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 <babeltrace/types.h>
  37 #include <glib.h>
  38 #include <unistd.h>
  39 #include <stdlib.h>
  40 #include <stdint.h>
  41 #include <sys/stat.h>
  42 #include <dirent.h>
  43
  44 #define PYTHON_PLUGIN_PROVIDER_FILENAME "libbabeltrace-python-plugin-provider." G_MODULE_SUFFIX
  45 #define PYTHON_PLUGIN_PROVIDER_SYM_NAME bt_plugin_python_create_all_from_file
  46 #define PYTHON_PLUGIN_PROVIDER_SYM_NAME_STR     TOSTRING(PYTHON_PLUGIN_PROVIDER_SYM_NAME)
  47
  48 #ifdef BT_BUILT_IN_PYTHON_PLUGIN_SUPPORT
  49 #include <babeltrace/plugin/python-plugin-provider-internal.h>
  50 static
  51 struct bt_plugin_set *(*bt_plugin_python_create_all_from_file_sym)(const char *path) =
  52         bt_plugin_python_create_all_from_file;
  53 #else /* BT_BUILT_IN_PYTHON_PLUGIN_SUPPORT */
  54 static GModule *python_plugin_provider_module;
  55 static
  56 struct bt_plugin_set *(*bt_plugin_python_create_all_from_file_sym)(const char *path);
  57
  58 __attribute__((constructor)) static
  59 void init_python_plugin_provider(void) {
  60         python_plugin_provider_module =
  61                 g_module_open(PYTHON_PLUGIN_PROVIDER_FILENAME,
  62                         G_MODULE_BIND_LOCAL);
  63         if (!python_plugin_provider_module) {
  64                 printf_verbose("Cannot find `%s`: Python plugin support is disabled\n",
  65                         PYTHON_PLUGIN_PROVIDER_FILENAME);
  66                 return;
  67         }
  68
  69         if (!g_module_symbol(python_plugin_provider_module,
  70                         PYTHON_PLUGIN_PROVIDER_SYM_NAME_STR,
  71                         (gpointer) &bt_plugin_python_create_all_from_file_sym)) {
  72                 printf_verbose("Cannot find the Python plugin provider loading symbole: Python plugin support is disabled\n");
  73         }
  74 }
  75
  76 __attribute__((destructor)) static
  77 void fini_python_plugin_provider(void) {
  78         if (python_plugin_provider_module) {
  79                 (void) g_module_close(python_plugin_provider_module);
  80                 python_plugin_provider_module = NULL;
  81         }
  82 }
  83 #endif
  84
  85 extern
  86 int64_t bt_plugin_set_get_plugin_count(struct bt_plugin_set *plugin_set)
  87 {
  88         int64_t count = -1;
  89
  90         if (!plugin_set) {
  91                 goto end;
  92         }
  93
  94         count = (int64_t) plugin_set->plugins->len;
  95
  96 end:
  97         return count;
  98 }
  99
 100 extern
 101 struct bt_plugin *bt_plugin_set_get_plugin(struct bt_plugin_set *plugin_set,
 102                 uint64_t index)
 103 {
 104         struct bt_plugin *plugin = NULL;
 105
 106         if (!plugin_set || index >= plugin_set->plugins->len) {
 107                 goto end;
 108         }
 109
 110         plugin = bt_get(g_ptr_array_index(plugin_set->plugins, index));
 111
 112 end:
 113         return plugin;
 114 }
 115
 116 struct bt_plugin_set *bt_plugin_create_all_from_static(void)
 117 {
 118         return bt_plugin_so_create_all_from_static();
 119 }
 120
 121 struct bt_plugin_set *bt_plugin_create_all_from_file(const char *path)
 122 {
 123         struct bt_plugin_set *plugin_set = NULL;
 124
 125         if (!path) {
 126                 goto end;
 127         }
 128
 129         printf_verbose("Trying to load plugins from `%s`\n", path);
 130
 131         /* Try shared object plugins */
 132         plugin_set = bt_plugin_so_create_all_from_file(path);
 133         if (plugin_set) {
 134                 goto end;
 135         }
 136
 137         /* Try Python plugins if support is available */
 138         if (bt_plugin_python_create_all_from_file_sym) {
 139                 plugin_set = bt_plugin_python_create_all_from_file_sym(path);
 140                 if (plugin_set) {
 141                         goto end;
 142                 }
 143         }
 144
 145 end:
 146         return plugin_set;
 147 }
 148
 149 static void destroy_gstring(void *data)
 150 {
 151         g_string_free(data, TRUE);
 152 }
 153
 154 struct bt_plugin *bt_plugin_find(const char *plugin_name)
 155 {
 156         const char *system_plugin_dir;
 157         char *home_plugin_dir = NULL;
 158         const char *envvar;
 159         struct bt_plugin *plugin = NULL;
 160         struct bt_plugin_set *plugin_set = NULL;
 161         GPtrArray *dirs = NULL;
 162         int ret;
 163         size_t i, j;
 164
 165         if (!plugin_name) {
 166                 goto end;
 167         }
 168
 169         dirs = g_ptr_array_new_with_free_func((GDestroyNotify) destroy_gstring);
 170         if (!dirs) {
 171                 goto end;
 172         }
 173
 174         /*
 175          * Search order is:
 176          *
 177          * 1. BABELTRACE_PLUGIN_PATH environment variable
 178          *    (colon-separated list of directories)
 179          * 2. ~/.local/lib/babeltrace/plugins
 180          * 3. Default system directory for Babeltrace plugins, usually
 181          *    /usr/lib/babeltrace/plugins or
 182          *    /usr/local/lib/babeltrace/plugins if installed
 183          *    locally
 184          * 4. Built-in plugins (static)
 185          *
 186          * Directories are searched non-recursively.
 187          */
 188         envvar = getenv("BABELTRACE_PLUGIN_PATH");
 189         if (envvar) {
 190                 ret = bt_common_append_plugin_path_dirs(envvar, dirs);
 191                 if (ret) {
 192                         goto end;
 193                 }
 194         }
 195
 196         home_plugin_dir = bt_common_get_home_plugin_path();
 197         if (home_plugin_dir) {
 198                 GString *home_plugin_dir_str =
 199                         g_string_new(home_plugin_dir);
 200
 201                 if (!home_plugin_dir_str) {
 202                         goto end;
 203                 }
 204
 205                 g_ptr_array_add(dirs, home_plugin_dir_str);
 206         }
 207
 208         system_plugin_dir = bt_common_get_system_plugin_path();
 209         if (system_plugin_dir) {
 210                 GString *system_plugin_dir_str =
 211                         g_string_new(system_plugin_dir);
 212
 213                 if (!system_plugin_dir_str) {
 214                         goto end;
 215                 }
 216
 217                 g_ptr_array_add(dirs, system_plugin_dir_str);
 218         }
 219
 220         for (i = 0; i < dirs->len; i++) {
 221                 GString *dir = g_ptr_array_index(dirs, i);
 222
 223                 printf_verbose("Trying to load plugins from directory `%s`\n",
 224                         dir->str);
 225                 BT_PUT(plugin_set);
 226                 plugin_set = bt_plugin_create_all_from_dir(dir->str, BT_FALSE);
 227                 if (!plugin_set) {
 228                         continue;
 229                 }
 230
 231                 for (j = 0; j < plugin_set->plugins->len; j++) {
 232                         struct bt_plugin *candidate_plugin =
 233                                 g_ptr_array_index(plugin_set->plugins, j);
 234
 235                         if (strcmp(bt_plugin_get_name(candidate_plugin),
 236                                         plugin_name) == 0) {
 237                                 plugin = bt_get(candidate_plugin);
 238                                 goto end;
 239                         }
 240                 }
 241         }
 242
 243         bt_put(plugin_set);
 244         plugin_set = bt_plugin_create_all_from_static();
 245
 246         for (j = 0; j < plugin_set->plugins->len; j++) {
 247                 struct bt_plugin *candidate_plugin =
 248                         g_ptr_array_index(plugin_set->plugins, j);
 249
 250                 if (strcmp(bt_plugin_get_name(candidate_plugin),
 251                                 plugin_name) == 0) {
 252                         plugin = bt_get(candidate_plugin);
 253                         goto end;
 254                 }
 255         }
 256
 257 end:
 258         free(home_plugin_dir);
 259         bt_put(plugin_set);
 260
 261         if (dirs) {
 262                 g_ptr_array_free(dirs, TRUE);
 263         }
 264
 265         return plugin;
 266 }
 267
 268 struct bt_component_class *bt_plugin_find_component_class(
 269                 const char *plugin_name, const char *comp_cls_name,
 270                 enum bt_component_class_type comp_cls_type)
 271 {
 272         struct bt_plugin *plugin = NULL;
 273         struct bt_component_class *comp_cls = NULL;
 274
 275         if (!plugin_name || !comp_cls_name) {
 276                 goto end;
 277         }
 278
 279         plugin = bt_plugin_find(plugin_name);
 280         if (!plugin) {
 281                 goto end;
 282         }
 283
 284         comp_cls = bt_plugin_get_component_class_by_name_and_type(
 285                 plugin, comp_cls_name, comp_cls_type);
 286
 287 end:
 288         bt_put(plugin);
 289         return comp_cls;
 290 }
 291
 292 /* Allocate dirent as recommended by READDIR(3), NOTES on readdir_r */
 293 static
 294 struct dirent *alloc_dirent(const char *path)
 295 {
 296         size_t len;
 297         long name_max;
 298         struct dirent *entry;
 299
 300         name_max = pathconf(path, _PC_NAME_MAX);
 301         if (name_max == -1) {
 302                 name_max = PATH_MAX;
 303         }
 304         len = offsetof(struct dirent, d_name) + name_max + 1;
 305         entry = zmalloc(len);
 306         return entry;
 307 }
 308
 309 static
 310 enum bt_plugin_status bt_plugin_create_append_all_from_dir(
 311                 struct bt_plugin_set *plugin_set, const char *path,
 312                 bt_bool recurse)
 313 {
 314         DIR *directory = NULL;
 315         struct dirent *entry = NULL, *result = NULL;
 316         char *file_path = NULL;
 317         size_t path_len;
 318         enum bt_plugin_status ret = BT_PLUGIN_STATUS_OK;
 319
 320         if (!path) {
 321                 ret = BT_PLUGIN_STATUS_ERROR;
 322                 goto end;
 323         }
 324
 325         path_len = strlen(path);
 326
 327         if (path_len >= PATH_MAX) {
 328                 ret = BT_PLUGIN_STATUS_ERROR;
 329                 goto end;
 330         }
 331
 332         entry = alloc_dirent(path);
 333         if (!entry) {
 334                 ret = BT_PLUGIN_STATUS_ERROR;
 335                 goto end;
 336         }
 337
 338         file_path = zmalloc(PATH_MAX);
 339         if (!file_path) {
 340                 ret = BT_PLUGIN_STATUS_NOMEM;
 341                 goto end;
 342         }
 343
 344         strncpy(file_path, path, path_len);
 345         /* Append a trailing '/' to the path */
 346         if (file_path[path_len - 1] != '/') {
 347                 file_path[path_len++] = '/';
 348         }
 349
 350         directory = opendir(file_path);
 351         if (!directory) {
 352                 printf_verbose("Failed to open plugin directory \"%s\"\n",
 353                         file_path);
 354                 ret = BT_PLUGIN_STATUS_ERROR;
 355                 goto end;
 356         }
 357
 358         /* Recursively walk directory */
 359         while (!readdir_r(directory, entry, &result) && result) {
 360                 struct stat st;
 361                 int stat_ret;
 362                 size_t file_name_len;
 363
 364                 if (result->d_name[0] == '.') {
 365                         /* Skip hidden files, . and .. */
 366                         continue;
 367                 }
 368
 369                 file_name_len = strlen(result->d_name);
 370
 371                 if (path_len + file_name_len >= PATH_MAX) {
 372                         continue;
 373                 }
 374
 375                 strncpy(file_path + path_len, result->d_name, file_name_len);
 376                 file_path[path_len + file_name_len] = '\0';
 377                 stat_ret = stat(file_path, &st);
 378                 if (stat_ret < 0) {
 379                         /* Continue to next file / directory. */
 380                         printf_perror("Failed to stat() plugin file\n");
 381                         continue;
 382                 }
 383
 384                 if (S_ISDIR(st.st_mode) && recurse) {
