From 8340a34a4ae381f596e07475e6fc899f5a612129 Mon Sep 17 00:00:00 2001 From: Sean Bright Date: Thu, 4 Jun 2009 14:53:49 +0000 Subject: [PATCH] Merged revisions 199051 via svnmerge from https://origsvn.digium.com/svn/asterisk/trunk ................ r199051 | seanbright | 2009-06-04 10:31:24 -0400 (Thu, 04 Jun 2009) | 47 lines Merged revisions 199022 via svnmerge from https://origsvn.digium.com/svn/asterisk/branches/1.4 ........ r199022 | seanbright | 2009-06-04 10:14:57 -0400 (Thu, 04 Jun 2009) | 40 lines 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) (closes issue #13778) 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/ ........ ................ git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.0@199052 65c4cc65-6c06-0410-ace0-fbb531ad65f3 --- include/asterisk/_private.h | 12 ++++++ main/asterisk.c | 3 ++ main/loader.c | 81 +++++++++++++++++++++++++++++++++++++ 3 files changed, 96 insertions(+) diff --git a/include/asterisk/_private.h b/include/asterisk/_private.h index b477d0e93c..65437c2b22 100644 --- a/include/asterisk/_private.h +++ b/include/asterisk/_private.h @@ -52,4 +52,16 @@ void ast_autoservice_init(void); /*!< Provided by autoservice.c */ */ 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); + #endif /* _ASTERISK__PRIVATE_H */ diff --git a/main/asterisk.c b/main/asterisk.c index a489400750..b86587d33e 100644 --- a/main/asterisk.c +++ b/main/asterisk.c @@ -3496,6 +3496,9 @@ int main(int argc, char *argv[]) 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 diff --git a/main/loader.c b/main/loader.c index 274078960c..0772db14c2 100644 --- a/main/loader.c +++ b/main/loader.c @@ -110,6 +110,15 @@ static AST_LIST_HEAD_STATIC(updaters, loadupdate); 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 @@ -541,12 +550,84 @@ char *ast_module_helper(const char *line, const char *word, int pos, int state, 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"); return -1; /* reload already in progress */