Fri Aug 24 02:22:16 2007

Asterisk developer's documentation


loader.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 1999 - 2006, Digium, Inc.
00005  *
00006  * Mark Spencer <markster@digium.com>
00007  * Kevin P. Fleming <kpfleming@digium.com>
00008  * Luigi Rizzo <rizzo@icir.org>
00009  *
00010  * See http://www.asterisk.org for more information about
00011  * the Asterisk project. Please do not directly contact
00012  * any of the maintainers of this project for assistance;
00013  * the project provides a web site, mailing lists and IRC
00014  * channels for your use.
00015  *
00016  * This program is free software, distributed under the terms of
00017  * the GNU General Public License Version 2. See the LICENSE file
00018  * at the top of the source tree.
00019  */
00020 
00021 /*! \file
00022  *
00023  * \brief Module Loader
00024  * \author Mark Spencer <markster@digium.com>
00025  * \author Kevin P. Fleming <kpfleming@digium.com>
00026  * \author Luigi Rizzo <rizzo@icir.org>
00027  * - See ModMngMnt
00028  */
00029 
00030 #include "asterisk.h"
00031 
00032 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
00033 
00034 #include <stdio.h>
00035 #include <dirent.h>
00036 #include <unistd.h>
00037 #include <stdlib.h>
00038 #include <errno.h>
00039 #include <string.h>
00040 
00041 #include "asterisk/linkedlists.h"
00042 #include "asterisk/module.h"
00043 #include "asterisk/options.h"
00044 #include "asterisk/config.h"
00045 #include "asterisk/logger.h"
00046 #include "asterisk/channel.h"
00047 #include "asterisk/term.h"
00048 #include "asterisk/manager.h"
00049 #include "asterisk/cdr.h"
00050 #include "asterisk/enum.h"
00051 #include "asterisk/rtp.h"
00052 #include "asterisk/http.h"
00053 #include "asterisk/lock.h"
00054 
00055 #ifdef DLFCNCOMPAT
00056 #include "asterisk/dlfcn-compat.h"
00057 #else
00058 #include <dlfcn.h>
00059 #endif
00060 
00061 #include "asterisk/md5.h"
00062 #include "asterisk/utils.h"
00063 
00064 #ifndef RTLD_NOW
00065 #define RTLD_NOW 0
00066 #endif
00067 
00068 struct ast_module_user {
00069    struct ast_channel *chan;
00070    AST_LIST_ENTRY(ast_module_user) entry;
00071 };
00072 
00073 AST_LIST_HEAD(module_user_list, ast_module_user);
00074 
00075 static unsigned char expected_key[] =
00076 { 0x87, 0x76, 0x79, 0x35, 0x23, 0xea, 0x3a, 0xd3,
00077   0x25, 0x2a, 0xbb, 0x35, 0x87, 0xe4, 0x22, 0x24 };
00078 
00079 static unsigned int embedding = 1; /* we always start out by registering embedded modules,
00080                   since they are here before we dlopen() any
00081                */
00082 
00083 struct ast_module {
00084    const struct ast_module_info *info;
00085    void *lib;              /* the shared lib, or NULL if embedded */
00086    int usecount;              /* the number of 'users' currently in this module */
00087    struct module_user_list users;         /* the list of users in the module */
00088    struct {
00089       unsigned int running:1;
00090       unsigned int declined:1;
00091    } flags;
00092    AST_LIST_ENTRY(ast_module) entry;
00093    char resource[0];
00094 };
00095 
00096 static AST_LIST_HEAD_STATIC(module_list, ast_module);
00097 
00098 struct loadupdate {
00099    int (*updater)(void);
00100    AST_LIST_ENTRY(loadupdate) entry;
00101 };
00102 
00103 static AST_LIST_HEAD_STATIC(updaters, loadupdate);
00104 
00105 AST_MUTEX_DEFINE_STATIC(reloadlock);
00106 
00107 /* when dynamic modules are being loaded, ast_module_register() will
00108    need to know what filename the module was loaded from while it
00109    is being registered
00110 */
00111 struct ast_module *resource_being_loaded;
00112 
00113 /* XXX: should we check for duplicate resource names here? */
00114 
00115 void ast_module_register(const struct ast_module_info *info)
