xref: /freebsd/sys/kern/kern_linker.c (revision b19c9dea3ec011ea419f91b5489f0572c2169ca5)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 1997-2000 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/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "opt_ddb.h"
33 #include "opt_kld.h"
34 #include "opt_hwpmc_hooks.h"
35 
36 #include <sys/param.h>
37 #include <sys/kernel.h>
38 #include <sys/systm.h>
39 #include <sys/malloc.h>
40 #include <sys/sysproto.h>
41 #include <sys/sysent.h>
42 #include <sys/priv.h>
43 #include <sys/proc.h>
44 #include <sys/lock.h>
45 #include <sys/mutex.h>
46 #include <sys/sx.h>
47 #include <sys/module.h>
48 #include <sys/mount.h>
49 #include <sys/linker.h>
50 #include <sys/eventhandler.h>
51 #include <sys/fcntl.h>
52 #include <sys/jail.h>
53 #include <sys/libkern.h>
54 #include <sys/namei.h>
55 #include <sys/vnode.h>
56 #include <sys/syscallsubr.h>
57 #include <sys/sysctl.h>
58 
59 #ifdef DDB
60 #include <ddb/ddb.h>
61 #endif
62 
63 #include <net/vnet.h>
64 
65 #include <security/mac/mac_framework.h>
66 
67 #include "linker_if.h"
68 
69 #ifdef HWPMC_HOOKS
70 #include <sys/pmckern.h>
71 #endif
72 
73 #ifdef KLD_DEBUG
74 int kld_debug = 0;
75 SYSCTL_INT(_debug, OID_AUTO, kld_debug, CTLFLAG_RWTUN,
76     &kld_debug, 0, "Set various levels of KLD debug");
77 #endif
78 
79 /* These variables are used by kernel debuggers to enumerate loaded files. */
80 const int kld_off_address = offsetof(struct linker_file, address);
81 const int kld_off_filename = offsetof(struct linker_file, filename);
82 const int kld_off_pathname = offsetof(struct linker_file, pathname);
83 const int kld_off_next = offsetof(struct linker_file, link.tqe_next);
84 
85 /*
86  * static char *linker_search_path(const char *name, struct mod_depend
87  * *verinfo);
88  */
89 static const char 	*linker_basename(const char *path);
90 
91 /*
92  * Find a currently loaded file given its filename.
93  */
94 static linker_file_t linker_find_file_by_name(const char* _filename);
95 
96 /*
97  * Find a currently loaded file given its file id.
98  */
99 static linker_file_t linker_find_file_by_id(int _fileid);
100 
101 /* Metadata from the static kernel */
102 SET_DECLARE(modmetadata_set, struct mod_metadata);
103 
104 MALLOC_DEFINE(M_LINKER, "linker", "kernel linker");
105 
106 linker_file_t linker_kernel_file;
107 
108 static struct sx kld_sx;	/* kernel linker lock */
109 
110 /*
111  * Load counter used by clients to determine if a linker file has been
112  * re-loaded. This counter is incremented for each file load.
113  */
114 static int loadcnt;
115 
116 static linker_class_list_t classes;
117 static linker_file_list_t linker_files;
118 static int next_file_id = 1;
119 static int linker_no_more_classes = 0;
120 
121 #define	LINKER_GET_NEXT_FILE_ID(a) do {					\
122 	linker_file_t lftmp;						\
123 									\
124 	if (!cold)							\
125 		sx_assert(&kld_sx, SA_XLOCKED);				\
126 retry:									\
127 	TAILQ_FOREACH(lftmp, &linker_files, link) {			\
128 		if (next_file_id == lftmp->id) {			\
129 			next_file_id++;					\
130 			goto retry;					\
131 		}							\
132 	}								\
133 	(a) = next_file_id;						\
134 } while(0)
135 
136 
137 /* XXX wrong name; we're looking at version provision tags here, not modules */
138 typedef TAILQ_HEAD(, modlist) modlisthead_t;
139 struct modlist {
140 	TAILQ_ENTRY(modlist) link;	/* chain together all modules */
141 	linker_file_t   container;
142 	const char 	*name;
143 	int             version;
144 };
145 typedef struct modlist *modlist_t;
146 static modlisthead_t found_modules;
147 
148 static int	linker_file_add_dependency(linker_file_t file,
149 		    linker_file_t dep);
150 static caddr_t	linker_file_lookup_symbol_internal(linker_file_t file,
151 		    const char* name, int deps);
152 static int	linker_load_module(const char *kldname,
153 		    const char *modname, struct linker_file *parent,
154 		    const struct mod_depend *verinfo, struct linker_file **lfpp);
155 static modlist_t modlist_lookup2(const char *name, const struct mod_depend *verinfo);
156 
157 static void
158 linker_init(void *arg)
159 {
160 
161 	sx_init(&kld_sx, "kernel linker");
162 	TAILQ_INIT(&classes);
163 	TAILQ_INIT(&linker_files);
164 }
165 
166 SYSINIT(linker, SI_SUB_KLD, SI_ORDER_FIRST, linker_init, NULL);
167 
168 static void
169 linker_stop_class_add(void *arg)
170 {
171 
172 	linker_no_more_classes = 1;
173 }
174 
175 SYSINIT(linker_class, SI_SUB_KLD, SI_ORDER_ANY, linker_stop_class_add, NULL);
176 
177 int
178 linker_add_class(linker_class_t lc)
179 {
180 
181 	/*
182 	 * We disallow any class registration past SI_ORDER_ANY
183 	 * of SI_SUB_KLD.  We bump the reference count to keep the
184 	 * ops from being freed.
185 	 */
186 	if (linker_no_more_classes == 1)
187 		return (EPERM);
188 	kobj_class_compile((kobj_class_t) lc);
189 	((kobj_class_t)lc)->refs++;	/* XXX: kobj_mtx */
190 	TAILQ_INSERT_TAIL(&classes, lc, link);
191 	return (0);
192 }
193 
194 static void
195 linker_file_sysinit(linker_file_t lf)
196 {
197 	struct sysinit **start, **stop, **sipp, **xipp, *save;
198 
199 	KLD_DPF(FILE, ("linker_file_sysinit: calling SYSINITs for %s\n",
200 	    lf->filename));
201 
202 	sx_assert(&kld_sx, SA_XLOCKED);
203 
204 	if (linker_file_lookup_set(lf, "sysinit_set", &start, &stop, NULL) != 0)
205 		return;
206 	/*
207 	 * Perform a bubble sort of the system initialization objects by
208 	 * their subsystem (primary key) and order (secondary key).
209 	 *
210 	 * Since some things care about execution order, this is the operation
211 	 * which ensures continued function.
212 	 */
213 	for (sipp = start; sipp < stop; sipp++) {
214 		for (xipp = sipp + 1; xipp < stop; xipp++) {
215 			if ((*sipp)->subsystem < (*xipp)->subsystem ||
216 			    ((*sipp)->subsystem == (*xipp)->subsystem &&
217 			    (*sipp)->order <= (*xipp)->order))
218 				continue;	/* skip */
219 			save = *sipp;
220 			*sipp = *xipp;
221 			*xipp = save;
222 		}
223 	}
224 
225 	/*
226 	 * Traverse the (now) ordered list of system initialization tasks.
227 	 * Perform each task, and continue on to the next task.
228 	 */
229 	sx_xunlock(&kld_sx);
230 	mtx_lock(&Giant);
231 	for (sipp = start; sipp < stop; sipp++) {
232 		if ((*sipp)->subsystem == SI_SUB_DUMMY)
233 			continue;	/* skip dummy task(s) */
234 
235 		/* Call function */
236 		(*((*sipp)->func)) ((*sipp)->udata);
237 	}
238 	mtx_unlock(&Giant);
239 	sx_xlock(&kld_sx);
240 }
241 
242 static void
243 linker_file_sysuninit(linker_file_t lf)
244 {
245 	struct sysinit **start, **stop, **sipp, **xipp, *save;
246 
247 	KLD_DPF(FILE, ("linker_file_sysuninit: calling SYSUNINITs for %s\n",
248 	    lf->filename));
249 
250 	sx_assert(&kld_sx, SA_XLOCKED);
251 
252 	if (linker_file_lookup_set(lf, "sysuninit_set", &start, &stop,
253 	    NULL) != 0)
254 		return;
255 
256 	/*
257 	 * Perform a reverse bubble sort of the system initialization objects
258 	 * by their subsystem (primary key) and order (secondary key).
259 	 *
260 	 * Since some things care about execution order, this is the operation
261 	 * which ensures continued function.
262 	 */
263 	for (sipp = start; sipp < stop; sipp++) {
264 		for (xipp = sipp + 1; xipp < stop; xipp++) {
265 			if ((*sipp)->subsystem > (*xipp)->subsystem ||
266 			    ((*sipp)->subsystem == (*xipp)->subsystem &&
267 			    (*sipp)->order >= (*xipp)->order))
268 				continue;	/* skip */
269 			save = *sipp;
270 			*sipp = *xipp;
271 			*xipp = save;
272 		}
273 	}
274 
275 	/*
276 	 * Traverse the (now) ordered list of system initialization tasks.
277 	 * Perform each task, and continue on to the next task.
