xref: /netbsd-src/sys/kern/kern_module.c (revision a0698ed9d41653d7a2378819ad501a285ca0d401)
1 /*	$NetBSD: kern_module.c,v 1.133 2019/01/27 02:08:43 pgoyette Exp $	*/
2 
3 /*-
4  * Copyright (c) 2008 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software developed for The NetBSD Foundation
8  * by Andrew Doran.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 /*
33  * Kernel module support.
34  */
35 
36 #include <sys/cdefs.h>
37 __KERNEL_RCSID(0, "$NetBSD: kern_module.c,v 1.133 2019/01/27 02:08:43 pgoyette Exp $");
38 
39 #define _MODULE_INTERNAL
40 
41 #ifdef _KERNEL_OPT
42 #include "opt_ddb.h"
43 #include "opt_modular.h"
44 #endif
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/kernel.h>
49 #include <sys/proc.h>
50 #include <sys/kauth.h>
51 #include <sys/kobj.h>
52 #include <sys/kmem.h>
53 #include <sys/module.h>
54 #include <sys/kthread.h>
55 #include <sys/sysctl.h>
56 #include <sys/lock.h>
57 
58 #include <uvm/uvm_extern.h>
59 
60 struct vm_map *module_map;
61 const char *module_machine;
62 char	module_base[MODULE_BASE_SIZE];
63 
64 struct modlist        module_list = TAILQ_HEAD_INITIALIZER(module_list);
65 struct modlist        module_builtins = TAILQ_HEAD_INITIALIZER(module_builtins);
66 static struct modlist module_bootlist = TAILQ_HEAD_INITIALIZER(module_bootlist);
67 
68 struct module_callbacks {
69 	TAILQ_ENTRY(module_callbacks) modcb_list;
70 	void (*modcb_load)(struct module *);
71 	void (*modcb_unload)(struct module *);
72 };
73 TAILQ_HEAD(modcblist, module_callbacks);
74 static struct modcblist modcblist;
75 
76 static module_t *module_netbsd;
77 static const modinfo_t module_netbsd_modinfo = {
78 	.mi_version = __NetBSD_Version__,
79 	.mi_class = MODULE_CLASS_MISC,
80 	.mi_name = "netbsd"
81 };
82 
83 static module_t	*module_active;
84 bool		module_verbose_on;
85 #ifdef MODULAR_DEFAULT_AUTOLOAD
86 bool		module_autoload_on = true;
87 #else
88 bool		module_autoload_on = false;
89 #endif
90 u_int		module_count;
91 u_int		module_builtinlist;
92 u_int		module_autotime = 10;
93 u_int		module_gen = 1;
94 static kcondvar_t module_thread_cv;
95 static kmutex_t module_thread_lock;
96 static int	module_thread_ticks;
97 int (*module_load_vfs_vec)(const char *, int, bool, module_t *,
98 			   prop_dictionary_t *) = (void *)eopnotsupp;
99 
100 static kauth_listener_t	module_listener;
101 
102 static specificdata_domain_t module_specificdata_domain;
103 
104 /* Ensure that the kernel's link set isn't empty. */
105 static modinfo_t module_dummy;
106 __link_set_add_rodata(modules, module_dummy);
107 
108 static module_t	*module_newmodule(modsrc_t);
109 static void	module_free(module_t *);
110 static void	module_require_force(module_t *);
111 static int	module_do_load(const char *, bool, int, prop_dictionary_t,
112 		    module_t **, modclass_t modclass, bool);
113 static int	module_do_unload(const char *, bool);
114 static int	module_do_builtin(const module_t *, const char *, module_t **,
115     prop_dictionary_t);
116 static int	module_fetch_info(module_t *);
117 static void	module_thread(void *);
118 
119 static module_t	*module_lookup(const char *);
120 static void	module_enqueue(module_t *);
121 
122 static bool	module_merge_dicts(prop_dictionary_t, const prop_dictionary_t);
123 
124 static void	sysctl_module_setup(void);
125 static int	sysctl_module_autotime(SYSCTLFN_PROTO);
126 
127 static void	module_callback_load(struct module *);
128 static void	module_callback_unload(struct module *);
129 
130 #define MODULE_CLASS_MATCH(mi, modclass) \
131 	((modclass) == MODULE_CLASS_ANY || (modclass) == (mi)->mi_class)
132 
133 static void
134 module_incompat(const modinfo_t *mi, int modclass)
135 {
136 	module_error("incompatible module class for `%s' (%d != %d)",
137 	    mi->mi_name, modclass, mi->mi_class);
138 }
139 
140 struct module *
141 module_kernel(void)
142 {
143 
144 	return module_netbsd;
145 }
146 
147 /*
148  * module_error:
149  *
150  *	Utility function: log an error.
151  */
152 void
153 module_error(const char *fmt, ...)
154 {
155 	va_list ap;
156 
157 	va_start(ap, fmt);
158 	printf("WARNING: module error: ");
159 	vprintf(fmt, ap);
160 	printf("\n");
161 	va_end(ap);
162 }
163 
164 /*
165  * module_print:
166  *
167  *	Utility function: log verbose output.
168  */
169 void
170 module_print(const char *fmt, ...)
171 {
172 	va_list ap;
173 
174 	if (module_verbose_on) {
175 		va_start(ap, fmt);
176 		printf("DEBUG: module: ");
177 		vprintf(fmt, ap);
178 		printf("\n");
179 		va_end(ap);
180 	}
181 }
182 
183 /*
184  * module_name:
185  *
186  *	Utility function: return the module's name.
187  */
188 const char *
189 module_name(struct module *mod)
190 {
191 
192 	return mod->mod_info->mi_name;
193 }
194 
195 /*
196  * module_source:
197  *
198  *	Utility function: return the module's source.
199  */
200 modsrc_t
201 module_source(struct module *mod)
202 {
203 
204 	return mod->mod_source;
205 }
206 
207 static int
208 module_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
209     void *arg0, void *arg1, void *arg2, void *arg3)
210 {
211 	int result;
212 
213 	result = KAUTH_RESULT_DEFER;
214 
215 	if (action != KAUTH_SYSTEM_MODULE)
216 		return result;
217 
218 	if ((uintptr_t)arg2 != 0)	/* autoload */
219 		result = KAUTH_RESULT_ALLOW;
220 
221 	return result;
222 }
223 
224 /*
225  * Allocate a new module_t
226  */
227 static module_t *
228 module_newmodule(modsrc_t source)
229 {
230 	module_t *mod;
231 
232 	mod = kmem_zalloc(sizeof(*mod), KM_SLEEP);
233 	mod->mod_source = source;
234 	specificdata_init(module_specificdata_domain, &mod->mod_sdref);
235 	return mod;
236 }
237 
238 /*
239  * Free a module_t
240  */
241 static void
242 module_free(module_t *mod)
243 {
244 
245 	specificdata_fini(module_specificdata_domain, &mod->mod_sdref);
246 	if (mod->mod_required)
247 		kmem_free(mod->mod_required, mod->mod_arequired *
248 		    sizeof(module_t *));
249 	kmem_free(mod, sizeof(*mod));
250 }
251 
252 /*
253  * Require the -f (force) flag to load a module
254  */
255 static void
256 module_require_force(struct module *mod)
257 {
258 	SET(mod->mod_flags, MODFLG_MUST_FORCE);
259 }
260 
261 /*
262  * Add modules to the builtin list.  This can done at boottime or
263  * at runtime if the module is linked into the kernel with an
264  * external linker.  All or none of the input will be handled.
