| 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 | #ifdef HAVE_CONFIG_H |
| 24 | #include <config.h> |
| 25 | #endif |
| 26 | |
| 27 | #include <lttv/module.h> |
| 28 | #include <gmodule.h> |
| 29 | |
| 30 | |
| 31 | struct _LttvLibrary |
| 32 | { |
| 33 | LttvLibraryInfo info; |
| 34 | GPtrArray *modules; |
| 35 | GModule *gm; |
| 36 | guint locked_loaded; |
| 37 | }; |
| 38 | |
| 39 | |
| 40 | struct _LttvModule |
| 41 | { |
| 42 | LttvModuleInfo info; |
| 43 | char **prerequisites_names; |
| 44 | GPtrArray *prerequisites; |
| 45 | }; |
| 46 | |
| 47 | |
| 48 | /* Modules are searched by name. However, a library may be loaded which |
| 49 | provides a module with the same name as an existing one. A stack of |
| 50 | modules is thus maintained for each name. |
| 51 | |
| 52 | Libraries correspond to glib modules. The g_module function is |
| 53 | responsible for loading each library only once. */ |
| 54 | |
| 55 | static GHashTable *modules_by_name = NULL; |
| 56 | |
| 57 | static GPtrArray *libraries = NULL; |
| 58 | |
| 59 | static GHashTable *libraries_by_g_module = NULL; |
| 60 | |
| 61 | static GPtrArray *library_paths = NULL; |
| 62 | |
| 63 | static gboolean initialized = FALSE; |
| 64 | |
| 65 | static gboolean destroyed = TRUE; |
| 66 | |
| 67 | static struct _LttvModuleDescription *builtin_chain = NULL; |
| 68 | |
| 69 | static struct _LttvModuleDescription *module_chain = NULL; |
| 70 | |
| 71 | static struct _LttvModuleDescription **module_next = &module_chain; |
| 72 | |
| 73 | static GQuark lttv_module_error; |
| 74 | |
| 75 | static void init(); |
| 76 | |
| 77 | static void finish_destroy(); |
| 78 | |
| 79 | static void module_release(LttvModule *m); |
| 80 | |
| 81 | |
| 82 | static LttvLibrary *library_add(char *name, char *path, GModule *gm) |
| 83 | { |
| 84 | LttvLibrary *l; |
| 85 | |
| 86 | LttvModule *m; |
| 87 | |
| 88 | struct _LttvModuleDescription *link; |
| 89 | |
| 90 | GPtrArray *modules; |
| 91 | |
| 92 | l = g_new(LttvLibrary, 1); |
| 93 | l->modules = g_ptr_array_new(); |
| 94 | l->gm = gm; |
| 95 | l->locked_loaded = 0; |
| 96 | l->info.name = g_strdup(name); |
| 97 | l->info.path = g_strdup(path); |
| 98 | l->info.load_count = 0; |
| 99 | |
| 100 | g_ptr_array_add(libraries, l); |
| 101 | g_hash_table_insert(libraries_by_g_module, gm, l); |
| 102 | |
| 103 | *module_next = NULL; |
| 104 | for(link = module_chain; link != NULL; link = link->next) { |
| 105 | m = g_new(LttvModule, 1); |
| 106 | g_ptr_array_add(l->modules, m); |
| 107 | |
| 108 | modules = g_hash_table_lookup(modules_by_name, link->name); |
| 109 | if(modules == NULL) { |
| 110 | modules = g_ptr_array_new(); |
| 111 | g_hash_table_insert(modules_by_name, g_strdup(link->name), modules); |
| 112 | } |
| 113 | g_ptr_array_add(modules, m); |
| 114 | |
| 115 | m->prerequisites_names = link->prerequisites; |
| 116 | m->prerequisites = g_ptr_array_new(); |
| 117 | m->info.name = link->name; |
| 118 | m->info.short_description = link->short_description; |
| 119 | m->info.description = link->description; |
| 120 | m->info.init = link->init; |
| 121 | m->info.destroy = link->destroy; |
| 122 | m->info.library = l; |
| 123 | m->info.require_count = 0; |
| 124 | m->info.use_count = 0; |
| 125 | m->info.prerequisites_number = link->prerequisites_number; |
| 126 | } |
| 127 | return l; |
| 128 | } |
| 129 | |
| 130 | |
| 131 | static void library_remove(LttvLibrary *l) |
| 132 | { |
| 133 | LttvModule *m; |
| 134 | |
| 135 | GPtrArray *modules; |
| 136 | GPtrArray **modules_ptr = &modules; /* for strict aliasing */ |
| 137 | guint i; |
| 138 | |
| 139 | char *key; |
| 140 | char **key_ptr = &key; /* for strict aliasing */ |
