1 /*****************************************************************************
2 * bank.c : Modules list
3 *****************************************************************************
4 * Copyright (C) 2001-2011 VLC authors and VideoLAN
6 * Authors: Sam Hocevar <sam@zoy.org>
7 * Ethan C. Baldridge <BaldridgeE@cadmus.com>
8 * Hans-Peter Jansen <hpj@urpla.net>
9 * Gildas Bazin <gbazin@videolan.org>
10 * RĂ©mi Denis-Courmont
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU Lesser General Public License as published by
14 * the Free Software Foundation; either version 2.1 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Lesser General Public License for more details.
22 * You should have received a copy of the GNU Lesser General Public License
23 * along with this program; if not, write to the Free Software Foundation,
24 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
25 *****************************************************************************/
36 #include <sys/types.h>
42 #include <vlc_common.h>
43 #include <vlc_plugin.h>
44 #include <vlc_modules.h>
47 #include "config/configuration.h"
48 #include "modules/modules.h"
55 } modules = { VLC_STATIC_MUTEX, NULL, 0 };
57 /*****************************************************************************
59 *****************************************************************************/
60 #ifdef HAVE_DYNAMIC_PLUGINS
61 static void AllocateAllPlugins (vlc_object_t *);
63 static module_t *module_InitStatic (vlc_plugin_cb);
65 static void module_StoreBank (module_t *module)
67 /*vlc_assert_locked (&modules.lock);*/
68 module->next = modules.head;
69 modules.head = module;
72 #if defined(__ELF__) || !HAVE_DYNAMIC_PLUGINS
76 # pragma weak vlc_static_modules
78 extern vlc_plugin_cb vlc_static_modules[];
80 static void module_InitStaticModules(void)
82 if (!vlc_static_modules)
85 for (unsigned i = 0; vlc_static_modules[i]; i++) {
86 module_t *module = module_InitStatic (vlc_static_modules[i]);
87 if (likely(module != NULL))
88 module_StoreBank (module);
92 static void module_InitStaticModules(void) { }
98 * Creates a module bank structure which will be filled later
99 * on with all the modules found.
101 void module_InitBank (void)
103 vlc_mutex_lock (&modules.lock);
105 if (modules.usage == 0)
107 /* Fills the module bank structure with the main module infos.
108 * This is very useful as it will allow us to consider the main
109 * library just as another module, and for instance the configuration
110 * options of main will be available in the module bank structure just
111 * as for every other module. */
112 module_t *module = module_InitStatic (vlc_entry__main);
113 if (likely(module != NULL))
114 module_StoreBank (module);
116 module_InitStaticModules();
117 config_SortConfig ();
121 /* We do retain the module bank lock until the plugins are loaded as well.
122 * This is ugly, this staged loading approach is needed: LibVLC gets
123 * some configuration parameters relevant to loading the plugins from
124 * the main (builtin) module. The module bank becomes shared read-only data
125 * once it is ready, so we need to fully serialize initialization.
126 * DO NOT UNCOMMENT the following line unless you managed to squeeze
127 * module_LoadPlugins() before you unlock the mutex. */
128 /*vlc_mutex_unlock (&modules.lock);*/
132 * Unloads all unused plugin modules and empties the module
133 * bank in case of success.
135 void module_EndBank (bool b_plugins)
137 module_t *head = NULL;
139 /* If plugins were _not_ loaded, then the caller still has the bank lock
140 * from module_InitBank(). */
142 vlc_mutex_lock (&modules.lock);
144 vlc_assert_locked (&modules.lock); not for static mutexes :( */
146 assert (modules.usage > 0);
147 if (--modules.usage == 0)
149 config_UnsortConfig ();
153 vlc_mutex_unlock (&modules.lock);
157 module_t *module = head;
160 #ifdef HAVE_DYNAMIC_PLUGINS
161 if (module->b_loaded && module->b_unloadable)
163 module_Unload (module->handle);
164 module->b_loaded = false;
167 vlc_module_destroy (module);
171 #undef module_LoadPlugins
173 * Loads module descriptions for all available plugins.
174 * Fills the module bank structure with the plugin modules.
176 * \param p_this vlc object structure
177 * \return total number of modules in bank after loading all plug-ins
179 size_t module_LoadPlugins (vlc_object_t *obj)
181 /*vlc_assert_locked (&modules.lock); not for static mutexes :( */
183 #ifdef HAVE_DYNAMIC_PLUGINS
184 if (modules.usage == 1)
186 msg_Dbg (obj, "searching plug-in modules");
187 AllocateAllPlugins (obj);
188 config_UnsortConfig ();
189 config_SortConfig ();
192 vlc_mutex_unlock (&modules.lock);
195 module_t **list = module_list_get (&count);
196 module_list_free (list);
197 msg_Dbg (obj, "plug-ins loaded: %zu modules", count);
202 * Frees the flat list of VLC modules.
