xref: /freebsd/sys/kern/kern_linker.c (revision 2f513db72b034fd5ef7f080b11be5c711c15186a)
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 /* XXX wrong name; we're looking at version provision tags here, not modules */
137 typedef TAILQ_HEAD(, modlist) modlisthead_t;
138 struct modlist {
139 	TAILQ_ENTRY(modlist) link;	/* chain together all modules */
140 	linker_file_t   container;
141 	const char 	*name;
142 	int             version;
143 };
144 typedef struct modlist *modlist_t;
145 static modlisthead_t found_modules;
146 
147 static int	linker_file_add_dependency(linker_file_t file,
148 		    linker_file_t dep);
149 static caddr_t	linker_file_lookup_symbol_internal(linker_file_t file,
150 		    const char* name, int deps);
151 static int	linker_load_module(const char *kldname,
152 		    const char *modname, struct linker_file *parent,
153 		    const struct mod_depend *verinfo, struct linker_file **lfpp);
154 static modlist_t modlist_lookup2(const char *name, const struct mod_depend *verinfo);
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, NULL);
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 	sx_assert(&kld_sx, SA_XLOCKED);
202 
203 	if (linker_file_lookup_set(lf, "sysinit_set", &start, &stop, NULL) != 0)
204 		return;
205 	/*
206 	 * Perform a bubble sort of the system initialization objects by
207 	 * their subsystem (primary key) and order (secondary key).
208 	 *
209 	 * Since some things care about execution order, this is the operation
210 	 * which ensures continued function.
211 	 */
212 	for (sipp = start; sipp < stop; sipp++) {
213 		for (xipp = sipp + 1; xipp < stop; xipp++) {
214 			if ((*sipp)->subsystem < (*xipp)->subsystem ||
215 			    ((*sipp)->subsystem == (*xipp)->subsystem &&
216 			    (*sipp)->order <= (*xipp)->order))
217 				continue;	/* skip */
218 			save = *sipp;
219 			*sipp = *xipp;
220 			*xipp = save;
221 		}
222 	}
223 
224 	/*
225 	 * Traverse the (now) ordered list of system initialization tasks.
226 	 * Perform each task, and continue on to the next task.
227 	 */
228 	sx_xunlock(&kld_sx);
229 	mtx_lock(&Giant);
230 	for (sipp = start; sipp < stop; sipp++) {
231 		if ((*sipp)->subsystem == SI_SUB_DUMMY)
232 			continue;	/* skip dummy task(s) */
233 
234 		/* Call function */
235 		(*((*sipp)->func)) ((*sipp)->udata);
236 	}
237 	mtx_unlock(&Giant);
238 	sx_xlock(&kld_sx);
239 }
240 
241 static void
242 linker_file_sysuninit(linker_file_t lf)
243 {
244 	struct sysinit **start, **stop, **sipp, **xipp, *save;
245 
246 	KLD_DPF(FILE, ("linker_file_sysuninit: calling SYSUNINITs for %s\n",
247 	    lf->filename));
248 
249 	sx_assert(&kld_sx, SA_XLOCKED);
250 
251 	if (linker_file_lookup_set(lf, "sysuninit_set", &start, &stop,
252 	    NULL) != 0)
253 		return;
254 
255 	/*
256 	 * Perform a reverse bubble sort of the system initialization objects
257 	 * by their subsystem (primary key) and order (secondary key).
258 	 *
259 	 * Since some things care about execution order, this is the operation
260 	 * which ensures continued function.
261 	 */
262 	for (sipp = start; sipp < stop; sipp++) {
263 		for (xipp = sipp + 1; xipp < stop; xipp++) {
264 			if ((*sipp)->subsystem > (*xipp)->subsystem ||
265 			    ((*sipp)->subsystem == (*xipp)->subsystem &&
266 			    (*sipp)->order >= (*xipp)->order))
267 				continue;	/* skip */
268 			save = *sipp;
269 			*sipp = *xipp;
270 			*xipp = save;
271 		}
272 	}
273 
274 	/*
275 	 * Traverse the (now) ordered list of system initialization tasks.
276 	 * Perform each task, and continue on to the next task.
277 	 */
278 	sx_xunlock(&kld_sx);
279 	mtx_lock(&Giant);
280 	for (sipp = start; sipp < stop; sipp++) {
281 		if ((*sipp)->subsystem == SI_SUB_DUMMY)
282 			continue;	/* skip dummy task(s) */
283 
284 		/* Call function */
285 		(*((*sipp)->func)) ((*sipp)->udata);
286 	}
287 	mtx_unlock(&Giant);
288 	sx_xlock(&kld_sx);
289 }
290 
291 static void
292 linker_file_register_sysctls(linker_file_t lf, bool enable)
293 {
294 	struct sysctl_oid **start, **stop, **oidp;
295 
296 	KLD_DPF(FILE,
297 	    ("linker_file_register_sysctls: registering SYSCTLs for %s\n",
298 	    lf->filename));
299 
300 	sx_assert(&kld_sx, SA_XLOCKED);
301 
302 	if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
303 		return;
304 
305 	sx_xunlock(&kld_sx);
306 	sysctl_wlock();
307 	for (oidp = start; oidp < stop; oidp++) {
308 		if (enable)
309 			sysctl_register_oid(*oidp);
310 		else
311 			sysctl_register_disabled_oid(*oidp);
312 	}
313 	sysctl_wunlock();
314 	sx_xlock(&kld_sx);
315 }
316 
317 static void
318 linker_file_enable_sysctls(linker_file_t lf)
319 {
320 	struct sysctl_oid **start, **stop, **oidp;
321 
322 	KLD_DPF(FILE,
323 	    ("linker_file_enable_sysctls: enable SYSCTLs for %s\n",
324 	    lf->filename));
325 
326 	sx_assert(&kld_sx, SA_XLOCKED);
327 
328 	if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
329 		return;
330 
331 	sx_xunlock(&kld_sx);
332 	sysctl_wlock();
333 	for (oidp = start; oidp < stop; oidp++)
334 		sysctl_enable_oid(*oidp);
335 	sysctl_wunlock();
336 	sx_xlock(&kld_sx);
337 }
338 
339 static void
340 linker_file_unregister_sysctls(linker_file_t lf)
341 {
342 	struct sysctl_oid **start, **stop, **oidp;
343 
344 	KLD_DPF(FILE, ("linker_file_unregister_sysctls: unregistering SYSCTLs"
345 	    " for %s\n", lf->filename));
346 
347 	sx_assert(&kld_sx, SA_XLOCKED);
348 
349 	if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
350 		return;
351 
352 	sx_xunlock(&kld_sx);
353 	sysctl_wlock();
354 	for (oidp = start; oidp < stop; oidp++)
355 		sysctl_unregister_oid(*oidp);
356 	sysctl_wunlock();
357 	sx_xlock(&kld_sx);
358 }
359 
360 static int
361 linker_file_register_modules(linker_file_t lf)
362 {
363 	struct mod_metadata **start, **stop, **mdp;
364 	const moduledata_t *moddata;
365 	int first_error, error;
366 
367 	KLD_DPF(FILE, ("linker_file_register_modules: registering modules"
368 	    " in %s\n", lf->filename));
369 
370 	sx_assert(&kld_sx, SA_XLOCKED);
371 
372 	if (linker_file_lookup_set(lf, "modmetadata_set", &start,
373 	    &stop, NULL) != 0) {
374 		/*
375 		 * This fallback should be unnecessary, but if we get booted
376 		 * from boot2 instead of loader and we are missing our
377 		 * metadata then we have to try the best we can.
