1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1997 Doug Rabson
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
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/reboot.h>
40#include <sys/sx.h>
41#include <sys/module.h>
42#include <sys/linker.h>
43
44static MALLOC_DEFINE(M_MODULE, "module", "module data structures");
45
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 TAILQ_HEAD(modulelist, module) 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
69	switch(what) {
70	case MOD_LOAD:
71		return (0);
72	case MOD_UNLOAD:
73		return (EBUSY);
74	default:
75		return (EOPNOTSUPP);
76	}
77}
78
79static void
80module_init(void *arg)
81{
82
83	sx_init(&modules_sx, "module subsystem sx lock");
84	TAILQ_INIT(&modules);
85	EVENTHANDLER_REGISTER(shutdown_final, module_shutdown, NULL,
86	    SHUTDOWN_PRI_DEFAULT);
87}
88
89SYSINIT(module, SI_SUB_KLD, SI_ORDER_FIRST, module_init, NULL);
90
91static void
92module_shutdown(void *arg1, int arg2)
93{
94	module_t mod;
95
96	if (arg2 & RB_NOSYNC)
97		return;
98	mtx_lock(&Giant);
99	MOD_SLOCK;
100	TAILQ_FOREACH_REVERSE(mod, &modules, modulelist, link)
101		MOD_EVENT(mod, MOD_SHUTDOWN);
102	MOD_SUNLOCK;
103	mtx_unlock(&Giant);
104}
105
106void
107module_register_init(const void *arg)
108{
109	const moduledata_t *data = (const moduledata_t *)arg;
110	int error;
111	module_t mod;
112
113	mtx_lock(&Giant);
114	MOD_SLOCK;
115	mod = module_lookupbyname(data->name);
116	if (mod == NULL)
117		panic("module_register_init: module named %s not found\n",
118		    data->name);
119	MOD_SUNLOCK;
120	error = MOD_EVENT(mod, MOD_LOAD);
121	if (error) {
122		MOD_EVENT(mod, MOD_UNLOAD);
123		MOD_XLOCK;
124		module_release(mod);
125		MOD_XUNLOCK;
126		printf("module_register_init: MOD_LOAD (%s, %p, %p) error"
127		    " %d\n", data->name, (void *)data->evhand, data->priv,
128		    error);
129	} else {
130		MOD_XLOCK;
131		if (mod->file) {
132			/*
133			 * Once a module is successfully loaded, move
134			 * it to the head of the module list for this
135			 * linker file.  This resorts the list so that
136			 * when the kernel linker iterates over the
137			 * modules to unload them, it will unload them
138			 * in the reverse order they were loaded.
139			 */
140			TAILQ_REMOVE(&mod->file->modules, mod, flink);
141			TAILQ_INSERT_HEAD(&mod->file->modules, mod, flink);
142		}
143		MOD_XUNLOCK;
144	}
145	mtx_unlock(&Giant);
146}
147
148int
149module_register(const moduledata_t *data, linker_file_t container)
150{
151	size_t namelen;
152	module_t newmod;
153
154	MOD_XLOCK;
155	newmod = module_lookupbyname(data->name);
156	if (newmod != NULL) {
157		MOD_XUNLOCK;
158		printf("%s: cannot register %s from %s; already loaded from %s\n",
159		    __func__, data->name, container->filename, newmod->file->filename);
