xref: /freebsd/sys/kern/kern_linker.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
1 /*-
2  * Copyright (c) 1997-2000 Doug Rabson
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include "opt_ddb.h"
31 #include "opt_hwpmc_hooks.h"
32 #include "opt_mac.h"
33 
34 #include <sys/param.h>
35 #include <sys/kernel.h>
36 #include <sys/systm.h>
37 #include <sys/malloc.h>
38 #include <sys/sysproto.h>
39 #include <sys/sysent.h>
40 #include <sys/priv.h>
41 #include <sys/proc.h>
42 #include <sys/lock.h>
43 #include <sys/mutex.h>
44 #include <sys/sx.h>
45 #include <sys/module.h>
46 #include <sys/mount.h>
47 #include <sys/linker.h>
48 #include <sys/fcntl.h>
49 #include <sys/libkern.h>
50 #include <sys/namei.h>
51 #include <sys/vnode.h>
52 #include <sys/syscallsubr.h>
53 #include <sys/sysctl.h>
54 
55 #include <security/mac/mac_framework.h>
56 
57 #include "linker_if.h"
58 
59 #ifdef HWPMC_HOOKS
60 #include <sys/pmckern.h>
61 #endif
62 
63 #ifdef KLD_DEBUG
64 int kld_debug = 0;
65 #endif
66 
67 #define	KLD_LOCK()		sx_xlock(&kld_sx)
68 #define	KLD_UNLOCK()		sx_xunlock(&kld_sx)
69 #define	KLD_LOCKED()		sx_xlocked(&kld_sx)
70 #define	KLD_LOCK_ASSERT() do {						\
71 	if (!cold)							\
72 		sx_assert(&kld_sx, SX_XLOCKED);				\
73 } while (0)
74 
75 /*
76  * static char *linker_search_path(const char *name, struct mod_depend
77  * *verinfo);
78  */
79 static const char 	*linker_basename(const char *path);
80 
81 /*
82  * Find a currently loaded file given its filename.
83  */
84 static linker_file_t linker_find_file_by_name(const char* _filename);
85 
86 /*
87  * Find a currently loaded file given its file id.
88  */
89 static linker_file_t linker_find_file_by_id(int _fileid);
90 
91 /* Metadata from the static kernel */
92 SET_DECLARE(modmetadata_set, struct mod_metadata);
93 
94 MALLOC_DEFINE(M_LINKER, "linker", "kernel linker");
95 
96 linker_file_t linker_kernel_file;
97 
98 static struct sx kld_sx;	/* kernel linker lock */
99 
100 /*
101  * Load counter used by clients to determine if a linker file has been
102  * re-loaded. This counter is incremented for each file load.
103  */
104 static int loadcnt;
105 
106 static linker_class_list_t classes;
107 static linker_file_list_t linker_files;
108 static int next_file_id = 1;
109 static int linker_no_more_classes = 0;
110 
111 #define	LINKER_GET_NEXT_FILE_ID(a) do {					\
112 	linker_file_t lftmp;						\
113 									\
114 	KLD_LOCK_ASSERT();						\
115 retry:									\
116 	TAILQ_FOREACH(lftmp, &linker_files, link) {			\
117 		if (next_file_id == lftmp->id) {			\
118 			next_file_id++;					\
119 			goto retry;					\
120 		}							\
121 	}								\
122 	(a) = next_file_id;						\
123 } while(0)
124 
125 
126 /* XXX wrong name; we're looking at version provision tags here, not modules */
127 typedef TAILQ_HEAD(, modlist) modlisthead_t;
128 struct modlist {
129 	TAILQ_ENTRY(modlist) link;	/* chain together all modules */
130 	linker_file_t   container;
131 	const char 	*name;
132 	int             version;
133 };
134 typedef struct modlist *modlist_t;
135 static modlisthead_t found_modules;
136 
137 static int	linker_file_add_dependency(linker_file_t file,
138 		    linker_file_t dep);
139 static caddr_t	linker_file_lookup_symbol_internal(linker_file_t file,
140 		    const char* name, int deps);
141 static int	linker_load_module(const char *kldname,
142 		    const char *modname, struct linker_file *parent,
143 		    struct mod_depend *verinfo, struct linker_file **lfpp);
144 static modlist_t modlist_lookup2(const char *name, struct mod_depend *verinfo);
145 
146 static char *
147 linker_strdup(const char *str)
148 {
149 	char *result;
150 
151 	if ((result = malloc((strlen(str) + 1), M_LINKER, M_WAITOK)) != NULL)
152 		strcpy(result, str);
153 	return (result);
154 }
155 
156 static void
157 linker_init(void *arg)
158 {
159 
160 	sx_init(&kld_sx, "kernel linker");
161 	TAILQ_INIT(&classes);
162 	TAILQ_INIT(&linker_files);
163 }
164 
165 SYSINIT(linker, SI_SUB_KLD, SI_ORDER_FIRST, linker_init, 0)
166 
167 static void
168 linker_stop_class_add(void *arg)
169 {
170 
171 	linker_no_more_classes = 1;
172 }
173 
174 SYSINIT(linker_class, SI_SUB_KLD, SI_ORDER_ANY, linker_stop_class_add, NULL)
175 
176 int
177 linker_add_class(linker_class_t lc)
178 {
179 
180 	/*
181 	 * We disallow any class registration past SI_ORDER_ANY
182 	 * of SI_SUB_KLD.  We bump the reference count to keep the
183 	 * ops from being freed.
184 	 */
185 	if (linker_no_more_classes == 1)
186 		return (EPERM);
187 	kobj_class_compile((kobj_class_t) lc);
188 	((kobj_class_t)lc)->refs++;	/* XXX: kobj_mtx */
189 	TAILQ_INSERT_TAIL(&classes, lc, link);
190 	return (0);
191 }
192 
193 static void
194 linker_file_sysinit(linker_file_t lf)
195 {
196 	struct sysinit **start, **stop, **sipp, **xipp, *save;
197 
198 	KLD_DPF(FILE, ("linker_file_sysinit: calling SYSINITs for %s\n",
199 	    lf->filename));
200 
201 	if (linker_file_lookup_set(lf, "sysinit_set", &start, &stop, NULL) != 0)
202 		return;
203 	/*
204 	 * Perform a bubble sort of the system initialization objects by
205 	 * their subsystem (primary key) and order (secondary key).
206 	 *
207 	 * Since some things care about execution order, this is the operation
208 	 * which ensures continued function.
209 	 */
210 	for (sipp = start; sipp < stop; sipp++) {
211 		for (xipp = sipp + 1; xipp < stop; xipp++) {
212 			if ((*sipp)->subsystem < (*xipp)->subsystem ||
213 			    ((*sipp)->subsystem == (*xipp)->subsystem &&
214 			    (*sipp)->order <= (*xipp)->order))
215 				continue;	/* skip */
216 			save = *sipp;
217 			*sipp = *xipp;
218 			*xipp = save;
219 		}
220 	}
221 
222 	/*
223 	 * Traverse the (now) ordered list of system initialization tasks.
224 	 * Perform each task, and continue on to the next task.
225 	 */
226 	mtx_lock(&Giant);
227 	for (sipp = start; sipp < stop; sipp++) {
228 		if ((*sipp)->subsystem == SI_SUB_DUMMY)
229 			continue;	/* skip dummy task(s) */
230 
231 		/* Call function */
232 		(*((*sipp)->func)) ((*sipp)->udata);
233 	}
234 	mtx_unlock(&Giant);
235 }
236 
237 static void
238 linker_file_sysuninit(linker_file_t lf)
239 {
240 	struct sysinit **start, **stop, **sipp, **xipp, *save;
241 
242 	KLD_DPF(FILE, ("linker_file_sysuninit: calling SYSUNINITs for %s\n",
243 	    lf->filename));
244 
245 	if (linker_file_lookup_set(lf, "sysuninit_set", &start, &stop,
246 	    NULL) != 0)
247 		return;
248 
249 	/*
250 	 * Perform a reverse bubble sort of the system initialization objects
251 	 * by their subsystem (primary key) and order (secondary key).
252 	 *
253 	 * Since some things care about execution order, this is the operation
254 	 * which ensures continued function.
255 	 */
256 	for (sipp = start; sipp < stop; sipp++) {
257 		for (xipp = sipp + 1; xipp < stop; xipp++) {
258 			if ((*sipp)->subsystem > (*xipp)->subsystem ||
259 			    ((*sipp)->subsystem == (*xipp)->subsystem &&
260 			    (*sipp)->order >= (*xipp)->order))
261 				continue;	/* skip */
262 			save = *sipp;
263 			*sipp = *xipp;
264 			*xipp = save;
265 		}
266 	}
267 
268 	/*
269 	 * Traverse the (now) ordered list of system initialization tasks.
270 	 * Perform each task, and continue on to the next task.
