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                 }
 140                 ml = m;
 141                 m = m->next;
 142         }
 143         ast_mutex_unlock(&modlock);
 144         ast_update_use_count();
 145         return res;
 146 }
 147
 148 void ast_module_reload(void)
 149 {
 150         struct module *m;
 151
 152         /* We'll do the logger and manager the favor of calling its reload here first */
 153
 154         if (ast_mutex_trylock(&reloadlock)) {
 155                 ast_verbose("The previous reload command didn't finish yet\n");
 156                 return;
 157         }
 158         reload_manager();
 159         ast_enum_reload();
 160         ast_rtp_reload();
 161         time(&ast_lastreloadtime);
 162
 163         ast_mutex_lock(&modlock);
 164         m = module_list;
 165         while(m) {
 166                 if (m->reload) {
 167                         if (option_verbose > 2)
 168                                 ast_verbose(VERBOSE_PREFIX_3 "Reloading module '%s' (%s)\n", m->resource, m->description());
 169                         m->reload();
 170                 }
 171                 m = m->next;
 172         }
 173         ast_mutex_unlock(&modlock);
 174         ast_mutex_unlock(&reloadlock);
 175 }
 176
 177 int ast_load_resource(char *resource_name)
 178 {
 179         static char fn[256];
 180         int errors=0;
 181         int res;
 182         struct module *m;
 183         int flags=RTLD_NOW;
 184 #ifdef RTLD_GLOBAL
 185         char *val;
 186 #endif
 187         char *key;
 188         int o;
 189         struct ast_config *cfg;
 190         char tmp[80];
 191         /* Keep the module file parsing silent */
 192         o = option_verbose;
 193         if (strncasecmp(resource_name, "res_", 4)) {
 194                 option_verbose = 0;
 195                 cfg = ast_load(AST_MODULE_CONFIG);
 196                 option_verbose = o;
 197                 if (cfg) {
 198 #ifdef RTLD_GLOBAL
 199                         if ((val = ast_variable_retrieve(cfg, "global", resource_name))
 200                                         && ast_true(val))
 201                                 flags |= RTLD_GLOBAL;
 202 #endif
 203                         ast_destroy(cfg);
 204                 }
 205         } else {
 206                 /* Resource modules are always loaded global and lazy */
 207 #ifdef RTLD_GLOBAL
 208                 flags = (RTLD_GLOBAL | RTLD_LAZY);
 209 #else
 210                 flags = RTLD_LAZY;
 211 #endif
 212         }
 213
 214         if (ast_mutex_lock(&modlock))
 215                 ast_log(LOG_WARNING, "Failed to lock\n");
 216         m = module_list;
 217         while(m) {
 218                 if (!strcasecmp(m->resource, resource_name)) {
 219                         ast_log(LOG_WARNING, "Module '%s' already exists\n", resource_name);
 220                         ast_mutex_unlock(&modlock);
 221                         return -1;
 222                 }
 223                 m = m->next;
 224         }
 225         m = malloc(sizeof(struct module));
 226         if (!m) {
 227                 ast_log(LOG_WARNING, "Out of memory\n");
 228                 ast_mutex_unlock(&modlock);
 229                 return -1;
 230         }
 231         strncpy(m->resource, resource_name, sizeof(m->resource)-1);
 232         if (resource_name[0] == '/') {
 233                 strncpy(fn, resource_name, sizeof(fn)-1);
 234         } else {
 235                 snprintf(fn, sizeof(fn), "%s/%s", (char *)ast_config_AST_MODULE_DIR, resource_name);
 236         }
 237         m->lib = dlopen(fn, flags);
 238         if (!m->lib) {
 239                 ast_log(LOG_WARNING, "%s\n", dlerror());
 240                 free(m);
 241                 ast_mutex_unlock(&modlock);
 242                 return -1;
 243         }
 244         m->load_module = dlsym(m->lib, "load_module");
 245         if (m->load_module == NULL)
 246                 m->load_module = dlsym(m->lib, "_load_module");
 247         if (!m->load_module) {
 248                 ast_log(LOG_WARNING, "No load_module in module %s\n", fn);
 249                 errors++;
 250         }
 251         m->unload_module = dlsym(m->lib, "unload_module");
 252         if (m->unload_module == NULL)
 253                 m->unload_module = dlsym(m->lib, "_unload_module");
 254         if (!m->unload_module) {
 255                 ast_log(LOG_WARNING, "No unload_module in module %s\n", fn);
 256                 errors++;
 257         }
 258         m->usecount = dlsym(m->lib, "usecount");
 259         if (m->usecount == NULL)
 260                 m->usecount = dlsym(m->lib, "_usecount");
 261         if (!m->usecount) {
 262                 ast_log(LOG_WARNING, "No usecount in module %s\n", fn);
 263                 errors++;
 264         }
 265         m->description = dlsym(m->lib, "description");
 266         if (m->description == NULL)
 267                 m->description = dlsym(m->lib, "_description");
 268         if (!m->description) {
 269                 ast_log(LOG_WARNING, "No description in module %s\n", fn);
 270                 errors++;
 271         }
 272         m->key = dlsym(m->lib, "key");
 273         if (m->key == NULL)