160		return (EEXIST);
161	}
162	namelen = strlen(data->name) + 1;
163	newmod = malloc(sizeof(struct module) + namelen, M_MODULE, M_WAITOK);
164	newmod->refs = 1;
165	newmod->id = nextid++;
166	newmod->name = (char *)(newmod + 1);
167	strcpy(newmod->name, data->name);
168	newmod->handler = data->evhand ? data->evhand : modevent_nop;
169	newmod->arg = data->priv;
170	bzero(&newmod->data, sizeof(newmod->data));
171	TAILQ_INSERT_TAIL(&modules, newmod, link);
172
173	if (container)
174		TAILQ_INSERT_TAIL(&container->modules, newmod, flink);
175	newmod->file = container;
176	MOD_XUNLOCK;
177	return (0);
178}
179
180void
181module_reference(module_t mod)
182{
183
184	MOD_XLOCK_ASSERT;
185
186	MOD_DPF(REFS, ("module_reference: before, refs=%d\n", mod->refs));
187	mod->refs++;
188}
189
190void
191module_release(module_t mod)
192{
193
194	MOD_XLOCK_ASSERT;
195
196	if (mod->refs <= 0)
197		panic("module_release: bad reference count");
198
199	MOD_DPF(REFS, ("module_release: before, refs=%d\n", mod->refs));
200
201	mod->refs--;
202	if (mod->refs == 0) {
203		TAILQ_REMOVE(&modules, mod, link);
204		if (mod->file)
205			TAILQ_REMOVE(&mod->file->modules, mod, flink);
206		free(mod, M_MODULE);
207	}
208}
209
210module_t
211module_lookupbyname(const char *name)
212{
213	module_t mod;
214	int err;
215
216	MOD_LOCK_ASSERT;
217
218	TAILQ_FOREACH(mod, &modules, link) {
219		err = strcmp(mod->name, name);
220		if (err == 0)
221			return (mod);
222	}
223	return (NULL);
224}
225
226module_t
227module_lookupbyid(int modid)
228{
229        module_t mod;
230
231        MOD_LOCK_ASSERT;
232
233        TAILQ_FOREACH(mod, &modules, link)
234                if (mod->id == modid)
235                        return(mod);
236        return (NULL);
237}
238
239int
240module_quiesce(module_t mod)
241{
242	int error;
243
244	mtx_lock(&Giant);
245	error = MOD_EVENT(mod, MOD_QUIESCE);
246	mtx_unlock(&Giant);
247	if (error == EOPNOTSUPP || error == EINVAL)
248		error = 0;
249	return (error);
250}
251
252int
253module_unload(module_t mod)
254{
255	int error;
256
257	mtx_lock(&Giant);
258	error = MOD_EVENT(mod, MOD_UNLOAD);
259	mtx_unlock(&Giant);
260	return (error);
261}
262
263int
264module_getid(module_t mod)
265{
266
267	MOD_LOCK_ASSERT;
268	return (mod->id);
269}
270
271module_t
272module_getfnext(module_t mod)
273{
274
275	MOD_LOCK_ASSERT;
276	return (TAILQ_NEXT(mod, flink));
277}
278
279const char *
280module_getname(module_t mod)
281{
282
283	MOD_LOCK_ASSERT;
284	return (mod->name);
285}
286
287void
288module_setspecific(module_t mod, modspecific_t *datap)
289{
290
291	MOD_XLOCK_ASSERT;
292	mod->data = *datap;
293}
294
295linker_file_t
296module_file(module_t mod)
297{
298
299	return (mod->file);
300}
301
302/*
303 * Syscalls.