378 		 */
379 		if (lf == linker_kernel_file) {
380 			start = SET_BEGIN(modmetadata_set);
381 			stop = SET_LIMIT(modmetadata_set);
382 		} else
383 			return (0);
384 	}
385 	first_error = 0;
386 	for (mdp = start; mdp < stop; mdp++) {
387 		if ((*mdp)->md_type != MDT_MODULE)
388 			continue;
389 		moddata = (*mdp)->md_data;
390 		KLD_DPF(FILE, ("Registering module %s in %s\n",
391 		    moddata->name, lf->filename));
392 		error = module_register(moddata, lf);
393 		if (error) {
394 			printf("Module %s failed to register: %d\n",
395 			    moddata->name, error);
396 			if (first_error == 0)
397 				first_error = error;
398 		}
399 	}
400 	return (first_error);
401 }
402 
403 static void
404 linker_init_kernel_modules(void)
405 {
406 
407 	sx_xlock(&kld_sx);
408 	linker_file_register_modules(linker_kernel_file);
409 	sx_xunlock(&kld_sx);
410 }
411 
412 SYSINIT(linker_kernel, SI_SUB_KLD, SI_ORDER_ANY, linker_init_kernel_modules,
413     NULL);
414 
415 static int
416 linker_load_file(const char *filename, linker_file_t *result)
417 {
418 	linker_class_t lc;
419 	linker_file_t lf;
420 	int foundfile, error, modules;
421 
422 	/* Refuse to load modules if securelevel raised */
423 	if (prison0.pr_securelevel > 0)
424 		return (EPERM);
425 
426 	sx_assert(&kld_sx, SA_XLOCKED);
427 	lf = linker_find_file_by_name(filename);
428 	if (lf) {
429 		KLD_DPF(FILE, ("linker_load_file: file %s is already loaded,"
430 		    " incrementing refs\n", filename));
431 		*result = lf;
432 		lf->refs++;
433 		return (0);
434 	}
435 	foundfile = 0;
436 	error = 0;
437 
438 	/*
439 	 * We do not need to protect (lock) classes here because there is
440 	 * no class registration past startup (SI_SUB_KLD, SI_ORDER_ANY)
441 	 * and there is no class deregistration mechanism at this time.
442 	 */
443 	TAILQ_FOREACH(lc, &classes, link) {
444 		KLD_DPF(FILE, ("linker_load_file: trying to load %s\n",
445 		    filename));
446 		error = LINKER_LOAD_FILE(lc, filename, &lf);
447 		/*
448 		 * If we got something other than ENOENT, then it exists but
449 		 * we cannot load it for some other reason.
450 		 */
451 		if (error != ENOENT)
452 			foundfile = 1;
453 		if (lf) {
454 			error = linker_file_register_modules(lf);
455 			if (error == EEXIST) {
456 				linker_file_unload(lf, LINKER_UNLOAD_FORCE);
457 				return (error);
458 			}
459 			modules = !TAILQ_EMPTY(&lf->modules);
460 			linker_file_register_sysctls(lf, false);
461 			linker_file_sysinit(lf);
462 			lf->flags |= LINKER_FILE_LINKED;
463 
464 			/*
465 			 * If all of the modules in this file failed
466 			 * to load, unload the file and return an
467 			 * error of ENOEXEC.
468 			 */
469 			if (modules && TAILQ_EMPTY(&lf->modules)) {
470 				linker_file_unload(lf, LINKER_UNLOAD_FORCE);
471 				return (ENOEXEC);
472 			}
473 			linker_file_enable_sysctls(lf);
474 			EVENTHANDLER_INVOKE(kld_load, lf);
475 			*result = lf;
476 			return (0);
477 		}
478 	}
479 	/*
480 	 * Less than ideal, but tells the user whether it failed to load or
481 	 * the module was not found.
482 	 */
483 	if (foundfile) {
484 
485 		/*
486 		 * If the file type has not been recognized by the last try
487 		 * printout a message before to fail.
488 		 */
489 		if (error == ENOSYS)
490 			printf("%s: %s - unsupported file type\n",
491 			    __func__, filename);
492 
493 		/*
494 		 * Format not recognized or otherwise unloadable.
495 		 * When loading a module that is statically built into
496 		 * the kernel EEXIST percolates back up as the return
497 		 * value.  Preserve this so that apps like sysinstall
498 		 * can recognize this special case and not post bogus
499 		 * dialog boxes.