265  * Optionally, the modules can be initialized.  If they are not
266  * initialized, module_init_class() or module_load() can be used
267  * later, but these are not guaranteed to give atomic results.
268  */
269 int
270 module_builtin_add(modinfo_t *const *mip, size_t nmodinfo, bool init)
271 {
272 	struct module **modp = NULL, *mod_iter;
273 	int rv = 0, i, mipskip;
274 
275 	if (init) {
276 		rv = kauth_authorize_system(kauth_cred_get(),
277 		    KAUTH_SYSTEM_MODULE, 0, (void *)(uintptr_t)MODCTL_LOAD,
278 		    (void *)(uintptr_t)1, NULL);
279 		if (rv) {
280 			return rv;
281 		}
282 	}
283 
284 	for (i = 0, mipskip = 0; i < nmodinfo; i++) {
285 		if (mip[i] == &module_dummy) {
286 			KASSERT(nmodinfo > 0);
287 			nmodinfo--;
288 		}
289 	}
290 	if (nmodinfo == 0)
291 		return 0;
292 
293 	modp = kmem_zalloc(sizeof(*modp) * nmodinfo, KM_SLEEP);
294 	for (i = 0, mipskip = 0; i < nmodinfo; i++) {
295 		if (mip[i+mipskip] == &module_dummy) {
296 			mipskip++;
297 			continue;
298 		}
299 		modp[i] = module_newmodule(MODULE_SOURCE_KERNEL);
300 		modp[i]->mod_info = mip[i+mipskip];
301 	}
302 	kernconfig_lock();
303 
304 	/* do this in three stages for error recovery and atomicity */
305 
306 	/* first check for presence */
307 	for (i = 0; i < nmodinfo; i++) {
308 		TAILQ_FOREACH(mod_iter, &module_builtins, mod_chain) {
309 			if (strcmp(mod_iter->mod_info->mi_name,
310 			    modp[i]->mod_info->mi_name) == 0)
311 				break;
312 		}
313 		if (mod_iter) {
314 			rv = EEXIST;
315 			goto out;
316 		}
317 
318 		if (module_lookup(modp[i]->mod_info->mi_name) != NULL) {
319 			rv = EEXIST;
320 			goto out;
321 		}
322 	}
323 
324 	/* then add to list */
325 	for (i = 0; i < nmodinfo; i++) {
326 		TAILQ_INSERT_TAIL(&module_builtins, modp[i], mod_chain);
327 		module_builtinlist++;
328 	}
329 
330 	/* finally, init (if required) */
331 	if (init) {
332 		for (i = 0; i < nmodinfo; i++) {
333 			rv = module_do_builtin(modp[i],
334 			    modp[i]->mod_info->mi_name, NULL, NULL);
335 			/* throw in the towel, recovery hard & not worth it */
336 			if (rv)
337 				panic("%s: builtin module \"%s\" init failed:"
338 				    " %d", __func__,
339 				    modp[i]->mod_info->mi_name, rv);
340 		}
341 	}
342 
343  out:
344 	kernconfig_unlock();
345 	if (rv != 0) {
346 		for (i = 0; i < nmodinfo; i++) {
347 			if (modp[i])
348 				module_free(modp[i]);
349 		}
350 	}
351 	kmem_free(modp, sizeof(*modp) * nmodinfo);
352 	return rv;
353 }
354 
355 /*
356  * Optionally fini and remove builtin module from the kernel.
357  * Note: the module will now be unreachable except via mi && builtin_add.
358  */
359 int
360 module_builtin_remove(modinfo_t *mi, bool fini)
361 {
362 	struct module *mod;
363 	int rv = 0;
364 
365 	if (fini) {
366 		rv = kauth_authorize_system(kauth_cred_get(),
367 		    KAUTH_SYSTEM_MODULE, 0, (void *)(uintptr_t)MODCTL_UNLOAD,
368 		    NULL, NULL);
369 		if (rv)
370 			return rv;
371 
372 		kernconfig_lock();
373 		rv = module_do_unload(mi->mi_name, true);
374 		if (rv) {
375 			goto out;
376 		}
377 	} else {
378 		kernconfig_lock();
379 	}
380 	TAILQ_FOREACH(mod, &module_builtins, mod_chain) {
381 		if (strcmp(mod->mod_info->mi_name, mi->mi_name) == 0)
382 			break;
383 	}
384 	if (mod) {
385 		TAILQ_REMOVE(&module_builtins, mod, mod_chain);
386 		module_builtinlist--;
387 	} else {
388 		KASSERT(fini == false);
389 		rv = ENOENT;
390 	}
391 
392  out:
393 	kernconfig_unlock();
394 	return rv;
395 }
396 
397 /*
398  * module_init:
399  *
400  *	Initialize the module subsystem.
401  */
402 void
403 module_init(void)
404 {
405 	__link_set_decl(modules, modinfo_t);
406 	extern struct vm_map *module_map;
407 	modinfo_t *const *mip;
408 	int rv;
409 
410 	if (module_map == NULL) {
411 		module_map = kernel_map;
412 	}
413 	cv_init(&module_thread_cv, "mod_unld");
414 	mutex_init(&module_thread_lock, MUTEX_DEFAULT, IPL_NONE);
415 	TAILQ_INIT(&modcblist);
416 
417 #ifdef MODULAR	/* XXX */
418 	module_init_md();
419 #endif
420 
421 	if (!module_machine)
422 		module_machine = machine;
423 #if __NetBSD_Version__ / 1000000 % 100 == 99	/* -current */
424 	snprintf(module_base, sizeof(module_base), "/stand/%s/%s/modules",
425 	    module_machine, osrelease);
426 #else						/* release */
427 	snprintf(module_base, sizeof(module_base), "/stand/%s/%d.%d/modules",
428 	    module_machine, __NetBSD_Version__ / 100000000,
429 	    __NetBSD_Version__ / 1000000 % 100);
430 #endif
431 
432 	module_listener = kauth_listen_scope(KAUTH_SCOPE_SYSTEM,
433 	    module_listener_cb, NULL);
434 
435 	__link_set_foreach(mip, modules) {
436 		if ((rv = module_builtin_add(mip, 1, false)) != 0)
437 			module_error("builtin %s failed: %d\n",
438 			    (*mip)->mi_name, rv);
439 	}
440 
441 	sysctl_module_setup();
442 	module_specificdata_domain = specificdata_domain_create();
443 
444 	module_netbsd = module_newmodule(MODULE_SOURCE_KERNEL);
445 	module_netbsd->mod_refcnt = 1;
446 	module_netbsd->mod_info = &module_netbsd_modinfo;
447 }
448 
449 /*
450  * module_start_unload_thread:
451  *
452  *	Start the auto unload kthread.
