core: add basic infrastructure to record unit activation information

Not wired in by any unit type yet, just the basic to allocate,
ref, deref and plug in to other unit types.
Includes recording the trigger unit name and passing it to the
triggered unit as TRIGGER_UNIT= env var.

1 files changed, 22 insertions, 0 deletions

diff --git a/man/org.freedesktop.systemd1.xml b/man/org.freedesktop.systemd1.xml
index 120ffbc8ef..689ca3ec88 100644
--- a/man/org.freedesktop.systemd1.xml
+++ b/man/org.freedesktop.systemd1.xml
@@ -1898,6 +1898,7 @@ node /org/freedesktop/systemd1/unit/avahi_2ddaemon_2eservice {
       readonly s CollectMode = '...';
       @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
       readonly as Refs = ['...', ...];
+      readonly a(ss) ActivationDetails = [...];
   };
   interface org.freedesktop.DBus.Peer { ... };
   interface org.freedesktop.DBus.Introspectable { ... };
@@ -2229,6 +2230,8 @@ node /org/freedesktop/systemd1/unit/avahi_2ddaemon_2eservice {
 
     <variablelist class="dbus-property" generated="True" extra-ref="Refs"/>
 
+    <variablelist class="dbus-property" generated="True" extra-ref="ActivationDetails"/>
+
     <!--End of Autogenerated section-->
 
     <refsect2>
@@ -2406,6 +2409,18 @@ node /org/freedesktop/systemd1/unit/avahi_2ddaemon_2eservice {
 
       <para><varname>Transient</varname> contains a boolean that indicates whether the unit was created as a
       transient unit (i.e. via <function>CreateTransientUnit()</function> on the manager object).</para>
+
+      <para><varname>ActivationDetails</varname> contains a list of string pairs, key and value, that
+      describe the event that caused the unit to be activated, if any. The key describes the information
+      (e.g.: <varname>trigger_unit</varname>, with value <varname>foo.service</varname>). This is only filled
+      in if the unit was triggered by a <varname>Path</varname> or <varname>Timer</varname> unit, and it is
+      only provided in a best effort fashion: it is not guaranteed to be set, and it is not guaranteed to be
+      the only trigger. It is only guaranteed to be a valid trigger that caused the activation job to be
+      enqueued and complete successfully. The key value pairs correspond (in lowercase) to the environment
+      variables described in the <literal>Environment Variables Set on Triggered Units</literal> section in
+      <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+      Note that new key value pair may be added at any time in future versions. Existing entries will not be
+      removed.</para>
     </refsect2>
 
     <refsect2>
@@ -10650,6 +10665,8 @@ node /org/freedesktop/systemd1/job/666 {
       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
       readonly s JobType = '...';
       readonly s State = '...';
+      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
+      readonly a(ss) ActivationDetails = [...];
   };
   interface org.freedesktop.DBus.Peer { ... };
   interface org.freedesktop.DBus.Introspectable { ... };
@@ -10681,6 +10698,8 @@ node /org/freedesktop/systemd1/job/666 {
 
     <variablelist class="dbus-property" generated="True" extra-ref="State"/>
 
+    <variablelist class="dbus-property" generated="True" extra-ref="ActivationDetails"/>
+
     <!--End of Autogenerated section-->
 
     <refsect2>
@@ -10709,6 +10728,9 @@ node /org/freedesktop/systemd1/job/666 {
       <para><varname>State</varname> refers to the job's state and is one of <literal>waiting</literal> and
       <literal>running</literal>. The former indicates that a job is currently queued but has not begun to
       execute yet. The latter indicates that a job is currently being executed.</para>
+
+      <para><varname>ActivationDetails</varname> has the same content as the property of the same name under
+      the <varname>org.freedesktop.systemd1.Unit</varname> interface.</para>
     </refsect2>
   </refsect1>