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[mod_event_socket] Fix hangup race with listener_thread of socket application in async mode #636

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Merged
merged 1 commit into from
May 18, 2020
Merged

[mod_event_socket] Fix hangup race with listener_thread of socket application in async mode #636

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37 changes: 27 additions & 10 deletions src/mod/event_handlers/mod_event_socket/mod_event_socket.c
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Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,8 @@ struct listener {
time_t linger_timeout;
struct listener *next;
switch_pollfd_t *pollfd;
uint8_t lock_acquired;
uint8_t finished;
};

typedef struct listener listener_t;
Expand Down Expand Up @@ -163,7 +165,7 @@ SWITCH_DECLARE_GLOBAL_STRING_FUNC(set_pref_ip, prefs.ip);
SWITCH_DECLARE_GLOBAL_STRING_FUNC(set_pref_pass, prefs.password);

static void *SWITCH_THREAD_FUNC listener_run(switch_thread_t *thread, void *obj);
static void launch_listener_thread(listener_t *listener);
static switch_status_t launch_listener_thread(listener_t *listener);

static switch_status_t socket_logger(const switch_log_node_t *node, switch_log_level_t level)
{
Expand Down Expand Up @@ -523,9 +525,17 @@ SWITCH_STANDARD_APP(socket_function)
if (switch_test_flag(listener, LFLAG_ASYNC)) {
const char *var;

launch_listener_thread(listener);
if (launch_listener_thread(listener) != SWITCH_STATUS_SUCCESS) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_ERROR, "Failed to start listener\n");
return;
}

while (switch_channel_ready(channel) && !switch_test_flag(listener, LFLAG_CONNECTED)) {
/* Wait until listener_thread acquires session read lock */
while (!listener->lock_acquired && !listener->finished) {
switch_cond_next();
}

while (switch_channel_ready(channel) && !listener->finished && !switch_test_flag(listener, LFLAG_CONNECTED)) {
switch_cond_next();
}

Expand Down Expand Up @@ -2637,10 +2647,13 @@ static void *SWITCH_THREAD_FUNC listener_run(switch_thread_t *thread, void *obj)

if ((session = listener->session)) {
if (switch_core_session_read_lock(session) != SWITCH_STATUS_SUCCESS) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_ERROR, "Unable to lock session!\n");
switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Unable to lock session!\n");
locked = 0;
session = NULL;
goto done;
}

listener->lock_acquired = 1;
}

if (!listener->sock) {
Expand Down Expand Up @@ -2791,7 +2804,7 @@ static void *SWITCH_THREAD_FUNC listener_run(switch_thread_t *thread, void *obj)
}
switch_mutex_unlock(listener->filter_mutex);

if (listener->session) {
if (listener->session && locked) {
channel = switch_core_session_get_channel(listener->session);
}

Expand Down Expand Up @@ -2823,7 +2836,9 @@ static void *SWITCH_THREAD_FUNC listener_run(switch_thread_t *thread, void *obj)
}

if (listener->session) {
switch_channel_clear_flag(switch_core_session_get_channel(listener->session), CF_CONTROLLED);
if (locked) {
switch_channel_clear_flag(switch_core_session_get_channel(listener->session), CF_CONTROLLED);
}
switch_clear_flag_locked(listener, LFLAG_SESSION);
if (locked) {
switch_core_session_rwunlock(listener->session);
Expand All @@ -2837,20 +2852,22 @@ static void *SWITCH_THREAD_FUNC listener_run(switch_thread_t *thread, void *obj)
prefs.threads--;
switch_mutex_unlock(globals.listener_mutex);

listener->finished = 1;

return NULL;
}


/* Create a thread for the socket and launch it */
static void launch_listener_thread(listener_t *listener)
static switch_status_t launch_listener_thread(listener_t *listener)
{
switch_thread_t *thread;
switch_threadattr_t *thd_attr = NULL;

switch_threadattr_create(&thd_attr, listener->pool);
switch_threadattr_detach_set(thd_attr, 1);
switch_threadattr_stacksize_set(thd_attr, SWITCH_THREAD_STACKSIZE);
switch_thread_create(&thread, thd_attr, listener_run, listener, listener->pool);
return switch_thread_create(&thread, thd_attr, listener_run, listener, listener->pool);
}

static int config(void)
Expand Down Expand Up @@ -3033,8 +3050,8 @@ SWITCH_MODULE_RUNTIME_FUNCTION(mod_event_socket_runtime)
if (switch_socket_addr_get(&listener->sa, SWITCH_TRUE, listener->sock) == SWITCH_STATUS_SUCCESS && listener->sa) {
switch_get_addr(listener->remote_ip, sizeof(listener->remote_ip), listener->sa);
if ((listener->remote_port = switch_sockaddr_get_port(listener->sa))) {
launch_listener_thread(listener);
continue;
if (launch_listener_thread(listener) == SWITCH_STATUS_SUCCESS)
continue;
}
}

Expand Down