kern_module.c revision 159634 
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: head/sys/kern/kern_module.c 159634 2006-06-15 08:53:09Z maxim $");
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
47static MALLOC_DEFINE(M_MODULE, "module", "module data structures");
48
49typedef TAILQ_HEAD(, module) modulelist_t;
50struct 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
64static modulelist_t modules;
65struct sx modules_sx;
66static int nextid = 1;
67static void module_shutdown(void *, int);
68
69static int
70modevent_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
83static void
84module_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
93SYSINIT(module, SI_SUB_KLD, SI_ORDER_FIRST, module_init, 0)
94
95static void
96module_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
108void
109module_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
133int
134module_register(const moduledata_t *data, linker_file_t container)
135{
136	size_t namelen;
137	module_t newmod;
138
139	MOD_XLOCK;
140	newmod = module_lookupbyname(data->name);
141	if (newmod != NULL) {
142		MOD_XUNLOCK;
143		printf("module_register: module %s already exists!\n",
144		    data->name);
145		return (EEXIST);
146	}
147	namelen = strlen(data->name) + 1;
148	newmod = malloc(sizeof(struct module) + namelen, M_MODULE, M_WAITOK);
149	if (newmod == NULL) {
150		MOD_XUNLOCK;
151		return (ENOMEM);
152	}
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
169void
170module_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
179void
180module_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
201module_t
202module_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
217module_t
218module_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
230int
231module_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
243int
244module_getid(module_t mod)
245{
246
247	MOD_LOCK_ASSERT;
248	return (mod->id);
249}
250
251module_t
252module_getfnext(module_t mod)
253{
254
255	MOD_LOCK_ASSERT;
256	return (TAILQ_NEXT(mod, flink));
257}
258
259void
260module_setspecific(module_t mod, modspecific_t *datap)
261{
262
263	MOD_XLOCK_ASSERT;
264	mod->data = *datap;
265}
266
267linker_file_t
268module_file(module_t mod)
269{
270
271	return (mod->file);
272}
273
274/*
275 * Syscalls.
276 */
277/*
278 * MPSAFE
279 */
280int
281modnext(struct thread *td, struct modnext_args *uap)
282{
283	module_t mod;
284	int error = 0;
285
286	td->td_retval[0] = -1;
287
288	MOD_SLOCK;
289	if (uap->modid == 0) {
290		mod = TAILQ_FIRST(&modules);
291		if (mod)
292			td->td_retval[0] = mod->id;
293		else
294			error = ENOENT;
295		goto done2;
296	}
297	mod = module_lookupbyid(uap->modid);
298	if (mod == NULL) {
299		error = ENOENT;
300		goto done2;
301	}
302	if (TAILQ_NEXT(mod, link))
303		td->td_retval[0] = TAILQ_NEXT(mod, link)->id;
304	else
305		td->td_retval[0] = 0;
306done2:
307	MOD_SUNLOCK;
308	return (error);
309}
310
311/*
312 * MPSAFE
313 */
314int
315modfnext(struct thread *td, struct modfnext_args *uap)
316{
317	module_t mod;
318	int error;
319
320	td->td_retval[0] = -1;
321
322	MOD_SLOCK;
323	mod = module_lookupbyid(uap->modid);
324	if (mod == NULL) {
325		error = ENOENT;
326	} else {
327		error = 0;
328		if (TAILQ_NEXT(mod, flink))
329			td->td_retval[0] = TAILQ_NEXT(mod, flink)->id;
330		else
331			td->td_retval[0] = 0;
332	}
333	MOD_SUNLOCK;
334	return (error);
335}
336
337struct module_stat_v1 {
338	int	version;		/* set to sizeof(struct module_stat) */
339	char	name[MAXMODNAME];
340	int	refs;
341	int	id;
342};
343
344/*
345 * MPSAFE
346 */
347int
348modstat(struct thread *td, struct modstat_args *uap)
349{
350	module_t mod;
351	modspecific_t data;
352	int error = 0;
353	int id, namelen, refs, version;
354	struct module_stat *stat;
355	char *name;
356
357	MOD_SLOCK;
358	mod = module_lookupbyid(uap->modid);
359	if (mod == NULL) {
360		MOD_SUNLOCK;
361		return (ENOENT);
362	}
363	id = mod->id;
364	refs = mod->refs;
365	name = mod->name;
366	data = mod->data;
367	MOD_SUNLOCK;
368	stat = uap->stat;
369
370	/*
371	 * Check the version of the user's structure.