| 141 | |
| 142 | for(i = 0 ; i < l->modules->len ; i++) { |
| 143 | m = (LttvModule *)(l->modules->pdata[i]); |
| 144 | |
| 145 | g_hash_table_lookup_extended(modules_by_name, m->info.name, |
| 146 | (gpointer *)key_ptr, (gpointer *)modules_ptr); |
| 147 | g_assert(modules != NULL); |
| 148 | g_ptr_array_remove(modules, m); |
| 149 | if(modules->len == 0) { |
| 150 | g_hash_table_remove(modules_by_name, m->info.name); |
| 151 | g_ptr_array_free(modules, TRUE); |
| 152 | g_free(key); |
| 153 | } |
| 154 | |
| 155 | g_ptr_array_free(m->prerequisites, TRUE); |
| 156 | g_free(m); |
| 157 | } |
| 158 | |
| 159 | g_ptr_array_remove(libraries, l); |
| 160 | g_hash_table_remove(libraries_by_g_module, l->gm); |
| 161 | g_ptr_array_free(l->modules, TRUE); |
| 162 | g_free(l->info.name); |
| 163 | g_free(l->info.path); |
| 164 | g_free(l); |
| 165 | } |
| 166 | |
| 167 | |
| 168 | static LttvLibrary *library_load(char *name, GError **error) |
| 169 | { |
| 170 | GModule *gm = NULL; |
| 171 | |
| 172 | int i, nb; |
| 173 | |
| 174 | /* path is always initialized, checked */ |
| 175 | char *path = NULL, *pathname; |
| 176 | |
| 177 | LttvLibrary *l; |
| 178 | |
| 179 | GString *messages = g_string_new(""); |
| 180 | |
| 181 | /* insure that module.c is initialized */ |
| 182 | |
| 183 | init(); |
| 184 | |
| 185 | /* Try to find the library along all the user specified paths */ |
| 186 | |
| 187 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Load library %s", name); |
| 188 | nb = lttv_library_path_number(); |
| 189 | for(i = 0 ; i <= nb ; i++) { |
| 190 | if(i < nb) path = lttv_library_path_get(i); |
| 191 | else path = NULL; |
| 192 | |
| 193 | pathname = g_module_build_path(path ,name); |
| 194 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Try path %s", pathname); |
| 195 | module_chain = NULL; |
| 196 | module_next = &module_chain; |
| 197 | gm = g_module_open(pathname,0); |
| 198 | g_free(pathname); |
| 199 | |
| 200 | if(gm != NULL) break; |
| 201 | |
| 202 | messages = g_string_append(messages, g_module_error()); |
| 203 | messages = g_string_append(messages, "\n"); |
| 204 | g_log(G_LOG_DOMAIN,G_LOG_LEVEL_INFO,"Trial failed, %s", g_module_error()); |
| 205 | } |
| 206 | |
| 207 | /* Module cannot be found */ |
| 208 | |
| 209 | if(gm == NULL) { |
| 210 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Failed to load %s", name); |
| 211 | g_set_error(error, lttv_module_error, LTTV_MODULE_NOT_FOUND, |
| 212 | "Cannot load library %s: %s", name, messages->str); |
| 213 | g_string_free(messages, TRUE); |
| 214 | return NULL; |
| 215 | } |
| 216 | g_string_free(messages, TRUE); |
| 217 | |
| 218 | /* Check if the library was already loaded */ |
| 219 | |
| 220 | l = g_hash_table_lookup(libraries_by_g_module, gm); |
| 221 | |
| 222 | /* This library was not already loaded */ |
| 223 | |
| 224 | if(l == NULL) { |
| 225 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Library %s (%s) loaded", name, |
| 226 | g_module_name(gm)); |
| 227 | l = library_add(name, path, gm); |
| 228 | } |
| 229 | return l; |
| 230 | } |
| 231 | |
| 232 | |
| 233 | LttvLibrary *lttv_library_load(char *name, GError **error) |
| 234 | { |
| 235 | LttvLibrary *l = library_load(name, error); |
| 236 | if(l != NULL) l->info.load_count++; |
| 237 | return l; |
| 238 | } |
| 239 | |
| 240 | /* Returns < 0 if still in use, 0 if freed */ |
| 241 | static gint library_unload(LttvLibrary *l) |
| 242 | { |
| 243 | guint i; |
| 244 | |
| 245 | GModule *gm; |
| 246 | |
| 247 | LttvModule *m; |
| 248 | |
| 249 | if(l->locked_loaded > 0) { |
| 250 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload library %s: locked loaded", |