500 		 */
501 		if (error != EEXIST)
502 			error = ENOEXEC;
503 	} else
504 		error = ENOENT;		/* Nothing found */
505 	return (error);
506 }
507 
508 int
509 linker_reference_module(const char *modname, struct mod_depend *verinfo,
510     linker_file_t *result)
511 {
512 	modlist_t mod;
513 	int error;
514 
515 	sx_xlock(&kld_sx);
516 	if ((mod = modlist_lookup2(modname, verinfo)) != NULL) {
517 		*result = mod->container;
518 		(*result)->refs++;
519 		sx_xunlock(&kld_sx);
520 		return (0);
521 	}
522 
523 	error = linker_load_module(NULL, modname, NULL, verinfo, result);
524 	sx_xunlock(&kld_sx);
525 	return (error);
526 }
527 
528 int
529 linker_release_module(const char *modname, struct mod_depend *verinfo,
530     linker_file_t lf)
531 {
532 	modlist_t mod;
533 	int error;
534 
535 	sx_xlock(&kld_sx);
536 	if (lf == NULL) {
537 		KASSERT(modname != NULL,
538 		    ("linker_release_module: no file or name"));
539 		mod = modlist_lookup2(modname, verinfo);
540 		if (mod == NULL) {
541 			sx_xunlock(&kld_sx);
542 			return (ESRCH);
543 		}
544 		lf = mod->container;
545 	} else
546 		KASSERT(modname == NULL && verinfo == NULL,
547 		    ("linker_release_module: both file and name"));
548 	error =	linker_file_unload(lf, LINKER_UNLOAD_NORMAL);
549 	sx_xunlock(&kld_sx);
550 	return (error);
551 }
552 
553 static linker_file_t
554 linker_find_file_by_name(const char *filename)
555 {
556 	linker_file_t lf;
557 	char *koname;
558 
559 	koname = malloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
560 	sprintf(koname, "%s.ko", filename);
561 
562 	sx_assert(&kld_sx, SA_XLOCKED);
563 	TAILQ_FOREACH(lf, &linker_files, link) {
564 		if (strcmp(lf->filename, koname) == 0)
565 			break;
566 		if (strcmp(lf->filename, filename) == 0)
567 			break;
568 	}
569 	free(koname, M_LINKER);
570 	return (lf);
571 }
572 
573 static linker_file_t
574 linker_find_file_by_id(int fileid)
575 {
576 	linker_file_t lf;
577 
578 	sx_assert(&kld_sx, SA_XLOCKED);
579 	TAILQ_FOREACH(lf, &linker_files, link)
580 		if (lf->id == fileid && lf->flags & LINKER_FILE_LINKED)
581 			break;
582 	return (lf);
583 }
584 
585 int
586 linker_file_foreach(linker_predicate_t *predicate, void *context)
587 {
588 	linker_file_t lf;
589 	int retval = 0;
590 
591 	sx_xlock(&kld_sx);
592 	TAILQ_FOREACH(lf, &linker_files, link) {
593 		retval = predicate(lf, context);
594 		if (retval != 0)
595 			break;
596 	}
597 	sx_xunlock(&kld_sx);
598 	return (retval);
599 }
600 
601 linker_file_t
602 linker_make_file(const char *pathname, linker_class_t lc)
603 {
604 	linker_file_t lf;
605 	const char *filename;
606 
607 	if (!cold)
608 		sx_assert(&kld_sx, SA_XLOCKED);
609 	filename = linker_basename(pathname);
610 
611 	KLD_DPF(FILE, ("linker_make_file: new file, filename='%s' for pathname='%s'\n", filename, pathname));
612 	lf = (linker_file_t)kobj_create((kobj_class_t)lc, M_LINKER, M_WAITOK);
613 	if (lf == NULL)
614 		return (NULL);
615 	lf->ctors_addr = 0;
616 	lf->ctors_size = 0;
617 	lf->refs = 1;
618 	lf->userrefs = 0;
619 	lf->flags = 0;
620 	lf->filename = strdup(filename, M_LINKER);
621 	lf->pathname = strdup(pathname, M_LINKER);
622 	LINKER_GET_NEXT_FILE_ID(lf->id);
623 	lf->ndeps = 0;
624 	lf->deps = NULL;
625 	lf->loadcnt = ++loadcnt;
626 #ifdef __arm__
627 	lf->exidx_addr = 0;
628 	lf->exidx_size = 0;
629 #endif
630 	STAILQ_INIT(&lf->common);
631 	TAILQ_INIT(&lf->modules);
632 	TAILQ_INSERT_TAIL(&linker_files, lf, link);
633 	return (lf);
634 }
635 
636 int
637 linker_file_unload(linker_file_t file, int flags)
638 {
639 	module_t mod, next;
640 	modlist_t ml, nextml;
641 	struct common_symbol *cp;
642 	int error, i;
643 
644 	/* Refuse to unload modules if securelevel raised. */
645 	if (prison0.pr_securelevel > 0)
646 		return (EPERM);
647 
648 	sx_assert(&kld_sx, SA_XLOCKED);
649 	KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
650 
651 	/* Easy case of just dropping a reference. */
652 	if (file->refs > 1) {
653 		file->refs--;
654 		return (0);
655 	}
656 
657 	/* Give eventhandlers a chance to prevent the unload. */
658 	error = 0;
659 	EVENTHANDLER_INVOKE(kld_unload_try, file, &error);
660 	if (error != 0)
661 		return (EBUSY);
662 
663 	KLD_DPF(FILE, ("linker_file_unload: file is unloading,"
664 	    " informing modules\n"));
665 
666 	/*
667 	 * Quiesce all the modules to give them a chance to veto the unload.
668 	 */
669 	MOD_SLOCK;
670 	for (mod = TAILQ_FIRST(&file->modules); mod;
671 	     mod = module_getfnext(mod)) {
672 
673 		error = module_quiesce(mod);
674 		if (error != 0 && flags != LINKER_UNLOAD_FORCE) {
675 			KLD_DPF(FILE, ("linker_file_unload: module %s"
676 			    " vetoed unload\n", module_getname(mod)));
677 			/*
678 			 * XXX: Do we need to tell all the quiesced modules
679 			 * that they can resume work now via a new module
680 			 * event?
681 			 */
682 			MOD_SUNLOCK;
683 			return (error);
684 		}
685 	}
686 	MOD_SUNLOCK;
687 
688 	/*
689 	 * Inform any modules associated with this file that they are
690 	 * being unloaded.
691 	 */
692 	MOD_XLOCK;
693 	for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
694 		next = module_getfnext(mod);
695 		MOD_XUNLOCK;
696 
697 		/*
698 		 * Give the module a chance to veto the unload.
