svn commit: r234057 - head/lib/libc/gen

[Jilles Tjoelker]

Author: jilles
Date: Mon Apr  9 14:17:22 2012
New Revision: 234057
URL: http://svn.freebsd.org/changeset/base/234057

Log:
  sem_open: Make sure to fail an O_CREAT|O_EXCL open, even if that semaphore
  is already open in this process.
  
  If the named semaphore is already open, sem_open() only increments a
  reference count and did not take the flags into account (which otherwise
  happens by passing them to open()). Add an extra check for O_CREAT|O_EXCL.
  
  PR:		kern/166706
  Reviewed by:	davidxu
  MFC after:	10 days

Modified:
  head/lib/libc/gen/sem_new.c

Modified: head/lib/libc/gen/sem_new.c
==============================================================================
--- head/lib/libc/gen/sem_new.c	Mon Apr  9 14:16:24 2012	(r234056)
+++ head/lib/libc/gen/sem_new.c	Mon Apr  9 14:17:22 2012	(r234057)
@@ -162,10 +162,16 @@ _sem_open(const char *name, int flags, .
 	_pthread_mutex_lock(&sem_llock);
 	LIST_FOREACH(ni, &sem_list, next) {
 		if (strcmp(name, ni->name) == 0) {
-			ni->open_count++;
-			sem = ni->sem;
-			_pthread_mutex_unlock(&sem_llock);
-			return (sem);
+			if ((flags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL)) {
+				_pthread_mutex_unlock(&sem_llock);
+				errno = EEXIST;
+				return (SEM_FAILED);
+			} else {
+				ni->open_count++;
+				sem = ni->sem;
+				_pthread_mutex_unlock(&sem_llock);
+				return (sem);
+			}
 		}
 	}