From b0ac62573a6282a0114d2b23e5a6f04e472fb051 Mon Sep 17 00:00:00 2001 From: "Kevin P. Fleming" Date: Sat, 25 Mar 2006 23:22:44 +0000 Subject: revert loader changes that have clearly not undergone adequate testing before commit git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@14952 65c4cc65-6c06-0410-ace0-fbb531ad65f3 --- loader.c | 501 ++++++--------------------------------------------------------- 1 file changed, 41 insertions(+), 460 deletions(-) (limited to 'loader.c') diff --git a/loader.c b/loader.c index d9908e5f5..2639b98c5 100644 --- a/loader.c +++ b/loader.c @@ -33,7 +33,6 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$") -#include "asterisk/linkedlists.h" #include "asterisk/module.h" #include "asterisk/options.h" #include "asterisk/config.h" @@ -57,29 +56,13 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$") #define RTLD_NOW 0 #endif + static int modlistver = 0; /* increase whenever the list changes, to protect reload */ static unsigned char expected_key[] = { 0x8e, 0x93, 0x22, 0x83, 0xf5, 0xc3, 0xc0, 0x75, 0xff, 0x8b, 0xa9, 0xbe, 0x7c, 0x43, 0x74, 0x63 }; -/* - * Modules can be in a number of different states, as below: - * MS_FAILED attempt to load failed. This is final. - * MS_NEW just added to the list, symbols unresolved. - * MS_RESOLVED all symbols resolved, but supplier modules not active yet. - * MS_CANLOAD all symbols resolved and suppliers are all active - * (or we are in a cyclic dependency and we are breaking a loop) - * MS_ACTIVE load() returned successfully. - */ -enum st_t { /* possible states of a module */ - MS_FAILED = 0, /* cannot load */ - MS_NEW = 1, /* nothing known */ - MS_RESOLVED = 2, /* all required resolved */ - MS_CANLOAD = 3, /* as above, plus cyclic depend.*/ - MS_ACTIVE = 4, /* all done */ -}; - /* * All module symbols are in module_symbols. * Modules are then linked in a list of struct module, @@ -90,18 +73,21 @@ enum st_t { /* possible states of a module */ * * A second lock, reloadlock, is used to prevent concurrent reloads */ + +struct module_symbols { + int (*load_module)(void); + int (*unload_module)(void); + int (*usecount)(void); + char *(*description)(void); + char *(*key)(void); + int (*reload)(void); +}; + struct module { AST_LIST_ENTRY(module) next; struct module_symbols cb; void *lib; /* the shared lib */ char resource[256]; - - enum st_t state; - int export_refcount; /* how many users of exported symbols */ - - ast_mutex_t mtx; /* for future use */ - struct localuser *lu; - int localusecnt; }; @@ -114,340 +100,6 @@ static AST_LIST_HEAD_STATIC(module_list, module); static AST_LIST_HEAD_STATIC(updaters, loadupdate); AST_MUTEX_DEFINE_STATIC(reloadlock); -/* - * helper localuser routines. - * All of these routines are extremely expensive, so the use of - * macros is totally unnecessary from the point of view of performance: - * the extra function call will be totally negligible in all cases. - */ - -struct localuser *ast_localuser_add(struct ast_module_lock *m, - struct ast_channel *chan) -{ - struct localuser *u = ast_calloc(1, sizeof(*u)); - if (u == NULL) - return NULL; - u->chan = chan; - ast_mutex_lock(&m->lock); - AST_LIST_INSERT_HEAD(&m->u, u, next); - m->usecnt++; - ast_mutex_unlock(&m->lock); - ast_update_use_count(); - return u; -} - -void ast_localuser_remove(struct ast_module_lock *m, struct localuser *u) -{ - ast_mutex_lock(&m->lock); - AST_LIST_REMOVE(&m->u, u, next); - m->usecnt--; - free(u); - ast_mutex_unlock(&m->lock); - ast_update_use_count(); -} - -void