||
<entry valign="top"><literal>killed</literal></entry>
|
||||
<entry><literal>HUP</literal>, <literal>INT</literal>, <literal>KILL</literal>, …</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>core-dump</literal></entry>
|
||||
<entry valign="top"><literal>dumped</literal></entry>
|
||||
<entry><literal>ABRT</literal>, <literal>SEGV</literal>, <literal>QUIT</literal>, …</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry morerows="2" valign="top"><literal>watchdog</literal></entry>
|
||||
<entry><literal>dumped</literal></entry>
|
||||
<entry><literal>ABRT</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>killed</literal></entry>
|
||||
<entry><literal>TERM</literal>, <literal>KILL</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>exited</literal></entry>
|
||||
<entry><literal>0</literal>, <literal>1</literal>, <literal>2</literal>, <literal
|
||||
>3</literal>, …, <literal>255</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>exec-condition</literal></entry>
|
||||
<entry><literal>exited</literal></entry>
|
||||
<entry><literal>1</literal>, <literal>2</literal>, <literal>3</literal>, <literal
|
||||
>4</literal>, …, <literal>254</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry valign="top"><literal>oom-kill</literal></entry>
|
||||
<entry valign="top"><literal>killed</literal></entry>
|
||||
<entry><literal>TERM</literal>, <literal>KILL</literal></entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>start-limit-hit</literal></entry>
|
||||
<entry>not set</entry>
|
||||
<entry>not set</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry><literal>resources</literal></entry>
|
||||
<entry>any of the above</entry>
|
||||
<entry>any of the above</entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry namest="results" nameend="status">Note: the process may be also terminated by a signal not sent by systemd. In particular the process may send an arbitrary signal to itself in a handler for any of the non-maskable signals. Nevertheless, in the <literal>timeout</literal> and <literal>watchdog</literal> rows above only the signals that systemd sends have been included. Moreover, using <varname>SuccessExitStatus=</varname> additional exit statuses may be declared to indicate clean termination, which is not reflected by this table.</entry>
|
||||
</row>
|
||||
</tbody>
|
||||
</tgroup>
|
||||
</table></listitem>
|
||||
</varlistentry>
|
||||
|
||||
</variablelist>
|
||||
<varlistentry>
|
||||
<term><varname>$PIDFILE</varname></term>
|
||||
|
||||
<listitem><para>The path to the configured PID file, in case the process is forked off on behalf of
|
||||
a service that uses the <varname>PIDFile=</varname> setting, see
|
||||
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
||||
for details. Service code may use this environment variable to automatically generate a PID file at
|
||||
the location configured in the unit file. This field is set to an absolute path in the file
|
||||
system.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
</variablelist>
|
||||
|
||||
<para>For system services, when <varname>PAMName=</varname> is enabled and <command>pam_systemd</command> is part
|
||||
of the selected PAM stack, additional environment variables defined by systemd may be set for
|
||||
services. Specifically, these are <varname>$XDG_SEAT</varname>, <varname>$XDG_VTNR</varname>, see
|
||||
<citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry> for details.</para>
|
||||
</refsect2>
|
||||
|
||||
<para>For system services, when <varname>PAMName=</varname> is enabled and <command>pam_systemd</command> is part
|
||||
of the selected PAM stack, additional environment variables defined by systemd may be set for
|
||||
services. Specifically, these are <varname>$XDG_SEAT</varname>, <varname>$XDG_VTNR</varname>, see
|
||||
<citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry> for details.</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>Process exit codes</title>
|
||||
<title>Process Exit Codes</title>
|
||||
|
||||
<para>When invoking a unit process the service manager possibly fails to apply the execution parameters configured
|
||||
with the settings above. In that case the already created service process will exit with a non-zero exit code
|
||||
|
||||
Loading…
Reference in New Issue
Block a user