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