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Avoid segfault and race condition when socket is destroyed while listener is in use.

This commit is contained in:
Darren Schreiber 2012-07-05 01:47:07 -07:00
parent 939a26764f
commit 5bc2745472
1 changed files with 18 additions and 7 deletions
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25
src/mod/event_handlers/mod_erlang_event/mod_erlang_event.c
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@ -411,14 +411,20 @@ static switch_xml_t erlang_fetch(const char *sectionstr, const char *tag_name, c
switch_thread_rwlock_rdlock(globals.bindings_rwlock);
for (ptr = bindings.head; ptr; ptr = ptr->next) {
if (ptr->section != section)
continue;
/* Keep the listener from getting pulled out from under us */
switch_thread_rwlock_rdlock(globals.listener_rwlock);
for (ptr = bindings.head; ptr; ptr = ptr->next) {
/* If we got listener_rwlock while a listner thread was dying after removing the listener
from listener_list but before locking for the bindings removal (now pending our lock) check
if it already closed the socket. Our listener pointer should still be good (pointed at an orphan
listener) until it is removed from the binding...*/
if (!ptr->listener) {
switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "NULL pointer binding!\n");
switch_thread_rwlock_unlock(globals.bindings_rwlock);
goto cleanup; /* our pointer is trash */
continue;
}
if (ptr->section != section) {
continue;
}
switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "binding for %s in section %s with key %s and value %s requested from node %s\n", tag_name, sectionstr, key_name, key_value, ptr->process.pid.node);
@ -445,11 +451,14 @@ static switch_xml_t erlang_fetch(const char *sectionstr, const char *tag_name, c
on our condition before the action starts. */
switch_mutex_lock(ptr->listener->sock_mutex);
ei_sendto(ptr->listener->ec, ptr->listener->sockfd, &ptr->process, &buf);
if (ptr->listener->sockfd) {
ei_sendto(ptr->listener->ec, ptr->listener->sockfd, &ptr->process, &buf);
}
switch_mutex_unlock(ptr->listener->sock_mutex);
}
switch_thread_rwlock_unlock(globals.bindings_rwlock);
switch_thread_rwlock_unlock(globals.listener_rwlock);
ei_x_free(&buf);
@ -1243,9 +1252,11 @@ void destroy_listener(listener_t * listener)
switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "Session complete, waiting for children\n");
switch_thread_rwlock_wrlock(listener->rwlock);
switch_mutex_lock(listener->sock_mutex);
if (listener->sockfd) {
close_socket(&listener->sockfd);
}
switch_mutex_unlock(listener->sock_mutex);
switch_core_hash_destroy(&listener->event_hash);