loader.c

   1 /*
   2  * Asterisk -- A telephony toolkit for Linux.
   3  *
   4  * Module Loader
   5  *
   6  * Copyright (C) 1999-2004, Digium, Inc.
   7  *
   8  * Mark Spencer <markster@digium.com>
   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/config_pvt.h>
  23 #include <asterisk/logger.h>
  24 #include <asterisk/channel.h>
  25 #include <asterisk/term.h>
  26 #include <asterisk/manager.h>
  27 #include <asterisk/enum.h>
  28 #include <asterisk/rtp.h>
  29 #include <asterisk/lock.h>
  30 #ifdef __APPLE__
  31 #include <asterisk/dlfcn-compat.h>
  32 #else
  33 #include <dlfcn.h>
  34 #endif
  35 #include <asterisk/md5.h>
  36 #include "asterisk.h"
  37 #include "astconf.h"
  38
  39 #ifndef RTLD_NOW
  40 #define RTLD_NOW 0
  41 #endif
  42
  43 static char expected_key[] =
  44 { 0x8e, 0x93, 0x22, 0x83, 0xf5, 0xc3, 0xc0, 0x75,
  45   0xff, 0x8b, 0xa9, 0xbe, 0x7c, 0x43, 0x74, 0x63 };
  46
  47 struct module {
  48         int (*load_module)(void);
  49         int (*unload_module)(void);
  50         int (*usecount)(void);
  51         char *(*description)(void);
  52         char *(*key)(void);
  53         int (*reload)(void);
  54         void *lib;
  55         char resource[256];
  56         struct module *next;
  57 };
  58
  59 static int printdigest(unsigned char *d)
  60 {
  61         int x;
  62         char buf[256];
  63         char buf2[16];
  64         snprintf(buf, sizeof(buf), "Unexpected signature:");
  65         for (x=0;x<16;x++) {
  66                 snprintf(buf2, sizeof(buf2), " %02x", *(d++));
  67                 strcat(buf, buf2);
  68         }
  69         strcat(buf, "\n");
  70         ast_log(LOG_DEBUG, buf);
  71         return 0;
  72 }
  73
  74 static int key_matches(char *key1, char *key2)
  75 {
  76         int match = 1;
  77         int x;
  78         for (x=0;x<16;x++) {
  79                 match &= (key1[x] == key2[x]);
  80         }
  81         return match;
  82 }
  83
  84 static int verify_key(char *key)
  85 {
  86         struct MD5Context c;
  87         char digest[16];
  88         MD5Init(&c);
  89         MD5Update(&c, key, strlen(key));
  90         MD5Final(digest, &c);
  91         if (key_matches(expected_key, digest))
  92                 return 0;
  93         printdigest(digest);
  94         return -1;
  95 }
  96
  97 static struct loadupdate {
  98         int (*updater)(void);
  99         struct loadupdate *next;
 100 } *updaters = NULL;
 101
 102 AST_MUTEX_DEFINE_STATIC(modlock);
 103 AST_MUTEX_DEFINE_STATIC(reloadlock);
 104
 105 static struct module *module_list=NULL;
 106
 107 int ast_unload_resource(char *resource_name, int force)
 108 {
 109         struct module *m, *ml = NULL;
 110         int res = -1;
 111         if (ast_mutex_lock(&modlock))
 112                 ast_log(LOG_WARNING, "Failed to lock\n");
 113         m = module_list;
 114         while(m) {
 115                 if (!strcasecmp(m->resource, resource_name)) {
 116                         if ((res = m->usecount()) > 0)  {
 117                                 if (force)
 118                                         ast_log(LOG_WARNING, "Warning:  Forcing removal of module %s with use count %d\n", resource_name, res);
 119                                 else {
 120                                         ast_log(LOG_WARNING, "Soft unload failed, '%s' has use count %d\n", resource_name, res);
 121                                         ast_mutex_unlock(&modlock);
 122                                         return -1;
 123                                 }
 124                         }
 125                         res = m->unload_module();
 126                         if (res) {
 127                                 ast_log(LOG_WARNING, "Firm unload failed for %s\n", resource_name);
 128                                 if (force <= AST_FORCE_FIRM) {
 129                                         ast_mutex_unlock(&modlock);
 130                                         return -1;
 131                                 } else
 132                                         ast_log(LOG_WARNING, "** Dangerous **: Unloading resource anyway, at user request\n");
 133                         }
 134                         if (ml)
