From b4cf033072a8720f93020744d234fc6746b7e057 Mon Sep 17 00:00:00 2001 From: Mark Michelson Date: Wed, 2 Apr 2008 17:36:04 +0000 Subject: [PATCH] Fix a race condition in the manager. It is possible that a new manager event could be appended during a brief time when the manager is not waiting for input. If an event comes during this period, we need to set an indicator that there is an event pending so that the manager doesn't attempt to wait forever for an event that already happened. (closes issue #12354) Reported by: bamby Patches: manager_race_condition.diff uploaded by bamby (license 430) (comments added by me) git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@112468 65c4cc65-6c06-0410-ace0-fbb531ad65f3 --- main/manager.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/main/manager.c b/main/manager.c index 4fadb744ca..10a00a7959 100644 --- a/main/manager.c +++ b/main/manager.c @@ -175,6 +175,7 @@ struct mansession { struct eventqent *eventq; /* Timeout for ast_carefulwrite() */ int writetimeout; + int pending_event; /*!< Pending events indicator in case when waiting_thread is NULL */ AST_LIST_ENTRY(mansession) list; }; @@ -2202,6 +2203,11 @@ static int get_input(struct mansession *s, char *output) fds[0].events = POLLIN; do { ast_mutex_lock(&s->__lock); + if (s->pending_event) { + s->pending_event = 0; + ast_mutex_unlock(&s->__lock); + return 0; + } s->waiting_thread = pthread_self(); ast_mutex_unlock(&s->__lock); @@ -2463,6 +2469,13 @@ int manager_event(int category, const char *event, const char *fmt, ...) ast_mutex_lock(&s->__lock); if (s->waiting_thread != AST_PTHREADT_NULL) pthread_kill(s->waiting_thread, SIGURG); + else + /* We have an event to process, but the mansession is + * not waiting for it. We still need to indicate that there + * is an event waiting so that get_input processes the pending + * event instead of polling. + */ + s->pending_event = 1; ast_mutex_unlock(&s->__lock); } AST_LIST_UNLOCK(&sessions);