lib/plugin/plugin.c

   1 /*
   2  * plugin.c
   3  *
   4  * Babeltrace Plugin (generic)
   5  *
   6  * Copyright 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   7  * Copyright 2017 Philippe Proulx <pproulx@efficios.com>
   8  *
   9  * Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
  10  *
  11  * Permission is hereby granted, free of charge, to any person obtaining a copy
  12  * of this software and associated documentation files (the "Software"), to deal
  13  * in the Software without restriction, including without limitation the rights
  14  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  15  * copies of the Software, and to permit persons to whom the Software is
  16  * furnished to do so, subject to the following conditions:
  17  *
  18  * The above copyright notice and this permission notice shall be included in
  19  * all copies or substantial portions of the Software.
  20  *
  21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  22  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  23  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  24  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  25  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  26  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  27  * SOFTWARE.
  28  */
  29
  30 #include <babeltrace/babeltrace-internal.h>
  31 #include <babeltrace/compiler-internal.h>
  32 #include <babeltrace/ref.h>
  33 #include <babeltrace/common-internal.h>
  34 #include <babeltrace/plugin/plugin-internal.h>
  35 #include <babeltrace/plugin/plugin-so-internal.h>
  36 #include <glib.h>
  37 #include <unistd.h>
  38 #include <stdlib.h>
  39 #include <sys/stat.h>
  40 #include <dirent.h>
  41
  42 #define PYTHON_PLUGIN_PROVIDER_FILENAME "libbabeltrace-python-plugin-provider." G_MODULE_SUFFIX
  43 #define PYTHON_PLUGIN_PROVIDER_SYM_NAME bt_plugin_python_create_all_from_file
  44 #define PYTHON_PLUGIN_PROVIDER_SYM_NAME_STR     TOSTRING(PYTHON_PLUGIN_PROVIDER_SYM_NAME)
  45
  46 #ifdef BT_BUILT_IN_PYTHON_PLUGIN_SUPPORT
  47 #include <babeltrace/plugin/python-plugin-provider-internal.h>
  48 static
  49 struct bt_plugin **(*bt_plugin_python_create_all_from_file_sym)(const char *path) =
  50         bt_plugin_python_create_all_from_file;
  51 #else /* BT_BUILT_IN_PYTHON_PLUGIN_SUPPORT */
  52 static GModule *python_plugin_provider_module;
  53 static
  54 struct bt_plugin **(*bt_plugin_python_create_all_from_file_sym)(const char *path);
  55
  56 __attribute__((constructor)) static
  57 void init_python_plugin_provider(void) {
  58         python_plugin_provider_module =
  59                 g_module_open(PYTHON_PLUGIN_PROVIDER_FILENAME,
  60                         G_MODULE_BIND_LOCAL);
  61         if (!python_plugin_provider_module) {
  62                 printf_warning("Cannot find `%s`: Python plugin support is disabled\n",
  63                         PYTHON_PLUGIN_PROVIDER_FILENAME);
  64                 return;
  65         }
  66
  67         if (!g_module_symbol(python_plugin_provider_module,
  68                         PYTHON_PLUGIN_PROVIDER_SYM_NAME_STR,
  69                         (gpointer) &bt_plugin_python_create_all_from_file_sym)) {
  70                 printf_warning("Cannot find the Python plugin provider loading symbole: Python plugin support is disabled\n");
  71         }
  72 }
  73
  74 __attribute__((destructor)) static
  75 void fini_python_plugin_provider(void) {
  76         if (python_plugin_provider_module) {
  77                 (void) g_module_close(python_plugin_provider_module);
  78                 python_plugin_provider_module = NULL;
  79         }
  80 }
  81 #endif
  82
  83 struct bt_plugin **bt_plugin_create_all_from_static(void)
  84 {
  85         return bt_plugin_so_create_all_from_static();
  86 }
  87
  88 struct bt_plugin **bt_plugin_create_all_from_file(const char *path)
  89 {
  90         struct bt_plugin **plugins = NULL;
  91
  92         if (!path) {
  93                 goto end;
  94         }
  95
  96         printf_verbose("Trying to load plugins from `%s`\n", path);
  97
  98         /* Try shared object plugins */
  99         plugins = bt_plugin_so_create_all_from_file(path);
 100         if (plugins) {
 101                 goto end;
 102         }
 103
