<p>Corey Farrell has uploaded this change for <strong>review</strong>.</p><p><a href="https://gerrit.asterisk.org/7873">View Change</a></p><pre style="font-family: monospace,monospace; white-space: pre-wrap;">loader: Process module dependencies.<br><br>* Add string vectors for requires, optional_apis and enhances.<br>* Add reffed_deps module vector for holding references to dependencies.<br>* Initialize string vectors after final dlopen of each module.<br>* Free string vectors and clear references from reffed_deps in<br> module_destroy.<br>* Create functions necessary to process module dependencies and enforce<br> load order.<br><br>Module dependencies result in automatic references being managed by the<br>module loader. This enforces unload order.<br><br>Change-Id: I9be08d1dd331aceadc1dcba00b804d71360b2fbb<br>---<br>M main/loader.c<br>1 file changed, 407 insertions(+), 23 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/73/7873/1</pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">diff --git a/main/loader.c b/main/loader.c<br>index 88c1cda..8f15b07 100644<br>--- a/main/loader.c<br>+++ b/main/loader.c<br>@@ -89,6 +89,12 @@<br> </managerEvent><br> ***/<br> <br>+#if defined(OPTIONAL_API)<br>+#define HAS_OPTIONAL_API 1<br>+#else<br>+#define HAS_OPTIONAL_API 0<br>+#endif<br>+<br> #ifndef RTLD_NOW<br> #define RTLD_NOW 0<br> #endif<br>@@ -127,6 +133,21 @@<br> int usecount;<br> /*! List of users holding the module. */<br> struct module_user_list users;<br>+<br>+ /*! List of required module names. */<br>+ struct ast_vector_string requires;<br>+ /*! List of optional api modules. */<br>+ struct ast_vector_string optional_apis;<br>+ /*! List of modules this enhances. */<br>+ struct ast_vector_string enhances;<br>+<br>+ /*!<br>+ * \brief Vector holding pointers to modules we have a reference to.<br>+ *<br>+ * When one module requires another, the required module gets added<br>+ * to this list with a reference.<br>+ */<br>+ struct module_vector reffed_deps;<br> struct {<br> /*! The module running and ready to accept requests. */<br> unsigned int running:1;<br>@@ -161,6 +182,233 @@<br> * >0 a_pri > b_pri<br> */<br> return a_pri - b_pri;<br>+}<br>+<br>+static struct ast_module *find_resource(const char *resource, int do_lock);<br>+<br>+/*!<br>+ * \internal<br>+ * \brief Add a reference from mod to dep.<br>+ *<br>+ * \param mod Owner of the new reference.<br>+ * \param dep Module to reference<br>+ * \param missing Vector to store name of \a dep if it is not running.<br>+ *<br>+ * This function returns failure if \a dep is not running and \a missing<br>+ * is NULL. If \a missing is not NULL errors will only be returned for<br>+ * allocation failures.<br>+ *<br>+ * \retval 0 Success<br>+ * \retval -1 Failure<br>+ *<br>+ * \note Adding a second reference to the same dep will return success<br>+ * without doing anything.<br>+ */<br>+static int module_reffed_deps_add(struct ast_module *mod, struct ast_module *dep,<br>+ struct ast_vector_const_string *missing)<br>+{<br>+ if (!dep->flags.running) {<br>+ return !missing ? -1 : AST_VECTOR_APPEND(missing, dep->info->name);<br>+ }<br>+<br>+ if (AST_VECTOR_GET_CMP(&mod->reffed_deps, dep, AST_VECTOR_ELEM_DEFAULT_CMP)) {<br>+ /* Skip duplicate. */<br>+ return 0;<br>+ }<br>+<br>+ if (AST_VECTOR_APPEND(&mod->reffed_deps, dep)) {<br>+ return -1;<br>+ }<br>+<br>+ ast_module_ref(dep);<br>+<br>+ return 0;<br>+}<br>+<br>+/*!<br>+ * \internal<br>+ * \brief Add references for modules that enhance a dependency.