453  */
454 void
455 module_start_unload_thread(void)
456 {
457 	int error;
458 
459 	error = kthread_create(PRI_VM, KTHREAD_MPSAFE, NULL, module_thread,
460 	    NULL, NULL, "modunload");
461 	if (error != 0)
462 		panic("%s: %d", __func__, error);
463 }
464 
465 /*
466  * module_builtin_require_force
467  *
468  * Require MODCTL_MUST_FORCE to load any built-in modules that have
469  * not yet been initialized
470  */
471 void
472 module_builtin_require_force(void)
473 {
474 	module_t *mod;
475 
476 	kernconfig_lock();
477 	TAILQ_FOREACH(mod, &module_builtins, mod_chain) {
478 		module_require_force(mod);
479 	}
480 	kernconfig_unlock();
481 }
482 
483 static struct sysctllog *module_sysctllog;
484 
485 static int
486 sysctl_module_autotime(SYSCTLFN_ARGS)
487 {
488 	struct sysctlnode node;
489 	int t, error;
490 
491 	t = *(int *)rnode->sysctl_data;
492 
493 	node = *rnode;
494 	node.sysctl_data = &t;
495 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
496 	if (error || newp == NULL)
497 		return (error);
498 
499 	if (t < 0)
500 		return (EINVAL);
501 
502 	*(int *)rnode->sysctl_data = t;
503 	return (0);
504 }
505 
506 static void
507 sysctl_module_setup(void)
508 {
509 	const struct sysctlnode *node = NULL;
510 
511 	sysctl_createv(&module_sysctllog, 0, NULL, &node,
512 		CTLFLAG_PERMANENT,
513 		CTLTYPE_NODE, "module",
514 		SYSCTL_DESCR("Module options"),
515 		NULL, 0, NULL, 0,
516 		CTL_KERN, CTL_CREATE, CTL_EOL);
517 
518 	if (node == NULL)
519 		return;
520 
521 	sysctl_createv(&module_sysctllog, 0, &node, NULL,
522 		CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
523 		CTLTYPE_BOOL, "autoload",
524 		SYSCTL_DESCR("Enable automatic load of modules"),
525 		NULL, 0, &module_autoload_on, 0,
526 		CTL_CREATE, CTL_EOL);
527 	sysctl_createv(&module_sysctllog, 0, &node, NULL,
528 		CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
529 		CTLTYPE_BOOL, "verbose",
530 		SYSCTL_DESCR("Enable verbose output"),
531 		NULL, 0, &module_verbose_on, 0,
532 		CTL_CREATE, CTL_EOL);
533 	sysctl_createv(&module_sysctllog, 0, &node, NULL,
534 		CTLFLAG_PERMANENT | CTLFLAG_READONLY,
535 		CTLTYPE_STRING, "path",
536 		SYSCTL_DESCR("Default module load path"),
537 		NULL, 0, module_base, 0,
538 		CTL_CREATE, CTL_EOL);
539 	sysctl_createv(&module_sysctllog, 0, &node, NULL,
540 		CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
541 		CTLTYPE_INT, "autotime",
542 		SYSCTL_DESCR("Auto-unload delay"),
543 		sysctl_module_autotime, 0, &module_autotime, 0,
544 		CTL_CREATE, CTL_EOL);
545 }
546 
547 /*
548  * module_init_class:
549  *
550  *	Initialize all built-in and pre-loaded modules of the
551  *	specified class.
552  */
553 void
554 module_init_class(modclass_t modclass)
555 {
556 	TAILQ_HEAD(, module) bi_fail = TAILQ_HEAD_INITIALIZER(bi_fail);
557 	module_t *mod;
558 	modinfo_t *mi;
559 
560 	kernconfig_lock();
561 	/*
562 	 * Builtins first.  These will not depend on pre-loaded modules
563 	 * (because the kernel would not link).
564 	 */
565 	do {
566 		TAILQ_FOREACH(mod, &module_builtins, mod_chain) {
567 			mi = mod->mod_info;
568 			if (!MODULE_CLASS_MATCH(mi, modclass))
569 				continue;
570 			/*
571 			 * If initializing a builtin module fails, don't try
572 			 * to load it again.  But keep it around and queue it
573 			 * on the builtins list after we're done with module
574 			 * init.  Don't set it to MODFLG_MUST_FORCE in case a
575 			 * future attempt to initialize can be successful.
576 			 * (If the module has previously been set to
577 			 * MODFLG_MUST_FORCE, don't try to override that!)
578 			 */
579 			if (ISSET(mod->mod_flags, MODFLG_MUST_FORCE) ||
580 			    module_do_builtin(mod, mi->mi_name, NULL,
581 			    NULL) != 0) {
582 				TAILQ_REMOVE(&module_builtins, mod, mod_chain);
583 				TAILQ_INSERT_TAIL(&bi_fail, mod, mod_chain);
584 			}
585 			break;
586 		}
587 	} while (mod != NULL);
588 
589 	/*
590 	 * Now preloaded modules.  These will be pulled off the
591 	 * list as we call module_do_load();
592 	 */
593 	do {
594 		TAILQ_FOREACH(mod, &module_bootlist, mod_chain) {
595 			mi = mod->mod_info;
596 			if (!MODULE_CLASS_MATCH(mi, modclass))
597 				continue;
598 			module_do_load(mi->mi_name, false, 0, NULL, NULL,
599 			    modclass, false);
600 			break;
601 		}
602 	} while (mod != NULL);
603 
604 	/* return failed builtin modules to builtin list */
605 	while ((mod = TAILQ_FIRST(&bi_fail)) != NULL) {
606 		TAILQ_REMOVE(&bi_fail, mod, mod_chain);
607 		TAILQ_INSERT_TAIL(&module_builtins, mod, mod_chain);
608 	}
609 
610 	kernconfig_unlock();
611 }
612 
613 /*
614  * module_compatible:
615  *
616  *	Return true if the two supplied kernel versions are said to
617  *	have the same binary interface for kernel code.  The entire
618  *	version is signficant for the development tree (-current),
619  *	major and minor versions are significant for official
620  *	releases of the system.
621  */
622 bool
623 module_compatible(int v1, int v2)
624 {
625 
626 #if __NetBSD_Version__ / 1000000 % 100 == 99	/* -current */
627 	return v1 == v2;
628 #else						/* release */
629 	return abs(v1 - v2) < 10000;
630 #endif
631 }
632 
633 /*
634  * module_load:
635  *
636  *	Load a single module from the file system.
637  */
638 int
639 module_load(const char *filename, int flags, prop_dictionary_t props,
640 	    modclass_t modclass)
641 {
642 	module_t *mod;
643 	int error;
644 
645 	/* Test if we already have the module loaded before
646 	 * authorizing so we have the opportunity to return EEXIST. */
647 	kernconfig_lock();
648 	mod = module_lookup(filename);
649 	if (mod != NULL) {
650 		module_print("%s module `%s' already loaded",
651 		    "requested", filename);
652 		error = EEXIST;
653 		goto out;
654 	}
655 
656 	/* Authorize. */
657 	error = kauth_authorize_system(kauth_cred_get(), KAUTH_SYSTEM_MODULE,
658 	    0, (void *)(uintptr_t)MODCTL_LOAD, NULL, NULL);
659 	if (error != 0)
660 		goto out;
661 
662 	error = module_do_load(filename, false, flags, props, NULL, modclass,
663 	    false);
664 
665 out:
666 	kernconfig_unlock();
667 	return error;
668 }
669 
670 /*
671  * module_autoload:
672  *
673  *	Load a single module from the file system, system initiated.
674  */
675 int
676 module_autoload(const char *filename, modclass_t modclass)
677 {
678 	int error;
679 
680 	kernconfig_lock();
681 
682 	/* Nothing if the user has disabled it. */
683 	if (!module_autoload_on) {
684 		kernconfig_unlock();
685 		return EPERM;
686 	}
687 
688         /* Disallow path separators and magic symlinks. */
689         if (strchr(filename, '/') != NULL || strchr(filename, '@') != NULL ||
690             strchr(filename, '.') != NULL) {
691 		kernconfig_unlock();
692         	return EPERM;
693 	}
694 
695 	/* Authorize. */
696 	error = kauth_authorize_system(kauth_cred_get(), KAUTH_SYSTEM_MODULE,
697 	    0, (void *)(uintptr_t)MODCTL_LOAD, (void *)(uintptr_t)1, NULL);
698 
699 	if (error == 0)
700 		error = module_do_load(filename, false, 0, NULL, NULL, modclass,
701 		    true);
702 
703 	kernconfig_unlock();
704 	return error;
705 }
706 
707 /*
708  * module_unload:
709  *
710  *	Find and unload a module by name.
