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