xref: /freebsd/sys/kern/kern_linker.c (revision 3c5ba95ad12285ad37c182a4bfc1b240ec6d18a7)
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 	STAILQ_INIT(&lf->common);
628 	TAILQ_INIT(&lf->modules);
629 	TAILQ_INSERT_TAIL(&linker_files, lf, link);
630 	return (lf);
631 }
632 
633 int
634 linker_file_unload(linker_file_t file, int flags)
635 {
636 	module_t mod, next;
637 	modlist_t ml, nextml;
638 	struct common_symbol *cp;
639 	int error, i;
640 
641 	/* Refuse to unload modules if securelevel raised. */
642 	if (prison0.pr_securelevel > 0)
643 		return (EPERM);
644 
645 	sx_assert(&kld_sx, SA_XLOCKED);
646 	KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
647 
648 	/* Easy case of just dropping a reference. */
649 	if (file->refs > 1) {
650 		file->refs--;
651 		return (0);
652 	}
653 
654 	/* Give eventhandlers a chance to prevent the unload. */
655 	error = 0;
656 	EVENTHANDLER_INVOKE(kld_unload_try, file, &error);
657 	if (error != 0)
658 		return (EBUSY);
659 
660 	KLD_DPF(FILE, ("linker_file_unload: file is unloading,"
661 	    " informing modules\n"));
662 
663 	/*
664 	 * Quiesce all the modules to give them a chance to veto the unload.
665 	 */
666 	MOD_SLOCK;
667 	for (mod = TAILQ_FIRST(&file->modules); mod;
668 	     mod = module_getfnext(mod)) {
669 
670 		error = module_quiesce(mod);
671 		if (error != 0 && flags != LINKER_UNLOAD_FORCE) {
672 			KLD_DPF(FILE, ("linker_file_unload: module %s"
673 			    " vetoed unload\n", module_getname(mod)));
674 			/*
675 			 * XXX: Do we need to tell all the quiesced modules
676 			 * that they can resume work now via a new module
677 			 * event?
678 			 */
679 			MOD_SUNLOCK;
680 			return (error);
681 		}
682 	}
683 	MOD_SUNLOCK;
684 
685 	/*
686 	 * Inform any modules associated with this file that they are
687 	 * being unloaded.
688 	 */
689 	MOD_XLOCK;
690 	for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
691 		next = module_getfnext(mod);
692 		MOD_XUNLOCK;
693 
694 		/*
695 		 * Give the module a chance to veto the unload.
696 		 */
697 		if ((error = module_unload(mod)) != 0) {
698 #ifdef KLD_DEBUG
699 			MOD_SLOCK;
700 			KLD_DPF(FILE, ("linker_file_unload: module %s"
701 			    " failed unload\n", module_getname(mod)));
702 			MOD_SUNLOCK;
703 #endif
704 			return (error);
705 		}
706 		MOD_XLOCK;
707 		module_release(mod);
708 	}
709 	MOD_XUNLOCK;
710 
711 	TAILQ_FOREACH_SAFE(ml, &found_modules, link, nextml) {
712 		if (ml->container == file) {
713 			TAILQ_REMOVE(&found_modules, ml, link);
714 			free(ml, M_LINKER);
715 		}
716 	}
717 
718 	/*
719 	 * Don't try to run SYSUNINITs if we are unloaded due to a
720 	 * link error.
721 	 */
722 	if (file->flags & LINKER_FILE_LINKED) {
723 		file->flags &= ~LINKER_FILE_LINKED;
724 		linker_file_unregister_sysctls(file);
725 		linker_file_sysuninit(file);
726 	}
727 	TAILQ_REMOVE(&linker_files, file, link);
728 
729 	if (file->deps) {
730 		for (i = 0; i < file->ndeps; i++)
731 			linker_file_unload(file->deps[i], flags);
732 		free(file->deps, M_LINKER);
733 		file->deps = NULL;
734 	}
735 	while ((cp = STAILQ_FIRST(&file->common)) != NULL) {
736 		STAILQ_REMOVE_HEAD(&file->common, link);
737 		free(cp, M_LINKER);
738 	}
739 
740 	LINKER_UNLOAD(file);
741 
742 	EVENTHANDLER_INVOKE(kld_unload, file->filename, file->address,
743 	    file->size);
744 
745 	if (file->filename) {
746 		free(file->filename, M_LINKER);
747 		file->filename = NULL;
748 	}
749 	if (file->pathname) {
750 		free(file->pathname, M_LINKER);
751 		file->pathname = NULL;
752 	}
753 	kobj_delete((kobj_t) file, M_LINKER);
754 	return (0);
755 }
756 
757 int
758 linker_ctf_get(linker_file_t file, linker_ctf_t *lc)
759 {
760 	return (LINKER_CTF_GET(file, lc));
761 }
762 
763 static int
764 linker_file_add_dependency(linker_file_t file, linker_file_t dep)
765 {
766 	linker_file_t *newdeps;
767 
768 	sx_assert(&kld_sx, SA_XLOCKED);
769 	file->deps = realloc(file->deps, (file->ndeps + 1) * sizeof(*newdeps),
770 	    M_LINKER, M_WAITOK | M_ZERO);
771 	file->deps[file->ndeps] = dep;
772 	file->ndeps++;
773 	KLD_DPF(FILE, ("linker_file_add_dependency:"
774 	    " adding %s as dependency for %s\n",
775 	    dep->filename, file->filename));
776 	return (0);
777 }
778 
779 /*
780  * Locate a linker set and its contents.  This is a helper function to avoid
781  * linker_if.h exposure elsewhere.  Note: firstp and lastp are really void **.
782  * This function is used in this file so we can avoid having lots of (void **)
783  * casts.
784  */
785 int
786 linker_file_lookup_set(linker_file_t file, const char *name,
787     void *firstp, void *lastp, int *countp)
788 {
789 
790 	sx_assert(&kld_sx, SA_LOCKED);
791 	return (LINKER_LOOKUP_SET(file, name, firstp, lastp, countp));
792 }
793 
794 /*
795  * List all functions in a file.
796  */
797 int
798 linker_file_function_listall(linker_file_t lf,
799     linker_function_nameval_callback_t callback_func, void *arg)
800 {
801 	return (LINKER_EACH_FUNCTION_NAMEVAL(lf, callback_func, arg));
802 }
803 
804 caddr_t
805 linker_file_lookup_symbol(linker_file_t file, const char *name, int deps)
806 {
807 	caddr_t sym;
808 	int locked;
809 
810 	locked = sx_xlocked(&kld_sx);
811 	if (!locked)
812 		sx_xlock(&kld_sx);
813 	sym = linker_file_lookup_symbol_internal(file, name, deps);
814 	if (!locked)
815 		sx_xunlock(&kld_sx);
816 	return (sym);
817 }
818 
819 static caddr_t
820 linker_file_lookup_symbol_internal(linker_file_t file, const char *name,
821     int deps)
822 {
823 	c_linker_sym_t sym;
824 	linker_symval_t symval;
825 	caddr_t address;
826 	size_t common_size = 0;
827 	int i;
828 
829 	sx_assert(&kld_sx, SA_XLOCKED);
830 	KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n",
831 	    file, name, deps));
832 
833 	if (LINKER_LOOKUP_SYMBOL(file, name, &sym) == 0) {
834 		LINKER_SYMBOL_VALUES(file, sym, &symval);
835 		if (symval.value == 0)
836 			/*
837 			 * For commons, first look them up in the
838 			 * dependencies and only allocate space if not found
839 			 * there.
