Use locking when accessing the registrations list. This list is not actually

used very often, so the likelihood of there being a problem is pretty small,
but still possible.  For example, if the CLI command to list the registrations
was called at the same time that a reload was occurring and the registrations
list was getting destroyed and rebuilt, a crash could occur.

In passing, go ahead and convert this list to use the linked list macros.


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@48363 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_iax2.c

@@ -426,11 +426,11 @@ struct iax2_registry {
 	int messages;				/*!< Message count, low 8 bits = new, high 8 bits = old */
 	int callno;				/*!< Associated call number if applicable */
 	struct sockaddr_in us;			/*!< Who the server thinks we are */
-	struct iax2_registry *next;
 	struct ast_dnsmgr_entry *dnsmgr;	/*!< DNS refresh manager */
+	AST_LIST_ENTRY(iax2_registry) entry;
 };
 
-static struct iax2_registry *registrations;
+static AST_LIST_HEAD_STATIC(registrations, iax2_registry);
 
 /* Don't retry more frequently than every 10 ms, or less frequently than every 5 seconds */
 #define MIN_RETRY_TIME		100
@@ -4242,9 +4242,9 @@ static int iax2_show_registry(int fd, int argc, char *argv[])
 	char perceived[80];
 	if (argc != 3)
 		return RESULT_SHOWUSAGE;
-	AST_LIST_LOCK(&peers);
 	ast_cli(fd, FORMAT2, "Host", "dnsmgr", "Username", "Perceived", "Refresh", "State");
-	for (reg = registrations;reg;reg = reg->next) {
+	AST_LIST_LOCK(&registrations);
+	AST_LIST_TRAVERSE(&registrations, reg, entry) {
 		snprintf(host, sizeof(host), "%s:%d", ast_inet_ntoa(reg->addr.sin_addr), ntohs(reg->addr.sin_port));
 		if (reg->us.sin_addr.s_addr) 
 			snprintf(perceived, sizeof(perceived), "%s:%d", ast_inet_ntoa(reg->us.sin_addr), ntohs(reg->us.sin_port));
@@ -4254,7 +4254,7 @@ static int iax2_show_registry(int fd, int argc, char *argv[])
 					(reg->dnsmgr) ? "Y" : "N", 
 					reg->username, perceived, reg->refresh, regstate2str(reg->regstate));
 	}
-	AST_LIST_UNLOCK(&peers);
+	AST_LIST_UNLOCK(&registrations);
 	return RESULT_SUCCESS;
 #undef FORMAT
 #undef FORMAT2
@@ -5413,9 +5413,9 @@ static int iax2_register(char *value, int lineno)
 	reg->refresh = IAX_DEFAULT_REG_EXPIRE;
 	reg->addr.sin_family = AF_INET;
 	reg->addr.sin_port = porta ? htons(atoi(porta)) : htons(IAX_DEFAULT_PORTNO);
-	reg->next = registrations;
+	AST_LIST_LOCK(&registrations);
-	reg->callno = 0;
+	AST_LIST_INSERT_HEAD(&registrations, reg, entry);
-	registrations = reg;
+	AST_LIST_UNLOCK(&registrations);
 	
 	return 0;
 }
@@ -8622,35 +8622,32 @@ static struct iax2_user *build_user(const char *name, struct ast_variable *v, st
 
 static void delete_users(void)
 {
-	struct iax2_user *user = NULL;
+	struct iax2_user *user;
-	struct iax2_peer *peer = NULL;
+	struct iax2_peer *peer;
-	struct iax2_registry *reg, *regl;
+	struct iax2_registry *reg;
 
 	AST_LIST_LOCK(&users);
 	AST_LIST_TRAVERSE(&users, user, entry)
 		ast_set_flag(user, IAX_DELME);
 	AST_LIST_UNLOCK(&users);
 
-	for (reg = registrations;reg;) {
+	AST_LIST_LOCK(&registrations);
-		regl = reg;
+	while ((reg = AST_LIST_REMOVE_HEAD(&registrations, entry))) {
-		reg = reg->next;
+		if (reg->expire > -1)
-		if (regl->expire > -1) {
+			ast_sched_del(sched, reg->expire);
-			ast_sched_del(sched, regl->expire);
+		if (reg->callno) {
-		}
+			ast_mutex_lock(&iaxsl[reg->callno]);
-		if (regl->callno) {
+			if (iaxs[reg->callno]) {
-			/* XXX Is this a potential lock?  I don't think so, but you never know */
+				iaxs[reg->callno]->reg = NULL;
-			ast_mutex_lock(&iaxsl[regl->callno]);
+				iax2_destroy(reg->callno);
-			if (iaxs[regl->callno]) {
-				iaxs[regl->callno]->reg = NULL;
-				iax2_destroy(regl->callno);
 			}
-			ast_mutex_unlock(&iaxsl[regl->callno]);
+			ast_mutex_unlock(&iaxsl[reg->callno]);
 		}
-		if (regl->dnsmgr)
+		if (reg->dnsmgr)
-			ast_dnsmgr_release(regl->dnsmgr);
+			ast_dnsmgr_release(reg->dnsmgr);
-		free(regl);
+		free(reg);
 	}
-	registrations = NULL;
+	AST_LIST_UNLOCK(&registrations);
 
 	AST_LIST_LOCK(&peers);
 	AST_LIST_TRAVERSE(&peers, peer, entry)
@@ -9092,7 +9089,7 @@ static int reload_config(void)
 {
 	char *config = "iax.conf";
 	struct iax2_registry *reg;
-	struct iax2_peer *peer = NULL;
+	struct iax2_peer *peer;
 
 	strcpy(accountcode, "");
 	strcpy(language, "");
@@ -9105,11 +9102,13 @@ static int reload_config(void)
 	ast_clear_flag((&globalflags), IAX_USEJITTERBUF);	
 	ast_clear_flag((&globalflags), IAX_FORCEJITTERBUF);	
 	delete_users();
-	set_config(config,1);
+	set_config(config, 1);
 	prune_peers();
 	prune_users();
-	for (reg = registrations; reg; reg = reg->next)
+	AST_LIST_LOCK(&registrations);
+	AST_LIST_TRAVERSE(&registrations, reg, entry)
 		iax2_do_register(reg);
+	AST_LIST_UNLOCK(&registrations);
 	/* Qualify hosts, too */
 	AST_LIST_LOCK(&peers);
 	AST_LIST_TRAVERSE(&peers, peer, entry)
@@ -10024,8 +10023,11 @@ static int load_module(void)
 		ast_netsock_release(netsock);
 	}
 
-	for (reg = registrations; reg; reg = reg->next)
+	AST_LIST_LOCK(&registrations);
+	AST_LIST_TRAVERSE(&registrations, reg, entry)
 		iax2_do_register(reg);
+	AST_LIST_UNLOCK(&registrations);	
+
 	AST_LIST_LOCK(&peers);
 	AST_LIST_TRAVERSE(&peers, peer, entry) {
 		if (peer->sockfd < 0)