203 * @param list list obtained by module_list_get()
204 * @param length number of items on the list
207 void module_list_free (module_t **list)
213 * Gets the flat list of VLC modules.
214 * @param n [OUT] pointer to the number of modules
215 * @return table of module pointers (release with module_list_free()),
216 * or NULL in case of error (in that case, *n is zeroed).
218 module_t **module_list_get (size_t *n)
220 /* TODO: this whole module lookup is quite inefficient */
221 /* Remove this and improve module_need */
222 module_t **tab = NULL;
227 for (module_t *mod = modules.head; mod; mod = mod->next)
230 nt = realloc (tab, (i + 1 + mod->submodule_count) * sizeof (*tab));
231 if (unlikely(nt == NULL))
240 for (module_t *subm = mod->submodule; subm; subm = subm->next)
247 #ifdef HAVE_DYNAMIC_PLUGINS
248 typedef enum { CACHE_USE, CACHE_RESET, CACHE_IGNORE } cache_mode_t;
250 static void AllocatePluginPath (vlc_object_t *, const char *, cache_mode_t);
253 * Enumerates all dynamic plug-ins that can be found.
255 * This function will recursively browse the default plug-ins directory and any
256 * directory listed in the VLC_PLUGIN_PATH environment variable.
257 * For performance reasons, a cache is normally used so that plug-in shared
258 * objects do not need to loaded and linked into the process.
260 static void AllocateAllPlugins (vlc_object_t *p_this)
265 if( !var_InheritBool( p_this, "plugins-cache" ) )
267 else if( var_InheritBool( p_this, "reset-plugins-cache" ) )
272 /* Contruct the special search path for system that have a relocatable
273 * executable. Set it to <vlc path>/plugins. */
274 char *vlcpath = config_GetLibDir ();
275 if (likely(vlcpath != NULL)
276 && likely(asprintf (&paths, "%s" DIR_SEP "plugins", vlcpath) != -1))
278 AllocatePluginPath (p_this, paths, mode);
283 /* If the user provided a plugin path, we add it to the list */
284 paths = getenv( "VLC_PLUGIN_PATH" );
288 paths = strdup( paths ); /* don't harm the environment ! :) */
289 if( unlikely(paths == NULL) )
292 for( char *buf, *path = strtok_r( paths, PATH_SEP, &buf );
294 path = strtok_r( NULL, PATH_SEP, &buf ) )
295 AllocatePluginPath (p_this, path, mode);
300 typedef struct module_bank
307 module_cache_t *cache;
310 module_cache_t *loaded_cache;
313 static void AllocatePluginDir (module_bank_t *, unsigned,
314 const char *, const char *);
317 * Scans for plug-ins within a file system hierarchy.
318 * \param path base directory to browse
320 static void AllocatePluginPath (vlc_object_t *p_this, const char *path,
324 module_cache_t *cache = NULL;
330 count = CacheLoad( p_this, path, &cache );
333 CacheDelete( p_this, path );
336 msg_Dbg( p_this, "ignoring plugins cache file" );
339 msg_Dbg( p_this, "recursively browsing `%s'", path );
346 bank.loaded_cache = cache;
347 bank.i_loaded_cache = count;
349 /* Don't go deeper than 5 subdirectories */
350 AllocatePluginDir (&bank, 5, path, NULL);
355 /* Discard unmatched cache entries */
356 for( size_t i = 0; i < count; i++ )
358 if (cache[i].p_module != NULL)
359 vlc_module_destroy (cache[i].p_module);
360 free (cache[i].path);
364 CacheSave (p_this, path, bank.cache, bank.i_cache);
370 static int AllocatePluginFile (module_bank_t *, const char *,
371 const char *, const struct stat *);
374 * Recursively browses a directory to look for plug-ins.
376 static void AllocatePluginDir (module_bank_t *bank, unsigned maxdepth,
377 const char *absdir, const char *reldir)
383 DIR *dh = vlc_opendir (absdir);
387 /* Parse the directory and try to load all files it contains. */
390 char *file = vlc_readdir (dh), *relpath = NULL, *abspath = NULL;
395 if (!strcmp (file, ".") || !strcmp (file, ".."))