711  */
712 int
713 module_unload(const char *name)
714 {
715 	int error;
716 
717 	/* Authorize. */
718 	error = kauth_authorize_system(kauth_cred_get(), KAUTH_SYSTEM_MODULE,
719 	    0, (void *)(uintptr_t)MODCTL_UNLOAD, NULL, NULL);
720 	if (error != 0) {
721 		return error;
722 	}
723 
724 	kernconfig_lock();
725 	error = module_do_unload(name, true);
726 	kernconfig_unlock();
727 
728 	return error;
729 }
730 
731 /*
732  * module_lookup:
733  *
734  *	Look up a module by name.
735  */
736 module_t *
737 module_lookup(const char *name)
738 {
739 	module_t *mod;
740 
741 	KASSERT(kernconfig_is_held());
742 
743 	TAILQ_FOREACH(mod, &module_list, mod_chain) {
744 		if (strcmp(mod->mod_info->mi_name, name) == 0)
745 			break;
746 	}
747 
748 	return mod;
749 }
750 
751 /*
752  * module_hold:
753  *
754  *	Add a single reference to a module.  It's the caller's
755  *	responsibility to ensure that the reference is dropped
756  *	later.
757  */
758 void
759 module_hold(module_t *mod)
760 {
761 
762 	kernconfig_lock();
763 	mod->mod_refcnt++;
764 	kernconfig_unlock();
765 }
766 
767 /*
768  * module_rele:
769  *
770  *	Release a reference acquired with module_hold().
771  */
772 void
773 module_rele(module_t *mod)
774 {
775 
776 	kernconfig_lock();
777 	KASSERT(mod->mod_refcnt > 0);
778 	mod->mod_refcnt--;
779 	kernconfig_unlock();
780 }
781 
782 /*
783  * module_enqueue:
784  *
785  *	Put a module onto the global list and update counters.
786  */
787 void
788 module_enqueue(module_t *mod)
789 {
790 	int i;
791 
792 	KASSERT(kernconfig_is_held());
793 
794 	/*
795 	 * Put new entry at the head of the queue so autounload can unload
796 	 * requisite modules with only one pass through the queue.
797 	 */
798 	TAILQ_INSERT_HEAD(&module_list, mod, mod_chain);
799 	if (mod->mod_nrequired) {
800 
801 		/* Add references to the requisite modules. */
802 		for (i = 0; i < mod->mod_nrequired; i++) {
803 			KASSERT((*mod->mod_required)[i] != NULL);
804 			(*mod->mod_required)[i]->mod_refcnt++;
805 		}
806 	}
807 	module_count++;
808 	module_gen++;
809 }
810 
811 /*
812  * Our array of required module pointers starts with zero entries.  If we
813  * need to add a new entry, and the list is already full, we reallocate a
814  * larger array, adding MAXMODDEPS entries.
815  */
816 static void
817 alloc_required(module_t *mod)
818 {
819 	module_t *(*new)[], *(*old)[];
820 	int areq;
821 	int i;
822 
823 	if (mod->mod_nrequired >= mod->mod_arequired) {
824 		areq = mod->mod_arequired + MAXMODDEPS;
825 		old = mod->mod_required;
826 		new = kmem_zalloc(areq * sizeof(module_t *), KM_SLEEP);
827 		for (i = 0; i < mod->mod_arequired; i++)
828 			(*new)[i] = (*old)[i];
829 		mod->mod_required = new;
830 		if (old)
831 			kmem_free(old, mod->mod_arequired * sizeof(module_t *));
832 		mod->mod_arequired = areq;
833 	}
834 }
835 
836 /*
837  * module_do_builtin:
838  *
839  *	Initialize a module from the list of modules that are
840  *	already linked into the kernel.
841  */
842 static int
843 module_do_builtin(const module_t *pmod, const char *name, module_t **modp,
844     prop_dictionary_t props)
845 {
846 	const char *p, *s;
847 	char buf[MAXMODNAME];
848 	modinfo_t *mi = NULL;
849 	module_t *mod, *mod2, *mod_loaded, *prev_active;
850 	size_t len;
851 	int error;
852 
853 	KASSERT(kernconfig_is_held());
854 
855 	/*
856 	 * Search the list to see if we have a module by this name.
857 	 */
858 	TAILQ_FOREACH(mod, &module_builtins, mod_chain) {
859 		if (strcmp(mod->mod_info->mi_name, name) == 0) {
860 			mi = mod->mod_info;
861 			break;
862 		}
863 	}
864 
865 	/*
866 	 * Check to see if already loaded.  This might happen if we
867 	 * were already loaded as a dependency.
868 	 */
869 	if ((mod_loaded = module_lookup(name)) != NULL) {
870 		KASSERT(mod == NULL);
871 		if (modp)
872 			*modp = mod_loaded;
873 		return 0;
874 	}
875 
876 	/* Note! This is from TAILQ, not immediate above */
877 	if (mi == NULL) {
878 		/*
879 		 * XXX: We'd like to panic here, but currently in some
880 		 * cases (such as nfsserver + nfs), the dependee can be
881 		 * succesfully linked without the dependencies.
882 		 */
883 		module_error("built-in module %s can't find builtin "
884 		    "dependency `%s'", pmod->mod_info->mi_name, name);
885 		return ENOENT;
886 	}
887 
888 	/*
889 	 * Initialize pre-requisites.
890 	 */
891 	KASSERT(mod->mod_required == NULL);
892 	KASSERT(mod->mod_arequired == 0);
893 	KASSERT(mod->mod_nrequired == 0);
894 	if (mi->mi_required != NULL) {
895 		for (s = mi->mi_required; *s != '\0'; s = p) {
896 			if (*s == ',')
897 				s++;
898 			p = s;
899 			while (*p != '\0' && *p != ',')
900 				p++;
901 			len = uimin(p - s + 1, sizeof(buf));
902 			strlcpy(buf, s, len);
903 			if (buf[0] == '\0')
904 				break;
905 			alloc_required(mod);
906 			error = module_do_builtin(mod, buf, &mod2, NULL);
907 			if (error != 0) {
908 				module_error("built-in module %s prerequisite "
909 				    "%s failed, error %d", name, buf, error);
910 				goto fail;
911 			}
912 			(*mod->mod_required)[mod->mod_nrequired++] = mod2;
913 		}
914 	}
915 
916 	/*
917 	 * Try to initialize the module.
918 	 */
919 	prev_active = module_active;
920 	module_active = mod;
921 	error = (*mi->mi_modcmd)(MODULE_CMD_INIT, props);
922 	module_active = prev_active;
923 	if (error != 0) {
924 		module_error("built-in module %s failed its MODULE_CMD_INIT, "
925 		    "error %d", mi->mi_name, error);
926 		goto fail;
927 	}
928 
929 	/* load always succeeds after this point */
930 
931 	TAILQ_REMOVE(&module_builtins, mod, mod_chain);
932 	module_builtinlist--;
933 	if (modp != NULL) {
934 		*modp = mod;
935 	}
936 	module_enqueue(mod);
937 	return 0;
938 
939  fail:
940 	if (mod->mod_required)
941 		kmem_free(mod->mod_required, mod->mod_arequired *
942 		    sizeof(module_t *));
943 	mod->mod_arequired = 0;
944 	mod->mod_nrequired = 0;
945 	mod->mod_required = NULL;
946 	return error;
947 }
948 
949 /*
950  * module_do_load:
951  *
952  *	Helper routine: load a module from the file system, or one
953  *	pushed by the boot loader.