840 			 */
841 			common_size = symval.size;
842 		else {
843 			KLD_DPF(SYM, ("linker_file_lookup_symbol: symbol"
844 			    ".value=%p\n", symval.value));
845 			return (symval.value);
846 		}
847 	}
848 	if (deps) {
849 		for (i = 0; i < file->ndeps; i++) {
850 			address = linker_file_lookup_symbol_internal(
851 			    file->deps[i], name, 0);
852 			if (address) {
853 				KLD_DPF(SYM, ("linker_file_lookup_symbol:"
854 				    " deps value=%p\n", address));
855 				return (address);
856 			}
857 		}
858 	}
859 	if (common_size > 0) {
860 		/*
861 		 * This is a common symbol which was not found in the
862 		 * dependencies.  We maintain a simple common symbol table in
863 		 * the file object.
864 		 */
865 		struct common_symbol *cp;
866 
867 		STAILQ_FOREACH(cp, &file->common, link) {
868 			if (strcmp(cp->name, name) == 0) {
869 				KLD_DPF(SYM, ("linker_file_lookup_symbol:"
870 				    " old common value=%p\n", cp->address));
871 				return (cp->address);
872 			}
873 		}
874 		/*
875 		 * Round the symbol size up to align.
876 		 */
877 		common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
878 		cp = malloc(sizeof(struct common_symbol)
879 		    + common_size + strlen(name) + 1, M_LINKER,
880 		    M_WAITOK | M_ZERO);
881 		cp->address = (caddr_t)(cp + 1);
882 		cp->name = cp->address + common_size;
883 		strcpy(cp->name, name);
884 		bzero(cp->address, common_size);
885 		STAILQ_INSERT_TAIL(&file->common, cp, link);
886 
887 		KLD_DPF(SYM, ("linker_file_lookup_symbol: new common"
888 		    " value=%p\n", cp->address));
889 		return (cp->address);
890 	}
891 	KLD_DPF(SYM, ("linker_file_lookup_symbol: fail\n"));
892 	return (0);
893 }
894 
895 /*
896  * Both DDB and stack(9) rely on the kernel linker to provide forward and
897  * backward lookup of symbols.  However, DDB and sometimes stack(9) need to
898  * do this in a lockfree manner.  We provide a set of internal helper
899  * routines to perform these operations without locks, and then wrappers that
900  * optionally lock.
901  *
902  * linker_debug_lookup() is ifdef DDB as currently it's only used by DDB.
903  */
904 #ifdef DDB
905 static int
906 linker_debug_lookup(const char *symstr, c_linker_sym_t *sym)
907 {
908 	linker_file_t lf;
909 
910 	TAILQ_FOREACH(lf, &linker_files, link) {
911 		if (LINKER_LOOKUP_SYMBOL(lf, symstr, sym) == 0)
912 			return (0);
913 	}
914 	return (ENOENT);
915 }
916 #endif
917 
918 static int
919 linker_debug_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
920 {
921 	linker_file_t lf;
922 	c_linker_sym_t best, es;
923 	u_long diff, bestdiff, off;
924 
925 	best = 0;
926 	off = (uintptr_t)value;
927 	bestdiff = off;
928 	TAILQ_FOREACH(lf, &linker_files, link) {
929 		if (LINKER_SEARCH_SYMBOL(lf, value, &es, &diff) != 0)
930 			continue;
931 		if (es != 0 && diff < bestdiff) {
932 			best = es;
933 			bestdiff = diff;
934 		}
935 		if (bestdiff == 0)
936 			break;
937 	}
938 	if (best) {
939 		*sym = best;
940 		*diffp = bestdiff;
941 		return (0);
942 	} else {
943 		*sym = 0;
944 		*diffp = off;
945 		return (ENOENT);
946 	}
947 }
948 
949 static int
950 linker_debug_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
951 {
952 	linker_file_t lf;
953 
954 	TAILQ_FOREACH(lf, &linker_files, link) {
955 		if (LINKER_SYMBOL_VALUES(lf, sym, symval) == 0)
956 			return (0);
957 	}
958 	return (ENOENT);
959 }
960 
961 static int
962 linker_debug_search_symbol_name(caddr_t value, char *buf, u_int buflen,
963     long *offset)
964 {
965 	linker_symval_t symval;
966 	c_linker_sym_t sym;
967 	int error;
968 
969 	*offset = 0;
970 	error = linker_debug_search_symbol(value, &sym, offset);
971 	if (error)
972 		return (error);
973 	error = linker_debug_symbol_values(sym, &symval);
974 	if (error)
975 		return (error);
976 	strlcpy(buf, symval.name, buflen);
977 	return (0);
978 }
979 
980 /*
981  * DDB Helpers.  DDB has to look across multiple files with their own symbol
982  * tables and string tables.
983  *
984  * Note that we do not obey list locking protocols here.  We really don't need
985  * DDB to hang because somebody's got the lock held.  We'll take the chance
986  * that the files list is inconsistent instead.
987  */
988 #ifdef DDB
989 int
990 linker_ddb_lookup(const char *symstr, c_linker_sym_t *sym)
991 {
992 
993 	return (linker_debug_lookup(symstr, sym));
994 }
995 #endif
996 
997 int
998 linker_ddb_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
999 {
1000 
1001 	return (linker_debug_search_symbol(value, sym, diffp));
1002 }
1003 
1004 int
1005 linker_ddb_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
1006 {
1007 
1008 	return (linker_debug_symbol_values(sym, symval));
1009 }
1010 
1011 int
1012 linker_ddb_search_symbol_name(caddr_t value, char *buf, u_int buflen,
1013     long *offset)
1014 {
1015 
1016 	return (linker_debug_search_symbol_name(value, buf, buflen, offset));
1017 }
1018 
1019 /*
1020  * stack(9) helper for non-debugging environemnts.  Unlike DDB helpers, we do
1021  * obey locking protocols, and offer a significantly less complex interface.
1022  */
1023 int
1024 linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
1025     long *offset)
1026 {
1027 	int error;
1028 
1029 	sx_slock(&kld_sx);
1030 	error = linker_debug_search_symbol_name(value, buf, buflen, offset);
1031 	sx_sunlock(&kld_sx);
1032 	return (error);
1033 }
1034 
1035 /*
1036  * Syscalls.
1037  */
1038 int
1039 kern_kldload(struct thread *td, const char *file, int *fileid)
1040 {
1041 	const char *kldname, *modname;
1042 	linker_file_t lf;
1043 	int error;
1044 
1045 	if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
1046 		return (error);
1047 
1048 	if ((error = priv_check(td, PRIV_KLD_LOAD)) != 0)
1049 		return (error);
1050 
1051 	/*
1052 	 * It is possible that kldloaded module will attach a new ifnet,
1053 	 * so vnet context must be set when this ocurs.
1054 	 */
1055 	CURVNET_SET(TD_TO_VNET(td));
1056 
1057 	/*
1058 	 * If file does not contain a qualified name or any dot in it
1059 	 * (kldname.ko, or kldname.ver.ko) treat it as an interface
1060 	 * name.
