kern_module.c revision 111119 
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 * $FreeBSD: head/sys/kern/kern_module.c 111119 2003-02-19 05:47:46Z imp $
27 */
28
29#include <sys/param.h>
30#include <sys/kernel.h>
31#include <sys/systm.h>
32#include <sys/eventhandler.h>
33#include <sys/malloc.h>
34#include <sys/sysproto.h>
35#include <sys/sysent.h>
36#include <sys/proc.h>
37#include <sys/lock.h>
38#include <sys/mutex.h>
39#include <sys/sx.h>
40#include <sys/module.h>
41#include <sys/linker.h>
42
43static MALLOC_DEFINE(M_MODULE, "module", "module data structures");
44
45typedef TAILQ_HEAD(, module) modulelist_t;
46struct module {
47	TAILQ_ENTRY(module)	link;	/* chain together all modules */
48	TAILQ_ENTRY(module)	flink;	/* all modules in a file */
49	struct linker_file	*file;	/* file which contains this module */
50	int			refs;	/* reference count */
51	int 			id;	/* unique id number */
52	char 			*name;	/* module name */
53	modeventhand_t 		handler;	/* event handler */
54	void 			*arg;	/* argument for handler */
55	modspecific_t 		data;	/* module specific data */
56};
57
58#define MOD_EVENT(mod, type)	(mod)->handler((mod), (type), (mod)->arg)
59
60static modulelist_t modules;
61struct sx modules_sx;
62static int nextid = 1;
63static void module_shutdown(void *, int);
64
65static int
66modevent_nop(module_t mod, int what, void *arg)
67{
68	return (0);
69}
70
71static void
72module_init(void *arg)
73{
74
75	sx_init(&modules_sx, "module subsystem sx lock");
76	TAILQ_INIT(&modules);
77	EVENTHANDLER_REGISTER(shutdown_final, module_shutdown, NULL,
78	    SHUTDOWN_PRI_DEFAULT);
79}
80
81SYSINIT(module, SI_SUB_KLD, SI_ORDER_FIRST, module_init, 0)
82
83static void
84module_shutdown(void *arg1, int arg2)
85{
86	module_t mod;
87
88	MOD_SLOCK;
89	TAILQ_FOREACH(mod, &modules, link)
90		MOD_EVENT(mod, MOD_SHUTDOWN);
91	MOD_SUNLOCK;
92}
93
94void
95module_register_init(const void *arg)
96{
97	const moduledata_t *data = (const moduledata_t *)arg;
98	int error;
99	module_t mod;
100
101	MOD_SLOCK;
102	mod = module_lookupbyname(data->name);
103	if (mod == NULL)
104		panic("module_register_init: module named %s not found\n",
105		    data->name);
106	MOD_SUNLOCK;
107	error = MOD_EVENT(mod, MOD_LOAD);
108	if (error) {
109		MOD_EVENT(mod, MOD_UNLOAD);
110		MOD_XLOCK;
111		module_release(mod);
112		MOD_XUNLOCK;
113		printf("module_register_init: MOD_LOAD (%s, %p, %p) error"
114		    " %d\n", data->name, (void *)data->evhand, data->priv,
115		    error);
116	}
117}
118
119int
120module_register(const moduledata_t *data, linker_file_t container)
121{
122	size_t namelen;
123	module_t newmod;
124
125	MOD_SLOCK;
126	newmod = module_lookupbyname(data->name);
127	if (newmod != NULL) {
128		MOD_SUNLOCK;
129		printf("module_register: module %s already exists!\n",
130		    data->name);
131		return (EEXIST);
132	}
133	MOD_SUNLOCK;
134	namelen = strlen(data->name) + 1;
135	newmod = malloc(sizeof(struct module) + namelen, M_MODULE, M_WAITOK);
136	if (newmod == NULL)
137		return (ENOMEM);
138	MOD_XLOCK;
139	newmod->refs = 1;
140	newmod->id = nextid++;
141	newmod->name = (char *)(newmod + 1);
142	strcpy(newmod->name, data->name);
143	newmod->handler = data->evhand ? data->evhand : modevent_nop;
144	newmod->arg = data->priv;
145	bzero(&newmod->data, sizeof(newmod->data));
146	TAILQ_INSERT_TAIL(&modules, newmod, link);
147
148	if (container)
149		TAILQ_INSERT_TAIL(&container->modules, newmod, flink);
150	newmod->file = container;
151	MOD_XUNLOCK;
152	return (0);
153}
154
155void
156module_reference(module_t mod)
157{
158
159	MOD_XLOCK_ASSERT;
160
161	MOD_DPF(REFS, ("module_reference: before, refs=%d\n", mod->refs));
162	mod->refs++;
163}
164
165void
166module_release(module_t mod)
167{
168
169	MOD_XLOCK_ASSERT;
170
171	if (mod->refs <= 0)
172		panic("module_release: bad reference count");
173
174	MOD_DPF(REFS, ("module_release: before, refs=%d\n", mod->refs));
175
176	mod->refs--;
177	if (mod->refs == 0) {
178		TAILQ_REMOVE(&modules, mod, link);
179		if (mod->file)
180			TAILQ_REMOVE(&mod->file->modules, mod, flink);
181		MOD_XUNLOCK;
182		free(mod, M_MODULE);
183		MOD_XLOCK;
184	}
185}
186
187module_t
188module_lookupbyname(const char *name)
189{
190	module_t mod;
191	int err;
192
193	MOD_LOCK_ASSERT;
194
195	TAILQ_FOREACH(mod, &modules, link) {
196		err = strcmp(mod->name, name);
197		if (err == 0)
198			return (mod);
199	}
200	return (NULL);
201}
202
203module_t
204module_lookupbyid(int modid)
205{
206        module_t mod;
207
208        MOD_LOCK_ASSERT;
209
210        TAILQ_FOREACH(mod, &modules, link)
211                if (mod->id == modid)
212                        return(mod);
213        return (NULL);
214}
215
216int
217module_unload(module_t mod)
218{
219
220        return (MOD_EVENT(mod, MOD_UNLOAD));
221}
222
223int
224module_getid(module_t mod)
225{
226
227	MOD_LOCK_ASSERT;
228	return (mod->id);
229}
230
231module_t
232module_getfnext(module_t mod)
233{
234
235	MOD_LOCK_ASSERT;
236	return (TAILQ_NEXT(mod, flink));
237}
238
239void
240module_setspecific(module_t mod, modspecific_t *datap)
241{
242
243	MOD_XLOCK_ASSERT;
244	mod->data = *datap;
245}
246
247/*
248 * Syscalls.
