[asterisk-commits] seanbright: branch 1.4 r199022 - in /branches/1.4: include/ main/
SVN commits to the Asterisk project
asterisk-commits at lists.digium.com
Thu Jun 4 09:15:03 CDT 2009
Author: seanbright
Date: Thu Jun 4 09:14:57 2009
New Revision: 199022
URL: http://svn.asterisk.org/svn-view/asterisk?view=rev&rev=199022
Log:
Safely handle AMI connections/reload requests that occur during startup.
During asterisk startup, a lock on the list of modules is obtained by the
primary thread while each module is initialized. Issue 13778 pointed out a
problem with this approach, however. Because the AMI is loaded before other
modules, it is possible for a module reload to be issued by a connected client
(via Action: Command), causing a deadlock.
The resolution for 13778 was to move initialization of the manager to happen
after the other modules had already been lodaded. While this fixed this
particular issue, it caused a problem for users (like FreePBX) who call AMI
scripts via an #exec in a configuration file (See issue 15189).
The solution I have come up with is to defer any reload requests that come in
until after the server is fully booted. When a call comes in to
ast_module_reload (from wherever) before we are fully booted, the request is
added to a queue of pending requests. Once we are done booting up, we then
execute these deferred requests in turn.
Note that I have tried to make this a bit more intelligent in that it will not
queue up more than 1 request for the same module to be reloaded, and if a
general reload request comes in ('module reload') the queue is flushed and we
only issue a single deferred reload for the entire system.
As for how this will impact existing installations - Before 13778, a reload
issued before module initialization was completed would result in a deadlock.
After 13778, you simply couldn't connect to the manager during startup (which
causes problems with #exec-that-calls-AMI configuration files). I believe this
is a good general purpose solution that won't negatively impact existing
installations.
(closes issue #15189)
Reported by: p_lindheimer
Patches:
06032009_15189_deferred_reloads.diff uploaded by seanbright (license 71)
Tested by: p_lindheimer, seanbright
Review: https://reviewboard.asterisk.org/r/272/
Modified:
branches/1.4/include/asterisk.h
branches/1.4/main/asterisk.c
branches/1.4/main/loader.c
Modified: branches/1.4/include/asterisk.h
URL: http://svn.asterisk.org/svn-view/asterisk/branches/1.4/include/asterisk.h?view=diff&rev=199022&r1=199021&r2=199022
==============================================================================
--- branches/1.4/include/asterisk.h (original)
+++ branches/1.4/include/asterisk.h Thu Jun 4 09:14:57 2009
@@ -126,6 +126,18 @@
int ast_module_reload(const char *name);
/*!
+ * \brief Process reload requests received during startup.
+ *
+ * This function requests that the loader execute the pending reload requests
+ * that were queued during server startup.
+ *
+ * \note This function will do nothing if the server has not completely started
+ * up. Once called, the reload queue is emptied, and further invocations
+ * will have no affect.
+ */
+void ast_process_pending_reloads(void);
+
+/*!
* \brief Register a function to be executed before Asterisk exits.
* \param func The callback function to use.