699 		 */
700 		if ((error = module_unload(mod)) != 0) {
701 #ifdef KLD_DEBUG
702 			MOD_SLOCK;
703 			KLD_DPF(FILE, ("linker_file_unload: module %s"
704 			    " failed unload\n", module_getname(mod)));
705 			MOD_SUNLOCK;
706 #endif
707 			return (error);
708 		}
709 		MOD_XLOCK;
710 		module_release(mod);
711 	}
712 	MOD_XUNLOCK;
713 
714 	TAILQ_FOREACH_SAFE(ml, &found_modules, link, nextml) {
715 		if (ml->container == file) {
716 			TAILQ_REMOVE(&found_modules, ml, link);
717 			free(ml, M_LINKER);
718 		}
719 	}
720 
721 	/*
722 	 * Don't try to run SYSUNINITs if we are unloaded due to a
723 	 * link error.
724 	 */
725 	if (file->flags & LINKER_FILE_LINKED) {
726 		file->flags &= ~LINKER_FILE_LINKED;
727 		linker_file_unregister_sysctls(file);
728 		linker_file_sysuninit(file);
729 	}
730 	TAILQ_REMOVE(&linker_files, file, link);
731 
732 	if (file->deps) {
733 		for (i = 0; i < file->ndeps; i++)
734 			linker_file_unload(file->deps[i], flags);
735 		free(file->deps, M_LINKER);
736 		file->deps = NULL;
737 	}
738 	while ((cp = STAILQ_FIRST(&file->common)) != NULL) {
739 		STAILQ_REMOVE_HEAD(&file->common, link);
740 		free(cp, M_LINKER);
741 	}
742 
743 	LINKER_UNLOAD(file);
744 
745 	EVENTHANDLER_INVOKE(kld_unload, file->filename, file->address,
746 	    file->size);
747 
748 	if (file->filename) {
749 		free(file->filename, M_LINKER);
750 		file->filename = NULL;
751 	}
752 	if (file->pathname) {
753 		free(file->pathname, M_LINKER);
754 		file->pathname = NULL;
755 	}
756 	kobj_delete((kobj_t) file, M_LINKER);
757 	return (0);
758 }
759 
760 int
761 linker_ctf_get(linker_file_t file, linker_ctf_t *lc)
762 {
763 	return (LINKER_CTF_GET(file, lc));
764 }
765 
766 static int
767 linker_file_add_dependency(linker_file_t file, linker_file_t dep)
768 {
769 	linker_file_t *newdeps;
770 
771 	sx_assert(&kld_sx, SA_XLOCKED);
772 	file->deps = realloc(file->deps, (file->ndeps + 1) * sizeof(*newdeps),
773 	    M_LINKER, M_WAITOK | M_ZERO);
774 	file->deps[file->ndeps] = dep;
775 	file->ndeps++;
776 	KLD_DPF(FILE, ("linker_file_add_dependency:"
777 	    " adding %s as dependency for %s\n",
778 	    dep->filename, file->filename));
779 	return (0);
780 }
781 
782 /*
783  * Locate a linker set and its contents.  This is a helper function to avoid
784  * linker_if.h exposure elsewhere.  Note: firstp and lastp are really void **.
785  * This function is used in this file so we can avoid having lots of (void **)
786  * casts.
787  */
788 int
789 linker_file_lookup_set(linker_file_t file, const char *name,
790     void *firstp, void *lastp, int *countp)
791 {
792 
793 	sx_assert(&kld_sx, SA_LOCKED);
794 	return (LINKER_LOOKUP_SET(file, name, firstp, lastp, countp));
795 }
796 
797 /*
798  * List all functions in a file.
799  */
800 int
801 linker_file_function_listall(linker_file_t lf,
802     linker_function_nameval_callback_t callback_func, void *arg)
803 {
804 	return (LINKER_EACH_FUNCTION_NAMEVAL(lf, callback_func, arg));
805 }
806 
807 caddr_t
808 linker_file_lookup_symbol(linker_file_t file, const char *name, int deps)
809 {
810 	caddr_t sym;
811 	int locked;
812 
813 	locked = sx_xlocked(&kld_sx);
814 	if (!locked)
815 		sx_xlock(&kld_sx);
816 	sym = linker_file_lookup_symbol_internal(file, name, deps);
817 	if (!locked)
818 		sx_xunlock(&kld_sx);
819 	return (sym);
820 }
821 
822 static caddr_t
823 linker_file_lookup_symbol_internal(linker_file_t file, const char *name,
824     int deps)
825 {
826 	c_linker_sym_t sym;
827 	linker_symval_t symval;
828 	caddr_t address;
829 	size_t common_size = 0;
830 	int i;
831 
832 	sx_assert(&kld_sx, SA_XLOCKED);
833 	KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n",
834 	    file, name, deps));
835 
836 	if (LINKER_LOOKUP_SYMBOL(file, name, &sym) == 0) {
837 		LINKER_SYMBOL_VALUES(file, sym, &symval);
838 		if (symval.value == 0)
839 			/*
840 			 * For commons, first look them up in the
841 			 * dependencies and only allocate space if not found
842 			 * there.
843 			 */
844 			common_size = symval.size;
845 		else {
846 			KLD_DPF(SYM, ("linker_file_lookup_symbol: symbol"
847 			    ".value=%p\n", symval.value));
848 			return (symval.value);
849 		}
850 	}
851 	if (deps) {
852 		for (i = 0; i < file->ndeps; i++) {
853 			address = linker_file_lookup_symbol_internal(
854 			    file->deps[i], name, 0);
855 			if (address) {
856 				KLD_DPF(SYM, ("linker_file_lookup_symbol:"
857 				    " deps value=%p\n", address));
858 				return (address);
859 			}
860 		}
861 	}
862 	if (common_size > 0) {
863 		/*
864 		 * This is a common symbol which was not found in the
865 		 * dependencies.  We maintain a simple common symbol table in
866 		 * the file object.
867 		 */
868 		struct common_symbol *cp;
869 
870 		STAILQ_FOREACH(cp, &file->common, link) {
871 			if (strcmp(cp->name, name) == 0) {
872 				KLD_DPF(SYM, ("linker_file_lookup_symbol:"
873 				    " old common value=%p\n", cp->address));
874 				return (cp->address);
875 			}
876 		}
877 		/*
878 		 * Round the symbol size up to align.