 104         /* Try Python plugins if support is available */
 105         if (bt_plugin_python_create_all_from_file_sym) {
 106                 plugins = bt_plugin_python_create_all_from_file_sym(path);
 107                 if (plugins) {
 108                         goto end;
 109                 }
 110         }
 111
 112 end:
 113         return plugins;
 114 }
 115
 116 static void destroy_gstring(void *data)
 117 {
 118         g_string_free(data, TRUE);
 119 }
 120
 121 void free_plugins(struct bt_plugin **plugins) {
 122         if (plugins) {
 123                 struct bt_plugin **cur_plugin = plugins;
 124
 125                 while (*cur_plugin) {
 126                         bt_put(*cur_plugin);
 127                         cur_plugin++;
 128                 }
 129
 130                 free(plugins);
 131         }
 132 }
 133
 134 struct bt_plugin *bt_plugin_find(const char *plugin_name)
 135 {
 136         const char *system_plugin_dir;
 137         char *home_plugin_dir = NULL;
 138         const char *envvar;
 139         struct bt_plugin *plugin = NULL;
 140         struct bt_plugin **plugins = NULL;
 141         struct bt_plugin **cur_plugin;
 142         GPtrArray *dirs = NULL;
 143         int ret;
 144         size_t i;
 145
 146         if (!plugin_name) {
 147                 goto end;
 148         }
 149
 150         dirs = g_ptr_array_new_with_free_func((GDestroyNotify) destroy_gstring);
 151         if (!dirs) {
 152                 goto end;
 153         }
 154
 155         /*
 156          * Search order is:
 157          *
 158          * 1. BABELTRACE_PLUGIN_PATH environment variable
 159          *    (colon-separated list of directories)
 160          * 2. ~/.local/lib/babeltrace/plugins
 161          * 3. Default system directory for Babeltrace plugins, usually
 162          *    /usr/lib/babeltrace/plugins or
 163          *    /usr/local/lib/babeltrace/plugins if installed
 164          *    locally
 165          * 4. Built-in plugins (static)
 166          *
 167          * Directories are searched non-recursively.
 168          */
 169         envvar = getenv("BABELTRACE_PLUGIN_PATH");
 170         if (envvar) {
 171                 ret = bt_common_append_plugin_path_dirs(envvar, dirs);
 172                 if (ret) {
 173                         goto end;
 174                 }
 175         }
 176
 177         home_plugin_dir = bt_common_get_home_plugin_path();
 178         if (home_plugin_dir) {
 179                 GString *home_plugin_dir_str =
 180                         g_string_new(home_plugin_dir);
 181
 182                 if (!home_plugin_dir_str) {
 183                         goto end;
 184                 }
 185
 186                 g_ptr_array_add(dirs, home_plugin_dir_str);
 187         }
 188
 189         system_plugin_dir = bt_common_get_system_plugin_path();
 190         if (system_plugin_dir) {
 191                 GString *system_plugin_dir_str =
 192                         g_string_new(system_plugin_dir);
 193
 194                 if (!system_plugin_dir_str) {
 195                         goto end;
 196                 }
 197
 198                 g_ptr_array_add(dirs, system_plugin_dir_str);
 199         }
 200
 201         for (i = 0; i < dirs->len; i++) {
 202                 GString *dir = g_ptr_array_index(dirs, i);
 203
 204                 printf_verbose("Trying to load plugins from directory `%s`\n",
 205                         dir->str);
 206                 free_plugins(plugins);
 207                 plugins = bt_plugin_create_all_from_dir(dir->str, false);
 208                 if (!plugins) {
 209                         continue;
 210                 }
 211
 212                 cur_plugin = plugins;
 213
 214                 while (*cur_plugin) {
 215                         if (strcmp(bt_plugin_get_name(*cur_plugin), plugin_name)
 216                                         == 0) {
 217                                 plugin = bt_get(*cur_plugin);
 218                                 goto end;
 219                         }
 220
 221                         cur_plugin++;
 222                 }
 223         }
 224
 225         free_plugins(plugins);
 226         plugins = bt_plugin_create_all_from_static();
 227         cur_plugin = plugins;
