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         read_ast_cust_config();
 161         reload_manager();
 162         ast_enum_reload();
 163         ast_rtp_reload();
 164         time(&ast_lastreloadtime);
 165
 166         ast_mutex_lock(&modlock);
 167         m = module_list;
 168         while(m) {
 169                 if (!name || !strcasecmp(name, m->resource)) {
 170                         if (m->reload) {
 171                                 if (option_verbose > 2)
 172                                         ast_verbose(VERBOSE_PREFIX_3 "Reloading module '%s' (%s)\n", m->resource, m->description());
 173                                 m->reload();
 174                         }
 175                 }
 176                 m = m->next;
 177         }
 178         ast_mutex_unlock(&modlock);
 179         ast_mutex_unlock(&reloadlock);
 180 }
 181
 182 int ast_load_resource(char *resource_name)
 183 {
 184         static char fn[256];
 185         int errors=0;
 186         int res;
 187         struct module *m;
 188         int flags=RTLD_NOW;
 189 #ifdef RTLD_GLOBAL
 190         char *val;
 191 #endif
 192         char *key;
 193         int o;
 194         struct ast_config *cfg;
 195         char tmp[80];
 196         /* Keep the module file parsing silent */
 197         o = option_verbose;
 198         if (strncasecmp(resource_name, "res_", 4)) {
 199                 option_verbose = 0;
 200                 cfg = ast_load(AST_MODULE_CONFIG);
 201                 option_verbose = o;
 202                 if (cfg) {
 203 #ifdef RTLD_GLOBAL
 204                         if ((val = ast_variable_retrieve(cfg, "global", resource_name))
 205                                         && ast_true(val))
 206                                 flags |= RTLD_GLOBAL;
 207 #endif
 208                         ast_destroy(cfg);
 209                 }
 210         } else {
 211                 /* Resource modules are always loaded global and lazy */
 212 #ifdef RTLD_GLOBAL
 213                 flags = (RTLD_GLOBAL | RTLD_LAZY);
 214 #else
 215                 flags = RTLD_LAZY;
 216 #endif
 217         }
 218
 219         if (ast_mutex_lock(&modlock))
 220                 ast_log(LOG_WARNING, "Failed to lock\n");
 221         m = module_list;
 222         while(m) {
 223                 if (!strcasecmp(m->resource, resource_name)) {
 224                         ast_log(LOG_WARNING, "Module '%s' already exists\n", resource_name);
 225                         ast_mutex_unlock(&modlock);
 226                         return -1;
 227                 }
 228                 m = m->next;
 229         }
 230         m = malloc(sizeof(struct module));
 231         if (!m) {
 232                 ast_log(LOG_WARNING, "Out of memory\n");
 233                 ast_mutex_unlock(&modlock);
 234                 return -1;
 235         }
 236         strncpy(m->resource, resource_name, sizeof(m->resource)-1);
 237         if (resource_name[0] == '/') {
 238                 strncpy(fn, resource_name, sizeof(fn)-1);
 239         } else {
 240                 snprintf(fn, sizeof(fn), "%s/%s", (char *)ast_config_AST_MODULE_DIR, resource_name);
 241         }
 242         m->lib = dlopen(fn, flags);
 243         if (!m->lib) {
 244                 ast_log(LOG_WARNING, "%s\n", dlerror());
 245                 free(m);
 246                 ast_mutex_unlock(&modlock);
 247                 return -1;
 248         }
 249         m->load_module = dlsym(m->lib, "load_module");
 250         if (m->load_module == NULL)
 251                 m->load_module = dlsym(m->lib, "_load_module");
 252         if (!m->load_module) {
 253                 ast_log(LOG_WARNING, "No load_module in module %s\n", fn);
 254                 errors++;
 255         }
 256         m->unload_module = dlsym(m->lib, "unload_module");
 257         if (m->unload_module == NULL)
 258                 m->unload_module = dlsym(m->lib, "_unload_module");
 259         if (!m->unload_module) {
 260                 ast_log(LOG_WARNING, "No unload_module in module %s\n", fn);
 261                 errors++;
 262         }
 263         m->usecount = dlsym(m->lib, "usecount");
 264         if (m->usecount == NULL)
 265                 m->usecount = dlsym(m->lib, "_usecount");
 266         if (!m->usecount) {
 267                 ast_log(LOG_WARNING, "No usecount in module %s\n", fn);
 268                 errors++;
 269         }
 270         m->description = dlsym(m->lib, "description");
 271         if (m->description == NULL)
 272                 m->description = dlsym(m->lib, "_description");
 273         if (!m->description) {
 274                 ast_log(LOG_WARNING, "No description in module %s\n", fn);
 275                 errors++;
 276         }
 277         m->key = dlsym(m->lib, "key");
 278         if (m->key == NULL)
 279                 m->key = dlsym(m->lib, "_key");
 280         if (!m->key) {
 281                 ast_log(LOG_WARNING, "No key routine in module %s\n", fn);
 282                 errors++;
 283         }
 284         m->reload = dlsym(m->lib, "reload");
 285         if (m->reload == NULL)
 286                 m->reload = dlsym(m->lib, "_reload");
 287         if (!m->key || !(key = m->key())) {
 288                 ast_log(LOG_WARNING, "Key routine returned NULL in module %s\n", fn);