954  */
955 static int
956 module_do_load(const char *name, bool isdep, int flags,
957 	       prop_dictionary_t props, module_t **modp, modclass_t modclass,
958 	       bool autoload)
959 {
960 	/* The pending list for this level of recursion */
961 	TAILQ_HEAD(pending_t, module);
962 	struct pending_t *pending;
963 	struct pending_t new_pending = TAILQ_HEAD_INITIALIZER(new_pending);
964 
965 	/* The stack of pending lists */
966 	static SLIST_HEAD(pend_head, pend_entry) pend_stack =
967 		SLIST_HEAD_INITIALIZER(pend_stack);
968 	struct pend_entry {
969 		SLIST_ENTRY(pend_entry) pe_entry;
970 		struct pending_t *pe_pending;
971 	} my_pend_entry;
972 
973 	modinfo_t *mi;
974 	module_t *mod, *mod2, *prev_active;
975 	prop_dictionary_t filedict;
976 	char buf[MAXMODNAME];
977 	const char *s, *p;
978 	int error;
979 	size_t len;
980 
981 	KASSERT(kernconfig_is_held());
982 
983 	filedict = NULL;
984 	error = 0;
985 
986 	/*
987 	 * Set up the pending list for this entry.  If this is an
988 	 * internal entry (for a dependency), then use the same list
989 	 * as for the outer call;  otherwise, it's an external entry
990 	 * (possibly recursive, ie a module's xxx_modcmd(init, ...)
991 	 * routine called us), so use the locally allocated list.  In
992 	 * either case, add it to our stack.
993 	 */
994 	if (isdep) {
995 		KASSERT(SLIST_FIRST(&pend_stack) != NULL);
996 		pending = SLIST_FIRST(&pend_stack)->pe_pending;
997 	} else
998 		pending = &new_pending;
999 	my_pend_entry.pe_pending = pending;
1000 	SLIST_INSERT_HEAD(&pend_stack, &my_pend_entry, pe_entry);
1001 
1002 	/*
1003 	 * Search the list of disabled builtins first.
1004 	 */
1005 	TAILQ_FOREACH(mod, &module_builtins, mod_chain) {
1006 		if (strcmp(mod->mod_info->mi_name, name) == 0) {
1007 			break;
1008 		}
1009 	}
1010 	if (mod) {
1011 		if (ISSET(mod->mod_flags, MODFLG_MUST_FORCE) &&
1012 		    !ISSET(flags, MODCTL_LOAD_FORCE)) {
1013 			if (!autoload) {
1014 				module_error("use -f to reinstate "
1015 				    "builtin module `%s'", name);
1016 			}
1017 			SLIST_REMOVE_HEAD(&pend_stack, pe_entry);
1018 			return EPERM;
1019 		} else {
1020 			SLIST_REMOVE_HEAD(&pend_stack, pe_entry);
1021 			error = module_do_builtin(mod, name, modp, props);
1022 			return error;
1023 		}
1024 	}
1025 
1026 	/*
1027 	 * Load the module and link.  Before going to the file system,
1028 	 * scan the list of modules loaded by the boot loader.
1029 	 */
1030 	TAILQ_FOREACH(mod, &module_bootlist, mod_chain) {
1031 		if (strcmp(mod->mod_info->mi_name, name) == 0) {
1032 			TAILQ_REMOVE(&module_bootlist, mod, mod_chain);
1033 			break;
1034 		}
1035 	}
1036 	if (mod != NULL) {
1037 		TAILQ_INSERT_TAIL(pending, mod, mod_chain);
1038 	} else {
1039 		/*
1040 		 * Check to see if module is already present.
1041 		 */
1042 		mod = module_lookup(name);
1043 		if (mod != NULL) {
1044 			if (modp != NULL) {
1045 				*modp = mod;
1046 			}
1047 			module_print("%s module `%s' already loaded",
1048 			    isdep ? "dependent" : "requested", name);
1049 			SLIST_REMOVE_HEAD(&pend_stack, pe_entry);
1050 			return EEXIST;
1051 		}
1052 
1053 		mod = module_newmodule(MODULE_SOURCE_FILESYS);
1054 		if (mod == NULL) {
1055 			module_error("out of memory for `%s'", name);
1056 			SLIST_REMOVE_HEAD(&pend_stack, pe_entry);
1057 			return ENOMEM;
1058 		}
1059 
1060 		error = module_load_vfs_vec(name, flags, autoload, mod,
1061 					    &filedict);
1062 		if (error != 0) {
1063 #ifdef DEBUG
1064 			/*
1065 			 * The exec class of modules contains a list of
1066 			 * modules that is the union of all the modules
1067 			 * available for each architecture, so we don't
1068 			 * print an error if they are missing.
1069 			 */
1070 			if ((modclass != MODULE_CLASS_EXEC || error != ENOENT)
1071 			    && root_device != NULL)
1072 				module_error("vfs load failed for `%s', "
1073 				    "error %d", name, error);
1074 #endif
1075 			SLIST_REMOVE_HEAD(&pend_stack, pe_entry);
1076 			module_free(mod);
1077 			return error;
1078 		}
1079 		TAILQ_INSERT_TAIL(pending, mod, mod_chain);
1080 
1081 		error = module_fetch_info(mod);
1082 		if (error != 0) {
1083 			module_error("cannot fetch info for `%s', error %d",
1084 			    name, error);
1085 			goto fail;
1086 		}
1087 	}
1088 
1089 	/*
1090 	 * Check compatibility.
1091 	 */
1092 	mi = mod->mod_info;
1093 	if (strlen(mi->mi_name) >= MAXMODNAME) {
1094 		error = EINVAL;
1095 		module_error("module name `%s' longer than %d", mi->mi_name,
1096 		    MAXMODNAME);
1097 		goto fail;
1098 	}
1099 	if (!module_compatible(mi->mi_version, __NetBSD_Version__)) {
1100 		module_error("module `%s' built for `%d', system `%d'",
1101 		    mi->mi_name, mi->mi_version, __NetBSD_Version__);
1102 		if (ISSET(flags, MODCTL_LOAD_FORCE)) {
1103 			module_error("forced load, system may be unstable");
1104 		} else {
1105 			error = EPROGMISMATCH;
1106 			goto fail;
1107 		}
1108 	}
1109 
1110 	/*
1111 	 * If a specific kind of module was requested, ensure that we have
1112 	 * a match.
1113 	 */
1114 	if (!MODULE_CLASS_MATCH(mi, modclass)) {
1115 		module_incompat(mi, modclass);
1116 		error = ENOENT;
1117 		goto fail;
1118 	}
1119 
1120 	/*
1121 	 * If loading a dependency, `name' is a plain module name.
1122 	 * The name must match.
1123 	 */
1124 	if (isdep && strcmp(mi->mi_name, name) != 0) {
1125 		module_error("dependency name mismatch (`%s' != `%s')",
1126 		    name, mi->mi_name);
1127 		error = ENOENT;
1128 		goto fail;
1129 	}
1130 
1131 	/*
1132 	 * If we loaded a module from the filesystem, check the actual
1133 	 * module name (from the modinfo_t) to ensure another module
1134 	 * with the same name doesn't already exist.  (There's no
1135 	 * guarantee the filename will match the module name, and the
1136 	 * dup-symbols check may not be sufficient.)
