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

diff --git a/channels/chan_iax2.c b/channels/chan_iax2.c
index 79f8b619d2b3e7fa19501104a611d07b98d39b63..eca700724c3518efec6cab3c02ef243c63a01a39 100644 (file)
--- a/channels/chan_iax2.c
+++ b/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;
-       reg->callno = 0;
-       registrations = reg;
+       AST_LIST_LOCK(&registrations);
+       AST_LIST_INSERT_HEAD(&registrations, reg, entry);
+       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_peer *peer = NULL;
-       struct iax2_registry *reg, *regl;
+       struct iax2_user *user;
+       struct iax2_peer *peer;
+       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;) {
-               regl = reg;
-               reg = reg->next;
-               if (regl->expire > -1) {
-                       ast_sched_del(sched, regl->expire);
-               }
-               if (regl->callno) {
-                       /* XXX Is this a potential lock?  I don't think so, but you never know */
-                       ast_mutex_lock(&iaxsl[regl->callno]);
-                       if (iaxs[regl->callno]) {
-                               iaxs[regl->callno]->reg = NULL;
-                               iax2_destroy(regl->callno);
+       AST_LIST_LOCK(&registrations);
+       while ((reg = AST_LIST_REMOVE_HEAD(&registrations, entry))) {
+               if (reg->expire > -1)
+                       ast_sched_del(sched, reg->expire);
+               if (reg->callno) {
+                       ast_mutex_lock(&iaxsl[reg->callno]);
+                       if (iaxs[reg->callno]) {
+                               iaxs[reg->callno]->reg = NULL;
+                               iax2_destroy(reg->callno);
                        }
-                       ast_mutex_unlock(&iaxsl[regl->callno]);
+                       ast_mutex_unlock(&iaxsl[reg->callno]);
                }
-               if (regl->dnsmgr)
-                       ast_dnsmgr_release(regl->dnsmgr);
-               free(regl);
+               if (reg->dnsmgr)
+                       ast_dnsmgr_release(reg->dnsmgr);
+               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)