loader.c

   1 /*
   2  * Asterisk -- A telephony toolkit for Linux.
   3  *
   4  * Module Loader
   5  *
   6  * Copyright (C) 1999, Adtran Inc. and Linux Support Services, LLC
   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 = malloc(sizeof(struct module));
  95         if (!m) {
  96                 ast_log(LOG_WARNING, "Out of memory\n");
  97                 return -1;
  98         }
  99         strncpy(m->resource, resource_name, sizeof(m->resource));
 100         if (resource_name[0] == '/') {
 101                 strncpy(fn, resource_name, sizeof(fn));
 102         } else {
 103                 snprintf(fn, sizeof(fn), "%s/%s", AST_MODULE_DIR, resource_name);
 104         }
 105         m->lib = dlopen(fn, RTLD_NOW  | RTLD_GLOBAL);
 106         if (!m->lib) {
 107                 ast_log(LOG_WARNING, "%s\n", dlerror());
 108                 free(m);
 109                 return -1;
 110         }
 111         m->load_module = dlsym(m->lib, "load_module");
 112         if (!m->load_module) {
 113                 ast_log(LOG_WARNING, "No load_module in module %s\n", fn);
 114                 errors++;
 115         }
 116         m->unload_module = dlsym(m->lib, "unload_module");
 117         if (!m->unload_module) {
 118                 ast_log(LOG_WARNING, "No unload_module in module %s\n", fn);
 119                 errors++;
 120         }
 121         m->usecount = dlsym(m->lib, "usecount");
 122         if (!m->usecount) {
 123                 ast_log(LOG_WARNING, "No usecount in module %s\n", fn);
 124                 errors++;
 125         }
 126         m->description = dlsym(m->lib, "description");
 127         if (!m->description) {
 128                 ast_log(LOG_WARNING, "No description in module %s\n", fn);
 129                 errors++;
 130         }
 131         if (errors) {
 132                 ast_log(LOG_WARNING, "%d error(s) loading module %s, aborted\n", errors, fn);
 133                 dlclose(m->lib);
 134                 free(m);
 135                 return -1;
 136         }
 137         if (option_verbose)
 138                 ast_verbose( " => (%s)\n", m->description());
 139         if ((res = m->load_module())) {
 140                 ast_log(LOG_WARNING, "%s: load_module failed, returning %d\n", m->resource, fn, res);
 141                 free(m);
 142                 return -1;
 143         }
 144         if (pthread_mutex_lock(&modlock))
 145                 ast_log(LOG_WARNING, "Failed to lock\n");
 146         m->next = module_list;
 147         module_list = m;
 148         pthread_mutex_unlock(&modlock);
 149         ast_update_use_count();
 150         return 0;
 151 }
 152
 153 int ast_resource_exists(char *resource)
 154 {
 155         struct module *m;
 156         if (pthread_mutex_lock(&modlock))
 157                 ast_log(LOG_WARNING, "Failed to lock\n");
 158         m = module_list;
 159         while(m) {
 160                 if (!strcasecmp(resource, m->resource))
 161                         break;
 162                 m = m->next;
 163         }
 164         pthread_mutex_unlock(&modlock);
 165         if (m)
 166                 return -1;
 167         else
 168                 return 0;
 169 }
 170
 171 int load_modules()
 172 {
 173         struct ast_config *cfg;
 174         struct ast_variable *v;
 175         if (option_verbose)
 176                 ast_verbose( "Asterisk Dynamic Loader Starting:\n");
 177         cfg = ast_load(AST_MODULE_CONFIG);
 178         if (cfg) {
 179                 /* Load explicitly defined modules */
 180                 v = ast_variable_browse(cfg, "modules");
 181                 while(v) {
 182                         if (!strcasecmp(v->name, "load")) {
 183                                 if (option_debug && !option_verbose)
 184                                         ast_log(LOG_DEBUG, "Loading module %s\n", v->value);
 185                                 if (option_verbose) {
 186                                         ast_verbose( " [%s]", v->value);
 187                                         fflush(stdout);
 188                                 }
 189                                 if (ast_load_resource(v->value)) {
 190                                         ast_log(LOG_WARNING, "Loading module %s failed!\n", v->value);
 191                                         if (cfg)
 192                                                 ast_destroy(cfg);
 193                                         return -1;
 194                                 }
 195                         }
 196                         v=v->next;
 197                 }
 198         }
 199         if (!cfg || ast_true(ast_variable_retrieve(cfg, "modules", "autoload"))) {
 200                 /* Load all modules */
 201                 DIR *mods;
 202                 struct dirent *d;
 203                 mods = opendir(AST_MODULE_DIR);
 204                 if (mods) {
 205                         while((d = readdir(mods))) {
 206                                 /* Must end in .so to load it.  */
 207                                 if ((strlen(d->d_name) > 3) &&
 208                                     !strcasecmp(d->d_name + strlen(d->d_name) - 3, ".so") &&
