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authorRich Felker <dalias@aerifal.cx>2011-03-10 21:52:18 -0500
committerRich Felker <dalias@aerifal.cx>2011-03-10 21:52:18 -0500
commitcfe581b6bc795e3f00ac30791314ec0f9be4b4ad (patch)
treea9167b25647df5508a64e3b0b79b7582714c8e2e
parent81af503610761a69476a3adbe8341fa8b6d078aa (diff)
downloadmusl-cfe581b6bc795e3f00ac30791314ec0f9be4b4ad.tar.gz
fix some semaphore wait semantics (race condition deadlock and error checking)
-rw-r--r--src/thread/sem_timedwait.c5
-rw-r--r--src/thread/sem_trywait.c3
2 files changed, 7 insertions, 1 deletions
diff --git a/src/thread/sem_timedwait.c b/src/thread/sem_timedwait.c
index e6c2495a..ad3bf075 100644
--- a/src/thread/sem_timedwait.c
+++ b/src/thread/sem_timedwait.c
@@ -8,7 +8,12 @@ int sem_timedwait(sem_t *sem, const struct timespec *at)
for (;;) {
if (a_fetch_add(sem->__val, -1) > 0) return 0;
val = a_fetch_add(sem->__val, 1)+1;
+ if (val==1) __wake(sem->__val, 1, 0);
CANCELPT_BEGIN;
+ if (at && at->tv_nsec >= 1000000000UL) {
+ errno = EINVAL;
+ return -1;
+ }
if (val <= 0 && __timedwait(sem->__val, val, CLOCK_REALTIME, at, 0) == ETIMEDOUT) {
errno = ETIMEDOUT;
return -1;
diff --git a/src/thread/sem_trywait.c b/src/thread/sem_trywait.c
index d0e928ef..c5370c70 100644
--- a/src/thread/sem_trywait.c
+++ b/src/thread/sem_trywait.c
@@ -5,7 +5,8 @@ int sem_trywait(sem_t *sem)
{
int val = a_fetch_add(sem->__val, -1);
if (val > 0) return 0;
- a_inc(sem->__val);
+ if (!a_fetch_add(sem->__val, 1))
+ __wake(sem->__val, 1, 0);
errno = EAGAIN;
return -1;
}