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 <dlfcn.h>
  24 #define __USE_GNU
  25 #include <pthread.h>
  26 #include "asterisk.h"
  27
  28 struct module {
  29         int (*load_module)(void);
  30         int (*unload_module)(void);
  31         int (*usecount)(void);
  32         char *(*description)(void);
  33         void *lib;
  34         char resource[256];
  35         struct module *next;
  36 };
  37
  38 static struct loadupdate {
  39         int (*updater)(void);
  40         struct loadupdate *next;
  41 } *updaters = NULL;
  42
  43 static pthread_mutex_t modlock = PTHREAD_MUTEX_INITIALIZER;
  44
  45 static struct module *module_list=NULL;
  46
  47 int ast_unload_resource(char *resource_name, int force)
  48 {
  49         struct module *m, *ml = NULL;
  50         int res = -1;
  51         if (pthread_mutex_lock(&modlock))
  52                 ast_log(LOG_WARNING, "Failed to lock\n");
  53         m = module_list;
  54         while(m) {
  55                 if (!strcasecmp(m->resource, resource_name)) {
  56                         if ((res = m->usecount()) > 0)  {
  57                                 if (force)
  58                                         ast_log(LOG_WARNING, "Warning:  Forcing removal of module %s with use count %d\n", resource_name, res);
  59                                 else {
  60                                         ast_log(LOG_WARNING, "Soft unload failed, '%s' has use count %d\n", resource_name, res);
  61                                         pthread_mutex_unlock(&modlock);
  62                                         return -1;
  63                                 }
  64                         }
  65                         res = m->unload_module();
  66                         if (res) {
  67                                 ast_log(LOG_WARNING, "Firm unload failed for %s\n", resource_name);
  68                                 if (force <= AST_FORCE_FIRM) {
  69                                         pthread_mutex_unlock(&modlock);
  70                                         return -1;
  71                                 } else
  72                                         ast_log(LOG_WARNING, "** Dangerous **: Unloading resource anyway, at user request\n");
  73                         }
  74                         if (ml)
  75                                 ml->next = m->next;
  76                         else
  77                                 module_list = m->next;
  78                         dlclose(m->lib);
  79                         free(m);
  80                 }
  81                 ml = m;
  82                 m = m->next;
  83         }
  84         pthread_mutex_unlock(&modlock);
  85         ast_update_use_count();
  86         return res;
  87 }
  88
  89 int ast_load_resource(char *resource_name)
  90 {
  91         static char fn[256];
  92         int errors=0;
  93         int res;
  94         struct module *m;
  95         int flags=0;
  96         char *val;
  97         int o;
  98         struct ast_config *cfg;
  99         /* Keep the module file parsing silent */
 100         o = option_verbose;
 101         option_verbose = 0;
 102         cfg = ast_load(AST_MODULE_CONFIG);
 103         option_verbose = o;
 104         if (cfg) {
 105                 if ((val = ast_variable_retrieve(cfg, "global", resource_name))
 106                                 && ast_true(val))
 107                         flags |= RTLD_GLOBAL;
 108                 ast_destroy(cfg);
 109         }
 110
 111         if (pthread_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                         ast_log(LOG_WARNING, "Module '%s' already exists\n", resource_name);
 117                         pthread_mutex_unlock(&modlock);
 118                         return -1;
 119                 }
 120                 m = m->next;
 121         }
 122         m = malloc(sizeof(struct module));
 123         if (!m) {
 124                 ast_log(LOG_WARNING, "Out of memory\n");
 125                 pthread_mutex_unlock(&modlock);
 126                 return -1;
 127         }
 128         strncpy(m->resource, resource_name, sizeof(m->resource));
 129         if (resource_name[0] == '/') {
 130                 strncpy(fn, resource_name, sizeof(fn));
 131         } else {
 132                 snprintf(fn, sizeof(fn), "%s/%s", AST_MODULE_DIR, resource_name);
 133         }
 134         m->lib = dlopen(fn, RTLD_NOW | flags);
 135         if (!m->lib) {
 136                 ast_log(LOG_WARNING, "%s\n", dlerror());
 137                 free(m);
 138                 pthread_mutex_unlock(&modlock);
 139                 return -1;
 140         }
 141         m->load_module = dlsym(m->lib, "load_module");
 142         if (!m->load_module) {
 143                 ast_log(LOG_WARNING, "No load_module in module %s\n", fn);
