auto import from //branches/cupcake/...@127101
diff --git a/libc/bionic/semaphore.c b/libc/bionic/semaphore.c
index fa9de0e..0c94600 100644
--- a/libc/bionic/semaphore.c
+++ b/libc/bionic/semaphore.c
@@ -29,6 +29,7 @@
#include <errno.h>
#include <sys/time.h>
#include <sys/atomics.h>
+#include <time.h>
int sem_init(sem_t *sem, int pshared, unsigned int value)
{
@@ -118,6 +119,62 @@
return 0;
}
+int sem_timedwait(sem_t *sem, const struct timespec *abs_timeout)
+{
+ int ret;
+
+ if (sem == NULL) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ /* POSIX says we need to try to decrement the semaphore
+ * before checking the timeout value */
+ if (__atomic_dec_if_positive(&sem->count))
+ return 0;
+
+ /* check it as per Posix */
+ if (abs_timeout == NULL ||
+ abs_timeout->tv_sec < 0 ||
+ abs_timeout->tv_nsec < 0 ||
+ abs_timeout->tv_nsec >= 1000000000)
+ {
+ errno = EINVAL;
+ return -1;
+ }
+
+ for (;;) {
+ struct timespec ts;
+ int ret;
+
+ /* Posix mandates CLOCK_REALTIME here */
+ clock_gettime( CLOCK_REALTIME, &ts );
+ ts.tv_sec = abs_timeout->tv_sec - ts.tv_sec;
+ ts.tv_nsec = abs_timeout->tv_nsec - ts.tv_nsec;
+ if (ts.tv_nsec < 0) {
+ ts.tv_nsec += 1000000000;
+ ts.tv_sec -= 1;
+ }
+
+ if (ts.tv_sec < 0 || ts.tv_nsec < 0) {
+ errno = ETIMEDOUT;
+ return -1;
+ }
+
+ ret = __futex_wait(&sem->count, 0, &ts);
+
+ /* return in case of timeout or interrupt */
+ if (ret == -ETIMEDOUT || ret == -EINTR) {
+ errno = -ret;
+ return -1;
+ }
+
+ if (__atomic_dec_if_positive(&sem->count))
+ break;
+ }
+ return 0;
+}
+
int sem_post(sem_t *sem)
{
if (sem == NULL)