278 	 */
279 	sx_xunlock(&kld_sx);
280 	mtx_lock(&Giant);
281 	for (sipp = start; sipp < stop; sipp++) {
282 		if ((*sipp)->subsystem == SI_SUB_DUMMY)
283 			continue;	/* skip dummy task(s) */
284 
285 		/* Call function */
286 		(*((*sipp)->func)) ((*sipp)->udata);
287 	}
288 	mtx_unlock(&Giant);
289 	sx_xlock(&kld_sx);
290 }
291 
292 static void
293 linker_file_register_sysctls(linker_file_t lf, bool enable)
294 {
295 	struct sysctl_oid **start, **stop, **oidp;
296 
297 	KLD_DPF(FILE,
298 	    ("linker_file_register_sysctls: registering SYSCTLs for %s\n",
299 	    lf->filename));
300 
301 	sx_assert(&kld_sx, SA_XLOCKED);
302 
303 	if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
304 		return;
305 
306 	sx_xunlock(&kld_sx);
307 	sysctl_wlock();
308 	for (oidp = start; oidp < stop; oidp++) {
309 		if (enable)
310 			sysctl_register_oid(*oidp);
311 		else
312 			sysctl_register_disabled_oid(*oidp);
313 	}
314 	sysctl_wunlock();
315 	sx_xlock(&kld_sx);
316 }
317 
318 static void
319 linker_file_enable_sysctls(linker_file_t lf)
320 {
321 	struct sysctl_oid **start, **stop, **oidp;
322 
323 	KLD_DPF(FILE,
324 	    ("linker_file_enable_sysctls: enable SYSCTLs for %s\n",
325 	    lf->filename));
326 
327 	sx_assert(&kld_sx, SA_XLOCKED);
328 
329 	if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
330 		return;
331 
332 	sx_xunlock(&kld_sx);
333 	sysctl_wlock();
334 	for (oidp = start; oidp < stop; oidp++)
335 		sysctl_enable_oid(*oidp);
336 	sysctl_wunlock();
337 	sx_xlock(&kld_sx);
338 }
339 
340 static void
341 linker_file_unregister_sysctls(linker_file_t lf)
342 {
343 	struct sysctl_oid **start, **stop, **oidp;
344 
345 	KLD_DPF(FILE, ("linker_file_unregister_sysctls: unregistering SYSCTLs"
346 	    " for %s\n", lf->filename));
347 
348 	sx_assert(&kld_sx, SA_XLOCKED);
349 
350 	if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
351 		return;
352 
353 	sx_xunlock(&kld_sx);
354 	sysctl_wlock();
355 	for (oidp = start; oidp < stop; oidp++)
356 		sysctl_unregister_oid(*oidp);
357 	sysctl_wunlock();
358 	sx_xlock(&kld_sx);
359 }
360 
361 static int
362 linker_file_register_modules(linker_file_t lf)
363 {
364 	struct mod_metadata **start, **stop, **mdp;
365 	const moduledata_t *moddata;
366 	int first_error, error;
367 
368 	KLD_DPF(FILE, ("linker_file_register_modules: registering modules"
369 	    " in %s\n", lf->filename));
370 
371 	sx_assert(&kld_sx, SA_XLOCKED);
372 
373 	if (linker_file_lookup_set(lf, "modmetadata_set", &start,
374 	    &stop, NULL) != 0) {
375 		/*
376 		 * This fallback should be unnecessary, but if we get booted
377 		 * from boot2 instead of loader and we are missing our
378 		 * metadata then we have to try the best we can.
379 		 */
380 		if (lf == linker_kernel_file) {
381 			start = SET_BEGIN(modmetadata_set);
382 			stop = SET_LIMIT(modmetadata_set);
383 		} else
384 			return (0);
385 	}
386 	first_error = 0;
387 	for (mdp = start; mdp < stop; mdp++) {
388 		if ((*mdp)->md_type != MDT_MODULE)
389 			continue;
390 		moddata = (*mdp)->md_data;
391 		KLD_DPF(FILE, ("Registering module %s in %s\n",
392 		    moddata->name, lf->filename));
393 		error = module_register(moddata, lf);
394 		if (error) {
395 			printf("Module %s failed to register: %d\n",
396 			    moddata->name, error);
397 			if (first_error == 0)
398 				first_error = error;
399 		}
400 	}
401 	return (first_error);
402 }
403 
404 static void
405 linker_init_kernel_modules(void)
406 {
407 
408 	sx_xlock(&kld_sx);
409 	linker_file_register_modules(linker_kernel_file);
410 	sx_xunlock(&kld_sx);
411 }
412 
413 SYSINIT(linker_kernel, SI_SUB_KLD, SI_ORDER_ANY, linker_init_kernel_modules,
414     NULL);
415 
416 static int
417 linker_load_file(const char *filename, linker_file_t *result)
418 {
419 	linker_class_t lc;
420 	linker_file_t lf;
421 	int foundfile, error, modules;
422 
423 	/* Refuse to load modules if securelevel raised */
424 	if (prison0.pr_securelevel > 0)
425 		return (EPERM);
426 
427 	sx_assert(&kld_sx, SA_XLOCKED);
428 	lf = linker_find_file_by_name(filename);
429 	if (lf) {
430 		KLD_DPF(FILE, ("linker_load_file: file %s is already loaded,"
431 		    " incrementing refs\n", filename));
432 		*result = lf;
433 		lf->refs++;
434 		return (0);
435 	}
436 	foundfile = 0;
437 	error = 0;
438 
439 	/*
440 	 * We do not need to protect (lock) classes here because there is
441 	 * no class registration past startup (SI_SUB_KLD, SI_ORDER_ANY)
442 	 * and there is no class deregistration mechanism at this time.
443 	 */
444 	TAILQ_FOREACH(lc, &classes, link) {
445 		KLD_DPF(FILE, ("linker_load_file: trying to load %s\n",
446 		    filename));
447 		error = LINKER_LOAD_FILE(lc, filename, &lf);
448 		/*
449 		 * If we got something other than ENOENT, then it exists but
450 		 * we cannot load it for some other reason.
451 		 */
452 		if (error != ENOENT)
453 			foundfile = 1;
454 		if (lf) {
455 			error = linker_file_register_modules(lf);
456 			if (error == EEXIST) {
457 				linker_file_unload(lf, LINKER_UNLOAD_FORCE);
458 				return (error);
459 			}
460 			modules = !TAILQ_EMPTY(&lf->modules);
461 			linker_file_register_sysctls(lf, false);
462 			linker_file_sysinit(lf);
463 			lf->flags |= LINKER_FILE_LINKED;
464 
465 			/*
466 			 * If all of the modules in this file failed
467 			 * to load, unload the file and return an
468 			 * error of ENOEXEC.
469 			 */
470 			if (modules && TAILQ_EMPTY(&lf->modules)) {
471 				linker_file_unload(lf, LINKER_UNLOAD_FORCE);
472 				return (ENOEXEC);
473 			}
474 			linker_file_enable_sysctls(lf);
475 			EVENTHANDLER_INVOKE(kld_load, lf);
476 			*result = lf;
477 			return (0);
478 		}
479 	}
480 	/*
481 	 * Less than ideal, but tells the user whether it failed to load or
482 	 * the module was not found.
483 	 */
484 	if (foundfile) {
485 
486 		/*
487 		 * If the file type has not been recognized by the last try
488 		 * printout a message before to fail.
489 		 */
490 		if (error == ENOSYS)
491 			printf("%s: %s - unsupported file type\n",
492 			    __func__, filename);
493 
494 		/*
495 		 * Format not recognized or otherwise unloadable.
496 		 * When loading a module that is statically built into
497 		 * the kernel EEXIST percolates back up as the return
498 		 * value.  Preserve this so that apps like sysinstall
499 		 * can recognize this special case and not post bogus
500 		 * dialog boxes.
501 		 */
502 		if (error != EEXIST)
503 			error = ENOEXEC;
504 	} else
505 		error = ENOENT;		/* Nothing found */
506 	return (error);
507 }
508 
509 int
510 linker_reference_module(const char *modname, struct mod_depend *verinfo,
511     linker_file_t *result)
512 {
513 	modlist_t mod;
514 	int error;
515 
516 	sx_xlock(&kld_sx);
517 	if ((mod = modlist_lookup2(modname, verinfo)) != NULL) {
518 		*result = mod->container;
519 		(*result)->refs++;
520 		sx_xunlock(&kld_sx);
521 		return (0);
522 	}
523 
524 	error = linker_load_module(NULL, modname, NULL, verinfo, result);
525 	sx_xunlock(&kld_sx);
526 	return (error);
527 }
528 
529 int
530 linker_release_module(const char *modname, struct mod_depend *verinfo,
531     linker_file_t lf)
532 {
533 	modlist_t mod;
534 	int error;
535 
536 	sx_xlock(&kld_sx);
537 	if (lf == NULL) {
538 		KASSERT(modname != NULL,
539 		    ("linker_release_module: no file or name"));
540 		mod = modlist_lookup2(modname, verinfo);
541 		if (mod == NULL) {
542 			sx_xunlock(&kld_sx);
543 			return (ESRCH);
544 		}
545 		lf = mod->container;
546 	} else
547 		KASSERT(modname == NULL && verinfo == NULL,
548 		    ("linker_release_module: both file and name"));
549 	error =	linker_file_unload(lf, LINKER_UNLOAD_NORMAL);
550 	sx_xunlock(&kld_sx);
551 	return (error);
552 }
553 
554 static linker_file_t
555 linker_find_file_by_name(const char *filename)
556 {
557 	linker_file_t lf;
558 	char *koname;
559 
560 	koname = malloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
561 	sprintf(koname, "%s.ko", filename);
562 
563 	sx_assert(&kld_sx, SA_XLOCKED);
564 	TAILQ_FOREACH(lf, &linker_files, link) {
565 		if (strcmp(lf->filename, koname) == 0)
566 			break;
567 		if (strcmp(lf->filename, filename) == 0)
568 			break;
569 	}
570 	free(koname, M_LINKER);
571 	return (lf);
572 }
573 
574 static linker_file_t
575 linker_find_file_by_id(int fileid)
576 {
577 	linker_file_t lf;
578 
579 	sx_assert(&kld_sx, SA_XLOCKED);
580 	TAILQ_FOREACH(lf, &linker_files, link)
581 		if (lf->id == fileid && lf->flags & LINKER_FILE_LINKED)
582 			break;
583 	return (lf);
584 }
585 
586 int
587 linker_file_foreach(linker_predicate_t *predicate, void *context)
588 {
589 	linker_file_t lf;
590 	int retval = 0;
591 
592 	sx_xlock(&kld_sx);
593 	TAILQ_FOREACH(lf, &linker_files, link) {
594 		retval = predicate(lf, context);
595 		if (retval != 0)
596 			break;
597 	}
598 	sx_xunlock(&kld_sx);
599 	return (retval);
600 }
601 
602 linker_file_t
603 linker_make_file(const char *pathname, linker_class_t lc)
604 {
605 	linker_file_t lf;
606 	const char *filename;
607 
608 	if (!cold)
609 		sx_assert(&kld_sx, SA_XLOCKED);
610 	filename = linker_basename(pathname);
611 
612 	KLD_DPF(FILE, ("linker_make_file: new file, filename='%s' for pathname='%s'\n", filename, pathname));
613 	lf = (linker_file_t)kobj_create((kobj_class_t)lc, M_LINKER, M_WAITOK);
614 	if (lf == NULL)
615 		return (NULL);
616 	lf->ctors_addr = 0;
617 	lf->ctors_size = 0;
618 	lf->refs = 1;
619 	lf->userrefs = 0;
620 	lf->flags = 0;
621 	lf->filename = strdup(filename, M_LINKER);
622 	lf->pathname = strdup(pathname, M_LINKER);
623 	LINKER_GET_NEXT_FILE_ID(lf->id);
624 	lf->ndeps = 0;
625 	lf->deps = NULL;
626 	lf->loadcnt = ++loadcnt;
627 #ifdef __arm__
628 	lf->exidx_addr = 0;
629 	lf->exidx_size = 0;
630 #endif
631 	STAILQ_INIT(&lf->common);
632 	TAILQ_INIT(&lf->modules);
633 	TAILQ_INSERT_TAIL(&linker_files, lf, link);
634 	return (lf);
635 }
636 
637 int
638 linker_file_unload(linker_file_t file, int flags)
639 {
640 	module_t mod, next;
641 	modlist_t ml, nextml;
642 	struct common_symbol *cp;
643 	int error, i;
644 
645 	/* Refuse to unload modules if securelevel raised. */
646 	if (prison0.pr_securelevel > 0)
647 		return (EPERM);
648 
649 	sx_assert(&kld_sx, SA_XLOCKED);
650 	KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
651 
652 	/* Easy case of just dropping a reference. */
653 	if (file->refs > 1) {
654 		file->refs--;
655 		return (0);
656 	}
657 
658 	/* Give eventhandlers a chance to prevent the unload. */
659 	error = 0;
660 	EVENTHANDLER_INVOKE(kld_unload_try, file, &error);
661 	if (error != 0)
662 		return (EBUSY);
663 
664 	KLD_DPF(FILE, ("linker_file_unload: file is unloading,"
665 	    " informing modules\n"));
666 
667 	/*
668 	 * Quiesce all the modules to give them a chance to veto the unload.