249 */
250/*
251 * MPSAFE
252 */
253int
254modnext(struct thread *td, struct modnext_args *uap)
255{
256	module_t mod;
257	int error = 0;
258
259	td->td_retval[0] = -1;
260
261	MOD_SLOCK;
262	if (uap->modid == 0) {
263		mod = TAILQ_FIRST(&modules);
264		if (mod)
265			td->td_retval[0] = mod->id;
266		else
267			error = ENOENT;
268		goto done2;
269	}
270	mod = module_lookupbyid(uap->modid);
271	if (mod == NULL) {
272		error = ENOENT;
273		goto done2;
274	}
275	if (TAILQ_NEXT(mod, link))
276		td->td_retval[0] = TAILQ_NEXT(mod, link)->id;
277	else
278		td->td_retval[0] = 0;
279done2:
280	MOD_SUNLOCK;
281	return (error);
282}
283
284/*
285 * MPSAFE
286 */
287int
288modfnext(struct thread *td, struct modfnext_args *uap)
289{
290	module_t mod;
291	int error;
292
293	td->td_retval[0] = -1;
294
295	MOD_SLOCK;
296	mod = module_lookupbyid(uap->modid);
297	if (mod == NULL) {
298		error = ENOENT;
299	} else {
300		error = 0;
301		if (TAILQ_NEXT(mod, flink))
302			td->td_retval[0] = TAILQ_NEXT(mod, flink)->id;
303		else
304			td->td_retval[0] = 0;
305	}
306	MOD_SUNLOCK;
307	return (error);
308}
309
310struct module_stat_v1 {
311	int	version;		/* set to sizeof(struct module_stat) */
312	char	name[MAXMODNAME];
313	int	refs;
314	int	id;
315};
316
317/*
318 * MPSAFE
319 */
320int
321modstat(struct thread *td, struct modstat_args *uap)
322{
323	module_t mod;
324	modspecific_t data;
325	int error = 0;
326	int id, namelen, refs, version;
327	struct module_stat *stat;
328	char *name;
329
330	MOD_SLOCK;
331	mod = module_lookupbyid(uap->modid);
332	if (mod == NULL) {
333		MOD_SUNLOCK;
334		return (ENOENT);
335	}
336	id = mod->id;
337	refs = mod->refs;
338	name = mod->name;
339	data = mod->data;
340	MOD_SUNLOCK;
341	stat = uap->stat;
342
343	/*
344	 * Check the version of the user's structure.
345	 */
346	if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
347		return (error);
348	if (version != sizeof(struct module_stat_v1)
349	    && version != sizeof(struct module_stat))
350		return (EINVAL);
351	namelen = strlen(mod->name) + 1;
352	if (namelen > MAXMODNAME)
353		namelen = MAXMODNAME;
354	if ((error = copyout(name, &stat->name[0], namelen)) != 0)
355		return (error);
356
357	if ((error = copyout(&refs, &stat->refs, sizeof(int))) != 0)
358		return (error);
359	if ((error = copyout(&id, &stat->id, sizeof(int))) != 0)
360		return (error);
361
362	/*
363	 * >v1 stat includes module data.
364	 */
365	if (version == sizeof(struct module_stat))
366		if ((error = copyout(&data, &stat->data,
367		    sizeof(data))) != 0)
368			return (error);
369	td->td_retval[0] = 0;
370	return (error);
371}
372
373/*
374 * MPSAFE
375 */
376int
377modfind(struct thread *td, struct modfind_args *uap)
378{
379	int error = 0;
380	char name[MAXMODNAME];
381	module_t mod;
382
383	if ((error = copyinstr(uap->name, name, sizeof name, 0)) != 0)
384		return (error);
385
386	MOD_SLOCK;
387	mod = module_lookupbyname(name);
388	if (mod == NULL)
389		error = ENOENT;
390	else
391		td->td_retval[0] = module_getid(mod);
392	MOD_SUNLOCK;
393	return (error);
394}
395