Fix race in DISCONNECT vs RELEASE

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@881 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_zap.c b/channels/chan_zap.c
index d4192d8c6838ae850bf81d715eb9c789c932bc9b..770f173cefe87cbef4c6ccf6be25619493202f18 100755 (executable)
--- a/channels/chan_zap.c
+++ b/channels/chan_zap.c
@@ -295,18 +295,6 @@ static int pritype = PRI_CPE;
 #define DEFAULT_PRI_DEBUG 0
 #endif
 
-static inline int pri_grab(struct zt_pri *pri)
-{
-       int res;
-       /* Grab the lock first */
-    res = ast_pthread_mutex_lock(&pri->lock);
-       if (res)
-               return res;
-       /* Then break the select */
-       pthread_kill(pri->master, SIGURG);
-       return 0;
-}
-
 static inline void pri_rel(struct zt_pri *pri)
 {
        ast_pthread_mutex_unlock(&pri->lock);
@@ -459,6 +447,26 @@ static struct zt_pvt {
 #endif 
 } *iflist = NULL;
 
+#ifdef ZAPATA_PRI
+static inline int pri_grab(struct zt_pvt *pvt, struct zt_pri *pri)
+{
+       int res;
+       /* Grab the lock first */
+       do {
+           res = pthread_mutex_trylock(&pri->lock);
+               if (res) {
+                       ast_pthread_mutex_unlock(&pvt->lock);
+                       /* Release the lock and try again */
+                       usleep(1);
+                       ast_pthread_mutex_lock(&pvt->lock);
+               }
+       } while(res);
+       /* Then break the select */
+       pthread_kill(pri->master, SIGURG);
+       return 0;
+}
+#endif
+
 static struct zt_ring_cadence cadences[] = {
        { { 125, 125, 2000, 4000 } },                   /* Quick chirp followed by normal ring */
        { { 250, 250, 500, 1000, 250, 250, 500, 4000 } }, /* British style ring */
@@ -1578,7 +1586,7 @@ static int zt_hangup(struct ast_channel *ast)
 #ifdef ZAPATA_PRI
                if (p->sig == SIG_PRI) {
                        if (p->call) {
-                               if (!pri_grab(p->pri)) {
+                               if (!pri_grab(p, p->pri)) {
                                        res = pri_disconnect(p->pri->pri, p->call, PRI_CAUSE_NORMAL_CLEARING);
                                        if (p->alreadyhungup) {
                                                p->call = NULL;
@@ -1688,12 +1696,15 @@ static int zt_answer(struct ast_channel *ast)
        int index;
        int oldstate = ast->_state;
        ast_setstate(ast, AST_STATE_UP);
+       ast_pthread_mutex_lock(&p->lock);
        index = zt_get_index(ast, p, 0);
        if (index < 0)
                index = SUB_REAL;
        /* nothing to do if a radio channel */
-       if (p->radio)
+       if (p->radio) {
+               ast_pthread_mutex_unlock(&p->lock);
                return 0;
+       }
        switch(p->sig) {
        case SIG_FXSLS:
        case SIG_FXSGS:
@@ -1730,7 +1741,7 @@ static int zt_answer(struct ast_channel *ast)
 #ifdef ZAPATA_PRI
        case SIG_PRI:
                /* Send a pri acknowledge */
-               if (!pri_grab(p->pri)) {
+               if (!pri_grab(p, p->pri)) {
                        res = pri_answer(p->pri->pri, p->call, 0, 1);
                        pri_rel(p->pri);
                } else {
@@ -1750,8 +1761,9 @@ static int zt_answer(struct ast_channel *ast)
                return 0;
        default:
                ast_log(LOG_WARNING, "Don't know how to answer signalling %d (channel %d)\n", p->sig, p->channel);
-               return -1;
+               res = -1;
        }
+       ast_pthread_mutex_unlock(&p->lock);
        return res;
 }