1061 	 */
1062 	if (strchr(file, '/') || strchr(file, '.')) {
1063 		kldname = file;
1064 		modname = NULL;
1065 	} else {
1066 		kldname = NULL;
1067 		modname = file;
1068 	}
1069 
1070 	sx_xlock(&kld_sx);
1071 	error = linker_load_module(kldname, modname, NULL, NULL, &lf);
1072 	if (error) {
1073 		sx_xunlock(&kld_sx);
1074 		goto done;
1075 	}
1076 	lf->userrefs++;
1077 	if (fileid != NULL)
1078 		*fileid = lf->id;
1079 	sx_xunlock(&kld_sx);
1080 
1081 done:
1082 	CURVNET_RESTORE();
1083 	return (error);
1084 }
1085 
1086 int
1087 sys_kldload(struct thread *td, struct kldload_args *uap)
1088 {
1089 	char *pathname = NULL;
1090 	int error, fileid;
1091 
1092 	td->td_retval[0] = -1;
1093 
1094 	pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1095 	error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL);
1096 	if (error == 0) {
1097 		error = kern_kldload(td, pathname, &fileid);
1098 		if (error == 0)
1099 			td->td_retval[0] = fileid;
1100 	}
1101 	free(pathname, M_TEMP);
1102 	return (error);
1103 }
1104 
1105 int
1106 kern_kldunload(struct thread *td, int fileid, int flags)
1107 {
1108 	linker_file_t lf;
1109 	int error = 0;
1110 
1111 	if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
1112 		return (error);
1113 
1114 	if ((error = priv_check(td, PRIV_KLD_UNLOAD)) != 0)
1115 		return (error);
1116 
1117 	CURVNET_SET(TD_TO_VNET(td));
1118 	sx_xlock(&kld_sx);
1119 	lf = linker_find_file_by_id(fileid);
1120 	if (lf) {
1121 		KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
1122 
1123 		if (lf->userrefs == 0) {
1124 			/*
1125 			 * XXX: maybe LINKER_UNLOAD_FORCE should override ?
1126 			 */
1127 			printf("kldunload: attempt to unload file that was"
1128 			    " loaded by the kernel\n");
1129 			error = EBUSY;
1130 		} else {
1131 			lf->userrefs--;
1132 			error = linker_file_unload(lf, flags);
1133 			if (error)
1134 				lf->userrefs++;
1135 		}
1136 	} else
1137 		error = ENOENT;
1138 	sx_xunlock(&kld_sx);
1139 
1140 	CURVNET_RESTORE();
1141 	return (error);
1142 }
1143 
1144 int
1145 sys_kldunload(struct thread *td, struct kldunload_args *uap)
1146 {
1147 
1148 	return (kern_kldunload(td, uap->fileid, LINKER_UNLOAD_NORMAL));
1149 }
1150 
1151 int
1152 sys_kldunloadf(struct thread *td, struct kldunloadf_args *uap)
1153 {
1154 
1155 	if (uap->flags != LINKER_UNLOAD_NORMAL &&
1156 	    uap->flags != LINKER_UNLOAD_FORCE)
1157 		return (EINVAL);
1158 	return (kern_kldunload(td, uap->fileid, uap->flags));
1159 }
1160 
1161 int
1162 sys_kldfind(struct thread *td, struct kldfind_args *uap)
1163 {
1164 	char *pathname;
1165 	const char *filename;
1166 	linker_file_t lf;
1167 	int error;
1168 
1169 #ifdef MAC
1170 	error = mac_kld_check_stat(td->td_ucred);
1171 	if (error)
1172 		return (error);
1173 #endif
1174 
1175 	td->td_retval[0] = -1;
1176 
1177 	pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1178 	if ((error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL)) != 0)
1179 		goto out;
1180 
1181 	filename = linker_basename(pathname);
1182 	sx_xlock(&kld_sx);
1183 	lf = linker_find_file_by_name(filename);
1184 	if (lf)
1185 		td->td_retval[0] = lf->id;
1186 	else
1187 		error = ENOENT;
1188 	sx_xunlock(&kld_sx);
1189 out:
1190 	free(pathname, M_TEMP);
1191 	return (error);
1192 }
1193 
1194 int
1195 sys_kldnext(struct thread *td, struct kldnext_args *uap)
1196 {
1197 	linker_file_t lf;
1198 	int error = 0;
1199 
1200 #ifdef MAC
1201 	error = mac_kld_check_stat(td->td_ucred);
1202 	if (error)
1203 		return (error);
1204 #endif
1205 
1206 	sx_xlock(&kld_sx);
1207 	if (uap->fileid == 0)
1208 		lf = TAILQ_FIRST(&linker_files);
1209 	else {
1210 		lf = linker_find_file_by_id(uap->fileid);
1211 		if (lf == NULL) {
1212 			error = ENOENT;
1213 			goto out;
1214 		}
1215 		lf = TAILQ_NEXT(lf, link);
1216 	}
1217 
1218 	/* Skip partially loaded files. */
1219 	while (lf != NULL && !(lf->flags & LINKER_FILE_LINKED))
1220 		lf = TAILQ_NEXT(lf, link);
1221 
1222 	if (lf)
1223 		td->td_retval[0] = lf->id;
1224 	else
1225 		td->td_retval[0] = 0;
1226 out:
1227 	sx_xunlock(&kld_sx);
1228 	return (error);
1229 }
1230 
1231 int
1232 sys_kldstat(struct thread *td, struct kldstat_args *uap)
1233 {
1234 	struct kld_file_stat *stat;
1235 	int error, version;
1236 
1237 	/*
1238 	 * Check the version of the user's structure.
