From: Julian Seward <jseward@acm.org>
Date: Sun, 2 Sep 2012 20:58:17 +0000 (+0000)
Subject: Merge from trunk, revs 12897 and 12898.  (Handle non-zero sem_*wait()
X-Git-Tag: svn/VALGRIND_3_8_1~12
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0aa57eef725fd6a1ea3e96ae15a40511e8346f49;p=thirdparty%2Fvalgrind.git

Merge from trunk, revs 12897 and 12898.  (Handle non-zero sem_*wait()
return values correctly, #305690)



git-svn-id: svn://svn.valgrind.org/valgrind/branches/VALGRIND_3_8_BRANCH@12945
---

diff --git a/drd/drd_semaphore.c b/drd/drd_semaphore.c
index 5045805464..226c5ea80f 100644
--- a/drd/drd_semaphore.c
+++ b/drd/drd_semaphore.c
@@ -339,8 +339,7 @@ void DRD_(semaphore_pre_wait)(const Addr semaphore)
 
 /**
  * Called after sem_wait() finished.
- * @note Do not rely on the value of 'waited' -- some glibc versions do
- *       not set it correctly.
+ * @note Some C libraries do not set the 'waited' value correctly.
  */
 void DRD_(semaphore_post_wait)(const DrdThreadId tid, const Addr semaphore,
                                const Bool waited)
@@ -348,16 +347,17 @@ void DRD_(semaphore_post_wait)(const DrdThreadId tid, const Addr semaphore,
    struct semaphore_info* p;
    Segment* sg;
 
+   tl_assert(waited == 0 || waited == 1);
    p = semaphore_get(semaphore);
    if (s_trace_semaphore)
-      DRD_(trace_msg)("[%d] sem_wait      0x%lx value %u -> %u",
+      DRD_(trace_msg)("[%d] sem_wait      0x%lx value %u -> %u%s",
                       DRD_(thread_get_running_tid)(), semaphore,
-                      p ? p->value : 0, p ? p->value - 1 : 0);
+                      p ? p->value : 0, p ? p->value - waited : 0,
+		      waited ? "" : " (did not wait)");
 
-   if (p)
-   {
+   if (p) {
       p->waiters--;
-      p->value--;
+      p->value -= waited;
    }
 
    /*
@@ -378,6 +378,9 @@ void DRD_(semaphore_post_wait)(const DrdThreadId tid, const Addr semaphore,
       return;
    }
 
+   if (!waited)
+      return;
+
    if (p->waits_to_skip > 0)
       p->waits_to_skip--;
    else