00116 {
00117    struct ast_module *mod;
00118 
00119    if (embedding) {
00120       if (!(mod = ast_calloc(1, sizeof(*mod) + strlen(info->name) + 1)))
00121          return;
00122       strcpy(mod->resource, info->name);
00123    } else {
00124       mod = resource_being_loaded;
00125    }
00126 
00127    mod->info = info;
00128    AST_LIST_HEAD_INIT(&mod->users);
00129 
00130    /* during startup, before the loader has been initialized,
00131       there are no threads, so there is no need to take the lock
00132       on this list to manipulate it. it is also possible that it
00133       might be unsafe to use the list lock at that point... so
00134       let's avoid it altogether
00135    */
00136    if (!embedding)
00137       AST_LIST_LOCK(&module_list);
00138 
00139    /* it is paramount that the new entry be placed at the tail of
00140       the list, otherwise the code that uses dlopen() to load
00141       dynamic modules won't be able to find out if the module it
00142       just opened was registered or failed to load
00143    */
00144    AST_LIST_INSERT_TAIL(&module_list, mod, entry);
00145 
00146    if (!embedding)
00147       AST_LIST_UNLOCK(&module_list);
00148 
00149    /* give the module a copy of its own handle, for later use in registrations and the like */
00150    *((struct ast_module **) &(info->self)) = mod;
00151 }
00152 
00153 void ast_module_unregister(const struct ast_module_info *info)
00154 {
00155    struct ast_module *mod = NULL;
00156 
00157    /* it is assumed that the users list in the module structure
00158       will already be empty, or we cannot have gotten to this
00159       point
00160    */
00161    AST_LIST_LOCK(&module_list);
00162    AST_LIST_TRAVERSE_SAFE_BEGIN(&module_list, mod, entry) {
00163       if (mod->info == info) {
00164          AST_LIST_REMOVE_CURRENT(&module_list, entry);
00165          break;
00166       }
00167    }
00168    AST_LIST_TRAVERSE_SAFE_END;
00169    AST_LIST_UNLOCK(&module_list);
00170 
00171    if (mod) {
00172       AST_LIST_HEAD_DESTROY(&mod->users);
00173       free(mod);
00174    }
00175 }
00176 
00177 struct ast_module_user *__ast_module_user_add(struct ast_module *mod,
00178                      struct ast_channel *chan)
00179 {
00180    struct ast_module_user *u = ast_calloc(1, sizeof(*u));
00181 
00182    if (!u)
00183       return NULL;
00184 
00185    u->chan = chan;
00186 
00187    AST_LIST_LOCK(&mod->users);
00188    AST_LIST_INSERT_HEAD(&mod->users, u, entry);
00189    AST_LIST_UNLOCK(&mod->users);
00190 
00191    ast_atomic_fetchadd_int(&mod->usecount, +1);
00192 
00193    ast_update_use_count();
00194 
00195    return u;
00196 }
00197 
00198 void __ast_module_user_remove(struct ast_module *mod, struct ast_module_user *u)
00199 {
00200    AST_LIST_LOCK(&mod->users);
00201    AST_LIST_REMOVE(&mod->users, u, entry);
00202    AST_LIST_UNLOCK(&mod->users);
00203    ast_atomic_fetchadd_int(&mod->usecount, -1);
00204    free(u);
00205 
00206    ast_update_use_count();
00207 }
00208 
00209 void __ast_module_user_hangup_all(struct ast_module *mod)
00210 {
00211    struct ast_module_user *u;
00212 
00213    AST_LIST_LOCK(&mod->users);
00214    while ((u = AST_LIST_REMOVE_HEAD(&mod->users, entry))) {
00215       ast_softhangup(u->chan, AST_SOFTHANGUP_APPUNLOAD);
00216       ast_atomic_fetchadd_int(&mod->usecount, -1);
00217       free(u);
00218    }
00219    AST_LIST_UNLOCK(&mod->users);
00220 
00221         ast_update_use_count();
00222 }
00223 
00224 /*! \note
00225  * In addition to modules, the reload command handles some extra keywords
00226  * which are listed here together with the corresponding handlers.
00227  * This table is also used by the command completion code.
