| 1 | |
| 2 | /* This file is part of the Linux Trace Toolkit viewer |
| 3 | * Copyright (C) 2003-2004 Michel Dagenais |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License Version 2 as |
| 7 | * published by the Free Software Foundation; |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; if not, write to the Free Software |
| 16 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 17 | * MA 02111-1307, USA. |
| 18 | */ |
| 19 | |
| 20 | |
| 21 | /* module.c : Implementation of the module loading/unloading mechanism. */ |
| 22 | |
| 23 | #include <lttv/module.h> |
| 24 | #include <gmodule.h> |
| 25 | |
| 26 | |
| 27 | struct _LttvLibrary |
| 28 | { |
| 29 | LttvLibraryInfo info; |
| 30 | GPtrArray *modules; |
| 31 | GModule *gm; |
| 32 | guint locked_loaded; |
| 33 | }; |
| 34 | |
| 35 | |
| 36 | struct _LttvModule |
| 37 | { |
| 38 | LttvModuleInfo info; |
| 39 | char **prerequisites_names; |
| 40 | GPtrArray *prerequisites; |
| 41 | }; |
| 42 | |
| 43 | |
| 44 | /* Modules are searched by name. However, a library may be loaded which |
| 45 | provides a module with the same name as an existing one. A stack of |
| 46 | modules is thus maintained for each name. |
| 47 | |
| 48 | Libraries correspond to glib modules. The g_module function is |
| 49 | responsible for loading each library only once. */ |
| 50 | |
| 51 | static GHashTable *modules_by_name = NULL; |
| 52 | |
| 53 | static GPtrArray *libraries = NULL; |
| 54 | |
| 55 | static GHashTable *libraries_by_g_module = NULL; |
| 56 | |
| 57 | static GPtrArray *library_paths = NULL; |
| 58 | |
| 59 | static gboolean initialized = FALSE; |
| 60 | |
| 61 | static gboolean destroyed = TRUE; |
| 62 | |
| 63 | static struct _LttvModuleDescription *builtin_chain = NULL; |
| 64 | |
| 65 | static struct _LttvModuleDescription *module_chain = NULL; |
| 66 | |
| 67 | static struct _LttvModuleDescription **module_next = &module_chain; |
| 68 | |
| 69 | static GQuark lttv_module_error; |
| 70 | |
| 71 | static void init(); |
| 72 | |
| 73 | static finish_destroy(); |
| 74 | |
| 75 | static void module_release(LttvModule *m); |
| 76 | |
| 77 | |
| 78 | static LttvLibrary *library_add(char *name, char *path, GModule *gm) |
| 79 | { |
| 80 | LttvLibrary *l; |
| 81 | |
| 82 | LttvModule *m; |
| 83 | |
| 84 | struct _LttvModuleDescription *link; |
| 85 | |
| 86 | GPtrArray *modules; |
| 87 | |
| 88 | l = g_new(LttvLibrary, 1); |
| 89 | l->modules = g_ptr_array_new(); |
| 90 | l->gm = gm; |
| 91 | l->locked_loaded = 0; |
| 92 | l->info.name = g_strdup(name); |
| 93 | l->info.path = g_strdup(path); |
| 94 | l->info.load_count = 0; |
| 95 | |
| 96 | g_ptr_array_add(libraries, l); |
| 97 | g_hash_table_insert(libraries_by_g_module, gm, l); |
| 98 | |
| 99 | *module_next = NULL; |
| 100 | for(link = module_chain; link != NULL; link = link->next) { |
| 101 | m = g_new(LttvModule, 1); |
| 102 | g_ptr_array_add(l->modules, m); |
| 103 | |
| 104 | modules = g_hash_table_lookup(modules_by_name, link->name); |
| 105 | if(modules == NULL) { |
| 106 | modules = g_ptr_array_new(); |
| 107 | g_hash_table_insert(modules_by_name, g_strdup(link->name), modules); |
| 108 | } |
| 109 | g_ptr_array_add(modules, m); |
| 110 | |
| 111 | m->prerequisites_names = link->prerequisites; |
| 112 | m->prerequisites = g_ptr_array_new(); |
| 113 | m->info.name = link->name; |
| 114 | m->info.short_description = link->short_description; |
| 115 | m->info.description = link->description; |
| 116 | m->info.init = link->init; |
| 117 | m->info.destroy = link->destroy; |
| 118 | m->info.library = l; |
