xref: /freebsd/sys/kern/kern_module.c (revision d0b2dbfa) 
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 1997 Doug Rabson
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 #include <sys/param.h>
31 #include <sys/kernel.h>
32 #include <sys/systm.h>
33 #include <sys/eventhandler.h>
34 #include <sys/malloc.h>
35 #include <sys/sysproto.h>
36 #include <sys/sysent.h>
37 #include <sys/proc.h>
38 #include <sys/lock.h>
39 #include <sys/mutex.h>
40 #include <sys/reboot.h>
41 #include <sys/sx.h>
42 #include <sys/module.h>
43 #include <sys/linker.h>
44 
45 static MALLOC_DEFINE(M_MODULE, "module", "module data structures");
46 
47 struct module {
48 	TAILQ_ENTRY(module)	link;	/* chain together all modules */
49 	TAILQ_ENTRY(module)	flink;	/* all modules in a file */
50 	struct linker_file	*file;	/* file which contains this module */
51 	int			refs;	/* reference count */
52 	int 			id;	/* unique id number */
53 	char 			*name;	/* module name */
54 	modeventhand_t 		handler;	/* event handler */
55 	void 			*arg;	/* argument for handler */
56 	modspecific_t 		data;	/* module specific data */
57 };
58 
59 #define MOD_EVENT(mod, type)	(mod)->handler((mod), (type), (mod)->arg)
60 
61 static TAILQ_HEAD(modulelist, module) modules;
62 struct sx modules_sx;
63 static int nextid = 1;
64 static void module_shutdown(void *, int);
65 
66 static int
67 modevent_nop(module_t mod, int what, void *arg)
68 {
69 
70 	switch(what) {
71 	case MOD_LOAD:
72 		return (0);
73 	case MOD_UNLOAD:
74 		return (EBUSY);
75 	default:
76 		return (EOPNOTSUPP);
77 	}
78 }
79 
80 static void
81 module_init(void *arg)
82 {
83 
84 	sx_init(&modules_sx, "module subsystem sx lock");
85 	TAILQ_INIT(&modules);
86 	EVENTHANDLER_REGISTER(shutdown_final, module_shutdown, NULL,
87 	    SHUTDOWN_PRI_DEFAULT);
88 }
89 
90 SYSINIT(module, SI_SUB_KLD, SI_ORDER_FIRST, module_init, NULL);
91 
92 static void
93 module_shutdown(void *arg1, int arg2)
94 {
95 	module_t mod;
96 
97 	if (arg2 & RB_NOSYNC)
98 		return;
99 	mtx_lock(&Giant);
100 	MOD_SLOCK;
101 	TAILQ_FOREACH_REVERSE(mod, &modules, modulelist, link)
102 		MOD_EVENT(mod, MOD_SHUTDOWN);
103 	MOD_SUNLOCK;
104 	mtx_unlock(&Giant);
105 }
106 
107 void
108 module_register_init(const void *arg)
109 {
110 	const moduledata_t *data = (const moduledata_t *)arg;
111 	int error;
112 	module_t mod;
113 
114 	mtx_lock(&Giant);
115 	MOD_SLOCK;
116 	mod = module_lookupbyname(data->name);
117 	if (mod == NULL)
118 		panic("module_register_init: module named %s not found\n",
119 		    data->name);
120 	MOD_SUNLOCK;
121 	error = MOD_EVENT(mod, MOD_LOAD);
122 	if (error) {
123 		MOD_EVENT(mod, MOD_UNLOAD);
124 		MOD_XLOCK;
125 		module_release(mod);
126 		MOD_XUNLOCK;
127 		printf("module_register_init: MOD_LOAD (%s, %p, %p) error"
128 		    " %d\n", data->name, (void *)data->evhand, data->priv,
129 		    error);
130 	} else {
131 		MOD_XLOCK;
132 		if (mod->file) {
133 			/*
134 			 * Once a module is successfully loaded, move
135 			 * it to the head of the module list for this
136 			 * linker file.  This resorts the list so that
137 			 * when the kernel linker iterates over the
138 			 * modules to unload them, it will unload them
139 			 * in the reverse order they were loaded.