1239 	 */
1240 	if ((error = copyin(&uap->stat->version, &version, sizeof(version)))
1241 	    != 0)
1242 		return (error);
1243 	if (version != sizeof(struct kld_file_stat_1) &&
1244 	    version != sizeof(struct kld_file_stat))
1245 		return (EINVAL);
1246 
1247 	stat = malloc(sizeof(*stat), M_TEMP, M_WAITOK | M_ZERO);
1248 	error = kern_kldstat(td, uap->fileid, stat);
1249 	if (error == 0)
1250 		error = copyout(stat, uap->stat, version);
1251 	free(stat, M_TEMP);
1252 	return (error);
1253 }
1254 
1255 int
1256 kern_kldstat(struct thread *td, int fileid, struct kld_file_stat *stat)
1257 {
1258 	linker_file_t lf;
1259 	int namelen;
1260 #ifdef MAC
1261 	int error;
1262 
1263 	error = mac_kld_check_stat(td->td_ucred);
1264 	if (error)
1265 		return (error);
1266 #endif
1267 
1268 	sx_xlock(&kld_sx);
1269 	lf = linker_find_file_by_id(fileid);
1270 	if (lf == NULL) {
1271 		sx_xunlock(&kld_sx);
1272 		return (ENOENT);
1273 	}
1274 
1275 	/* Version 1 fields: */
1276 	namelen = strlen(lf->filename) + 1;
1277 	if (namelen > sizeof(stat->name))
1278 		namelen = sizeof(stat->name);
1279 	bcopy(lf->filename, &stat->name[0], namelen);
1280 	stat->refs = lf->refs;
1281 	stat->id = lf->id;
1282 	stat->address = lf->address;
1283 	stat->size = lf->size;
1284 	/* Version 2 fields: */
1285 	namelen = strlen(lf->pathname) + 1;
1286 	if (namelen > sizeof(stat->pathname))
1287 		namelen = sizeof(stat->pathname);
1288 	bcopy(lf->pathname, &stat->pathname[0], namelen);
1289 	sx_xunlock(&kld_sx);
1290 
1291 	td->td_retval[0] = 0;
1292 	return (0);
1293 }
1294 
1295 #ifdef DDB
1296 DB_COMMAND(kldstat, db_kldstat)
1297 {
1298 	linker_file_t lf;
1299 
1300 #define	POINTER_WIDTH	((int)(sizeof(void *) * 2 + 2))
1301 	db_printf("Id Refs Address%*c Size     Name\n", POINTER_WIDTH - 7, ' ');
1302 #undef	POINTER_WIDTH
1303 	TAILQ_FOREACH(lf, &linker_files, link) {
1304 		if (db_pager_quit)
1305 			return;
1306 		db_printf("%2d %4d %p %-8zx %s\n", lf->id, lf->refs,
1307 		    lf->address, lf->size, lf->filename);
1308 	}
1309 }
1310 #endif /* DDB */
1311 
1312 int
1313 sys_kldfirstmod(struct thread *td, struct kldfirstmod_args *uap)
1314 {
1315 	linker_file_t lf;
1316 	module_t mp;
1317 	int error = 0;
1318 
1319 #ifdef MAC
1320 	error = mac_kld_check_stat(td->td_ucred);
1321 	if (error)
1322 		return (error);
1323 #endif
1324 
1325 	sx_xlock(&kld_sx);
1326 	lf = linker_find_file_by_id(uap->fileid);
1327 	if (lf) {
1328 		MOD_SLOCK;
1329 		mp = TAILQ_FIRST(&lf->modules);
1330 		if (mp != NULL)
1331 			td->td_retval[0] = module_getid(mp);
1332 		else
1333 			td->td_retval[0] = 0;
1334 		MOD_SUNLOCK;
1335 	} else
1336 		error = ENOENT;
1337 	sx_xunlock(&kld_sx);
1338 	return (error);
1339 }
1340 
1341 int
1342 sys_kldsym(struct thread *td, struct kldsym_args *uap)
1343 {
1344 	char *symstr = NULL;
1345 	c_linker_sym_t sym;
1346 	linker_symval_t symval;
1347 	linker_file_t lf;
1348 	struct kld_sym_lookup lookup;
1349 	int error = 0;
1350 
1351 #ifdef MAC
1352 	error = mac_kld_check_stat(td->td_ucred);
1353 	if (error)
1354 		return (error);
1355 #endif
1356 
1357 	if ((error = copyin(uap->data, &lookup, sizeof(lookup))) != 0)
1358 		return (error);
1359 	if (lookup.version != sizeof(lookup) ||
1360 	    uap->cmd != KLDSYM_LOOKUP)
1361 		return (EINVAL);
1362 	symstr = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1363 	if ((error = copyinstr(lookup.symname, symstr, MAXPATHLEN, NULL)) != 0)
1364 		goto out;
1365 	sx_xlock(&kld_sx);
1366 	if (uap->fileid != 0) {
1367 		lf = linker_find_file_by_id(uap->fileid);
1368 		if (lf == NULL)
1369 			error = ENOENT;
1370 		else if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
1371 		    LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
1372 			lookup.symvalue = (uintptr_t) symval.value;
1373 			lookup.symsize = symval.size;
1374 			error = copyout(&lookup, uap->data, sizeof(lookup));
1375 		} else
1376 			error = ENOENT;
1377 	} else {
1378 		TAILQ_FOREACH(lf, &linker_files, link) {
1379 			if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
1380 			    LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
1381 				lookup.symvalue = (uintptr_t)symval.value;
1382 				lookup.symsize = symval.size;
1383 				error = copyout(&lookup, uap->data,
1384 				    sizeof(lookup));
1385 				break;
1386 			}
1387 		}
1388 		if (lf == NULL)
1389 			error = ENOENT;
1390 	}
1391 	sx_xunlock(&kld_sx);
1392 out:
1393 	free(symstr, M_TEMP);
1394 	return (error);
1395 }
1396 
1397 /*
1398  * Preloaded module support
1399  */
1400 
1401 static modlist_t
1402 modlist_lookup(const char *name, int ver)
1403 {
1404 	modlist_t mod;
1405 
1406 	TAILQ_FOREACH(mod, &found_modules, link) {
1407 		if (strcmp(mod->name, name) == 0 &&
1408 		    (ver == 0 || mod->version == ver))
1409 			return (mod);
1410 	}
1411 	return (NULL);
1412 }
1413 
1414 static modlist_t
1415 modlist_lookup2(const char *name, const struct mod_depend *verinfo)
1416 {
1417 	modlist_t mod, bestmod;
1418 	int ver;
1419 
1420 	if (verinfo == NULL)
1421 		return (modlist_lookup(name, 0));
1422 	bestmod = NULL;
1423 	TAILQ_FOREACH(mod, &found_modules, link) {
1424 		if (strcmp(mod->name, name) != 0)
1425 			continue;
1426 		ver = mod->version;
1427 		if (ver == verinfo->md_ver_preferred)
1428 			return (mod);
1429 		if (ver >= verinfo->md_ver_minimum &&
1430 		    ver <= verinfo->md_ver_maximum &&
1431 		    (bestmod == NULL || ver > bestmod->version))
1432 			bestmod = mod;
1433 	}
1434 	return (bestmod);
1435 }
1436 
1437 static modlist_t
1438 modlist_newmodule(const char *modname, int version, linker_file_t container)
1439 {
1440 	modlist_t mod;
1441 
1442 	mod = malloc(sizeof(struct modlist), M_LINKER, M_NOWAIT | M_ZERO);
1443 	if (mod == NULL)
1444 		panic("no memory for module list");
1445 	mod->container = container;
1446 	mod->name = modname;
1447 	mod->version = version;
1448 	TAILQ_INSERT_TAIL(&found_modules, mod, link);
1449 	return (mod);
1450 }
1451 
1452 static void
1453 linker_addmodules(linker_file_t lf, struct mod_metadata **start,
1454     struct mod_metadata **stop, int preload)
1455 {
1456 	struct mod_metadata *mp, **mdp;
1457 	const char *modname;
1458 	int ver;
1459 
1460 	for (mdp = start; mdp < stop; mdp++) {
1461 		mp = *mdp;
1462 		if (mp->md_type != MDT_VERSION)
1463 			continue;
1464 		modname = mp->md_cval;
1465 		ver = ((const struct mod_version *)mp->md_data)->mv_version;
1466 		if (modlist_lookup(modname, ver) != NULL) {
1467 			printf("module %s already present!\n", modname);
1468 			/* XXX what can we do? this is a build error. :-( */
1469 			continue;
1470 		}
1471 		modlist_newmodule(modname, ver, lf);
1472 	}
1473 }
1474 
1475 static void
1476 linker_preload(void *arg)
1477 {
1478 	caddr_t modptr;
1479 	const char *modname, *nmodname;
1480 	char *modtype;
1481 	linker_file_t lf, nlf;
1482 	linker_class_t lc;
1483 	int error;
1484 	linker_file_list_t loaded_files;
1485 	linker_file_list_t depended_files;
1486 	struct mod_metadata *mp, *nmp;
1487 	struct mod_metadata **start, **stop, **mdp, **nmdp;
1488 	const struct mod_depend *verinfo;
1489 	int nver;
1490 	int resolves;
1491 	modlist_t mod;
1492 	struct sysinit **si_start, **si_stop;
1493 
1494 	TAILQ_INIT(&loaded_files);
1495 	TAILQ_INIT(&depended_files);
1496 	TAILQ_INIT(&found_modules);
1497 	error = 0;
1498 
1499 	modptr = NULL;
1500 	sx_xlock(&kld_sx);
1501 	while ((modptr = preload_search_next_name(modptr)) != NULL) {
1502 		modname = (char *)preload_search_info(modptr, MODINFO_NAME);
1503 		modtype = (char *)preload_search_info(modptr, MODINFO_TYPE);
1504 		if (modname == NULL) {
1505 			printf("Preloaded module at %p does not have a"
1506 			    " name!\n", modptr);
1507 			continue;
1508 		}
1509 		if (modtype == NULL) {
1510 			printf("Preloaded module at %p does not have a type!\n",
1511 			    modptr);
1512 			continue;
1513 		}
1514 		if (bootverbose)
1515 			printf("Preloaded %s \"%s\" at %p.\n", modtype, modname,
1516 			    modptr);
1517 		lf = NULL;
1518 		TAILQ_FOREACH(lc, &classes, link) {
1519 			error = LINKER_LINK_PRELOAD(lc, modname, &lf);
1520 			if (!error)
1521 				break;
1522 			lf = NULL;
1523 		}
1524 		if (lf)
1525 			TAILQ_INSERT_TAIL(&loaded_files, lf, loaded);
1526 	}
1527 
1528 	/*
1529 	 * First get a list of stuff in the kernel.
