1 files changed, 57 insertions, 0 deletions
diff --git a/src/pulse/fork-detect.c b/src/pulse/fork-detect.c
new file mode 100644
index 0000000..9299304
--- /dev/null
+++ b/src/pulse/fork-detect.c
@@ -0,0 +1,57 @@
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2009 Lennart Poettering
+
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as published
+  by the Free Software Foundation; either version 2.1 of the License,
+  or (at your option) any later version.
+
+  PulseAudio is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <unistd.h>
+
+#include <pulsecore/atomic.h>
+#include <pulsecore/macro.h>
+
+#include "fork-detect.h"
+
+int pa_detect_fork(void) {
+    static pa_atomic_t pid = PA_ATOMIC_INIT((int) -1);
+
+    /* Some really stupid applications (Hey, vim, that means you!)
+     * love to fork after initializing
+     * gtk/libcanberra/pulseaudio. This is really bad style. We
+     * however have to deal with this cleanly, so we try to detect the
+     * forks making sure all our calls fail cleanly after the fork. */
+
+    pa_assert_cc(sizeof(pa_atomic_t) >= sizeof(pid_t));
+
+    for (;;) {
+        pid_t stored_pid = (pid_t) pa_atomic_load(&pid);
+
+        /* First let's check whether the current pid matches the stored one */
+        if (stored_pid == getpid())
+            return false;
+
+        /* Does it contain a different PID than ours? Then the process got forked. */
+        if ((int) stored_pid != (int) -1)
+            return true;
+
+        /* Ok, it still contains no PID, then store it */
+        if (pa_atomic_cmpxchg(&pid, (int) -1, (int) getpid()))
+            return false;
+    }
+}