669 	 */
670 	MOD_SLOCK;
671 	for (mod = TAILQ_FIRST(&file->modules); mod;
672 	     mod = module_getfnext(mod)) {
673 
674 		error = module_quiesce(mod);
675 		if (error != 0 && flags != LINKER_UNLOAD_FORCE) {
676 			KLD_DPF(FILE, ("linker_file_unload: module %s"
677 			    " vetoed unload\n", module_getname(mod)));
678 			/*
679 			 * XXX: Do we need to tell all the quiesced modules
680 			 * that they can resume work now via a new module
681 			 * event?
682 			 */
683 			MOD_SUNLOCK;
684 			return (error);
685 		}
686 	}
687 	MOD_SUNLOCK;
688 
689 	/*
690 	 * Inform any modules associated with this file that they are
691 	 * being unloaded.
692 	 */
693 	MOD_XLOCK;
694 	for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
695 		next = module_getfnext(mod);
696 		MOD_XUNLOCK;
697 
698 		/*
699 		 * Give the module a chance to veto the unload.
700 		 */
701 		if ((error = module_unload(mod)) != 0) {
702 #ifdef KLD_DEBUG
703 			MOD_SLOCK;
704 			KLD_DPF(FILE, ("linker_file_unload: module %s"
705 			    " failed unload\n", module_getname(mod)));
706 			MOD_SUNLOCK;
707 #endif
708 			return (error);
709 		}
710 		MOD_XLOCK;
711 		module_release(mod);
712 	}
713 	MOD_XUNLOCK;
714 
715 	TAILQ_FOREACH_SAFE(ml, &found_modules, link, nextml) {
716 		if (ml->container == file) {
717 			TAILQ_REMOVE(&found_modules, ml, link);
718 			free(ml, M_LINKER);
719 		}
720 	}
721 
722 	/*
723 	 * Don't try to run SYSUNINITs if we are unloaded due to a
724 	 * link error.
725 	 */
726 	if (file->flags & LINKER_FILE_LINKED) {
727 		file->flags &= ~LINKER_FILE_LINKED;
728 		linker_file_unregister_sysctls(file);
729 		linker_file_sysuninit(file);
730 	}
731 	TAILQ_REMOVE(&linker_files, file, link);
732 
733 	if (file->deps) {
734 		for (i = 0; i < file->ndeps; i++)
735 			linker_file_unload(file->deps[i], flags);
736 		free(file->deps, M_LINKER);
737 		file->deps = NULL;
738 	}
739 	while ((cp = STAILQ_FIRST(&file->common)) != NULL) {
740 		STAILQ_REMOVE_HEAD(&file->common, link);
741 		free(cp, M_LINKER);
742 	}
743 
744 	LINKER_UNLOAD(file);
745 
746 	EVENTHANDLER_INVOKE(kld_unload, file->filename, file->address,
747 	    file->size);
748 
749 	if (file->filename) {
750 		free(file->filename, M_LINKER);
751 		file->filename = NULL;
752 	}
753 	if (file->pathname) {
754 		free(file->pathname, M_LINKER);
755 		file->pathname = NULL;
756 	}
757 	kobj_delete((kobj_t) file, M_LINKER);
758 	return (0);
759 }
760 
761 int
762 linker_ctf_get(linker_file_t file, linker_ctf_t *lc)
763 {
764 	return (LINKER_CTF_GET(file, lc));
765 }
766 
767 static int
768 linker_file_add_dependency(linker_file_t file, linker_file_t dep)
769 {
770 	linker_file_t *newdeps;
771 
772 	sx_assert(&kld_sx, SA_XLOCKED);
773 	file->deps = realloc(file->deps, (file->ndeps + 1) * sizeof(*newdeps),
774 	    M_LINKER, M_WAITOK | M_ZERO);
775 	file->deps[file->ndeps] = dep;
776 	file->ndeps++;
777 	KLD_DPF(FILE, ("linker_file_add_dependency:"
778 	    " adding %s as dependency for %s\n",
779 	    dep->filename, file->filename));
780 	return (0);
781 }
782 
783 /*
784  * Locate a linker set and its contents.  This is a helper function to avoid
785  * linker_if.h exposure elsewhere.  Note: firstp and lastp are really void **.
786  * This function is used in this file so we can avoid having lots of (void **)
787  * casts.
788  */
789 int
790 linker_file_lookup_set(linker_file_t file, const char *name,
791     void *firstp, void *lastp, int *countp)
792 {
793 
794 	sx_assert(&kld_sx, SA_LOCKED);
795 	return (LINKER_LOOKUP_SET(file, name, firstp, lastp, countp));
796 }
797 
798 /*
799  * List all functions in a file.
800  */
801 int
802 linker_file_function_listall(linker_file_t lf,
803     linker_function_nameval_callback_t callback_func, void *arg)
804 {
805 	return (LINKER_EACH_FUNCTION_NAMEVAL(lf, callback_func, arg));
806 }
807 
808 caddr_t
809 linker_file_lookup_symbol(linker_file_t file, const char *name, int deps)
810 {
811 	caddr_t sym;
812 	int locked;
813 
814 	locked = sx_xlocked(&kld_sx);
815 	if (!locked)
816 		sx_xlock(&kld_sx);
817 	sym = linker_file_lookup_symbol_internal(file, name, deps);
818 	if (!locked)
819 		sx_xunlock(&kld_sx);
820 	return (sym);
821 }
822 
823 static caddr_t
824 linker_file_lookup_symbol_internal(linker_file_t file, const char *name,
825     int deps)
826 {
827 	c_linker_sym_t sym;
828 	linker_symval_t symval;
829 	caddr_t address;
830 	size_t common_size = 0;
831 	int i;
832 
833 	sx_assert(&kld_sx, SA_XLOCKED);
834 	KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n",
835 	    file, name, deps));
836 
837 	if (LINKER_LOOKUP_SYMBOL(file, name, &sym) == 0) {
838 		LINKER_SYMBOL_VALUES(file, sym, &symval);
839 		if (symval.value == 0)
840 			/*
841 			 * For commons, first look them up in the
842 			 * dependencies and only allocate space if not found
843 			 * there.
844 			 */
845 			common_size = symval.size;
846 		else {
847 			KLD_DPF(SYM, ("linker_file_lookup_symbol: symbol"
848 			    ".value=%p\n", symval.value));
849 			return (symval.value);
850 		}
851 	}
852 	if (deps) {
853 		for (i = 0; i < file->ndeps; i++) {
854 			address = linker_file_lookup_symbol_internal(
855 			    file->deps[i], name, 0);
856 			if (address) {
857 				KLD_DPF(SYM, ("linker_file_lookup_symbol:"
858 				    " deps value=%p\n", address));
859 				return (address);
860 			}
861 		}
862 	}
863 	if (common_size > 0) {
864 		/*
865 		 * This is a common symbol which was not found in the
866 		 * dependencies.  We maintain a simple common symbol table in
867 		 * the file object.
868 		 */
869 		struct common_symbol *cp;
870 
871 		STAILQ_FOREACH(cp, &file->common, link) {
872 			if (strcmp(cp->name, name) == 0) {
873 				KLD_DPF(SYM, ("linker_file_lookup_symbol:"
874 				    " old common value=%p\n", cp->address));
875 				return (cp->address);
876 			}
877 		}
878 		/*
879 		 * Round the symbol size up to align.