1530 	 */
1531 	if (linker_file_lookup_set(linker_kernel_file, MDT_SETNAME, &start,
1532 	    &stop, NULL) == 0)
1533 		linker_addmodules(linker_kernel_file, start, stop, 1);
1534 
1535 	/*
1536 	 * This is a once-off kinky bubble sort to resolve relocation
1537 	 * dependency requirements.
1538 	 */
1539 restart:
1540 	TAILQ_FOREACH(lf, &loaded_files, loaded) {
1541 		error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
1542 		    &stop, NULL);
1543 		/*
1544 		 * First, look to see if we would successfully link with this
1545 		 * stuff.
1546 		 */
1547 		resolves = 1;	/* unless we know otherwise */
1548 		if (!error) {
1549 			for (mdp = start; mdp < stop; mdp++) {
1550 				mp = *mdp;
1551 				if (mp->md_type != MDT_DEPEND)
1552 					continue;
1553 				modname = mp->md_cval;
1554 				verinfo = mp->md_data;
1555 				for (nmdp = start; nmdp < stop; nmdp++) {
1556 					nmp = *nmdp;
1557 					if (nmp->md_type != MDT_VERSION)
1558 						continue;
1559 					nmodname = nmp->md_cval;
1560 					if (strcmp(modname, nmodname) == 0)
1561 						break;
1562 				}
1563 				if (nmdp < stop)   /* it's a self reference */
1564 					continue;
1565 
1566 				/*
1567 				 * ok, the module isn't here yet, we
1568 				 * are not finished
1569 				 */
1570 				if (modlist_lookup2(modname, verinfo) == NULL)
1571 					resolves = 0;
1572 			}
1573 		}
1574 		/*
1575 		 * OK, if we found our modules, we can link.  So, "provide"
1576 		 * the modules inside and add it to the end of the link order
1577 		 * list.
1578 		 */
1579 		if (resolves) {
1580 			if (!error) {
1581 				for (mdp = start; mdp < stop; mdp++) {
1582 					mp = *mdp;
1583 					if (mp->md_type != MDT_VERSION)
1584 						continue;
1585 					modname = mp->md_cval;
1586 					nver = ((const struct mod_version *)
1587 					    mp->md_data)->mv_version;
1588 					if (modlist_lookup(modname,
1589 					    nver) != NULL) {
1590 						printf("module %s already"
1591 						    " present!\n", modname);
1592 						TAILQ_REMOVE(&loaded_files,
1593 						    lf, loaded);
1594 						linker_file_unload(lf,
1595 						    LINKER_UNLOAD_FORCE);
1596 						/* we changed tailq next ptr */
1597 						goto restart;
1598 					}
1599 					modlist_newmodule(modname, nver, lf);
1600 				}
1601 			}
1602 			TAILQ_REMOVE(&loaded_files, lf, loaded);
1603 			TAILQ_INSERT_TAIL(&depended_files, lf, loaded);
1604 			/*
1605 			 * Since we provided modules, we need to restart the
1606 			 * sort so that the previous files that depend on us
1607 			 * have a chance. Also, we've busted the tailq next
1608 			 * pointer with the REMOVE.
1609 			 */
1610 			goto restart;
1611 		}
1612 	}
1613 
1614 	/*
1615 	 * At this point, we check to see what could not be resolved..
1616 	 */
1617 	while ((lf = TAILQ_FIRST(&loaded_files)) != NULL) {
1618 		TAILQ_REMOVE(&loaded_files, lf, loaded);
1619 		printf("KLD file %s is missing dependencies\n", lf->filename);
1620 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1621 	}
1622 
1623 	/*
1624 	 * We made it. Finish off the linking in the order we determined.
1625 	 */
1626 	TAILQ_FOREACH_SAFE(lf, &depended_files, loaded, nlf) {
1627 		if (linker_kernel_file) {
1628 			linker_kernel_file->refs++;
1629 			error = linker_file_add_dependency(lf,
1630 			    linker_kernel_file);
1631 			if (error)
1632 				panic("cannot add dependency");
1633 		}
1634 		error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
1635 		    &stop, NULL);
1636 		if (!error) {
1637 			for (mdp = start; mdp < stop; mdp++) {
1638 				mp = *mdp;
1639 				if (mp->md_type != MDT_DEPEND)
1640 					continue;
1641 				modname = mp->md_cval;
1642 				verinfo = mp->md_data;
1643 				mod = modlist_lookup2(modname, verinfo);
1644 				if (mod == NULL) {
1645 					printf("KLD file %s - cannot find "
1646 					    "dependency \"%s\"\n",
1647 					    lf->filename, modname);
1648 					goto fail;
1649 				}
1650 				/* Don't count self-dependencies */
1651 				if (lf == mod->container)
1652 					continue;
1653 				mod->container->refs++;
1654 				error = linker_file_add_dependency(lf,
1655 				    mod->container);
1656 				if (error)
1657 					panic("cannot add dependency");
1658 			}
1659 		}
1660 		/*
1661 		 * Now do relocation etc using the symbol search paths
1662 		 * established by the dependencies
1663 		 */
1664 		error = LINKER_LINK_PRELOAD_FINISH(lf);
1665 		if (error) {
1666 			printf("KLD file %s - could not finalize loading\n",
1667 			    lf->filename);
1668 			goto fail;
1669 		}
1670 		linker_file_register_modules(lf);
1671 		if (!TAILQ_EMPTY(&lf->modules))
1672 			lf->flags |= LINKER_FILE_MODULES;
1673 		if (linker_file_lookup_set(lf, "sysinit_set", &si_start,
1674 		    &si_stop, NULL) == 0)
1675 			sysinit_add(si_start, si_stop);
1676 		linker_file_register_sysctls(lf, true);
1677 		lf->flags |= LINKER_FILE_LINKED;
1678 		continue;
1679 fail:
1680 		TAILQ_REMOVE(&depended_files, lf, loaded);
1681 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1682 	}
1683 	sx_xunlock(&kld_sx);
1684 	/* woohoo! we made it! */
1685 }
1686 
1687 SYSINIT(preload, SI_SUB_KLD, SI_ORDER_MIDDLE, linker_preload, NULL);
1688 
1689 /*
1690  * Handle preload files that failed to load any modules.