879 		 */
880 		common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
881 		cp = malloc(sizeof(struct common_symbol)
882 		    + common_size + strlen(name) + 1, M_LINKER,
883 		    M_WAITOK | M_ZERO);
884 		cp->address = (caddr_t)(cp + 1);
885 		cp->name = cp->address + common_size;
886 		strcpy(cp->name, name);
887 		bzero(cp->address, common_size);
888 		STAILQ_INSERT_TAIL(&file->common, cp, link);
889 
890 		KLD_DPF(SYM, ("linker_file_lookup_symbol: new common"
891 		    " value=%p\n", cp->address));
892 		return (cp->address);
893 	}
894 	KLD_DPF(SYM, ("linker_file_lookup_symbol: fail\n"));
895 	return (0);
896 }
897 
898 /*
899  * Both DDB and stack(9) rely on the kernel linker to provide forward and
900  * backward lookup of symbols.  However, DDB and sometimes stack(9) need to
901  * do this in a lockfree manner.  We provide a set of internal helper
902  * routines to perform these operations without locks, and then wrappers that
903  * optionally lock.
904  *
905  * linker_debug_lookup() is ifdef DDB as currently it's only used by DDB.
906  */
907 #ifdef DDB
908 static int
909 linker_debug_lookup(const char *symstr, c_linker_sym_t *sym)
910 {
911 	linker_file_t lf;
912 
913 	TAILQ_FOREACH(lf, &linker_files, link) {
914 		if (LINKER_LOOKUP_SYMBOL(lf, symstr, sym) == 0)
915 			return (0);
916 	}
917 	return (ENOENT);
918 }
919 #endif
920 
921 static int
922 linker_debug_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
923 {
924 	linker_file_t lf;
925 	c_linker_sym_t best, es;
926 	u_long diff, bestdiff, off;
927 
928 	best = 0;
929 	off = (uintptr_t)value;
930 	bestdiff = off;
931 	TAILQ_FOREACH(lf, &linker_files, link) {
932 		if (LINKER_SEARCH_SYMBOL(lf, value, &es, &diff) != 0)
933 			continue;
934 		if (es != 0 && diff < bestdiff) {
935 			best = es;
936 			bestdiff = diff;
937 		}
938 		if (bestdiff == 0)
939 			break;
940 	}
941 	if (best) {
942 		*sym = best;
943 		*diffp = bestdiff;
944 		return (0);
945 	} else {
946 		*sym = 0;
947 		*diffp = off;
948 		return (ENOENT);
949 	}
950 }
951 
952 static int
953 linker_debug_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
954 {
955 	linker_file_t lf;
956 
957 	TAILQ_FOREACH(lf, &linker_files, link) {
958 		if (LINKER_SYMBOL_VALUES(lf, sym, symval) == 0)
959 			return (0);
960 	}
961 	return (ENOENT);
962 }
963 
964 static int
965 linker_debug_search_symbol_name(caddr_t value, char *buf, u_int buflen,
966     long *offset)
967 {
968 	linker_symval_t symval;
969 	c_linker_sym_t sym;
970 	int error;
971 
972 	*offset = 0;
973 	error = linker_debug_search_symbol(value, &sym, offset);
974 	if (error)
975 		return (error);
976 	error = linker_debug_symbol_values(sym, &symval);
977 	if (error)
978 		return (error);
979 	strlcpy(buf, symval.name, buflen);
980 	return (0);
981 }
982 
983 /*
984  * DDB Helpers.  DDB has to look across multiple files with their own symbol
985  * tables and string tables.
986  *
987  * Note that we do not obey list locking protocols here.  We really don't need
988  * DDB to hang because somebody's got the lock held.  We'll take the chance
989  * that the files list is inconsistent instead.
990  */
991 #ifdef DDB
992 int
993 linker_ddb_lookup(const char *symstr, c_linker_sym_t *sym)
994 {
995 
996 	return (linker_debug_lookup(symstr, sym));
997 }
998 #endif
999 
1000 int
1001 linker_ddb_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
1002 {
1003 
1004 	return (linker_debug_search_symbol(value, sym, diffp));
1005 }
1006 
1007 int
1008 linker_ddb_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
1009 {
1010 
1011 	return (linker_debug_symbol_values(sym, symval));
1012 }
1013 
1014 int
1015 linker_ddb_search_symbol_name(caddr_t value, char *buf, u_int buflen,
1016     long *offset)
1017 {
1018 
1019 	return (linker_debug_search_symbol_name(value, buf, buflen, offset));
1020 }
1021 
1022 /*
1023  * stack(9) helper for non-debugging environemnts.  Unlike DDB helpers, we do
1024  * obey locking protocols, and offer a significantly less complex interface.
1025  */
1026 int
1027 linker_search_symbol_name_flags(caddr_t value, char *buf, u_int buflen,
1028     long *offset, int flags)
1029 {
1030 	int error;
1031 
1032 	KASSERT((flags & (M_NOWAIT | M_WAITOK)) != 0 &&
1033 	    (flags & (M_NOWAIT | M_WAITOK)) != (M_NOWAIT | M_WAITOK),
1034 	    ("%s: bad flags: 0x%x", __func__, flags));
1035 
1036 	if (flags & M_NOWAIT) {
1037 		if (!sx_try_slock(&kld_sx))
1038 			return (EWOULDBLOCK);
1039 	} else
1040 		sx_slock(&kld_sx);
1041 
1042 	error = linker_debug_search_symbol_name(value, buf, buflen, offset);
1043 	sx_sunlock(&kld_sx);
1044 	return (error);
1045 }
1046 
1047 int
1048 linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
1049     long *offset)
1050 {
1051 
1052 	return (linker_search_symbol_name_flags(value, buf, buflen, offset,
1053 	    M_WAITOK));
1054 }
1055 
1056 /*
1057  * Syscalls.