271 	 */
272 	mtx_lock(&Giant);
273 	for (sipp = start; sipp < stop; sipp++) {
274 		if ((*sipp)->subsystem == SI_SUB_DUMMY)
275 			continue;	/* skip dummy task(s) */
276 
277 		/* Call function */
278 		(*((*sipp)->func)) ((*sipp)->udata);
279 	}
280 	mtx_unlock(&Giant);
281 }
282 
283 static void
284 linker_file_register_sysctls(linker_file_t lf)
285 {
286 	struct sysctl_oid **start, **stop, **oidp;
287 
288 	KLD_DPF(FILE,
289 	    ("linker_file_register_sysctls: registering SYSCTLs for %s\n",
290 	    lf->filename));
291 
292 	if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
293 		return;
294 
295 	mtx_lock(&Giant);
296 	for (oidp = start; oidp < stop; oidp++)
297 		sysctl_register_oid(*oidp);
298 	mtx_unlock(&Giant);
299 }
300 
301 static void
302 linker_file_unregister_sysctls(linker_file_t lf)
303 {
304 	struct sysctl_oid **start, **stop, **oidp;
305 
306 	KLD_DPF(FILE, ("linker_file_unregister_sysctls: registering SYSCTLs"
307 	    " for %s\n", lf->filename));
308 
309 	if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
310 		return;
311 
312 	mtx_lock(&Giant);
313 	for (oidp = start; oidp < stop; oidp++)
314 		sysctl_unregister_oid(*oidp);
315 	mtx_unlock(&Giant);
316 }
317 
318 static int
319 linker_file_register_modules(linker_file_t lf)
320 {
321 	struct mod_metadata **start, **stop, **mdp;
322 	const moduledata_t *moddata;
323 	int first_error, error;
324 
325 	KLD_DPF(FILE, ("linker_file_register_modules: registering modules"
326 	    " in %s\n", lf->filename));
327 
328 	if (linker_file_lookup_set(lf, "modmetadata_set", &start,
329 	    &stop, NULL) != 0) {
330 		/*
331 		 * This fallback should be unnecessary, but if we get booted
332 		 * from boot2 instead of loader and we are missing our
333 		 * metadata then we have to try the best we can.
334 		 */
335 		if (lf == linker_kernel_file) {
336 			start = SET_BEGIN(modmetadata_set);
337 			stop = SET_LIMIT(modmetadata_set);
338 		} else
339 			return (0);
340 	}
341 	first_error = 0;
342 	for (mdp = start; mdp < stop; mdp++) {
343 		if ((*mdp)->md_type != MDT_MODULE)
344 			continue;
345 		moddata = (*mdp)->md_data;
346 		KLD_DPF(FILE, ("Registering module %s in %s\n",
347 		    moddata->name, lf->filename));
348 		error = module_register(moddata, lf);
349 		if (error) {
350 			printf("Module %s failed to register: %d\n",
351 			    moddata->name, error);
352 			if (first_error == 0)
353 				first_error = error;
354 		}
355 	}
356 	return (first_error);
357 }
358 
359 static void
360 linker_init_kernel_modules(void)
361 {
362 
363 	linker_file_register_modules(linker_kernel_file);
364 }
365 
366 SYSINIT(linker_kernel, SI_SUB_KLD, SI_ORDER_ANY, linker_init_kernel_modules, 0)
367 
368 static int
369 linker_load_file(const char *filename, linker_file_t *result)
370 {
371 	linker_class_t lc;
372 	linker_file_t lf;
373 	int foundfile, error;
374 
375 	/* Refuse to load modules if securelevel raised */
376 	if (securelevel > 0)
377 		return (EPERM);
378 
379 	KLD_LOCK_ASSERT();
380 	lf = linker_find_file_by_name(filename);
381 	if (lf) {
382 		KLD_DPF(FILE, ("linker_load_file: file %s is already loaded,"
383 		    " incrementing refs\n", filename));
384 		*result = lf;
385 		lf->refs++;
386 		return (0);
387 	}
388 	foundfile = 0;
389 	error = 0;
390 
391 	/*
392 	 * We do not need to protect (lock) classes here because there is
393 	 * no class registration past startup (SI_SUB_KLD, SI_ORDER_ANY)
394 	 * and there is no class deregistration mechanism at this time.
395 	 */
396 	TAILQ_FOREACH(lc, &classes, link) {
397 		KLD_DPF(FILE, ("linker_load_file: trying to load %s\n",
398 		    filename));
399 		error = LINKER_LOAD_FILE(lc, filename, &lf);
400 		/*
401 		 * If we got something other than ENOENT, then it exists but
402 		 * we cannot load it for some other reason.
403 		 */
404 		if (error != ENOENT)
405 			foundfile = 1;
406 		if (lf) {
407 			error = linker_file_register_modules(lf);
408 			if (error == EEXIST) {
409 				linker_file_unload(lf, LINKER_UNLOAD_FORCE);
410 				return (error);
411 			}
412 			KLD_UNLOCK();
413 			linker_file_register_sysctls(lf);
414 			linker_file_sysinit(lf);
415 			KLD_LOCK();
416 			lf->flags |= LINKER_FILE_LINKED;
417 			*result = lf;
418 			return (0);
419 		}
420 	}
421 	/*
422 	 * Less than ideal, but tells the user whether it failed to load or
423 	 * the module was not found.
424 	 */
425 	if (foundfile) {
426 		/*
427 		 * Format not recognized or otherwise unloadable.
428 		 * When loading a module that is statically built into
429 		 * the kernel EEXIST percolates back up as the return
430 		 * value.  Preserve this so that apps like sysinstall
431 		 * can recognize this special case and not post bogus
432 		 * dialog boxes.
433 		 */
434 		if (error != EEXIST)
435 			error = ENOEXEC;
436 	} else
437 		error = ENOENT;		/* Nothing found */
438 	return (error);
439 }
440 
441 int
442 linker_reference_module(const char *modname, struct mod_depend *verinfo,
443     linker_file_t *result)
444 {
445 	modlist_t mod;
446 	int error;
447 
448 	KLD_LOCK();
449 	if ((mod = modlist_lookup2(modname, verinfo)) != NULL) {
450 		*result = mod->container;
451 		(*result)->refs++;
452 		KLD_UNLOCK();
453 		return (0);
454 	}
455 
456 	error = linker_load_module(NULL, modname, NULL, verinfo, result);
457 	KLD_UNLOCK();
458 	return (error);
459 }
460 
461 int
462 linker_release_module(const char *modname, struct mod_depend *verinfo,
463     linker_file_t lf)
464 {
465 	modlist_t mod;
466 	int error;
467 
468 	KLD_LOCK();
469 	if (lf == NULL) {
470 		KASSERT(modname != NULL,
471 		    ("linker_release_module: no file or name"));
472 		mod = modlist_lookup2(modname, verinfo);
473 		if (mod == NULL) {
474 			KLD_UNLOCK();
475 			return (ESRCH);
476 		}
477 		lf = mod->container;
478 	} else
479 		KASSERT(modname == NULL && verinfo == NULL,
480 		    ("linker_release_module: both file and name"));
481 	error =	linker_file_unload(lf, LINKER_UNLOAD_NORMAL);
482 	KLD_UNLOCK();
483 	return (error);
484 }
485 
486 static linker_file_t
487 linker_find_file_by_name(const char *filename)
488 {
489 	linker_file_t lf;
490 	char *koname;
491 
492 	koname = malloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
493 	sprintf(koname, "%s.ko", filename);
494 
495 	KLD_LOCK_ASSERT();
496 	TAILQ_FOREACH(lf, &linker_files, link) {
497 		if (strcmp(lf->filename, koname) == 0)
498 			break;
499 		if (strcmp(lf->filename, filename) == 0)
500 			break;
501 	}
502 	free(koname, M_LINKER);
503 	return (lf);
504 }
505 
506 static linker_file_t
507 linker_find_file_by_id(int fileid)
508 {
509 	linker_file_t lf;
510 
511 	KLD_LOCK_ASSERT();
512 	TAILQ_FOREACH(lf, &linker_files, link)
513 		if (lf->id == fileid && lf->flags & LINKER_FILE_LINKED)
514 			break;
515 	return (lf);
516 }
517 
518 int
519 linker_file_foreach(linker_predicate_t *predicate, void *context)
520 {
521 	linker_file_t lf;
522 	int retval = 0;
523 
524 	KLD_LOCK();
525 	TAILQ_FOREACH(lf, &linker_files, link) {
526 		retval = predicate(lf, context);
527 		if (retval != 0)
528 			break;
529 	}
530 	KLD_UNLOCK();
531 	return (retval);
532 }
533 
534 linker_file_t
535 linker_make_file(const char *pathname, linker_class_t lc)
536 {
537 	linker_file_t lf;
538 	const char *filename;
539 
540 	KLD_LOCK_ASSERT();
541 	filename = linker_basename(pathname);
542 
543 	KLD_DPF(FILE, ("linker_make_file: new file, filename='%s' for pathname='%s'\n", filename, pathname));
544 	lf = (linker_file_t)kobj_create((kobj_class_t)lc, M_LINKER, M_WAITOK);
545 	if (lf == NULL)
546 		return (NULL);
547 	lf->refs = 1;
548 	lf->userrefs = 0;
549 	lf->flags = 0;
550 	lf->filename = linker_strdup(filename);
551 	lf->pathname = linker_strdup(pathname);
552 	LINKER_GET_NEXT_FILE_ID(lf->id);
553 	lf->ndeps = 0;
554 	lf->deps = NULL;
555 	lf->loadcnt = ++loadcnt;
556 	lf->sdt_probes = NULL;
557 	lf->sdt_nprobes = 0;
558 	STAILQ_INIT(&lf->common);
559 	TAILQ_INIT(&lf->modules);
560 	TAILQ_INSERT_TAIL(&linker_files, lf, link);
561 	return (lf);
562 }
563 
564 int
565 linker_file_unload(linker_file_t file, int flags)
566 {
567 	module_t mod, next;
568 	modlist_t ml, nextml;
569 	struct common_symbol *cp;
570 	int error, i;
571 
572 	/* Refuse to unload modules if securelevel raised. */
573 	if (securelevel > 0)
574 		return (EPERM);
575 
576 	KLD_LOCK_ASSERT();
577 	KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
578 
579 	/* Easy case of just dropping a reference. */
580 	if (file->refs > 1) {
581 		file->refs--;
582 		return (0);
583 	}
584 
585 	KLD_DPF(FILE, ("linker_file_unload: file is unloading,"
586 	    " informing modules\n"));
587 
588 	/*
589 	 * Inform any modules associated with this file.