ast_hangup_localusers(struct ast_module_lock *m) -{ - struct localuser *u; - ast_mutex_lock(&m->lock); - AST_LIST_TRAVERSE_SAFE_BEGIN(&m->u, u, next) { - ast_softhangup(u->chan, AST_SOFTHANGUP_APPUNLOAD); - free(u); - AST_LIST_REMOVE_CURRENT(&m->u, next); - } - AST_LIST_TRAVERSE_SAFE_END - m->usecnt = 0; - ast_mutex_unlock(&m->lock); - ast_update_use_count(); -} - -/*--- new-style loader routines ---*/ - -/* - * For backward compatibility, we have 3 types of loadable modules: - * - * MOD_0 these are the 'old style' modules, which export a number - * of callbacks, and their full interface, as globally visible - * symbols. The module needs to be loaded with RTLD_LAZY and - * RTLD_GLOBAL to make symbols visible to other modules, and - * to avoid load failures due to cross dependencies. - * - * MOD_1 almost as above, but the generic callbacks are all into a - * a structure, mod_data. Same load requirements as above. - * - * MOD_2 this is the 'new style' format for modules. The module must - * explictly declare which simbols are exported and which - * symbols from other modules are used, and the code in this - * loader will implement appropriate checks to load the modules - * in the correct order. Also this allows to load modules - * with RTLD_NOW and RTLD_LOCAL so there is no chance of run-time - * bugs due to unresolved symbols or name conflicts. - */ - -/* - * helper routine to print the symbolic name associated to a state - */ -static const char *st_name(enum st_t state) -{ - /* try to resolve required symbols */ - const char *st; - switch (state) { -#define ST(x) case x: st = # x; break; - ST(MS_NEW); - ST(MS_FAILED); - ST(MS_RESOLVED); - ST(MS_ACTIVE); - ST(MS_CANLOAD); - default: - st = "unknown"; - } - return st; -#undef ST -} - -/*! \brief - * Fetch/release an exported symbol - modify export_refcount by delta - * \param delta 1 to fetch a symbol, -1 to release it. - * on success, return symbol value. - * Note, modules in MS_FAIL will never match in a 'get' request. - * If src is non-NULL, on exit *src points to the source module. - * - * Must be called with the lock held. - */ -static void *module_symbol_helper(const char *name, - int delta, struct module **src) -{ - void *ret = NULL; - struct module *m; - - AST_LIST_TRAVERSE(&module_list, m, next) { - struct symbol_entry *es; - if (delta > 0 && m->state == MS_FAILED) - continue; /* cannot 'get' a symbol from a failed module */ - for (es = m->cb.exported_symbols; ret == NULL && es && es->name; es++) { - if (!strcmp(es->name, name)) { - ret = es->value; - m->export_refcount += delta; - if (src) - *src = m; - break; - } - } - if (ret) - break; - } - if (ret == NULL) - ast_log(LOG_WARNING, "symbol %s not found\n", name); - return ret; -} - -static void *release_module_symbol(const char *name) -{ - return module_symbol_helper(name, -1, NULL); -} - -static void *get_module_symbol(const char *name, struct module **src) -{ - return module_symbol_helper(name, +1, src); -} - -/*! - * \brief Release refcounts to all imported symbols, - * and change module state to MS_FAILED. - */ -static void release_module(struct module *m) -{ - struct symbol_entry *s; - - for (s = m->cb.required_symbols; s && s->name != NULL; s++) { - if (s->value != NULL) { - release_module_symbol(s->name); - s->value = NULL; - } - } - m->state = MS_FAILED; -} - -/*! \brief check that no NULL symbols are