00228  */
00229 static struct reload_classes {
00230    const char *name;
00231    int (*reload_fn)(void);
00232 } reload_classes[] = {  /* list in alpha order, longest match first for cli completion */
00233    { "cdr", ast_cdr_engine_reload },
00234    { "dnsmgr", dnsmgr_reload },
00235    { "extconfig", read_config_maps },
00236    { "enum",   ast_enum_reload },
00237    { "manager",   reload_manager },
00238    { "rtp", ast_rtp_reload },
00239    { "http",   ast_http_reload },
00240    { NULL,  NULL }
00241 };
00242 
00243 static int printdigest(const unsigned char *d)
00244 {
00245    int x, pos;
00246    char buf[256]; /* large enough so we don't have to worry */
00247 
00248    for (pos = 0, x = 0; x < 16; x++)
00249       pos += sprintf(buf + pos, " %02x", *d++);
00250 
00251    ast_log(LOG_DEBUG, "Unexpected signature:%s\n", buf);
00252 
00253    return 0;
00254 }
00255 
00256 static int key_matches(const unsigned char *key1, const unsigned char *key2)
00257 {
00258    int x;
00259 
00260    for (x = 0; x < 16; x++) {
00261       if (key1[x] != key2[x])
00262          return 0;
00263    }
00264 
00265    return 1;
00266 }
00267 
00268 static int verify_key(const unsigned char *key)
00269 {
00270    struct MD5Context c;
00271    unsigned char digest[16];
00272 
00273    MD5Init(&c);
00274    MD5Update(&c, key, strlen((char *)key));
00275    MD5Final(digest, &c);
00276 
00277    if (key_matches(expected_key, digest))
00278       return 0;
00279 
00280    printdigest(digest);
00281 
00282    return -1;
00283 }
00284 
00285 static int resource_name_match(const char *name1_in, const char *name2_in)
00286 {
00287    char *name1 = (char *) name1_in;
00288    char *name2 = (char *) name2_in;
00289 
00290    /* trim off any .so extensions */
00291    if (!strcasecmp(name1 + strlen(name1) - 3, ".so")) {
00292       name1 = ast_strdupa(name1);
00293       name1[strlen(name1) - 3] = '\0';
00294    }
00295    if (!strcasecmp(name2 + strlen(name2) - 3, ".so")) {
00296       name2 = ast_strdupa(name2);
00297       name2[strlen(name2) - 3] = '\0';
00298    }
00299 
00300    return strcasecmp(name1, name2);
00301 }
00302 
00303 static struct ast_module *find_resource(const char *resource, int do_lock)
00304 {
00305    struct ast_module *cur;
00306 
00307    if (do_lock)
00308       AST_LIST_LOCK(&module_list);
00309 
00310    AST_LIST_TRAVERSE(&module_list, cur, entry) {
00311       if (!resource_name_match(resource, cur->resource))
00312          break;
00313    }
00314 
00315    if (do_lock)
00316       AST_LIST_UNLOCK(&module_list);
00317 
00318    return cur;
00319 }
00320 
00321 #if LOADABLE_MODULES
00322 static void unload_dynamic_module(struct ast_module *mod)
00323 {
00324    void *lib = mod->lib;
00325 
00326    /* WARNING: the structure pointed to by mod is going to
00327       disappear when this operation succeeds, so we can't
00328       dereference it */
00329 
00330    if (lib)
00331       while (!dlclose(lib));
00332 }
00333 
00334 static struct ast_module *load_dynamic_module(const char *resource_in, unsigned int global_symbols_only)
00335 {
00336    char fn[256];
00337    void *lib;
00338    struct ast_module *mod;
00339    char *resource = (char *) resource_in;
00340    unsigned int wants_global;
00341 
00342    if (strcasecmp(resource + strlen(resource) - 3, ".so")) {
00343       resource = alloca(strlen(resource_in) + 3);
00344            strcpy(resource, resource_in);
00345       strcat(resource, ".so");
00346    }
00347 
00348    snprintf(fn, sizeof(fn), "%s/%s", ast_config_AST_MODULE_DIR, resource);
00349 
00350    /* make a first load of the module in 'quiet' mode... don't try to resolve
00351       any symbols, and don't export any symbols. this will allow us to peek into
00352       the module's info block (if available) to see what flags it has set */
00353 
00354    if (!(resource_being_loaded = ast_calloc(1, sizeof(*resource_being_loaded) + strlen(resource) + 1)))
00355       return NULL;
00356 
00357    strcpy(resource_being_loaded->resource, resource);
00358 
00359    if (!(lib = dlopen(fn, RTLD_LAZY | RTLD_LOCAL))) {
00360       ast_log(LOG_WARNING, "Error loading module '%s': %s\n", resource_in, dlerror());