590 	 */
591 	MOD_XLOCK;
592 	for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
593 		next = module_getfnext(mod);
594 		MOD_XUNLOCK;
595 
596 		/*
597 		 * Give the module a chance to veto the unload.
598 		 */
599 		if ((error = module_unload(mod, flags)) != 0) {
600 			KLD_DPF(FILE, ("linker_file_unload: module %p"
601 			    " vetoes unload\n", mod));
602 			return (error);
603 		}
604 		MOD_XLOCK;
605 		module_release(mod);
606 	}
607 	MOD_XUNLOCK;
608 
609 	TAILQ_FOREACH_SAFE(ml, &found_modules, link, nextml) {
610 		if (ml->container == file) {
611 			TAILQ_REMOVE(&found_modules, ml, link);
612 			free(ml, M_LINKER);
613 		}
614 	}
615 
616 	/*
617 	 * Don't try to run SYSUNINITs if we are unloaded due to a
618 	 * link error.
619 	 */
620 	if (file->flags & LINKER_FILE_LINKED) {
621 		linker_file_sysuninit(file);
622 		linker_file_unregister_sysctls(file);
623 	}
624 	TAILQ_REMOVE(&linker_files, file, link);
625 
626 	if (file->deps) {
627 		for (i = 0; i < file->ndeps; i++)
628 			linker_file_unload(file->deps[i], flags);
629 		free(file->deps, M_LINKER);
630 		file->deps = NULL;
631 	}
632 	while ((cp = STAILQ_FIRST(&file->common)) != NULL) {
633 		STAILQ_REMOVE_HEAD(&file->common, link);
634 		free(cp, M_LINKER);
635 	}
636 
637 	LINKER_UNLOAD(file);
638 	if (file->filename) {
639 		free(file->filename, M_LINKER);
640 		file->filename = NULL;
641 	}
642 	if (file->pathname) {
643 		free(file->pathname, M_LINKER);
644 		file->pathname = NULL;
645 	}
646 	kobj_delete((kobj_t) file, M_LINKER);
647 	return (0);
648 }
649 
650 static int
651 linker_file_add_dependency(linker_file_t file, linker_file_t dep)
652 {
653 	linker_file_t *newdeps;
654 
655 	KLD_LOCK_ASSERT();
656 	newdeps = malloc((file->ndeps + 1) * sizeof(linker_file_t *),
657 	    M_LINKER, M_WAITOK | M_ZERO);
658 	if (newdeps == NULL)
659 		return (ENOMEM);
660 
661 	if (file->deps) {
662 		bcopy(file->deps, newdeps,
663 		    file->ndeps * sizeof(linker_file_t *));
664 		free(file->deps, M_LINKER);
665 	}
666 	file->deps = newdeps;
667 	file->deps[file->ndeps] = dep;
668 	file->ndeps++;
669 	return (0);
670 }
671 
672 /*
673  * Locate a linker set and its contents.  This is a helper function to avoid
674  * linker_if.h exposure elsewhere.  Note: firstp and lastp are really void **.
675  * This function is used in this file so we can avoid having lots of (void **)
676  * casts.
677  */
678 int
679 linker_file_lookup_set(linker_file_t file, const char *name,
680     void *firstp, void *lastp, int *countp)
681 {
682 	int error, locked;
683 
684 	locked = KLD_LOCKED();
685 	if (!locked)
686 		KLD_LOCK();
687 	error = LINKER_LOOKUP_SET(file, name, firstp, lastp, countp);
688 	if (!locked)
689 		KLD_UNLOCK();
690 	return (error);
691 }
692 
693 /*
694  * List all functions in a file.
695  */
696 int
697 linker_file_function_listall(linker_file_t lf,
698     int (*callback_func)(linker_file_t, linker_symval_t *, void *), void *arg)
699 {
700 	return (LINKER_EACH_FUNCTION_NAMEVAL(lf, callback_func, arg));
701 }
702 
703 caddr_t
704 linker_file_lookup_symbol(linker_file_t file, const char *name, int deps)
705 {
706 	caddr_t sym;
707 	int locked;
708 
709 	locked = KLD_LOCKED();
710 	if (!locked)
711 		KLD_LOCK();
712 	sym = linker_file_lookup_symbol_internal(file, name, deps);
713 	if (!locked)
714 		KLD_UNLOCK();
715 	return (sym);
716 }
717 
718 static caddr_t
719 linker_file_lookup_symbol_internal(linker_file_t file, const char *name,
720     int deps)
721 {
722 	c_linker_sym_t sym;
723 	linker_symval_t symval;
724 	caddr_t address;
725 	size_t common_size = 0;
726 	int i;
727 
728 	KLD_LOCK_ASSERT();
729 	KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n",
730 	    file, name, deps));
731 
732 	if (LINKER_LOOKUP_SYMBOL(file, name, &sym) == 0) {
733 		LINKER_SYMBOL_VALUES(file, sym, &symval);
734 		if (symval.value == 0)
735 			/*
736 			 * For commons, first look them up in the
737 			 * dependencies and only allocate space if not found
738 			 * there.
739 			 */
740 			common_size = symval.size;
741 		else {
742 			KLD_DPF(SYM, ("linker_file_lookup_symbol: symbol"
743 			    ".value=%p\n", symval.value));
744 			return (symval.value);
745 		}
746 	}
747 	if (deps) {
748 		for (i = 0; i < file->ndeps; i++) {
749 			address = linker_file_lookup_symbol_internal(
750 			    file->deps[i], name, 0);
751 			if (address) {
752 				KLD_DPF(SYM, ("linker_file_lookup_symbol:"
753 				    " deps value=%p\n", address));
754 				return (address);
755 			}
756 		}
757 	}
758 	if (common_size > 0) {
759 		/*
760 		 * This is a common symbol which was not found in the
761 		 * dependencies.  We maintain a simple common symbol table in
762 		 * the file object.
763 		 */
764 		struct common_symbol *cp;
765 
766 		STAILQ_FOREACH(cp, &file->common, link) {
767 			if (strcmp(cp->name, name) == 0) {
768 				KLD_DPF(SYM, ("linker_file_lookup_symbol:"
769 				    " old common value=%p\n", cp->address));
770 				return (cp->address);
771 			}
772 		}
773 		/*
774 		 * Round the symbol size up to align.
775 		 */
776 		common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
777 		cp = malloc(sizeof(struct common_symbol)
778 		    + common_size + strlen(name) + 1, M_LINKER,
779 		    M_WAITOK | M_ZERO);
780 		cp->address = (caddr_t)(cp + 1);
781 		cp->name = cp->address + common_size;
782 		strcpy(cp->name, name);
783 		bzero(cp->address, common_size);
784 		STAILQ_INSERT_TAIL(&file->common, cp, link);
785 
786 		KLD_DPF(SYM, ("linker_file_lookup_symbol: new common"
787 		    " value=%p\n", cp->address));
788 		return (cp->address);
789 	}
790 	KLD_DPF(SYM, ("linker_file_lookup_symbol: fail\n"));
791 	return (0);
792 }
793 
794 /*
795  * Both DDB and stack(9) rely on the kernel linker to provide forward and
796  * backward lookup of symbols.  However, DDB and sometimes stack(9) need to
797  * do this in a lockfree manner.  We provide a set of internal helper
798  * routines to perform these operations without locks, and then wrappers that
799  * optionally lock.
800  *
801  * linker_debug_lookup() is ifdef DDB as currently it's only used by DDB.