880 		 */
881 		common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
882 		cp = malloc(sizeof(struct common_symbol)
883 		    + common_size + strlen(name) + 1, M_LINKER,
884 		    M_WAITOK | M_ZERO);
885 		cp->address = (caddr_t)(cp + 1);
886 		cp->name = cp->address + common_size;
887 		strcpy(cp->name, name);
888 		bzero(cp->address, common_size);
889 		STAILQ_INSERT_TAIL(&file->common, cp, link);
890 
891 		KLD_DPF(SYM, ("linker_file_lookup_symbol: new common"
892 		    " value=%p\n", cp->address));
893 		return (cp->address);
894 	}
895 	KLD_DPF(SYM, ("linker_file_lookup_symbol: fail\n"));
896 	return (0);
897 }
898 
899 /*
900  * Both DDB and stack(9) rely on the kernel linker to provide forward and
901  * backward lookup of symbols.  However, DDB and sometimes stack(9) need to
902  * do this in a lockfree manner.  We provide a set of internal helper
903  * routines to perform these operations without locks, and then wrappers that
904  * optionally lock.
905  *
906  * linker_debug_lookup() is ifdef DDB as currently it's only used by DDB.
907  */
908 #ifdef DDB
909 static int
910 linker_debug_lookup(const char *symstr, c_linker_sym_t *sym)
911 {
912 	linker_file_t lf;
913 
914 	TAILQ_FOREACH(lf, &linker_files, link) {
915 		if (LINKER_LOOKUP_SYMBOL(lf, symstr, sym) == 0)
916 			return (0);
917 	}
918 	return (ENOENT);
919 }
920 #endif
921 
922 static int
923 linker_debug_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
924 {
925 	linker_file_t lf;
926 	c_linker_sym_t best, es;
927 	u_long diff, bestdiff, off;
928 
929 	best = 0;
930 	off = (uintptr_t)value;
931 	bestdiff = off;
932 	TAILQ_FOREACH(lf, &linker_files, link) {
933 		if (LINKER_SEARCH_SYMBOL(lf, value, &es, &diff) != 0)
934 			continue;
935 		if (es != 0 && diff < bestdiff) {
936 			best = es;
937 			bestdiff = diff;
938 		}
939 		if (bestdiff == 0)
940 			break;
941 	}
942 	if (best) {
943 		*sym = best;
944 		*diffp = bestdiff;
945 		return (0);
946 	} else {
947 		*sym = 0;
948 		*diffp = off;
949 		return (ENOENT);
950 	}
951 }
952 
953 static int
954 linker_debug_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
955 {
956 	linker_file_t lf;
957 
958 	TAILQ_FOREACH(lf, &linker_files, link) {
959 		if (LINKER_SYMBOL_VALUES(lf, sym, symval) == 0)
960 			return (0);
961 	}
962 	return (ENOENT);
963 }
964 
965 static int
966 linker_debug_search_symbol_name(caddr_t value, char *buf, u_int buflen,
967     long *offset)
968 {
969 	linker_symval_t symval;
970 	c_linker_sym_t sym;
971 	int error;
972 
973 	*offset = 0;
974 	error = linker_debug_search_symbol(value, &sym, offset);
975 	if (error)
976 		return (error);
977 	error = linker_debug_symbol_values(sym, &symval);
978 	if (error)
979 		return (error);
980 	strlcpy(buf, symval.name, buflen);
981 	return (0);
982 }
983 
984 /*
985  * DDB Helpers.  DDB has to look across multiple files with their own symbol
986  * tables and string tables.
987  *
988  * Note that we do not obey list locking protocols here.  We really don't need
989  * DDB to hang because somebody's got the lock held.  We'll take the chance
990  * that the files list is inconsistent instead.
991  */
992 #ifdef DDB
993 int
994 linker_ddb_lookup(const char *symstr, c_linker_sym_t *sym)
995 {
996 
997 	return (linker_debug_lookup(symstr, sym));
998 }
999 #endif
1000 
1001 int
1002 linker_ddb_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
1003 {
1004 
1005 	return (linker_debug_search_symbol(value, sym, diffp));
1006 }
1007 
1008 int
1009 linker_ddb_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
1010 {
1011 
1012 	return (linker_debug_symbol_values(sym, symval));
1013 }
1014 
1015 int
1016 linker_ddb_search_symbol_name(caddr_t value, char *buf, u_int buflen,
1017     long *offset)
1018 {
1019 
1020 	return (linker_debug_search_symbol_name(value, buf, buflen, offset));
1021 }
1022 
1023 /*
1024  * stack(9) helper for non-debugging environemnts.  Unlike DDB helpers, we do
1025  * obey locking protocols, and offer a significantly less complex interface.
1026  */
1027 int
1028 linker_search_symbol_name_flags(caddr_t value, char *buf, u_int buflen,
1029     long *offset, int flags)
1030 {
1031 	int error;
1032 
1033 	KASSERT((flags & (M_NOWAIT | M_WAITOK)) != 0 &&
1034 	    (flags & (M_NOWAIT | M_WAITOK)) != (M_NOWAIT | M_WAITOK),
1035 	    ("%s: bad flags: 0x%x", __func__, flags));
1036 
1037 	if (flags & M_NOWAIT) {
1038 		if (!sx_try_slock(&kld_sx))
1039 			return (EWOULDBLOCK);
1040 	} else
1041 		sx_slock(&kld_sx);
1042 
1043 	error = linker_debug_search_symbol_name(value, buf, buflen, offset);
1044 	sx_sunlock(&kld_sx);
1045 	return (error);
1046 }
1047 
1048 int
1049 linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
1050     long *offset)
1051 {
1052 
1053 	return (linker_search_symbol_name_flags(value, buf, buflen, offset,
1054 	    M_WAITOK));
1055 }
1056 
1057 /*
1058  * Syscalls.
1059  */
1060 int
1061 kern_kldload(struct thread *td, const char *file, int *fileid)
1062 {
1063 	const char *kldname, *modname;
1064 	linker_file_t lf;
1065 	int error;
1066 
1067 	if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
1068 		return (error);
1069 
1070 	if ((error = priv_check(td, PRIV_KLD_LOAD)) != 0)
1071 		return (error);
1072 
1073 	/*
1074 	 * It is possible that kldloaded module will attach a new ifnet,
1075 	 * so vnet context must be set when this ocurs.
1076 	 */
1077 	CURVNET_SET(TD_TO_VNET(td));
1078 
1079 	/*
1080 	 * If file does not contain a qualified name or any dot in it
1081 	 * (kldname.ko, or kldname.ver.ko) treat it as an interface
1082 	 * name.
1083 	 */
1084 	if (strchr(file, '/') || strchr(file, '.')) {
1085 		kldname = file;
1086 		modname = NULL;
1087 	} else {
1088 		kldname = NULL;
1089 		modname = file;
1090 	}
1091 
1092 	sx_xlock(&kld_sx);
1093 	error = linker_load_module(kldname, modname, NULL, NULL, &lf);
1094 	if (error) {
1095 		sx_xunlock(&kld_sx);
1096 		goto done;
1097 	}
1098 	lf->userrefs++;
1099 	if (fileid != NULL)
1100 		*fileid = lf->id;
1101 	sx_xunlock(&kld_sx);
1102 
1103 done:
1104 	CURVNET_RESTORE();
1105 	return (error);
1106 }
1107 
1108 int
1109 sys_kldload(struct thread *td, struct kldload_args *uap)
1110 {
1111 	char *pathname = NULL;
1112 	int error, fileid;
1113 
1114 	td->td_retval[0] = -1;
1115 
1116 	pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1117 	error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL);
1118 	if (error == 0) {
1119 		error = kern_kldload(td, pathname, &fileid);
1120 		if (error == 0)
1121 			td->td_retval[0] = fileid;
1122 	}
1123 	free(pathname, M_TEMP);
1124 	return (error);
1125 }
1126 
1127 int
1128 kern_kldunload(struct thread *td, int fileid, int flags)
1129 {
1130 	linker_file_t lf;
1131 	int error = 0;
1132 
1133 	if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
1134 		return (error);
1135 
1136 	if ((error = priv_check(td, PRIV_KLD_UNLOAD)) != 0)
1137 		return (error);
1138 
1139 	CURVNET_SET(TD_TO_VNET(td));
1140 	sx_xlock(&kld_sx);
1141 	lf = linker_find_file_by_id(fileid);
1142 	if (lf) {
1143 		KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
1144 
1145 		if (lf->userrefs == 0) {
1146 			/*
1147 			 * XXX: maybe LINKER_UNLOAD_FORCE should override ?