304 */
305int
306sys_modnext(struct thread *td, struct modnext_args *uap)
307{
308	module_t mod;
309	int error = 0;
310
311	td->td_retval[0] = -1;
312
313	MOD_SLOCK;
314	if (uap->modid == 0) {
315		mod = TAILQ_FIRST(&modules);
316		if (mod)
317			td->td_retval[0] = mod->id;
318		else
319			error = ENOENT;
320		goto done2;
321	}
322	mod = module_lookupbyid(uap->modid);
323	if (mod == NULL) {
324		error = ENOENT;
325		goto done2;
326	}
327	if (TAILQ_NEXT(mod, link))
328		td->td_retval[0] = TAILQ_NEXT(mod, link)->id;
329	else
330		td->td_retval[0] = 0;
331done2:
332	MOD_SUNLOCK;
333	return (error);
334}
335
336int
337sys_modfnext(struct thread *td, struct modfnext_args *uap)
338{
339	module_t mod;
340	int error;
341
342	td->td_retval[0] = -1;
343
344	MOD_SLOCK;
345	mod = module_lookupbyid(uap->modid);
346	if (mod == NULL) {
347		error = ENOENT;
348	} else {
349		error = 0;
350		if (TAILQ_NEXT(mod, flink))
351			td->td_retval[0] = TAILQ_NEXT(mod, flink)->id;
352		else
353			td->td_retval[0] = 0;
354	}
355	MOD_SUNLOCK;
356	return (error);
357}
358
359struct module_stat_v1 {
360	int	version;		/* set to sizeof(struct module_stat) */
361	char	name[MAXMODNAMEV1V2];
362	int	refs;
363	int	id;
364};
365
366struct module_stat_v2 {
367	int	version;		/* set to sizeof(struct module_stat) */
368	char	name[MAXMODNAMEV1V2];
369	int	refs;
370	int	id;
371	modspecific_t	data;
372};
373
374int
375sys_modstat(struct thread *td, struct modstat_args *uap)
376{
377	module_t mod;
378	modspecific_t data;
379	int error = 0;
380	int id, namelen, refs, version;
381	struct module_stat *stat;
382	struct module_stat_v2 *stat_v2;
383	char *name;
384	bool is_v1v2;
385
386	MOD_SLOCK;
387	mod = module_lookupbyid(uap->modid);
388	if (mod == NULL) {
389		MOD_SUNLOCK;
390		return (ENOENT);
391	}
392	id = mod->id;
393	refs = mod->refs;
394	name = mod->name;
395	data = mod->data;
396	MOD_SUNLOCK;
397	stat = uap->stat;
398
399	/*
400	 * Check the version of the user's structure.
401	 */
402	if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
403		return (error);
404	is_v1v2 = (version == sizeof(struct module_stat_v1) ||
405	    version == sizeof(struct module_stat_v2));
406	if (!is_v1v2 && version != sizeof(struct module_stat))
407		return (EINVAL);
408	namelen = strlen(mod->name) + 1;
409	if (is_v1v2 && namelen > MAXMODNAMEV1V2)
410		namelen = MAXMODNAMEV1V2;
411	else if (namelen > MAXMODNAMEV3)
412		namelen = MAXMODNAMEV3;
413	if ((error = copyout(name, &stat->name[0], namelen)) != 0)
414		return (error);
415
416	/* Extending MAXMODNAME gives an offset change for v3. */
417	if (is_v1v2) {
418		stat_v2 = (struct module_stat_v2 *)stat;
419		if ((error = copyout(&refs, &stat_v2->refs, sizeof(int))) != 0)
420			return (error);
421		if ((error = copyout(&id, &stat_v2->id, sizeof(int))) != 0)
422			return (error);
423	} else {
424		if ((error = copyout(&refs, &stat->refs, sizeof(int))) != 0)
425			return (error);
426		if ((error = copyout(&id, &stat->id, sizeof(int))) != 0)
427			return (error);
428	}
429
430	/*
431	 * >v1 stat includes module data.