<br>+ *<br>+ * \param mod Owner of the new references.<br>+ * \param dep Module to check for enhancers.<br>+ * \param missing Vector to store name of any enhancer that is not running or declined.<br>+ *<br>+ * \retval 0 Success<br>+ * \retval -1 Failure<br>+ */<br>+static int module_reffed_deps_add_dep_enhancers(struct ast_module *mod,<br>+ struct ast_module *dep, struct ast_vector_const_string *missing)<br>+{<br>+ struct ast_module *cur;<br>+<br>+ AST_DLLIST_TRAVERSE(&module_list, cur, entry) {<br>+ if (cur->flags.declined) {<br>+ continue;<br>+ }<br>+<br>+ if (!AST_VECTOR_GET_CMP(&cur->enhances, dep->info->name, !strcasecmp)) {<br>+ /* dep is not enhanced by cur. */<br>+ continue;<br>+ }<br>+<br>+ /* dep is enhanced by cur, therefore mod requires cur. */<br>+ if (module_reffed_deps_add(mod, cur, missing)) {<br>+ return -1;<br>+ }<br>+ }<br>+<br>+ return 0;<br>+}<br>+<br>+/*!<br>+ * \internal<br>+ * \brief Add references to a list of dependencies.<br>+ *<br>+ * \param mod Owner of the new references.<br>+ * \param vec List of required modules to process<br>+ * \param missing Vector to store names of modules that are not running.<br>+ * \param ref_enhancers Reference all enhancers of each required module.<br>+ * \param isoptional Modules that are not loaded can be ignored.<br>+ *<br>+ * \retval 0 Success<br>+ * \retval -1 Failure<br>+ */<br>+static int module_deps_process_reqlist(struct ast_module *mod,<br>+ struct ast_vector_string *vec, struct ast_vector_const_string *missing,<br>+ int ref_enhancers, int isoptional)<br>+{<br>+ int idx;<br>+<br>+ for (idx = 0; idx < AST_VECTOR_SIZE(vec); idx++) {<br>+ const char *depname = AST_VECTOR_GET(vec, idx);<br>+ struct ast_module *dep = find_resource(depname, 0);<br>+<br>+ if (!dep || !dep->flags.running) {<br>+ if (isoptional && !dep) {<br>+ continue;<br>+ }<br>+<br>+ if (missing && !AST_VECTOR_APPEND(missing, depname)) {<br>+ continue;<br>+ }<br>+<br>+ return -1;<br>+ }<br>+<br>+ if (module_reffed_deps_add(mod, dep, missing)) {<br>+ return -1;<br>+ }<br>+<br>+ if (ref_enhancers && module_reffed_deps_add_dep_enhancers(mod, dep, missing)) {<br>+ return -1;<br>+ }<br>+ }<br>+<br>+ return 0;<br>+}<br>+<br>+/*!<br>+ * \internal<br>+ * \brief Grab all references required to start the module.<br>+ *<br>+ * \param mod The module we're trying to start.<br>+ * \param missing Vector to store a list of missing dependencies.<br>+ *<br>+ * \retval 0 Success<br>+ * \retval -1 Failure<br>+ *<br>+ * \note module_list must be locked.<br>+ *<br>+ * \note Caller is responsible for initializing and freeing the vector on<br>+ * success. Elements are only safe read while module_list remains locked.<br>+ */<br>+static int module_deps_reference(struct ast_module *mod, struct ast_vector_const_string *missing)<br>+{<br>+ int res = 0;<br>+<br>+ /* Grab references to modules we enhance but not other enhancements. */<br>+ res |= module_deps_process_reqlist(mod, &mod->enhances, missing, 0, 0);<br>+<br>+ /* Grab references to modules we require plus enhancements. */<br>+ res |= module_deps_process_reqlist(mod, &mod->requires, missing, 1, 0);<br>+<br>+ /* Grab references to optional api modules including enhancements. */<br>+ res |= module_deps_process_reqlist(mod, &mod->optional_apis, missing, 1, HAS_OPTIONAL_API);<br>+<br>+ if (!res) {<br>+ return 0;<br>+ }<br>+<br>+ if (missing) {<br>+ /* We had an allocation error so the list was incomplete anyways. */<br>+ AST_VECTOR_FREE(missing);<br>+ }<br>+<br>+ return -1;<br>+}<br>+<br>+/*!