1691  */
1692 static void
1693 linker_preload_finish(void *arg)
1694 {
1695 	linker_file_t lf, nlf;
1696 
1697 	sx_xlock(&kld_sx);
1698 	TAILQ_FOREACH_SAFE(lf, &linker_files, link, nlf) {
1699 		/*
1700 		 * If all of the modules in this file failed to load, unload
1701 		 * the file and return an error of ENOEXEC.  (Parity with
1702 		 * linker_load_file.)
1703 		 */
1704 		if ((lf->flags & LINKER_FILE_MODULES) != 0 &&
1705 		    TAILQ_EMPTY(&lf->modules)) {
1706 			linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1707 			continue;
1708 		}
1709 
1710 		lf->flags &= ~LINKER_FILE_MODULES;
1711 		lf->userrefs++;	/* so we can (try to) kldunload it */
1712 	}
1713 	sx_xunlock(&kld_sx);
1714 }
1715 
1716 /*
1717  * Attempt to run after all DECLARE_MODULE SYSINITs.  Unfortunately they can be
1718  * scheduled at any subsystem and order, so run this as late as possible.  init
1719  * becomes runnable in SI_SUB_KTHREAD_INIT, so go slightly before that.
1720  */
1721 SYSINIT(preload_finish, SI_SUB_KTHREAD_INIT - 100, SI_ORDER_MIDDLE,
1722     linker_preload_finish, NULL);
1723 
1724 /*
1725  * Search for a not-loaded module by name.
1726  *
1727  * Modules may be found in the following locations:
1728  *
1729  * - preloaded (result is just the module name) - on disk (result is full path
1730  * to module)
1731  *
1732  * If the module name is qualified in any way (contains path, etc.) the we
1733  * simply return a copy of it.
1734  *
1735  * The search path can be manipulated via sysctl.  Note that we use the ';'
1736  * character as a separator to be consistent with the bootloader.
1737  */
1738 
1739 static char linker_hintfile[] = "linker.hints";
1740 static char linker_path[MAXPATHLEN] = "/boot/kernel;/boot/modules";
1741 
1742 SYSCTL_STRING(_kern, OID_AUTO, module_path, CTLFLAG_RWTUN, linker_path,
1743     sizeof(linker_path), "module load search path");
1744 
1745 TUNABLE_STR("module_path", linker_path, sizeof(linker_path));
1746 
1747 static char *linker_ext_list[] = {
1748 	"",
1749 	".ko",
1750 	NULL
1751 };
1752 
1753 /*
1754  * Check if file actually exists either with or without extension listed in
1755  * the linker_ext_list. (probably should be generic for the rest of the
1756  * kernel)
1757  */
1758 static char *
1759 linker_lookup_file(const char *path, int pathlen, const char *name,
1760     int namelen, struct vattr *vap)
1761 {
1762 	struct nameidata nd;
1763 	struct thread *td = curthread;	/* XXX */
1764 	char *result, **cpp, *sep;
1765 	int error, len, extlen, reclen, flags;
1766 	enum vtype type;
1767 
1768 	extlen = 0;
1769 	for (cpp = linker_ext_list; *cpp; cpp++) {
1770 		len = strlen(*cpp);
1771 		if (len > extlen)
1772 			extlen = len;
1773 	}
1774 	extlen++;		/* trailing '\0' */
1775 	sep = (path[pathlen - 1] != '/') ? "/" : "";
1776 
1777 	reclen = pathlen + strlen(sep) + namelen + extlen + 1;
1778 	result = malloc(reclen, M_LINKER, M_WAITOK);
1779 	for (cpp = linker_ext_list; *cpp; cpp++) {
1780 		snprintf(result, reclen, "%.*s%s%.*s%s", pathlen, path, sep,
1781 		    namelen, name, *cpp);
1782 		/*
1783 		 * Attempt to open the file, and return the path if
1784 		 * we succeed and it's a regular file.
1785 		 */
1786 		NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, result, td);
1787 		flags = FREAD;
1788 		error = vn_open(&nd, &flags, 0, NULL);
1789 		if (error == 0) {
1790 			NDFREE(&nd, NDF_ONLY_PNBUF);
1791 			type = nd.ni_vp->v_type;
1792 			if (vap)
1793 				VOP_GETATTR(nd.ni_vp, vap, td->td_ucred);
1794 			VOP_UNLOCK(nd.ni_vp, 0);
1795 			vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1796 			if (type == VREG)
1797 				return (result);
1798 		}
1799 	}
1800 	free(result, M_LINKER);
1801 	return (NULL);
1802 }
1803 
1804 #define	INT_ALIGN(base, ptr)	ptr =					\
1805 	(base) + roundup2((ptr) - (base), sizeof(int))
1806 
1807 /*
1808  * Lookup KLD which contains requested module in the "linker.hints" file. If
1809  * version specification is available, then try to find the best KLD.
1810  * Otherwise just find the latest one.