00361       free(resource_being_loaded);
00362       return NULL;
00363    }
00364 
00365    /* the dlopen() succeeded, let's find out if the module
00366       registered itself */
00367    /* note that this will only work properly as long as
00368       ast_module_register() (which is called by the module's
00369       constructor) places the new module at the tail of the
00370       module_list
00371    */
00372    if (resource_being_loaded != (mod = AST_LIST_LAST(&module_list))) {
00373       ast_log(LOG_WARNING, "Module '%s' did not register itself during load\n", resource_in);
00374       /* no, it did not, so close it and return */
00375       while (!dlclose(lib));
00376       /* note that the module's destructor will call ast_module_unregister(),
00377          which will free the structure we allocated in resource_being_loaded */
00378       return NULL;
00379    }
00380 
00381    wants_global = ast_test_flag(mod->info, AST_MODFLAG_GLOBAL_SYMBOLS);
00382 
00383    /* if we are being asked only to load modules that provide global symbols,
00384       and this one does not, then close it and return */
00385    if (global_symbols_only && !wants_global) {
00386       while (!dlclose(lib));
00387       return NULL;
00388    }
00389 
00390    /* if the system supports RTLD_NOLOAD, we can just 'promote' the flags
00391       on the already-opened library to what we want... if not, we have to
00392       close it and start over
00393    */
00394 #if defined(HAVE_RTLD_NOLOAD) && !defined(__Darwin__)
00395    if (!dlopen(fn, RTLD_NOLOAD | (wants_global ? RTLD_LAZY | RTLD_GLOBAL : RTLD_NOW | RTLD_LOCAL))) {
00396       ast_log(LOG_WARNING, "Unable to promote flags on module '%s': %s\n", resource_in, dlerror());
00397       while (!dlclose(lib));
00398       free(resource_being_loaded);
00399       return NULL;
00400    }
00401 #else
00402    while (!dlclose(lib));
00403    resource_being_loaded = NULL;
00404 
00405    /* start the load process again */
00406 
00407    if (!(resource_being_loaded = ast_calloc(1, sizeof(*resource_being_loaded) + strlen(resource) + 1)))
00408       return NULL;
00409 
00410    strcpy(resource_being_loaded->resource, resource);
00411 
00412    if (!(lib = dlopen(fn, wants_global ? RTLD_LAZY | RTLD_GLOBAL : RTLD_NOW | RTLD_LOCAL))) {
00413       ast_log(LOG_WARNING, "Error loading module '%s': %s\n", resource_in, dlerror());
00414       free(resource_being_loaded);
00415       return NULL;
00416    }
00417 
00418    /* since the module was successfully opened, and it registered itself
00419       the previous time we did that, we're going to assume it worked this
00420       time too :) */
00421 #endif
00422 
00423    AST_LIST_LAST(&module_list)->lib = lib;
00424    resource_being_loaded = NULL;
00425 
00426    return AST_LIST_LAST(&module_list);
00427 }
00428 #endif
00429 
00430 void ast_module_shutdown(void)
00431 {
00432    struct ast_module *mod;
00433    AST_LIST_HEAD_NOLOCK_STATIC(local_module_list, ast_module);
00434 
00435    /* We have to call the unload() callbacks in reverse order that the modules
00436     * exist in the module list so it is the reverse order of how they were
00437     * loaded. */
00438 
00439    AST_LIST_LOCK(&module_list);
00440    while ((mod = AST_LIST_REMOVE_HEAD(&module_list, entry)))
00441       AST_LIST_INSERT_HEAD(&local_module_list, mod, entry);
00442    AST_LIST_UNLOCK(&module_list);
00443 
00444    while ((mod = AST_LIST_REMOVE_HEAD(&local_module_list, entry))) {
00445       if (mod->info->unload)
00446          mod->info->unload();
00447       /* Since this should only be called when shutting down "gracefully",
00448        * all channels should be down before we get to this point, meaning
00449        * there will be no module users left. */
00450       AST_LIST_HEAD_DESTROY(&mod->users);
00451       free(mod);
00452    }
00453 }
00454 
00455 int ast_unload_resource(const char *resource_name, enum ast_module_unload_mode force)
00456 {
00457    struct ast_module *mod;
00458    int res = -1;
00459    int error = 0;
00460 
00461    AST_LIST_LOCK(&module_list);
00462 
00463    if (!(mod = find_resource(resource_name, 0))) {
00464       AST_LIST_UNLOCK(&module_list);
00465       return 0;
00466    }
00467 
00468    if (!(mod->flags.running || mod->flags.declined))
00469       error = 1;
00470 
00471    if (!mod->lib) {
00472       ast_log(LOG_WARNING, "Unloading embedded modules is not supported.\n");
00473       error = 1;
00474    }
00475 
00476    if (!error && (mod->usecount > 0)) {
00477       if (force)
00478          ast_log(LOG_WARNING, "Warning:  Forcing removal of module '%s' with use count %d\n",
00479             resource_name, mod->usecount);
00480       else {
00481          ast_log(LOG_WARNING, "Soft unload failed, '%s' has use count %d\n", resource_name,
00482             mod->usecount);
00483          error = 1;
00484       }
00485    }
00486 
00487    if (!error) {
00488       __ast_module_user_hangup_all(mod);
00489       res = mod->info->unload();
00490 
00491       if (res) {
00492          ast_log(LOG_WARNING, "Firm unload failed for %s\n", resource_name);
00493          if (force <= AST_FORCE_FIRM)
00494             error = 1;
00495          else
00496             ast_log(LOG_WARNING, "** Dangerous **: Unloading resource anyway, at user request\n");
00497       }
00498    }
00499 
00500    if (!error)
00501       mod->flags.running = mod->flags.declined = 0;
00502 
00503    AST_LIST_UNLOCK(&module_list);
00504 
00505 #if LOADABLE_MODULES
00506    if (!error)
00507       unload_dynamic_module(mod);
00508 #endif
00509 
00510    if (!error)
00511       ast_update_use_count();
00512 
00513    return res;
00514 }
00515 
00516 char *ast_module_helper(const char *line, const char *word, int pos, int state, int rpos, int needsreload)
00517 {
00518    struct ast_module *cur;
00519    int i, which=0, l = strlen(word);
00520    char *ret = NULL;
00521 
00522    if (pos != rpos)
00523       return NULL;
00524 
00525    AST_LIST_LOCK(&module_list);
00526    AST_LIST_TRAVERSE(&module_list, cur, entry) {
00527       if (!strncasecmp(word, cur->resource, l) &&
00528           (cur->info->reload || !needsreload) &&
00529           ++which > state) {
00530          ret = strdup(cur->resource);
00531          break;
00532       }
00533    }
00534    AST_LIST_UNLOCK(&module_list);
00535 
00536    if (!ret) {
00537       for (i=0; !ret && reload_classes[i].name; i++) {
00538          if (!strncasecmp(word, reload_classes[i].name, l) && ++which > state)
00539             ret = strdup(reload_classes[i].name);
00540       }
00541    }
00542 
00543    return ret;
00544 }
00545 
00546 int ast_module_reload(const char *name)
00547 {
00548    struct ast_module *cur;
00549    int res = 0; /* return value. 0 = not found, others, see below */
00550    int i;
00551 
00552    if (ast_mutex_trylock(&reloadlock)) {
00553       ast_verbose("The previous reload command didn't finish yet\n");
00554       return -1;  /* reload already in progress */
00555    }
00556    ast_lastreloadtime = time(NULL);
00557 
00558    /* Call "predefined" reload here first */
00559    for (i = 0; reload_classes[i].name; i++) {
00560       if (!name || !strcasecmp(name, reload_classes[i].name)) {
00561          reload_classes[i].reload_fn();   /* XXX should check error ? */
00562          res = 2; /* found and reloaded */
00563       }
00564    }
00565 
00566    if (name && res) {
00567       ast_mutex_unlock(&reloadlock);
00568       return res;
00569    }
00570 
00571    AST_LIST_LOCK(&module_list);
00572    AST_LIST_TRAVERSE(&module_list, cur, entry) {
00573       const struct ast_module_info *info = cur->info;
00574 
00575       if (name && resource_name_match(name, cur->resource))
00576          continue;
00577 
00578       if (!(cur->flags.running || cur->flags.declined))
00579          continue;
00580 
00581       if (!info->reload) { /* cannot be reloaded */
00582          if (res < 1)   /* store result if possible */
00583             res = 1; /* 1 = no reload() method */
00584          continue;
00585       }
00586 
00587       res = 2;
00588       if (option_verbose > 2)
00589          ast_verbose(VERBOSE_PREFIX_3 "Reloading module '%s' (%s)\n", cur->resource, info->description);
00590       info->reload();
00591    }
00592    AST_LIST_UNLOCK(&module_list);
00593 
00594    ast_mutex_unlock(&reloadlock);
00595 
00596    return res;
00597 }
00598 
00599 static unsigned int inspect_module(const struct ast_module *mod)
00600 {
00601    if (!mod->info->description) {
00602       ast_log(LOG_WARNING, "Module '%s' does not provide a description.\n", mod->resource);
00603       return 1;
00604    }
00605 
00606    if (!mod->info->key) {
00607       ast_log(LOG_WARNING, "Module '%s' does not provide a license key.\n", mod->resource);
00608       return 1;
00609    }
00610 
00611    if (verify_key((unsigned char *) mod->info->key)) {
00612       ast_log(LOG_WARNING, "Module '%s' did not provide a valid license key.\n", mod->resource);
00613       return 1;
00614    }
00615 
00616    return 0;
00617 }
00618 
00619 static enum ast_module_load_result load_resource(const char *resource_name, unsigned int global_symbols_only)
00620 {
00621    struct ast_module *mod;
00622    enum ast_module_load_result res = AST_MODULE_LOAD_SUCCESS;
00623    char tmp[256];
00624 
00625    if ((mod = find_resource(resource_name, 0))) {
00626       if (mod->flags.running) {
00627          ast_log(LOG_WARNING, "Module '%s' already exists.\n", resource_name);
00628          return AST_MODULE_LOAD_DECLINE;
00629       }
00630       if (global_symbols_only && !ast_test_flag(mod->info, AST_MODFLAG_GLOBAL_SYMBOLS))
00631          return AST_MODULE_LOAD_SKIP;
00632    } else {
00633 #if LOADABLE_MODULES
00634       if (!(mod = load_dynamic_module(resource_name, global_symbols_only))) {
00635          /* don't generate a warning message during load_modules() */
00636          if (!global_symbols_only) {
00637             ast_log(LOG_WARNING, "Module '%s' could not be loaded.\n", resource_name);
00638             return AST_MODULE_LOAD_DECLINE;
00639          } else {
00640             return AST_MODULE_LOAD_SKIP;
00641          }
00642       }
00643 #else
00644       ast_log(LOG_WARNING, "Module '%s' could not be loaded.\n", resource_name);
00645       return AST_MODULE_LOAD_DECLINE;
00646 #endif
00647    }
00648 
00649    if (inspect_module(mod)) {
00650       ast_log(LOG_WARNING, "Module '%s' could not be loaded.\n", resource_name);
00651 #if LOADABLE_MODULES
00652       unload_dynamic_module(mod);
00653 #endif
00654       return AST_MODULE_LOAD_DECLINE;
00655    }
00656 
00657    mod->flags.declined = 0;
00658 
00659    if (mod->info->load)
00660       res = mod->info->load();
00661 
00662    switch (res) {
00663    case AST_MODULE_LOAD_SUCCESS:
00664       if (!ast_fully_booted) {
00665          if (option_verbose)
00666             ast_verbose("%s => (%s)\n", resource_name, term_color(tmp, mod->info->description, COLOR_BROWN, COLOR_BLACK, sizeof(tmp)));
00667          if (ast_opt_console && !option_verbose)
00668             ast_verbose( ".");
00669       } else {
00670          if (option_verbose)
00671             ast_verbose(VERBOSE_PREFIX_1 "Loaded %s => (%s)\n", resource_name, mod->info->description);
00672       }
00673 
00674       mod->flags.running = 1;
00675 
00676       ast_update_use_count();
00677       break;
00678    case AST_MODULE_LOAD_DECLINE:
00679       mod->flags.declined = 1;
00680       break;
00681    case AST_MODULE_LOAD_FAILURE:
00682       break;
00683    case AST_MODULE_LOAD_SKIP:
00684       /* modules should never return this value */
00685       break;
00686    }
00687 
00688    return res;
00689 }
00690 
00691 int ast_load_resource(const char *resource_name)
00692 {
00693        AST_LIST_LOCK(&module_list);
00694        load_resource(resource_name, 0);
00695        AST_LIST_UNLOCK(&module_list);
00696 
00697        return 0;
00698 }
00699 
00700 struct load_order_entry {
00701    char *resource;
00702    AST_LIST_ENTRY(load_order_entry) entry;
00703 };
00704 
00705 AST_LIST_HEAD_NOLOCK(load_order, load_order_entry);
00706 
00707 static struct load_order_entry *add_to_load_order(const char *resource, struct load_order *load_order)
00708 {
00709    struct load_order_entry *order;
00710 
00711    AST_LIST_TRAVERSE(load_order, order, entry) {
00712       if (!resource_name_match(order->resource, resource))
00713          return NULL;
00714    }
00715 
00716    if (!(order = ast_calloc(1, sizeof(*order))))
00717       return NULL;
00718 
00719    order->resource = ast_strdup(resource);
00720    AST_LIST_INSERT_TAIL(load_order, order, entry);
00721 
00722    return order;
00723 }
00724 
00725 int load_modules(unsigned int preload_only)
00726 {
00727    struct ast_config *cfg;
00728    struct ast_module *mod;
00729    struct load_order_entry *order;
00730    struct ast_variable *v;
00731    unsigned int load_count;
00732    struct load_order load_order;
00733    int res = 0;
00734 #if LOADABLE_MODULES
00735    struct dirent *dirent;
00736    DIR *dir;
00737 #endif
00738 
00739    /* all embedded modules have registered themselves by now */
00740    embedding = 0;
00741 
00742    if (option_verbose)
00743       ast_verbose("Asterisk Dynamic Loader Starting:\n");
00744 
00745    AST_LIST_HEAD_INIT_NOLOCK(&load_order);
00746 
00747    AST_LIST_LOCK(&module_list);
00748 
00749    if (!(cfg = ast_config_load(AST_MODULE_CONFIG))) {
00750       ast_log(LOG_WARNING, "No '%s' found, no modules will be loaded.\n", AST_MODULE_CONFIG);
00751       goto done;
00752    }
00753 
00754    /* first, find all the modules we have been explicitly requested to load */
00755    for (v = ast_variable_browse(cfg, "modules"); v; v = v->next) {
00756       if (!strcasecmp(v->name, preload_only ? "preload" : "load"))
00757          add_to_load_order(v->value, &load_order);
00758    }
00759 
00760    /* check if 'autoload' is on */
00761    if (!preload_only && ast_true(ast_variable_retrieve(cfg, "modules", "autoload"))) {
00762       /* if so, first add all the embedded modules that are not already running to the load order */
00763       AST_LIST_TRAVERSE(&module_list, mod, entry) {
00764          /* if it's not embedded, skip it */
00765          if (mod->lib)
00766             continue;
00767 
00768          if (mod->flags.running)
00769             continue;
00770 
00771          order = add_to_load_order(mod->resource, &load_order);
00772       }
00773 
00774 #if LOADABLE_MODULES
00775       /* if we are allowed to load dynamic modules, scan the directory for
00776          for all available modules and add them as well */
00777       if ((dir  = opendir(ast_config_AST_MODULE_DIR))) {
00778          while ((dirent = readdir(dir))) {
00779             int ld = strlen(dirent->d_name);
00780 
00781             /* Must end in .so to load it.  */
00782 
00783             if (ld < 4)
00784                continue;
00785 
00786             if (strcasecmp(dirent->d_name + ld - 3, ".so"))
00787                continue;
00788 
00789             /* if there is already a module by this name in the module_list,
00790                skip this file */
00791             if (find_resource(dirent->d_name, 0))
00792                continue;
00793 
00794             add_to_load_order(dirent->d_name, &load_order);
00795          }
00796 
00797          closedir(dir);
00798       } else {
00799          if (!ast_opt_quiet)
00800             ast_log(LOG_WARNING, "Unable to open modules directory '%s'.\n",
00801                ast_config_AST_MODULE_DIR);
00802       }
00803 #endif
00804    }
00805 
00806    /* now scan the config for any modules we are prohibited from loading and
00807       remove them from the load order */
00808    for (v = ast_variable_browse(cfg, "modules"); v; v = v->next) {
00809       if (strcasecmp(v->name, "noload"))
00810          continue;
00811 
00812       AST_LIST_TRAVERSE_SAFE_BEGIN(&load_order, order, entry) {
00813          if (!resource_name_match(order->resource, v->value)) {
00814             AST_LIST_REMOVE_CURRENT(&load_order, entry);
00815             free(order->resource);
00816             free(order);
00817          }
00818       }
00819       AST_LIST_TRAVERSE_SAFE_END;
00820    }
00821 
00822    /* we are done with the config now, all the information we need is in the
00823       load_order list */
00824    ast_config_destroy(cfg);
00825 
00826    load_count = 0;
00827    AST_LIST_TRAVERSE(&load_order, order, entry)
00828       load_count++;
00829 
00830    if (load_count)
00831       ast_log(LOG_NOTICE, "%d modules will be loaded.\n", load_count);
00832 
00833    /* first, load only modules that provide global symbols */
00834    AST_LIST_TRAVERSE_SAFE_BEGIN(&load_order, order, entry) {
00835       switch (load_resource(order->resource, 1)) {
00836       case AST_MODULE_LOAD_SUCCESS:
00837       case AST_MODULE_LOAD_DECLINE:
00838          AST_LIST_REMOVE_CURRENT(&load_order, entry);
00839          free(order->resource);
00840          free(order);
00841          break;
00842       case AST_MODULE_LOAD_FAILURE:
00843          res = -1;
00844          goto done;
00845       case AST_MODULE_LOAD_SKIP:
00846          /* try again later */
00847          break;
00848       }
00849    }
00850    AST_LIST_TRAVERSE_SAFE_END;
00851 
00852    /* now load everything else */
00853    AST_LIST_TRAVERSE_SAFE_BEGIN(&load_order, order, entry) {
00854       switch (load_resource(order->resource, 0)) {
00855       case AST_MODULE_LOAD_SUCCESS:
00856       case AST_MODULE_LOAD_DECLINE:
00857          AST_LIST_REMOVE_CURRENT(&load_order, entry);
00858          free(order->resource);
00859          free(order);
00860          break;
00861       case AST_MODULE_LOAD_FAILURE:
00862          res = -1;
00863          goto done;
00864       case AST_MODULE_LOAD_SKIP:
00865          /* should not happen */
00866          break;
00867       }
00868    }
00869    AST_LIST_TRAVERSE_SAFE_END;
00870 
00871 done:
00872    while ((order = AST_LIST_REMOVE_HEAD(&load_order, entry))) {
00873       free(order->resource);
00874       free(order);
00875    }
00876 
00877    AST_LIST_UNLOCK(&module_list);
00878 
00879    return res;
00880 }
00881 
00882 void ast_update_use_count(void)
00883 {
00884    /* Notify any module monitors that the use count for a
00885       resource has changed */
00886    struct loadupdate *m;
00887 
00888    AST_LIST_LOCK(&module_list);
00889    AST_LIST_TRAVERSE(&updaters, m, entry)
00890       m->updater();
00891    AST_LIST_UNLOCK(&module_list);
00892 }
00893 
00894 int ast_update_module_list(int (*modentry)(const char *module, const char *description, int usecnt, const char *like),
00895             const char *like)
00896 {
00897    struct ast_module *cur;
00898    int unlock = -1;
00899    int total_mod_loaded = 0;
00900 
00901    if (AST_LIST_TRYLOCK(&module_list))
00902       unlock = 0;
00903 
00904    AST_LIST_TRAVERSE(&module_list, cur, entry) {
00905       total_mod_loaded += modentry(cur->resource, cur->info->description, cur->usecount, like);
00906    }
00907 
00908    if (unlock)
00909       AST_LIST_UNLOCK(&module_list);
00910 
00911    return total_mod_loaded;
00912 }
00913 
00914 int ast_module_check(char *name)
00915 {
00916    struct ast_module *cur;
00917    int unlock = -1;
00918    int res = 0;
00919 
00920    if (ast_strlen_zero(name))
00921       return 0;   /* FALSE */
00922 
00923    if (ast_mutex_trylock(&module_list.lock))
00924       unlock = 0;
00925    AST_LIST_TRAVERSE(&module_list, cur, entry)
00926       if (!res && !strcasecmp(name, cur->resource))
00927          res = 1;
00928    if (unlock)
00929       AST_LIST_UNLOCK(&module_list);
00930    return res;
00931 }
00932 
00933 int ast_loader_register(int (*v)(void))
00934 {
00935    struct loadupdate *tmp;
00936 
00937    if (!(tmp = ast_malloc(sizeof(*tmp))))
00938       return -1;
00939 
00940    tmp->updater = v;
00941    AST_LIST_LOCK(&module_list);
00942    AST_LIST_INSERT_HEAD(&updaters, tmp, entry);
00943    AST_LIST_UNLOCK(&module_list);
00944 
00945    return 0;
00946 }
00947 
00948 int ast_loader_unregister(int (*v)(void))
00949 {
00950    struct loadupdate *cur;
00951 
00952    AST_LIST_LOCK(&module_list);
00953    AST_LIST_TRAVERSE_SAFE_BEGIN(&updaters, cur, entry) {
00954       if (cur->updater == v)  {
00955          AST_LIST_REMOVE_CURRENT(&updaters, entry);
00956          break;
00957       }
00958    }
00959    AST_LIST_TRAVERSE_SAFE_END;
00960    AST_LIST_UNLOCK(&module_list);
00961 
00962    return cur ? 0 : -1;
00963 }
00964 
00965 struct ast_module *ast_module_ref(struct ast_module *mod)
00966 {
00967    ast_atomic_fetchadd_int(&mod->usecount, +1);
00968    ast_update_use_count();
00969 
00970    return mod;
00971 }
00972 
00973 void ast_module_unref(struct ast_module *mod)
00974 {
00975    ast_atomic_fetchadd_int(&mod->usecount, -1);
00976    ast_update_use_count();
00977 }

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