140 			 */
141 			TAILQ_REMOVE(&mod->file->modules, mod, flink);
142 			TAILQ_INSERT_HEAD(&mod->file->modules, mod, flink);
143 		}
144 		MOD_XUNLOCK;
145 	}
146 	mtx_unlock(&Giant);
147 }
148 
149 int
150 module_register(const moduledata_t *data, linker_file_t container)
151 {
152 	size_t namelen;
153 	module_t newmod;
154 
155 	MOD_XLOCK;
156 	newmod = module_lookupbyname(data->name);
157 	if (newmod != NULL) {
158 		MOD_XUNLOCK;
159 		printf("%s: cannot register %s from %s; already loaded from %s\n",
160 		    __func__, data->name, container->filename, newmod->file->filename);
161 		return (EEXIST);
162 	}
163 	namelen = strlen(data->name) + 1;
164 	newmod = malloc(sizeof(struct module) + namelen, M_MODULE, M_WAITOK);
165 	newmod->refs = 1;
166 	newmod->id = nextid++;
167 	newmod->name = (char *)(newmod + 1);
168 	strcpy(newmod->name, data->name);
169 	newmod->handler = data->evhand ? data->evhand : modevent_nop;
170 	newmod->arg = data->priv;
171 	bzero(&newmod->data, sizeof(newmod->data));
172 	TAILQ_INSERT_TAIL(&modules, newmod, link);
173 
174 	if (container)
175 		TAILQ_INSERT_TAIL(&container->modules, newmod, flink);
176 	newmod->file = container;
177 	MOD_XUNLOCK;
178 	return (0);
179 }
180 
181 void
182 module_reference(module_t mod)
183 {
184 
185 	MOD_XLOCK_ASSERT;
186 
187 	MOD_DPF(REFS, ("module_reference: before, refs=%d\n", mod->refs));
188 	mod->refs++;
189 }
190 
191 void
192 module_release(module_t mod)
193 {
194 
195 	MOD_XLOCK_ASSERT;
196 
197 	if (mod->refs <= 0)
198 		panic("module_release: bad reference count");
199 
200 	MOD_DPF(REFS, ("module_release: before, refs=%d\n", mod->refs));
201 
202 	mod->refs--;
203 	if (mod->refs == 0) {
204 		TAILQ_REMOVE(&modules, mod, link);
205 		if (mod->file)
206 			TAILQ_REMOVE(&mod->file->modules, mod, flink);
207 		free(mod, M_MODULE);
208 	}
209 }
210 
211 module_t
212 module_lookupbyname(const char *name)
213 {
214 	module_t mod;
215 	int err;
216 
217 	MOD_LOCK_ASSERT;
218 
219 	TAILQ_FOREACH(mod, &modules, link) {
220 		err = strcmp(mod->name, name);
221 		if (err == 0)
222 			return (mod);
223 	}
224 	return (NULL);
225 }
226 
227 module_t
228 module_lookupbyid(int modid)
229 {
230         module_t mod;
231 
232         MOD_LOCK_ASSERT;
233 
234         TAILQ_FOREACH(mod, &modules, link)
235                 if (mod->id == modid)
236                         return(mod);
237         return (NULL);
238 }
239 
240 int
241 module_quiesce(module_t mod)
242 {
243 	int error;
244 
245 	mtx_lock(&Giant);
246 	error = MOD_EVENT(mod, MOD_QUIESCE);
247 	mtx_unlock(&Giant);
248 	if (error == EOPNOTSUPP || error == EINVAL)
249 		error = 0;
250 	return (error);
251 }
252 
253 int
254 module_unload(module_t mod)
255 {
256 	int error;
257 
258 	mtx_lock(&Giant);
259 	error = MOD_EVENT(mod, MOD_UNLOAD);
260 	mtx_unlock(&Giant);
261 	return (error);
262 }
263 
264 int
265 module_getid(module_t mod)
266 {
267 
268 	MOD_LOCK_ASSERT;
269 	return (mod->id);
270 }
271 
272 module_t
273 module_getfnext(module_t mod)
274 {
275 
276 	MOD_LOCK_ASSERT;
277 	return (TAILQ_NEXT(mod, flink));
278 }
279 
280 const char *
281 module_getname(module_t mod)
282 {
283 
284 	MOD_LOCK_ASSERT;
285 	return (mod->name);
286 }
287 
288 void
289 module_setspecific(module_t mod, modspecific_t *datap)
290 {
291 
292 	MOD_XLOCK_ASSERT;
293 	mod->data = *datap;
294 }
295 
296 linker_file_t
297 module_file(module_t mod)
298 {
299 
300 	return (mod->file);
301 }
302 
303 /*
304  * Syscalls.
