From f8f3e115d3c8253de677f6e7c78831b8ec18fab2 Mon Sep 17 00:00:00 2001
From: deischen <deischen@FreeBSD.org>
Date: Fri, 6 Feb 2004 13:54:38 +0000
Subject: Only allow the semaphore to be taken when the value is positive.
 Don't decrement it twice when it is taken.

Reported by:	kris
---
 lib/libc/gen/sem.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

(limited to 'lib')

diff --git a/lib/libc/gen/sem.c b/lib/libc/gen/sem.c
index 34ea8f7..ec80bc3 100644
--- a/lib/libc/gen/sem.c
+++ b/lib/libc/gen/sem.c
@@ -304,14 +304,13 @@ __sem_trywait(sem_t *sem)
  		retval = ksem_trywait((*sem)->semid);
 	else {
 		_pthread_mutex_lock(&(*sem)->lock);
-		if ((*sem)->count != 0) {
+		if ((*sem)->count > 0) {
 			(*sem)->count--;
 			retval = 0;
 		} else {
 			errno = EAGAIN;
 			retval = -1;
 		}
-		(*sem)->count--;
 		_pthread_mutex_unlock(&(*sem)->lock);
 	}
 	return (retval);
-- 
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