| 251 | l->info.name); |
| 252 | return 1; |
| 253 | } |
| 254 | |
| 255 | if(l->info.load_count > 0) { |
| 256 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload library %s: load count %d", |
| 257 | l->info.name, l->info.load_count); |
| 258 | return l->info.load_count; |
| 259 | } |
| 260 | |
| 261 | /* Check if all its modules have been released */ |
| 262 | |
| 263 | for(i = 0 ; i < l->modules->len ; i++) { |
| 264 | m = (LttvModule *)(l->modules->pdata[i]); |
| 265 | if(m->info.use_count > 0) { |
| 266 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO,"Unload library %s: module %s used", |
| 267 | l->info.name, m->info.name); |
| 268 | return 1; |
| 269 | } |
| 270 | } |
| 271 | |
| 272 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload library %s: close the GModule", |
| 273 | l->info.name); |
| 274 | gm = l->gm; |
| 275 | library_remove(l); |
| 276 | if(gm != NULL) g_module_close(gm); |
| 277 | |
| 278 | /* insure that module.c will be finalized */ |
| 279 | |
| 280 | finish_destroy(); |
| 281 | return 0; |
| 282 | } |
| 283 | |
| 284 | |
| 285 | gint lttv_library_unload(LttvLibrary *l) |
| 286 | { |
| 287 | /* In the case where we wait for a module to release, the load count is 0 |
| 288 | * and should not be decremented. */ |
| 289 | if(l->info.load_count != 0) { |
| 290 | l->info.load_count--; |
| 291 | return l->info.load_count; |
| 292 | } else { |
| 293 | library_unload(l); |
| 294 | return 0; |
| 295 | } |
| 296 | } |
| 297 | |
| 298 | |
| 299 | static void library_lock_loaded(LttvLibrary *l) |
| 300 | { |
| 301 | l->locked_loaded++; |
| 302 | } |
| 303 | |
| 304 | |
| 305 | static gint library_unlock_loaded(LttvLibrary *l) |
| 306 | { |
| 307 | l->locked_loaded--; |
| 308 | return library_unload(l); |
| 309 | } |
| 310 | |
| 311 | |
| 312 | static LttvModule *module_require(char *name, GError **error) |
| 313 | { |
| 314 | GError *tmp_error = NULL; |
| 315 | |
| 316 | guint i, j; |
| 317 | |
| 318 | LttvModule *m, *required; |
| 319 | |
| 320 | LttvLibrary *l = NULL; |
| 321 | |
| 322 | GPtrArray *modules; |
| 323 | |
| 324 | /* Insure that module.c is initialized */ |
| 325 | |
| 326 | init(); |
| 327 | |
| 328 | /* Check if the module is already loaded */ |
| 329 | |
| 330 | modules = g_hash_table_lookup(modules_by_name, name); |
| 331 | |
| 332 | /* Try to load a library having the module name */ |
| 333 | |
| 334 | if(modules == NULL) { |
| 335 | l = library_load(name, error); |
| 336 | if(l == NULL) return NULL; |
| 337 | else library_lock_loaded(l); |
| 338 | |
| 339 | /* A library was found, does it contain the named module */ |
| 340 | |
| 341 | modules = g_hash_table_lookup(modules_by_name, name); |
| 342 | if(modules == NULL) { |
| 343 | g_set_error(error, lttv_module_error, LTTV_MODULE_NOT_FOUND, |
| 344 | "Module %s not found in library %s", name, l->info.name); |
| 345 | library_unlock_loaded(l); |
| 346 | return NULL; |
| 347 | } |
| 348 | } |
| 349 | m = (LttvModule *)(modules->pdata[modules->len - 1]); |
| 350 | |
| 351 | /* We have the module */ |
| 352 | |
| 353 | m->info.use_count++; |
| 354 | |
| 355 | /* First use of the module. Initialize after getting the prerequisites */ |
| 356 | |
| 357 | if(m->info.use_count == 1) { |
| 358 | for(i = 0 ; i < m->info.prerequisites_number ; i++) { |
| 359 | required = module_require(m->prerequisites_names[i], &tmp_error); |
| 360 | |
| 361 | /* A prerequisite could not be found, undo everything and fail */ |
| 362 | |
| 363 | if(required == NULL) { |
| 364 | for(j = 0 ; j < m->prerequisites->len ; j++) { |
| 365 | module_release((LttvModule *)(m->prerequisites->pdata[j])); |
| 366 | } |
| 367 | g_ptr_array_set_size(m->prerequisites, 0); |
