03d7fdf3 |
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 | |