802  */
803 #ifdef DDB
804 static int
805 linker_debug_lookup(const char *symstr, c_linker_sym_t *sym)
806 {
807 	linker_file_t lf;
808 
809 	TAILQ_FOREACH(lf, &linker_files, link) {
810 		if (LINKER_LOOKUP_SYMBOL(lf, symstr, sym) == 0)
811 			return (0);
812 	}
813 	return (ENOENT);
814 }
815 #endif
816 
817 static int
818 linker_debug_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
819 {
820 	linker_file_t lf;
821 	c_linker_sym_t best, es;
822 	u_long diff, bestdiff, off;
823 
824 	best = 0;
825 	off = (uintptr_t)value;
826 	bestdiff = off;
827 	TAILQ_FOREACH(lf, &linker_files, link) {
828 		if (LINKER_SEARCH_SYMBOL(lf, value, &es, &diff) != 0)
829 			continue;
830 		if (es != 0 && diff < bestdiff) {
831 			best = es;
832 			bestdiff = diff;
833 		}
834 		if (bestdiff == 0)
835 			break;
836 	}
837 	if (best) {
838 		*sym = best;
839 		*diffp = bestdiff;
840 		return (0);
841 	} else {
842 		*sym = 0;
843 		*diffp = off;
844 		return (ENOENT);
845 	}
846 }
847 
848 static int
849 linker_debug_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
850 {
851 	linker_file_t lf;
852 
853 	TAILQ_FOREACH(lf, &linker_files, link) {
854 		if (LINKER_SYMBOL_VALUES(lf, sym, symval) == 0)
855 			return (0);
856 	}
857 	return (ENOENT);
858 }
859 
860 static int
861 linker_debug_search_symbol_name(caddr_t value, char *buf, u_int buflen,
862     long *offset)
863 {
864 	linker_symval_t symval;
865 	c_linker_sym_t sym;
866 	int error;
867 
868 	*offset = 0;
869 	error = linker_debug_search_symbol(value, &sym, offset);
870 	if (error)
871 		return (error);
872 	error = linker_debug_symbol_values(sym, &symval);
873 	if (error)
874 		return (error);
875 	strlcpy(buf, symval.name, buflen);
876 	return (0);
877 }
878 
879 #ifdef DDB
880 /*
881  * DDB Helpers.  DDB has to look across multiple files with their own symbol
882  * tables and string tables.
883  *
884  * Note that we do not obey list locking protocols here.  We really don't need
885  * DDB to hang because somebody's got the lock held.  We'll take the chance
886  * that the files list is inconsistant instead.
887  */
888 int
889 linker_ddb_lookup(const char *symstr, c_linker_sym_t *sym)
890 {
891 
892 	return (linker_debug_lookup(symstr, sym));
893 }
894 
895 int
896 linker_ddb_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
897 {
898 
899 	return (linker_debug_search_symbol(value, sym, diffp));
900 }
901 
902 int
903 linker_ddb_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
904 {
905 
906 	return (linker_debug_symbol_values(sym, symval));
907 }
908 
909 int
910 linker_ddb_search_symbol_name(caddr_t value, char *buf, u_int buflen,
911     long *offset)
912 {
913 
914 	return (linker_debug_search_symbol_name(value, buf, buflen, offset));
915 }
916 #endif
917 
918 /*
919  * stack(9) helper for non-debugging environemnts.  Unlike DDB helpers, we do
920  * obey locking protocols, and offer a significantly less complex interface.
921  */
922 int
923 linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
924     long *offset)
925 {
926 	int error;
927 
928 	KLD_LOCK();
929 	error = linker_debug_search_symbol_name(value, buf, buflen, offset);
930 	KLD_UNLOCK();
931 	return (error);
932 }
933 
934 /*
935  * Syscalls.
936  */
937 int
938 kern_kldload(struct thread *td, const char *file, int *fileid)
939 {
940 #ifdef HWPMC_HOOKS
941 	struct pmckern_map_in pkm;
942 #endif
943 	const char *kldname, *modname;
944 	linker_file_t lf;
945 	int error;
946 
947 	if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
948 		return (error);
949 
950 	if ((error = priv_check(td, PRIV_KLD_LOAD)) != 0)
951 		return (error);
952 
953 	/*
954 	 * If file does not contain a qualified name or any dot in it
955 	 * (kldname.ko, or kldname.ver.ko) treat it as an interface
956 	 * name.
957 	 */
958 	if (index(file, '/') || index(file, '.')) {
959 		kldname = file;
960 		modname = NULL;
961 	} else {
962 		kldname = NULL;
963 		modname = file;
964 	}
965 
966 	KLD_LOCK();
967 	error = linker_load_module(kldname, modname, NULL, NULL, &lf);
968 	if (error)
969 		goto unlock;
970 #ifdef HWPMC_HOOKS
971 	pkm.pm_file = lf->filename;
972 	pkm.pm_address = (uintptr_t) lf->address;
973 	PMC_CALL_HOOK(td, PMC_FN_KLD_LOAD, (void *) &pkm);
974 #endif
975 	lf->userrefs++;
976 	if (fileid != NULL)
977 		*fileid = lf->id;
978 unlock:
979 	KLD_UNLOCK();
980 	return (error);
981 }
982 
983 int
984 kldload(struct thread *td, struct kldload_args *uap)
985 {
986 	char *pathname = NULL;
987 	int error, fileid;
988 
989 	td->td_retval[0] = -1;
990 
991 	pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
992 	error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL);
993 	if (error == 0) {
994 		error = kern_kldload(td, pathname, &fileid);
995 		if (error == 0)
996 			td->td_retval[0] = fileid;
997 	}
998 	free(pathname, M_TEMP);
999 	return (error);
1000 }
1001 
1002 int
1003 kern_kldunload(struct thread *td, int fileid, int flags)
1004 {
1005 #ifdef HWPMC_HOOKS
1006 	struct pmckern_map_out pkm;
1007 #endif
1008 	linker_file_t lf;
1009 	int error = 0;
1010 
1011 	if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
1012 		return (error);
1013 
1014 	if ((error = priv_check(td, PRIV_KLD_UNLOAD)) != 0)
1015 		return (error);
1016 
1017 	KLD_LOCK();
1018 	lf = linker_find_file_by_id(fileid);
1019 	if (lf) {
1020 		KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
1021 
1022 		/* Check if there are DTrace probes enabled on this file. */
1023 		if (lf->nenabled > 0) {
1024 			printf("kldunload: attempt to unload file that has"
1025 			    " DTrace probes enabled\n");
1026 			error = EBUSY;
1027 		} else if (lf->userrefs == 0) {
1028 			/*
1029 			 * XXX: maybe LINKER_UNLOAD_FORCE should override ?
1030 			 */
1031 			printf("kldunload: attempt to unload file that was"
1032 			    " loaded by the kernel\n");
1033 			error = EBUSY;
1034 		} else {
1035 #ifdef HWPMC_HOOKS
1036 			/* Save data needed by hwpmc(4) before unloading. */
1037 			pkm.pm_address = (uintptr_t) lf->address;
1038 			pkm.pm_size = lf->size;
1039 #endif
1040 			lf->userrefs--;
1041 			error = linker_file_unload(lf, flags);
1042 			if (error)
1043 				lf->userrefs++;
1044 		}
1045 	} else
1046 		error = ENOENT;
1047 
1048 #ifdef HWPMC_HOOKS
1049 	if (error == 0)
1050 		PMC_CALL_HOOK(td, PMC_FN_KLD_UNLOAD, (void *) &pkm);
1051 #endif
1052 	KLD_UNLOCK();
1053 	return (error);
1054 }
1055 
1056 int
1057 kldunload(struct thread *td, struct kldunload_args *uap)
1058 {
1059 
1060 	return (kern_kldunload(td, uap->fileid, LINKER_UNLOAD_NORMAL));
1061 }
1062 
1063 int
1064 kldunloadf(struct thread *td, struct kldunloadf_args *uap)
1065 {
1066 
1067 	if (uap->flags != LINKER_UNLOAD_NORMAL &&
1068 	    uap->flags != LINKER_UNLOAD_FORCE)
1069 		return (EINVAL);
1070 	return (kern_kldunload(td, uap->fileid, uap->flags));
1071 }
1072 
1073 int
1074 kldfind(struct thread *td, struct kldfind_args *uap)
1075 {
1076 	char *pathname;
1077 	const char *filename;
1078 	linker_file_t lf;
1079 	int error;
1080 
1081 #ifdef MAC
1082 	error = mac_kld_check_stat(td->td_ucred);
1083 	if (error)
1084 		return (error);
1085 #endif
1086 
1087 	td->td_retval[0] = -1;
1088 
1089 	pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1090 	if ((error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL)) != 0)
1091 		goto out;
1092 
1093 	filename = linker_basename(pathname);
1094 	KLD_LOCK();
1095 	lf = linker_find_file_by_name(filename);
1096 	if (lf)
1097 		td->td_retval[0] = lf->id;
1098 	else
1099 		error = ENOENT;
1100 	KLD_UNLOCK();
1101 out:
1102 	free(pathname, M_TEMP);
1103 	return (error);
1104 }
1105 
1106 int
1107 kldnext(struct thread *td, struct kldnext_args *uap)
1108 {
1109 	linker_file_t lf;
1110 	int error = 0;
1111 
1112 #ifdef MAC
1113 	error = mac_kld_check_stat(td->td_ucred);
1114 	if (error)
1115 		return (error);
1116 #endif
1117 
1118 	KLD_LOCK();
1119 	if (uap->fileid == 0)
1120 		lf = TAILQ_FIRST(&linker_files);
1121 	else {
1122 		lf = linker_find_file_by_id(uap->fileid);
1123 		if (lf == NULL) {
1124 			error = ENOENT;
1125 			goto out;
1126 		}
1127 		lf = TAILQ_NEXT(lf, link);
1128 	}
1129 
1130 	/* Skip partially loaded files. */
1131 	while (lf != NULL && !(lf->flags & LINKER_FILE_LINKED))
1132 		lf = TAILQ_NEXT(lf, link);
1133 
1134 	if (lf)
1135 		td->td_retval[0] = lf->id;
1136 	else
1137 		td->td_retval[0] = 0;
1138 out:
1139 	KLD_UNLOCK();
1140 	return (error);
1141 }
1142 
1143 int
1144 kldstat(struct thread *td, struct kldstat_args *uap)
1145 {
1146 	struct kld_file_stat stat;
1147 	linker_file_t lf;
1148 	int error, namelen, version, version_num;
1149 
1150 	/*
1151 	 * Check the version of the user's structure.