| 368 | if(l != NULL) library_unlock_loaded(l); |
| 369 | g_set_error(error, lttv_module_error, LTTV_MODULE_NOT_FOUND, |
| 370 | "Cannot find prerequisite for module %s: %s", name, |
| 371 | tmp_error->message); |
| 372 | g_clear_error(&tmp_error); |
| 373 | return NULL; |
| 374 | } |
| 375 | g_ptr_array_add(m->prerequisites, required); |
| 376 | } |
| 377 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Module %s: init()", m->info.name); |
| 378 | m->info.init(); |
| 379 | } |
| 380 | |
| 381 | /* Decrement the load count of the library. It will not really be |
| 382 | unloaded since it contains a currently used module. */ |
| 383 | |
| 384 | if(l != NULL) library_unlock_loaded(l); |
| 385 | |
| 386 | return(m); |
| 387 | } |
| 388 | |
| 389 | |
| 390 | /* The require_count for a module is the number of explicit calls to |
| 391 | lttv_module_require, while the use_count also counts the number of times |
| 392 | a module is needed as a prerequisite. */ |
| 393 | |
| 394 | LttvModule *lttv_module_require(char *name, GError **error) |
| 395 | { |
| 396 | LttvModule *m = module_require(name, error); |
| 397 | if(m != NULL) m->info.require_count++; |
| 398 | return(m); |
| 399 | } |
| 400 | |
| 401 | |
| 402 | static void module_release(LttvModule *m) |
| 403 | { |
| 404 | guint i; |
| 405 | |
| 406 | library_lock_loaded(m->info.library); |
| 407 | |
| 408 | m->info.use_count--; |
| 409 | if(m->info.use_count == 0) { |
| 410 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Module %s: destroy()",m->info.name); |
| 411 | m->info.destroy(); |
| 412 | for(i = 0 ; i < m->prerequisites->len ; i++) { |
| 413 | module_release((LttvModule *)(m->prerequisites->pdata[i])); |
| 414 | } |
| 415 | g_ptr_array_set_size(m->prerequisites, 0); |
| 416 | } |
| 417 | library_unlock_loaded(m->info.library); |
| 418 | } |
| 419 | |
| 420 | |
| 421 | void lttv_module_release(LttvModule *m) |
| 422 | { |
| 423 | m->info.require_count--; |
| 424 | module_release(m); |
| 425 | } |
| 426 | |
| 427 | |
| 428 | void lttv_module_info(LttvModule *m, LttvModuleInfo *info) |
| 429 | { |
| 430 | *info = m->info; |
| 431 | } |
| 432 | |
| 433 | |
| 434 | unsigned lttv_module_prerequisite_number(LttvModule *m) |
| 435 | { |
| 436 | return m->prerequisites->len; |
| 437 | } |
| 438 | |
| 439 | |
| 440 | LttvModule *lttv_module_prerequisite_get(LttvModule *m, unsigned i) |
| 441 | { |
| 442 | return (LttvModule *)(m->prerequisites->pdata[i]); |
| 443 | } |
| 444 | |
| 445 | |
| 446 | void lttv_library_info(LttvLibrary *l, LttvLibraryInfo *info) |
| 447 | { |
| 448 | *info = l->info; |
| 449 | } |
| 450 | |
| 451 | |
| 452 | unsigned lttv_library_module_number(LttvLibrary *l) |
| 453 | { |
| 454 | return l->modules->len; |
| 455 | } |
| 456 | |
| 457 | |
| 458 | LttvModule *lttv_library_module_get(LttvLibrary *l, unsigned i) |
| 459 | { |
| 460 | return (LttvModule *)(l->modules->pdata[i]); |
| 461 | } |
| 462 | |
| 463 | |
| 464 | unsigned lttv_library_number() |
| 465 | { |
| 466 | return libraries->len; |
| 467 | } |
| 468 | |
| 469 | |
| 470 | LttvLibrary *lttv_library_get(unsigned i) |
| 471 | { |
| 472 | return (LttvLibrary *)(libraries->pdata[i]); |
| 473 | } |
| 474 | |
| 475 | |
| 476 | void lttv_library_path_add(const char *name) |
| 477 | { |
| 478 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Add library path %s", name); |
| 479 | g_ptr_array_add(library_paths,(char*)g_strdup(name)); |
| 480 | } |
| 481 | |
| 482 | |
| 483 | void lttv_library_path_remove(const char *name) |
| 484 | { |
| 485 | guint i; |
| 486 | |
| 487 | for(i = 0 ; i < library_paths->len ; i++) { |
| 488 | if(g_str_equal(name, library_paths->pdata[i])) { |