1058  */
1059 int
1060 kern_kldload(struct thread *td, const char *file, int *fileid)
1061 {
1062 	const char *kldname, *modname;
1063 	linker_file_t lf;
1064 	int error;
1065 
1066 	if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
1067 		return (error);
1068 
1069 	if ((error = priv_check(td, PRIV_KLD_LOAD)) != 0)
1070 		return (error);
1071 
1072 	/*
1073 	 * It is possible that kldloaded module will attach a new ifnet,
1074 	 * so vnet context must be set when this ocurs.
1075 	 */
1076 	CURVNET_SET(TD_TO_VNET(td));
1077 
1078 	/*
1079 	 * If file does not contain a qualified name or any dot in it
1080 	 * (kldname.ko, or kldname.ver.ko) treat it as an interface
1081 	 * name.
1082 	 */
1083 	if (strchr(file, '/') || strchr(file, '.')) {
1084 		kldname = file;
1085 		modname = NULL;
1086 	} else {
1087 		kldname = NULL;
1088 		modname = file;
1089 	}
1090 
1091 	sx_xlock(&kld_sx);
1092 	error = linker_load_module(kldname, modname, NULL, NULL, &lf);
1093 	if (error) {
1094 		sx_xunlock(&kld_sx);
1095 		goto done;
1096 	}
1097 	lf->userrefs++;
1098 	if (fileid != NULL)
1099 		*fileid = lf->id;
1100 	sx_xunlock(&kld_sx);
1101 
1102 done:
1103 	CURVNET_RESTORE();
1104 	return (error);
1105 }
1106 
1107 int
1108 sys_kldload(struct thread *td, struct kldload_args *uap)
1109 {
1110 	char *pathname = NULL;
1111 	int error, fileid;
1112 
1113 	td->td_retval[0] = -1;
1114 
1115 	pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1116 	error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL);
1117 	if (error == 0) {
1118 		error = kern_kldload(td, pathname, &fileid);
1119 		if (error == 0)
1120 			td->td_retval[0] = fileid;
1121 	}
1122 	free(pathname, M_TEMP);
1123 	return (error);
1124 }
1125 
1126 int
1127 kern_kldunload(struct thread *td, int fileid, int flags)
1128 {
1129 	linker_file_t lf;
1130 	int error = 0;
1131 
1132 	if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
1133 		return (error);
1134 
1135 	if ((error = priv_check(td, PRIV_KLD_UNLOAD)) != 0)
1136 		return (error);
1137 
1138 	CURVNET_SET(TD_TO_VNET(td));
1139 	sx_xlock(&kld_sx);
1140 	lf = linker_find_file_by_id(fileid);
1141 	if (lf) {
1142 		KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
1143 
1144 		if (lf->userrefs == 0) {
1145 			/*
1146 			 * XXX: maybe LINKER_UNLOAD_FORCE should override ?
1147 			 */
1148 			printf("kldunload: attempt to unload file that was"
1149 			    " loaded by the kernel\n");
1150 			error = EBUSY;
1151 		} else {
1152 			lf->userrefs--;
1153 			error = linker_file_unload(lf, flags);
1154 			if (error)
1155 				lf->userrefs++;
1156 		}
1157 	} else
1158 		error = ENOENT;
1159 	sx_xunlock(&kld_sx);
1160 
1161 	CURVNET_RESTORE();
1162 	return (error);
1163 }
1164 
1165 int
1166 sys_kldunload(struct thread *td, struct kldunload_args *uap)
1167 {
1168 
1169 	return (kern_kldunload(td, uap->fileid, LINKER_UNLOAD_NORMAL));
1170 }
1171 
1172 int
1173 sys_kldunloadf(struct thread *td, struct kldunloadf_args *uap)
1174 {
1175 
1176 	if (uap->flags != LINKER_UNLOAD_NORMAL &&
1177 	    uap->flags != LINKER_UNLOAD_FORCE)
1178 		return (EINVAL);
1179 	return (kern_kldunload(td, uap->fileid, uap->flags));
1180 }
1181 
1182 int
1183 sys_kldfind(struct thread *td, struct kldfind_args *uap)
1184 {
1185 	char *pathname;
1186 	const char *filename;
1187 	linker_file_t lf;
1188 	int error;
1189 
1190 #ifdef MAC
1191 	error = mac_kld_check_stat(td->td_ucred);
1192 	if (error)
1193 		return (error);
1194 #endif
1195 
1196 	td->td_retval[0] = -1;
1197 
1198 	pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1199 	if ((error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL)) != 0)
1200 		goto out;
1201 
1202 	filename = linker_basename(pathname);
1203 	sx_xlock(&kld_sx);
1204 	lf = linker_find_file_by_name(filename);
1205 	if (lf)
1206 		td->td_retval[0] = lf->id;
1207 	else
1208 		error = ENOENT;
1209 	sx_xunlock(&kld_sx);
1210 out:
1211 	free(pathname, M_TEMP);
1212 	return (error);
1213 }
1214 
1215 int
1216 sys_kldnext(struct thread *td, struct kldnext_args *uap)
1217 {
1218 	linker_file_t lf;
1219 	int error = 0;
1220 
1221 #ifdef MAC
1222 	error = mac_kld_check_stat(td->td_ucred);
1223 	if (error)
1224 		return (error);
1225 #endif
1226 
1227 	sx_xlock(&kld_sx);
1228 	if (uap->fileid == 0)
1229 		lf = TAILQ_FIRST(&linker_files);
1230 	else {
1231 		lf = linker_find_file_by_id(uap->fileid);
1232 		if (lf == NULL) {
1233 			error = ENOENT;
1234 			goto out;
1235 		}
1236 		lf = TAILQ_NEXT(lf, link);
1237 	}
1238 
1239 	/* Skip partially loaded files. */
1240 	while (lf != NULL && !(lf->flags & LINKER_FILE_LINKED))
1241 		lf = TAILQ_NEXT(lf, link);
1242 
1243 	if (lf)
1244 		td->td_retval[0] = lf->id;
1245 	else
1246 		td->td_retval[0] = 0;
1247 out:
1248 	sx_xunlock(&kld_sx);
1249 	return (error);
1250 }
1251 
1252 int
1253 sys_kldstat(struct thread *td, struct kldstat_args *uap)
1254 {
1255 	struct kld_file_stat *stat;
1256 	int error, version;
1257 
1258 	/*
1259 	 * Check the version of the user's structure.
