Fix from James Olin Oden for a scriptlet deadlock (#146549).

diff --git a/rpmio/rpmsq.c b/rpmio/rpmsq.c
index d0e5044..1ff22f3 100644 (file)
--- a/rpmio/rpmsq.c
+++ b/rpmio/rpmsq.c
@@ -218,7 +218,6 @@ fprintf(stderr, "    Insert(%p): %p\n", ME(), sq);
 
            sq->id = ME();
            ret = pthread_mutex_init(&sq->mutex, NULL);
-           ret = pthread_cond_init(&sq->cond, NULL);
            insque(elem, (prev != NULL ? prev : rpmsqQueue));
            ret = sigrelse(SIGCHLD);
        }
@@ -240,8 +239,11 @@ fprintf(stderr, "    Remove(%p): %p\n", ME(), sq);
        ret = sighold (SIGCHLD);
        if (ret == 0) {
            remque(elem);
-           ret = pthread_cond_destroy(&sq->cond);
-           ret = pthread_mutex_destroy(&sq->mutex);
+          
+           /* Unlock the mutex and then destroy it */ 
+           if((ret = pthread_mutex_unlock(&sq->mutex)) == 0)
+               ret = pthread_mutex_destroy(&sq->mutex);
+
            sq->id = NULL;
 /*@-bounds@*/
            if (sq->pipes[1])   ret = close(sq->pipes[1]);
@@ -315,11 +317,20 @@ void rpmsqAction(int signum,
                     sq != NULL && sq != rpmsqQueue;
                     sq = sq->q_forw)
                {
+                   int ret;
+
                    if (sq->child != reaped)
                        /*@innercontinue@*/ continue;
                    sq->reaped = reaped;
                    sq->status = status;
-                   (void) pthread_cond_signal(&sq->cond);
+
+                   /* Unlock the mutex.  The waiter will then be able to 
+                    * aquire the lock.  
+                    *
+                    * XXX: jbj, wtd, if this fails? 
+                    */
+                   ret = pthread_mutex_unlock(&sq->mutex); 
+
                    /*@innerbreak@*/ break;
                }
            }
@@ -391,6 +402,7 @@ pid_t rpmsqFork(rpmsq sq)
 {
     pid_t pid;
     int xx;
+    int nothreads = 0;   /* XXX: Shouldn't this be a global? */
 
     if (sq->reaper) {
        xx = rpmsqInsert(sq, NULL);
@@ -405,6 +417,24 @@ fprintf(stderr, "    Enable(%p): %p\n", ME(), sq);
 
     xx = sighold(SIGCHLD);
 
+    /* 
+     * Initialize the cond var mutex.   We have to aquire the lock we 
+     * use for the condition before we fork.  Otherwise it is possible for
+     * the child to exit, we get sigchild and the sig handler to send 
+     * the condition signal before we are waiting on the condition.
+     */
+    if (!nothreads) {
+       if(pthread_mutex_lock(&sq->mutex)) {
+           /* Yack we did not get the lock, lets just give up */
+/*@-bounds@*/
+           xx = close(sq->pipes[0]);
+           xx = close(sq->pipes[1]);
+           sq->pipes[0] = sq->pipes[1] = -1;
+/*@=bounds@*/
+           goto out;
+       }
+    }
+
     pid = fork();
     if (pid < (pid_t) 0) {             /* fork failed.  */
 /*@-bounds@*/
@@ -462,10 +492,6 @@ static int rpmsqWaitUnregister(rpmsq sq)
     /* Protect sq->reaped from handler changes. */
     ret = sighold(SIGCHLD);
 
-    /* Initialize the cond var mutex. */
-    if (!nothreads)
-       ret = pthread_mutex_lock(&sq->mutex);
-
     /* Start the child, linux often runs child before parent. */
 /*@-bounds@*/
     if (sq->pipes[0] >= 0)
@@ -486,7 +512,13 @@ static int rpmsqWaitUnregister(rpmsq sq)
            ret = sigpause(SIGCHLD);
        else {
            xx = sigrelse(SIGCHLD);
-           ret = pthread_cond_wait(&sq->cond, &sq->mutex);
+           
+           /* 
+            * We start before the fork with this mutex locked;
+            * The only one that unlocks this the signal handler.
+            * So if we get the lock the child has been reaped.
+            */
+           ret = pthread_mutex_lock(&sq->mutex);
            xx = sighold(SIGCHLD);
        }
     }
@@ -495,9 +527,6 @@ static int rpmsqWaitUnregister(rpmsq sq)
     /* Accumulate stopwatch time spent waiting, potential performance gain. */
     sq->ms_scriptlets += rpmswExit(&sq->op, -1)/1000;
 
-    /* Tear down cond var mutex, our child has been reaped. */
-    if (!nothreads)
-       xx = pthread_mutex_unlock(&sq->mutex);
     xx = sigrelse(SIGCHLD);
 
 #ifdef _RPMSQ_DEBUG