<br>+ * \brief Recursively find required dependencies that are not running.<br>+ *<br>+ * \param mod Module to scan for dependencies.<br>+ * \param missingdeps Vector listing modules that must be started first.<br>+ *<br>+ * \retval 0 All dependencies resolved.<br>+ * \retval -1 Failed to resolve some dependencies.<br>+ *<br>+ * An error from this function usually means a required module is not even<br>+ * loaded. This function is safe from infinite recursion, but dependency<br>+ * loops are not reported as an error from here. On success missingdeps<br>+ * will contain a list of every module that needs to be running before this<br>+ * module can start.<br>+ */<br>+static int module_deps_missing_recursive(struct ast_module *mod, struct module_vector *missingdeps)<br>+{<br>+ int i = 0;<br>+ int res = -1;<br>+ struct ast_vector_const_string localdeps;<br>+ struct ast_module *tmp;<br>+<br>+ /*<br>+ * localdeps stores a copy of all dependencies that mod could not reference.<br>+ * First we discard modules that we've already found. We add all newly found<br>+ * modules to the missingdeps vector then scan them recursively. This will<br>+ * ensure we quickly run out of stuff to do.<br>+ */<br>+ AST_VECTOR_INIT(&localdeps, 0);<br>+ if (module_deps_reference(mod, &localdeps)) {<br>+ goto clean_return;<br>+ }<br>+<br>+ while (i < AST_VECTOR_SIZE(&localdeps)) {<br>+ tmp = find_resource(AST_VECTOR_GET(&localdeps, i), 0);<br>+<br>+ if (!tmp) {<br>+ goto clean_return;<br>+ }<br>+<br>+ if (AST_VECTOR_GET_CMP(missingdeps, tmp, AST_VECTOR_ELEM_DEFAULT_CMP)) {<br>+ AST_VECTOR_REMOVE(&localdeps, i, 0);<br>+ } else {<br>+ /* missingdeps is the real list so keep it sorted. */<br>+ if (AST_VECTOR_ADD_SORTED(missingdeps, tmp, module_vector_cmp)) {<br>+ goto clean_return;<br>+ }<br>+ i++;<br>+ }<br>+ }<br>+<br>+ res = 0;<br>+ for (i = 0; !res && i < AST_VECTOR_SIZE(&localdeps); i++) {<br>+ tmp = find_resource(AST_VECTOR_GET(&localdeps, i), 0);<br>+ /* We've already confirmed tmp is loaded in the first loop. */<br>+ res = module_deps_missing_recursive(tmp, missingdeps);<br>+ }<br>+<br>+clean_return:<br>+ AST_VECTOR_FREE(&localdeps);<br>+<br>+ return res;<br> }<br> <br> const char *ast_module_name(const struct ast_module *mod)<br>@@ -244,6 +492,18 @@<br> <br> static void module_destroy(struct ast_module *mod)<br> {<br>+ AST_VECTOR_CALLBACK_VOID(&mod->requires, ast_free);<br>+ AST_VECTOR_FREE(&mod->requires);<br>+<br>+ AST_VECTOR_CALLBACK_VOID(&mod->optional_apis, ast_free);<br>+ AST_VECTOR_FREE(&mod->optional_apis);<br>+<br>+ AST_VECTOR_CALLBACK_VOID(&mod->enhances, ast_free);<br>+ AST_VECTOR_FREE(&mod->enhances);<br>+<br>+ AST_VECTOR_CALLBACK_VOID(&mod->reffed_deps, ast_module_unref);<br>+ AST_VECTOR_FREE(&mod->reffed_deps);<br>+<br> AST_LIST_HEAD_DESTROY(&mod->users);<br> ao2_cleanup(mod->ref_debug);<br> ast_free(mod);<br>@@ -267,7 +527,7 @@<br> AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_END;<br> AST_DLLIST_UNLOCK(&module_list);<br> <br>- if (mod) {<br>+ if (mod && !mod->usecount) {<br> ast_debug(5, "Unregistering module %s\n", info->name);<br> module_destroy(mod);<br> }<br>@@ -1117,6 +1377,21 @@<br> return AST_MODULE_LOAD_FAILURE;<br> }<br> <br>+ if (module_deps_reference(mod, NULL)) {<br>+ struct module_vector missing;<br>+ int i;<br>+<br>+ AST_VECTOR_INIT(&missing, 0);<br>+ if (module_deps_missing_recursive(mod, &missing)) {<br>+ ast_log(LOG_ERROR, "%s has one or more unknown dependencies.