1137 	 */
1138 	if (mod->mod_source == MODULE_SOURCE_FILESYS) {
1139 		mod2 = module_lookup(mod->mod_info->mi_name);
1140 		if ( mod2 && mod2 != mod) {
1141 			module_error("module with name `%s' already loaded",
1142 			    mod2->mod_info->mi_name);
1143 			error = EEXIST;
1144 			if (modp != NULL)
1145 				*modp = mod2;
1146 			goto fail;
1147 		}
1148 	}
1149 
1150 	/*
1151 	 * Block circular dependencies.
1152 	 */
1153 	TAILQ_FOREACH(mod2, pending, mod_chain) {
1154 		if (mod == mod2) {
1155 			continue;
1156 		}
1157 		if (strcmp(mod2->mod_info->mi_name, mi->mi_name) == 0) {
1158 			error = EDEADLK;
1159 			module_error("circular dependency detected for `%s'",
1160 			    mi->mi_name);
1161 			goto fail;
1162 		}
1163 	}
1164 
1165 	/*
1166 	 * Now try to load any requisite modules.
1167 	 */
1168 	if (mi->mi_required != NULL) {
1169 		mod->mod_arequired = 0;
1170 		for (s = mi->mi_required; *s != '\0'; s = p) {
1171 			if (*s == ',')
1172 				s++;
1173 			p = s;
1174 			while (*p != '\0' && *p != ',')
1175 				p++;
1176 			len = p - s + 1;
1177 			if (len >= MAXMODNAME) {
1178 				error = EINVAL;
1179 				module_error("required module name `%s' "
1180 				    "longer than %d", mi->mi_required,
1181 				    MAXMODNAME);
1182 				goto fail;
1183 			}
1184 			strlcpy(buf, s, len);
1185 			if (buf[0] == '\0')
1186 				break;
1187 			alloc_required(mod);
1188 			if (strcmp(buf, mi->mi_name) == 0) {
1189 				error = EDEADLK;
1190 				module_error("self-dependency detected for "
1191 				   "`%s'", mi->mi_name);
1192 				goto fail;
1193 			}
1194 			error = module_do_load(buf, true, flags, NULL,
1195 			    &mod2, MODULE_CLASS_ANY, true);
1196 			if (error != 0 && error != EEXIST) {
1197 				module_error("recursive load failed for `%s' "
1198 				    "(`%s' required), error %d", mi->mi_name,
1199 				    buf, error);
1200 				goto fail;
1201 			}
1202 			(*mod->mod_required)[mod->mod_nrequired++] = mod2;
1203 		}
1204 	}
1205 
1206 	/*
1207 	 * We loaded all needed modules successfully: perform global
1208 	 * relocations and initialize.
1209 	 */
1210 	error = kobj_affix(mod->mod_kobj, mi->mi_name);
1211 	if (error != 0) {
1212 		/* Cannot touch 'mi' as the module is now gone. */
1213 		module_error("unable to affix module `%s', error %d", name,
1214 		    error);
1215 		goto fail2;
1216 	}
1217 
1218 	if (filedict) {
1219 		if (!module_merge_dicts(filedict, props)) {
1220 			module_error("module properties failed for %s", name);
1221 			error = EINVAL;
1222 			goto fail;
1223 		}
1224 	}
1225 
1226 	prev_active = module_active;
1227 	module_active = mod;
1228 	error = (*mi->mi_modcmd)(MODULE_CMD_INIT, filedict ? filedict : props);
1229 	module_active = prev_active;
1230 	if (filedict) {
1231 		prop_object_release(filedict);
1232 		filedict = NULL;
1233 	}
1234 	if (error != 0) {
1235 		module_error("modcmd function failed for `%s', error %d",
1236 		    mi->mi_name, error);
1237 		goto fail;
1238 	}
1239 
1240 	/*
1241 	 * If a recursive load already added a module with the same
1242 	 * name, abort.
1243 	 */
1244 	mod2 = module_lookup(mi->mi_name);
1245 	if (mod2 && mod2 != mod) {
1246 		module_error("recursive load causes duplicate module `%s'",
1247 		    mi->mi_name);
1248 		error = EEXIST;
1249 		goto fail1;
1250 	}
1251 
1252 	/*
1253 	 * Good, the module loaded successfully.  Put it onto the
1254 	 * list and add references to its requisite modules.
1255 	 */
1256 	TAILQ_REMOVE(pending, mod, mod_chain);
1257 	module_enqueue(mod);
1258 	if (modp != NULL) {
1259 		*modp = mod;
1260 	}
1261 	if (autoload && module_autotime > 0) {
1262 		/*
1263 		 * Arrange to try unloading the module after
1264 		 * a short delay unless auto-unload is disabled.
1265 		 */
1266 		mod->mod_autotime = time_second + module_autotime;
1267 		SET(mod->mod_flags, MODFLG_AUTO_LOADED);
1268 		module_thread_kick();
1269 	}
1270 	SLIST_REMOVE_HEAD(&pend_stack, pe_entry);
1271 	module_print("module `%s' loaded successfully", mi->mi_name);
1272 	module_callback_load(mod);
1273 	return 0;
1274 
1275  fail1:
1276 	(*mi->mi_modcmd)(MODULE_CMD_FINI, NULL);
1277  fail:
1278 	kobj_unload(mod->mod_kobj);
1279  fail2:
1280 	if (filedict != NULL) {
1281 		prop_object_release(filedict);
1282 		filedict = NULL;
1283 	}
1284 	TAILQ_REMOVE(pending, mod, mod_chain);
1285 	SLIST_REMOVE_HEAD(&pend_stack, pe_entry);
1286 	module_free(mod);
1287 	return error;
1288 }
1289 
1290 /*
1291  * module_do_unload:
1292  *
1293  *	Helper routine: do the dirty work of unloading a module.
1294  */
1295 static int
1296 module_do_unload(const char *name, bool load_requires_force)
1297 {
1298 	module_t *mod, *prev_active;
1299 	int error;
1300 	u_int i;
1301 
1302 	KASSERT(kernconfig_is_held());
1303 	KASSERT(name != NULL);
1304 
1305 	module_print("unload requested for '%s' (%s)", name,
1306 	    load_requires_force ? "TRUE" : "FALSE");
1307 	mod = module_lookup(name);
1308 	if (mod == NULL) {
1309 		module_error("module `%s' not found", name);
1310 		return ENOENT;
1311 	}
1312 	if (mod->mod_refcnt != 0) {
1313 		module_print("module `%s' busy (%d refs)", name,
1314 		    mod->mod_refcnt);
1315 		return EBUSY;
1316 	}
1317 
1318 	/*
1319 	 * Builtin secmodels are there to stay.
1320 	 */
1321 	if (mod->mod_source == MODULE_SOURCE_KERNEL &&
1322 	    mod->mod_info->mi_class == MODULE_CLASS_SECMODEL) {
1323 		module_print("cannot unload built-in secmodel module `%s'",
1324 		    name);
1325 		return EPERM;
1326 	}
1327 
1328 	prev_active = module_active;
1329 	module_active = mod;
1330 	module_callback_unload(mod);
1331 	error = (*mod->mod_info->mi_modcmd)(MODULE_CMD_FINI, NULL);
1332 	module_active = prev_active;
1333 	if (error != 0) {
1334 		module_print("cannot unload module `%s' error=%d", name,
1335 		    error);
1336 		return error;
1337 	}
1338 	module_count--;
1339 	TAILQ_REMOVE(&module_list, mod, mod_chain);
1340 	for (i = 0; i < mod->mod_nrequired; i++) {
1341 		(*mod->mod_required)[i]->mod_refcnt--;
1342 	}
1343 	module_print("unloaded module `%s'", name);
1344 	if (mod->mod_kobj != NULL) {
1345 		kobj_unload(mod->mod_kobj);
1346 	}
1347 	if (mod->mod_source == MODULE_SOURCE_KERNEL) {
1348 		if (mod->mod_required != NULL) {
1349 			/*
1350 			 * release "required" resources - will be re-parsed
1351 			 * if the module is re-enabled
1352 			 */
1353 			kmem_free(mod->mod_required,
1354 			    mod->mod_arequired * sizeof(module_t *));
1355 			mod->mod_nrequired = 0;
1356 			mod->mod_arequired = 0;
1357 			mod->mod_required = NULL;
1358 		}
1359 		if (load_requires_force)
1360 			module_require_force(mod);
1361 		TAILQ_INSERT_TAIL(&module_builtins, mod, mod_chain);
1362 		module_builtinlist++;
1363 	} else {
1364 		module_free(mod);
1365 	}
1366 	module_gen++;
1367 
1368 	return 0;
1369 }
1370 
1371 /*
1372  * module_prime:
1373  *
1374  *	Push a module loaded by the bootloader onto our internal
1375  *	list.
