notification.</para>
<para>If the <parameter>unset_environment</parameter>
- parameter is non-zero <function>sd_notify()</function>
+ parameter is non-zero, <function>sd_notify()</function>
will unset the <varname>$NOTIFY_SOCKET</varname>
- environment variable before returning (regardless
+ environment variable before returning (regardless of
whether the function call itself succeeded or
not). Further calls to
<function>sd_notify()</function> will then fail, but
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for details. It is recommended to send
this message if the
- <varname>WATCHDOG_USEC=</varname>
- environment variable has been set for
- the service process, in every half the
- time interval that is specified in the
- variable.</para></listitem>
+ <varname>$WATCHDOG_PID</varname>
+ environment variable has been set to
+ the PID of the service process, in
+ every half the time interval that is
+ specified in the
+ <varname>$WATCHDOG_USEC</varname>
+ environment variable. See
+ <citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ for details.</para></listitem>
</varlistentry>
</variablelist>
errno-style error code. If
<varname>$NOTIFY_SOCKET</varname> was not set and
hence no status data could be sent, 0 is returned. If
- the status was sent these functions return with a
+ the status was sent, these functions return with a
positive return value. In order to support both, init
systems that implement this scheme and those which
do not, it is generally recommended to ignore the return
<refsect1>
<title>Notes</title>
- <para>These functions are provided by the reference
- implementation of APIs for new-style daemons and
- distributed with the systemd package. The algorithms
- they implement are simple, and can easily be
- reimplemented in daemons if it is important to support
- this interface without using the reference
- implementation.</para>
+ <para>These APIs are implemented as a shared library,
+ which can be compiled and linked to with the
+ <constant>libsystemd</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ file.</para>
<para>Internally, these functions send a single
datagram with the state string as payload to the
<constant>AF_UNIX</constant> socket referenced in the
<varname>$NOTIFY_SOCKET</varname> environment
variable. If the first character of
- <varname>$NOTIFY_SOCKET</varname> is <literal>@</literal> the string is
+ <varname>$NOTIFY_SOCKET</varname> is <literal>@</literal>, the string is
understood as Linux abstract namespace socket. The
datagram is accompanied by the process credentials of
the sending daemon, using SCM_CREDENTIALS.</para>
-
- <para>For details about the algorithms check the
- liberally licensed reference implementation sources:
- <ulink url="http://cgit.freedesktop.org/systemd/systemd/plain/src/libsystemd-daemon/sd-daemon.c"/>
- and <ulink
- url="http://cgit.freedesktop.org/systemd/systemd/plain/src/systemd/sd-daemon.h"/></para>
-
- <para><function>sd_notify()</function> and
- <function>sd_notifyf()</function> are implemented in
- the reference implementation's
- <filename>sd-daemon.c</filename> and
- <filename>sd-daemon.h</filename> files. These
- interfaces are available as shared library, which can
- be compiled and linked to with the
- <constant>libsystemd-daemon</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- file. Alternatively, applications consuming these APIs
- may copy the implementation into their source tree. For
- more details about the reference implementation see
- <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
-
- <para>If the reference implementation is used as
- drop-in files and -DDISABLE_SYSTEMD is set during
- compilation these functions will always return 0 and
- otherwise become a NOP.</para>
</refsect1>
<refsect1>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff