loader.c

   1 /*
   2  * Asterisk -- A telephony toolkit for Linux.
   3  *
   4  * Module Loader
   5  *
   6  * Copyright (C) 1999, Mark Spencer
   7  *
   8  * Mark Spencer <markster@linux-support.net>
   9  *
  10  * This program is free software, distributed under the terms of
  11  * the GNU General Public License
  12  */
  13
  14 #include <stdio.h>
  15 #include <dirent.h>
  16 #include <unistd.h>
  17 #include <stdlib.h>
  18 #include <string.h>
  19 #include <asterisk/module.h>
  20 #include <asterisk/options.h>
  21 #include <asterisk/config.h>
  22 #include <asterisk/logger.h>
  23 #include <asterisk/channel.h>
  24 #include <asterisk/term.h>
  25 #include <asterisk/manager.h>
  26 #include <asterisk/enum.h>
  27 #include <asterisk/rtp.h>
  28 #ifdef __APPLE__
  29 #include <asterisk/dlfcn-compat.h>
  30 #else
  31 #include <dlfcn.h>
  32 #endif
  33 #include <asterisk/md5.h>
  34 #include <pthread.h>
  35 #include "asterisk.h"
  36 #include "astconf.h"
  37
  38 #ifndef RTLD_NOW
  39 #define RTLD_NOW 0
  40 #endif
  41
  42 static char expected_key[] =
  43 { 0x8e, 0x93, 0x22, 0x83, 0xf5, 0xc3, 0xc0, 0x75,
  44   0xff, 0x8b, 0xa9, 0xbe, 0x7c, 0x43, 0x74, 0x63 };
  45
  46 struct module {
  47         int (*load_module)(void);
  48         int (*unload_module)(void);
  49         int (*usecount)(void);
  50         char *(*description)(void);
  51         char *(*key)(void);
  52         int (*reload)(void);
  53         void *lib;
  54         char resource[256];
  55         struct module *next;
  56 };
  57
  58 static int printdigest(unsigned char *d)
  59 {
  60         int x;
  61         char buf[256];
  62         char buf2[16];
  63         snprintf(buf, sizeof(buf), "Unexpected signature:");
  64         for (x=0;x<16;x++) {
  65                 snprintf(buf2, sizeof(buf2), " %02x", *(d++));
  66                 strcat(buf, buf2);
  67         }
  68         strcat(buf, "\n");
  69         ast_log(LOG_DEBUG, buf);
  70         return 0;
  71 }
  72
  73 static int key_matches(char *key1, char *key2)
  74 {
  75         int match = 1;
  76         int x;
  77         for (x=0;x<16;x++) {
  78                 match &= (key1[x] == key2[x]);
  79         }
  80         return match;
  81 }
  82
  83 static int verify_key(char *key)
  84 {
  85         struct MD5Context c;
  86         char digest[16];
  87         MD5Init(&c);
  88         MD5Update(&c, key, strlen(key));
  89         MD5Final(digest, &c);
  90         if (key_matches(expected_key, digest))
  91                 return 0;
  92         printdigest(digest);
  93         return -1;
  94 }
  95
  96 static struct loadupdate {
  97         int (*updater)(void);
  98         struct loadupdate *next;
  99 } *updaters = NULL;
 100
 101 static ast_mutex_t modlock = AST_MUTEX_INITIALIZER;
 102 static ast_mutex_t reloadlock = AST_MUTEX_INITIALIZER;
 103
 104 static struct module *module_list=NULL;
 105
 106 int ast_unload_resource(char *resource_name, int force)
 107 {
 108         struct module *m, *ml = NULL;
 109         int res = -1;
 110         if (ast_mutex_lock(&modlock))
 111                 ast_log(LOG_WARNING, "Failed to lock\n");
 112         m = module_list;
 113         while(m) {
 114                 if (!strcasecmp(m->resource, resource_name)) {
 115                         if ((res = m->usecount()) > 0)  {
 116                                 if (force)
 117                                         ast_log(LOG_WARNING, "Warning:  Forcing removal of module %s with use count %d\n", resource_name, res);
 118                                 else {
 119                                         ast_log(LOG_WARNING, "Soft unload failed, '%s' has use count %d\n", resource_name, res);
 120                                         ast_mutex_unlock(&modlock);
 121                                         return -1;
 122                                 }
 123                         }
 124                         res = m->unload_module();
 125                         if (res) {
 126                                 ast_log(LOG_WARNING, "Firm unload failed for %s\n", resource_name);
 127                                 if (force <= AST_FORCE_FIRM) {
 128                                         ast_mutex_unlock(&modlock);
 129                                         return -1;
 130                                 } else
 131                                         ast_log(LOG_WARNING, "** Dangerous **: Unloading resource anyway, at user request\n");
 132                         }
 133                         if (ml)
 134                                 ml->next = m->next;
 135                         else
 136                                 module_list = m->next;
 137                         dlclose(m->lib);
 138                         free(m);
 139                         break;
 140                 }
 141                 ml = m;
 142                 m = m->next;
 143         }
 144         ast_mutex_unlock(&modlock);
 145         ast_update_use_count();
 146         return res;
 147 }
 148
 149 void ast_module_reload(void)
 150 {
 151         struct module *m;
 152
 153         /* We'll do the logger and manager the favor of calling its reload here first */
 154
 155         if (ast_mutex_trylock(&reloadlock)) {
 156                 ast_verbose("The previous reload command didn't finish yet\n");
 157                 return;
 158         }
 159         reload_manager();
 160         ast_enum_reload();
 161         ast_rtp_reload();
 162         time(&ast_lastreloadtime);
 163
 164         ast_mutex_lock(&modlock);
 165         m = module_list;
 166         while(m) {
 167                 if (m->reload) {
 168                         if (option_verbose > 2)
 169                                 ast_verbose(VERBOSE_PREFIX_3 "Reloading module '%s' (%s)\n", m->resource, m->description());
 170                         m->reload();
 171                 }
 172                 m = m->next;
 173         }
 174         ast_mutex_unlock(&modlock);
 175         ast_mutex_unlock(&reloadlock);
 176 }
 177
 178 int ast_load_resource(char *resource_name)
 179 {
 180         static char fn[256];
 181         int errors=0;
 182         int res;
 183         struct module *m;
 184         int flags=RTLD_NOW;
 185 #ifdef RTLD_GLOBAL
 186         char *val;
 187 #endif
 188         char *key;
 189         int o;
 190         struct ast_config *cfg;
 191         char tmp[80];
 192         /* Keep the module file parsing silent */
 193         o = option_verbose;
 194         if (strncasecmp(resource_name, "res_", 4)) {
 195                 option_verbose = 0;
 196                 cfg = ast_load(AST_MODULE_CONFIG);
 197                 option_verbose = o;
 198                 if (cfg) {
 199 #ifdef RTLD_GLOBAL
 200                         if ((val = ast_variable_retrieve(cfg, "global", resource_name))
 201                                         && ast_true(val))
 202                                 flags |= RTLD_GLOBAL;
 203 #endif
 204                         ast_destroy(cfg);
 205                 }
 206         } else {
 207                 /* Resource modules are always loaded global and lazy */
 208 #ifdef RTLD_GLOBAL
 209                 flags = (RTLD_GLOBAL | RTLD_LAZY);
 210 #else
 211                 flags = RTLD_LAZY;
 212 #endif
 213         }
 214
 215         if (ast_mutex_lock(&modlock))
 216                 ast_log(LOG_WARNING, "Failed to lock\n");
 217         m = module_list;
 218         while(m) {
 219                 if (!strcasecmp(m->resource, resource_name)) {
 220                         ast_log(LOG_WARNING, "Module '%s' already exists\n", resource_name);
 221                         ast_mutex_unlock(&modlock);
 222                         return -1;
 223                 }
 224                 m = m->next;
 225         }
 226         m = malloc(sizeof(struct module));
 227         if (!m) {
 228                 ast_log(LOG_WARNING, "Out of memory\n");
 229                 ast_mutex_unlock(&modlock);
 230                 return -1;
 231         }
 232         strncpy(m->resource, resource_name, sizeof(m->resource)-1);
 233         if (resource_name[0] == '/') {
 234                 strncpy(fn, resource_name, sizeof(fn)-1);
 235         } else {
 236                 snprintf(fn, sizeof(fn), "%s/%s", (char *)ast_config_AST_MODULE_DIR, resource_name);
 237         }
 238         m->lib = dlopen(fn, flags);
 239         if (!m->lib) {
 240                 ast_log(LOG_WARNING, "%s\n", dlerror());
 241                 free(m);
 242                 ast_mutex_unlock(&modlock);
 243                 return -1;
 244         }
 245         m->load_module = dlsym(m->lib, "load_module");
 246         if (m->load_module == NULL)
 247                 m->load_module = dlsym(m->lib, "_load_module");
 248         if (!m->load_module) {
 249                 ast_log(LOG_WARNING, "No load_module in module %s\n", fn);
 250                 errors++;
 251         }
 252         m->unload_module = dlsym(m->lib, "unload_module");
 253         if (m->unload_module == NULL)
 254                 m->unload_module = dlsym(m->lib, "_unload_module");
 255         if (!m->unload_module) {
 256                 ast_log(LOG_WARNING, "No unload_module in module %s\n", fn);
 257                 errors++;
 258         }
 259         m->usecount = dlsym(m->lib, "usecount");
 260         if (m->usecount == NULL)
 261                 m->usecount = dlsym(m->lib, "_usecount");
 262         if (!m->usecount) {
 263                 ast_log(LOG_WARNING, "No usecount in module %s\n", fn);
 264                 errors++;
 265         }
 266         m->description = dlsym(m->lib, "description");
 267         if (m->description == NULL)
 268                 m->description = dlsym(m->lib, "_description");
 269         if (!m->description) {
 270                 ast_log(LOG_WARNING, "No description in module %s\n", fn);
 271                 errors++;
 272         }
 273         m->key = dlsym(m->lib, "key");
 274         if (m->key == NULL)
 275                 m->key = dlsym(m->lib, "_key");
 276         if (!m->key) {
 277                 ast_log(LOG_WARNING, "No key routine in module %s\n", fn);
 278                 errors++;
 279         }
 280         m->reload = dlsym(m->lib, "reload");
