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diff --git a/man/systemd.environment-generator.xml b/man/systemd.environment-generator.xml new file mode 100644 index 0000000000..fedbd60175 --- /dev/null +++ b/man/systemd.environment-generator.xml @@ -0,0 +1,160 @@ +<?xml version='1.0'?> <!--*-nxml-*--> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [ +<!ENTITY % entities SYSTEM "custom-entities.ent" > +%entities; +]> + +<!-- + This file is part of systemd. + + Copyright 2017 Zbigniew Jędrzejewski-Szmek + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +--> + +<refentry id="systemd.environment-generator" xmlns:xi="http://www.w3.org/2001/XInclude"> + <refentryinfo> + <title>systemd.environment-generator</title> + <productname>systemd</productname> + + <authorgroup> + <author> + <contrib>Developer</contrib> + <firstname>Zbigniew</firstname> + <surname>Jędrzejewski-Szmek</surname> + <email>zbyszek@in.waw.pl</email> + </author> + </authorgroup> + </refentryinfo> + + <refmeta> + <refentrytitle>systemd.environment-generator</refentrytitle> + <manvolnum>7</manvolnum> + </refmeta> + + <refnamediv> + <refname>systemd.environment-generator</refname> + <refpurpose>Systemd environment file generators</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <cmdsynopsis> + <command>&systemenvgeneratordir;/some-generator</command> + </cmdsynopsis> + <cmdsynopsis> + <command>&userenvgeneratordir;/some-generator</command> + </cmdsynopsis> + + <para> + <literallayout><filename>/run/systemd/system-environment-generators/*</filename> +<filename>/etc/systemd/system-environment-generators/*</filename> +<filename>/usr/local/lib/systemd/system-environment-generators/*</filename> +<filename>&systemenvgeneratordir;/*</filename></literallayout> + </para> + + <para> + <literallayout><filename>/run/systemd/user-environment-generators/*</filename> +<filename>/etc/systemd/user-environment-generators/*</filename> +<filename>/usr/local/lib/systemd/user-environment-generators/*</filename> +<filename>&userenvgeneratordir;/*</filename></literallayout> + </para> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + <para>Generators are small executables that live in + <filename>&systemenvgeneratordir;/</filename> and other directories listed above. + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> will + execute those binaries very early at the startup of each manager and at configuration + reload time, before running the generators described in + <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry> + and before starting any units. Environment generators can override the environment that the + manager exports to services and other processes.</para> + + <para>Generators are loaded from a set of paths determined during compilation, as listed + above. System and user environment generators are loaded from directories with names ending in + <filename>system-environment-generators/</filename> and + <filename>user-environment-generators/</filename>, respectively. Generators found in directories + listed earlier override the ones with the same name in directories lower in the list. A symlink + to <filename>/dev/null</filename> or an empty file can be used to mask a generator, thereby + preventing it from running. Please note that the order of the two directories with the highest + priority is reversed with respect to the unit load path, and generators in + <filename>/run</filename> overwrite those in <filename>/etc</filename>.</para> + + <para>After installing new generators or updating the configuration, <command>systemctl + daemon-reload</command> may be executed. This will re-run all generators, updating environment + configuration. It will be used for any services that are started subsequently.</para> + + <para>Environment file generators are executed similarly to unit file generators described + in + <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>, + with the following differences:</para> + + <itemizedlist> + <listitem> + <para>Generators are executed sequentially in the alphanumerical order of the final + component of their name. The output of each generator output is immediately parsed and used + to update the environment for generators that run after that. Thus, later generators can use + and/or modify the output of earlier generators.</para> + </listitem> + + <listitem> + <para>Generators are run by every manager instance, their output can be different for each + user.</para> + </listitem> + </itemizedlist> + + <para>It is recommended to use numerical prefixes for generator names to simplify ordering.</para> + </refsect1> + + <refsect1> + <title>Examples</title> + + <example> + <title>A simple generator that extends an environment variable if a directory exists in the file system</title> + + <programlisting># 50-xdg-data-dirs.sh + +<xi:include href="50-xdg-data-dirs.sh" parse="text" /></programlisting> + </example> + + <example> + <title>A more complicated generator which reads existing configuration and mutates one variable</title> + + <programlisting># 90-rearrange-path.py + +<xi:include href="90-rearrange-path.py" parse="text" /></programlisting> + </example> + + <example> + <title>Debugging a generator</title> + + <programlisting>SYSTEMD_LOG_LEVEL=debug VAR_A=something VAR_B="something else" \ +&systemenvgeneratordir;/path-to-generator +</programlisting> + </example> + </refsect1> + + <refsect1> + <title>See also</title> + + <para> + <citerefentry><refentrytitle>systemd-environment-d-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> + </para> + </refsect1> +</refentry> |