1148 			 */
1149 			printf("kldunload: attempt to unload file that was"
1150 			    " loaded by the kernel\n");
1151 			error = EBUSY;
1152 		} else {
1153 			lf->userrefs--;
1154 			error = linker_file_unload(lf, flags);
1155 			if (error)
1156 				lf->userrefs++;
1157 		}
1158 	} else
1159 		error = ENOENT;
1160 	sx_xunlock(&kld_sx);
1161 
1162 	CURVNET_RESTORE();
1163 	return (error);
1164 }
1165 
1166 int
1167 sys_kldunload(struct thread *td, struct kldunload_args *uap)
1168 {
1169 
1170 	return (kern_kldunload(td, uap->fileid, LINKER_UNLOAD_NORMAL));
1171 }
1172 
1173 int
1174 sys_kldunloadf(struct thread *td, struct kldunloadf_args *uap)
1175 {
1176 
1177 	if (uap->flags != LINKER_UNLOAD_NORMAL &&
1178 	    uap->flags != LINKER_UNLOAD_FORCE)
1179 		return (EINVAL);
1180 	return (kern_kldunload(td, uap->fileid, uap->flags));
1181 }
1182 
1183 int
1184 sys_kldfind(struct thread *td, struct kldfind_args *uap)
1185 {
1186 	char *pathname;
1187 	const char *filename;
1188 	linker_file_t lf;
1189 	int error;
1190 
1191 #ifdef MAC
1192 	error = mac_kld_check_stat(td->td_ucred);
1193 	if (error)
1194 		return (error);
1195 #endif
1196 
1197 	td->td_retval[0] = -1;
1198 
1199 	pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1200 	if ((error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL)) != 0)
1201 		goto out;
1202 
1203 	filename = linker_basename(pathname);
1204 	sx_xlock(&kld_sx);
1205 	lf = linker_find_file_by_name(filename);
1206 	if (lf)
1207 		td->td_retval[0] = lf->id;
1208 	else
1209 		error = ENOENT;
1210 	sx_xunlock(&kld_sx);
1211 out:
1212 	free(pathname, M_TEMP);
1213 	return (error);
1214 }
1215 
1216 int
1217 sys_kldnext(struct thread *td, struct kldnext_args *uap)
1218 {
1219 	linker_file_t lf;
1220 	int error = 0;
1221 
1222 #ifdef MAC
1223 	error = mac_kld_check_stat(td->td_ucred);
1224 	if (error)
1225 		return (error);
1226 #endif
1227 
1228 	sx_xlock(&kld_sx);
1229 	if (uap->fileid == 0)
1230 		lf = TAILQ_FIRST(&linker_files);
1231 	else {
1232 		lf = linker_find_file_by_id(uap->fileid);
1233 		if (lf == NULL) {
1234 			error = ENOENT;
1235 			goto out;
1236 		}
1237 		lf = TAILQ_NEXT(lf, link);
1238 	}
1239 
1240 	/* Skip partially loaded files. */
1241 	while (lf != NULL && !(lf->flags & LINKER_FILE_LINKED))
1242 		lf = TAILQ_NEXT(lf, link);
1243 
1244 	if (lf)
1245 		td->td_retval[0] = lf->id;
1246 	else
1247 		td->td_retval[0] = 0;
1248 out:
1249 	sx_xunlock(&kld_sx);
1250 	return (error);
1251 }
1252 
1253 int
1254 sys_kldstat(struct thread *td, struct kldstat_args *uap)
1255 {
1256 	struct kld_file_stat *stat;
1257 	int error, version;
1258 
1259 	/*
1260 	 * Check the version of the user's structure.
1261 	 */
1262 	if ((error = copyin(&uap->stat->version, &version, sizeof(version)))
1263 	    != 0)
1264 		return (error);
1265 	if (version != sizeof(struct kld_file_stat_1) &&
1266 	    version != sizeof(struct kld_file_stat))
1267 		return (EINVAL);
1268 
1269 	stat = malloc(sizeof(*stat), M_TEMP, M_WAITOK | M_ZERO);
1270 	error = kern_kldstat(td, uap->fileid, stat);
1271 	if (error == 0)
1272 		error = copyout(stat, uap->stat, version);
1273 	free(stat, M_TEMP);
1274 	return (error);
1275 }
1276 
1277 int
1278 kern_kldstat(struct thread *td, int fileid, struct kld_file_stat *stat)
1279 {
1280 	linker_file_t lf;
1281 	int namelen;
1282 #ifdef MAC
1283 	int error;
1284 
1285 	error = mac_kld_check_stat(td->td_ucred);
1286 	if (error)
1287 		return (error);
1288 #endif
1289 
1290 	sx_xlock(&kld_sx);
1291 	lf = linker_find_file_by_id(fileid);
1292 	if (lf == NULL) {
1293 		sx_xunlock(&kld_sx);
1294 		return (ENOENT);
1295 	}
1296 
1297 	/* Version 1 fields: */
1298 	namelen = strlen(lf->filename) + 1;
1299 	if (namelen > sizeof(stat->name))
1300 		namelen = sizeof(stat->name);
1301 	bcopy(lf->filename, &stat->name[0], namelen);
1302 	stat->refs = lf->refs;
1303 	stat->id = lf->id;
1304 	stat->address = lf->address;
1305 	stat->size = lf->size;
1306 	/* Version 2 fields: */
1307 	namelen = strlen(lf->pathname) + 1;
1308 	if (namelen > sizeof(stat->pathname))
1309 		namelen = sizeof(stat->pathname);
1310 	bcopy(lf->pathname, &stat->pathname[0], namelen);
1311 	sx_xunlock(&kld_sx);
1312 
1313 	td->td_retval[0] = 0;
1314 	return (0);
1315 }
1316 
1317 #ifdef DDB
1318 DB_COMMAND(kldstat, db_kldstat)
1319 {
1320 	linker_file_t lf;
1321 
1322 #define	POINTER_WIDTH	((int)(sizeof(void *) * 2 + 2))
1323 	db_printf("Id Refs Address%*c Size     Name\n", POINTER_WIDTH - 7, ' ');
1324 #undef	POINTER_WIDTH
1325 	TAILQ_FOREACH(lf, &linker_files, link) {
1326 		if (db_pager_quit)
1327 			return;
1328 		db_printf("%2d %4d %p %-8zx %s\n", lf->id, lf->refs,
1329 		    lf->address, lf->size, lf->filename);
1330 	}
1331 }
1332 #endif /* DDB */
1333 
1334 int
1335 sys_kldfirstmod(struct thread *td, struct kldfirstmod_args *uap)
1336 {
1337 	linker_file_t lf;
1338 	module_t mp;
1339 	int error = 0;
1340 
1341 #ifdef MAC
1342 	error = mac_kld_check_stat(td->td_ucred);
1343 	if (error)
1344 		return (error);
1345 #endif
1346 
1347 	sx_xlock(&kld_sx);
1348 	lf = linker_find_file_by_id(uap->fileid);
1349 	if (lf) {
1350 		MOD_SLOCK;
1351 		mp = TAILQ_FIRST(&lf->modules);
1352 		if (mp != NULL)
1353 			td->td_retval[0] = module_getid(mp);
1354 		else
1355 			td->td_retval[0] = 0;
1356 		MOD_SUNLOCK;
1357 	} else
1358 		error = ENOENT;
1359 	sx_xunlock(&kld_sx);
1360 	return (error);
1361 }
1362 
1363 int
1364 sys_kldsym(struct thread *td, struct kldsym_args *uap)
1365 {
1366 	char *symstr = NULL;
1367 	c_linker_sym_t sym;
1368 	linker_symval_t symval;
1369 	linker_file_t lf;
1370 	struct kld_sym_lookup lookup;
1371 	int error = 0;
1372 
1373 #ifdef MAC
1374 	error = mac_kld_check_stat(td->td_ucred);
1375 	if (error)
1376 		return (error);
1377 #endif
1378 
1379 	if ((error = copyin(uap->data, &lookup, sizeof(lookup))) != 0)
1380 		return (error);
1381 	if (lookup.version != sizeof(lookup) ||
1382 	    uap->cmd != KLDSYM_LOOKUP)
1383 		return (EINVAL);
1384 	symstr = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1385 	if ((error = copyinstr(lookup.symname, symstr, MAXPATHLEN, NULL)) != 0)
1386 		goto out;
1387 	sx_xlock(&kld_sx);
1388 	if (uap->fileid != 0) {
1389 		lf = linker_find_file_by_id(uap->fileid);
1390 		if (lf == NULL)
1391 			error = ENOENT;
1392 		else if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
1393 		    LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
1394 			lookup.symvalue = (uintptr_t) symval.value;
1395 			lookup.symsize = symval.size;
1396 			error = copyout(&lookup, uap->data, sizeof(lookup));
1397 		} else
1398 			error = ENOENT;
1399 	} else {
1400 		TAILQ_FOREACH(lf, &linker_files, link) {
1401 			if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
1402 			    LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
1403 				lookup.symvalue = (uintptr_t)symval.value;
1404 				lookup.symsize = symval.size;
1405 				error = copyout(&lookup, uap->data,
1406 				    sizeof(lookup));
1407 				break;
1408 			}
1409 		}
1410 		if (lf == NULL)
1411 			error = ENOENT;
1412 	}
1413 	sx_xunlock(&kld_sx);
1414 out:
1415 	free(symstr, M_TEMP);
1416 	return (error);
1417 }
1418 
1419 /*
1420  * Preloaded module support
1421  */
1422 
1423 static modlist_t
1424 modlist_lookup(const char *name, int ver)
1425 {
1426 	modlist_t mod;
1427 
1428 	TAILQ_FOREACH(mod, &found_modules, link) {
1429 		if (strcmp(mod->name, name) == 0 &&
1430 		    (ver == 0 || mod->version == ver))
1431 			return (mod);
1432 	}
1433 	return (NULL);
1434 }
1435 
1436 static modlist_t
1437 modlist_lookup2(const char *name, const struct mod_depend *verinfo)
1438 {
1439 	modlist_t mod, bestmod;
1440 	int ver;
1441 
1442 	if (verinfo == NULL)
1443 		return (modlist_lookup(name, 0));
1444 	bestmod = NULL;
1445 	TAILQ_FOREACH(mod, &found_modules, link) {
1446 		if (strcmp(mod->name, name) != 0)
1447 			continue;
1448 		ver = mod->version;
1449 		if (ver == verinfo->md_ver_preferred)
1450 			return (mod);
1451 		if (ver >= verinfo->md_ver_minimum &&
1452 		    ver <= verinfo->md_ver_maximum &&
1453 		    (bestmod == NULL || ver > bestmod->version))
1454 			bestmod = mod;
1455 	}
1456 	return (bestmod);
1457 }
1458 
1459 static modlist_t
1460 modlist_newmodule(const char *modname, int version, linker_file_t container)
1461 {
1462 	modlist_t mod;
1463 
1464 	mod = malloc(sizeof(struct modlist), M_LINKER, M_NOWAIT | M_ZERO);
1465 	if (mod == NULL)
1466 		panic("no memory for module list");
1467 	mod->container = container;
1468 	mod->name = modname;
1469 	mod->version = version;
1470 	TAILQ_INSERT_TAIL(&found_modules, mod, link);
1471 	return (mod);
1472 }
1473 
1474 static void
1475 linker_addmodules(linker_file_t lf, struct mod_metadata **start,
1476     struct mod_metadata **stop, int preload)
1477 {
1478 	struct mod_metadata *mp, **mdp;
1479 	const char *modname;
1480 	int ver;
1481 
1482 	for (mdp = start; mdp < stop; mdp++) {
1483 		mp = *mdp;
1484 		if (mp->md_type != MDT_VERSION)
1485 			continue;
1486 		modname = mp->md_cval;
1487 		ver = ((const struct mod_version *)mp->md_data)->mv_version;
1488 		if (modlist_lookup(modname, ver) != NULL) {
1489 			printf("module %s already present!\n", modname);
1490 			/* XXX what can we do? this is a build error. :-( */
1491 			continue;
1492 		}
1493 		modlist_newmodule(modname, ver, lf);
1494 	}
1495 }
1496 
1497 static void
1498 linker_preload(void *arg)
1499 {
1500 	caddr_t modptr;
1501 	const char *modname, *nmodname;
1502 	char *modtype;
1503 	linker_file_t lf, nlf;
1504 	linker_class_t lc;
1505 	int error;
1506 	linker_file_list_t loaded_files;
1507 	linker_file_list_t depended_files;
1508 	struct mod_metadata *mp, *nmp;
1509 	struct mod_metadata **start, **stop, **mdp, **nmdp;
1510 	const struct mod_depend *verinfo;
1511 	int nver;
1512 	int resolves;
1513 	modlist_t mod;
1514 	struct sysinit **si_start, **si_stop;
1515 
1516 	TAILQ_INIT(&loaded_files);
1517 	TAILQ_INIT(&depended_files);
1518 	TAILQ_INIT(&found_modules);
1519 	error = 0;
1520 
1521 	modptr = NULL;
1522 	sx_xlock(&kld_sx);
1523 	while ((modptr = preload_search_next_name(modptr)) != NULL) {
1524 		modname = (char *)preload_search_info(modptr, MODINFO_NAME);
1525 		modtype = (char *)preload_search_info(modptr, MODINFO_TYPE);
1526 		if (modname == NULL) {
1527 			printf("Preloaded module at %p does not have a"
1528 			    " name!\n", modptr);
1529 			continue;
1530 		}
1531 		if (modtype == NULL) {
1532 			printf("Preloaded module at %p does not have a type!\n",
1533 			    modptr);
1534 			continue;
1535 		}
1536 		if (bootverbose)
1537 			printf("Preloaded %s \"%s\" at %p.\n", modtype, modname,
1538 			    modptr);
1539 		lf = NULL;
1540 		TAILQ_FOREACH(lc, &classes, link) {
1541 			error = LINKER_LINK_PRELOAD(lc, modname, &lf);
1542 			if (!error)
1543 				break;
1544 			lf = NULL;
1545 		}
1546 		if (lf)
1547 			TAILQ_INSERT_TAIL(&loaded_files, lf, loaded);
1548 	}
1549 
1550 	/*
1551 	 * First get a list of stuff in the kernel.