 228
 229         while (*cur_plugin) {
 230                 if (strcmp(bt_plugin_get_name(*cur_plugin), plugin_name) == 0) {
 231                         plugin = bt_get(*cur_plugin);
 232                         goto end;
 233                 }
 234
 235                 cur_plugin++;
 236         }
 237
 238 end:
 239         free(home_plugin_dir);
 240         free_plugins(plugins);
 241
 242         if (dirs) {
 243                 g_ptr_array_free(dirs, TRUE);
 244         }
 245
 246         return plugin;
 247 }
 248
 249 struct bt_component_class *bt_plugin_find_component_class(
 250                 const char *plugin_name, const char *comp_cls_name,
 251                 enum bt_component_class_type comp_cls_type)
 252 {
 253         struct bt_plugin *plugin = NULL;
 254         struct bt_component_class *comp_cls = NULL;
 255
 256         if (!plugin_name || !comp_cls_name) {
 257                 goto end;
 258         }
 259
 260         plugin = bt_plugin_find(plugin_name);
 261         if (!plugin) {
 262                 goto end;
 263         }
 264
 265         comp_cls = bt_plugin_get_component_class_by_name_and_type(
 266                 plugin, comp_cls_name, comp_cls_type);
 267
 268 end:
 269         bt_put(plugin);
 270         return comp_cls;
 271 }
 272
 273 /* Allocate dirent as recommended by READDIR(3), NOTES on readdir_r */
 274 static
 275 struct dirent *alloc_dirent(const char *path)
 276 {
 277         size_t len;
 278         long name_max;
 279         struct dirent *entry;
 280
 281         name_max = pathconf(path, _PC_NAME_MAX);
 282         if (name_max == -1) {
 283                 name_max = PATH_MAX;
 284         }
 285         len = offsetof(struct dirent, d_name) + name_max + 1;
 286         entry = zmalloc(len);
 287         return entry;
 288 }
 289
 290 static
 291 enum bt_plugin_status bt_plugin_create_append_all_from_dir(
 292                 GPtrArray *plugins, const char *path, bool recurse)
 293 {
 294         DIR *directory = NULL;
 295         struct dirent *entry = NULL, *result = NULL;
 296         char *file_path = NULL;
 297         size_t path_len;
 298         enum bt_plugin_status ret = BT_PLUGIN_STATUS_OK;
 299
 300         if (!path) {
 301                 ret = BT_PLUGIN_STATUS_ERROR;
 302                 goto end;
 303         }
 304
 305         path_len = strlen(path);
 306
 307         if (path_len >= PATH_MAX) {
 308                 ret = BT_PLUGIN_STATUS_ERROR;
 309                 goto end;
 310         }
 311
 312         entry = alloc_dirent(path);
 313         if (!entry) {
 314                 ret = BT_PLUGIN_STATUS_ERROR;
 315                 goto end;
 316         }
 317
 318         file_path = zmalloc(PATH_MAX);
 319         if (!file_path) {
 320                 ret = BT_PLUGIN_STATUS_NOMEM;
 321                 goto end;
 322         }
 323
 324         strncpy(file_path, path, path_len);
 325         /* Append a trailing '/' to the path */
 326         if (file_path[path_len - 1] != '/') {
 327                 file_path[path_len++] = '/';
 328         }
 329
 330         directory = opendir(file_path);
 331         if (!directory) {
 332                 printf_verbose("Failed to open plugin directory \"%s\"\n",
 333                         file_path);
 334                 ret = BT_PLUGIN_STATUS_ERROR;
 335                 goto end;
 336         }
 337
 338         /* Recursively walk directory */
 339         while (!readdir_r(directory, entry, &result) && result) {
 340                 struct stat st;
 341                 int stat_ret;
 342                 size_t file_name_len;
 343
 344                 if (result->d_name[0] == '.') {
 345                         /* Skip hidden files, . and .. */
 346                         continue;
 347                 }
 348
 349                 file_name_len = strlen(result->d_name);
 350
 351                 if (path_len + file_name_len >= PATH_MAX) {
 352                         continue;
 353                 }
 354
 355                 strncpy(file_path + path_len, result->d_name, file_name_len);
 356                 file_path[path_len + file_name_len] = '\0';
 357                 stat_ret = stat(file_path, &st);
 358                 if (stat_ret < 0) {