 289                 key = NULL;
 290                 errors++;
 291         }
 292         if (key && verify_key(key)) {
 293                 ast_log(LOG_WARNING, "Unexpected key returned by module %s\n", fn);
 294                 errors++;
 295         }
 296         if (errors) {
 297                 ast_log(LOG_WARNING, "%d error(s) loading module %s, aborted\n", errors, fn);
 298                 dlclose(m->lib);
 299                 free(m);
 300                 ast_mutex_unlock(&modlock);
 301                 return -1;
 302         }
 303         if (!fully_booted) {
 304                 if (option_verbose)
 305                         ast_verbose( " => (%s)\n", term_color(tmp, m->description(), COLOR_BROWN, COLOR_BLACK, sizeof(tmp)));
 306                 if (option_console && !option_verbose)
 307                         ast_verbose( ".");
 308         } else {
 309                 if (option_verbose)
 310                         ast_verbose(VERBOSE_PREFIX_1 "Loaded %s => (%s)\n", fn, m->description());
 311         }
 312
 313         // add module 'm' to end of module_list chain
 314         // so reload commands will be issued in same order modules were loaded
 315         m->next = NULL;
 316         if (module_list == NULL) {
 317                 // empty list so far, add at front
 318                 module_list = m;
 319         }
 320         else {
 321                 struct module *i;
 322                 // find end of chain, and add there
 323                 for (i = module_list; i->next; i = i->next)
 324                         ;
 325                 i->next = m;
 326         }
 327
 328         ast_mutex_unlock(&modlock);
 329         if ((res = m->load_module())) {
 330                 ast_log(LOG_WARNING, "%s: load_module failed, returning %d\n", m->resource, res);
 331                 ast_unload_resource(resource_name, 0);
 332                 return -1;
 333         }
 334         ast_update_use_count();
 335         return 0;
 336 }
 337
 338 static int ast_resource_exists(char *resource)
 339 {
 340         struct module *m;
 341         if (ast_mutex_lock(&modlock))
 342                 ast_log(LOG_WARNING, "Failed to lock\n");
 343         m = module_list;
 344         while(m) {
 345                 if (!strcasecmp(resource, m->resource))
 346                         break;
 347                 m = m->next;
 348         }
 349         ast_mutex_unlock(&modlock);
 350         if (m)
 351                 return -1;
 352         else
 353                 return 0;
 354 }
 355
 356 int load_modules()
 357 {
 358         struct ast_config *cfg;
 359         struct ast_variable *v;
 360         char tmp[80];
 361         if (option_verbose)
 362                 ast_verbose( "Asterisk Dynamic Loader Starting:\n");
 363         cfg = ast_load(AST_MODULE_CONFIG);
 364         if (cfg) {
 365                 /* Load explicitly defined modules */
 366                 v = ast_variable_browse(cfg, "modules");
 367                 while(v) {
 368                         if (!strcasecmp(v->name, "load")) {
 369                                 if (option_debug && !option_verbose)
 370                                         ast_log(LOG_DEBUG, "Loading module %s\n", v->value);
 371                                 if (option_verbose) {
 372                                         ast_verbose( VERBOSE_PREFIX_1 "[%s]", term_color(tmp, v->value, COLOR_BRWHITE, 0, sizeof(tmp)));
 373                                         fflush(stdout);
 374                                 }
 375                                 if (ast_load_resource(v->value)) {
 376                                         ast_log(LOG_WARNING, "Loading module %s failed!\n", v->value);
 377                                         if (cfg)
 378                                                 ast_destroy(cfg);
 379                                         return -1;
 380                                 }
 381                         }
 382                         v=v->next;
 383                 }
 384         }
 385         if (!cfg || ast_true(ast_variable_retrieve(cfg, "modules", "autoload"))) {
 386                 /* Load all modules */
 387                 DIR *mods;
 388                 struct dirent *d;
 389                 int x;
 390                 /* Make two passes.  First, load any resource modules, then load the others. */
 391                 for (x=0;x<2;x++) {
 392                         mods = opendir((char *)ast_config_AST_MODULE_DIR);
 393                         if (mods) {
 394                                 while((d = readdir(mods))) {
 395                                         /* Must end in .so to load it.  */
 396                                         if ((strlen(d->d_name) > 3) && (x || !strncasecmp(d->d_name, "res_", 4)) &&
 397                                             !strcasecmp(d->d_name + strlen(d->d_name) - 3, ".so") &&
 398                                                 !ast_resource_exists(d->d_name)) {
 399                                                 /* It's a shared library -- Just be sure we're allowed to load it -- kinda
 400                                                    an inefficient way to do it, but oh well. */