1152 	 */
1153 	if ((error = copyin(&uap->stat->version, &version, sizeof(version))) != 0)
1154 		return (error);
1155 	if (version == sizeof(struct kld_file_stat_1))
1156 		version_num = 1;
1157 	else if (version == sizeof(struct kld_file_stat))
1158 		version_num = 2;
1159 	else
1160 		return (EINVAL);
1161 
1162 #ifdef MAC
1163 	error = mac_kld_check_stat(td->td_ucred);
1164 	if (error)
1165 		return (error);
1166 #endif
1167 
1168 	KLD_LOCK();
1169 	lf = linker_find_file_by_id(uap->fileid);
1170 	if (lf == NULL) {
1171 		KLD_UNLOCK();
1172 		return (ENOENT);
1173 	}
1174 
1175 	/* Version 1 fields: */
1176 	namelen = strlen(lf->filename) + 1;
1177 	if (namelen > MAXPATHLEN)
1178 		namelen = MAXPATHLEN;
1179 	bcopy(lf->filename, &stat.name[0], namelen);
1180 	stat.refs = lf->refs;
1181 	stat.id = lf->id;
1182 	stat.address = lf->address;
1183 	stat.size = lf->size;
1184 	if (version_num > 1) {
1185 		/* Version 2 fields: */
1186 		namelen = strlen(lf->pathname) + 1;
1187 		if (namelen > MAXPATHLEN)
1188 			namelen = MAXPATHLEN;
1189 		bcopy(lf->pathname, &stat.pathname[0], namelen);
1190 	}
1191 	KLD_UNLOCK();
1192 
1193 	td->td_retval[0] = 0;
1194 
1195 	return (copyout(&stat, uap->stat, version));
1196 }
1197 
1198 int
1199 kldfirstmod(struct thread *td, struct kldfirstmod_args *uap)
1200 {
1201 	linker_file_t lf;
1202 	module_t mp;
1203 	int error = 0;
1204 
1205 #ifdef MAC
1206 	error = mac_kld_check_stat(td->td_ucred);
1207 	if (error)
1208 		return (error);
1209 #endif
1210 
1211 	KLD_LOCK();
1212 	lf = linker_find_file_by_id(uap->fileid);
1213 	if (lf) {
1214 		MOD_SLOCK;
1215 		mp = TAILQ_FIRST(&lf->modules);
1216 		if (mp != NULL)
1217 			td->td_retval[0] = module_getid(mp);
1218 		else
1219 			td->td_retval[0] = 0;
1220 		MOD_SUNLOCK;
1221 	} else
1222 		error = ENOENT;
1223 	KLD_UNLOCK();
1224 	return (error);
1225 }
1226 
1227 int
1228 kldsym(struct thread *td, struct kldsym_args *uap)
1229 {
1230 	char *symstr = NULL;
1231 	c_linker_sym_t sym;
1232 	linker_symval_t symval;
1233 	linker_file_t lf;
1234 	struct kld_sym_lookup lookup;
1235 	int error = 0;
1236 
1237 #ifdef MAC
1238 	error = mac_kld_check_stat(td->td_ucred);
1239 	if (error)
1240 		return (error);
1241 #endif
1242 
1243 	if ((error = copyin(uap->data, &lookup, sizeof(lookup))) != 0)
1244 		return (error);
1245 	if (lookup.version != sizeof(lookup) ||
1246 	    uap->cmd != KLDSYM_LOOKUP)
1247 		return (EINVAL);
1248 	symstr = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1249 	if ((error = copyinstr(lookup.symname, symstr, MAXPATHLEN, NULL)) != 0)
1250 		goto out;
1251 	KLD_LOCK();
1252 	if (uap->fileid != 0) {
1253 		lf = linker_find_file_by_id(uap->fileid);
1254 		if (lf == NULL)
1255 			error = ENOENT;
1256 		else if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
1257 		    LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
1258 			lookup.symvalue = (uintptr_t) symval.value;
1259 			lookup.symsize = symval.size;
1260 			error = copyout(&lookup, uap->data, sizeof(lookup));
1261 		} else
1262 			error = ENOENT;
1263 	} else {
1264 		TAILQ_FOREACH(lf, &linker_files, link) {
1265 			if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
1266 			    LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
1267 				lookup.symvalue = (uintptr_t)symval.value;
1268 				lookup.symsize = symval.size;
1269 				error = copyout(&lookup, uap->data,
1270 				    sizeof(lookup));
1271 				break;
1272 			}
1273 		}
1274 		if (lf == NULL)
1275 			error = ENOENT;
1276 	}
1277 	KLD_UNLOCK();
1278 out:
1279 	free(symstr, M_TEMP);
1280 	return (error);
1281 }
1282 
1283 /*
1284  * Preloaded module support
1285  */
1286 
1287 static modlist_t
1288 modlist_lookup(const char *name, int ver)
1289 {
1290 	modlist_t mod;
1291 
1292 	TAILQ_FOREACH(mod, &found_modules, link) {
1293 		if (strcmp(mod->name, name) == 0 &&
1294 		    (ver == 0 || mod->version == ver))
1295 			return (mod);
1296 	}
1297 	return (NULL);
1298 }
1299 
1300 static modlist_t
1301 modlist_lookup2(const char *name, struct mod_depend *verinfo)
1302 {
1303 	modlist_t mod, bestmod;
1304 	int ver;
1305 
1306 	if (verinfo == NULL)
1307 		return (modlist_lookup(name, 0));
1308 	bestmod = NULL;
1309 	TAILQ_FOREACH(mod, &found_modules, link) {
1310 		if (strcmp(mod->name, name) != 0)
1311 			continue;
1312 		ver = mod->version;
1313 		if (ver == verinfo->md_ver_preferred)
1314 			return (mod);
1315 		if (ver >= verinfo->md_ver_minimum &&
1316 		    ver <= verinfo->md_ver_maximum &&
1317 		    (bestmod == NULL || ver > bestmod->version))
1318 			bestmod = mod;
1319 	}
1320 	return (bestmod);
1321 }
1322 
1323 static modlist_t
1324 modlist_newmodule(const char *modname, int version, linker_file_t container)
1325 {
1326 	modlist_t mod;
1327 
1328 	mod = malloc(sizeof(struct modlist), M_LINKER, M_NOWAIT | M_ZERO);
1329 	if (mod == NULL)
1330 		panic("no memory for module list");
1331 	mod->container = container;
1332 	mod->name = modname;
1333 	mod->version = version;
1334 	TAILQ_INSERT_TAIL(&found_modules, mod, link);
1335 	return (mod);
1336 }
1337 
1338 static void
1339 linker_addmodules(linker_file_t lf, struct mod_metadata **start,
1340     struct mod_metadata **stop, int preload)
1341 {
1342 	struct mod_metadata *mp, **mdp;
1343 	const char *modname;
1344 	int ver;
1345 
1346 	for (mdp = start; mdp < stop; mdp++) {
1347 		mp = *mdp;
1348 		if (mp->md_type != MDT_VERSION)
1349 			continue;
1350 		modname = mp->md_cval;
1351 		ver = ((struct mod_version *)mp->md_data)->mv_version;
1352 		if (modlist_lookup(modname, ver) != NULL) {
1353 			printf("module %s already present!\n", modname);
1354 			/* XXX what can we do? this is a build error. :-( */
1355 			continue;
1356 		}
1357 		modlist_newmodule(modname, ver, lf);
1358 	}
1359 }
1360 
1361 static void
1362 linker_preload(void *arg)
1363 {
1364 	caddr_t modptr;
1365 	const char *modname, *nmodname;
1366 	char *modtype;
1367 	linker_file_t lf, nlf;
1368 	linker_class_t lc;
1369 	int error;
1370 	linker_file_list_t loaded_files;
1371 	linker_file_list_t depended_files;
1372 	struct mod_metadata *mp, *nmp;
1373 	struct mod_metadata **start, **stop, **mdp, **nmdp;
1374 	struct mod_depend *verinfo;
1375 	int nver;
1376 	int resolves;
1377 	modlist_t mod;
1378 	struct sysinit **si_start, **si_stop;
1379 
1380 	TAILQ_INIT(&loaded_files);
1381 	TAILQ_INIT(&depended_files);
1382 	TAILQ_INIT(&found_modules);
1383 	error = 0;
1384 
1385 	modptr = NULL;
1386 	while ((modptr = preload_search_next_name(modptr)) != NULL) {
1387 		modname = (char *)preload_search_info(modptr, MODINFO_NAME);
1388 		modtype = (char *)preload_search_info(modptr, MODINFO_TYPE);
1389 		if (modname == NULL) {
1390 			printf("Preloaded module at %p does not have a"
1391 			    " name!\n", modptr);
1392 			continue;
1393 		}
1394 		if (modtype == NULL) {
1395 			printf("Preloaded module at %p does not have a type!\n",
1396 			    modptr);
1397 			continue;
1398 		}
1399 		if (bootverbose)
1400 			printf("Preloaded %s \"%s\" at %p.\n", modtype, modname,
1401 			    modptr);
1402 		lf = NULL;
1403 		TAILQ_FOREACH(lc, &classes, link) {
1404 			error = LINKER_LINK_PRELOAD(lc, modname, &lf);
1405 			if (!error)
1406 				break;
1407 			lf = NULL;
1408 		}
1409 		if (lf)
1410 			TAILQ_INSERT_TAIL(&loaded_files, lf, loaded);
1411 	}
1412 
1413 	/*
1414 	 * First get a list of stuff in the kernel.