305  */
306 int
307 sys_modnext(struct thread *td, struct modnext_args *uap)
308 {
309 	module_t mod;
310 	int error = 0;
311 
312 	td->td_retval[0] = -1;
313 
314 	MOD_SLOCK;
315 	if (uap->modid == 0) {
316 		mod = TAILQ_FIRST(&modules);
317 		if (mod)
318 			td->td_retval[0] = mod->id;
319 		else
320 			error = ENOENT;
321 		goto done2;
322 	}
323 	mod = module_lookupbyid(uap->modid);
324 	if (mod == NULL) {
325 		error = ENOENT;
326 		goto done2;
327 	}
328 	if (TAILQ_NEXT(mod, link))
329 		td->td_retval[0] = TAILQ_NEXT(mod, link)->id;
330 	else
331 		td->td_retval[0] = 0;
332 done2:
333 	MOD_SUNLOCK;
334 	return (error);
335 }
336 
337 int
338 sys_modfnext(struct thread *td, struct modfnext_args *uap)
339 {
340 	module_t mod;
341 	int error;
342 
343 	td->td_retval[0] = -1;
344 
345 	MOD_SLOCK;
346 	mod = module_lookupbyid(uap->modid);
347 	if (mod == NULL) {
348 		error = ENOENT;
349 	} else {
350 		error = 0;
351 		if (TAILQ_NEXT(mod, flink))
352 			td->td_retval[0] = TAILQ_NEXT(mod, flink)->id;
353 		else
354 			td->td_retval[0] = 0;
355 	}
356 	MOD_SUNLOCK;
357 	return (error);
358 }
359 
360 struct module_stat_v1 {
361 	int	version;		/* set to sizeof(struct module_stat) */
362 	char	name[MAXMODNAMEV1V2];
363 	int	refs;
364 	int	id;
365 };
366 
367 struct module_stat_v2 {
368 	int	version;		/* set to sizeof(struct module_stat) */
369 	char	name[MAXMODNAMEV1V2];
370 	int	refs;
371 	int	id;
372 	modspecific_t	data;
373 };
374 
375 int
376 sys_modstat(struct thread *td, struct modstat_args *uap)
377 {
378 	module_t mod;
379 	modspecific_t data;
380 	int error = 0;
381 	int id, namelen, refs, version;
382 	struct module_stat *stat;
383 	struct module_stat_v2 *stat_v2;
384 	char *name;
385 	bool is_v1v2;
386 
387 	MOD_SLOCK;
388 	mod = module_lookupbyid(uap->modid);
389 	if (mod == NULL) {
390 		MOD_SUNLOCK;
391 		return (ENOENT);
392 	}
393 	id = mod->id;
394 	refs = mod->refs;
395 	name = mod->name;
396 	data = mod->data;
397 	MOD_SUNLOCK;
398 	stat = uap->stat;
399 
400 	/*
401 	 * Check the version of the user's structure.
402 	 */
403 	if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
404 		return (error);
405 	is_v1v2 = (version == sizeof(struct module_stat_v1) ||
406 	    version == sizeof(struct module_stat_v2));
407 	if (!is_v1v2 && version != sizeof(struct module_stat))
408 		return (EINVAL);
409 	namelen = strlen(mod->name) + 1;
410 	if (is_v1v2 && namelen > MAXMODNAMEV1V2)
411 		namelen = MAXMODNAMEV1V2;
412 	else if (namelen > MAXMODNAMEV3)
413 		namelen = MAXMODNAMEV3;
414 	if ((error = copyout(name, &stat->name[0], namelen)) != 0)
415 		return (error);
416 
417 	/* Extending MAXMODNAME gives an offset change for v3. */
418 	if (is_v1v2) {
419 		stat_v2 = (struct module_stat_v2 *)stat;
420 		if ((error = copyout(&refs, &stat_v2->refs, sizeof(int))) != 0)
421 			return (error);
422 		if ((error = copyout(&id, &stat_v2->id, sizeof(int))) != 0)
423 			return (error);
424 	} else {
425 		if ((error = copyout(&refs, &stat->refs, sizeof(int))) != 0)
426 			return (error);
427 		if ((error = copyout(&id, &stat->id, sizeof(int))) != 0)
428 			return (error);
429 	}
430 
431 	/*
432 	 * >v1 stat includes module data.
