fix bug whereby sem_open leaked its own internal slots on failure

diff --git a/src/thread/sem_open.c b/src/thread/sem_open.c
index 8a72d4c62a317314e077716c7569306a349a90c8..66f12ee42000450e5b26ef56b51f11b61ad835ab 100644 (file)
--- a/src/thread/sem_open.c
+++ b/src/thread/sem_open.c
@@ -67,15 +67,15 @@ sem_t *sem_open(const char *name, int flags, ...)
 
        flags &= (O_CREAT|O_EXCL);
 
+       pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+
        /* Early failure check for exclusive open; otherwise the case
         * where the semaphore already exists is expensive. */
        if (flags == (O_CREAT|O_EXCL) && access(name, F_OK) == 0) {
                errno = EEXIST;
-               return SEM_FAILED;
+               goto fail;
        }
 
-       pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
-
        for (;;) {
                /* If exclusive mode is not requested, try opening an
                 * existing file first and fall back to creation. */
@@ -153,6 +153,9 @@ sem_t *sem_open(const char *name, int flags, ...)
 
 fail:
        pthread_setcancelstate(cs, 0);
+       LOCK(lock);
+       semtab[slot].sem = 0;
+       UNLOCK(lock);
        return SEM_FAILED;
 }