1260 	 */
1261 	if ((error = copyin(&uap->stat->version, &version, sizeof(version)))
1262 	    != 0)
1263 		return (error);
1264 	if (version != sizeof(struct kld_file_stat_1) &&
1265 	    version != sizeof(struct kld_file_stat))
1266 		return (EINVAL);
1267 
1268 	stat = malloc(sizeof(*stat), M_TEMP, M_WAITOK | M_ZERO);
1269 	error = kern_kldstat(td, uap->fileid, stat);
1270 	if (error == 0)
1271 		error = copyout(stat, uap->stat, version);
1272 	free(stat, M_TEMP);
1273 	return (error);
1274 }
1275 
1276 int
1277 kern_kldstat(struct thread *td, int fileid, struct kld_file_stat *stat)
1278 {
1279 	linker_file_t lf;
1280 	int namelen;
1281 #ifdef MAC
1282 	int error;
1283 
1284 	error = mac_kld_check_stat(td->td_ucred);
1285 	if (error)
1286 		return (error);
1287 #endif
1288 
1289 	sx_xlock(&kld_sx);
1290 	lf = linker_find_file_by_id(fileid);
1291 	if (lf == NULL) {
1292 		sx_xunlock(&kld_sx);
1293 		return (ENOENT);
1294 	}
1295 
1296 	/* Version 1 fields: */
1297 	namelen = strlen(lf->filename) + 1;
1298 	if (namelen > sizeof(stat->name))
1299 		namelen = sizeof(stat->name);
1300 	bcopy(lf->filename, &stat->name[0], namelen);
1301 	stat->refs = lf->refs;
1302 	stat->id = lf->id;
1303 	stat->address = lf->address;
1304 	stat->size = lf->size;
1305 	/* Version 2 fields: */
1306 	namelen = strlen(lf->pathname) + 1;
1307 	if (namelen > sizeof(stat->pathname))
1308 		namelen = sizeof(stat->pathname);
1309 	bcopy(lf->pathname, &stat->pathname[0], namelen);
1310 	sx_xunlock(&kld_sx);
1311 
1312 	td->td_retval[0] = 0;
1313 	return (0);
1314 }
1315 
1316 #ifdef DDB
1317 DB_COMMAND(kldstat, db_kldstat)
1318 {
1319 	linker_file_t lf;
1320 
1321 #define	POINTER_WIDTH	((int)(sizeof(void *) * 2 + 2))
1322 	db_printf("Id Refs Address%*c Size     Name\n", POINTER_WIDTH - 7, ' ');
1323 #undef	POINTER_WIDTH
1324 	TAILQ_FOREACH(lf, &linker_files, link) {
1325 		if (db_pager_quit)
1326 			return;
1327 		db_printf("%2d %4d %p %-8zx %s\n", lf->id, lf->refs,
1328 		    lf->address, lf->size, lf->filename);
1329 	}
1330 }
1331 #endif /* DDB */
1332 
1333 int
1334 sys_kldfirstmod(struct thread *td, struct kldfirstmod_args *uap)
1335 {
1336 	linker_file_t lf;
1337 	module_t mp;
1338 	int error = 0;
1339 
1340 #ifdef MAC
1341 	error = mac_kld_check_stat(td->td_ucred);
1342 	if (error)
1343 		return (error);
1344 #endif
1345 
1346 	sx_xlock(&kld_sx);
1347 	lf = linker_find_file_by_id(uap->fileid);
1348 	if (lf) {
1349 		MOD_SLOCK;
1350 		mp = TAILQ_FIRST(&lf->modules);
1351 		if (mp != NULL)
1352 			td->td_retval[0] = module_getid(mp);
1353 		else
1354 			td->td_retval[0] = 0;
1355 		MOD_SUNLOCK;
1356 	} else
1357 		error = ENOENT;
1358 	sx_xunlock(&kld_sx);
1359 	return (error);
1360 }
1361 
1362 int
1363 sys_kldsym(struct thread *td, struct kldsym_args *uap)
1364 {
1365 	char *symstr = NULL;
1366 	c_linker_sym_t sym;
1367 	linker_symval_t symval;
1368 	linker_file_t lf;
1369 	struct kld_sym_lookup lookup;
1370 	int error = 0;
1371 
1372 #ifdef MAC
1373 	error = mac_kld_check_stat(td->td_ucred);
1374 	if (error)
1375 		return (error);
1376 #endif
1377 
1378 	if ((error = copyin(uap->data, &lookup, sizeof(lookup))) != 0)
1379 		return (error);
1380 	if (lookup.version != sizeof(lookup) ||
1381 	    uap->cmd != KLDSYM_LOOKUP)
1382 		return (EINVAL);
1383 	symstr = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1384 	if ((error = copyinstr(lookup.symname, symstr, MAXPATHLEN, NULL)) != 0)
1385 		goto out;
1386 	sx_xlock(&kld_sx);
1387 	if (uap->fileid != 0) {
1388 		lf = linker_find_file_by_id(uap->fileid);
1389 		if (lf == NULL)
1390 			error = ENOENT;
1391 		else if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
1392 		    LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
1393 			lookup.symvalue = (uintptr_t) symval.value;
1394 			lookup.symsize = symval.size;
1395 			error = copyout(&lookup, uap->data, sizeof(lookup));
1396 		} else
1397 			error = ENOENT;
1398 	} else {
1399 		TAILQ_FOREACH(lf, &linker_files, link) {
1400 			if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
1401 			    LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
1402 				lookup.symvalue = (uintptr_t)symval.value;
1403 				lookup.symsize = symval.size;
1404 				error = copyout(&lookup, uap->data,
1405 				    sizeof(lookup));
1406 				break;
1407 			}
1408 		}
1409 		if (lf == NULL)
1410 			error = ENOENT;
1411 	}
1412 	sx_xunlock(&kld_sx);
1413 out:
1414 	free(symstr, M_TEMP);
1415 	return (error);
1416 }
1417 
1418 /*
1419  * Preloaded module support
1420  */
1421 
1422 static modlist_t
1423 modlist_lookup(const char *name, int ver)
1424 {
1425 	modlist_t mod;
1426 
1427 	TAILQ_FOREACH(mod, &found_modules, link) {
1428 		if (strcmp(mod->name, name) == 0 &&
1429 		    (ver == 0 || mod->version == ver))