372	 */
373	if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
374		return (error);
375	if (version != sizeof(struct module_stat_v1)
376	    && version != sizeof(struct module_stat))
377		return (EINVAL);
378	namelen = strlen(mod->name) + 1;
379	if (namelen > MAXMODNAME)
380		namelen = MAXMODNAME;
381	if ((error = copyout(name, &stat->name[0], namelen)) != 0)
382		return (error);
383
384	if ((error = copyout(&refs, &stat->refs, sizeof(int))) != 0)
385		return (error);
386	if ((error = copyout(&id, &stat->id, sizeof(int))) != 0)
387		return (error);
388
389	/*
390	 * >v1 stat includes module data.
391	 */
392	if (version == sizeof(struct module_stat))
393		if ((error = copyout(&data, &stat->data,
394		    sizeof(data))) != 0)
395			return (error);
396	td->td_retval[0] = 0;
397	return (error);
398}
399
400/*
401 * MPSAFE
402 */
403int
404modfind(struct thread *td, struct modfind_args *uap)
405{
406	int error = 0;
407	char name[MAXMODNAME];
408	module_t mod;
409
410	if ((error = copyinstr(uap->name, name, sizeof name, 0)) != 0)
411		return (error);
412
413	MOD_SLOCK;
414	mod = module_lookupbyname(name);
415	if (mod == NULL)
416		error = ENOENT;
417	else
418		td->td_retval[0] = module_getid(mod);
419	MOD_SUNLOCK;
420	return (error);
421}
422
423#ifdef COMPAT_IA32
424#include <sys/mount.h>
425#include <compat/freebsd32/freebsd32_util.h>
426#include <compat/freebsd32/freebsd32.h>
427#include <compat/freebsd32/freebsd32_proto.h>
428
429typedef union modspecific32 {
430	int		intval;
431	u_int32_t	uintval;
432	int		longval;
433	u_int32_t	ulongval;
434} modspecific32_t;
435
436struct module_stat32 {
437	int		version;
438	char		name[MAXMODNAME];
439	int		refs;
440	int		id;
441	modspecific32_t	data;
442};
443
444/*
445 * MPSAFE
446 */
447int
448freebsd32_modstat(struct thread *td, struct freebsd32_modstat_args *uap)
449{
450	module_t mod;
451	modspecific32_t data32;
452	int error = 0;
453	int id, namelen, refs, version;
454	struct module_stat32 *stat32;
455	char *name;
456
457	MOD_SLOCK;
458	mod = module_lookupbyid(uap->modid);
459	if (mod == NULL) {
460		MOD_SUNLOCK;
461		return (ENOENT);
462	}
463
464	id = mod->id;
465	refs = mod->refs;
466	name = mod->name;
467	CP(mod->data, data32, intval);
468	CP(mod->data, data32, uintval);
469	CP(mod->data, data32, longval);
470	CP(mod->data, data32, ulongval);
471	MOD_SUNLOCK;
472	stat32 = uap->stat;
473
474	if ((error = copyin(&stat32->version, &version, sizeof(version))) != 0)
475		return (error);
476	if (version != sizeof(struct module_stat_v1)
477	    && version != sizeof(struct module_stat32))
478		return (EINVAL);
479	namelen = strlen(mod->name) + 1;
480	if (namelen > MAXMODNAME)
481		namelen = MAXMODNAME;
482	if ((error = copyout(name, &stat32->name[0], namelen)) != 0)
483		return (error);
484
485	if ((error = copyout(&refs, &stat32->refs, sizeof(int))) != 0)
486		return (error);
487	if ((error = copyout(&id, &stat32->id, sizeof(int))) != 0)
488		return (error);
489
490	/*
491	 * >v1 stat includes module data.
492	 */
493	if (version == sizeof(struct module_stat32))
494		if ((error = copyout(&data32, &stat32->data,
495		    sizeof(data32))) != 0)
496			return (error);
497	td->td_retval[0] = 0;
498	return (error);
499}
500#endif
501