 281         if (m->reload == NULL)
 282                 m->reload = dlsym(m->lib, "_reload");
 283         if (m->key && !(key = m->key())) {
 284                 ast_log(LOG_WARNING, "Key routine returned NULL in module %s\n", fn);
 285                 errors++;
 286         } else
 287                 key = NULL;
 288         if (key && verify_key(key)) {
 289                 ast_log(LOG_WARNING, "Unexpected key returned by module %s\n", fn);
 290                 errors++;
 291         }
 292         if (errors) {
 293                 ast_log(LOG_WARNING, "%d error(s) loading module %s, aborted\n", errors, fn);
 294                 dlclose(m->lib);
 295                 free(m);
 296                 ast_mutex_unlock(&modlock);
 297                 return -1;
 298         }
 299         if (!fully_booted) {
 300                 if (option_verbose)
 301                         ast_verbose( " => (%s)\n", term_color(tmp, m->description(), COLOR_BROWN, COLOR_BLACK, sizeof(tmp)));
 302                 if (option_console && !option_verbose)
 303                         ast_verbose( ".");
 304         } else {
 305                 if (option_verbose)
 306                         ast_verbose(VERBOSE_PREFIX_1 "Loaded %s => (%s)\n", fn, m->description());
 307         }
 308         m->next = module_list;
 309
 310         module_list = m;
 311         ast_mutex_unlock(&modlock);
 312         if ((res = m->load_module())) {
 313                 ast_log(LOG_WARNING, "%s: load_module failed, returning %d\n", m->resource, res);
 314                 ast_unload_resource(resource_name, 0);
 315                 return -1;
 316         }
 317         ast_update_use_count();
 318         return 0;
 319 }
 320
 321 static int ast_resource_exists(char *resource)
 322 {
 323         struct module *m;
 324         if (ast_mutex_lock(&modlock))
 325                 ast_log(LOG_WARNING, "Failed to lock\n");
 326         m = module_list;
 327         while(m) {
 328                 if (!strcasecmp(resource, m->resource))
 329                         break;
 330                 m = m->next;
 331         }
 332         ast_mutex_unlock(&modlock);
 333         if (m)
 334                 return -1;
 335         else
 336                 return 0;
 337 }
 338
 339 int load_modules()
 340 {
 341         struct ast_config *cfg;
 342         struct ast_variable *v;
 343         char tmp[80];
 344         if (option_verbose)
 345                 ast_verbose( "Asterisk Dynamic Loader Starting:\n");
 346         cfg = ast_load(AST_MODULE_CONFIG);
 347         if (cfg) {
 348                 /* Load explicitly defined modules */
 349                 v = ast_variable_browse(cfg, "modules");
 350                 while(v) {
 351                         if (!strcasecmp(v->name, "load")) {
 352                                 if (option_debug && !option_verbose)
 353                                         ast_log(LOG_DEBUG, "Loading module %s\n", v->value);
 354                                 if (option_verbose) {
 355                                         ast_verbose( VERBOSE_PREFIX_1 "[%s]", term_color(tmp, v->value, COLOR_BRWHITE, 0, sizeof(tmp)));
 356                                         fflush(stdout);
 357                                 }
 358                                 if (ast_load_resource(v->value)) {
 359                                         ast_log(LOG_WARNING, "Loading module %s failed!\n", v->value);
 360                                         if (cfg)
 361                                                 ast_destroy(cfg);
 362                                         return -1;
 363                                 }
 364                         }
 365                         v=v->next;
 366                 }
 367         }
 368         if (!cfg || ast_true(ast_variable_retrieve(cfg, "modules", "autoload"))) {
 369                 /* Load all modules */
 370                 DIR *mods;
 371                 struct dirent *d;
 372                 int x;
 373                 /* Make two passes.  First, load any resource modules, then load the others. */
 374                 for (x=0;x<2;x++) {
 375                         mods = opendir((char *)ast_config_AST_MODULE_DIR);
 376                         if (mods) {
 377                                 while((d = readdir(mods))) {
 378                                         /* Must end in .so to load it.  */
 379                                         if ((strlen(d->d_name) > 3) && (x || !strncasecmp(d->d_name, "res_", 4)) &&
 380                                             !strcasecmp(d->d_name + strlen(d->d_name) - 3, ".so") &&
 381                                                 !ast_resource_exists(d->d_name)) {
 382                                                 /* It's a shared library -- Just be sure we're allowed to load it -- kinda
 383                                                    an inefficient way to do it, but oh well. */
 384                                                 if (cfg) {
 385                                                         v = ast_variable_browse(cfg, "modules");