| 119 | m->info.require_count = 0; |
| 120 | m->info.use_count = 0; |
| 121 | m->info.prerequisites_number = link->prerequisites_number; |
| 122 | } |
| 123 | return l; |
| 124 | } |
| 125 | |
| 126 | |
| 127 | static void library_remove(LttvLibrary *l) |
| 128 | { |
| 129 | LttvModule *m; |
| 130 | |
| 131 | GPtrArray *modules; |
| 132 | |
| 133 | guint i; |
| 134 | |
| 135 | char *key; |
| 136 | |
| 137 | for(i = 0 ; i < l->modules->len ; i++) { |
| 138 | m = (LttvModule *)(l->modules->pdata[i]); |
| 139 | |
| 140 | g_hash_table_lookup_extended(modules_by_name, m->info.name, |
| 141 | (gpointer *)&key, (gpointer *)&modules); |
| 142 | g_assert(modules != NULL); |
| 143 | g_ptr_array_remove(modules, m); |
| 144 | if(modules->len == 0) { |
| 145 | g_hash_table_remove(modules_by_name, m->info.name); |
| 146 | g_ptr_array_free(modules, TRUE); |
| 147 | g_free(key); |
| 148 | } |
| 149 | |
| 150 | g_ptr_array_free(m->prerequisites, TRUE); |
| 151 | g_free(m); |
| 152 | } |
| 153 | |
| 154 | g_ptr_array_remove(libraries, l); |
| 155 | g_hash_table_remove(libraries_by_g_module, l->gm); |
| 156 | g_ptr_array_free(l->modules, TRUE); |
| 157 | g_free(l->info.name); |
| 158 | g_free(l->info.path); |
| 159 | g_free(l); |
| 160 | } |
| 161 | |
| 162 | |
| 163 | static LttvLibrary *library_load(char *name, GError **error) |
| 164 | { |
| 165 | GModule *gm; |
| 166 | |
| 167 | int i, nb; |
| 168 | |
| 169 | char *path, *pathname; |
| 170 | |
| 171 | LttvLibrary *l; |
| 172 | |
| 173 | GString *messages = g_string_new(""); |
| 174 | |
| 175 | /* insure that module.c is initialized */ |
| 176 | |
| 177 | init(); |
| 178 | |
| 179 | /* Try to find the library along all the user specified paths */ |
| 180 | |
| 181 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Load library %s", name); |
| 182 | nb = lttv_library_path_number(); |
| 183 | for(i = 0 ; i <= nb ; i++) { |
| 184 | if(i < nb) path = lttv_library_path_get(i); |
| 185 | else path = NULL; |
| 186 | |
| 187 | pathname = g_module_build_path(path ,name); |
| 188 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Try path %s", pathname); |
| 189 | module_chain = NULL; |
| 190 | module_next = &module_chain; |
| 191 | gm = g_module_open(pathname,0); |
| 192 | g_free(pathname); |
| 193 | |
| 194 | if(gm != NULL) break; |
| 195 | |
| 196 | g_string_append(messages, g_module_error()); |
| 197 | g_string_append(messages, "\n"); |
| 198 | g_log(G_LOG_DOMAIN,G_LOG_LEVEL_INFO,"Trial failed, %s", g_module_error()); |
| 199 | } |
| 200 | |
| 201 | /* Module cannot be found */ |
| 202 | |
| 203 | if(gm == NULL) { |
| 204 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Failed to load %s", name); |
| 205 | g_set_error(error, lttv_module_error, LTTV_MODULE_NOT_FOUND, |
| 206 | "Cannot load library %s: %s", name, messages->str); |
| 207 | g_string_free(messages, TRUE); |
| 208 | return NULL; |
| 209 | } |
| 210 | g_string_free(messages, TRUE); |
| 211 | |
| 212 | /* Check if the library was already loaded */ |
| 213 | |
| 214 | l = g_hash_table_lookup(libraries_by_g_module, gm); |
| 215 | |
| 216 | /* This library was not already loaded */ |
| 217 | |
| 218 | if(l == NULL) { |
| 219 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Library %s (%s) loaded", name, |
| 220 | g_module_name(gm)); |
| 221 | l = library_add(name, path, gm); |
| 222 | } |
| 223 | return l; |
| 224 | } |
| 225 | |
| 226 | |
| 227 | LttvLibrary *lttv_library_load(char *name, GError **error) |
| 228 | { |
| 229 | LttvLibrary *l = library_load(name, error); |
| 230 | l->info.load_count++; |
| 231 | return l; |
| 232 | } |
