set exit_idle_time to 0 when we detect a session

As the comments explain, this fixes relogin problems on some systems
that remove our sockets on logout without terminating the daemon.

man/pulse-daemon.conf.5.xml.in

@@ -292,9 +292,18 @@ License along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
     <option>
       <p><opt>exit-idle-time=</opt> Terminate the daemon after the
       last client quit and this time in seconds passed. Use a negative value to
-      disable this feature. Defaults to 20. The
-      <opt>--exit-idle-time</opt> command line option takes
-      precedence.</p>
+      disable this feature. Defaults to 20. The <opt>--exit-idle-time</opt>
+      command line option takes precedence.</p>
+
+      <p>When PulseAudio runs in the per-user mode and detects a login
+      session, then any positive value will be reset to 0 so that PulseAudio
+      will terminate immediately on logout. A positive value therefore has
+      effect only in environments where there's no support for login session
+      tracking. A negative value can still be used to disable any automatic
+      exit.</p>
+
+      <p>When PulseAudio runs in the system mode, automatic exit is always
+      disabled, so this option does nothing.</p>
     </option>
 
     <option>

man/pulseaudio.1.xml.in

@@ -189,8 +189,21 @@ License along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
     <option>
       <p><opt>--exit-idle-time</opt><arg>=SECS</arg></p>
 
-      <optdesc><p>Terminate the daemon when idle and the specified
-      number of seconds passed.</p></optdesc>
+      <optdesc>
+        <p>Terminate the daemon after the last client quit and this time in
+        seconds passed. Use a negative value to disable this feature. Defaults
+        to 20.</p>
+
+        <p>When PulseAudio runs in the per-user mode and detects a login
+        session, then any positive value will be reset to 0 so that PulseAudio
+        will terminate immediately on logout. A positive value therefore has
+        effect only in environments where there's no support for login session
+        tracking. A negative value can still be used to disable any automatic
+        exit.</p>
+
+        <p>When PulseAudio runs in the system mode, automatic exit is always
+        disabled, so this option does nothing.</p>
+      </optdesc>
     </option>
 
     <option>

src/modules/module-console-kit.c

@@ -118,6 +118,19 @@ static void add_session(struct userdata *u, const char *id) {
 
     pa_log_debug("Added new session %s", id);
 
+    /* Positive exit_idle_time is only useful when we have no session tracking
+     * capability, so we can set it to 0 now that we have detected a session.
+     * The benefit of setting exit_idle_time to 0 is that pulseaudio will exit
+     * immediately when the session ends. That in turn is useful, because some
+     * systems (those that use pam_systemd but don't use systemd for managing
+     * pulseaudio) clean $XDG_RUNTIME_DIR on logout, but fail to terminate all
+     * services that depend on the files in $XDG_RUNTIME_DIR. The directory
+     * contains our sockets, and if the sockets are removed without terminating
+     * pulseaudio, a quick relogin will likely cause trouble, because a new
+     * instance will be spawned while the old instance is still running. */
+    if (u->core->exit_idle_time > 0)
+        pa_core_set_exit_idle_time(u->core, 0);
+
 fail:
 
     if (m)

src/modules/module-systemd-login.c

@@ -84,6 +84,20 @@ static int add_session(struct userdata *u, const char *id) {
     pa_hashmap_put(u->sessions, session->id, session);
 
     pa_log_debug("Added new session %s", id);
+
+    /* Positive exit_idle_time is only useful when we have no session tracking
+     * capability, so we can set it to 0 now that we have detected a session.
+     * The benefit of setting exit_idle_time to 0 is that pulseaudio will exit
+     * immediately when the session ends. That in turn is useful, because some
+     * systems (those that use pam_systemd but don't use systemd for managing
+     * pulseaudio) clean $XDG_RUNTIME_DIR on logout, but fail to terminate all
+     * services that depend on the files in $XDG_RUNTIME_DIR. The directory
+     * contains our sockets, and if the sockets are removed without terminating
+     * pulseaudio, a quick relogin will likely cause trouble, because a new
+     * instance will be spawned while the old instance is still running. */
+    if (u->core->exit_idle_time > 0)
+        pa_core_set_exit_idle_time(u->core, 0);
+
     return 0;
 }
 

src/modules/x11/module-x11-xsmp.c

@@ -206,6 +206,19 @@ int pa__init(pa_module*m) {
     if (!u->client)
         goto fail;
 
+    /* Positive exit_idle_time is only useful when we have no session tracking
+     * capability, so we can set it to 0 now that we have detected a session.
+     * The benefit of setting exit_idle_time to 0 is that pulseaudio will exit
+     * immediately when the session ends. That in turn is useful, because some
+     * systems (those that use pam_systemd but don't use systemd for managing
+     * pulseaudio) clean $XDG_RUNTIME_DIR on logout, but fail to terminate all
+     * services that depend on the files in $XDG_RUNTIME_DIR. The directory
+     * contains our sockets, and if the sockets are removed without terminating
+     * pulseaudio, a quick relogin will likely cause trouble, because a new
+     * instance will be spawned while the old instance is still running. */
+    if (u->core->exit_idle_time > 0)
+        pa_core_set_exit_idle_time(u->core, 0);
+
     pa_modargs_free(ma);
 
     return 0;

src/pulsecore/core.c

@@ -426,6 +426,16 @@ void pa_core_update_default_source(pa_core *core) {
     pa_hook_fire(&core->hooks[PA_CORE_HOOK_DEFAULT_SOURCE_CHANGED], core->default_source);
 }
 
+void pa_core_set_exit_idle_time(pa_core *core, int time) {
+    pa_assert(core);
+
+    if (time == core->exit_idle_time)
+        return;
+
+    pa_log_info("exit_idle_time: %i -> %i", core->exit_idle_time, time);
+    core->exit_idle_time = time;
+}
+
 static void exit_callback(pa_mainloop_api *m, pa_time_event *e, const struct timeval *t, void *userdata) {
     pa_core *c = userdata;
     pa_assert(c->exit_event == e);

src/pulsecore/core.h

@@ -258,6 +258,8 @@ void pa_core_set_configured_default_source(pa_core *core, const char *source);
 void pa_core_update_default_sink(pa_core *core);
 void pa_core_update_default_source(pa_core *core);
 
+void pa_core_set_exit_idle_time(pa_core *core, int time);
+
 /* Check whether no one is connected to this core */
 void pa_core_check_idle(pa_core *c);