\n", mod->info->name);<br>+ }<br>+ for (i = 0; i < AST_VECTOR_SIZE(&missing); i++) {<br>+ ast_log(LOG_ERROR, "%s loaded before dependency %s!\n", mod->info->name,<br>+ AST_VECTOR_GET(&missing, i)->info->name);<br>+ }<br>+ AST_VECTOR_FREE(&missing);<br>+ }<br>+<br> if (!ast_fully_booted) {<br> ast_verb(1, "Loading %s.\n", mod->resource);<br> }<br>@@ -1184,6 +1459,17 @@<br> }<br> return required ? AST_MODULE_LOAD_FAILURE : AST_MODULE_LOAD_DECLINE;<br> }<br>+<br>+ /* Split lists from mod->info. */<br>+ res = ast_vector_string_create(&mod->requires, mod->info->requires, ",", strcasecmp);<br>+ res |= ast_vector_string_create(&mod->optional_apis, mod->info->optional_apis, ",", strcasecmp);<br>+ res |= ast_vector_string_create(&mod->enhances, mod->info->enhances, ",", strcasecmp);<br>+ if (res) {<br>+ ast_log(LOG_WARNING, "Failed to initialize dependency structures for module '%s'.\n", resource_name);<br>+ unload_dynamic_module(mod);<br>+<br>+ return required ? AST_MODULE_LOAD_FAILURE : AST_MODULE_LOAD_DECLINE;<br>+ }<br> }<br> <br> if (inspect_module(mod)) {<br>@@ -1198,6 +1484,12 @@<br> }<br> res = AST_MODULE_LOAD_PRIORITY;<br> } else {<br>+ if (module_deps_reference(mod, NULL)) {<br>+ ast_log(LOG_WARNING, "Module '%s' could not be loaded due to missing dependencies.\n", resource_name);<br>+ unload_dynamic_module(mod);<br>+<br>+ return required ? AST_MODULE_LOAD_FAILURE : AST_MODULE_LOAD_DECLINE;<br>+ }<br> res = start_resource(mod);<br> }<br> <br>@@ -1255,6 +1547,119 @@<br> }<br> <br> AST_LIST_HEAD_NOLOCK(load_retries, load_order_entry);<br>+<br>+static enum ast_module_load_result start_resource_attempt(struct ast_module *mod, int *count)<br>+{<br>+ enum ast_module_load_result lres;<br>+<br>+ /* Try to grab required references. */<br>+ if (module_deps_reference(mod, NULL)) {<br>+ /* We're likely to retry so not an error. */<br>+ ast_debug(1, "Module %s is missing dependencies\n", mod->resource);<br>+ return AST_MODULE_LOAD_SKIP;<br>+ }<br>+<br>+ lres = start_resource(mod);<br>+ ast_debug(3, "START: %-46s[%d] %d\n",<br>+ mod->resource,<br>+ ast_test_flag(mod->info, AST_MODFLAG_LOAD_ORDER) ? mod->info->load_pri : AST_MODPRI_DEFAULT,<br>+ lres);<br>+<br>+ if (lres == AST_MODULE_LOAD_SUCCESS) {<br>+ (*count)++;<br>+ } else if (lres == AST_MODULE_LOAD_FAILURE) {<br>+ ast_log(LOG_ERROR, "*** Failed to load module %s\n", mod->resource);<br>+ }<br>+<br>+ return lres;<br>+}<br>+<br>+static int start_resource_list(struct module_vector *resources, int *mod_count)<br>+{<br>+ struct module_vector missingdeps;<br>+ int res = 0;<br>+<br>+ AST_VECTOR_INIT(&missingdeps, 0);<br>+ while (AST_VECTOR_SIZE(resources)) {<br>+ struct ast_module *mod = AST_VECTOR_REMOVE(resources, 0, 1);<br>+ enum ast_module_load_result lres;<br>+<br>+ lres = start_resource_attempt(mod, mod_count);<br>+ if (lres == AST_MODULE_LOAD_SUCCESS) {<br>+ /* No missing dependencies, successful. */<br>+ continue;<br>+ }<br>+<br>+ if (lres == AST_MODULE_LOAD_FAILURE) {<br>+ ast_log(LOG_ERROR, "Failed to load %s.