Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ 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
- General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU General Public License
+ You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refnamediv>
<refname>daemon</refname>
- <refpurpose>Writing and Packaging System Daemons</refpurpose>
+ <refpurpose>Writing and packaging system daemons</refpurpose>
</refnamediv>
<refsect1>
<listitem><para>In the child, call
<function>fork()</function> again, to
- ensure the daemon can never re-aquire
+ ensure the daemon can never re-acquire
a terminal again.</para></listitem>
<listitem><para>Call <function>exit()</function> in the
<listitem><para>Instead of using the
<function>syslog()</function> call to log directly to the
- system logger, a new-style daemon may
+ system syslog service, a new-style daemon may
choose to simply log to STDERR via
<function>fprintf()</function>, which is then forwarded to
syslog by the init system. If log
<varname>StandardError=syslog</varname>
in the service unit file. For details
see
- <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>
and
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
url="http://refspecs.freestandards.org/LSB_3.1.1/LSB-Core-generic/LSB-Core-generic/iniscrptact.html">LSB
Linux Standard Base Core
Specification</ulink>. This method of
- activation is supported ubiquitiously on Linux
+ activation is supported ubiquitously on Linux
init systems, both old-style and new-style
systems. Among other issues SysV init scripts
have the disadvantage of involving shell
this scheme provided by systemd see
<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
and
- <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>. For
+ <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>. For
details about porting existing daemons to
socket-based activation see below. With
minimal effort it is possible to implement
to the CPU and IO schedulers. If a process
executed by the init system shall not
negatively impact the amount of CPU or IO
- bandwith available to other processes, it
+ bandwidth available to other processes, it
should be configured with
<varname>CPUSchedulingPolicy=idle</varname>
and/or
operating
system-independent.</para></listitem>
- <listitem><para>Since not all syslog
- implementations are socket-activatable
- yet, it is recommended to place an
- <varname>After=syslog.target</varname>
- dependency in service files for
- daemons that can log to
- syslog. <filename>syslog.target</filename>
- then either pulls in the syslog daemon
- itself or simply the activation
- socket. A <varname>Wants=</varname> or
- even <varname>Requires=</varname>
- dependency should generally not be
- added, since it should be up to the
- administrator whether he wants to
- enable logging or not, and most syslog
- clients work fine if no log daemon is
- running.</para></listitem>
-
<listitem><para>Make sure to include
an <literal>[Install]</literal>
section including installation
--variable=systemdsystemunitdir</command> (for
system services), resp. <command>pkg-config
systemd
- --variable=systemdsessionunitdir</command>
- (for session services). This will make the
+ --variable=systemduserunitdir</command>
+ (for user services). This will make the
services available in the system on explicit
request but not activate them automatically
during boot. Optionally, during package
AC_ARG_WITH([systemdsystemunitdir],
AS_HELP_STRING([--with-systemdsystemunitdir=DIR], [Directory for systemd service files]),
[], [with_systemdsystemunitdir=$($PKG_CONFIG --variable=systemdsystemunitdir systemd)])
-AC_SUBST([systemdsystemunitdir], [$with_systemdsystemunitdir])
-AM_CONDITIONAL(HAVE_SYSTEMD, [test -n "$with_systemdsystemunitdir"])</programlisting>
+if test "x$with_systemdsystemunitdir" != xno; then
+ AC_SUBST([systemdsystemunitdir], [$with_systemdsystemunitdir])
+fi
+AM_CONDITIONAL(HAVE_SYSTEMD, [test -n "$with_systemdsystemunitdir" -a "x$with_systemdsystemunitdir" != xno ])</programlisting>
<para>This snippet allows automatic
installation of the unit files on systemd
machines, and optionally allows their
installation even on machines lacking
systemd. (Modification of this snippet for the
- session unit directory is left as excercise to the
+ user unit directory is left as an exercise for the
reader.)</para>
<para>Additionally, to ensure that
<para>In the
<citerefentry><refentrytitle>rpm</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- <filename>.spec</filename> file use a snippet like
- the following to enable/disable the service
- during installation/deinstallation. Consult
+ <filename>.spec</filename> file use snippets
+ like the following to enable/disable the
+ service during
+ installation/deinstallation. This makes use of
+ the RPM macros shipped along systemd. Consult
the packaging guidelines of your distribution
for details and the equivalent for other
- package managers:</para>
+ package managers.</para>
- <programlisting>%post
-if [ $1 -eq 1 ]; then
- # Enable (but don't start) the units by default
- /bin/systemctl enable foobar.service foobar.socket >/dev/null 2>&1 || :
+ <para>At the top of the file:</para>
- # Alternatively, just call /bin/systemctl daemon-reload here,
- # if the daemon should not be enabled by default on package
- # installation
-fi
+ <programlisting>BuildRequires: systemd
+%{?systemd_requires}</programlisting>
+
+ <para>And as scriptlets, further down:</para>
+
+ <programlisting>%post
+%systemd_post foobar.service foobar.socket
%preun
-if [ $1 -eq 0 ]; then
- # Disable and stop the units
- /bin/systemctl disable foobar.service foobar.socket >/dev/null 2>&1 || :
- /bin/systemctl stop foobar.service foobar.socket >/dev/null 2>&1 || :
-fi
+%systemd_preun foobar.service foobar.socket
%postun
-if [ $1 -ge 1 ] ; then
- # On upgrade, reload init system configuration if we changed unit files
- /bin/systemctl daemon-reload >/dev/null 2>&1 || :
- # On upgrade, restart the daemon
- /bin/systemctl try-restart foobar.service >/dev/null 2>&1 || :
-fi</programlisting>
-
- <para>Depending on whether your service should
- or should not be started/stopped/restarted
- during package installation, deinstallation or
- upgrade, a different set of commands may be
- specified. See
- <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- for details.</para>
+%systemd_postun</programlisting>
+
+ <para>If the service shall be restarted during
+ upgrades replace the
+ <literal>%postun</literal> scriptlet above
+ with the following:</para>
+
+ <programlisting>%postun
+%systemd_postun_with_restart foobar.service</programlisting>
+
+ <para>Note that
+ <literal>%systemd_post</literal> and
+ <literal>%systemd_preun</literal> expect the
+ names of all units that are installed/removed
+ as arguments, separated by
+ spaces. <literal>%systemd_postun</literal>
+ expects no
+ arguments. <literal>%systemd_postun_with_restart</literal>
+ expects the units to restart as
+ arguments.</para>
<para>To facilitate upgrades from a package
version that shipped only SysV init scripts to
script and a native systemd service file, use
a fragment like the following:</para>
- <programlisting>%triggerin -- foobar < 0.47.11-1
-if /sbin/chkconfig foobar ; then
- /bin/systemctl enable foobar.service foobar.socket >/dev/null 2>&1 || :
+ <programlisting>%triggerun -- foobar < 0.47.11-1
+if /sbin/chkconfig --level 5 foobar ; then
+ /bin/systemctl --no-reload enable foobar.service foobar.socket >/dev/null 2>&1 || :
fi</programlisting>
<para>Where 0.47.11-1 is the first package
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
~ianmdlvl / elogind.git / blobdiff