 209                                         !ast_resource_exists(d->d_name)) {
 210                                         /* It's a shared library -- Just be sure we're allowed to load it -- kinda
 211                                            an inefficient way to do it, but oh well. */
 212                                         if (cfg) {
 213                                                 v = ast_variable_browse(cfg, "modules");
 214                                                 while(v) {
 215                                                         if (!strcasecmp(v->name, "noload") &&
 216                                                             !strcasecmp(v->value, d->d_name))
 217                                                                 break;
 218                                                         v = v->next;
 219                                                 }
 220                                                 if (v) {
 221                                                         if (option_verbose) {
 222                                                                 ast_verbose( VERBOSE_PREFIX_1 "[skipping %s]\n", d->d_name);
 223                                                                 fflush(stdout);
 224                                                         }
 225                                                         continue;
 226                                                 }
 227
 228                                         }
 229                                     if (option_debug && !option_verbose)
 230                                                 ast_log(LOG_DEBUG, "Loading module %s\n", d->d_name);
 231                                         if (option_verbose) {
 232                                                 ast_verbose( VERBOSE_PREFIX_1 "[%s]", d->d_name);
 233                                                 fflush(stdout);
 234                                         }
 235                                         if (ast_load_resource(d->d_name)) {
 236                                                 ast_log(LOG_WARNING, "Loading module %s failed!\n", d->d_name);
 237                                                 if (cfg)
 238                                                         ast_destroy(cfg);
 239                                                 return -1;
 240                                         }
 241                                 }
 242                         };
 243                 } else {
 244                         if (!option_quiet)
 245                                 ast_log(LOG_WARNING, "Unable to open modules directory " AST_MODULE_DIR ".\n");
 246                 }
 247         }
 248         ast_destroy(cfg);
 249         return 0;
 250 }
 251
 252 void ast_update_use_count(void)
 253 {
 254         /* Notify any module monitors that the use count for a
 255            resource has changed */
 256         struct loadupdate *m;
 257         if (pthread_mutex_lock(&modlock))
 258                 ast_log(LOG_WARNING, "Failed to lock\n");
 259         m = updaters;
 260         while(m) {
 261                 m->updater();
 262                 m = m->next;
 263         }
 264         pthread_mutex_unlock(&modlock);
 265
 266 }
 267
 268 int ast_update_module_list(int (*modentry)(char *module, char *description, int usecnt))
 269 {
 270         struct module *m;
 271         int unlock = -1;
 272         if (pthread_mutex_trylock(&modlock))
 273                 unlock = 0;
 274         m = module_list;
 275         while(m) {
 276                 modentry(m->resource, m->description(), m->usecount());
 277                 m = m->next;
 278         }
 279         if (unlock)
 280                 pthread_mutex_unlock(&modlock);
 281         return 0;
 282 }
 283
 284 int ast_loader_register(int (*v)(void))
 285 {
 286         struct loadupdate *tmp;
 287         /* XXX Should be more flexible here, taking > 1 verboser XXX */
 288         if ((tmp = malloc(sizeof (struct loadupdate)))) {
 289                 tmp->updater = v;
 290                 if (pthread_mutex_lock(&modlock))
 291                         ast_log(LOG_WARNING, "Failed to lock\n");
 292                 tmp->next = updaters;
 293                 updaters = tmp;
 294                 pthread_mutex_unlock(&modlock);
 295                 return 0;
 296         }
 297         return -1;
 298 }
 299
 300 int ast_loader_unregister(int (*v)(void))
 301 {
 302         int res = -1;
 303         struct loadupdate *tmp, *tmpl=NULL;
 304         if (pthread_mutex_lock(&modlock))
 305                 ast_log(LOG_WARNING, "Failed to lock\n");
 306         tmp = updaters;
 307         while(tmp) {
 308                 if (tmp->updater == v)  {
 309                         if (tmpl)
 310                                 tmpl->next = tmp->next;
 311                         else
 312                                 updaters = tmp->next;
 313                         break;
 314                 }
 315                 tmpl = tmp;
 316                 tmp = tmp->next;
 317         }
 318         if (tmp)
 319                 res = 0;
 320         pthread_mutex_unlock(&modlock);
 321         return res;
 322 }