xref: /freebsd/sys/kern/kern_module.c (revision 3642298923e528d795e3a30ec165d2b469e28b40)
1 /*-
2  * Copyright (c) 1997 Doug Rabson
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include "opt_compat.h"
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/kernel.h>
34 #include <sys/systm.h>
35 #include <sys/eventhandler.h>
36 #include <sys/malloc.h>
37 #include <sys/sysproto.h>
38 #include <sys/sysent.h>
39 #include <sys/proc.h>
40 #include <sys/lock.h>
41 #include <sys/mutex.h>
42 #include <sys/reboot.h>
43 #include <sys/sx.h>
44 #include <sys/module.h>
45 #include <sys/linker.h>
46 
47 static MALLOC_DEFINE(M_MODULE, "module", "module data structures");
48 
49 typedef TAILQ_HEAD(, module) modulelist_t;
50 struct module {
51 	TAILQ_ENTRY(module)	link;	/* chain together all modules */
52 	TAILQ_ENTRY(module)	flink;	/* all modules in a file */
53 	struct linker_file	*file;	/* file which contains this module */
54 	int			refs;	/* reference count */
55 	int 			id;	/* unique id number */
56 	char 			*name;	/* module name */
57 	modeventhand_t 		handler;	/* event handler */
58 	void 			*arg;	/* argument for handler */
59 	modspecific_t 		data;	/* module specific data */
60 };
61 
62 #define MOD_EVENT(mod, type)	(mod)->handler((mod), (type), (mod)->arg)
63 
64 static modulelist_t modules;
65 struct sx modules_sx;
66 static int nextid = 1;
67 static void module_shutdown(void *, int);
68 
69 static int
70 modevent_nop(module_t mod, int what, void *arg)
71 {
72 
73 	switch(what) {
74 	case MOD_LOAD:
75 		return (0);
76 	case MOD_UNLOAD:
77 		return (EBUSY);
78 	default:
79 		return (EOPNOTSUPP);
80 	}
81 }
82 
83 static void
84 module_init(void *arg)
85 {
86 
87 	sx_init(&modules_sx, "module subsystem sx lock");
88 	TAILQ_INIT(&modules);
89 	EVENTHANDLER_REGISTER(shutdown_final, module_shutdown, NULL,
90 	    SHUTDOWN_PRI_DEFAULT);
91 }
92 
93 SYSINIT(module, SI_SUB_KLD, SI_ORDER_FIRST, module_init, 0)
94 
95 static void
96 module_shutdown(void *arg1, int arg2)
97 {
98 	module_t mod;
99 
100 	if (arg2 & RB_NOSYNC)
101 		return;
102 	MOD_SLOCK;
103 	TAILQ_FOREACH(mod, &modules, link)
104 		MOD_EVENT(mod, MOD_SHUTDOWN);
105 	MOD_SUNLOCK;
106 }
107 
108 void
109 module_register_init(const void *arg)
110 {
111 	const moduledata_t *data = (const moduledata_t *)arg;
112 	int error;
113 	module_t mod;
114 
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 	}
131 }
132 
133 int
134 module_register(const moduledata_t *data, linker_file_t container)
135 {
136 	size_t namelen;
137 	module_t newmod;
138 
139 	MOD_SLOCK;
140 	newmod = module_lookupbyname(data->name);
141 	if (newmod != NULL) {
142 		MOD_SUNLOCK;
143 		printf("module_register: module %s already exists!\n",
144 		    data->name);
145 		return (EEXIST);
146 	}
147 	MOD_SUNLOCK;
148 	namelen = strlen(data->name) + 1;
149 	newmod = malloc(sizeof(struct module) + namelen, M_MODULE, M_WAITOK);
150 	if (newmod == NULL)
151 		return (ENOMEM);
152 	MOD_XLOCK;
153 	newmod->refs = 1;
154 	newmod->id = nextid++;
155 	newmod->name = (char *)(newmod + 1);
156 	strcpy(newmod->name, data->name);
157 	newmod->handler = data->evhand ? data->evhand : modevent_nop;
158 	newmod->arg = data->priv;
159 	bzero(&newmod->data, sizeof(newmod->data));
160 	TAILQ_INSERT_TAIL(&modules, newmod, link);
161 
162 	if (container)
163 		TAILQ_INSERT_TAIL(&container->modules, newmod, flink);
164 	newmod->file = container;
165 	MOD_XUNLOCK;
166 	return (0);
167 }
168 
169 void
170 module_reference(module_t mod)
171 {
172 
173 	MOD_XLOCK_ASSERT;
174 
175 	MOD_DPF(REFS, ("module_reference: before, refs=%d\n", mod->refs));
176 	mod->refs++;
177 }
178 
179 void