| 233 | |
| 234 | |
| 235 | static void library_unload(LttvLibrary *l) |
| 236 | { |
| 237 | guint i, len; |
| 238 | |
| 239 | GModule *gm; |
| 240 | |
| 241 | LttvModule *m; |
| 242 | |
| 243 | if(l->locked_loaded > 0) { |
| 244 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload library %s: locked loaded", |
| 245 | l->info.name); |
| 246 | return; |
| 247 | } |
| 248 | |
| 249 | if(l->info.load_count > 0) { |
| 250 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload library %s: load count %d", |
| 251 | l->info.name, l->info.load_count); |
| 252 | return; |
| 253 | } |
| 254 | |
| 255 | /* Check if all its modules have been released */ |
| 256 | |
| 257 | for(i = 0 ; i < l->modules->len ; i++) { |
| 258 | m = (LttvModule *)(l->modules->pdata[i]); |
| 259 | if(m->info.use_count > 0) { |
| 260 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO,"Unload library %s: module %s used", |
| 261 | l->info.name, m->info.name); |
| 262 | return; |
| 263 | } |
| 264 | } |
| 265 | |
| 266 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload library %s: close the GModule", |
| 267 | l->info.name); |
| 268 | gm = l->gm; |
| 269 | library_remove(l); |
| 270 | if(gm != NULL) g_module_close(gm); |
| 271 | |
| 272 | /* insure that module.c will be finalized */ |
| 273 | |
| 274 | finish_destroy(); |
| 275 | } |
| 276 | |
| 277 | |
| 278 | void lttv_library_unload(LttvLibrary *l) |
| 279 | { |
| 280 | l->info.load_count--; |
| 281 | library_unload(l); |
| 282 | } |
| 283 | |
| 284 | |
| 285 | static void library_lock_loaded(LttvLibrary *l) |
| 286 | { |
| 287 | l->locked_loaded++; |
| 288 | } |
| 289 | |
| 290 | |
| 291 | static void library_unlock_loaded(LttvLibrary *l) |
| 292 | { |
| 293 | l->locked_loaded--; |
| 294 | library_unload(l); |
| 295 | } |
| 296 | |
| 297 | |
| 298 | static LttvModule *module_require(char *name, GError **error) |
| 299 | { |
| 300 | GError *tmp_error = NULL; |
| 301 | |
| 302 | guint i, j; |
| 303 | |
| 304 | LttvModule *m, *required; |
| 305 | |
| 306 | LttvLibrary *l = NULL; |
| 307 | |
| 308 | GPtrArray *modules; |
| 309 | |
| 310 | /* Insure that module.c is initialized */ |
| 311 | |
| 312 | init(); |
| 313 | |
| 314 | /* Check if the module is already loaded */ |
| 315 | |
| 316 | modules = g_hash_table_lookup(modules_by_name, name); |
| 317 | |
| 318 | /* Try to load a library having the module name */ |
| 319 | |
| 320 | if(modules == NULL) { |
| 321 | l = library_load(name, error); |
| 322 | if(l == NULL) return NULL; |
| 323 | else library_lock_loaded(l); |
| 324 | |
| 325 | /* A library was found, does it contain the named module */ |
| 326 | |
| 327 | modules = g_hash_table_lookup(modules_by_name, name); |
| 328 | if(modules == NULL) { |
| 329 | g_set_error(error, lttv_module_error, LTTV_MODULE_NOT_FOUND, |
| 330 | "Module %s not found in library %s", name, l->info.name); |
| 331 | library_unlock_loaded(l); |
| 332 | return NULL; |
| 333 | } |
| 334 | } |
| 335 | m = (LttvModule *)(modules->pdata[modules->len - 1]); |
| 336 | |
| 337 | /* We have the module */ |
| 338 | |
| 339 | m->info.use_count++; |
| 340 | |
| 341 | /* First use of the module. Initialize after getting the prerequisites */ |
| 342 | |
| 343 | if(m->info.use_count == 1) { |
| 344 | for(i = 0 ; i < m->info.prerequisites_number ; i++) { |
| 345 | required = module_require(m->prerequisites_names[i], &tmp_error); |
| 346 | |
| 347 | /* A prerequisite could not be found, undo everything and fail */ |
| 348 | |
| 349 | if(required == NULL) { |
| 350 | for(j = 0 ; j < m->prerequisites->len ; j++) { |