1415 	 */
1416 	if (linker_file_lookup_set(linker_kernel_file, MDT_SETNAME, &start,
1417 	    &stop, NULL) == 0)
1418 		linker_addmodules(linker_kernel_file, start, stop, 1);
1419 
1420 	/*
1421 	 * This is a once-off kinky bubble sort to resolve relocation
1422 	 * dependency requirements.
1423 	 */
1424 restart:
1425 	TAILQ_FOREACH(lf, &loaded_files, loaded) {
1426 		error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
1427 		    &stop, NULL);
1428 		/*
1429 		 * First, look to see if we would successfully link with this
1430 		 * stuff.
1431 		 */
1432 		resolves = 1;	/* unless we know otherwise */
1433 		if (!error) {
1434 			for (mdp = start; mdp < stop; mdp++) {
1435 				mp = *mdp;
1436 				if (mp->md_type != MDT_DEPEND)
1437 					continue;
1438 				modname = mp->md_cval;
1439 				verinfo = mp->md_data;
1440 				for (nmdp = start; nmdp < stop; nmdp++) {
1441 					nmp = *nmdp;
1442 					if (nmp->md_type != MDT_VERSION)
1443 						continue;
1444 					nmodname = nmp->md_cval;
1445 					if (strcmp(modname, nmodname) == 0)
1446 						break;
1447 				}
1448 				if (nmdp < stop)   /* it's a self reference */
1449 					continue;
1450 
1451 				/*
1452 				 * ok, the module isn't here yet, we
1453 				 * are not finished
1454 				 */
1455 				if (modlist_lookup2(modname, verinfo) == NULL)
1456 					resolves = 0;
1457 			}
1458 		}
1459 		/*
1460 		 * OK, if we found our modules, we can link.  So, "provide"
1461 		 * the modules inside and add it to the end of the link order
1462 		 * list.
1463 		 */
1464 		if (resolves) {
1465 			if (!error) {
1466 				for (mdp = start; mdp < stop; mdp++) {
1467 					mp = *mdp;
1468 					if (mp->md_type != MDT_VERSION)
1469 						continue;
1470 					modname = mp->md_cval;
1471 					nver = ((struct mod_version *)
1472 					    mp->md_data)->mv_version;
1473 					if (modlist_lookup(modname,
1474 					    nver) != NULL) {
1475 						printf("module %s already"
1476 						    " present!\n", modname);
1477 						TAILQ_REMOVE(&loaded_files,
1478 						    lf, loaded);
1479 						linker_file_unload(lf,
1480 						    LINKER_UNLOAD_FORCE);
1481 						/* we changed tailq next ptr */
1482 						goto restart;
1483 					}
1484 					modlist_newmodule(modname, nver, lf);
1485 				}
1486 			}
1487 			TAILQ_REMOVE(&loaded_files, lf, loaded);
1488 			TAILQ_INSERT_TAIL(&depended_files, lf, loaded);
1489 			/*
1490 			 * Since we provided modules, we need to restart the
1491 			 * sort so that the previous files that depend on us
1492 			 * have a chance. Also, we've busted the tailq next
1493 			 * pointer with the REMOVE.
1494 			 */
1495 			goto restart;
1496 		}
1497 	}
1498 
1499 	/*
1500 	 * At this point, we check to see what could not be resolved..
1501 	 */
1502 	while ((lf = TAILQ_FIRST(&loaded_files)) != NULL) {
1503 		TAILQ_REMOVE(&loaded_files, lf, loaded);
1504 		printf("KLD file %s is missing dependencies\n", lf->filename);
1505 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1506 	}
1507 
1508 	/*
1509 	 * We made it. Finish off the linking in the order we determined.
1510 	 */
1511 	TAILQ_FOREACH_SAFE(lf, &depended_files, loaded, nlf) {
1512 		if (linker_kernel_file) {
1513 			linker_kernel_file->refs++;
1514 			error = linker_file_add_dependency(lf,
1515 			    linker_kernel_file);
1516 			if (error)
1517 				panic("cannot add dependency");
1518 		}
1519 		lf->userrefs++;	/* so we can (try to) kldunload it */
1520 		error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
1521 		    &stop, NULL);
1522 		if (!error) {
1523 			for (mdp = start; mdp < stop; mdp++) {
1524 				mp = *mdp;
1525 				if (mp->md_type != MDT_DEPEND)
1526 					continue;
1527 				modname = mp->md_cval;
1528 				verinfo = mp->md_data;
1529 				mod = modlist_lookup2(modname, verinfo);
1530 				/* Don't count self-dependencies */
1531 				if (lf == mod->container)
1532 					continue;
1533 				mod->container->refs++;
1534 				error = linker_file_add_dependency(lf,
1535 				    mod->container);
1536 				if (error)
1537 					panic("cannot add dependency");
1538 			}
1539 		}
1540 		/*
1541 		 * Now do relocation etc using the symbol search paths
1542 		 * established by the dependencies
1543 		 */
1544 		error = LINKER_LINK_PRELOAD_FINISH(lf);
1545 		if (error) {
1546 			TAILQ_REMOVE(&depended_files, lf, loaded);
1547 			printf("KLD file %s - could not finalize loading\n",
1548 			    lf->filename);
1549 			linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1550 			continue;
1551 		}
1552 		linker_file_register_modules(lf);
1553 		if (linker_file_lookup_set(lf, "sysinit_set", &si_start,
1554 		    &si_stop, NULL) == 0)
1555 			sysinit_add(si_start, si_stop);
1556 		linker_file_register_sysctls(lf);
1557 		lf->flags |= LINKER_FILE_LINKED;
1558 	}
1559 	/* woohoo! we made it! */
1560 }
1561 
1562 SYSINIT(preload, SI_SUB_KLD, SI_ORDER_MIDDLE, linker_preload, 0)
1563 
1564 /*
1565  * Search for a not-loaded module by name.
1566  *
1567  * Modules may be found in the following locations:
1568  *
1569  * - preloaded (result is just the module name) - on disk (result is full path
1570  * to module)
1571  *
1572  * If the module name is qualified in any way (contains path, etc.) the we
1573  * simply return a copy of it.
1574  *
1575  * The search path can be manipulated via sysctl.  Note that we use the ';'
1576  * character as a separator to be consistent with the bootloader.
1577  */
1578 
1579 static char linker_hintfile[] = "linker.hints";
1580 static char linker_path[MAXPATHLEN] = "/boot/kernel;/boot/modules";
1581 
1582 SYSCTL_STRING(_kern, OID_AUTO, module_path, CTLFLAG_RW, linker_path,
1583     sizeof(linker_path), "module load search path");
1584 
1585 TUNABLE_STR("module_path", linker_path, sizeof(linker_path));
1586 
1587 static char *linker_ext_list[] = {
1588 	"",
1589 	".ko",
1590 	NULL
1591 };
1592 
1593 /*
1594  * Check if file actually exists either with or without extension listed in
1595  * the linker_ext_list. (probably should be generic for the rest of the
1596  * kernel)
1597  */
1598 static char *
1599 linker_lookup_file(const char *path, int pathlen, const char *name,
1600     int namelen, struct vattr *vap)
1601 {
1602 	struct nameidata nd;
1603 	struct thread *td = curthread;	/* XXX */
1604 	char *result, **cpp, *sep;
1605 	int error, len, extlen, reclen, flags, vfslocked;
1606 	enum vtype type;
1607 
1608 	extlen = 0;
1609 	for (cpp = linker_ext_list; *cpp; cpp++) {
1610 		len = strlen(*cpp);
1611 		if (len > extlen)
1612 			extlen = len;
1613 	}
1614 	extlen++;		/* trailing '\0' */
1615 	sep = (path[pathlen - 1] != '/') ? "/" : "";
1616 
1617 	reclen = pathlen + strlen(sep) + namelen + extlen + 1;
1618 	result = malloc(reclen, M_LINKER, M_WAITOK);
1619 	for (cpp = linker_ext_list; *cpp; cpp++) {
1620 		snprintf(result, reclen, "%.*s%s%.*s%s", pathlen, path, sep,
1621 		    namelen, name, *cpp);
1622 		/*
1623 		 * Attempt to open the file, and return the path if
1624 		 * we succeed and it's a regular file.