1552 	 */
1553 	if (linker_file_lookup_set(linker_kernel_file, MDT_SETNAME, &start,
1554 	    &stop, NULL) == 0)
1555 		linker_addmodules(linker_kernel_file, start, stop, 1);
1556 
1557 	/*
1558 	 * This is a once-off kinky bubble sort to resolve relocation
1559 	 * dependency requirements.
1560 	 */
1561 restart:
1562 	TAILQ_FOREACH(lf, &loaded_files, loaded) {
1563 		error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
1564 		    &stop, NULL);
1565 		/*
1566 		 * First, look to see if we would successfully link with this
1567 		 * stuff.
1568 		 */
1569 		resolves = 1;	/* unless we know otherwise */
1570 		if (!error) {
1571 			for (mdp = start; mdp < stop; mdp++) {
1572 				mp = *mdp;
1573 				if (mp->md_type != MDT_DEPEND)
1574 					continue;
1575 				modname = mp->md_cval;
1576 				verinfo = mp->md_data;
1577 				for (nmdp = start; nmdp < stop; nmdp++) {
1578 					nmp = *nmdp;
1579 					if (nmp->md_type != MDT_VERSION)
1580 						continue;
1581 					nmodname = nmp->md_cval;
1582 					if (strcmp(modname, nmodname) == 0)
1583 						break;
1584 				}
1585 				if (nmdp < stop)   /* it's a self reference */
1586 					continue;
1587 
1588 				/*
1589 				 * ok, the module isn't here yet, we
1590 				 * are not finished
1591 				 */
1592 				if (modlist_lookup2(modname, verinfo) == NULL)
1593 					resolves = 0;
1594 			}
1595 		}
1596 		/*
1597 		 * OK, if we found our modules, we can link.  So, "provide"
1598 		 * the modules inside and add it to the end of the link order
1599 		 * list.
1600 		 */
1601 		if (resolves) {
1602 			if (!error) {
1603 				for (mdp = start; mdp < stop; mdp++) {
1604 					mp = *mdp;
1605 					if (mp->md_type != MDT_VERSION)
1606 						continue;
1607 					modname = mp->md_cval;
1608 					nver = ((const struct mod_version *)
1609 					    mp->md_data)->mv_version;
1610 					if (modlist_lookup(modname,
1611 					    nver) != NULL) {
1612 						printf("module %s already"
1613 						    " present!\n", modname);
1614 						TAILQ_REMOVE(&loaded_files,
1615 						    lf, loaded);
1616 						linker_file_unload(lf,
1617 						    LINKER_UNLOAD_FORCE);
1618 						/* we changed tailq next ptr */
1619 						goto restart;
1620 					}
1621 					modlist_newmodule(modname, nver, lf);
1622 				}
1623 			}
1624 			TAILQ_REMOVE(&loaded_files, lf, loaded);
1625 			TAILQ_INSERT_TAIL(&depended_files, lf, loaded);
1626 			/*
1627 			 * Since we provided modules, we need to restart the
1628 			 * sort so that the previous files that depend on us
1629 			 * have a chance. Also, we've busted the tailq next
1630 			 * pointer with the REMOVE.
1631 			 */
1632 			goto restart;
1633 		}
1634 	}
1635 
1636 	/*
1637 	 * At this point, we check to see what could not be resolved..
1638 	 */
1639 	while ((lf = TAILQ_FIRST(&loaded_files)) != NULL) {
1640 		TAILQ_REMOVE(&loaded_files, lf, loaded);
1641 		printf("KLD file %s is missing dependencies\n", lf->filename);
1642 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1643 	}
1644 
1645 	/*
1646 	 * We made it. Finish off the linking in the order we determined.
1647 	 */
1648 	TAILQ_FOREACH_SAFE(lf, &depended_files, loaded, nlf) {
1649 		if (linker_kernel_file) {
1650 			linker_kernel_file->refs++;
1651 			error = linker_file_add_dependency(lf,
1652 			    linker_kernel_file);
1653 			if (error)
1654 				panic("cannot add dependency");
1655 		}
1656 		error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
1657 		    &stop, NULL);
1658 		if (!error) {
1659 			for (mdp = start; mdp < stop; mdp++) {
1660 				mp = *mdp;
1661 				if (mp->md_type != MDT_DEPEND)
1662 					continue;
1663 				modname = mp->md_cval;
1664 				verinfo = mp->md_data;
1665 				mod = modlist_lookup2(modname, verinfo);
1666 				if (mod == NULL) {
1667 					printf("KLD file %s - cannot find "
1668 					    "dependency \"%s\"\n",
1669 					    lf->filename, modname);
1670 					goto fail;
1671 				}
1672 				/* Don't count self-dependencies */
1673 				if (lf == mod->container)
1674 					continue;
1675 				mod->container->refs++;
1676 				error = linker_file_add_dependency(lf,
1677 				    mod->container);
1678 				if (error)
1679 					panic("cannot add dependency");
1680 			}
1681 		}
1682 		/*
1683 		 * Now do relocation etc using the symbol search paths
1684 		 * established by the dependencies
1685 		 */
1686 		error = LINKER_LINK_PRELOAD_FINISH(lf);
1687 		if (error) {
1688 			printf("KLD file %s - could not finalize loading\n",
1689 			    lf->filename);
1690 			goto fail;
1691 		}
1692 		linker_file_register_modules(lf);
1693 		if (!TAILQ_EMPTY(&lf->modules))
1694 			lf->flags |= LINKER_FILE_MODULES;
1695 		if (linker_file_lookup_set(lf, "sysinit_set", &si_start,
1696 		    &si_stop, NULL) == 0)
1697 			sysinit_add(si_start, si_stop);
1698 		linker_file_register_sysctls(lf, true);
1699 		lf->flags |= LINKER_FILE_LINKED;
1700 		continue;
1701 fail:
1702 		TAILQ_REMOVE(&depended_files, lf, loaded);
1703 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1704 	}
1705 	sx_xunlock(&kld_sx);
1706 	/* woohoo! we made it! */
1707 }
1708 
1709 SYSINIT(preload, SI_SUB_KLD, SI_ORDER_MIDDLE, linker_preload, NULL);
1710 
1711 /*
1712  * Handle preload files that failed to load any modules.
1713  */
1714 static void
1715 linker_preload_finish(void *arg)
1716 {
1717 	linker_file_t lf, nlf;
1718 
1719 	sx_xlock(&kld_sx);
1720 	TAILQ_FOREACH_SAFE(lf, &linker_files, link, nlf) {
1721 		/*
1722 		 * If all of the modules in this file failed to load, unload
1723 		 * the file and return an error of ENOEXEC.  (Parity with
1724 		 * linker_load_file.)
1725 		 */
1726 		if ((lf->flags & LINKER_FILE_MODULES) != 0 &&
1727 		    TAILQ_EMPTY(&lf->modules)) {
1728 			linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1729 			continue;
1730 		}
1731 
1732 		lf->flags &= ~LINKER_FILE_MODULES;
1733 		lf->userrefs++;	/* so we can (try to) kldunload it */
1734 	}
1735 	sx_xunlock(&kld_sx);
1736 }
1737 
1738 /*
1739  * Attempt to run after all DECLARE_MODULE SYSINITs.  Unfortunately they can be
1740  * scheduled at any subsystem and order, so run this as late as possible.  init
1741  * becomes runnable in SI_SUB_KTHREAD_INIT, so go slightly before that.