exported - the algorithms rely on that. */ -static int check_exported(struct module *m) -{ - struct symbol_entry *es = m->cb.exported_symbols; - int errors = 0; - - if (es == NULL) - return 0; - ast_log(LOG_WARNING, "module %s exports the following symbols\n", - es->name); - for (; es->name; es++) { - void **p = es->value; - int i; - - ast_log(LOG_WARNING, "\taddr %p size %8d %s\n", - es->value, es->size, es->name); - for (i = 0; i < es->size / sizeof(void *); i++, p++) { - if (*p == NULL) { - ast_log(LOG_WARNING, "\t *** null field at offset %d\n", i); - errors++; - } - } - } - return errors; -} - -/*! - * \brief Resolve symbols and change state accordingly. - * Return 1 if state changed, 0 otherwise. - * If MS_FAILED, MS_ACTIVE or MS_CANLOAD there is nothing to do. - * If a symbol cannot be resolved (no supplier or supplier in MS_FAIL), - * move to MS_FAIL and release all symbols; - * If all suppliers are MS_ACTIVE, move to MS_CANLOAD - * otherwise move to MS_RESOLVED. - */ -static int resolve(struct module *m) -{ - struct symbol_entry *s; - - if (m->state == MS_FAILED || m->state == MS_ACTIVE || m->state == MS_CANLOAD) - return 0; /* already decided what to do */ - /* now it's either MS_NEW or MS_RESOLVED. - * Be optimistic and put it in MS_CANLOAD, then try to - * resolve and verify symbols, and downgrade as appropriate. - */ - m->state = MS_CANLOAD; - for (s = m->cb.required_symbols; s && s->name != NULL; s++) { - void **p = (void **)(s->value); - - if (*p == NULL) /* symbol not resolved yet */ - *p = get_module_symbol(s->name, &s->src); - if (*p == NULL || s->src->state == MS_FAILED) { /* fail */ - ast_log(LOG_WARNING, - "Unresolved symbol %s for module %s\n", - s->name, m->resource); - release_module(m); /* and set to MS_FAILED */ - break; - } - if (s->src->state != MS_ACTIVE) - m->state = MS_RESOLVED; /* downgrade */ - } - return 1; -} - -/* - * Fixup references and load modules according to their dependency order. - * Called when new modules are added to the list. - * The algorithm is as follows: - * - all modules MS_FAILED are changed to MS_NEW, in case something - * happened that could help them. - * - first try to resolve symbols. If successful, change the - * module's state to MS_RESOLVED otherwise to MS_FAILED - * - repeat on all modules until there is progress: - * . if it is MS_ACTIVE or MS_FAILED, continue (no progress) - * . if one has all required modules in MS_ACTIVE, try to load it. - * If successful it becomes MS_ACTIVE itself, otherwise - * MS_FAILED and releases all symbols. - * In any case, we have progress. - * . if one of the dependencies is MS_FAILED, release and set to - * MS_FAILED here too. We have progress. - * - if we have no progress there is a cyclic dependency. - * Take first and change to MS_CANLOAD, i.e. as if all required are - * MS_ACTIVE. we have progress, so repeat. - * NOTE: - * must be called with lock held - * recursive calls simply return success. - */ -static int fixup(const char *caller) -{ - struct module *m; - int total = 0, new = 0, cycle = 0; - static int in_fixup = 0; /* disable recursive calls */ - - if (in_fixup) - return 0; - in_fixup++; - AST_LIST_TRAVERSE(&module_list, m, next) { - total++; - if (m->state == MS_FAILED) - m->state = MS_NEW; - if (m->state == MS_NEW) - new++; - /* print some debugging info for new modules */ - if (m->state == MS_NEW && - (m->cb.exported_symbols || m->cb.required_symbols)) - ast_log(LOG_WARNING, - "module %-30s exports %p requires %p state %s(%d)\n", - m->resource, m->cb.exported_symbols, - m->cb.required_symbols, - st_name(m->state), m->state); - } - ast_log(LOG_WARNING, "---- fixup (%s): %d modules, %d new ---\n", - caller, total, new); - for (;;cycle++) { - int again = 0; /* set if we need another round */ - - ast_log(LOG_WARNING, "---- fixup: cycle %d ---\n", cycle); - AST_LIST_TRAVERSE(&module_list, m, next) { - if (resolve(m)) - again = 1; /* something changed */ - if (m->state != MS_CANLOAD) /* for now, done with this module */ - continue; - /* try to run the load routine */ - if (m->cb.load_module()) { /* error */ - ast_log(LOG_WARNING, "load_module %s fail\n", - m->resource); - release_module(m); /* and set to MS_FAIL */ - } else { - ast_log(LOG_WARNING, "load_module %s success\n", - m->resource); - m->state = MS_ACTIVE; - } - again = 1; /* something has changed */ - } - /* Modules in MS_RESOLVED mean a possible cyclic dependency. - * Break the indecision by setting one to CANLOAD, and repeat. - */ - AST_LIST_TRAVERSE(&module_list, m, next) { - if (m->state == MS_RESOLVED) { - m->state = MS_CANLOAD; - again = 1; - break; - } - } - if (!again) /* we are done */ - break; - } - ast_log(LOG_WARNING, "---- fixup complete ---\n"); - in_fixup--; - return 0; -} - -/* test routines to see which modules depend on global symbols - * exported by other modules. - */ -static void check_symbols(void) -{ - struct dirent *d; - DIR *mods = opendir(ast_config_AST_MODULE_DIR); - void *lib; - char buf[1024]; - - ast_log(LOG_WARNING, "module dir <%s>\n", ast_config_AST_MODULE_DIR); - if (!mods) - return; - while((d = readdir(mods))) { - int ld = strlen(d->d_name); - /* Must end in .so to load it. */ - if (ld <= 3 || strcasecmp(d->d_name + ld - 3, ".so")) - continue; - snprintf(buf, sizeof(buf), "%s/%s", ast_config_AST_MODULE_DIR, d->d_name); - lib = dlopen(buf, RTLD_NOW | RTLD_LOCAL); - if (lib == NULL) { - ast_log(LOG_WARNING, "module %s error %s\n", d->d_name, dlerror()); - } - dlclose(lib); - } -} -/*--- end new-style routines ---*/ - /* * In addition to modules, the reload command handles some extra keywords * which are listed here together with the corresponding handlers. @@ -530,7 +182,6 @@ int ast_unload_resource(const char *resource_name, int force) } else ast_log(LOG_WARNING, "** Dangerous **: Unloading resource anyway, at user request\n"); } - release_module(cur); /* bookkeeping */ AST_LIST_REMOVE_CURRENT(&module_list, next); dlclose(cur->lib); free(cur); @@ -571,24 +222,6 @@ char *ast_module_helper(const char *line, const char *word, int pos, int state, return ret; } -/*! - * \brief Given a function address, find the corresponding module. - * This is required as a workaround to the fact that we do not - * have a module argument to the load_module() function. - * Hopefully the performance implications are small. - */ -struct module *ast_find_module(int (*load_fn)(void)) -{ - struct module *cur; - AST_LIST_LOCK(&module_list); - AST_LIST_TRAVERSE(&module_list, cur, next) { - if (cur->cb.load_module == load_fn) - break; - } - AST_LIST_UNLOCK(&module_list); - return cur; -} - int ast_module_reload(const char *name) { struct module *cur; @@ -672,14 +305,13 @@ static void *find_symbol(struct module *m, const char *name, int verbose) } /* XXX cfg is only used for !res_* and #ifdef RTLD_GLOBAL */ -static struct module * __load_resource(const char *resource_name, - const struct