 144                 errors++;
 145         }
 146         m->unload_module = dlsym(m->lib, "unload_module");
 147         if (!m->unload_module) {
 148                 ast_log(LOG_WARNING, "No unload_module in module %s\n", fn);
 149                 errors++;
 150         }
 151         m->usecount = dlsym(m->lib, "usecount");
 152         if (!m->usecount) {
 153                 ast_log(LOG_WARNING, "No usecount in module %s\n", fn);
 154                 errors++;
 155         }
 156         m->description = dlsym(m->lib, "description");
 157         if (!m->description) {
 158                 ast_log(LOG_WARNING, "No description in module %s\n", fn);
 159                 errors++;
 160         }
 161         if (errors) {
 162                 ast_log(LOG_WARNING, "%d error(s) loading module %s, aborted\n", errors, fn);
 163                 dlclose(m->lib);
 164                 free(m);
 165                 pthread_mutex_unlock(&modlock);
 166                 return -1;
 167         }
 168         if (!fully_booted) {
 169                 if (option_verbose)
 170                         ast_verbose( " => (%s)\n", m->description());
 171                 if (option_console && !option_verbose)
 172                         ast_verbose( ".");
 173         } else {
 174                 if (option_verbose)
 175                         ast_verbose(VERBOSE_PREFIX_1 "Loaded %s => (%s)\n", fn, m->description());
 176         }
 177         m->next = module_list;
 178         module_list = m;
 179         pthread_mutex_unlock(&modlock);
 180         if ((res = m->load_module())) {
 181                 ast_log(LOG_WARNING, "%s: load_module failed, returning %d\n", m->resource, res);
 182                 ast_unload_resource(resource_name, 0);
 183                 return -1;
 184         }
 185         ast_update_use_count();
 186         return 0;
 187 }
 188
 189 static int ast_resource_exists(char *resource)
 190 {
 191         struct module *m;
 192         if (pthread_mutex_lock(&modlock))
 193                 ast_log(LOG_WARNING, "Failed to lock\n");
 194         m = module_list;
 195         while(m) {
 196                 if (!strcasecmp(resource, m->resource))
 197                         break;
 198                 m = m->next;
 199         }
 200         pthread_mutex_unlock(&modlock);
 201         if (m)
 202                 return -1;
 203         else
 204                 return 0;
 205 }
 206
 207 int load_modules()
 208 {
 209         struct ast_config *cfg;
 210         struct ast_variable *v;
 211         if (option_verbose)
 212                 ast_verbose( "Asterisk Dynamic Loader Starting:\n");
 213         cfg = ast_load(AST_MODULE_CONFIG);
 214         if (cfg) {
 215                 /* Load explicitly defined modules */
 216                 v = ast_variable_browse(cfg, "modules");
 217                 while(v) {
 218                         if (!strcasecmp(v->name, "load")) {
 219                                 if (option_debug && !option_verbose)
 220                                         ast_log(LOG_DEBUG, "Loading module %s\n", v->value);
 221                                 if (option_verbose) {
 222                                         ast_verbose( " [%s]", v->value);
 223                                         fflush(stdout);
 224                                 }
 225                                 if (ast_load_resource(v->value)) {
 226                                         ast_log(LOG_WARNING, "Loading module %s failed!\n", v->value);
 227                                         if (cfg)
 228                                                 ast_destroy(cfg);
 229                                         return -1;
 230                                 }
 231                         }
 232                         v=v->next;
 233                 }
 234         }
 235         if (!cfg || ast_true(ast_variable_retrieve(cfg, "modules", "autoload"))) {
 236                 /* Load all modules */
 237                 DIR *mods;
 238                 struct dirent *d;
 239                 mods = opendir(AST_MODULE_DIR);
 240                 if (mods) {
 241                         while((d = readdir(mods))) {
 242                                 /* Must end in .so to load it.  */
 243                                 if ((strlen(d->d_name) > 3) &&
 244                                     !strcasecmp(d->d_name + strlen(d->d_name) - 3, ".so") &&
 245                                         !ast_resource_exists(d->d_name)) {
 246                                         /* It's a shared library -- Just be sure we're allowed to load it -- kinda
 247                                            an inefficient way to do it, but oh well. */
 248                                         if (cfg) {
