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298 lines
16 KiB
298 lines
16 KiB
7 months ago
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From 2b5c9fceaaa30ec9c2d031c9ca32b71c43f22f98 Mon Sep 17 00:00:00 2001
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From: Lennart Poettering <lennart@poettering.net>
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Date: Tue, 3 Jan 2023 12:55:50 +0100
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Subject: [PATCH] notify: add --stopping + --reloading switches
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These wrap RELOADING=1 and STOPPING=1 messages. The former is
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particularly useful, since we want to insert the MONOTONIC_USEC= field
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into the message automatically, which is easy from C but harder from
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shell.
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(cherry picked from commit fd0f4da5457fbf7136f2d1888142d5fea75fd45a)
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Related: RHEL-6090
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---
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man/systemd-notify.xml | 107 ++++++++++++++++++++++++-----------------
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src/notify/notify.c | 39 +++++++++++++--
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2 files changed, 97 insertions(+), 49 deletions(-)
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diff --git a/man/systemd-notify.xml b/man/systemd-notify.xml
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index 1327d23155..a275123d40 100644
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--- a/man/systemd-notify.xml
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+++ b/man/systemd-notify.xml
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@@ -30,34 +30,35 @@
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<refsect1>
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<title>Description</title>
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- <para><command>systemd-notify</command> may be called by daemon
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- scripts to notify the init system about status changes. It can be
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- used to send arbitrary information, encoded in an
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- environment-block-like list of strings. Most importantly, it can be
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- used for start-up completion notification.</para>
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-
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- <para>This is mostly just a wrapper around
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- <function>sd_notify()</function> and makes this functionality
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+ <para><command>systemd-notify</command> may be called by service scripts to notify the invoking service
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+ manager about status changes. It can be used to send arbitrary information, encoded in an
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+ environment-block-like list of strings. Most importantly, it can be used for start-up completion
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+ notification.</para>
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+
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+ <para>This is mostly just a wrapper around <function>sd_notify()</function> and makes this functionality
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available to shell scripts. For details see
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<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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</para>
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- <para>The command line may carry a list of environment variables
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- to send as part of the status update.</para>
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+ <para>The command line may carry a list of environment variables to send as part of the status
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+ update.</para>
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<para>Note that systemd will refuse reception of status updates from this command unless
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<varname>NotifyAccess=</varname> is set for the service unit this command is called from.</para>
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- <para>Note that <function>sd_notify()</function> notifications may be attributed to units correctly only if either
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- the sending process is still around at the time PID 1 processes the message, or if the sending process is
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- explicitly runtime-tracked by the service manager. The latter is the case if the service manager originally forked
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- off the process, i.e. on all processes that match <varname>NotifyAccess=</varname><option>main</option> or
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- <varname>NotifyAccess=</varname><option>exec</option>. Conversely, if an auxiliary process of the unit sends an
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- <function>sd_notify()</function> message and immediately exits, the service manager might not be able to properly
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- attribute the message to the unit, and thus will ignore it, even if <varname>NotifyAccess=</varname><option>all
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- </option> is set for it. When <option>--no-block</option> is used, all synchronization for reception of notifications
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- is disabled, and hence the aforementioned race may occur if the invoking process is not the service manager or spawned
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- by the service manager.</para>
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+ <para>Note that <function>sd_notify()</function> notifications may be attributed to units correctly only
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+ if either the sending process is still around at the time the service manager processes the message, or
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+ if the sending process is explicitly runtime-tracked by the service manager. The latter is the case if
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+ the service manager originally forked off the process, i.e. on all processes that match
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+ <varname>NotifyAccess=</varname><option>main</option> or
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+ <varname>NotifyAccess=</varname><option>exec</option>. Conversely, if an auxiliary process of the unit
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+ sends an <function>sd_notify()</function> message and immediately exits, the service manager might not be
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+ able to properly attribute the message to the unit, and thus will ignore it, even if
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+ <varname>NotifyAccess=</varname><option>all</option> is set for it. To address this
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+ <command>systemd-notify</command> will wait until the notification message has been processed by the
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+ service manager. When <option>--no-block</option> is used, this synchronization for reception of
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+ notifications is disabled, and hence the aforementioned race may occur if the invoking process is not the
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+ service manager or spawned by the service manager.</para>
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<para>Hence, <command>systemd-notify</command> will first attempt to invoke <function>sd_notify()</function>
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pretending to have the PID of the invoking process. This will only succeed when invoked with sufficient privileges.