*
Modified: branches/1.4/main/asterisk.c
URL: http://svn.asterisk.org/svn-view/asterisk/branches/1.4/main/asterisk.c?view=diff&rev=199022&r1=199021&r2=199022
==============================================================================
--- branches/1.4/main/asterisk.c (original)
+++ branches/1.4/main/asterisk.c Thu Jun 4 09:14:57 2009
@@ -3111,6 +3111,11 @@
ast_channels_init();
+ if (init_manager()) {
+ printf("%s", term_quit());
+ exit(1);
+ }
+
if (ast_cdr_engine_init()) {
printf("%s", term_quit());
exit(1);
@@ -3156,15 +3161,6 @@
}
if (load_modules(0)) {
- printf("%s", term_quit());
- exit(1);
- }
-
- /* AMI is initialized after loading modules because of a potential
- * conflict between issuing a module reload from manager and
- * registering manager actions. This will cause reversed locking
- * order between the module list and manager actions list. */
- if (init_manager()) {
printf("%s", term_quit());
exit(1);
}
@@ -3184,6 +3180,9 @@
sig_alert_pipe[0] = sig_alert_pipe[1] = -1;
ast_set_flag(&ast_options, AST_OPT_FLAG_FULLY_BOOTED);
+
+ ast_process_pending_reloads();
+
pthread_sigmask(SIG_UNBLOCK, &sigs, NULL);
#ifdef __AST_DEBUG_MALLOC
Modified: branches/1.4/main/loader.c
URL: http://svn.asterisk.org/svn-view/asterisk/branches/1.4/main/loader.c?view=diff&rev=199022&r1=199021&r2=199022
==============================================================================
--- branches/1.4/main/loader.c (original)
+++ branches/1.4/main/loader.c Thu Jun 4 09:14:57 2009
@@ -102,6 +102,15 @@
AST_MUTEX_DEFINE_STATIC(reloadlock);
+struct reload_queue_item {
+ AST_LIST_ENTRY(reload_queue_item) entry;
+ char module[0];
+};
+
+static int do_full_reload = 0;
+
+static AST_LIST_HEAD_STATIC(reload_queue, reload_queue_item);
+
/* when dynamic modules are being loaded, ast_module_register() will
need to know what filename the module was loaded from while it
is being registered
@@ -529,11 +538,83 @@
return ret;
}
+void ast_process_pending_reloads(void)
+{
+ struct reload_queue_item *item;
+
+ if (!ast_fully_booted) {
+ return;
+ }
+
+ AST_LIST_LOCK(&reload_queue);
+
+ if (do_full_reload) {
+ do_full_reload = 0;
+ AST_LIST_UNLOCK(&reload_queue);
+ ast_log(LOG_NOTICE, "Executing deferred reload request.\n");
+ ast_module_reload(NULL);
+ return;
+ }
+
+ while ((item = AST_LIST_REMOVE_HEAD(&reload_queue, entry))) {
+ ast_log(LOG_NOTICE, "Executing deferred reload request for module '%s'.\n", item->module);
+ ast_module_reload(item->module);
+ ast_free(item);
+ }
+
+ AST_LIST_UNLOCK(&reload_queue);
+}
+
+static void queue_reload_request(const char *module)
+{
+ struct reload_queue_item *item;
+
+ AST_LIST_LOCK(&reload_queue);
+
+ if (do_full_reload) {
+ AST_LIST_UNLOCK(&reload_queue);
+ return;
+ }
+
+ if (ast_strlen_zero(module)) {
+ /* A full reload request (when module is NULL) wipes out any previous
+ reload requests and causes the queue to ignore future ones */
+ while ((item = AST_LIST_REMOVE_HEAD(&reload_queue, entry))) {
+ ast_free(item);
+ }
+ do_full_reload = 1;
+ } else {
+ /* No reason to add the same module twice */
+ AST_LIST_TRAVERSE(&reload_queue, item, entry) {
+ if (!strcasecmp(item->module, module)) {
+ AST_LIST_UNLOCK(&reload_queue);
+ return;
+ }
+ }
+ item = ast_calloc(1, sizeof(*item) + strlen(module) + 1);
+ if (!item) {
+ ast_log(LOG_ERROR, "Failed to allocate reload queue item.\n");
+ AST_LIST_UNLOCK(&reload_queue);
+ return;
+ }
+ strcpy(item->module, module);
+ AST_LIST_INSERT_TAIL(&reload_queue, item, entry);
+ }
+ AST_LIST_UNLOCK(&reload_queue);
+}
+
int ast_module_reload(const char *name)
{
struct ast_module *cur;
int res = 0; /* return value. 0 = not found, others, see below */
int i;
+
+ /* If we aren't fully booted, we just pretend we reloaded but we queue this
+ up to run once we are booted up. */
+ if (!ast_fully_booted) {
+ queue_reload_request(name);
+ return 0;
+ }
if (ast_mutex_trylock(&reloadlock)) {
ast_verbose("The previous reload command didn't finish yet\n");
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