 359                         /* Continue to next file / directory. */
 360                         printf_perror("Failed to stat() plugin file\n");
 361                         continue;
 362                 }
 363
 364                 if (S_ISDIR(st.st_mode) && recurse) {
 365                         ret = bt_plugin_create_append_all_from_dir(plugins,
 366                                 file_path, true);
 367                         if (ret < 0) {
 368                                 goto end;
 369                         }
 370                 } else if (S_ISREG(st.st_mode)) {
 371                         struct bt_plugin **plugins_from_file =
 372                                 bt_plugin_create_all_from_file(file_path);
 373
 374                         if (plugins_from_file) {
 375                                 struct bt_plugin **plugin;
 376
 377                                 for (plugin = plugins_from_file; *plugin; plugin++) {
 378                                         /* Transfer ownership to array */
 379                                         g_ptr_array_add(plugins, *plugin);
 380                                 }
 381
 382                                 free(plugins_from_file);
 383                         }
 384                 }
 385         }
 386 end:
 387         if (directory) {
 388                 if (closedir(directory)) {
 389                         /*
 390                          * We don't want to override the error since there is
 391                          * nothing could do.
 392                          */
 393                         perror("Failed to close plug-in directory");
 394                 }
 395         }
 396         free(entry);
 397         free(file_path);
 398         return ret;
 399 }
 400
 401 struct bt_plugin **bt_plugin_create_all_from_dir(const char *path,
 402                 bool recurse)
 403 {
 404         GPtrArray *plugins_array = g_ptr_array_new();
 405         struct bt_plugin **plugins = NULL;
 406         enum bt_plugin_status status;
 407
 408         /* Append found plugins to array */
 409         status = bt_plugin_create_append_all_from_dir(plugins_array, path,
 410                 recurse);
 411         if (status < 0) {
 412                 goto error;
 413         }
 414
 415         /* Add sentinel to array */
 416         g_ptr_array_add(plugins_array, NULL);
 417         plugins = (struct bt_plugin **) plugins_array->pdata;
 418         goto end;
 419
 420 error:
 421         if (plugins_array) {
 422                 g_ptr_array_free(plugins_array, TRUE);
 423                 plugins_array = NULL;
 424         }
 425
 426 end:
 427         if (plugins_array) {
 428                 g_ptr_array_free(plugins_array, FALSE);
 429         }
 430
 431         return plugins;
 432 }
 433
 434 const char *bt_plugin_get_name(struct bt_plugin *plugin)
 435 {
 436         return plugin && plugin->info.name_set ? plugin->info.name->str : NULL;
 437 }
 438
 439 const char *bt_plugin_get_author(struct bt_plugin *plugin)
 440 {
 441         return plugin && plugin->info.author_set ? plugin->info.author->str : NULL;
 442 }
 443
 444 const char *bt_plugin_get_license(struct bt_plugin *plugin)
 445 {
 446         return plugin && plugin->info.license_set ? plugin->info.license->str : NULL;
 447 }
 448
 449 const char *bt_plugin_get_path(struct bt_plugin *plugin)
 450 {
 451         return plugin && plugin->info.path_set ? plugin->info.path->str : NULL;
 452 }
 453
 454 const char *bt_plugin_get_description(struct bt_plugin *plugin)
 455 {
 456         return plugin && plugin->info.description_set ? plugin->info.description->str : NULL;
 457 }
 458
 459 enum bt_plugin_status bt_plugin_get_version(struct bt_plugin *plugin,
 460                 unsigned int *major, unsigned int *minor, unsigned int *patch,
 461                 const char **extra)
 462 {
 463         enum bt_plugin_status status = BT_PLUGIN_STATUS_OK;
 464
 465         if (!plugin || !plugin->info.version_set) {
 466                 status = BT_PLUGIN_STATUS_ERROR;
 467                 goto end;
 468         }
 469
 470         if (major) {
 471                 *major = plugin->info.version.major;
 472         }
 473
 474         if (minor) {
 475                 *minor = plugin->info.version.minor;
 476         }
