[PATCH alsa-utils 1/2] alsactl: Fix double decrease of lock timeout
The state_lock() has a loop to wait for the lock file creation, and the timeout value gets decremented twice mistakenly, which leads to a half timeout (5 seconds) than expected 10 seconds. Fix it.
Signed-off-by: Takashi Iwai tiwai@suse.de --- alsactl/lock.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/alsactl/lock.c b/alsactl/lock.c index 4a485392b3bd..05f6e4d2a102 100644 --- a/alsactl/lock.c +++ b/alsactl/lock.c @@ -63,7 +63,6 @@ static int state_lock_(const char *file, int lock, int timeout, int _fd) if (fd < 0) { if (errno == EBUSY || errno == EAGAIN) { sleep(1); - timeout--; } else { err = -errno; goto out;
A race at creating a lock file in state_lock() was discovered recently: namely, between the first open(O_RDWR) and the second open(O_RDWR|O_CREAT|O_EXCL) calls, another alsactl invocation may already create a lock file, then the second open() will return EEXIST, which isn't handled properly and treated as a fatal error.
In this patch, we check EEXIST case and try again open() with O_RDWR. This must succeed usually, and if it fails, handle finally as the fatal error.
BugLink: https://bugzilla.opensuse.org/show_bug.cgi?id=1179904 Signed-off-by: Takashi Iwai tiwai@suse.de --- alsactl/lock.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/alsactl/lock.c b/alsactl/lock.c index 05f6e4d2a102..5b4746231996 100644 --- a/alsactl/lock.c +++ b/alsactl/lock.c @@ -63,10 +63,15 @@ static int state_lock_(const char *file, int lock, int timeout, int _fd) if (fd < 0) { if (errno == EBUSY || errno == EAGAIN) { sleep(1); - } else { - err = -errno; - goto out; + continue; } + if (errno == EEXIST) { + fd = open(nfile, O_RDWR); + if (fd >= 0) + break; + } + err = -errno; + goto out; } } }
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Takashi Iwai