 274                 m->key = dlsym(m->lib, "_key");
 275         if (!m->key) {
 276                 ast_log(LOG_WARNING, "No key routine in module %s\n", fn);
 277                 errors++;
 278         }
 279         m->reload = dlsym(m->lib, "reload");
 280         if (m->reload == NULL)
 281                 m->reload = dlsym(m->lib, "_reload");
 282         if (m->key && !(key = m->key())) {
 283                 ast_log(LOG_WARNING, "Key routine returned NULL in module %s\n", fn);
 284                 errors++;
 285         } else
 286                 key = NULL;
 287         if (key && verify_key(key)) {
 288                 ast_log(LOG_WARNING, "Unexpected key returned by module %s\n", fn);
 289                 errors++;
 290         }
 291         if (errors) {
 292                 ast_log(LOG_WARNING, "%d error(s) loading module %s, aborted\n", errors, fn);
 293                 dlclose(m->lib);
 294                 free(m);
 295                 ast_mutex_unlock(&modlock);
 296                 return -1;
 297         }
 298         if (!fully_booted) {
 299                 if (option_verbose)
 300                         ast_verbose( " => (%s)\n", term_color(tmp, m->description(), COLOR_BROWN, COLOR_BLACK, sizeof(tmp)));
 301                 if (option_console && !option_verbose)
 302                         ast_verbose( ".");
 303         } else {
 304                 if (option_verbose)
 305                         ast_verbose(VERBOSE_PREFIX_1 "Loaded %s => (%s)\n", fn, m->description());
 306         }
 307         m->next = module_list;
 308
 309         module_list = m;
 310         ast_mutex_unlock(&modlock);
 311         if ((res = m->load_module())) {
 312                 ast_log(LOG_WARNING, "%s: load_module failed, returning %d\n", m->resource, res);
 313                 ast_unload_resource(resource_name, 0);
 314                 return -1;
 315         }
 316         ast_update_use_count();
 317         return 0;
 318 }
 319
 320 static int ast_resource_exists(char *resource)
 321 {
 322         struct module *m;
 323         if (ast_mutex_lock(&modlock))
 324                 ast_log(LOG_WARNING, "Failed to lock\n");
 325         m = module_list;
 326         while(m) {
 327                 if (!strcasecmp(resource, m->resource))
 328                         break;
 329                 m = m->next;
 330         }
 331         ast_mutex_unlock(&modlock);
 332         if (m)
 333                 return -1;
 334         else
 335                 return 0;
 336 }
 337
 338 int load_modules()
 339 {
 340         struct ast_config *cfg;
 341         struct ast_variable *v;
 342         char tmp[80];
 343         if (option_verbose)
 344                 ast_verbose( "Asterisk Dynamic Loader Starting:\n");
 345         cfg = ast_load(AST_MODULE_CONFIG);
 346         if (cfg) {
 347                 /* Load explicitly defined modules */
 348                 v = ast_variable_browse(cfg, "modules");
 349                 while(v) {
 350                         if (!strcasecmp(v->name, "load")) {
 351                                 if (option_debug && !option_verbose)
 352                                         ast_log(LOG_DEBUG, "Loading module %s\n", v->value);
 353                                 if (option_verbose) {
 354                                         ast_verbose( VERBOSE_PREFIX_1 "[%s]", term_color(tmp, v->value, COLOR_BRWHITE, 0, sizeof(tmp)));
 355                                         fflush(stdout);
 356                                 }
 357                                 if (ast_load_resource(v->value)) {
 358                                         ast_log(LOG_WARNING, "Loading module %s failed!\n", v->value);
 359                                         if (cfg)
 360                                                 ast_destroy(cfg);
 361                                         return -1;
 362                                 }
 363                         }
 364                         v=v->next;
 365                 }
 366         }
 367         if (!cfg || ast_true(ast_variable_retrieve(cfg, "modules", "autoload"))) {
 368                 /* Load all modules */
 369                 DIR *mods;
 370                 struct dirent *d;
 371                 int x;
 372                 /* Make two passes.  First, load any resource modules, then load the others. */
 373                 for (x=0;x<2;x++) {
 374                         mods = opendir((char *)ast_config_AST_MODULE_DIR);
 375                         if (mods) {
 376                                 while((d = readdir(mods))) {
 377                                         /* Must end in .so to load it.  */
 378                                         if ((strlen(d->d_name) > 3) && (x || !strncasecmp(d->d_name, "res_", 4)) &&
 379                                             !strcasecmp(d->d_name + strlen(d->d_name) - 3, ".so") &&
 380                                                 !ast_resource_exists(d->d_name)) {
 381                                                 /* It's a shared library -- Just be sure we're allowed to load it -- kinda
 382                                                    an inefficient way to do it, but oh well. */
 383                                                 if (cfg) {