 401                                                 if (cfg) {
 402                                                         v = ast_variable_browse(cfg, "modules");
 403                                                         while(v) {
 404                                                                 if (!strcasecmp(v->name, "noload") &&
 405                                                                     !strcasecmp(v->value, d->d_name))
 406                                                                         break;
 407                                                                 v = v->next;
 408                                                         }
 409                                                         if (v) {
 410                                                                 if (option_verbose) {
 411                                                                         ast_verbose( VERBOSE_PREFIX_1 "[skipping %s]\n", d->d_name);
 412                                                                         fflush(stdout);
 413                                                                 }
 414                                                                 continue;
 415                                                         }
 416
 417                                                 }
 418                                             if (option_debug && !option_verbose)
 419                                                         ast_log(LOG_DEBUG, "Loading module %s\n", d->d_name);
 420                                                 if (option_verbose) {
 421                                                         ast_verbose( VERBOSE_PREFIX_1 "[%s]", term_color(tmp, d->d_name, COLOR_BRWHITE, 0, sizeof(tmp)));
 422                                                         fflush(stdout);
 423                                                 }
 424                                                 if (ast_load_resource(d->d_name)) {
 425                                                         ast_log(LOG_WARNING, "Loading module %s failed!\n", d->d_name);
 426                                                         if (cfg)
 427                                                                 ast_destroy(cfg);
 428                                                         return -1;
 429                                                 }
 430                                         }
 431                                 }
 432                                 closedir(mods);
 433                         } else {
 434                                 if (!option_quiet)
 435                                         ast_log(LOG_WARNING, "Unable to open modules directory %s.\n", (char *)ast_config_AST_MODULE_DIR);
 436                         }
 437                 }
 438         }
 439         ast_destroy(cfg);
 440         return 0;
 441 }
 442
 443 void ast_update_use_count(void)
 444 {
 445         /* Notify any module monitors that the use count for a
 446            resource has changed */
 447         struct loadupdate *m;
 448         if (ast_mutex_lock(&modlock))
 449                 ast_log(LOG_WARNING, "Failed to lock\n");
 450         m = updaters;
 451         while(m) {
 452                 m->updater();
 453                 m = m->next;
 454         }
 455         ast_mutex_unlock(&modlock);
 456
 457 }
 458
 459 int ast_update_module_list(int (*modentry)(char *module, char *description, int usecnt))
 460 {
 461         struct module *m;
 462         int unlock = -1;
 463         if (ast_mutex_trylock(&modlock))
 464                 unlock = 0;
 465         m = module_list;
 466         while(m) {
 467                 modentry(m->resource, m->description(), m->usecount());
 468                 m = m->next;
 469         }
 470         if (unlock)
 471                 ast_mutex_unlock(&modlock);
 472         return 0;
 473 }
 474
 475 int ast_loader_register(int (*v)(void))
 476 {
 477         struct loadupdate *tmp;
 478         /* XXX Should be more flexible here, taking > 1 verboser XXX */
 479         if ((tmp = malloc(sizeof (struct loadupdate)))) {
 480                 tmp->updater = v;
 481                 if (ast_mutex_lock(&modlock))
 482                         ast_log(LOG_WARNING, "Failed to lock\n");
 483                 tmp->next = updaters;
 484                 updaters = tmp;
 485                 ast_mutex_unlock(&modlock);
 486                 return 0;
 487         }
 488         return -1;
 489 }
 490
 491 int ast_loader_unregister(int (*v)(void))
 492 {
 493         int res = -1;
 494         struct loadupdate *tmp, *tmpl=NULL;
 495         if (ast_mutex_lock(&modlock))
 496                 ast_log(LOG_WARNING, "Failed to lock\n");
 497         tmp = updaters;
 498         while(tmp) {
 499                 if (tmp->updater == v)  {
 500                         if (tmpl)
 501                                 tmpl->next = tmp->next;
 502                         else
 503                                 updaters = tmp->next;
 504                         break;
 505                 }
 506                 tmpl = tmp;
 507                 tmp = tmp->next;
 508         }
 509         if (tmp)
 510                 res = 0;
 511         ast_mutex_unlock(&modlock);
 512         return res;
 513 }