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< !DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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Copyright 2010 Lennart Poettering
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<refentry id= "sd_booted"
xmlns:xi="http://www.w3.org/2001/XInclude">
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<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>
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<refpurpose > Test whether the system is running the systemd init system</refpurpose>
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</refnamediv>
<refsynopsisdiv >
<funcsynopsis >
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<funcsynopsisinfo > #include < systemd/sd-daemon.h> </funcsynopsisinfo>
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<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
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with systemd as init system, this call returns a
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positive return value, zero otherwise.</para>
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</refsect1>
<refsect1 >
<title > Notes</title>
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<xi:include href= "libsystemd-pkgconfig.xml" xpointer= "pkgconfig-text" />
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<para > Internally, this function checks whether the
sd-booted: update sd_booted() check a bit
Previously we were testing whether /sys/fs/cgroup/systemd/ was a mount
point. This might be problematic however, when the cgroup trees are bind
mounted into a container from the host (which should be absolutely
valid), which might create the impression that the container was running
systemd, but only the host actually is.
Replace this by a check for the existance of the directory
/run/systemd/system/, which should work unconditionally, since /run can
never be a bind mount but *must* be a tmpfs on systemd systems, which is
flushed at boots. This means that data in /run always reflects
information about the current boot, and only of the local container,
which makes it the perfect choice for a check like this.
(As side effect this is nice to Ubuntu people who now use logind with
the systemd cgroup hierarchy, where the old sd_booted() check misdetects
systemd, even though they still run legacy Upstart.)
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directory <filename > /run/systemd/system/</filename>
exists. A simple check like this can also be
implemented trivially in shell or any other
language.</para>
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</refsect1>
<refsect1 >
<title > See Also</title>
<para >
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<citerefentry > <refentrytitle > systemd</refentrytitle> <manvolnum > 1</manvolnum> </citerefentry> ,
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<citerefentry > <refentrytitle > sd-daemon</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry>
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</para>
</refsect1>
</refentry>