<?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"> <!-- This file is part of systemd. 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 (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. You should have received a copy of the GNU General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. --> <refentry id="sd_booted"> <refentryinfo> <title>sd_booted</title> <productname>systemd</productname> <authorgroup> <author> <contrib>Developer</contrib> <firstname>Lennart</firstname> <surname>Poettering</surname> <email>lennart@poettering.net</email> </author> </authorgroup> </refentryinfo> <refmeta> <refentrytitle>sd_booted</refentrytitle> <manvolnum>3</manvolnum> </refmeta> <refnamediv> <refname>sd_booted</refname> <refpurpose>Test whether the system is running the systemd init system.</refpurpose> </refnamediv> <refsynopsisdiv> <funcsynopsis> <funcsynopsisinfo>#include "sd-daemon.h"</funcsynopsisinfo> <funcprototype> <funcdef>int <function>sd_booted</function></funcdef> <paramdef>void</paramdef> </funcprototype> </funcsynopsis> </refsynopsisdiv> <refsect1> <title>Description</title> <para><function>sd_booted()</function> checks whether the system was booted up using the systemd init system.</para> </refsect1> <refsect1> <title>Return Value</title> <para>On failure, this call returns a negative errno-style error code. If the system was booted up with systemd as init system, this call returns a positive return value, zero otherwise.</para> </refsect1> <refsect1> <title>Notes</title> <para>This function is provided by the reference implementation of APIs for new-style daemons and distributed with the systemd package. The algorithm it implements is simple, and can easily be reimplemented in daemons if it is important to support this interface without using the reference implementation.</para> <para>Internally, this function checks whether the <filename>/sys/fs/cgroup/systemd</filename> virtual file system is mounted, by comparing the st_dev value of the <function>stat()</function> data of <filename>/sys/fs/cgroup</filename> and <filename>/sys/fs/cgroup/systemd</filename>.</para> <para>For details about the algorithm check the liberally licensed reference implementation sources: <ulink url="http://cgit.freedesktop.org/systemd/tree/src/sd-daemon.c"/> resp. <ulink url="http://cgit.freedesktop.org/systemd/tree/src/sd-daemon.h"/></para> <para><function>sd_booted()</function> is implemented in the reference implementation's drop-in <filename>sd-daemon.c</filename> and <filename>sd-daemon.h</filename> files. It is recommended that applications consuming these APIs copy the implementation into their source tree. For more details about the reference implementation see <citerefentry><refentrytitle>sd_daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry></para> <para>If -DDISABLE_SYSTEMD is set during compilation this function will always return 0 and otherwise become a NOP.</para> </refsect1> <refsect1> <title>See Also</title> <para> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>sd_daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry> </para> </refsect1> </refentry>