 386                                                         while(v) {
 387                                                                 if (!strcasecmp(v->name, "noload") &&
 388                                                                     !strcasecmp(v->value, d->d_name))
 389                                                                         break;
 390                                                                 v = v->next;
 391                                                         }
 392                                                         if (v) {
 393                                                                 if (option_verbose) {
 394                                                                         ast_verbose( VERBOSE_PREFIX_1 "[skipping %s]\n", d->d_name);
 395                                                                         fflush(stdout);
 396                                                                 }
 397                                                                 continue;
 398                                                         }
 399
 400                                                 }
 401                                             if (option_debug && !option_verbose)
 402                                                         ast_log(LOG_DEBUG, "Loading module %s\n", d->d_name);
 403                                                 if (option_verbose) {
 404                                                         ast_verbose( VERBOSE_PREFIX_1 "[%s]", term_color(tmp, d->d_name, COLOR_BRWHITE, 0, sizeof(tmp)));
 405                                                         fflush(stdout);
 406                                                 }
 407                                                 if (ast_load_resource(d->d_name)) {
 408                                                         ast_log(LOG_WARNING, "Loading module %s failed!\n", d->d_name);
 409                                                         if (cfg)
 410                                                                 ast_destroy(cfg);
 411                                                         return -1;
 412                                                 }
 413                                         }
 414                                 }
 415                                 closedir(mods);
 416                         } else {
 417                                 if (!option_quiet)
 418                                         ast_log(LOG_WARNING, "Unable to open modules directory %s.\n", (char *)ast_config_AST_MODULE_DIR);
 419                         }
 420                 }
 421         }
 422         ast_destroy(cfg);
 423         return 0;
 424 }
 425
 426 void ast_update_use_count(void)
 427 {
 428         /* Notify any module monitors that the use count for a
 429            resource has changed */
 430         struct loadupdate *m;
 431         if (ast_mutex_lock(&modlock))
 432                 ast_log(LOG_WARNING, "Failed to lock\n");
 433         m = updaters;
 434         while(m) {
 435                 m->updater();
 436                 m = m->next;
 437         }
 438         ast_mutex_unlock(&modlock);
 439
 440 }
 441
 442 int ast_update_module_list(int (*modentry)(char *module, char *description, int usecnt))
 443 {
 444         struct module *m;
 445         int unlock = -1;
 446         if (ast_mutex_trylock(&modlock))
 447                 unlock = 0;
 448         m = module_list;
 449         while(m) {
 450                 modentry(m->resource, m->description(), m->usecount());
 451                 m = m->next;
 452         }
 453         if (unlock)
 454                 ast_mutex_unlock(&modlock);
 455         return 0;
 456 }
 457
 458 int ast_loader_register(int (*v)(void))
 459 {
 460         struct loadupdate *tmp;
 461         /* XXX Should be more flexible here, taking > 1 verboser XXX */
 462         if ((tmp = malloc(sizeof (struct loadupdate)))) {
 463                 tmp->updater = v;
 464                 if (ast_mutex_lock(&modlock))
 465                         ast_log(LOG_WARNING, "Failed to lock\n");
 466                 tmp->next = updaters;
 467                 updaters = tmp;
 468                 ast_mutex_unlock(&modlock);
 469                 return 0;
 470         }
 471         return -1;
 472 }
 473
 474 int ast_loader_unregister(int (*v)(void))
 475 {
 476         int res = -1;
 477         struct loadupdate *tmp, *tmpl=NULL;
 478         if (ast_mutex_lock(&modlock))
 479                 ast_log(LOG_WARNING, "Failed to lock\n");
 480         tmp = updaters;
 481         while(tmp) {
 482                 if (tmp->updater == v)  {
 483                         if (tmpl)
 484                                 tmpl->next = tmp->next;
 485                         else
 486                                 updaters = tmp->next;
 487                         break;
 488                 }
 489                 tmpl = tmp;
 490                 tmp = tmp->next;
 491         }
 492         if (tmp)
 493                 res = 0;
 494         ast_mutex_unlock(&modlock);
 495         return res;
 496 }