 477
 478         if (patch) {
 479                 *patch = plugin->info.version.patch;
 480         }
 481
 482         if (extra) {
 483                 *extra = plugin->info.version.extra->str;
 484         }
 485
 486 end:
 487         return status;
 488 }
 489
 490 int bt_plugin_get_component_class_count(struct bt_plugin *plugin)
 491 {
 492         return plugin ? plugin->comp_classes->len : -1;
 493 }
 494
 495 struct bt_component_class *bt_plugin_get_component_class(
 496                 struct bt_plugin *plugin, size_t index)
 497 {
 498         struct bt_component_class *comp_class = NULL;
 499
 500         if (!plugin || index >= plugin->comp_classes->len) {
 501                 goto error;
 502         }
 503
 504         comp_class = g_ptr_array_index(plugin->comp_classes, index);
 505         bt_get(comp_class);
 506         goto end;
 507
 508 error:
 509         BT_PUT(comp_class);
 510
 511 end:
 512         return comp_class;
 513 }
 514
 515 struct bt_component_class *bt_plugin_get_component_class_by_name_and_type(
 516                 struct bt_plugin *plugin, const char *name,
 517                 enum bt_component_class_type type)
 518 {
 519         struct bt_component_class *comp_class = NULL;
 520         size_t i;
 521
 522         if (!plugin || !name) {
 523                 goto error;
 524         }
 525
 526         for (i = 0; i < plugin->comp_classes->len; i++) {
 527                 struct bt_component_class *comp_class_candidate =
 528                         g_ptr_array_index(plugin->comp_classes, i);
 529                 const char *comp_class_cand_name =
 530                         bt_component_class_get_name(comp_class_candidate);
 531                 enum bt_component_class_type comp_class_cand_type =
 532                         bt_component_class_get_type(comp_class_candidate);
 533
 534                 assert(comp_class_cand_name);
 535                 assert(comp_class_cand_type >= 0);
 536
 537                 if (strcmp(name, comp_class_cand_name) == 0 &&
 538                                 comp_class_cand_type == type) {
 539                         comp_class = bt_get(comp_class_candidate);
 540                         break;
 541                 }
 542         }
 543
 544         goto end;
 545
 546 error:
 547         BT_PUT(comp_class);
 548
 549 end:
 550         return comp_class;
 551 }
 552
 553 enum bt_plugin_status bt_plugin_add_component_class(
 554         struct bt_plugin *plugin, struct bt_component_class *comp_class)
 555 {
 556         enum bt_plugin_status status = BT_PLUGIN_STATUS_OK;
 557         struct bt_component_class *comp_class_dup = NULL;
 558         int comp_class_index = -1;
 559
 560         if (!plugin || !comp_class || plugin->frozen) {
 561                 goto error;
 562         }
 563
 564         /* Check for duplicate */
 565         comp_class_dup = bt_plugin_get_component_class_by_name_and_type(plugin,
 566                 bt_component_class_get_name(comp_class),
 567                 bt_component_class_get_type(comp_class));
 568         if (comp_class_dup) {
 569                 printf_verbose("Plugin `%s`: adding component class with existing name `%s` and type %d\n",
 570                         bt_plugin_get_name(plugin),
 571                         bt_component_class_get_name(comp_class),
 572                         bt_component_class_get_type(comp_class));
 573                 goto error;
 574         }
 575
 576         /* Add new component class */
 577         comp_class_index = plugin->comp_classes->len;
 578         g_ptr_array_add(plugin->comp_classes, bt_get(comp_class));
 579
 580         /* Special case for a shared object plugin */
 581         if (plugin->type == BT_PLUGIN_TYPE_SO) {
 582                 bt_plugin_so_on_add_component_class(plugin, comp_class);
 583         }
 584
 585         goto end;
 586
 587 error:
 588         /* Remove entry from plugin's component classes (if added) */
 589         if (comp_class_index >= 0) {
 590                 g_ptr_array_remove_index(plugin->comp_classes,
 591                         comp_class_index);
 592         }
 593
 594         status = BT_PLUGIN_STATUS_ERROR;
 595
 596 end:
 597         bt_put(comp_class_dup);
 598         return status;
 599 }