1376  */
1377 int
1378 module_prime(const char *name, void *base, size_t size)
1379 {
1380 	__link_set_decl(modules, modinfo_t);
1381 	modinfo_t *const *mip;
1382 	module_t *mod;
1383 	int error;
1384 
1385 	/* Check for module name same as a built-in module */
1386 
1387 	__link_set_foreach(mip, modules) {
1388 		if (*mip == &module_dummy)
1389 			continue;
1390 		if (strcmp((*mip)->mi_name, name) == 0) {
1391 			module_error("module `%s' pushed by boot loader "
1392 			    "already exists", name);
1393 			return EEXIST;
1394 		}
1395 	}
1396 
1397 	/* Also eliminate duplicate boolist entries */
1398 
1399 	TAILQ_FOREACH(mod, &module_bootlist, mod_chain) {
1400 		if (strcmp(mod->mod_info->mi_name, name) == 0) {
1401 			module_error("duplicate bootlist entry for module "
1402 			    "`%s'", name);
1403 			return EEXIST;
1404 		}
1405 	}
1406 
1407 	mod = module_newmodule(MODULE_SOURCE_BOOT);
1408 	if (mod == NULL) {
1409 		return ENOMEM;
1410 	}
1411 
1412 	error = kobj_load_mem(&mod->mod_kobj, name, base, size);
1413 	if (error != 0) {
1414 		module_free(mod);
1415 		module_error("unable to load `%s' pushed by boot loader, "
1416 		    "error %d", name, error);
1417 		return error;
1418 	}
1419 	error = module_fetch_info(mod);
1420 	if (error != 0) {
1421 		kobj_unload(mod->mod_kobj);
1422 		module_free(mod);
1423 		module_error("unable to fetch_info for `%s' pushed by boot "
1424 		    "loader, error %d", name, error);
1425 		return error;
1426 	}
1427 
1428 	TAILQ_INSERT_TAIL(&module_bootlist, mod, mod_chain);
1429 
1430 	return 0;
1431 }
1432 
1433 /*
1434  * module_fetch_into:
1435  *
1436  *	Fetch modinfo record from a loaded module.
1437  */
1438 static int
1439 module_fetch_info(module_t *mod)
1440 {
1441 	int error;
1442 	void *addr;
1443 	size_t size;
1444 
1445 	/*
1446 	 * Find module info record and check compatibility.
1447 	 */
1448 	error = kobj_find_section(mod->mod_kobj, "link_set_modules",
1449 	    &addr, &size);
1450 	if (error != 0) {
1451 		module_error("`link_set_modules' section not present, "
1452 		    "error %d", error);
1453 		return error;
1454 	}
1455 	if (size != sizeof(modinfo_t **)) {
1456 		module_error("`link_set_modules' section wrong size "
1457 		    "(got %zu, wanted %zu)", size, sizeof(modinfo_t **));
1458 		return ENOEXEC;
1459 	}
1460 	mod->mod_info = *(modinfo_t **)addr;
1461 
1462 	return 0;
1463 }
1464 
1465 /*
1466  * module_find_section:
1467  *
1468  *	Allows a module that is being initialized to look up a section
1469  *	within its ELF object.
1470  */
1471 int
1472 module_find_section(const char *name, void **addr, size_t *size)
1473 {
1474 
1475 	KASSERT(kernconfig_is_held());
1476 	KASSERT(module_active != NULL);
1477 
1478 	return kobj_find_section(module_active->mod_kobj, name, addr, size);
1479 }
1480 
1481 /*
1482  * module_thread:
1483  *
1484  *	Automatically unload modules.  We try once to unload autoloaded
1485  *	modules after module_autotime seconds.  If the system is under
1486  *	severe memory pressure, we'll try unloading all modules, else if
1487  *	module_autotime is zero, we don't try to unload, even if the
1488  *	module was previously scheduled for unload.
1489  */
1490 static void
1491 module_thread(void *cookie)
1492 {
1493 	module_t *mod, *next;
1494 	modinfo_t *mi;
1495 	int error;
1496 
1497 	for (;;) {
1498 		kernconfig_lock();
1499 		for (mod = TAILQ_FIRST(&module_list); mod != NULL; mod = next) {
1500 			next = TAILQ_NEXT(mod, mod_chain);
1501 
1502 			/* skip built-in modules */
1503 			if (mod->mod_source == MODULE_SOURCE_KERNEL)
1504 				continue;
1505 			/* skip modules that weren't auto-loaded */
1506 			if (!ISSET(mod->mod_flags, MODFLG_AUTO_LOADED))
1507 				continue;
1508 
1509 			if (uvmexp.free < uvmexp.freemin) {
1510 				module_thread_ticks = hz;
1511 			} else if (module_autotime == 0 ||
1512 				   mod->mod_autotime == 0) {
1513 				continue;
1514 			} else if (time_second < mod->mod_autotime) {
1515 				module_thread_ticks = hz;
1516 			    	continue;
1517 			} else {
1518 				mod->mod_autotime = 0;
1519 			}
1520 
1521 			/*
1522 			 * If this module wants to avoid autounload then
1523 			 * skip it.  Some modules can ping-pong in and out
1524 			 * because their use is transient but often.
1525 			 * Example: exec_script.
1526 			 */
1527 			mi = mod->mod_info;
1528 			error = (*mi->mi_modcmd)(MODULE_CMD_AUTOUNLOAD, NULL);
1529 			if (error == 0 || error == ENOTTY) {
1530 				(void)module_do_unload(mi->mi_name, false);
1531 			} else
1532 				module_print("module `%s' declined to be "
1533 				    "auto-unloaded error=%d", mi->mi_name,
1534 				    error);
1535 		}
1536 		kernconfig_unlock();
1537 
1538 		mutex_enter(&module_thread_lock);
1539 		(void)cv_timedwait(&module_thread_cv, &module_thread_lock,
1540 		    module_thread_ticks);
1541 		module_thread_ticks = 0;
1542 		mutex_exit(&module_thread_lock);
1543 	}
1544 }
1545 
1546 /*
1547  * module_thread:
1548  *
1549  *	Kick the module thread into action, perhaps because the
1550  *	system is low on memory.
1551  */
1552 void
1553 module_thread_kick(void)
1554 {
1555 
1556 	mutex_enter(&module_thread_lock);
1557 	module_thread_ticks = hz;
1558 	cv_broadcast(&module_thread_cv);
1559 	mutex_exit(&module_thread_lock);
1560 }
1561 
1562 #ifdef DDB
1563 /*
1564  * module_whatis:
1565  *
1566  *	Helper routine for DDB.
1567  */
1568 void
1569 module_whatis(uintptr_t addr, void (*pr)(const char *, ...))