 135                                 ml->next = m->next;
 136                         else
 137                                 module_list = m->next;
 138                         dlclose(m->lib);
 139                         free(m);
 140                         break;
 141                 }
 142                 ml = m;
 143                 m = m->next;
 144         }
 145         ast_mutex_unlock(&modlock);
 146         ast_update_use_count();
 147         return res;
 148 }
 149
 150 void ast_module_reload(const char *name)
 151 {
 152         struct module *m;
 153
 154         /* We'll do the logger and manager the favor of calling its reload here first */
 155
 156         if (ast_mutex_trylock(&reloadlock)) {
 157                 ast_verbose("The previous reload command didn't finish yet\n");
 158                 return;
 159         }
 160         if (!name || !strcasecmp(name, "astconfig"))
 161                 read_ast_cust_config();
 162         if (!name || !strcasecmp(name, "manager"))
 163                 reload_manager();
 164         if (!name || !strcasecmp(name, "enum"))
 165                 ast_enum_reload();
 166         if (!name || !strcasecmp(name, "rtp"))
 167                 ast_rtp_reload();
 168         time(&ast_lastreloadtime);
 169
 170         ast_mutex_lock(&modlock);
 171         m = module_list;
 172         while(m) {
 173                 if (!name || !strcasecmp(name, m->resource)) {
 174                         if (m->reload) {
 175                                 if (option_verbose > 2)
 176                                         ast_verbose(VERBOSE_PREFIX_3 "Reloading module '%s' (%s)\n", m->resource, m->description());
 177                                 m->reload();
 178                         }
 179                 }
 180                 m = m->next;
 181         }
 182         ast_mutex_unlock(&modlock);
 183         ast_mutex_unlock(&reloadlock);
 184 }
 185
 186 int ast_load_resource(char *resource_name)
 187 {
 188         static char fn[256];
 189         int errors=0;
 190         int res;
 191         struct module *m;
 192         int flags=RTLD_NOW;
 193 #ifdef RTLD_GLOBAL
 194         char *val;
 195 #endif
 196         char *key;
 197         int o;
 198         struct ast_config *cfg;
 199         char tmp[80];
 200         /* Keep the module file parsing silent */
 201         o = option_verbose;
 202         if (strncasecmp(resource_name, "res_", 4)) {
 203                 option_verbose = 0;
 204                 cfg = ast_load(AST_MODULE_CONFIG);
 205                 option_verbose = o;
 206                 if (cfg) {
 207 #ifdef RTLD_GLOBAL
 208                         if ((val = ast_variable_retrieve(cfg, "global", resource_name))
 209                                         && ast_true(val))
 210                                 flags |= RTLD_GLOBAL;
 211 #endif
 212                         ast_destroy(cfg);
 213                 }
 214         } else {
 215                 /* Resource modules are always loaded global and lazy */
 216 #ifdef RTLD_GLOBAL
 217                 flags = (RTLD_GLOBAL | RTLD_LAZY);
 218 #else
 219                 flags = RTLD_LAZY;
 220 #endif
 221         }
 222
 223         if (ast_mutex_lock(&modlock))
 224                 ast_log(LOG_WARNING, "Failed to lock\n");
 225         m = module_list;
 226         while(m) {
 227                 if (!strcasecmp(m->resource, resource_name)) {
 228                         ast_log(LOG_WARNING, "Module '%s' already exists\n", resource_name);
 229                         ast_mutex_unlock(&modlock);
 230                         return -1;
 231                 }
 232                 m = m->next;
 233         }
 234         m = malloc(sizeof(struct module));
 235         if (!m) {
 236                 ast_log(LOG_WARNING, "Out of memory\n");
 237                 ast_mutex_unlock(&modlock);
 238                 return -1;
 239         }
 240         strncpy(m->resource, resource_name, sizeof(m->resource)-1);
 241         if (resource_name[0] == '/') {
 242                 strncpy(fn, resource_name, sizeof(fn)-1);
 243         } else {
 244                 snprintf(fn, sizeof(fn), "%s/%s", (char *)ast_config_AST_MODULE_DIR, resource_name);
