kern_module.c revision 90980 
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 90980 2002-02-20 16:05:30Z arr $
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(
106	"module_register_init: MOD_LOAD (%s, %lx, %p) error %d\n",
107		data->name, (u_long)(uintfptr_t)data->evhand, data->priv,
108		error);
109	}
110}
111
112int
113module_register(const moduledata_t *data, linker_file_t container)
114{
115	size_t namelen;
116	module_t newmod;
117
118	newmod = module_lookupbyname(data->name);
119	if (newmod != NULL) {
120		printf("module_register: module %s already exists!\n",
121		    data->name);
122		return (EEXIST);
123	}
124	namelen = strlen(data->name) + 1;
125	newmod = malloc(sizeof(struct module) + namelen, M_MODULE, M_WAITOK);
126	if (newmod == NULL)
127		return (ENOMEM);
128	newmod->refs = 1;
129	newmod->id = nextid++;
130	newmod->name = (char *)(newmod + 1);
131	strcpy(newmod->name, data->name);
132	newmod->handler = data->evhand ? data->evhand : modevent_nop;
133	newmod->arg = data->priv;
134	bzero(&newmod->data, sizeof(newmod->data));
135	TAILQ_INSERT_TAIL(&modules, newmod, link);
136
137	if (container)
138		TAILQ_INSERT_TAIL(&container->modules, newmod, flink);
139	newmod->file = container;
140	return (0);
141}
142
143void
144module_reference(module_t mod)
145{
146
147	MOD_DPF(REFS, ("module_reference: before, refs=%d\n", mod->refs));
148	mod->refs++;
149}
150
151void
152module_release(module_t mod)
153{
154
155	if (mod->refs <= 0)
156		panic("module_release: bad reference count");
157
158	MOD_DPF(REFS, ("module_release: before, refs=%d\n", mod->refs));
159
160	mod->refs--;
161	if (mod->refs == 0) {
162		TAILQ_REMOVE(&modules, mod, link);
163		if (mod->file)
164			TAILQ_REMOVE(&mod->file->modules, mod, flink);
165		free(mod, M_MODULE);
166	}
167}
168
169module_t
170module_lookupbyname(const char *name)
171{
172	module_t mod;
173	int err;
174
175	TAILQ_FOREACH(mod, &modules, link) {
176		err = strcmp(mod->name, name);
177		if (err == 0)
178			return (mod);
179	}
180	return (NULL);
181}
182
183module_t
184module_lookupbyid(int modid)
185{
186	module_t mod;
187
188	TAILQ_FOREACH(mod, &modules, link) {
189		if (mod->id == modid)
190			return (mod);
191	}
192	return (NULL);
193}
194
195int
196module_unload(module_t mod)
197{
198
199	return (MOD_EVENT(mod, MOD_UNLOAD));
200}
201
202int
203module_getid(module_t mod)
204{
205
206	return (mod->id);
207}
208
209module_t
210module_getfnext(module_t mod)
211{
212
213	return (TAILQ_NEXT(mod, flink));
214}
215
216void
217module_setspecific(module_t mod, modspecific_t *datap)
218{
219
220	mod->data = *datap;
221}
222
223/*
224 * Syscalls.
225 */
226/*
227 * MPSAFE
228 */
229int
230modnext(struct thread *td, struct modnext_args *uap)
231{
232	module_t mod;
233	int error = 0;
234
235	mtx_lock(&Giant);
236
237	td->td_retval[0] = -1;
238	if (SCARG(uap, modid) == 0) {
239		mod = TAILQ_FIRST(&modules);
240		if (mod)
241			td->td_retval[0] = mod->id;
242		else
243			error = ENOENT;
244		goto done2;
245	}
246	mod = module_lookupbyid(SCARG(uap, modid));
247	if (mod == NULL) {
248		error = ENOENT;
249		goto done2;
250	}
251	if (TAILQ_NEXT(mod, link))
252		td->td_retval[0] = TAILQ_NEXT(mod, link)->id;
253	else
254		td->td_retval[0] = 0;
255done2:
256	mtx_unlock(&Giant);
257	return (error);
258}
259
260/*
261 * MPSAFE
262 */
263int
264modfnext(struct thread *td, struct modfnext_args *uap)
265{
266	module_t mod;
267	int error;
268
269	td->td_retval[0] = -1;
270
271	mtx_lock(&Giant);
272
273	mod = module_lookupbyid(SCARG(uap, modid));
274	if (mod == NULL) {
275		error = ENOENT;
276	} else {
277		error = 0;
278		if (TAILQ_NEXT(mod, flink))
279			td->td_retval[0] = TAILQ_NEXT(mod, flink)->id;
280		else
281			td->td_retval[0] = 0;
282	}
283	mtx_unlock(&Giant);
284	return (error);
285}
286
287struct module_stat_v1 {
288	int version;	/* set to sizeof(struct module_stat) */
289	char name[MAXMODNAME];
290	int refs;
291	int id;
292};
293
294/*
295 * MPSAFE
296 */
297int
298modstat(struct thread *td, struct modstat_args *uap)
299{
300	module_t mod;
301	int error = 0;
302	int namelen;
303	int version;
304	struct module_stat *stat;
305
306	mtx_lock(&Giant);
307
308	mod = module_lookupbyid(SCARG(uap, modid));
309	if (mod == NULL) {
310		error = ENOENT;
311		goto out;
312	}
313	stat = SCARG(uap, stat);
314
315	/*
316	 * Check the version of the user's structure.
317	 */
318	if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
319		goto out;
320	if (version != sizeof(struct module_stat_v1)
321	    && version != sizeof(struct module_stat)) {
322		error = EINVAL;
323		goto out;
324	}
325	namelen = strlen(mod->name) + 1;
326	if (namelen > MAXMODNAME)
327		namelen = MAXMODNAME;
328	if ((error = copyout(mod->name, &stat->name[0], namelen)) != 0)
329		goto out;
330
331	if ((error = copyout(&mod->refs, &stat->refs, sizeof(int))) != 0)
332		goto out;
333	if ((error = copyout(&mod->id, &stat->id, sizeof(int))) != 0)
334		goto out;
335
336	/*
337	 * >v1 stat includes module data.
338	 */
339	if (version == sizeof(struct module_stat)) {
340		if ((error = copyout(&mod->data, &stat->data,
341		    sizeof(mod->data))) != 0)
342			goto out;
343	}
344	td->td_retval[0] = 0;
345out:
346	mtx_unlock(&Giant);
347	return (error);
348}
349
350/*
351 * MPSAFE
352 */
353int
354modfind(struct thread *td, struct modfind_args *uap)
355{
356	int error = 0;
357	char name[MAXMODNAME];
358	module_t mod;
359
360	if ((error = copyinstr(SCARG(uap, name), name, sizeof name, 0)) != 0)
361		goto out;
362
363	mtx_lock(&Giant);
364	mod = module_lookupbyname(name);
365	if (mod == NULL)
366		error = ENOENT;
367	else
368		td->td_retval[0] = mod->id;
369	mtx_unlock(&Giant);
370out:
371	return (error);
372}
373