1570 {
1571 	module_t *mod;
1572 	size_t msize;
1573 	vaddr_t maddr;
1574 
1575 	TAILQ_FOREACH(mod, &module_list, mod_chain) {
1576 		if (mod->mod_kobj == NULL) {
1577 			continue;
1578 		}
1579 		if (kobj_stat(mod->mod_kobj, &maddr, &msize) != 0)
1580 			continue;
1581 		if (addr < maddr || addr >= maddr + msize) {
1582 			continue;
1583 		}
1584 		(*pr)("%p is %p+%zu, in kernel module `%s'\n",
1585 		    (void *)addr, (void *)maddr,
1586 		    (size_t)(addr - maddr), mod->mod_info->mi_name);
1587 	}
1588 }
1589 
1590 /*
1591  * module_print_list:
1592  *
1593  *	Helper routine for DDB.
1594  */
1595 void
1596 module_print_list(void (*pr)(const char *, ...))
1597 {
1598 	const char *src;
1599 	module_t *mod;
1600 	size_t msize;
1601 	vaddr_t maddr;
1602 
1603 	(*pr)("%16s %16s %8s %8s\n", "NAME", "TEXT/DATA", "SIZE", "SOURCE");
1604 
1605 	TAILQ_FOREACH(mod, &module_list, mod_chain) {
1606 		switch (mod->mod_source) {
1607 		case MODULE_SOURCE_KERNEL:
1608 			src = "builtin";
1609 			break;
1610 		case MODULE_SOURCE_FILESYS:
1611 			src = "filesys";
1612 			break;
1613 		case MODULE_SOURCE_BOOT:
1614 			src = "boot";
1615 			break;
1616 		default:
1617 			src = "unknown";
1618 			break;
1619 		}
1620 		if (mod->mod_kobj == NULL) {
1621 			maddr = 0;
1622 			msize = 0;
1623 		} else if (kobj_stat(mod->mod_kobj, &maddr, &msize) != 0)
1624 			continue;
1625 		(*pr)("%16s %16lx %8ld %8s\n", mod->mod_info->mi_name,
1626 		    (long)maddr, (long)msize, src);
1627 	}
1628 }
1629 #endif	/* DDB */
1630 
1631 static bool
1632 module_merge_dicts(prop_dictionary_t existing_dict,
1633 		   const prop_dictionary_t new_dict)
1634 {
1635 	prop_dictionary_keysym_t props_keysym;
1636 	prop_object_iterator_t props_iter;
1637 	prop_object_t props_obj;
1638 	const char *props_key;
1639 	bool error;
1640 
1641 	if (new_dict == NULL) {			/* nothing to merge */
1642 		return true;
1643 	}
1644 
1645 	error = false;
1646 	props_iter = prop_dictionary_iterator(new_dict);
1647 	if (props_iter == NULL) {
1648 		return false;
1649 	}
1650 
1651 	while ((props_obj = prop_object_iterator_next(props_iter)) != NULL) {
1652 		props_keysym = (prop_dictionary_keysym_t)props_obj;
1653 		props_key = prop_dictionary_keysym_cstring_nocopy(props_keysym);
1654 		props_obj = prop_dictionary_get_keysym(new_dict, props_keysym);
1655 		if ((props_obj == NULL) || !prop_dictionary_set(existing_dict,
1656 		    props_key, props_obj)) {
1657 			error = true;
1658 			goto out;
1659 		}
1660 	}
1661 	error = false;
1662 
1663 out:
1664 	prop_object_iterator_release(props_iter);
1665 
1666 	return !error;
1667 }
1668 
1669 /*
1670  * module_specific_key_create:
1671  *
1672  *	Create a key for subsystem module-specific data.
1673  */
1674 specificdata_key_t
1675 module_specific_key_create(specificdata_key_t *keyp, specificdata_dtor_t dtor)
1676 {
1677 
1678 	return specificdata_key_create(module_specificdata_domain, keyp, dtor);
1679 }
1680 
1681 /*
1682  * module_specific_key_delete:
1683  *
1684  *	Delete a key for subsystem module-specific data.
1685  */
1686 void
1687 module_specific_key_delete(specificdata_key_t key)
1688 {
1689 
1690 	return specificdata_key_delete(module_specificdata_domain, key);
1691 }
1692 
1693 /*
1694  * module_getspecific:
1695  *
1696  *	Return module-specific data corresponding to the specified key.
1697  */
1698 void *
1699 module_getspecific(module_t *mod, specificdata_key_t key)
1700 {
1701 
1702 	return specificdata_getspecific(module_specificdata_domain,
1703 	    &mod->mod_sdref, key);
1704 }
1705 
1706 /*
1707  * module_setspecific:
1708  *
1709  *	Set module-specific data corresponding to the specified key.
1710  */
1711 void
1712 module_setspecific(module_t *mod, specificdata_key_t key, void *data)
1713 {
1714 
1715 	specificdata_setspecific(module_specificdata_domain,
1716 	    &mod->mod_sdref, key, data);
1717 }
1718 
1719 /*
1720  * module_register_callbacks:
1721  *
1722  *	Register a new set of callbacks to be called on module load/unload.
1723  *	Call the load callback on each existing module.
1724  *	Return an opaque handle for unregistering these later.
1725  */
1726 void *
1727 module_register_callbacks(void (*load)(struct module *),
1728     void (*unload)(struct module *))
1729 {
1730 	struct module_callbacks *modcb;
1731 	struct module *mod;
1732 
1733 	modcb = kmem_alloc(sizeof(*modcb), KM_SLEEP);
1734 	modcb->modcb_load = load;
1735 	modcb->modcb_unload = unload;
1736 
1737 	kernconfig_lock();
1738 	TAILQ_INSERT_TAIL(&modcblist, modcb, modcb_list);
1739 	TAILQ_FOREACH(mod, &module_list, mod_chain)
1740 		load(mod);
1741 	kernconfig_unlock();
1742 
1743 	return modcb;
1744 }
1745 
1746 /*
1747  * module_unregister_callbacks:
1748  *
1749  *	Unregister a previously-registered set of module load/unload callbacks.
1750  *	Call the unload callback on each existing module.
1751  */
1752 void
1753 module_unregister_callbacks(void *opaque)
1754 {
1755 	struct module_callbacks *modcb;
1756 	struct module *mod;
1757 
1758 	modcb = opaque;
1759 	kernconfig_lock();
1760 	TAILQ_FOREACH(mod, &module_list, mod_chain)
1761 		modcb->modcb_unload(mod);
1762 	TAILQ_REMOVE(&modcblist, modcb, modcb_list);
1763 	kernconfig_unlock();
1764 	kmem_free(modcb, sizeof(*modcb));
1765 }
1766 
1767 /*
1768  * module_callback_load:
1769  *
1770  *	Helper routine: call all load callbacks on a module being loaded.
1771  */
1772 static void
1773 module_callback_load(struct module *mod)
1774 {
1775 	struct module_callbacks *modcb;
1776 
1777 	TAILQ_FOREACH(modcb, &modcblist, modcb_list) {
1778 		modcb->modcb_load(mod);
1779 	}
1780 }
1781 
1782 /*
1783  * module_callback_unload:
1784  *
1785  *	Helper routine: call all unload callbacks on a module being unloaded.
1786  */
1787 static void
1788 module_callback_unload(struct module *mod)
1789 {
1790 	struct module_callbacks *modcb;
1791 
1792 	TAILQ_FOREACH(modcb, &modcblist, modcb_list) {
1793 		modcb->modcb_unload(mod);
1794 	}
1795 }
1796