From ac0f5275c5cbe72d5c81d9bb4aed4b9c2a5f5802 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 11 Jun 2008 17:38:50 +0000
Subject: add new switch --start to the PA binary which allows starting PA if
 it is not running yet. In contrast to normal startup an already running PA
 will not be considered an error. Also, take the autospawn lock so we can
 guarantee that after this call returns PA is ralive and running

git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@2513 fefdeb5f-60dc-0310-8127-8f9354f1896f
---
 src/daemon/main.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 50 insertions(+), 6 deletions(-)

(limited to 'src/daemon/main.c')

diff --git a/src/daemon/main.c b/src/daemon/main.c
index 6e5997cf..d4c16fef 100644
--- a/src/daemon/main.c
+++ b/src/daemon/main.c
@@ -96,6 +96,8 @@
 #include "ltdl-bind-now.h"
 #include "polkit.h"
 
+#define AUTOSPAWN_LOCK "autospawn.lock"
+
 #ifdef HAVE_LIBWRAP
 /* Only one instance of these variables */
 int allow_severity = LOG_INFO;
@@ -344,6 +346,8 @@ int main(int argc, char *argv[]) {
     pa_time_event *win32_timer;
     struct timeval win32_tv;
 #endif
+    char *lf = NULL;
+    int autospawn_lock_fd = -1;
 
 #if defined(__linux__) && defined(__OPTIMIZE__)
     /*
@@ -486,13 +490,13 @@ int main(int argc, char *argv[]) {
     if (conf->high_priority && !pa_can_high_priority())
         pa_log_warn("High-priority scheduling enabled in configuration but not allowed by policy.");
 
-    if (conf->high_priority && conf->cmd == PA_CMD_DAEMON)
+    if (conf->high_priority && (conf->cmd == PA_CMD_DAEMON || conf->cmd == PA_CMD_START))
         pa_raise_priority(conf->nice_level);
 
     if (suid_root) {
         pa_bool_t drop;
 
-        drop = conf->cmd != PA_CMD_DAEMON || !conf->realtime_scheduling;
+        drop = (conf->cmd != PA_CMD_DAEMON && conf->cmd != PA_CMD_START) || !conf->realtime_scheduling;
 
 #ifdef RLIMIT_RTPRIO
         if (!drop) {
@@ -608,7 +612,7 @@ int main(int argc, char *argv[]) {
             goto finish;
 
         default:
-            pa_assert(conf->cmd == PA_CMD_DAEMON);
+            pa_assert(conf->cmd == PA_CMD_DAEMON || conf->cmd == PA_CMD_START);
     }
 
     if (real_root && !conf->system_instance)
@@ -618,6 +622,15 @@ int main(int argc, char *argv[]) {
         goto finish;
     }
 
+    if (conf->cmd == PA_CMD_START) {
+        /* If we shall start PA only when it is not running yet, we
+         * first take the autospawn lock to make things
+         * synchronous. */
+
+        lf = pa_runtime_path(AUTOSPAWN_LOCK);
+        autospawn_lock_fd = pa_lock_lockfile(lf);
+    }
+
     if (conf->daemonize) {
         pid_t child;
         int tty_fd;
@@ -661,6 +674,14 @@ int main(int argc, char *argv[]) {
             goto finish;
         }
 
+        if (autospawn_lock_fd >= 0) {
+            /* The lock file is unlocked from the parent, so we need
+             * to close it in the child */
+
+            pa_close(autospawn_lock_fd);
+            autospawn_lock_fd = -1;
+        }
+
         pa_assert_se(pa_close(daemon_pipe[0]) == 0);
         daemon_pipe[0] = -1;
 #endif
@@ -728,7 +749,20 @@ int main(int argc, char *argv[]) {
     pa_log_info("Running in system mode: %s", pa_yes_no(pa_in_system_mode()));
 
     if (conf->use_pid_file) {
-        if (pa_pid_file_create("pulseaudio") < 0) {
+        int z;
+
+        if ((z = pa_pid_file_create("pulseaudio")) != 0) {
+
+            if (conf->cmd == PA_CMD_START && z > 0) {
+                /* If we are already running and with are run in
+                 * --start mode, then let's return this as success. */
+
+                pa_log_info("z=%i rock!", z);
+
+                retval = 0;
+                goto finish;
+            }
+
             pa_log("pa_pid_file_create() failed.");
             goto finish;
         }
@@ -826,11 +860,12 @@ int main(int argc, char *argv[]) {
         goto finish;
     }
 
-
 #ifdef HAVE_FORK
-    if (conf->daemonize) {
+    if (daemon_pipe[1] >= 0) {
         int ok = 0;
         pa_loop_write(daemon_pipe[1], &ok, sizeof(ok), NULL);
+        pa_close(daemon_pipe[1]);
+        daemon_pipe[1] = -1;
     }
 #endif
 
@@ -844,6 +879,12 @@ int main(int argc, char *argv[]) {
 
 finish:
 
+    if (autospawn_lock_fd >= 0)
+        pa_unlock_lockfile(lf, autospawn_lock_fd);
+
+    if (lf)
+        pa_xfree(lf);
+
 #ifdef OS_IS_WIN32
     if (win32_timer)
         pa_mainloop_get_api(mainloop)->time_free(win32_timer);
@@ -860,6 +901,9 @@ finish:
     pa_signal_done();
 
 #ifdef HAVE_FORK
+    if (daemon_pipe[1] >= 0)
+        pa_loop_write(daemon_pipe[1], &retval, sizeof(retval), NULL);
+
     pa_close_pipe(daemon_pipe);
 #endif
 
-- 
cgit