| 489 | g_free(library_paths->pdata[i]); |
| 490 | g_ptr_array_remove_index(library_paths,i); |
| 491 | return; |
| 492 | } |
| 493 | } |
| 494 | } |
| 495 | |
| 496 | |
| 497 | unsigned lttv_library_path_number() |
| 498 | { |
| 499 | return library_paths->len; |
| 500 | } |
| 501 | |
| 502 | |
| 503 | char *lttv_library_path_get(unsigned i) |
| 504 | { |
| 505 | return (char *)(library_paths->pdata[library_paths->len - i - 1]); |
| 506 | } |
| 507 | |
| 508 | |
| 509 | void lttv_module_register(struct _LttvModuleDescription *d) |
| 510 | { |
| 511 | *module_next = d; |
| 512 | module_next = &(d->next); |
| 513 | } |
| 514 | |
| 515 | |
| 516 | static void init() |
| 517 | { |
| 518 | if(initialized) return; |
| 519 | g_assert(destroyed); |
| 520 | |
| 521 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Init module.c"); |
| 522 | |
| 523 | initialized = TRUE; |
| 524 | destroyed = FALSE; |
| 525 | lttv_module_error = g_quark_from_string("LTTV_MODULE_ERROR"); |
| 526 | modules_by_name = g_hash_table_new(g_str_hash, g_str_equal); |
| 527 | libraries = g_ptr_array_new(); |
| 528 | libraries_by_g_module = g_hash_table_new(g_direct_hash, g_direct_equal); |
| 529 | library_paths = g_ptr_array_new(); |
| 530 | |
| 531 | if(builtin_chain == NULL) builtin_chain = module_chain; |
| 532 | module_chain = builtin_chain; |
| 533 | library_add("builtin", NULL, NULL); |
| 534 | } |
| 535 | |
| 536 | |
| 537 | static void finish_destroy() |
| 538 | { |
| 539 | guint i; |
| 540 | |
| 541 | if(initialized) return; |
| 542 | g_assert(!destroyed); |
| 543 | |
| 544 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Finish destroy module.c"); |
| 545 | g_hash_table_destroy(modules_by_name); |
| 546 | g_ptr_array_free(libraries, TRUE); |
| 547 | g_hash_table_destroy(libraries_by_g_module); |
| 548 | for(i = 0 ; i < library_paths->len ; i++) { |
| 549 | g_free(library_paths->pdata[i]); |
| 550 | } |
| 551 | g_ptr_array_free(library_paths, TRUE); |
| 552 | destroyed = TRUE; |
| 553 | } |
| 554 | |
| 555 | |
| 556 | static void destroy() |
| 557 | { |
| 558 | guint i, j, nb; |
| 559 | |
| 560 | LttvLibrary *l, **locked_libraries; |
| 561 | |
| 562 | LttvModule *m; |
| 563 | |
| 564 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Destroy module.c"); |
| 565 | |
| 566 | /* Unload all libraries */ |
| 567 | |
| 568 | nb = libraries->len; |
| 569 | locked_libraries = g_new(LttvLibrary *, nb); |
| 570 | |
| 571 | for(i = 0 ; i < nb ; i++) { |
| 572 | //g_assert(nb == libraries->len); |
| 573 | l = (LttvLibrary *)(libraries->pdata[i]); |
| 574 | locked_libraries[i] = l; |
| 575 | library_lock_loaded(l); |
| 576 | for(j = 0 ; j < l->modules->len ; j++) { |
| 577 | m = (LttvModule *)(l->modules->pdata[j]); |
| 578 | while(m->info.require_count > 0) lttv_module_release(m); |
| 579 | } |
| 580 | if(library_unlock_loaded(l) > 0) |
| 581 | while(lttv_library_unload(l) > 0); |
| 582 | |
| 583 | /* If the number of librairies loaded have changed, restart from the |
| 584 | * beginning */ |
| 585 | if(nb != libraries->len) { |
| 586 | i = 0; |
| 587 | nb = libraries->len; |
| 588 | } |
| 589 | |
| 590 | } |
| 591 | |
| 592 | for(i = 0 ; i < nb ; i++) { |
| 593 | l = locked_libraries[i]; |
| 594 | library_unlock_loaded(l); |
| 595 | } |
| 596 | g_free(locked_libraries); |
| 597 | |
| 598 | /* The library containing module.c may be locked by our caller */ |
| 599 | |
| 600 | g_assert(libraries->len <= 1); |
| 601 | |
| 602 | initialized = FALSE; |
| 603 | } |
| 604 | |
| 605 | LTTV_MODULE("module", "Modules in libraries", \ |
| 606 | "Load libraries, list, require and initialize contained modules", \ |
| 607 | init, destroy) |
| 608 | |