ast_config *cfg) +static int __load_resource(const char *resource_name, const struct ast_config *cfg) { static char fn[256]; int errors=0; int res; struct module *cur; - struct module_symbols *m, *m1; + struct module_symbols *m; int flags=RTLD_NOW; unsigned char *key; char tmp[80]; @@ -707,11 +339,11 @@ static struct module * __load_resource(const char *resource_name, if (resource_exists(resource_name, 0)) { ast_log(LOG_WARNING, "Module '%s' already exists\n", resource_name); AST_LIST_UNLOCK(&module_list); - return NULL; + return -1; } if (!(cur = ast_calloc(1, sizeof(*cur)))) { AST_LIST_UNLOCK(&module_list); - return NULL; + return -1; } m = &cur->cb; ast_copy_string(cur->resource, resource_name, sizeof(cur->resource)); @@ -719,45 +351,29 @@ static struct module * __load_resource(const char *resource_name, ast_copy_string(fn, resource_name, sizeof(fn)); else snprintf(fn, sizeof(fn), "%s/%s", ast_config_AST_MODULE_DIR, resource_name); - /* first, open in a sane way */ - cur->lib = dlopen(fn, RTLD_NOW | RTLD_LOCAL); - if (cur->lib == NULL) { - ast_log(LOG_WARNING, "test %s\n", dlerror()); - } else - dlclose(cur->lib); - cur->lib = dlopen(fn, flags); if (!cur->lib) { ast_log(LOG_WARNING, "%s\n", dlerror()); free(cur); AST_LIST_UNLOCK(&module_list); - return NULL; - } - m1 = find_symbol(cur, "mod_data", 0); - if (m1 != NULL) { /* new style module */ - errors = check_exported(cur); - *m = *m1; - if (m->type == MOD_2) - ast_log(LOG_WARNING, "new style %s, should unload and reload with RTLD_LOCAL\n", resource_name); - } else { - m->type = MOD_0; - m->load_module = find_symbol(cur, "load_module", 1); - m->unload_module = find_symbol(cur, "unload_module", 1); - m->usecount = find_symbol(cur, "usecount", 1); - m->description = find_symbol(cur, "description", 1); - m->key = find_symbol(cur, "key", 1); - m->reload = find_symbol(cur, "reload", 0); + return -1; } + m->load_module = find_symbol(cur, "load_module", 1); if (!m->load_module) errors++; + m->unload_module = find_symbol(cur, "unload_module", 1); if (!m->unload_module) errors++; + m->usecount = find_symbol(cur, "usecount", 1); if (!m->usecount) errors++; + m->description = find_symbol(cur, "description", 1); if (!m->description) errors++; + m->key = find_symbol(cur, "key", 1); if (!m->key) errors++; + m->reload = find_symbol(cur, "reload", 0); if (!m->key || !(key = (unsigned char *) m->key())) { ast_log(LOG_WARNING, "Key routine returned NULL in module %s\n", fn); key = NULL; @@ -772,7 +388,7 @@ static struct module * __load_resource(const char *resource_name, dlclose(cur->lib); free(cur); AST_LIST_UNLOCK(&module_list); - return NULL; + return -1; } if (!ast_fully_booted) { if (option_verbose) @@ -789,64 +405,30 @@ static struct module * __load_resource(const char *resource_name, so reload commands will be issued in same order modules were loaded */ modlistver++; - if (m->type == MOD_2) { - ast_log(LOG_WARNING, "new-style module %s, deferring load()\n", - resource_name); - cur->state = MS_NEW; - } else - cur->state = MS_CANLOAD; - /* XXX TODO: make sure the usecount is 1 before releasing the lock */ AST_LIST_UNLOCK(&module_list); - - if (cur->state == MS_CANLOAD && (res = m->load_module())) { + if ((res = m->load_module())) { ast_log(LOG_WARNING, "%s: load_module failed, returning %d\n", resource_name, res); ast_unload_resource(resource_name, 0); - return NULL; + return -1; } - cur->state = MS_ACTIVE; ast_update_use_count(); - return