180 module_release(module_t mod)
181 {
182 
183 	MOD_XLOCK_ASSERT;
184 
185 	if (mod->refs <= 0)
186 		panic("module_release: bad reference count");
187 
188 	MOD_DPF(REFS, ("module_release: before, refs=%d\n", mod->refs));
189 
190 	mod->refs--;
191 	if (mod->refs == 0) {
192 		TAILQ_REMOVE(&modules, mod, link);
193 		if (mod->file)
194 			TAILQ_REMOVE(&mod->file->modules, mod, flink);
195 		MOD_XUNLOCK;
196 		free(mod, M_MODULE);
197 		MOD_XLOCK;
198 	}
199 }
200 
201 module_t
202 module_lookupbyname(const char *name)
203 {
204 	module_t mod;
205 	int err;
206 
207 	MOD_LOCK_ASSERT;
208 
209 	TAILQ_FOREACH(mod, &modules, link) {
210 		err = strcmp(mod->name, name);
211 		if (err == 0)
212 			return (mod);
213 	}
214 	return (NULL);
215 }
216 
217 module_t
218 module_lookupbyid(int modid)
219 {
220         module_t mod;
221 
222         MOD_LOCK_ASSERT;
223 
224         TAILQ_FOREACH(mod, &modules, link)
225                 if (mod->id == modid)
226                         return(mod);
227         return (NULL);
228 }
229 
230 int
231 module_unload(module_t mod, int flags)
232 {
233 	int error;
234 
235 	error = MOD_EVENT(mod, MOD_QUIESCE);
236 	if (error == EOPNOTSUPP || error == EINVAL)
237 		error = 0;
238 	if (flags == LINKER_UNLOAD_NORMAL && error != 0)
239 		return (error);
240         return (MOD_EVENT(mod, MOD_UNLOAD));
241 }
242 
243 int
244 module_getid(module_t mod)
245 {
246 
247 	MOD_LOCK_ASSERT;
248 	return (mod->id);
249 }
250 
251 module_t
252 module_getfnext(module_t mod)
253 {
254 
255 	MOD_LOCK_ASSERT;
256 	return (TAILQ_NEXT(mod, flink));
257 }
258 
259 void
260 module_setspecific(module_t mod, modspecific_t *datap)
261 {
262 
263 	MOD_XLOCK_ASSERT;
264 	mod->data = *datap;
265 }
266 
267 /*
268  * Syscalls.
269  */
270 /*
271  * MPSAFE
272  */
273 int
274 modnext(struct thread *td, struct modnext_args *uap)
275 {
276 	module_t mod;
277 	int error = 0;
278 
279 	td->td_retval[0] = -1;
280 
281 	MOD_SLOCK;
282 	if (uap->modid == 0) {
283 		mod = TAILQ_FIRST(&modules);
284 		if (mod)
285 			td->td_retval[0] = mod->id;
286 		else
287 			error = ENOENT;
288 		goto done2;
289 	}
290 	mod = module_lookupbyid(uap->modid);
291 	if (mod == NULL) {
292 		error = ENOENT;
293 		goto done2;
294 	}
295 	if (TAILQ_NEXT(mod, link))
296 		td->td_retval[0] = TAILQ_NEXT(mod, link)->id;
297 	else
298 		td->td_retval[0] = 0;
299 done2:
300 	MOD_SUNLOCK;
301 	return (error);
302 }
303 
304 /*
305  * MPSAFE
306  */
307 int
308 modfnext(struct thread *td, struct modfnext_args *uap)
309 {
310 	module_t mod;
311 	int error;
312 
313 	td->td_retval[0] = -1;
314 
315 	MOD_SLOCK;
316 	mod = module_lookupbyid(uap->modid);
317 	if (mod == NULL) {
318 		error = ENOENT;
319 	} else {
320 		error = 0;
321 		if (TAILQ_NEXT(mod, flink))
322 			td->td_retval[0] = TAILQ_NEXT(mod, flink)->id;
323 		else
324 			td->td_retval[0] = 0;
325 	}
326 	MOD_SUNLOCK;
327 	return (error);
328 }
329 
330 struct module_stat_v1 {
331 	int	version;		/* set to sizeof(struct module_stat) */
332 	char	name[MAXMODNAME];
333 	int	refs;
334 	int	id;
335 };
336 
337 /*
338  * MPSAFE
339  */
340 int
341 modstat(struct thread *td, struct modstat_args *uap)
342 {
343 	module_t mod;
344 	modspecific_t data;
345 	int error = 0;
346 	int id, namelen, refs, version;
347 	struct module_stat *stat;
348 	char *name;
349 
350 	MOD_SLOCK;
351 	mod = module_lookupbyid(uap->modid);
352 	if (mod == NULL) {
353 		MOD_SUNLOCK;
354 		return (ENOENT);
355 	}
356 	id = mod->id;
357 	refs = mod->refs;
358 	name = mod->name;
359 	data = mod->data;
360 	MOD_SUNLOCK;
361 	stat = uap->stat;
362 
363 	/*
364 	 * Check the version of the user's structure.