 245         }
 246         m->lib = dlopen(fn, flags);
 247         if (!m->lib) {
 248                 ast_log(LOG_WARNING, "%s\n", dlerror());
 249                 free(m);
 250                 ast_mutex_unlock(&modlock);
 251                 return -1;
 252         }
 253         m->load_module = dlsym(m->lib, "load_module");
 254         if (m->load_module == NULL)
 255                 m->load_module = dlsym(m->lib, "_load_module");
 256         if (!m->load_module) {
 257                 ast_log(LOG_WARNING, "No load_module in module %s\n", fn);
 258                 errors++;
 259         }
 260         m->unload_module = dlsym(m->lib, "unload_module");
 261         if (m->unload_module == NULL)
 262                 m->unload_module = dlsym(m->lib, "_unload_module");
 263         if (!m->unload_module) {
 264                 ast_log(LOG_WARNING, "No unload_module in module %s\n", fn);
 265                 errors++;
 266         }
 267         m->usecount = dlsym(m->lib, "usecount");
 268         if (m->usecount == NULL)
 269                 m->usecount = dlsym(m->lib, "_usecount");
 270         if (!m->usecount) {
 271                 ast_log(LOG_WARNING, "No usecount in module %s\n", fn);
 272                 errors++;
 273         }
 274         m->description = dlsym(m->lib, "description");
 275         if (m->description == NULL)
 276                 m->description = dlsym(m->lib, "_description");
 277         if (!m->description) {
 278                 ast_log(LOG_WARNING, "No description in module %s\n", fn);
 279                 errors++;
 280         }
 281         m->key = dlsym(m->lib, "key");
 282         if (m->key == NULL)
 283                 m->key = dlsym(m->lib, "_key");
 284         if (!m->key) {
 285                 ast_log(LOG_WARNING, "No key routine in module %s\n", fn);
 286                 errors++;
 287         }
 288         m->reload = dlsym(m->lib, "reload");
 289         if (m->reload == NULL)
 290                 m->reload = dlsym(m->lib, "_reload");
 291         if (!m->key || !(key = m->key())) {
 292                 ast_log(LOG_WARNING, "Key routine returned NULL in module %s\n", fn);
 293                 key = NULL;
 294                 errors++;
 295         }
 296         if (key && verify_key(key)) {
 297                 ast_log(LOG_WARNING, "Unexpected key returned by module %s\n", fn);
 298                 errors++;
 299         }
 300         if (errors) {
 301                 ast_log(LOG_WARNING, "%d error(s) loading module %s, aborted\n", errors, fn);
 302                 dlclose(m->lib);
 303                 free(m);
 304                 ast_mutex_unlock(&modlock);
 305                 return -1;
 306         }
 307         if (!fully_booted) {
 308                 if (option_verbose)
 309                         ast_verbose( " => (%s)\n", term_color(tmp, m->description(), COLOR_BROWN, COLOR_BLACK, sizeof(tmp)));
 310                 if (option_console && !option_verbose)
 311                         ast_verbose( ".");
 312         } else {
 313                 if (option_verbose)
 314                         ast_verbose(VERBOSE_PREFIX_1 "Loaded %s => (%s)\n", fn, m->description());
 315         }
 316
 317         // add module 'm' to end of module_list chain
 318         // so reload commands will be issued in same order modules were loaded
 319         m->next = NULL;
 320         if (module_list == NULL) {
 321                 // empty list so far, add at front
 322                 module_list = m;
 323         }
 324         else {
 325                 struct module *i;
 326                 // find end of chain, and add there
 327                 for (i = module_list; i->next; i = i->next)
 328                         ;
 329                 i->next = m;
 330         }
 331
 332         ast_mutex_unlock(&modlock);
 333         if ((res = m->load_module())) {
 334                 ast_log(LOG_WARNING, "%s: load_module failed, returning %d\n", m->resource, res);
 335                 ast_unload_resource(resource_name, 0);
 336                 return -1;
 337         }
 338         ast_update_use_count();
 339         return 0;
 340 }
 341
 342 static int ast_resource_exists(char *resource)
 343 {
 344         struct module *m;