 249                                                 v = ast_variable_browse(cfg, "modules");
 250                                                 while(v) {
 251                                                         if (!strcasecmp(v->name, "noload") &&
 252                                                             !strcasecmp(v->value, d->d_name))
 253                                                                 break;
 254                                                         v = v->next;
 255                                                 }
 256                                                 if (v) {
 257                                                         if (option_verbose) {
 258                                                                 ast_verbose( VERBOSE_PREFIX_1 "[skipping %s]\n", d->d_name);
 259                                                                 fflush(stdout);
 260                                                         }
 261                                                         continue;
 262                                                 }
 263
 264                                         }
 265                                     if (option_debug && !option_verbose)
 266                                                 ast_log(LOG_DEBUG, "Loading module %s\n", d->d_name);
 267                                         if (option_verbose) {
 268                                                 ast_verbose( VERBOSE_PREFIX_1 "[%s]", d->d_name);
 269                                                 fflush(stdout);
 270                                         }
 271                                         if (ast_load_resource(d->d_name)) {
 272                                                 ast_log(LOG_WARNING, "Loading module %s failed!\n", d->d_name);
 273                                                 if (cfg)
 274                                                         ast_destroy(cfg);
 275                                                 return -1;
 276                                         }
 277                                 }
 278                         };
 279                 } else {
 280                         if (!option_quiet)
 281                                 ast_log(LOG_WARNING, "Unable to open modules directory " AST_MODULE_DIR ".\n");
 282                 }
 283         }
 284         ast_destroy(cfg);
 285         return 0;
 286 }
 287
 288 void ast_update_use_count(void)
 289 {
 290         /* Notify any module monitors that the use count for a
 291            resource has changed */
 292         struct loadupdate *m;
 293         if (pthread_mutex_lock(&modlock))
 294                 ast_log(LOG_WARNING, "Failed to lock\n");
 295         m = updaters;
 296         while(m) {
 297                 m->updater();
 298                 m = m->next;
 299         }
 300         pthread_mutex_unlock(&modlock);
 301
 302 }
 303
 304 int ast_update_module_list(int (*modentry)(char *module, char *description, int usecnt))
 305 {
 306         struct module *m;
 307         int unlock = -1;
 308         if (pthread_mutex_trylock(&modlock))
 309                 unlock = 0;
 310         m = module_list;
 311         while(m) {
 312                 modentry(m->resource, m->description(), m->usecount());
 313                 m = m->next;
 314         }
 315         if (unlock)
 316                 pthread_mutex_unlock(&modlock);
 317         return 0;
 318 }
 319
 320 int ast_loader_register(int (*v)(void))
 321 {
 322         struct loadupdate *tmp;
 323         /* XXX Should be more flexible here, taking > 1 verboser XXX */
 324         if ((tmp = malloc(sizeof (struct loadupdate)))) {
 325                 tmp->updater = v;
 326                 if (pthread_mutex_lock(&modlock))
 327                         ast_log(LOG_WARNING, "Failed to lock\n");
 328                 tmp->next = updaters;
 329                 updaters = tmp;
 330                 pthread_mutex_unlock(&modlock);
 331                 return 0;
 332         }
 333         return -1;
 334 }
 335
 336 int ast_loader_unregister(int (*v)(void))
 337 {
 338         int res = -1;
 339         struct loadupdate *tmp, *tmpl=NULL;
 340         if (pthread_mutex_lock(&modlock))
 341                 ast_log(LOG_WARNING, "Failed to lock\n");
 342         tmp = updaters;
 343         while(tmp) {
 344                 if (tmp->updater == v)  {
 345                         if (tmpl)
 346                                 tmpl->next = tmp->next;
 347                         else
 348                                 updaters = tmp->next;
 349                         break;
 350                 }
 351                 tmpl = tmp;
 352                 tmp = tmp->next;
 353         }
 354         if (tmp)
 355                 res = 0;
 356         pthread_mutex_unlock(&modlock);
 357         return res;
 358 }