365 	 */
366 	if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
367 		return (error);
368 	if (version != sizeof(struct module_stat_v1)
369 	    && version != sizeof(struct module_stat))
370 		return (EINVAL);
371 	namelen = strlen(mod->name) + 1;
372 	if (namelen > MAXMODNAME)
373 		namelen = MAXMODNAME;
374 	if ((error = copyout(name, &stat->name[0], namelen)) != 0)
375 		return (error);
376 
377 	if ((error = copyout(&refs, &stat->refs, sizeof(int))) != 0)
378 		return (error);
379 	if ((error = copyout(&id, &stat->id, sizeof(int))) != 0)
380 		return (error);
381 
382 	/*
383 	 * >v1 stat includes module data.
384 	 */
385 	if (version == sizeof(struct module_stat))
386 		if ((error = copyout(&data, &stat->data,
387 		    sizeof(data))) != 0)
388 			return (error);
389 	td->td_retval[0] = 0;
390 	return (error);
391 }
392 
393 /*
394  * MPSAFE
395  */
396 int
397 modfind(struct thread *td, struct modfind_args *uap)
398 {
399 	int error = 0;
400 	char name[MAXMODNAME];
401 	module_t mod;
402 
403 	if ((error = copyinstr(uap->name, name, sizeof name, 0)) != 0)
404 		return (error);
405 
406 	MOD_SLOCK;
407 	mod = module_lookupbyname(name);
408 	if (mod == NULL)
409 		error = ENOENT;
410 	else
411 		td->td_retval[0] = module_getid(mod);
412 	MOD_SUNLOCK;
413 	return (error);
414 }
415 
416 #ifdef COMPAT_IA32
417 #include <sys/mount.h>
418 #include <compat/freebsd32/freebsd32_util.h>
419 #include <compat/freebsd32/freebsd32.h>
420 #include <compat/freebsd32/freebsd32_proto.h>
421 
422 typedef union modspecific32 {
423 	int		intval;
424 	u_int32_t	uintval;
425 	int		longval;
426 	u_int32_t	ulongval;
427 } modspecific32_t;
428 
429 struct module_stat32 {
430 	int		version;
431 	char		name[MAXMODNAME];
432 	int		refs;
433 	int		id;
434 	modspecific32_t	data;
435 };
436 
437 /*
438  * MPSAFE
439  */
440 int
441 freebsd32_modstat(struct thread *td, struct freebsd32_modstat_args *uap)
442 {
443 	module_t mod;
444 	modspecific32_t data32;
445 	int error = 0;
446 	int id, namelen, refs, version;
447 	struct module_stat32 *stat32;
448 	char *name;
449 
450 	MOD_SLOCK;
451 	mod = module_lookupbyid(uap->modid);
452 	if (mod == NULL) {
453 		MOD_SUNLOCK;
454 		return (ENOENT);
455 	}
456 
457 	id = mod->id;
458 	refs = mod->refs;
459 	name = mod->name;
460 	CP(mod->data, data32, intval);
461 	CP(mod->data, data32, uintval);
462 	CP(mod->data, data32, longval);
463 	CP(mod->data, data32, ulongval);
464 	MOD_SUNLOCK;
465 	stat32 = uap->stat;
466 
467 	if ((error = copyin(&stat32->version, &version, sizeof(version))) != 0)
468 		return (error);
469 	if (version != sizeof(struct module_stat_v1)
470 	    && version != sizeof(struct module_stat32))
471 		return (EINVAL);
472 	namelen = strlen(mod->name) + 1;
473 	if (namelen > MAXMODNAME)
474 		namelen = MAXMODNAME;
475 	if ((error = copyout(name, &stat32->name[0], namelen)) != 0)
476 		return (error);
477 
478 	if ((error = copyout(&refs, &stat32->refs, sizeof(int))) != 0)
479 		return (error);
480 	if ((error = copyout(&id, &stat32->id, sizeof(int))) != 0)
481 		return (error);
482 
483 	/*
484 	 * >v1 stat includes module data.
485 	 */
486 	if (version == sizeof(struct module_stat32))
487 		if ((error = copyout(&data32, &stat32->data,
488 		    sizeof(data32))) != 0)
489 			return (error);
490 	td->td_retval[0] = 0;
491 	return (error);
492 }
493 #endif
494