 345         if (ast_mutex_lock(&modlock))
 346                 ast_log(LOG_WARNING, "Failed to lock\n");
 347         m = module_list;
 348         while(m) {
 349                 if (!strcasecmp(resource, m->resource))
 350                         break;
 351                 m = m->next;
 352         }
 353         ast_mutex_unlock(&modlock);
 354         if (m)
 355                 return -1;
 356         else
 357                 return 0;
 358 }
 359
 360 int load_modules()
 361 {
 362         struct ast_config *cfg;
 363         struct ast_variable *v;
 364         char tmp[80];
 365         if (option_verbose)
 366                 ast_verbose( "Asterisk Dynamic Loader Starting:\n");
 367         cfg = ast_load(AST_MODULE_CONFIG);
 368         if (cfg) {
 369                 /* Load explicitly defined modules */
 370                 v = ast_variable_browse(cfg, "modules");
 371                 while(v) {
 372                         if (!strcasecmp(v->name, "load")) {
 373                                 if (option_debug && !option_verbose)
 374                                         ast_log(LOG_DEBUG, "Loading module %s\n", v->value);
 375                                 if (option_verbose) {
 376                                         ast_verbose( VERBOSE_PREFIX_1 "[%s]", term_color(tmp, v->value, COLOR_BRWHITE, 0, sizeof(tmp)));
 377                                         fflush(stdout);
 378                                 }
 379                                 if (ast_load_resource(v->value)) {
 380                                         ast_log(LOG_WARNING, "Loading module %s failed!\n", v->value);
 381                                         if (cfg)
 382                                                 ast_destroy(cfg);
 383                                         return -1;
 384                                 }
 385                         }
 386                         v=v->next;
 387                 }
 388         }
 389         if (!cfg || ast_true(ast_variable_retrieve(cfg, "modules", "autoload"))) {
 390                 /* Load all modules */
 391                 DIR *mods;
 392                 struct dirent *d;
 393                 int x;
 394                 /* Make two passes.  First, load any resource modules, then load the others. */
 395                 for (x=0;x<2;x++) {
 396                         mods = opendir((char *)ast_config_AST_MODULE_DIR);
 397                         if (mods) {
 398                                 while((d = readdir(mods))) {
 399                                         /* Must end in .so to load it.  */
 400                                         if ((strlen(d->d_name) > 3) && (x || !strncasecmp(d->d_name, "res_", 4)) &&
 401                                             !strcasecmp(d->d_name + strlen(d->d_name) - 3, ".so") &&
 402                                                 !ast_resource_exists(d->d_name)) {
 403                                                 /* It's a shared library -- Just be sure we're allowed to load it -- kinda
 404                                                    an inefficient way to do it, but oh well. */
 405                                                 if (cfg) {
 406                                                         v = ast_variable_browse(cfg, "modules");
 407                                                         while(v) {
 408                                                                 if (!strcasecmp(v->name, "noload") &&
 409                                                                     !strcasecmp(v->value, d->d_name))
 410                                                                         break;
 411                                                                 v = v->next;
 412                                                         }
 413                                                         if (v) {
 414                                                                 if (option_verbose) {
 415                                                                         ast_verbose( VERBOSE_PREFIX_1 "[skipping %s]\n", d->d_name);
 416                                                                         fflush(stdout);