 384                                                         v = ast_variable_browse(cfg, "modules");
 385                                                         while(v) {
 386                                                                 if (!strcasecmp(v->name, "noload") &&
 387                                                                     !strcasecmp(v->value, d->d_name))
 388                                                                         break;
 389                                                                 v = v->next;
 390                                                         }
 391                                                         if (v) {
 392                                                                 if (option_verbose) {
 393                                                                         ast_verbose( VERBOSE_PREFIX_1 "[skipping %s]\n", d->d_name);
 394                                                                         fflush(stdout);
 395                                                                 }
 396                                                                 continue;
 397                                                         }
 398
 399                                                 }
 400                                             if (option_debug && !option_verbose)
 401                                                         ast_log(LOG_DEBUG, "Loading module %s\n", d->d_name);
 402                                                 if (option_verbose) {
 403                                                         ast_verbose( VERBOSE_PREFIX_1 "[%s]", term_color(tmp, d->d_name, COLOR_BRWHITE, 0, sizeof(tmp)));
 404                                                         fflush(stdout);
 405                                                 }
 406                                                 if (ast_load_resource(d->d_name)) {
 407                                                         ast_log(LOG_WARNING, "Loading module %s failed!\n", d->d_name);
 408                                                         if (cfg)
 409                                                                 ast_destroy(cfg);
 410                                                         return -1;
 411                                                 }
 412                                         }
 413                                 }
 414                                 closedir(mods);
 415                         } else {
 416                                 if (!option_quiet)
 417                                         ast_log(LOG_WARNING, "Unable to open modules directory %s.\n", (char *)ast_config_AST_MODULE_DIR);
 418                         }
 419                 }
 420         }
 421         ast_destroy(cfg);
 422         return 0;
 423 }
 424
 425 void ast_update_use_count(void)
 426 {
 427         /* Notify any module monitors that the use count for a
 428            resource has changed */
 429         struct loadupdate *m;
 430         if (ast_mutex_lock(&modlock))
 431                 ast_log(LOG_WARNING, "Failed to lock\n");
 432         m = updaters;
 433         while(m) {
 434                 m->updater();
 435                 m = m->next;
 436         }
 437         ast_mutex_unlock(&modlock);
 438
 439 }
 440
 441 int ast_update_module_list(int (*modentry)(char *module, char *description, int usecnt))
 442 {
 443         struct module *m;
 444         int unlock = -1;
 445         if (ast_mutex_trylock(&modlock))
 446                 unlock = 0;
 447         m = module_list;
 448         while(m) {
 449                 modentry(m->resource, m->description(), m->usecount());
 450                 m = m->next;
 451         }
 452         if (unlock)
 453                 ast_mutex_unlock(&modlock);
 454         return 0;
 455 }
 456
 457 int ast_loader_register(int (*v)(void))
 458 {
 459         struct loadupdate *tmp;
 460         /* XXX Should be more flexible here, taking > 1 verboser XXX */
 461         if ((tmp = malloc(sizeof (struct loadupdate)))) {
 462                 tmp->updater = v;
 463                 if (ast_mutex_lock(&modlock))
 464                         ast_log(LOG_WARNING, "Failed to lock\n");
 465                 tmp->next = updaters;
 466                 updaters = tmp;
 467                 ast_mutex_unlock(&modlock);
 468                 return 0;
 469         }
 470         return -1;
 471 }
 472
 473 int ast_loader_unregister(int (*v)(void))
 474 {
 475         int res = -1;
 476         struct loadupdate *tmp, *tmpl=NULL;
 477         if (ast_mutex_lock(&modlock))
 478                 ast_log(LOG_WARNING, "Failed to lock\n");
 479         tmp = updaters;
 480         while(tmp) {
 481                 if (tmp->updater == v)  {
 482                         if (tmpl)
 483                                 tmpl->next = tmp->next;
 484                         else
 485                                 updaters = tmp->next;
 486                         break;
 487                 }
 488                 tmpl = tmp;
 489                 tmp = tmp->next;
 490         }
 491         if (tmp)
 492                 res = 0;
 493         ast_mutex_unlock(&modlock);
 494         return res;
 495 }