| 351 | module_release((LttvModule *)(m->prerequisites->pdata[j])); |
| 352 | } |
| 353 | g_ptr_array_set_size(m->prerequisites, 0); |
| 354 | if(l != NULL) library_unlock_loaded(l); |
| 355 | g_set_error(error, lttv_module_error, LTTV_MODULE_NOT_FOUND, |
| 356 | "Cannot find prerequisite for module %s: %s", name, |
| 357 | tmp_error->message); |
| 358 | g_clear_error(&tmp_error); |
| 359 | return NULL; |
| 360 | } |
| 361 | g_ptr_array_add(m->prerequisites, required); |
| 362 | } |
| 363 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Module %s: init()", m->info.name); |
| 364 | m->info.init(); |
| 365 | } |
| 366 | |
| 367 | /* Decrement the load count of the library. It will not really be |
| 368 | unloaded since it contains a currently used module. */ |
| 369 | |
| 370 | if(l != NULL) library_unlock_loaded(l); |
| 371 | |
| 372 | return(m); |
| 373 | } |
| 374 | |
| 375 | |
| 376 | /* The require_count for a module is the number of explicit calls to |
| 377 | lttv_module_require, while the use_count also counts the number of times |
| 378 | a module is needed as a prerequisite. */ |
| 379 | |
| 380 | LttvModule *lttv_module_require(char *name, GError **error) |
| 381 | { |
| 382 | LttvModule *m = module_require(name, error); |
| 383 | if(m != NULL) m->info.require_count++; |
| 384 | return(m); |
| 385 | } |
| 386 | |
| 387 | |
| 388 | static void module_release(LttvModule *m) |
| 389 | { |
| 390 | guint i; |
| 391 | |
| 392 | library_lock_loaded(m->info.library); |
| 393 | |
| 394 | m->info.use_count--; |
| 395 | if(m->info.use_count == 0) { |
| 396 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Module %s: destroy()",m->info.name); |
| 397 | m->info.destroy(); |
| 398 | for(i = 0 ; i < m->prerequisites->len ; i++) { |
| 399 | module_release((LttvModule *)(m->prerequisites->pdata[i])); |
| 400 | } |
| 401 | g_ptr_array_set_size(m->prerequisites, 0); |
| 402 | } |
| 403 | library_unlock_loaded(m->info.library); |
| 404 | } |
| 405 | |
| 406 | |
| 407 | void lttv_module_release(LttvModule *m) |
| 408 | { |
| 409 | m->info.require_count--; |
| 410 | module_release(m); |
| 411 | } |
| 412 | |
| 413 | |
| 414 | void lttv_module_info(LttvModule *m, LttvModuleInfo *info) |
| 415 | { |
| 416 | *info = m->info; |
| 417 | } |
| 418 | |
| 419 | |
| 420 | unsigned lttv_module_prerequisite_number(LttvModule *m) |
| 421 | { |
| 422 | return m->prerequisites->len; |
| 423 | } |
| 424 | |
| 425 | |
| 426 | LttvModule *lttv_module_prerequisite_get(LttvModule *m, unsigned i) |
| 427 | { |
| 428 | return (LttvModule *)(m->prerequisites->pdata[i]); |
| 429 | } |
| 430 | |
| 431 | |
| 432 | void lttv_library_info(LttvLibrary *l, LttvLibraryInfo *info) |
| 433 | { |
| 434 | *info = l->info; |
| 435 | } |
| 436 | |
| 437 | |
| 438 | unsigned lttv_library_module_number(LttvLibrary *l) |
| 439 | { |
| 440 | return l->modules->len; |
| 441 | } |
| 442 | |
| 443 | |
| 444 | LttvModule *lttv_library_module_get(LttvLibrary *l, unsigned i) |
| 445 | { |
| 446 | return (LttvModule *)(l->modules->pdata[i]); |
| 447 | } |
| 448 | |
| 449 | |
| 450 | unsigned lttv_library_number() |
| 451 | { |
| 452 | return libraries->len; |
| 453 | } |
| 454 | |
| 455 | |
| 456 | LttvLibrary *lttv_library_get(unsigned i) |
| 457 | { |
| 458 | return (LttvLibrary *)(libraries->pdata[i]); |
| 459 | } |
| 460 | |
| 461 | |
| 462 | void lttv_library_path_add(char *name) |
| 463 | { |
| 464 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Add library path %s", name); |
| 465 | g_ptr_array_add(library_paths,(char*)g_strdup(name)); |
| 466 | } |
| 467 | |
| 468 | |
| 469 | void lttv_library_path_remove(char *name) |
| 470 | { |
| 471 | guint i; |
| 472 | |
| 473 | for(i = 0 ; i < library_paths->len ; i++) { |
| 474 | if(g_str_equal(name, library_paths->pdata[i])) { |
| 475 | g_free(library_paths->pdata[i]); |
| 476 | g_ptr_array_remove_index(library_paths,i); |
| 477 | return; |
| 478 | } |
| 479 | } |
| 480 | } |
| 481 | |
| 482 | |
| 483 | unsigned lttv_library_path_number() |
| 484 | { |
| 485 | return library_paths->len; |
| 486 | } |
| 487 | |
| 488 | |
| 489 | char *lttv_library_path_get(unsigned i) |
| 490 | { |
| 491 | return (char *)(library_paths->pdata[library_paths->len - i - 1]); |
| 492 | } |
| 493 | |
| 494 | |
| 495 | void lttv_module_register(struct _LttvModuleDescription *d) |
| 496 | { |
| 497 | *module_next = d; |
| 498 | module_next = &(d->next); |
| 499 | } |
| 500 | |
| 501 | |
| 502 | static void init() |
| 503 | { |
| 504 | if(initialized) return; |
| 505 | g_assert(destroyed); |
| 506 | |
| 507 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Init module.c"); |
| 508 | |
| 509 | initialized = TRUE; |
| 510 | destroyed = FALSE; |
| 511 | lttv_module_error = g_quark_from_string("LTTV_MODULE_ERROR"); |
| 512 | modules_by_name = g_hash_table_new(g_str_hash, g_str_equal); |
| 513 | libraries = g_ptr_array_new(); |
| 514 | libraries_by_g_module = g_hash_table_new(g_direct_hash, g_direct_equal); |
| 515 | library_paths = g_ptr_array_new(); |
| 516 | |
| 517 | if(builtin_chain == NULL) builtin_chain = module_chain; |
| 518 | module_chain = builtin_chain; |
| 519 | library_add("builtin", NULL, NULL); |
| 520 | } |
| 521 | |
| 522 | |
| 523 | static finish_destroy() |
| 524 | { |
| 525 | guint i; |
| 526 | |
| 527 | if(initialized) return; |
| 528 | g_assert(!destroyed); |
| 529 | |
| 530 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Finish destroy module.c"); |
| 531 | g_hash_table_destroy(modules_by_name); |
| 532 | g_ptr_array_free(libraries, TRUE); |
| 533 | g_hash_table_destroy(libraries_by_g_module); |
| 534 | for(i = 0 ; i < library_paths->len ; i++) { |
| 535 | g_free(library_paths->pdata[i]); |
| 536 | } |
| 537 | g_ptr_array_free(library_paths, TRUE); |
| 538 | destroyed = TRUE; |
| 539 | } |
| 540 | |
| 541 | |
| 542 | static void destroy() |
| 543 | { |
| 544 | guint i, j, nb; |
| 545 | |
| 546 | LttvLibrary *l, **locked_libraries; |
| 547 | |
| 548 | LttvModule *m; |
| 549 | |
| 550 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Destroy module.c"); |
| 551 | |
| 552 | /* Unload all libraries */ |
| 553 | |
| 554 | nb = libraries->len; |
| 555 | locked_libraries = g_new(LttvLibrary *, nb); |
| 556 | |
| 557 | for(i = 0 ; i < nb ; i++) { |
| 558 | l = (LttvLibrary *)(libraries->pdata[i]); |
| 559 | locked_libraries[i] = l; |
| 560 | library_lock_loaded(l); |
| 561 | for(j = 0 ; j < l->modules->len ; j++) { |
| 562 | m = (LttvModule *)(l->modules->pdata[j]); |
| 563 | while(m->info.require_count > 0) lttv_module_release(m); |
| 564 | } |
| 565 | while(l->info.load_count > 0) lttv_library_unload(l); |
| 566 | } |
| 567 | |
| 568 | for(i = 0 ; i < nb ; i++) { |
| 569 | l = locked_libraries[i]; |
| 570 | library_unlock_loaded(l); |
| 571 | } |
| 572 | g_free(locked_libraries); |
| 573 | |
| 574 | /* The library containing module.c may be locked by our caller */ |
| 575 | |
| 576 | g_assert(libraries->len <= 1); |
| 577 | |
| 578 | initialized = FALSE; |
| 579 | } |
| 580 | |
| 581 | LTTV_MODULE("module", "Modules in libraries", \ |
| 582 | "Load libraries, list, require and initialize contained modules", \ |
| 583 | init, destroy) |
| 584 | |