398 /* Compute path relative to plug-in base directory */
401 if (asprintf (&relpath, "%s"DIR_SEP"%s", reldir, file) == -1)
405 relpath = strdup (file);
406 if (unlikely(relpath == NULL))
409 /* Compute absolute path */
410 if (asprintf (&abspath, "%s"DIR_SEP"%s", bank->base, relpath) == -1)
417 if (vlc_stat (abspath, &st) == -1)
420 if (S_ISREG (st.st_mode))
422 static const char prefix[] = "lib";
423 static const char suffix[] = "_plugin"LIBEXT;
424 size_t len = strlen (file);
427 /* Check that file matches the "lib*_plugin"LIBEXT pattern */
428 if (len > strlen (suffix)
429 && !strncmp (file, prefix, strlen (prefix))
430 && !strcmp (file + len - strlen (suffix), suffix))
432 /* We load all the files ending with LIBEXT on OS/2,
433 * because OS/2 has a 8.3 length limitation for DLL name */
434 if (len > strlen (LIBEXT)
435 && !strcasecmp (file + len - strlen (LIBEXT), LIBEXT))
437 AllocatePluginFile (bank, abspath, relpath, &st);
439 else if (S_ISDIR (st.st_mode))
440 /* Recurse into another directory */
441 AllocatePluginDir (bank, maxdepth, abspath, relpath);
450 static module_t *module_InitDynamic (vlc_object_t *, const char *, bool);
453 * Scans a plug-in from a file.
455 static int AllocatePluginFile (module_bank_t *bank, const char *abspath,
456 const char *relpath, const struct stat *st)
458 module_t *module = NULL;
460 /* Check our plugins cache first then load plugin if needed */
461 if (bank->mode == CACHE_USE)
463 module = CacheFind (bank->loaded_cache, bank->i_loaded_cache,
467 module->psz_filename = strdup (abspath);
468 if (unlikely(module->psz_filename == NULL))
470 vlc_module_destroy (module);
476 module = module_InitDynamic (bank->obj, abspath, true);
480 /* We have not already scanned and inserted this module */
481 assert (module->next == NULL);
483 /* Unload plugin until we really need it */
484 if (module->b_loaded && module->b_unloadable)
486 module_Unload (module->handle);
487 module->b_loaded = false;
490 /* For now we force loading if the module's config contains callbacks.
491 * Could be optimized by adding an API call.*/
492 for (size_t n = module->confsize, i = 0; i < n; i++)
493 if (module->p_config[i].list_count == 0
494 && (module->p_config[i].list.psz_cb != NULL || module->p_config[i].list.i_cb != NULL))
496 /* !unloadable not allowed for plugins with callbacks */
497 vlc_module_destroy (module);
498 module = module_InitDynamic (bank->obj, abspath, false);
499 if (unlikely(module == NULL))
504 module_StoreBank (module);
506 if (bank->mode != CACHE_IGNORE) /* Add entry to cache */
507 CacheAdd (&bank->cache, &bank->i_cache, relpath, st, module);
508 /* TODO: deal with errors */
513 # define EXTERN_PREFIX "_"
515 # define EXTERN_PREFIX
520 * Loads a dynamically-linked plug-in into memory and initialize it.
522 * The module can then be handled by module_need() and module_unneed().
524 * \param path file path of the shared object
525 * \param fast whether to optimize loading for speed or safety
526 * (fast is used when the plug-in is registered but not used)
528 static module_t *module_InitDynamic (vlc_object_t *obj, const char *path,
531 module_handle_t handle;
533 if (module_Load (obj, path, &handle, fast))
536 /* Try to resolve the symbol */
537 static const char entry_name[] = EXTERN_PREFIX "vlc_entry" MODULE_SUFFIX;
538 vlc_plugin_cb entry =
539 (vlc_plugin_cb) module_Lookup (handle, entry_name);
542 msg_Warn (obj, "cannot find plug-in entry point in %s", path);
546 /* We can now try to call the symbol */
547 module_t *module = vlc_plugin_describe (entry);
548 if (unlikely(module == NULL))
550 /* With a well-written module we shouldn't have to print an
551 * additional error message here, but just make sure. */
552 msg_Err (obj, "cannot initialize plug-in %s", path);
556 module->psz_filename = strdup (path);
557 if (unlikely(module->psz_filename == NULL))
559 vlc_module_destroy (module);
562 module->handle = handle;
563 module->b_loaded = true;
566 module_Unload( handle );
569 #endif /* HAVE_DYNAMIC_PLUGINS */
572 * Registers a statically-linked plug-in.
574 static module_t *module_InitStatic (vlc_plugin_cb entry)
576 /* Initializes the module */
577 module_t *module = vlc_plugin_describe (entry);
578 if (unlikely(module == NULL))
581 module->b_loaded = true;
582 module->b_unloadable = false;
587 * Makes sure the module is loaded in memory.
588 * \return 0 on success, -1 on failure
590 int module_Map (vlc_object_t *obj, module_t *module)
592 if (module->parent != NULL)
593 module = module->parent;
595 #warning FIXME: race condition!
596 if (module->b_loaded)
598 assert (module->psz_filename != NULL);
600 #ifdef HAVE_DYNAMIC_PLUGINS
601 module_t *uncache = module_InitDynamic (obj, module->psz_filename, false);
604 CacheMerge (obj, module, uncache);
605 vlc_module_destroy (uncache);
609 msg_Err (obj, "corrupt module: %s", module->psz_filename);