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@@ -66,7 +67,6 @@
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— appears as sender of the message, which in turn is helpful if the shell process is the main process of a service,
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due to the limitations of <varname>NotifyAccess=</varname><option>all</option>. Use the <option>--pid=</option>
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switch to tweak this behaviour.</para>
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-
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</refsect1>
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<refsect1>
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@@ -78,22 +78,42 @@
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<varlistentry>
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<term><option>--ready</option></term>
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- <listitem><para>Inform the init system about service start-up
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- completion. This is equivalent to <command>systemd-notify
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- READY=1</command>. For details about the semantics of this
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- option see
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+ <listitem><para>Inform the invoking service manager about service start-up or configuration reload
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+ completion. This is equivalent to <command>systemd-notify READY=1</command>. For details about the
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+ semantics of this option see
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+ <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
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+ </varlistentry>
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+
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+ <varlistentry>
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+ <term><option>--reloading</option></term>
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+
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+ <listitem><para>Inform the invoking service manager about the beginning of a configuration reload
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+ cycle. This is equivalent to <command>systemd-notify RELOADING=1</command> (but implicitly also sets
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+ a <varname>MONOTONIC_USEC=</varname> field as required for <varname>Type=notify-reload</varname>
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+ services, see
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+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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+ for details). For details about the semantics of this option see
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+ <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
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+ </varlistentry>
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+
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+ <varlistentry>
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+ <term><option>--stopping</option></term>
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+
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+ <listitem><para>Inform the invoking service manager about the beginning of the shutdown phase of the
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+ service. This is equivalent to <command>systemd-notify STOPPING=1</command>. For details about the
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+ semantics of this option see
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<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--pid=</option></term>
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- <listitem><para>Inform the service manager about the main PID of the daemon. Takes a PID as
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+ <listitem><para>Inform the service manager about the main PID of the service. Takes a PID as
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argument. If the argument is specified as <literal>auto</literal> or omitted, the PID of the process
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that invoked <command>systemd-notify</command> is used, except if that's the service manager. If the
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argument is specified as <literal>self</literal>, the PID of the <command>systemd-notify</command>
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command itself is used, and if <literal>parent</literal> is specified the calling process' PID is
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- used — even if it is the service manager. This is equivalent to <command>systemd-notify
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+ used — even if it is the service manager. The latter is equivalent to <command>systemd-notify
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MAINPID=$PID</command>. For details about the semantics of this option see
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<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
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</varlistentry>
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@@ -110,27 +130,26 @@
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<varlistentry>
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<term><option>--status=</option></term>
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- <listitem><para>Send a free-form status string for the daemon
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- to the init systemd. This option takes the status string as
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- argument. This is equivalent to <command>systemd-notify
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- STATUS=…</command>. For details about the semantics of this
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- option see
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- <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
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+ <listitem><para>Send a free-form human readable status string for the daemon to the service
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+ manager. This option takes the status string as argument. This is equivalent to
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+ <command>systemd-notify STATUS=…</command>. For details about the semantics of this option see
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+ <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>. This
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+ information is shown in
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+ <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
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+ <command>status</command> output, among other places.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--booted</option></term>
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- <listitem><para>Returns 0 if the system was booted up with
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- systemd, non-zero otherwise. If this option is passed, no
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- message is sent. This option is hence unrelated to the other
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- options. For details about the semantics of this option, see
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+ <listitem><para>Returns 0 if the system was booted up with systemd, non-zero otherwise. If this
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+ option is passed, no message is sent. This option is hence unrelated to the other options. For
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+ details about the semantics of this option, see
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<citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>. An
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alternate way to check for this state is to call
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- <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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- with the <command>is-system-running</command> command. It will
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- return <literal>offline</literal> if the system was not booted
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- with systemd. </para></listitem>
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+ <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> with
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+ the <command>is-system-running</command> command. It will return <literal>offline</literal> if the
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+ system was not booted with systemd. </para></listitem>
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</varlistentry>
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<varlistentry>
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@@ -162,9 +181,8 @@
