Properly lock slave and master in zt_unlink (bug #1008)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@2208 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_zap.c b/channels/chan_zap.c
index eb4cc05..81fd90f 100755 (executable)
--- a/channels/chan_zap.c
+++ b/channels/chan_zap.c
@@ -2196,13 +2196,23 @@ int     x;
        return 0;
 }
 
-static void zt_unlink(struct zt_pvt *slave, struct zt_pvt *master)
+static void zt_unlink(struct zt_pvt *slave, struct zt_pvt *master, int needlock)
 {
        /* Unlink a specific slave or all slaves/masters from a given master */
        int x;
        int hasslaves;
        if (!master)
                return;
+       if (needlock) {
+               ast_mutex_lock(&master->lock);
+               if (slave) {
+                       while(ast_mutex_trylock(&slave->lock)) {
+                               ast_mutex_unlock(&master->lock);
+                               usleep(1);
+                               ast_mutex_lock(&master->lock);
+                       }
+               }
+       }
        hasslaves = 0;
        for (x=0;x<MAX_SLAVES;x++) {
                if (master->slaves[x]) {
@@ -2237,6 +2247,11 @@ static void zt_unlink(struct zt_pvt *slave, struct zt_pvt *master)
                master->master = NULL;
        }
        update_conf(master);
+       if (needlock) {
+               if (slave)
+                       ast_mutex_unlock(&slave->lock);
+               ast_mutex_unlock(&master->lock);
+       }
 }
 
 static void zt_link(struct zt_pvt *slave, struct zt_pvt *master) {
@@ -2456,7 +2471,7 @@ static int zt_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags,
                        (oi1 != i1) ||
                        (oi2 != i2)) {
                        if (slave && master)
-                               zt_unlink(slave, master);
+                               zt_unlink(slave, master, 1);
                        ast_log(LOG_DEBUG, "Something changed out on %d/%d to %d/%d, returning -3 to restart\n",
                                                                        op0->channel, oi1, op1->channel, oi2);
                        if (op0 == p0)
@@ -2484,7 +2499,7 @@ static int zt_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags,
                        *fo = NULL;
                        *rc = who;
                        if (slave && master)
-                               zt_unlink(slave, master);
+                               zt_unlink(slave, master, 1);
                        if (op0 == p0)
                                zt_enable_ec(p0);
                        if (op1 == p1)
@@ -2497,7 +2512,7 @@ static int zt_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags,
                                *fo = f;
                                *rc = who;
                                if (slave && master)
-                                       zt_unlink(slave, master);
+                                       zt_unlink(slave, master, 1);
                                return 0;
                        } else if ((who == c0) && p0->pulsedial) {
                                ast_write(c1, f);
@@ -2520,18 +2535,20 @@ static int zt_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
 {
        struct zt_pvt *p = newchan->pvt->pvt;
        int x;
+       ast_mutex_lock(&p->lock);
        ast_log(LOG_DEBUG, "New owner for channel %d is %s\n", p->channel, newchan->name);
        if (p->owner == oldchan)
                p->owner = newchan;
        for (x=0;x<3;x++)
                if (p->subs[x].owner == oldchan) {
                        if (!x)
-                               zt_unlink(NULL, p);
+                               zt_unlink(NULL, p, 0);
                        p->subs[x].owner = newchan;
                }
        if (newchan->_state == AST_STATE_RINGING) 
                zt_indicate(newchan, AST_CONTROL_RINGING);
        update_conf(p);
+       ast_mutex_unlock(&p->lock);
        return 0;
 }