kern_module.c revision 91261 
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 91261 2002-02-26 00:55:27Z peter $
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/module.h>
37#include <sys/linker.h>
38#include <sys/proc.h>
39#include <sys/lock.h>
40#include <sys/mutex.h>
41
42static MALLOC_DEFINE(M_MODULE, "module", "module data structures");
43
44typedef TAILQ_HEAD(, module) modulelist_t;
45struct module {
46	TAILQ_ENTRY(module)	link;	/* chain together all modules */
47	TAILQ_ENTRY(module)	flink;	/* all modules in a file */
48	struct linker_file	*file;	/* file which contains this module */
49	int			refs;	/* reference count */
50	int 			id;	/* unique id number */
51	char 			*name;	/* module name */
52	modeventhand_t 		handler;	/* event handler */
53	void 			*arg;	/* argument for handler */
54	modspecific_t 		data;	/* module specific data */
55};
56
57#define MOD_EVENT(mod, type)	(mod)->handler((mod), (type), (mod)->arg)
58
59static modulelist_t modules;
60static int nextid = 1;
61static void module_shutdown(void *, int);
62
63static int
64modevent_nop(module_t mod, int what, void *arg)
65{
66	return (0);
67}
68
69
70static void
71module_init(void *arg)
72{
73
74	TAILQ_INIT(&modules);
75	EVENTHANDLER_REGISTER(shutdown_post_sync, module_shutdown, NULL,
76	    SHUTDOWN_PRI_DEFAULT);
77}
78
79SYSINIT(module, SI_SUB_KLD, SI_ORDER_FIRST, module_init, 0)
80
81static void
82module_shutdown(void *arg1, int arg2)
83{
84	module_t mod;
85
86	TAILQ_FOREACH(mod, &modules, link)
87		MOD_EVENT(mod, MOD_SHUTDOWN);
88}
89
90void
91module_register_init(const void *arg)
92{
93	const moduledata_t *data = (const moduledata_t *)arg;
94	int error;
95	module_t mod;
96
97	mod = module_lookupbyname(data->name);
98	if (mod == NULL)
99		panic("module_register_init: module named %s not found\n",
100		    data->name);
101	error = MOD_EVENT(mod, MOD_LOAD);
102	if (error) {
103		MOD_EVENT(mod, MOD_UNLOAD);
104		module_release(mod);
105		printf("module_register_init: MOD_LOAD (%s, %p, %p) error"
106		    " %d\n", data->name, (void *)data->evhand, data->priv,
107		    error);
108	}
109}
110
111int
112module_register(const moduledata_t *data, linker_file_t container)
113{
114	size_t namelen;
115	module_t newmod;
116
117	newmod = module_lookupbyname(data->name);
118	if (newmod != NULL) {
119		printf("module_register: module %s already exists!\n",
120		    data->name);
121		return (EEXIST);
122	}
123	namelen = strlen(data->name) + 1;
124	newmod = malloc(sizeof(struct module) + namelen, M_MODULE, M_WAITOK);
125	if (newmod == NULL)
126		return (ENOMEM);
127	newmod->refs = 1;
128	newmod->id = nextid++;
129	newmod->name = (char *)(newmod + 1);
130	strcpy(newmod->name, data->name);
131	newmod->handler = data->evhand ? data->evhand : modevent_nop;
132	newmod->arg = data->priv;
133	bzero(&newmod->data, sizeof(newmod->data));
134	TAILQ_INSERT_TAIL(&modules, newmod, link);
135
136	if (container)
137		TAILQ_INSERT_TAIL(&container->modules, newmod, flink);
138	newmod->file = container;
139	return (0);
140}
141
142void
143module_reference(module_t mod)
144{
145
146	MOD_DPF(REFS, ("module_reference: before, refs=%d\n", mod->refs));
147	mod->refs++;
148}
149
150void
151module_release(module_t mod)
152{
153
154	if (mod->refs <= 0)
155		panic("module_release: bad reference count");
156
157	MOD_DPF(REFS, ("module_release: before, refs=%d\n", mod->refs));
158
159	mod->refs--;
160	if (mod->refs == 0) {
161		TAILQ_REMOVE(&modules, mod, link);
162		if (mod->file)
163			TAILQ_REMOVE(&mod->file->modules, mod, flink);
164		free(mod, M_MODULE);
165	}
166}
167
168module_t
169module_lookupbyname(const char *name)
170{
171	module_t mod;
172	int err;
173
174	TAILQ_FOREACH(mod, &modules, link) {
175		err = strcmp(mod->name, name);
176		if (err == 0)
177			return (mod);
178	}
179	return (NULL);
180}
181
182module_t
183module_lookupbyid(int modid)
184{
185	module_t mod;
186
187	TAILQ_FOREACH(mod, &modules, link) {
188		if (mod->id == modid)
189			return (mod);
190	}
191	return (NULL);
192}
193
194int
195module_unload(module_t mod)
196{
197
198	return (MOD_EVENT(mod, MOD_UNLOAD));
199}
200
201int
202module_getid(module_t mod)
203{
204
205	return (mod->id);
206}
207
208module_t
209module_getfnext(module_t mod)
210{
211
212	return (TAILQ_NEXT(mod, flink));
213}
214
215void
216module_setspecific(module_t mod, modspecific_t *datap)
217{
218
219	mod->data = *datap;
220}
221
222/*
223 * Syscalls.