1625 		 */
1626 		NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, result, td);
1627 		flags = FREAD;
1628 		error = vn_open(&nd, &flags, 0, NULL);
1629 		if (error == 0) {
1630 			vfslocked = NDHASGIANT(&nd);
1631 			NDFREE(&nd, NDF_ONLY_PNBUF);
1632 			type = nd.ni_vp->v_type;
1633 			if (vap)
1634 				VOP_GETATTR(nd.ni_vp, vap, td->td_ucred, td);
1635 			VOP_UNLOCK(nd.ni_vp, 0);
1636 			vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1637 			VFS_UNLOCK_GIANT(vfslocked);
1638 			if (type == VREG)
1639 				return (result);
1640 		}
1641 	}
1642 	free(result, M_LINKER);
1643 	return (NULL);
1644 }
1645 
1646 #define	INT_ALIGN(base, ptr)	ptr =					\
1647 	(base) + (((ptr) - (base) + sizeof(int) - 1) & ~(sizeof(int) - 1))
1648 
1649 /*
1650  * Lookup KLD which contains requested module in the "linker.hints" file. If
1651  * version specification is available, then try to find the best KLD.
1652  * Otherwise just find the latest one.
1653  */
1654 static char *
1655 linker_hints_lookup(const char *path, int pathlen, const char *modname,
1656     int modnamelen, struct mod_depend *verinfo)
1657 {
1658 	struct thread *td = curthread;	/* XXX */
1659 	struct ucred *cred = td ? td->td_ucred : NULL;
1660 	struct nameidata nd;
1661 	struct vattr vattr, mattr;
1662 	u_char *hints = NULL;
1663 	u_char *cp, *recptr, *bufend, *result, *best, *pathbuf, *sep;
1664 	int error, ival, bestver, *intp, reclen, found, flags, clen, blen;
1665 	int vfslocked = 0;
1666 
1667 	result = NULL;
1668 	bestver = found = 0;
1669 
1670 	sep = (path[pathlen - 1] != '/') ? "/" : "";
1671 	reclen = imax(modnamelen, strlen(linker_hintfile)) + pathlen +
1672 	    strlen(sep) + 1;
1673 	pathbuf = malloc(reclen, M_LINKER, M_WAITOK);
1674 	snprintf(pathbuf, reclen, "%.*s%s%s", pathlen, path, sep,
1675 	    linker_hintfile);
1676 
1677 	NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE, UIO_SYSSPACE, pathbuf, td);
1678 	flags = FREAD;
1679 	error = vn_open(&nd, &flags, 0, NULL);
1680 	if (error)
1681 		goto bad;
1682 	vfslocked = NDHASGIANT(&nd);
1683 	NDFREE(&nd, NDF_ONLY_PNBUF);
1684 	if (nd.ni_vp->v_type != VREG)
1685 		goto bad;
1686 	best = cp = NULL;
1687 	error = VOP_GETATTR(nd.ni_vp, &vattr, cred, td);
1688 	if (error)
1689 		goto bad;
1690 	/*
1691 	 * XXX: we need to limit this number to some reasonable value
1692 	 */
1693 	if (vattr.va_size > 100 * 1024) {
1694 		printf("hints file too large %ld\n", (long)vattr.va_size);
1695 		goto bad;
1696 	}
1697 	hints = malloc(vattr.va_size, M_TEMP, M_WAITOK);
1698 	if (hints == NULL)
1699 		goto bad;
1700 	error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)hints, vattr.va_size, 0,
1701 	    UIO_SYSSPACE, IO_NODELOCKED, cred, NOCRED, &reclen, td);
1702 	if (error)
1703 		goto bad;
1704 	VOP_UNLOCK(nd.ni_vp, 0);
1705 	vn_close(nd.ni_vp, FREAD, cred, td);
1706 	VFS_UNLOCK_GIANT(vfslocked);
1707 	nd.ni_vp = NULL;
1708 	if (reclen != 0) {
1709 		printf("can't read %d\n", reclen);
1710 		goto bad;
1711 	}
1712 	intp = (int *)hints;
1713 	ival = *intp++;
1714 	if (ival != LINKER_HINTS_VERSION) {
1715 		printf("hints file version mismatch %d\n", ival);
1716 		goto bad;
1717 	}
1718 	bufend = hints + vattr.va_size;
1719 	recptr = (u_char *)intp;
1720 	clen = blen = 0;
1721 	while (recptr < bufend && !found) {
1722 		intp = (int *)recptr;
1723 		reclen = *intp++;
1724 		ival = *intp++;
1725 		cp = (char *)intp;
1726 		switch (ival) {
1727 		case MDT_VERSION:
1728 			clen = *cp++;
1729 			if (clen != modnamelen || bcmp(cp, modname, clen) != 0)
1730 				break;
1731 			cp += clen;
1732 			INT_ALIGN(hints, cp);
1733 			ival = *(int *)cp;
1734 			cp += sizeof(int);
1735 			clen = *cp++;
1736 			if (verinfo == NULL ||
1737 			    ival == verinfo->md_ver_preferred) {
1738 				found = 1;
1739 				break;
1740 			}
1741 			if (ival >= verinfo->md_ver_minimum &&
1742 			    ival <= verinfo->md_ver_maximum &&
1743 			    ival > bestver) {
1744 				bestver = ival;
1745 				best = cp;
1746 				blen = clen;
1747 			}
1748 			break;
1749 		default:
1750 			break;
1751 		}
1752 		recptr += reclen + sizeof(int);
1753 	}
1754 	/*
1755 	 * Finally check if KLD is in the place
1756 	 */
1757 	if (found)
1758 		result = linker_lookup_file(path, pathlen, cp, clen, &mattr);
1759 	else if (best)
1760 		result = linker_lookup_file(path, pathlen, best, blen, &mattr);
1761 
1762 	/*
1763 	 * KLD is newer than hints file. What we should do now?
1764 	 */
1765 	if (result && timespeccmp(&mattr.va_mtime, &vattr.va_mtime, >))
1766 		printf("warning: KLD '%s' is newer than the linker.hints"
1767 		    " file\n", result);
1768 bad:
1769 	free(pathbuf, M_LINKER);
1770 	if (hints)
1771 		free(hints, M_TEMP);
1772 	if (nd.ni_vp != NULL) {
1773 		VOP_UNLOCK(nd.ni_vp, 0);
1774 		vn_close(nd.ni_vp, FREAD, cred, td);
1775 		VFS_UNLOCK_GIANT(vfslocked);
1776 	}
1777 	/*
1778 	 * If nothing found or hints is absent - fallback to the old
1779 	 * way by using "kldname[.ko]" as module name.
1780 	 */
1781 	if (!found && !bestver && result == NULL)
1782 		result = linker_lookup_file(path, pathlen, modname,
1783 		    modnamelen, NULL);
1784 	return (result);
1785 }
1786 
1787 /*
1788  * Lookup KLD which contains requested module in the all directories.
1789  */
1790 static char *
1791 linker_search_module(const char *modname, int modnamelen,
1792     struct mod_depend *verinfo)
1793 {
1794 	char *cp, *ep, *result;
1795 
1796 	/*
1797 	 * traverse the linker path
1798 	 */
1799 	for (cp = linker_path; *cp; cp = ep + 1) {
1800 		/* find the end of this component */
1801 		for (ep = cp; (*ep != 0) && (*ep != ';'); ep++);
1802 		result = linker_hints_lookup(cp, ep - cp, modname,
1803 		    modnamelen, verinfo);
1804 		if (result != NULL)
1805 			return (result);
1806 		if (*ep == 0)
1807 			break;
1808 	}
1809 	return (NULL);
1810 }
1811 
1812 /*
1813  * Search for module in all directories listed in the linker_path.
1814  */
1815 static char *
1816 linker_search_kld(const char *name)
1817 {
1818 	char *cp, *ep, *result;
1819 	int len;
1820 
1821 	/* qualified at all? */
1822 	if (index(name, '/'))
1823 		return (linker_strdup(name));
1824 
1825 	/* traverse the linker path */
1826 	len = strlen(name);
1827 	for (ep = linker_path; *ep; ep++) {
1828 		cp = ep;
1829 		/* find the end of this component */
1830 		for (; *ep != 0 && *ep != ';'; ep++);
1831 		result = linker_lookup_file(cp, ep - cp, name, len, NULL);
1832 		if (result != NULL)
1833 			return (result);
1834 	}
1835 	return (NULL);
1836 }
1837 
1838 static const char *
1839 linker_basename(const char *path)
1840 {
1841 	const char *filename;
1842 
1843 	filename = rindex(path, '/');
1844 	if (filename == NULL)
1845 		return path;
1846 	if (filename[1])
1847 		filename++;
1848 	return (filename);
1849 }
1850 
1851 #ifdef HWPMC_HOOKS
1852 
1853 struct hwpmc_context {
1854 	int	nobjects;
1855 	int	nmappings;
1856 	struct pmckern_map_in *kobase;
1857 };
1858 
1859 static int
1860 linker_hwpmc_list_object(linker_file_t lf, void *arg)
1861 {
1862 	struct hwpmc_context *hc;
1863 
1864 	hc = arg;
1865 
1866 	/* If we run out of mappings, fail. */
1867 	if (hc->nobjects >= hc->nmappings)
1868 		return (1);
1869 
1870 	/* Save the info for this linker file. */
1871 	hc->kobase[hc->nobjects].pm_file = lf->filename;
1872 	hc->kobase[hc->nobjects].pm_address = (uintptr_t)lf->address;
1873 	hc->nobjects++;
1874 	return (0);
1875 }
1876 
1877 /*
1878  * Inform hwpmc about the set of kernel modules currently loaded.