432	 */
433	if (version == sizeof(struct module_stat_v2)) {
434		if ((error = copyout(&data, &stat_v2->data,
435		    sizeof(data))) != 0)
436			return (error);
437	} else if (version == sizeof(struct module_stat)) {
438		if ((error = copyout(&data, &stat->data,
439		    sizeof(data))) != 0)
440			return (error);
441	}
442	td->td_retval[0] = 0;
443	return (error);
444}
445
446int
447sys_modfind(struct thread *td, struct modfind_args *uap)
448{
449	int error = 0;
450	char name[MAXMODNAMEV3];
451	module_t mod;
452
453	if ((error = copyinstr(uap->name, name, sizeof name, 0)) != 0)
454		return (error);
455
456	MOD_SLOCK;
457	mod = module_lookupbyname(name);
458	if (mod == NULL)
459		error = ENOENT;
460	else
461		td->td_retval[0] = module_getid(mod);
462	MOD_SUNLOCK;
463	return (error);
464}
465
466MODULE_VERSION(kernel, __FreeBSD_version);
467
468#ifdef COMPAT_FREEBSD32
469#include <sys/mount.h>
470#include <sys/socket.h>
471#include <compat/freebsd32/freebsd32_util.h>
472#include <compat/freebsd32/freebsd32.h>
473#include <compat/freebsd32/freebsd32_proto.h>
474
475typedef union modspecific32 {
476	int		intval;
477	uint32_t	uintval;
478	int		longval;
479	uint32_t	ulongval;
480} modspecific32_t;
481
482struct module_stat32_v2 {
483	int		version;
484	char		name[MAXMODNAMEV1V2];
485	int		refs;
486	int		id;
487	modspecific32_t	data;
488};
489
490struct module_stat32 {
491	int		version;
492	char		name[MAXMODNAME];
493	int		refs;
494	int		id;
495	modspecific32_t	data;
496};
497
498int
499freebsd32_modstat(struct thread *td, struct freebsd32_modstat_args *uap)
500{
501	module_t mod;
502	modspecific32_t data32;
503	int error = 0;
504	int id, namelen, refs, version;
505	struct module_stat32 *stat32;
506	struct module_stat32_v2 *stat32_v2;
507	char *name;
508	bool is_v1v2;
509
510	MOD_SLOCK;
511	mod = module_lookupbyid(uap->modid);
512	if (mod == NULL) {
513		MOD_SUNLOCK;
514		return (ENOENT);
515	}
516
517	id = mod->id;
518	refs = mod->refs;
519	name = mod->name;
520	_Static_assert(sizeof(data32) == sizeof(data32.uintval),
521	    "bad modspecific32_t size");
522	CP(mod->data, data32, uintval);
523	MOD_SUNLOCK;
524	stat32 = uap->stat;
525
526	if ((error = copyin(&stat32->version, &version, sizeof(version))) != 0)
527		return (error);
528	is_v1v2 = (version == sizeof(struct module_stat_v1) ||
529	    version == sizeof(struct module_stat32_v2));
530	if (!is_v1v2 && version != sizeof(struct module_stat32))
531		return (EINVAL);
532	namelen = strlen(mod->name) + 1;
533	if (is_v1v2 && namelen > MAXMODNAMEV1V2)
534		namelen = MAXMODNAMEV1V2;
535	else if (namelen > MAXMODNAMEV3)
536		namelen = MAXMODNAMEV3;
537	if ((error = copyout(name, &stat32->name[0], namelen)) != 0)
538		return (error);
539
540	/* Extending MAXMODNAME gives an offset change for v3. */
541	if (is_v1v2) {
542		stat32_v2 = (struct module_stat32_v2 *)stat32;
543		if ((error = copyout(&refs, &stat32_v2->refs, sizeof(int))) != 0)
544			return (error);
545		if ((error = copyout(&id, &stat32_v2->id, sizeof(int))) != 0)
546			return (error);
547	} else {
548		if ((error = copyout(&refs, &stat32->refs, sizeof(int))) != 0)
549			return (error);
550		if ((error = copyout(&id, &stat32->id, sizeof(int))) != 0)
551			return (error);
552	}
553
554	/*
555	 * >v1 stat includes module data.
556	 */
557	if (version == sizeof(struct module_stat32_v2)) {
558		if ((error = copyout(&data32, &stat32_v2->data,
559		    sizeof(data32))) != 0)
560			return (error);
561	} else if (version == sizeof(struct module_stat32)) {
562		if ((error = copyout(&data32, &stat32->data,
563		    sizeof(data32))) != 0)
564			return (error);
565	}
566	td->td_retval[0] = 0;
567	return (error);
568}
569#endif
570