224 */
225/*
226 * MPSAFE
227 */
228int
229modnext(struct thread *td, struct modnext_args *uap)
230{
231	module_t mod;
232	int error = 0;
233
234	mtx_lock(&Giant);
235
236	td->td_retval[0] = -1;
237	if (SCARG(uap, modid) == 0) {
238		mod = TAILQ_FIRST(&modules);
239		if (mod)
240			td->td_retval[0] = mod->id;
241		else
242			error = ENOENT;
243		goto done2;
244	}
245	mod = module_lookupbyid(SCARG(uap, modid));
246	if (mod == NULL) {
247		error = ENOENT;
248		goto done2;
249	}
250	if (TAILQ_NEXT(mod, link))
251		td->td_retval[0] = TAILQ_NEXT(mod, link)->id;
252	else
253		td->td_retval[0] = 0;
254done2:
255	mtx_unlock(&Giant);
256	return (error);
257}
258
259/*
260 * MPSAFE
261 */
262int
263modfnext(struct thread *td, struct modfnext_args *uap)
264{
265	module_t mod;
266	int error;
267
268	td->td_retval[0] = -1;
269
270	mtx_lock(&Giant);
271
272	mod = module_lookupbyid(SCARG(uap, modid));
273	if (mod == NULL) {
274		error = ENOENT;
275	} else {
276		error = 0;
277		if (TAILQ_NEXT(mod, flink))
278			td->td_retval[0] = TAILQ_NEXT(mod, flink)->id;
279		else
280			td->td_retval[0] = 0;
281	}
282	mtx_unlock(&Giant);
283	return (error);
284}
285
286struct module_stat_v1 {
287	int	version;		/* set to sizeof(struct module_stat) */
288	char	name[MAXMODNAME];
289	int	refs;
290	int	id;
291};
292
293/*
294 * MPSAFE
295 */
296int
297modstat(struct thread *td, struct modstat_args *uap)
298{
299	module_t mod;
300	int error = 0;
301	int namelen;
302	int version;
303	struct module_stat *stat;
304
305	mtx_lock(&Giant);
306
307	mod = module_lookupbyid(SCARG(uap, modid));
308	if (mod == NULL) {
309		error = ENOENT;
310		goto out;
311	}
312	stat = SCARG(uap, stat);
313
314	/*
315	 * Check the version of the user's structure.
316	 */
317	if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
318		goto out;
319	if (version != sizeof(struct module_stat_v1)
320	    && version != sizeof(struct module_stat)) {
321		error = EINVAL;
322		goto out;
323	}
324	namelen = strlen(mod->name) + 1;
325	if (namelen > MAXMODNAME)
326		namelen = MAXMODNAME;
327	if ((error = copyout(mod->name, &stat->name[0], namelen)) != 0)
328		goto out;
329
330	if ((error = copyout(&mod->refs, &stat->refs, sizeof(int))) != 0)
331		goto out;
332	if ((error = copyout(&mod->id, &stat->id, sizeof(int))) != 0)
333		goto out;
334
335	/*
336	 * >v1 stat includes module data.
337	 */
338	if (version == sizeof(struct module_stat)) {
339		if ((error = copyout(&mod->data, &stat->data,
340		    sizeof(mod->data))) != 0)
341			goto out;
342	}
343	td->td_retval[0] = 0;
344out:
345	mtx_unlock(&Giant);
346	return (error);
347}
348
349/*
350 * MPSAFE
351 */
352int
353modfind(struct thread *td, struct modfind_args *uap)
354{
355	int error = 0;
356	char name[MAXMODNAME];
357	module_t mod;
358
359	if ((error = copyinstr(SCARG(uap, name), name, sizeof name, 0)) != 0)
360		goto out;
361
362	mtx_lock(&Giant);
363	mod = module_lookupbyname(name);
364	if (mod == NULL)
365		error = ENOENT;
366	else
367		td->td_retval[0] = mod->id;
368	mtx_unlock(&Giant);
369out:
370	return (error);
371}
372