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authorLennart Poettering <lennart@poettering.net>2009-03-05 04:33:40 +0100
committerLennart Poettering <lennart@poettering.net>2009-03-05 04:33:40 +0100
commit3122008704ad07fe4982de0e642576ca7613d7bf (patch)
tree9b95a7dfd4d5e88f2a517ea66a66b5af78e45fe9 /src/pulse/fork-detect.c
parent9d29b96ac08c2762b27f6b191ec5807ee3ce58e7 (diff)
try to detect when stupid clients forks and refuse all service from then on
Diffstat (limited to 'src/pulse/fork-detect.c')
-rw-r--r--src/pulse/fork-detect.c59
1 files changed, 59 insertions, 0 deletions
diff --git a/src/pulse/fork-detect.c b/src/pulse/fork-detect.c
new file mode 100644
index 00000000..f10fc029
--- /dev/null
+++ b/src/pulse/fork-detect.c
@@ -0,0 +1,59 @@
+/***
+ 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, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ USA.
+***/
+
+#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(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;
+ }
+}