1811  */
1812 static char *
1813 linker_hints_lookup(const char *path, int pathlen, const char *modname,
1814     int modnamelen, const struct mod_depend *verinfo)
1815 {
1816 	struct thread *td = curthread;	/* XXX */
1817 	struct ucred *cred = td ? td->td_ucred : NULL;
1818 	struct nameidata nd;
1819 	struct vattr vattr, mattr;
1820 	u_char *hints = NULL;
1821 	u_char *cp, *recptr, *bufend, *result, *best, *pathbuf, *sep;
1822 	int error, ival, bestver, *intp, found, flags, clen, blen;
1823 	ssize_t reclen;
1824 
1825 	result = NULL;
1826 	bestver = found = 0;
1827 
1828 	sep = (path[pathlen - 1] != '/') ? "/" : "";
1829 	reclen = imax(modnamelen, strlen(linker_hintfile)) + pathlen +
1830 	    strlen(sep) + 1;
1831 	pathbuf = malloc(reclen, M_LINKER, M_WAITOK);
1832 	snprintf(pathbuf, reclen, "%.*s%s%s", pathlen, path, sep,
1833 	    linker_hintfile);
1834 
1835 	NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, pathbuf, td);
1836 	flags = FREAD;
1837 	error = vn_open(&nd, &flags, 0, NULL);
1838 	if (error)
1839 		goto bad;
1840 	NDFREE(&nd, NDF_ONLY_PNBUF);
1841 	if (nd.ni_vp->v_type != VREG)
1842 		goto bad;
1843 	best = cp = NULL;
1844 	error = VOP_GETATTR(nd.ni_vp, &vattr, cred);
1845 	if (error)
1846 		goto bad;
1847 	/*
1848 	 * XXX: we need to limit this number to some reasonable value
1849 	 */
1850 	if (vattr.va_size > LINKER_HINTS_MAX) {
1851 		printf("hints file too large %ld\n", (long)vattr.va_size);
1852 		goto bad;
1853 	}
1854 	hints = malloc(vattr.va_size, M_TEMP, M_WAITOK);
1855 	error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)hints, vattr.va_size, 0,
1856 	    UIO_SYSSPACE, IO_NODELOCKED, cred, NOCRED, &reclen, td);
1857 	if (error)
1858 		goto bad;
1859 	VOP_UNLOCK(nd.ni_vp, 0);
1860 	vn_close(nd.ni_vp, FREAD, cred, td);
1861 	nd.ni_vp = NULL;
1862 	if (reclen != 0) {
1863 		printf("can't read %zd\n", reclen);
1864 		goto bad;
1865 	}
1866 	intp = (int *)hints;
1867 	ival = *intp++;
1868 	if (ival != LINKER_HINTS_VERSION) {
1869 		printf("hints file version mismatch %d\n", ival);
1870 		goto bad;
1871 	}
1872 	bufend = hints + vattr.va_size;
1873 	recptr = (u_char *)intp;
1874 	clen = blen = 0;
1875 	while (recptr < bufend && !found) {
1876 		intp = (int *)recptr;
1877 		reclen = *intp++;
1878 		ival = *intp++;
1879 		cp = (char *)intp;
1880 		switch (ival) {
1881 		case MDT_VERSION:
1882 			clen = *cp++;
1883 			if (clen != modnamelen || bcmp(cp, modname, clen) != 0)
1884 				break;
1885 			cp += clen;
1886 			INT_ALIGN(hints, cp);
1887 			ival = *(int *)cp;
1888 			cp += sizeof(int);
1889 			clen = *cp++;
1890 			if (verinfo == NULL ||
1891 			    ival == verinfo->md_ver_preferred) {
1892 				found = 1;
1893 				break;
1894 			}
1895 			if (ival >= verinfo->md_ver_minimum &&
1896 			    ival <= verinfo->md_ver_maximum &&
1897 			    ival > bestver) {
1898 				bestver = ival;
1899 				best = cp;
1900 				blen = clen;
1901 			}
1902 			break;
1903 		default:
1904 			break;
1905 		}
1906 		recptr += reclen + sizeof(int);
1907 	}
1908 	/*
1909 	 * Finally check if KLD is in the place
1910 	 */
1911 	if (found)
1912 		result = linker_lookup_file(path, pathlen, cp, clen, &mattr);
1913 	else if (best)
1914 		result = linker_lookup_file(path, pathlen, best, blen, &mattr);
1915 
1916 	/*
1917 	 * KLD is newer than hints file. What we should do now?
1918 	 */
1919 	if (result && timespeccmp(&mattr.va_mtime, &vattr.va_mtime, >))
1920 		printf("warning: KLD '%s' is newer than the linker.hints"
1921 		    " file\n", result);
1922 bad:
1923 	free(pathbuf, M_LINKER);
1924 	if (hints)
1925 		free(hints, M_TEMP);
1926 	if (nd.ni_vp != NULL) {
1927 		VOP_UNLOCK(nd.ni_vp, 0);
1928 		vn_close(nd.ni_vp, FREAD, cred, td);
1929 	}
1930 	/*
1931 	 * If nothing found or hints is absent - fallback to the old
1932 	 * way by using "kldname[.ko]" as module name.
1933 	 */
1934 	if (!found && !bestver && result == NULL)
1935 		result = linker_lookup_file(path, pathlen, modname,
1936 		    modnamelen, NULL);
1937 	return (result);
1938 }
1939 
1940 /*
1941  * Lookup KLD which contains requested module in the all directories.
1942  */
1943 static char *
1944 linker_search_module(const char *modname, int modnamelen,
1945     const struct mod_depend *verinfo)
1946 {
1947 	char *cp, *ep, *result;
1948 
1949 	/*
1950 	 * traverse the linker path
1951 	 */
1952 	for (cp = linker_path; *cp; cp = ep + 1) {
1953 		/* find the end of this component */
1954 		for (ep = cp; (*ep != 0) && (*ep != ';'); ep++);
1955 		result = linker_hints_lookup(cp, ep - cp, modname,
1956 		    modnamelen, verinfo);
1957 		if (result != NULL)
1958 			return (result);
1959 		if (*ep == 0)
1960 			break;
1961 	}
1962 	return (NULL);
1963 }
1964 
1965 /*
1966  * Search for module in all directories listed in the linker_path.
1967  */
1968 static char *
1969 linker_search_kld(const char *name)
1970 {
1971 	char *cp, *ep, *result;
1972 	int len;
1973 
1974 	/* qualified at all? */
1975 	if (strchr(name, '/'))
1976 		return (strdup(name, M_LINKER));
1977 
1978 	/* traverse the linker path */
1979 	len = strlen(name);
1980 	for (ep = linker_path; *ep; ep++) {
1981 		cp = ep;
1982 		/* find the end of this component */
1983 		for (; *ep != 0 && *ep != ';'; ep++);
1984 		result = linker_lookup_file(cp, ep - cp, name, len, NULL);
1985 		if (result != NULL)
1986 			return (result);
1987 	}
1988 	return (NULL);
1989 }
1990 
1991 static const char *
1992 linker_basename(const char *path)
1993 {
1994 	const char *filename;
1995 
1996 	filename = strrchr(path, '/');
1997 	if (filename == NULL)
1998 		return path;
1999 	if (filename[1])
2000 		filename++;
2001 	return (filename);
2002 }
2003 
2004 #ifdef HWPMC_HOOKS
2005 /*
2006  * Inform hwpmc about the set of kernel modules currently loaded.
2007  */
2008 void *
2009 linker_hwpmc_list_objects(void)
2010 {
2011 	linker_file_t lf;
2012 	struct pmckern_map_in *kobase;
2013 	int i, nmappings;
2014 
2015 	nmappings = 0;
2016 	sx_slock(&kld_sx);
2017 	TAILQ_FOREACH(lf, &linker_files, link)
2018 		nmappings++;
2019 
2020 	/* Allocate nmappings + 1 entries. */
2021 	kobase = malloc((nmappings + 1) * sizeof(struct pmckern_map_in),
2022 	    M_LINKER, M_WAITOK | M_ZERO);
2023 	i = 0;
2024 	TAILQ_FOREACH(lf, &linker_files, link) {
2025 
2026 		/* Save the info for this linker file. */
2027 		kobase[i].pm_file = lf->filename;
2028 		kobase[i].pm_address = (uintptr_t)lf->address;
2029 		i++;
2030 	}
2031 	sx_sunlock(&kld_sx);
2032 
2033 	KASSERT(i > 0, ("linker_hpwmc_list_objects: no kernel objects?"));
2034 
2035 	/* The last entry of the malloced area comprises of all zeros. */
2036 	KASSERT(kobase[i].pm_file == NULL,
2037 	    ("linker_hwpmc_list_objects: last object not NULL"));
2038 
2039 	return ((void *)kobase);
2040 }
2041 #endif
2042 
2043 /*
2044  * Find a file which contains given module and load it, if "parent" is not
2045  * NULL, register a reference to it.