 417                                                                 }
 418                                                                 continue;
 419                                                         }
 420
 421                                                 }
 422                                             if (option_debug && !option_verbose)
 423                                                         ast_log(LOG_DEBUG, "Loading module %s\n", d->d_name);
 424                                                 if (option_verbose) {
 425                                                         ast_verbose( VERBOSE_PREFIX_1 "[%s]", term_color(tmp, d->d_name, COLOR_BRWHITE, 0, sizeof(tmp)));
 426                                                         fflush(stdout);
 427                                                 }
 428                                                 if (ast_load_resource(d->d_name)) {
 429                                                         ast_log(LOG_WARNING, "Loading module %s failed!\n", d->d_name);
 430                                                         if (cfg)
 431                                                                 ast_destroy(cfg);
 432                                                         return -1;
 433                                                 }
 434                                         }
 435                                 }
 436                                 closedir(mods);
 437                         } else {
 438                                 if (!option_quiet)
 439                                         ast_log(LOG_WARNING, "Unable to open modules directory %s.\n", (char *)ast_config_AST_MODULE_DIR);
 440                         }
 441                 }
 442         }
 443         ast_destroy(cfg);
 444         return 0;
 445 }
 446
 447 void ast_update_use_count(void)
 448 {
 449         /* Notify any module monitors that the use count for a
 450            resource has changed */
 451         struct loadupdate *m;
 452         if (ast_mutex_lock(&modlock))
 453                 ast_log(LOG_WARNING, "Failed to lock\n");
 454         m = updaters;
 455         while(m) {
 456                 m->updater();
 457                 m = m->next;
 458         }
 459         ast_mutex_unlock(&modlock);
 460
 461 }
 462
 463 int ast_update_module_list(int (*modentry)(char *module, char *description, int usecnt))
 464 {
 465         struct module *m;
 466         int unlock = -1;
 467         if (ast_mutex_trylock(&modlock))
 468                 unlock = 0;
 469         m = module_list;
 470         while(m) {
 471                 modentry(m->resource, m->description(), m->usecount());
 472                 m = m->next;
 473         }
 474         if (unlock)
 475                 ast_mutex_unlock(&modlock);
 476         return 0;
 477 }
 478
 479 int ast_loader_register(int (*v)(void))
 480 {
 481         struct loadupdate *tmp;
 482         /* XXX Should be more flexible here, taking > 1 verboser XXX */
 483         if ((tmp = malloc(sizeof (struct loadupdate)))) {
 484                 tmp->updater = v;
 485                 if (ast_mutex_lock(&modlock))
 486                         ast_log(LOG_WARNING, "Failed to lock\n");
 487                 tmp->next = updaters;
 488                 updaters = tmp;
 489                 ast_mutex_unlock(&modlock);
 490                 return 0;
 491         }
 492         return -1;
 493 }
 494
 495 int ast_loader_unregister(int (*v)(void))
 496 {
 497         int res = -1;
 498         struct loadupdate *tmp, *tmpl=NULL;
 499         if (ast_mutex_lock(&modlock))
 500                 ast_log(LOG_WARNING, "Failed to lock\n");
 501         tmp = updaters;
 502         while(tmp) {
 503                 if (tmp->updater == v)  {
 504                         if (tmpl)
 505                                 tmpl->next = tmp->next;
 506                         else
 507                                 updaters = tmp->next;
 508                         break;
 509                 }
 510                 tmpl = tmp;
 511                 tmp = tmp->next;
 512         }
 513         if (tmp)
 514                 res = 0;
 515         ast_mutex_unlock(&modlock);
 516         return res;
 517 }