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