1742  */
1743 SYSINIT(preload_finish, SI_SUB_KTHREAD_INIT - 100, SI_ORDER_MIDDLE,
1744     linker_preload_finish, NULL);
1745 
1746 /*
1747  * Search for a not-loaded module by name.
1748  *
1749  * Modules may be found in the following locations:
1750  *
1751  * - preloaded (result is just the module name) - on disk (result is full path
1752  * to module)
1753  *
1754  * If the module name is qualified in any way (contains path, etc.) the we
1755  * simply return a copy of it.
1756  *
1757  * The search path can be manipulated via sysctl.  Note that we use the ';'
1758  * character as a separator to be consistent with the bootloader.
1759  */
1760 
1761 static char linker_hintfile[] = "linker.hints";
1762 static char linker_path[MAXPATHLEN] = "/boot/kernel;/boot/modules";
1763 
1764 SYSCTL_STRING(_kern, OID_AUTO, module_path, CTLFLAG_RWTUN, linker_path,
1765     sizeof(linker_path), "module load search path");
1766 
1767 TUNABLE_STR("module_path", linker_path, sizeof(linker_path));
1768 
1769 static char *linker_ext_list[] = {
1770 	"",
1771 	".ko",
1772 	NULL
1773 };
1774 
1775 /*
1776  * Check if file actually exists either with or without extension listed in
1777  * the linker_ext_list. (probably should be generic for the rest of the
1778  * kernel)
1779  */
1780 static char *
1781 linker_lookup_file(const char *path, int pathlen, const char *name,
1782     int namelen, struct vattr *vap)
1783 {
1784 	struct nameidata nd;
1785 	struct thread *td = curthread;	/* XXX */
1786 	char *result, **cpp, *sep;
1787 	int error, len, extlen, reclen, flags;
1788 	enum vtype type;
1789 
1790 	extlen = 0;
1791 	for (cpp = linker_ext_list; *cpp; cpp++) {
1792 		len = strlen(*cpp);
1793 		if (len > extlen)
1794 			extlen = len;
1795 	}
1796 	extlen++;		/* trailing '\0' */
1797 	sep = (path[pathlen - 1] != '/') ? "/" : "";
1798 
1799 	reclen = pathlen + strlen(sep) + namelen + extlen + 1;
1800 	result = malloc(reclen, M_LINKER, M_WAITOK);
1801 	for (cpp = linker_ext_list; *cpp; cpp++) {
1802 		snprintf(result, reclen, "%.*s%s%.*s%s", pathlen, path, sep,
1803 		    namelen, name, *cpp);
1804 		/*
1805 		 * Attempt to open the file, and return the path if
1806 		 * we succeed and it's a regular file.
1807 		 */
1808 		NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, result, td);
1809 		flags = FREAD;
1810 		error = vn_open(&nd, &flags, 0, NULL);
1811 		if (error == 0) {
1812 			NDFREE(&nd, NDF_ONLY_PNBUF);
1813 			type = nd.ni_vp->v_type;
1814 			if (vap)
1815 				VOP_GETATTR(nd.ni_vp, vap, td->td_ucred);
1816 			VOP_UNLOCK(nd.ni_vp, 0);
1817 			vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1818 			if (type == VREG)
1819 				return (result);
1820 		}
1821 	}
1822 	free(result, M_LINKER);
1823 	return (NULL);
1824 }
1825 
1826 #define	INT_ALIGN(base, ptr)	ptr =					\
1827 	(base) + roundup2((ptr) - (base), sizeof(int))
1828 
1829 /*
1830  * Lookup KLD which contains requested module in the "linker.hints" file. If
1831  * version specification is available, then try to find the best KLD.
1832  * Otherwise just find the latest one.
1833  */
1834 static char *
1835 linker_hints_lookup(const char *path, int pathlen, const char *modname,
1836     int modnamelen, const struct mod_depend *verinfo)
1837 {
1838 	struct thread *td = curthread;	/* XXX */
1839 	struct ucred *cred = td ? td->td_ucred : NULL;
1840 	struct nameidata nd;
1841 	struct vattr vattr, mattr;
1842 	u_char *hints = NULL;
1843 	u_char *cp, *recptr, *bufend, *result, *best, *pathbuf, *sep;
1844 	int error, ival, bestver, *intp, found, flags, clen, blen;
1845 	ssize_t reclen;
1846 
1847 	result = NULL;
1848 	bestver = found = 0;
1849 
1850 	sep = (path[pathlen - 1] != '/') ? "/" : "";
1851 	reclen = imax(modnamelen, strlen(linker_hintfile)) + pathlen +
1852 	    strlen(sep) + 1;
1853 	pathbuf = malloc(reclen, M_LINKER, M_WAITOK);
1854 	snprintf(pathbuf, reclen, "%.*s%s%s", pathlen, path, sep,
1855 	    linker_hintfile);
1856 
1857 	NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, pathbuf, td);
1858 	flags = FREAD;
1859 	error = vn_open(&nd, &flags, 0, NULL);
1860 	if (error)
1861 		goto bad;
1862 	NDFREE(&nd, NDF_ONLY_PNBUF);
1863 	if (nd.ni_vp->v_type != VREG)
1864 		goto bad;
1865 	best = cp = NULL;
1866 	error = VOP_GETATTR(nd.ni_vp, &vattr, cred);
1867 	if (error)
1868 		goto bad;
1869 	/*
1870 	 * XXX: we need to limit this number to some reasonable value
1871 	 */
1872 	if (vattr.va_size > LINKER_HINTS_MAX) {
1873 		printf("hints file too large %ld\n", (long)vattr.va_size);
1874 		goto bad;
1875 	}
1876 	hints = malloc(vattr.va_size, M_TEMP, M_WAITOK);
1877 	error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)hints, vattr.va_size, 0,
1878 	    UIO_SYSSPACE, IO_NODELOCKED, cred, NOCRED, &reclen, td);
1879 	if (error)
1880 		goto bad;
1881 	VOP_UNLOCK(nd.ni_vp, 0);
1882 	vn_close(nd.ni_vp, FREAD, cred, td);
1883 	nd.ni_vp = NULL;
1884 	if (reclen != 0) {
1885 		printf("can't read %zd\n", reclen);
1886 		goto bad;
1887 	}
1888 	intp = (int *)hints;
1889 	ival = *intp++;
1890 	if (ival != LINKER_HINTS_VERSION) {
1891 		printf("hints file version mismatch %d\n", ival);
1892 		goto bad;
1893 	}
1894 	bufend = hints + vattr.va_size;
1895 	recptr = (u_char *)intp;
1896 	clen = blen = 0;
1897 	while (recptr < bufend && !found) {
1898 		intp = (int *)recptr;
1899 		reclen = *intp++;
1900 		ival = *intp++;
1901 		cp = (char *)intp;
1902 		switch (ival) {
1903 		case MDT_VERSION:
1904 			clen = *cp++;
1905 			if (clen != modnamelen || bcmp(cp, modname, clen) != 0)
1906 				break;
1907 			cp += clen;
1908 			INT_ALIGN(hints, cp);
1909 			ival = *(int *)cp;
1910 			cp += sizeof(int);
1911 			clen = *cp++;
1912 			if (verinfo == NULL ||
1913 			    ival == verinfo->md_ver_preferred) {
1914 				found = 1;
1915 				break;
1916 			}
1917 			if (ival >= verinfo->md_ver_minimum &&
1918 			    ival <= verinfo->md_ver_maximum &&
1919 			    ival > bestver) {
1920 				bestver = ival;
1921 				best = cp;
1922 				blen = clen;
1923 			}
1924 			break;
1925 		default:
1926 			break;
1927 		}
1928 		recptr += reclen + sizeof(int);
1929 	}
1930 	/*
1931 	 * Finally check if KLD is in the place
1932 	 */
1933 	if (found)
1934 		result = linker_lookup_file(path, pathlen, cp, clen, &mattr);
1935 	else if (best)
1936 		result = linker_lookup_file(path, pathlen, best, blen, &mattr);
1937 
1938 	/*
1939 	 * KLD is newer than hints file. What we should do now?
1940 	 */
1941 	if (result && timespeccmp(&mattr.va_mtime, &vattr.va_mtime, >))
1942 		printf("warning: KLD '%s' is newer than the linker.hints"
1943 		    " file\n", result);
1944 bad:
1945 	free(pathbuf, M_LINKER);
1946 	if (hints)
1947 		free(hints, M_TEMP);
1948 	if (nd.ni_vp != NULL) {
1949 		VOP_UNLOCK(nd.ni_vp, 0);
1950 		vn_close(nd.ni_vp, FREAD, cred, td);
1951 	}
1952 	/*
1953 	 * If nothing found or hints is absent - fallback to the old
1954 	 * way by using "kldname[.ko]" as module name.
1955 	 */
1956 	if (!found && !bestver && result == NULL)
1957 		result = linker_lookup_file(path, pathlen, modname,
1958 		    modnamelen, NULL);
1959 	return (result);
1960 }
1961 
1962 /*
1963  * Lookup KLD which contains requested module in the all directories.
1964  */
1965 static char *
1966 linker_search_module(const char *modname, int modnamelen,
1967     const struct mod_depend *verinfo)
1968 {
1969 	char *cp, *ep, *result;
1970 
1971 	/*
1972 	 * traverse the linker path
1973 	 */
1974 	for (cp = linker_path; *cp; cp = ep + 1) {
1975 		/* find the end of this component */
1976 		for (ep = cp; (*ep != 0) && (*ep != ';'); ep++);
1977 		result = linker_hints_lookup(cp, ep - cp, modname,
1978 		    modnamelen, verinfo);
1979 		if (result != NULL)
1980 			return (result);
1981 		if (*ep == 0)
1982 			break;
1983 	}
1984 	return (NULL);
1985 }
1986 
1987 /*
1988  * Search for module in all directories listed in the linker_path.
