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authorUlrich Drepper <drepper@redhat.com>2003-05-17 20:49:02 +0000
committerUlrich Drepper <drepper@redhat.com>2003-05-17 20:49:02 +0000
commit68a396e83a8e1e50d0dfde8ffb090a8df311453f (patch)
tree1722f8620a6d09bfc480c749becee6b875959f2d /nptl/sem_close.c
parent2384fe204b6de4a45402b48af89b2f01bdb08e73 (diff)
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Fix one endless loop. Implement correct semantics wrt opening the same semaphore more then once.
Diffstat (limited to 'nptl/sem_close.c')
-rw-r--r--nptl/sem_close.c58
1 files changed, 55 insertions, 3 deletions
diff --git a/nptl/sem_close.c b/nptl/sem_close.c
index 379565f518..279522d086 100644
--- a/nptl/sem_close.c
+++ b/nptl/sem_close.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
@@ -17,13 +17,65 @@
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
-#include <semaphore.h>
+#include <errno.h>
+#include <search.h>
#include <sys/mman.h>
+#include "semaphoreP.h"
+
+
+/* Global variables to parametrize the walk function. This works
+ since we always have to use locks. And we have to use the twalk
+ function since the entries are not sorted wrt the mapping
+ address. */
+static sem_t *the_sem;
+static struct inuse_sem *rec;
+
+static void
+walker (const void *inodep, const VISIT which, const int depth)
+{
+ struct inuse_sem *nodep = *(struct inuse_sem **) inodep;
+
+ if (nodep->sem == the_sem)
+ rec = nodep;
+}
int
sem_close (sem)
sem_t *sem;
{
- return munmap (sem, sizeof (sem_t));
+ int result = 0;
+
+ /* Get the lock. */
+ lll_lock (__sem_mappings_lock);
+
+ /* Locate the entry for the mapping the caller provided. */
+ rec = NULL;
+ the_sem = sem;
+ twalk (__sem_mappings, walker);
+ if (rec != NULL)
+ {
+ /* Check the reference counter. If it is going to be zero, free
+ all the resources. */
+ if (--rec->refcnt == 0)
+ {
+ /* Remove the record from the tree. */
+ (void) tdelete (rec, &__sem_mappings, __sem_search);
+
+ result = munmap (rec->sem, sizeof (sem_t));
+
+ free (rec);
+ }
+ }
+ else
+ {
+ /* This is no valid semaphore. */
+ result = -1;
+ __set_errno (EINVAL);
+ }
+
+ /* Release the lock. */
+ lll_unlock (__sem_mappings_lock);
+
+ return result;
}