cur; + return 0; } -/* - * load a single module (API call). - * (recursive calls from load_module() succeed. - * Returns 0 on success, -1 on error. - */ int ast_load_resource(const char *resource_name) { - int o = option_verbose; + int res, o = option_verbose; struct ast_config *cfg = NULL; - struct module *m; option_verbose = 0; /* Keep the module file parsing silent */ cfg = ast_config_load(AST_MODULE_CONFIG); option_verbose = o; /* restore verbosity */ - m = __load_resource(resource_name, cfg); + res = __load_resource(resource_name, cfg); if (cfg) ast_config_destroy(cfg); - return m ? 0 : -1; + return res; } -#if 0 -/* - * load a single module (API call). - * (recursive calls from load_module() succeed. - */ -int ast_load_resource(const char *resource_name) -{ - struct module *m; - int ret; - - ast_mutex_lock(&modlock); - m = __load_resource(resource_name, 0); - fixup(resource_name); - ret = (m->state == MS_FAILED) ? -1 : 0; - ast_mutex_unlock(&modlock); - return ret; -} -#endif - /* if enabled, log and output on console the module's name, and try load it */ static int print_and_load(const char *s, struct ast_config *cfg) { @@ -859,7 +441,7 @@ static int print_and_load(const char *s, struct ast_config *cfg) term_color(tmp, s, COLOR_BRWHITE, 0, sizeof(tmp))); fflush(stdout); } - if (__load_resource(s, cfg)) + if (!__load_resource(s, cfg)) return 0; /* success */ ast_log(LOG_WARNING, "Loading module %s failed!\n", s); return -1; @@ -876,6 +458,7 @@ static const char *loadorder[] = int load_modules(const int preload_only) { struct ast_config *cfg; + struct ast_variable *v; int x; if (option_verbose) { @@ -884,13 +467,9 @@ int load_modules(const int preload_only) "Asterisk Dynamic Loader Starting:\n"); } - check_symbols(); - cfg = ast_config_load(AST_MODULE_CONFIG); - if (cfg) { const char *cmd = preload_only ? "preload" : "load"; - struct ast_variable *v; /* Load explicitly defined modules */ for (v = ast_variable_browse(cfg, "modules"); v; v = v->next) { if (strcasecmp(v->name, cmd)) /* not what we are looking for */ @@ -902,12 +481,16 @@ int load_modules(const int preload_only) } } - if (preload_only) - goto done; + if (preload_only) { + ast_config_destroy(cfg); + return 0; + } - if (cfg && !ast_true(ast_variable_retrieve(cfg, "modules", "autoload"))) + if (cfg && !ast_true(ast_variable_retrieve(cfg, "modules", "autoload"))) { /* no autoload */ - goto done; + ast_config_destroy(cfg); + return 0; + } /* * Load all modules. To help resolving dependencies, we load modules * in the order defined by loadorder[], with the final step for @@ -934,10 +517,9 @@ int load_modules(const int preload_only) !strcasecmp(d->d_name + ld - 3, ".so") && !resource_exists(d->d_name, 1)) { /* It's a shared library, check if we are allowed to load it - * (very inefficient, but oh well). + * (very inefficient, but oh well. */ if (cfg) { - struct ast_variable *v; for (v = ast_variable_browse(cfg, "modules"); v; v = v->next) { if (!strcasecmp(v->name, "noload") && !strcasecmp(v->value, d->d_name)) @@ -961,8 +543,6 @@ int load_modules(const int preload_only) } closedir(mods); } -done: - fixup("load_modules"); ast_config_destroy(cfg); return 0; } @@ -977,6 +557,7 @@ void ast_update_use_count(void) AST_LIST_TRAVERSE(&updaters, m, next) m->updater(); AST_LIST_UNLOCK(&module_list); + } int ast_update_module_list(int (*modentry)(const char *module, const char *description, int usecnt, const char *like), -- cgit v1.2.3