433 	 */
434 	if (version == sizeof(struct module_stat_v2)) {
435 		if ((error = copyout(&data, &stat_v2->data,
436 		    sizeof(data))) != 0)
437 			return (error);
438 	} else if (version == sizeof(struct module_stat)) {
439 		if ((error = copyout(&data, &stat->data,
440 		    sizeof(data))) != 0)
441 			return (error);
442 	}
443 	td->td_retval[0] = 0;
444 	return (error);
445 }
446 
447 int
448 sys_modfind(struct thread *td, struct modfind_args *uap)
449 {
450 	int error = 0;
451 	char name[MAXMODNAMEV3];
452 	module_t mod;
453 
454 	if ((error = copyinstr(uap->name, name, sizeof name, 0)) != 0)
455 		return (error);
456 
457 	MOD_SLOCK;
458 	mod = module_lookupbyname(name);
459 	if (mod == NULL)
460 		error = ENOENT;
461 	else
462 		td->td_retval[0] = module_getid(mod);
463 	MOD_SUNLOCK;
464 	return (error);
465 }
466 
467 MODULE_VERSION(kernel, __FreeBSD_version);
468 
469 #ifdef COMPAT_FREEBSD32
470 #include <sys/mount.h>
471 #include <sys/socket.h>
472 #include <compat/freebsd32/freebsd32_util.h>
473 #include <compat/freebsd32/freebsd32.h>
474 #include <compat/freebsd32/freebsd32_proto.h>
475 
476 typedef union modspecific32 {
477 	int		intval;
478 	uint32_t	uintval;
479 	int		longval;
480 	uint32_t	ulongval;
481 } modspecific32_t;
482 
483 struct module_stat32_v2 {
484 	int		version;
485 	char		name[MAXMODNAMEV1V2];
486 	int		refs;
487 	int		id;
488 	modspecific32_t	data;
489 };
490 
491 struct module_stat32 {
492 	int		version;
493 	char		name[MAXMODNAME];
494 	int		refs;
495 	int		id;
496 	modspecific32_t	data;
497 };
498 
499 int
500 freebsd32_modstat(struct thread *td, struct freebsd32_modstat_args *uap)
501 {
502 	module_t mod;
503 	modspecific32_t data32;
504 	int error = 0;
505 	int id, namelen, refs, version;
506 	struct module_stat32 *stat32;
507 	struct module_stat32_v2 *stat32_v2;
508 	char *name;
509 	bool is_v1v2;
510 
511 	MOD_SLOCK;
512 	mod = module_lookupbyid(uap->modid);
513 	if (mod == NULL) {
514 		MOD_SUNLOCK;
515 		return (ENOENT);
516 	}
517 
518 	id = mod->id;
519 	refs = mod->refs;
520 	name = mod->name;
521 	_Static_assert(sizeof(data32) == sizeof(data32.uintval),
522 	    "bad modspecific32_t size");
523 	CP(mod->data, data32, uintval);
524 	MOD_SUNLOCK;
525 	stat32 = uap->stat;
526 
527 	if ((error = copyin(&stat32->version, &version, sizeof(version))) != 0)
528 		return (error);
529 	is_v1v2 = (version == sizeof(struct module_stat_v1) ||
530 	    version == sizeof(struct module_stat32_v2));
531 	if (!is_v1v2 && version != sizeof(struct module_stat32))
532 		return (EINVAL);
533 	namelen = strlen(mod->name) + 1;
534 	if (is_v1v2 && namelen > MAXMODNAMEV1V2)
535 		namelen = MAXMODNAMEV1V2;
536 	else if (namelen > MAXMODNAMEV3)
537 		namelen = MAXMODNAMEV3;
538 	if ((error = copyout(name, &stat32->name[0], namelen)) != 0)
539 		return (error);
540 
541 	/* Extending MAXMODNAME gives an offset change for v3. */
542 	if (is_v1v2) {
543 		stat32_v2 = (struct module_stat32_v2 *)stat32;
544 		if ((error = copyout(&refs, &stat32_v2->refs, sizeof(int))) != 0)
545 			return (error);
546 		if ((error = copyout(&id, &stat32_v2->id, sizeof(int))) != 0)
547 			return (error);
548 	} else {
549 		if ((error = copyout(&refs, &stat32->refs, sizeof(int))) != 0)
550 			return (error);
551 		if ((error = copyout(&id, &stat32->id, sizeof(int))) != 0)
552 			return (error);
553 	}
554 
555 	/*
556 	 * >v1 stat includes module data.
557 	 */
558 	if (version == sizeof(struct module_stat32_v2)) {
559 		if ((error = copyout(&data32, &stat32_v2->data,
560 		    sizeof(data32))) != 0)
561 			return (error);
562 	} else if (version == sizeof(struct module_stat32)) {
563 		if ((error = copyout(&data32, &stat32->data,
564 		    sizeof(data32))) != 0)
565 			return (error);
566 	}
567 	td->td_retval[0] = 0;
568 	return (error);
569 }
570 #endif
571