1879  */
1880 void *
1881 linker_hwpmc_list_objects(void)
1882 {
1883 	struct hwpmc_context hc;
1884 
1885 	hc.nmappings = 15;	/* a reasonable default */
1886 
1887  retry:
1888 	/* allocate nmappings+1 entries */
1889 	MALLOC(hc.kobase, struct pmckern_map_in *,
1890 	    (hc.nmappings + 1) * sizeof(struct pmckern_map_in), M_LINKER,
1891 	    M_WAITOK | M_ZERO);
1892 
1893 	hc.nobjects = 0;
1894 	if (linker_file_foreach(linker_hwpmc_list_object, &hc) != 0) {
1895 		hc.nmappings = hc.nobjects;
1896 		FREE(hc.kobase, M_LINKER);
1897 		goto retry;
1898 	}
1899 
1900 	KASSERT(hc.nobjects > 0, ("linker_hpwmc_list_objects: no kernel "
1901 		"objects?"));
1902 
1903 	/* The last entry of the malloced area comprises of all zeros. */
1904 	KASSERT(hc.kobase[hc.nobjects].pm_file == NULL,
1905 	    ("linker_hwpmc_list_objects: last object not NULL"));
1906 
1907 	return ((void *)hc.kobase);
1908 }
1909 #endif
1910 
1911 /*
1912  * Find a file which contains given module and load it, if "parent" is not
1913  * NULL, register a reference to it.
1914  */
1915 static int
1916 linker_load_module(const char *kldname, const char *modname,
1917     struct linker_file *parent, struct mod_depend *verinfo,
1918     struct linker_file **lfpp)
1919 {
1920 	linker_file_t lfdep;
1921 	const char *filename;
1922 	char *pathname;
1923 	int error;
1924 
1925 	KLD_LOCK_ASSERT();
1926 	if (modname == NULL) {
1927 		/*
1928  		 * We have to load KLD
1929  		 */
1930 		KASSERT(verinfo == NULL, ("linker_load_module: verinfo"
1931 		    " is not NULL"));
1932 		pathname = linker_search_kld(kldname);
1933 	} else {
1934 		if (modlist_lookup2(modname, verinfo) != NULL)
1935 			return (EEXIST);
1936 		if (kldname != NULL)
1937 			pathname = linker_strdup(kldname);
1938 		else if (rootvnode == NULL)
1939 			pathname = NULL;
1940 		else
1941 			/*
1942 			 * Need to find a KLD with required module
1943 			 */
1944 			pathname = linker_search_module(modname,
1945 			    strlen(modname), verinfo);
1946 	}
1947 	if (pathname == NULL)
1948 		return (ENOENT);
1949 
1950 	/*
1951 	 * Can't load more than one file with the same basename XXX:
1952 	 * Actually it should be possible to have multiple KLDs with
1953 	 * the same basename but different path because they can
1954 	 * provide different versions of the same modules.
1955 	 */
1956 	filename = linker_basename(pathname);
1957 	if (linker_find_file_by_name(filename))
1958 		error = EEXIST;
1959 	else do {
1960 		error = linker_load_file(pathname, &lfdep);
1961 		if (error)
1962 			break;
1963 		if (modname && verinfo &&
1964 		    modlist_lookup2(modname, verinfo) == NULL) {
1965 			linker_file_unload(lfdep, LINKER_UNLOAD_FORCE);
1966 			error = ENOENT;
1967 			break;
1968 		}
1969 		if (parent) {
1970 			error = linker_file_add_dependency(parent, lfdep);
1971 			if (error)
1972 				break;
1973 		}
1974 		if (lfpp)
1975 			*lfpp = lfdep;
1976 	} while (0);
1977 	free(pathname, M_LINKER);
1978 	return (error);
1979 }
1980 
1981 /*
1982  * This routine is responsible for finding dependencies of userland initiated
1983  * kldload(2)'s of files.
1984  */
1985 int
1986 linker_load_dependencies(linker_file_t lf)
1987 {
1988 	linker_file_t lfdep;
1989 	struct mod_metadata **start, **stop, **mdp, **nmdp;
1990 	struct mod_metadata *mp, *nmp;
1991 	struct mod_depend *verinfo;
1992 	modlist_t mod;
1993 	const char *modname, *nmodname;
1994 	int ver, error = 0, count;
1995 
1996 	/*
1997 	 * All files are dependant on /kernel.
1998 	 */
1999 	KLD_LOCK_ASSERT();
2000 	if (linker_kernel_file) {
2001 		linker_kernel_file->refs++;
2002 		error = linker_file_add_dependency(lf, linker_kernel_file);
2003 		if (error)
2004 			return (error);
2005 	}
2006 	if (linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop,
2007 	    &count) != 0)
2008 		return (0);
2009 	for (mdp = start; mdp < stop; mdp++) {
2010 		mp = *mdp;
2011 		if (mp->md_type != MDT_VERSION)
2012 			continue;
2013 		modname = mp->md_cval;
2014 		ver = ((struct mod_version *)mp->md_data)->mv_version;
2015 		mod = modlist_lookup(modname, ver);
2016 		if (mod != NULL) {
2017 			printf("interface %s.%d already present in the KLD"
2018 			    " '%s'!\n", modname, ver,
2019 			    mod->container->filename);
2020 			return (EEXIST);
2021 		}
2022 	}
2023 
2024 	for (mdp = start; mdp < stop; mdp++) {
2025 		mp = *mdp;
2026 		if (mp->md_type != MDT_DEPEND)
2027 			continue;
2028 		modname = mp->md_cval;
2029 		verinfo = mp->md_data;
2030 		nmodname = NULL;
2031 		for (nmdp = start; nmdp < stop; nmdp++) {
2032 			nmp = *nmdp;
2033 			if (nmp->md_type != MDT_VERSION)
2034 				continue;
2035 			nmodname = nmp->md_cval;
2036 			if (strcmp(modname, nmodname) == 0)
2037 				break;
2038 		}
2039 		if (nmdp < stop)/* early exit, it's a self reference */
2040 			continue;
2041 		mod = modlist_lookup2(modname, verinfo);
2042 		if (mod) {	/* woohoo, it's loaded already */
2043 			lfdep = mod->container;
2044 			lfdep->refs++;
2045 			error = linker_file_add_dependency(lf, lfdep);
2046 			if (error)
2047 				break;
2048 			continue;
2049 		}
2050 		error = linker_load_module(NULL, modname, lf, verinfo, NULL);
2051 		if (error) {
2052 			printf("KLD %s: depends on %s - not available\n",
2053 			    lf->filename, modname);
2054 			break;
2055 		}
2056 	}
2057 
2058 	if (error)
2059 		return (error);
2060 	linker_addmodules(lf, start, stop, 0);
2061 	return (error);
2062 }
2063 
2064 static int
2065 sysctl_kern_function_list_iterate(const char *name, void *opaque)
2066 {
2067 	struct sysctl_req *req;
2068 
2069 	req = opaque;
2070 	return (SYSCTL_OUT(req, name, strlen(name) + 1));
2071 }
2072 
2073 /*
2074  * Export a nul-separated, double-nul-terminated list of all function names
2075  * in the kernel.
2076  */
2077 static int
2078 sysctl_kern_function_list(SYSCTL_HANDLER_ARGS)
2079 {
2080 	linker_file_t lf;
2081 	int error;
2082 
2083 #ifdef MAC
2084 	error = mac_kld_check_stat(req->td->td_ucred);
2085 	if (error)
2086 		return (error);
2087 #endif
2088 	error = sysctl_wire_old_buffer(req, 0);
2089 	if (error != 0)
2090 		return (error);
2091 	KLD_LOCK();
2092 	TAILQ_FOREACH(lf, &linker_files, link) {
2093 		error = LINKER_EACH_FUNCTION_NAME(lf,
2094 		    sysctl_kern_function_list_iterate, req);
2095 		if (error) {
2096 			KLD_UNLOCK();
2097 			return (error);
2098 		}
2099 	}
2100 	KLD_UNLOCK();
2101 	return (SYSCTL_OUT(req, "", 1));
2102 }
2103 
2104 SYSCTL_PROC(_kern, OID_AUTO, function_list, CTLFLAG_RD,
2105     NULL, 0, sysctl_kern_function_list, "", "kernel function list");
2106