 385                         ret = bt_plugin_create_append_all_from_dir(plugin_set,
 386                                 file_path, BT_TRUE);
 387                         if (ret < 0) {
 388                                 goto end;
 389                         }
 390                 } else if (S_ISREG(st.st_mode)) {
 391                         struct bt_plugin_set *plugins_from_file =
 392                                 bt_plugin_create_all_from_file(file_path);
 393
 394                         if (plugins_from_file) {
 395                                 size_t j;
 396
 397                                 for (j = 0; j < plugins_from_file->plugins->len; j++) {
 398                                         struct bt_plugin *plugin =
 399                                                 g_ptr_array_index(plugins_from_file->plugins, j);
 400
 401                                         bt_plugin_set_add_plugin(plugin_set,
 402                                                 plugin);
 403                                 }
 404
 405                                 bt_put(plugins_from_file);
 406                         }
 407                 }
 408         }
 409 end:
 410         if (directory) {
 411                 if (closedir(directory)) {
 412                         /*
 413                          * We don't want to override the error since there is
 414                          * nothing could do.
 415                          */
 416                         perror("Failed to close plug-in directory");
 417                 }
 418         }
 419         free(entry);
 420         free(file_path);
 421         return ret;
 422 }
 423
 424 struct bt_plugin_set *bt_plugin_create_all_from_dir(const char *path,
 425                 bt_bool recurse)
 426 {
 427         struct bt_plugin_set *plugin_set;
 428         enum bt_plugin_status status;
 429
 430         plugin_set = bt_plugin_set_create();
 431         if (!plugin_set) {
 432                 goto error;
 433         }
 434
 435         /* Append found plugins to array */
 436         status = bt_plugin_create_append_all_from_dir(plugin_set, path,
 437                 recurse);
 438         if (status < 0) {
 439                 goto error;
 440         }
 441
 442         goto end;
 443
 444 error:
 445         BT_PUT(plugin_set);
 446
 447 end:
 448         return plugin_set;
 449 }
 450
 451 const char *bt_plugin_get_name(struct bt_plugin *plugin)
 452 {
 453         return plugin && plugin->info.name_set ? plugin->info.name->str : NULL;
 454 }
 455
 456 const char *bt_plugin_get_author(struct bt_plugin *plugin)
 457 {
 458         return plugin && plugin->info.author_set ? plugin->info.author->str : NULL;
 459 }
 460
 461 const char *bt_plugin_get_license(struct bt_plugin *plugin)
 462 {
 463         return plugin && plugin->info.license_set ? plugin->info.license->str : NULL;
 464 }
 465
 466 const char *bt_plugin_get_path(struct bt_plugin *plugin)
 467 {
 468         return plugin && plugin->info.path_set ? plugin->info.path->str : NULL;
 469 }
 470
 471 const char *bt_plugin_get_description(struct bt_plugin *plugin)
 472 {
 473         return plugin && plugin->info.description_set ? plugin->info.description->str : NULL;
 474 }
 475
 476 enum bt_plugin_status bt_plugin_get_version(struct bt_plugin *plugin,
 477                 unsigned int *major, unsigned int *minor, unsigned int *patch,
 478                 const char **extra)
 479 {
 480         enum bt_plugin_status status = BT_PLUGIN_STATUS_OK;
 481
 482         if (!plugin || !plugin->info.version_set) {
 483                 status = BT_PLUGIN_STATUS_ERROR;
 484                 goto end;
 485         }
 486
 487         if (major) {
 488                 *major = plugin->info.version.major;
 489         }
 490
 491         if (minor) {
 492                 *minor = plugin->info.version.minor;
 493         }
 494
 495         if (patch) {
 496                 *patch = plugin->info.version.patch;
 497         }
 498
 499         if (extra) {
 500                 *extra = plugin->info.version.extra->str;
 501         }
 502
 503 end:
 504         return status;
 505 }
 506
 507 int64_t bt_plugin_get_component_class_count(struct bt_plugin *plugin)
 508 {
 509         return plugin ? plugin->comp_classes->len : (int64_t) -1;
 510 }
 511
 512 struct bt_component_class *bt_plugin_get_component_class_by_index(
 513                 struct bt_plugin *plugin, uint64_t index)
 514 {
 515         struct bt_component_class *comp_class = NULL;
 516
 517         if (!plugin || index >= plugin->comp_classes->len) {
 518                 goto error;
 519         }
 520
 521         comp_class = g_ptr_array_index(plugin->comp_classes, index);
 522         bt_get(comp_class);
 523         goto end;
 524
 525 error:
 526         BT_PUT(comp_class);
 527
 528 end:
 529         return comp_class;
 530 }
 531
 532 struct bt_component_class *bt_plugin_get_component_class_by_name_and_type(
 533                 struct bt_plugin *plugin, const char *name,
 534                 enum bt_component_class_type type)
 535 {
 536         struct bt_component_class *comp_class = NULL;
 537         size_t i;
 538
 539         if (!plugin || !name) {
 540                 goto error;
 541         }
 542
 543         for (i = 0; i < plugin->comp_classes->len; i++) {
 544                 struct bt_component_class *comp_class_candidate =
 545                         g_ptr_array_index(plugin->comp_classes, i);
 546                 const char *comp_class_cand_name =
 547                         bt_component_class_get_name(comp_class_candidate);
 548                 enum bt_component_class_type comp_class_cand_type =
 549                         bt_component_class_get_type(comp_class_candidate);
 550
 551                 assert(comp_class_cand_name);
 552                 assert(comp_class_cand_type >= 0);
 553
 554                 if (strcmp(name, comp_class_cand_name) == 0 &&
 555                                 comp_class_cand_type == type) {
 556                         comp_class = bt_get(comp_class_candidate);
 557                         break;
 558                 }
 559         }
 560
 561         goto end;
 562
 563 error:
 564         BT_PUT(comp_class);
 565
 566 end:
 567         return comp_class;
 568 }
 569
 570 enum bt_plugin_status bt_plugin_add_component_class(
 571         struct bt_plugin *plugin, struct bt_component_class *comp_class)
 572 {
 573         enum bt_plugin_status status = BT_PLUGIN_STATUS_OK;
 574         struct bt_component_class *comp_class_dup = NULL;
 575         int comp_class_index = -1;
 576
 577         if (!plugin || !comp_class || plugin->frozen) {
 578                 goto error;
 579         }
 580
 581         /* Check for duplicate */
 582         comp_class_dup = bt_plugin_get_component_class_by_name_and_type(plugin,
 583                 bt_component_class_get_name(comp_class),
 584                 bt_component_class_get_type(comp_class));
 585         if (comp_class_dup) {
 586                 printf_verbose("Plugin `%s`: adding component class with existing name `%s` and type %d\n",
 587                         bt_plugin_get_name(plugin),
 588                         bt_component_class_get_name(comp_class),
 589                         bt_component_class_get_type(comp_class));
 590                 goto error;
 591         }
 592
 593         /* Add new component class */
 594         comp_class_index = plugin->comp_classes->len;
 595         g_ptr_array_add(plugin->comp_classes, bt_get(comp_class));
 596
 597         /* Special case for a shared object plugin */
 598         if (plugin->type == BT_PLUGIN_TYPE_SO) {
 599                 bt_plugin_so_on_add_component_class(plugin, comp_class);
 600         }
 601
 602         goto end;
 603
 604 error:
 605         /* Remove entry from plugin's component classes (if added) */
 606         if (comp_class_index >= 0) {
 607                 g_ptr_array_remove_index(plugin->comp_classes,
 608                         comp_class_index);
 609         }
 610
 611         status = BT_PLUGIN_STATUS_ERROR;
 612
 613 end:
 614         bt_put(comp_class_dup);
 615         return status;
 616 }