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<example>
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<title>Start-up Notification and Status Updates</title>
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- <para>A simple shell daemon that sends start-up notifications
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- after having set up its communication channel. During runtime it
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- sends further status updates to the init system:</para>
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+ <para>A simple shell daemon that sends start-up notifications after having set up its communication
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+ channel. During runtime it sends further status updates to the init system:</para>
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<programlisting>#!/bin/sh
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@@ -192,5 +210,4 @@ done</programlisting>
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<citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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</para>
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</refsect1>
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-
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</refentry>
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diff --git a/src/notify/notify.c b/src/notify/notify.c
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index 7b23e7bdb0..2d4900a110 100644
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--- a/src/notify/notify.c
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+++ b/src/notify/notify.c
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@@ -23,6 +23,8 @@
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#include "util.h"
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static bool arg_ready = false;
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+static bool arg_reloading = false;
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+static bool arg_stopping = false;
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static pid_t arg_pid = 0;
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static const char *arg_status = NULL;
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static bool arg_booted = false;
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@@ -42,7 +44,10 @@ static int help(void) {
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"\n%sNotify the init system about service status updates.%s\n\n"
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" -h --help Show this help\n"
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" --version Show package version\n"
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- " --ready Inform the init system about service start-up completion\n"
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+ " --ready Inform the service manager about service start-up/reload\n"
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+ " completion\n"
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+ " --reloading Inform the service manager about configuration reloading\n"
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+ " --stopping Inform the service manager about service shutdown\n"
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" --pid[=PID] Set main PID of daemon\n"
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" --uid=USER Set user to send from\n"
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" --status=TEXT Set status text\n"
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@@ -81,6 +86,8 @@ static int parse_argv(int argc, char *argv[]) {
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enum {
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ARG_READY = 0x100,
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+ ARG_RELOADING,
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+ ARG_STOPPING,
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ARG_VERSION,
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ARG_PID,
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ARG_STATUS,
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@@ -93,6 +100,8 @@ static int parse_argv(int argc, char *argv[]) {
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{ "help", no_argument, NULL, 'h' },
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{ "version", no_argument, NULL, ARG_VERSION },
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{ "ready", no_argument, NULL, ARG_READY },
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+ { "reloading", no_argument, NULL, ARG_RELOADING },
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+ { "stopping", no_argument, NULL, ARG_STOPPING },
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{ "pid", optional_argument, NULL, ARG_PID },
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{ "status", required_argument, NULL, ARG_STATUS },
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{ "booted", no_argument, NULL, ARG_BOOTED },
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@@ -120,6 +129,14 @@ static int parse_argv(int argc, char *argv[]) {
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arg_ready = true;
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break;
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+ case ARG_RELOADING:
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+ arg_reloading = true;
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+ break;
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+
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+ case ARG_STOPPING:
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+ arg_stopping = true;
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+ break;
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+
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case ARG_PID:
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if (isempty(optarg) || streq(optarg, "auto")) {
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arg_pid = getppid();
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@@ -176,6 +193,8 @@ static int parse_argv(int argc, char *argv[]) {
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if (optind >= argc &&
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!arg_ready &&
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+ !arg_stopping &&
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+ !arg_reloading &&
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!arg_status &&
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!arg_pid &&
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!arg_booted) {
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@@ -187,10 +206,10 @@ static int parse_argv(int argc, char *argv[]) {
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}
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static int run(int argc, char* argv[]) {
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- _cleanup_free_ char *status = NULL, *cpid = NULL, *n = NULL;
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+ _cleanup_free_ char *status = NULL, *cpid = NULL, *n = NULL, *monotonic_usec = NULL;
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_cleanup_strv_free_ char **final_env = NULL;
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- char* our_env[4];
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- unsigned i = 0;
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+ char* our_env[7];
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+ size_t i = 0;
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pid_t source_pid;
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int r;
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@@ -212,9 +231,21 @@ static int run(int argc, char* argv[]) {
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return r <= 0;
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}
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+ if (arg_reloading) {
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+ our_env[i++] = (char*) "RELOADING=1";
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+
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+ if (asprintf(&monotonic_usec, "MONOTONIC_USEC=" USEC_FMT, now(CLOCK_MONOTONIC)) < 0)
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+ return log_oom();
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+
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+ our_env[i++] = monotonic_usec;
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+ }
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+
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if (arg_ready)
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our_env[i++] = (char*) "READY=1";
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+ if (arg_stopping)
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+ our_env[i++] = (char*) "STOPPING=1";
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+
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if (arg_status) {
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status = strjoin("STATUS=", arg_status);
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if (!status)
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