\n", ast_module_name(mod));<br>+ res = -1;<br>+ break;<br>+ }<br>+<br>+ if (lres == AST_MODULE_LOAD_DECLINE) {<br>+ /* BUGBUG: Need to exempt from enhances and optional_apis. */<br>+ continue;<br>+ }<br>+<br>+ res = module_deps_missing_recursive(mod, &missingdeps);<br>+ if (res) {<br>+ break;<br>+ }<br>+<br>+ if (!AST_VECTOR_SIZE(&missingdeps)) {<br>+ ast_log(LOG_WARNING, "%s isn't missing any dependencies but still didn't start\n",<br>+ ast_module_name(mod));<br>+ /* Dependencies were met but the module failed to start. */<br>+ res = -1;<br>+ break;<br>+ }<br>+<br>+ ast_debug(1, "%s has %d dependencies\n",<br>+ ast_module_name(mod), (int)AST_VECTOR_SIZE(&missingdeps));<br>+ while (AST_VECTOR_SIZE(&missingdeps)) {<br>+ int didwork = 0;<br>+ int i = 0;<br>+<br>+ while (i < AST_VECTOR_SIZE(&missingdeps)) {<br>+ struct ast_module *tmp = AST_VECTOR_GET(&missingdeps, i);<br>+<br>+ ast_debug(1, "%s trying to start %s\n", ast_module_name(mod), ast_module_name(tmp));<br>+ if (!start_resource_attempt(tmp, mod_count)) {<br>+ ast_debug(1, "%s started %s\n", ast_module_name(mod), ast_module_name(tmp));<br>+ AST_VECTOR_REMOVE(&missingdeps, i, 1);<br>+ AST_VECTOR_REMOVE_CMP_ORDERED(resources, tmp,<br>+ AST_VECTOR_ELEM_DEFAULT_CMP, AST_VECTOR_ELEM_CLEANUP_NOOP);<br>+ didwork++;<br>+ continue;<br>+ }<br>+ ast_debug(1, "%s failed to start %s\n", ast_module_name(mod), ast_module_name(tmp));<br>+ i++;<br>+ }<br>+<br>+ if (!didwork) {<br>+ break;<br>+ }<br>+ }<br>+<br>+ if (AST_VECTOR_SIZE(&missingdeps)) {<br>+ ast_log(LOG_ERROR, "Failed to load %s due to unfilled dependencies.\n",<br>+ ast_module_name(mod));<br>+ /* We've failed to mod because of dependencies. Really abort? */<br>+ res = -1;<br>+ break;<br>+ }<br>+<br>+ res = start_resource_attempt(mod, mod_count);<br>+ if (res) {<br>+ ast_log(LOG_ERROR, "Failed to load %s: %d\n", ast_module_name(mod), res);<br>+ break;<br>+ }<br>+ }<br>+<br>+ AST_VECTOR_FREE(&missingdeps);<br>+<br>+ return res;<br>+}<br> <br> /*! loads modules in order by load_pri, updates mod_count<br> \return -1 on failure to load module, -2 on failure to load required module, otherwise 0<br>@@ -1358,30 +1763,9 @@<br> AST_LIST_TRAVERSE_SAFE_END;<br> }<br> <br>- /* second remove modules from heap sorted by priority */<br>- for (i = 0; i < AST_VECTOR_SIZE(&resource_heap); i++) {<br>- struct ast_module *mod = AST_VECTOR_GET(&resource_heap, i);<br>- enum ast_module_load_result lres;<br>-<br>- lres = start_resource(mod);<br>- ast_debug(3, "START: %-46s %d %d\n", mod->resource, lres, global_symbols);<br>- switch (lres) {<br>- case AST_MODULE_LOAD_SUCCESS:<br>- count++;<br>- case AST_MODULE_LOAD_DECLINE:<br>- break;<br>- case AST_MODULE_LOAD_FAILURE:<br>- ast_log(LOG_ERROR, "*** Failed to load module %s\n", mod->resource);<br>- res = -1;<br>- goto done;<br>- case AST_MODULE_LOAD_SKIP:<br>- case AST_MODULE_LOAD_PRIORITY:<br>- break;<br>- }<br>- }<br>+ res = start_resource_list(&resource_heap, &count);<br> <br> done:<br>-<br> while ((order = AST_LIST_REMOVE_HEAD(&load_retries, entry))) {<br> ast_free(order->resource);<br> ast_free(order);<br></pre><p>To view, visit <a href="https://gerrit.asterisk.org/7873">change 7873</a>. To unsubscribe, visit <a href="https://gerrit.asterisk.org/settings">settings</a>.</p><div itemscope itemtype="http://schema.org/EmailMessage"><div itemscope itemprop="action" itemtype="http://schema.org/ViewAction"><link itemprop="url" href="https://gerrit.asterisk.org/7873"/><meta itemprop="name" content="View Change"/></div></div>
<div style="display:none"> Gerrit-Project: asterisk </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-MessageType: newchange </div>
<div style="display:none"> Gerrit-Change-Id: I9be08d1dd331aceadc1dcba00b804d71360b2fbb </div>
<div style="display:none"> Gerrit-Change-Number: 7873 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: Corey Farrell <git@cfware.com> </div>