2046  */
2047 static int
2048 linker_load_module(const char *kldname, const char *modname,
2049     struct linker_file *parent, const struct mod_depend *verinfo,
2050     struct linker_file **lfpp)
2051 {
2052 	linker_file_t lfdep;
2053 	const char *filename;
2054 	char *pathname;
2055 	int error;
2056 
2057 	sx_assert(&kld_sx, SA_XLOCKED);
2058 	if (modname == NULL) {
2059 		/*
2060  		 * We have to load KLD
2061  		 */
2062 		KASSERT(verinfo == NULL, ("linker_load_module: verinfo"
2063 		    " is not NULL"));
2064 		pathname = linker_search_kld(kldname);
2065 	} else {
2066 		if (modlist_lookup2(modname, verinfo) != NULL)
2067 			return (EEXIST);
2068 		if (kldname != NULL)
2069 			pathname = strdup(kldname, M_LINKER);
2070 		else if (rootvnode == NULL)
2071 			pathname = NULL;
2072 		else
2073 			/*
2074 			 * Need to find a KLD with required module
2075 			 */
2076 			pathname = linker_search_module(modname,
2077 			    strlen(modname), verinfo);
2078 	}
2079 	if (pathname == NULL)
2080 		return (ENOENT);
2081 
2082 	/*
2083 	 * Can't load more than one file with the same basename XXX:
2084 	 * Actually it should be possible to have multiple KLDs with
2085 	 * the same basename but different path because they can
2086 	 * provide different versions of the same modules.
2087 	 */
2088 	filename = linker_basename(pathname);
2089 	if (linker_find_file_by_name(filename))
2090 		error = EEXIST;
2091 	else do {
2092 		error = linker_load_file(pathname, &lfdep);
2093 		if (error)
2094 			break;
2095 		if (modname && verinfo &&
2096 		    modlist_lookup2(modname, verinfo) == NULL) {
2097 			linker_file_unload(lfdep, LINKER_UNLOAD_FORCE);
2098 			error = ENOENT;
2099 			break;
2100 		}
2101 		if (parent) {
2102 			error = linker_file_add_dependency(parent, lfdep);
2103 			if (error)
2104 				break;
2105 		}
2106 		if (lfpp)
2107 			*lfpp = lfdep;
2108 	} while (0);
2109 	free(pathname, M_LINKER);
2110 	return (error);
2111 }
2112 
2113 /*
2114  * This routine is responsible for finding dependencies of userland initiated
2115  * kldload(2)'s of files.
2116  */
2117 int
2118 linker_load_dependencies(linker_file_t lf)
2119 {
2120 	linker_file_t lfdep;
2121 	struct mod_metadata **start, **stop, **mdp, **nmdp;
2122 	struct mod_metadata *mp, *nmp;
2123 	const struct mod_depend *verinfo;
2124 	modlist_t mod;
2125 	const char *modname, *nmodname;
2126 	int ver, error = 0, count;
2127 
2128 	/*
2129 	 * All files are dependent on /kernel.
2130 	 */
2131 	sx_assert(&kld_sx, SA_XLOCKED);
2132 	if (linker_kernel_file) {
2133 		linker_kernel_file->refs++;
2134 		error = linker_file_add_dependency(lf, linker_kernel_file);
2135 		if (error)
2136 			return (error);
2137 	}
2138 	if (linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop,
2139 	    &count) != 0)
2140 		return (0);
2141 	for (mdp = start; mdp < stop; mdp++) {
2142 		mp = *mdp;
2143 		if (mp->md_type != MDT_VERSION)
2144 			continue;
2145 		modname = mp->md_cval;
2146 		ver = ((const struct mod_version *)mp->md_data)->mv_version;
2147 		mod = modlist_lookup(modname, ver);
2148 		if (mod != NULL) {
2149 			printf("interface %s.%d already present in the KLD"
2150 			    " '%s'!\n", modname, ver,
2151 			    mod->container->filename);
2152 			return (EEXIST);
2153 		}
2154 	}
2155 
2156 	for (mdp = start; mdp < stop; mdp++) {
2157 		mp = *mdp;
2158 		if (mp->md_type != MDT_DEPEND)
2159 			continue;
2160 		modname = mp->md_cval;
2161 		verinfo = mp->md_data;
2162 		nmodname = NULL;
2163 		for (nmdp = start; nmdp < stop; nmdp++) {
2164 			nmp = *nmdp;
2165 			if (nmp->md_type != MDT_VERSION)
2166 				continue;
2167 			nmodname = nmp->md_cval;
2168 			if (strcmp(modname, nmodname) == 0)
2169 				break;
2170 		}
2171 		if (nmdp < stop)/* early exit, it's a self reference */
2172 			continue;
2173 		mod = modlist_lookup2(modname, verinfo);
2174 		if (mod) {	/* woohoo, it's loaded already */
2175 			lfdep = mod->container;
2176 			lfdep->refs++;
2177 			error = linker_file_add_dependency(lf, lfdep);
2178 			if (error)
2179 				break;
2180 			continue;
2181 		}
2182 		error = linker_load_module(NULL, modname, lf, verinfo, NULL);
2183 		if (error) {
2184 			printf("KLD %s: depends on %s - not available or"
2185 			    " version mismatch\n", lf->filename, modname);
2186 			break;
2187 		}
2188 	}
2189 
2190 	if (error)
2191 		return (error);
2192 	linker_addmodules(lf, start, stop, 0);
2193 	return (error);
2194 }
2195 
2196 static int
2197 sysctl_kern_function_list_iterate(const char *name, void *opaque)
2198 {
2199 	struct sysctl_req *req;
2200 
2201 	req = opaque;
2202 	return (SYSCTL_OUT(req, name, strlen(name) + 1));
2203 }
2204 
2205 /*
2206  * Export a nul-separated, double-nul-terminated list of all function names
2207  * in the kernel.
2208  */
2209 static int
2210 sysctl_kern_function_list(SYSCTL_HANDLER_ARGS)
2211 {
2212 	linker_file_t lf;
2213 	int error;
2214 
2215 #ifdef MAC
2216 	error = mac_kld_check_stat(req->td->td_ucred);
2217 	if (error)
2218 		return (error);
2219 #endif
2220 	error = sysctl_wire_old_buffer(req, 0);
2221 	if (error != 0)
2222 		return (error);
2223 	sx_xlock(&kld_sx);
2224 	TAILQ_FOREACH(lf, &linker_files, link) {
2225 		error = LINKER_EACH_FUNCTION_NAME(lf,
2226 		    sysctl_kern_function_list_iterate, req);
2227 		if (error) {
2228 			sx_xunlock(&kld_sx);
2229 			return (error);
2230 		}
2231 	}
2232 	sx_xunlock(&kld_sx);
2233 	return (SYSCTL_OUT(req, "", 1));
2234 }
2235 
2236 SYSCTL_PROC(_kern, OID_AUTO, function_list, CTLTYPE_OPAQUE | CTLFLAG_RD,
2237     NULL, 0, sysctl_kern_function_list, "", "kernel function list");
2238