1989  */
1990 static char *
1991 linker_search_kld(const char *name)
1992 {
1993 	char *cp, *ep, *result;
1994 	int len;
1995 
1996 	/* qualified at all? */
1997 	if (strchr(name, '/'))
1998 		return (strdup(name, M_LINKER));
1999 
2000 	/* traverse the linker path */
2001 	len = strlen(name);
2002 	for (ep = linker_path; *ep; ep++) {
2003 		cp = ep;
2004 		/* find the end of this component */
2005 		for (; *ep != 0 && *ep != ';'; ep++);
2006 		result = linker_lookup_file(cp, ep - cp, name, len, NULL);
2007 		if (result != NULL)
2008 			return (result);
2009 	}
2010 	return (NULL);
2011 }
2012 
2013 static const char *
2014 linker_basename(const char *path)
2015 {
2016 	const char *filename;
2017 
2018 	filename = strrchr(path, '/');
2019 	if (filename == NULL)
2020 		return path;
2021 	if (filename[1])
2022 		filename++;
2023 	return (filename);
2024 }
2025 
2026 #ifdef HWPMC_HOOKS
2027 /*
2028  * Inform hwpmc about the set of kernel modules currently loaded.
2029  */
2030 void *
2031 linker_hwpmc_list_objects(void)
2032 {
2033 	linker_file_t lf;
2034 	struct pmckern_map_in *kobase;
2035 	int i, nmappings;
2036 
2037 	nmappings = 0;
2038 	sx_slock(&kld_sx);
2039 	TAILQ_FOREACH(lf, &linker_files, link)
2040 		nmappings++;
2041 
2042 	/* Allocate nmappings + 1 entries. */
2043 	kobase = malloc((nmappings + 1) * sizeof(struct pmckern_map_in),
2044 	    M_LINKER, M_WAITOK | M_ZERO);
2045 	i = 0;
2046 	TAILQ_FOREACH(lf, &linker_files, link) {
2047 
2048 		/* Save the info for this linker file. */
2049 		kobase[i].pm_file = lf->filename;
2050 		kobase[i].pm_address = (uintptr_t)lf->address;
2051 		i++;
2052 	}
2053 	sx_sunlock(&kld_sx);
2054 
2055 	KASSERT(i > 0, ("linker_hpwmc_list_objects: no kernel objects?"));
2056 
2057 	/* The last entry of the malloced area comprises of all zeros. */
2058 	KASSERT(kobase[i].pm_file == NULL,
2059 	    ("linker_hwpmc_list_objects: last object not NULL"));
2060 
2061 	return ((void *)kobase);
2062 }
2063 #endif
2064 
2065 /*
2066  * Find a file which contains given module and load it, if "parent" is not
2067  * NULL, register a reference to it.
2068  */
2069 static int
2070 linker_load_module(const char *kldname, const char *modname,
2071     struct linker_file *parent, const struct mod_depend *verinfo,
2072     struct linker_file **lfpp)
2073 {
2074 	linker_file_t lfdep;
2075 	const char *filename;
2076 	char *pathname;
2077 	int error;
2078 
2079 	sx_assert(&kld_sx, SA_XLOCKED);
2080 	if (modname == NULL) {
2081 		/*
2082  		 * We have to load KLD
2083  		 */
2084 		KASSERT(verinfo == NULL, ("linker_load_module: verinfo"
2085 		    " is not NULL"));
2086 		/* check if root file system is not mounted */
2087 		if (rootvnode == NULL || curproc->p_fd->fd_rdir == NULL)
2088 			return (ENXIO);
2089 		pathname = linker_search_kld(kldname);
2090 	} else {
2091 		if (modlist_lookup2(modname, verinfo) != NULL)
2092 			return (EEXIST);
2093 		/* check if root file system is not mounted */
2094 		if (rootvnode == NULL || curproc->p_fd->fd_rdir == NULL)
2095 			return (ENXIO);
2096 		if (kldname != NULL)
2097 			pathname = strdup(kldname, M_LINKER);
2098 		else
2099 			/*
2100 			 * Need to find a KLD with required module
2101 			 */
2102 			pathname = linker_search_module(modname,
2103 			    strlen(modname), verinfo);
2104 	}
2105 	if (pathname == NULL)
2106 		return (ENOENT);
2107 
2108 	/*
2109 	 * Can't load more than one file with the same basename XXX:
2110 	 * Actually it should be possible to have multiple KLDs with
2111 	 * the same basename but different path because they can
2112 	 * provide different versions of the same modules.
2113 	 */
2114 	filename = linker_basename(pathname);
2115 	if (linker_find_file_by_name(filename))
2116 		error = EEXIST;
2117 	else do {
2118 		error = linker_load_file(pathname, &lfdep);
2119 		if (error)
2120 			break;
2121 		if (modname && verinfo &&
2122 		    modlist_lookup2(modname, verinfo) == NULL) {
2123 			linker_file_unload(lfdep, LINKER_UNLOAD_FORCE);
2124 			error = ENOENT;
2125 			break;
2126 		}
2127 		if (parent) {
2128 			error = linker_file_add_dependency(parent, lfdep);
2129 			if (error)
2130 				break;
2131 		}
2132 		if (lfpp)
2133 			*lfpp = lfdep;
2134 	} while (0);
2135 	free(pathname, M_LINKER);
2136 	return (error);
2137 }
2138 
2139 /*
2140  * This routine is responsible for finding dependencies of userland initiated
2141  * kldload(2)'s of files.
2142  */
2143 int
2144 linker_load_dependencies(linker_file_t lf)
2145 {
2146 	linker_file_t lfdep;
2147 	struct mod_metadata **start, **stop, **mdp, **nmdp;
2148 	struct mod_metadata *mp, *nmp;
2149 	const struct mod_depend *verinfo;
2150 	modlist_t mod;
2151 	const char *modname, *nmodname;
2152 	int ver, error = 0;
2153 
2154 	/*
2155 	 * All files are dependent on /kernel.
2156 	 */
2157 	sx_assert(&kld_sx, SA_XLOCKED);
2158 	if (linker_kernel_file) {
2159 		linker_kernel_file->refs++;
2160 		error = linker_file_add_dependency(lf, linker_kernel_file);
2161 		if (error)
2162 			return (error);
2163 	}
2164 	if (linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop,
2165 	    NULL) != 0)
2166 		return (0);
2167 	for (mdp = start; mdp < stop; mdp++) {
2168 		mp = *mdp;
2169 		if (mp->md_type != MDT_VERSION)
2170 			continue;
2171 		modname = mp->md_cval;
2172 		ver = ((const struct mod_version *)mp->md_data)->mv_version;
2173 		mod = modlist_lookup(modname, ver);
2174 		if (mod != NULL) {
2175 			printf("interface %s.%d already present in the KLD"
2176 			    " '%s'!\n", modname, ver,
2177 			    mod->container->filename);
2178 			return (EEXIST);
2179 		}
2180 	}
2181 
2182 	for (mdp = start; mdp < stop; mdp++) {
2183 		mp = *mdp;
2184 		if (mp->md_type != MDT_DEPEND)
2185 			continue;
2186 		modname = mp->md_cval;
2187 		verinfo = mp->md_data;
2188 		nmodname = NULL;
2189 		for (nmdp = start; nmdp < stop; nmdp++) {
2190 			nmp = *nmdp;
2191 			if (nmp->md_type != MDT_VERSION)
2192 				continue;
2193 			nmodname = nmp->md_cval;
2194 			if (strcmp(modname, nmodname) == 0)
2195 				break;
2196 		}
2197 		if (nmdp < stop)/* early exit, it's a self reference */
2198 			continue;
2199 		mod = modlist_lookup2(modname, verinfo);
2200 		if (mod) {	/* woohoo, it's loaded already */
2201 			lfdep = mod->container;
2202 			lfdep->refs++;
2203 			error = linker_file_add_dependency(lf, lfdep);
2204 			if (error)
2205 				break;
2206 			continue;
2207 		}
2208 		error = linker_load_module(NULL, modname, lf, verinfo, NULL);
2209 		if (error) {
2210 			printf("KLD %s: depends on %s - not available or"
2211 			    " version mismatch\n", lf->filename, modname);
2212 			break;
2213 		}
2214 	}
2215 
2216 	if (error)
2217 		return (error);
2218 	linker_addmodules(lf, start, stop, 0);
2219 	return (error);
2220 }
2221 
2222 static int
2223 sysctl_kern_function_list_iterate(const char *name, void *opaque)
2224 {
2225 	struct sysctl_req *req;
2226 
2227 	req = opaque;
2228 	return (SYSCTL_OUT(req, name, strlen(name) + 1));
2229 }
2230 
2231 /*
2232  * Export a nul-separated, double-nul-terminated list of all function names
2233  * in the kernel.
2234  */
2235 static int
2236 sysctl_kern_function_list(SYSCTL_HANDLER_ARGS)
2237 {
2238 	linker_file_t lf;
2239 	int error;
2240 
2241 #ifdef MAC
2242 	error = mac_kld_check_stat(req->td->td_ucred);
2243 	if (error)
2244 		return (error);
2245 #endif
2246 	error = sysctl_wire_old_buffer(req, 0);
2247 	if (error != 0)
2248 		return (error);
2249 	sx_xlock(&kld_sx);
2250 	TAILQ_FOREACH(lf, &linker_files, link) {
2251 		error = LINKER_EACH_FUNCTION_NAME(lf,
2252 		    sysctl_kern_function_list_iterate, req);
2253 		if (error) {
2254 			sx_xunlock(&kld_sx);
2255 			return (error);
2256 		}
2257 	}
2258 	sx_xunlock(&kld_sx);
2259 	return (SYSCTL_OUT(req, "", 1));
2260 }
2261 
2262 SYSCTL_PROC(_kern, OID_AUTO, function_list, CTLTYPE_OPAQUE | CTLFLAG_RD,
2263     NULL, 0, sysctl_kern_function_list, "", "kernel function list");
2264