notify: document that we fake the PID when sending sd_notify()

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Lennart Poettering 2017-02-06 20:01:24 +01:00
parent b3bb64767a
commit aa20394579
1 changed files with 7 additions and 0 deletions

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@ -83,6 +83,13 @@
<function>sd_notify()</function> message and immediately exits, the service manager might not be able to properly
attribute the message to the unit, and thus will ignore it, even if
<varname>NotifyAccess=</varname><option>all</option> is set for it.</para>
<para><command>systemd-notify</command> will first attempt to invoke <function>sd_notify()</function> pretending to
have the PID of the invoking process. This will only succeed when invoked with sufficient privileges. On failure,
it will then fall back to invoking it under its own PID. This behaviour is useful in order that when the tool is
invoked from a shell script the shell process — and not the <command>systemd-notify</command> process — appears as
sender of the message, which in turn is helpful if the shell process is the main process of a service, due to the
limitations of <varname>NotifyAccess=</varname><option>all</option> described above.</para>
</refsect1>
<refsect1>