1430 			return (mod);
1431 	}
1432 	return (NULL);
1433 }
1434 
1435 static modlist_t
1436 modlist_lookup2(const char *name, const struct mod_depend *verinfo)
1437 {
1438 	modlist_t mod, bestmod;
1439 	int ver;
1440 
1441 	if (verinfo == NULL)
1442 		return (modlist_lookup(name, 0));
1443 	bestmod = NULL;
1444 	TAILQ_FOREACH(mod, &found_modules, link) {
1445 		if (strcmp(mod->name, name) != 0)
1446 			continue;
1447 		ver = mod->version;
1448 		if (ver == verinfo->md_ver_preferred)
1449 			return (mod);
1450 		if (ver >= verinfo->md_ver_minimum &&
1451 		    ver <= verinfo->md_ver_maximum &&
1452 		    (bestmod == NULL || ver > bestmod->version))
1453 			bestmod = mod;
1454 	}
1455 	return (bestmod);
1456 }
1457 
1458 static modlist_t
1459 modlist_newmodule(const char *modname, int version, linker_file_t container)
1460 {
1461 	modlist_t mod;
1462 
1463 	mod = malloc(sizeof(struct modlist), M_LINKER, M_NOWAIT | M_ZERO);
1464 	if (mod == NULL)
1465 		panic("no memory for module list");
1466 	mod->container = container;
1467 	mod->name = modname;
1468 	mod->version = version;
1469 	TAILQ_INSERT_TAIL(&found_modules, mod, link);
1470 	return (mod);
1471 }
1472 
1473 static void
1474 linker_addmodules(linker_file_t lf, struct mod_metadata **start,
1475     struct mod_metadata **stop, int preload)
1476 {
1477 	struct mod_metadata *mp, **mdp;
1478 	const char *modname;
1479 	int ver;
1480 
1481 	for (mdp = start; mdp < stop; mdp++) {
1482 		mp = *mdp;
1483 		if (mp->md_type != MDT_VERSION)
1484 			continue;
1485 		modname = mp->md_cval;
1486 		ver = ((const struct mod_version *)mp->md_data)->mv_version;
1487 		if (modlist_lookup(modname, ver) != NULL) {
1488 			printf("module %s already present!\n", modname);
1489 			/* XXX what can we do? this is a build error. :-( */
1490 			continue;
1491 		}
1492 		modlist_newmodule(modname, ver, lf);
1493 	}
1494 }
1495 
1496 static void
1497 linker_preload(void *arg)
1498 {
1499 	caddr_t modptr;
1500 	const char *modname, *nmodname;
1501 	char *modtype;
1502 	linker_file_t lf, nlf;
1503 	linker_class_t lc;
1504 	int error;
1505 	linker_file_list_t loaded_files;
1506 	linker_file_list_t depended_files;
1507 	struct mod_metadata *mp, *nmp;
1508 	struct mod_metadata **start, **stop, **mdp, **nmdp;
1509 	const struct mod_depend *verinfo;
1510 	int nver;
1511 	int resolves;
1512 	modlist_t mod;
1513 	struct sysinit **si_start, **si_stop;
1514 
1515 	TAILQ_INIT(&loaded_files);
1516 	TAILQ_INIT(&depended_files);
1517 	TAILQ_INIT(&found_modules);
1518 	error = 0;
1519 
1520 	modptr = NULL;
1521 	sx_xlock(&kld_sx);
1522 	while ((modptr = preload_search_next_name(modptr)) != NULL) {
1523 		modname = (char *)preload_search_info(modptr, MODINFO_NAME);
1524 		modtype = (char *)preload_search_info(modptr, MODINFO_TYPE);
1525 		if (modname == NULL) {
1526 			printf("Preloaded module at %p does not have a"
1527 			    " name!\n", modptr);
1528 			continue;
1529 		}
1530 		if (modtype == NULL) {
1531 			printf("Preloaded module at %p does not have a type!\n",
1532 			    modptr);
1533 			continue;
1534 		}
1535 		if (bootverbose)
1536 			printf("Preloaded %s \"%s\" at %p.\n", modtype, modname,
1537 			    modptr);
1538 		lf = NULL;
1539 		TAILQ_FOREACH(lc, &classes, link) {
1540 			error = LINKER_LINK_PRELOAD(lc, modname, &lf);
1541 			if (!error)
1542 				break;
1543 			lf = NULL;
1544 		}
1545 		if (lf)
1546 			TAILQ_INSERT_TAIL(&loaded_files, lf, loaded);
1547 	}
1548 
1549 	/*
1550 	 * First get a list of stuff in the kernel.
1551 	 */
1552 	if (linker_file_lookup_set(linker_kernel_file, MDT_SETNAME, &start,
1553 	    &stop, NULL) == 0)
1554 		linker_addmodules(linker_kernel_file, start, stop, 1);
1555 
1556 	/*
1557 	 * This is a once-off kinky bubble sort to resolve relocation
1558 	 * dependency requirements.
1559 	 */
1560 restart:
1561 	TAILQ_FOREACH(lf, &loaded_files, loaded) {
1562 		error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
1563 		    &stop, NULL);
1564 		/*
1565 		 * First, look to see if we would successfully link with this
1566 		 * stuff.
1567 		 */
1568 		resolves = 1;	/* unless we know otherwise */
1569 		if (!error) {
1570 			for (mdp = start; mdp < stop; mdp++) {
1571 				mp = *mdp;
1572 				if (mp->md_type != MDT_DEPEND)
1573 					continue;
1574 				modname = mp->md_cval;
1575 				verinfo = mp->md_data;
1576 				for (nmdp = start; nmdp < stop; nmdp++) {
1577 					nmp = *nmdp;
1578 					if (nmp->md_type != MDT_VERSION)
1579 						continue;
1580 					nmodname = nmp->md_cval;
1581 					if (strcmp(modname, nmodname) == 0)
1582 						break;
1583 				}
1584 				if (nmdp < stop)   /* it's a self reference */
1585 					continue;
1586 
1587 				/*
1588 				 * ok, the module isn't here yet, we
1589 				 * are not finished
1590 				 */
1591 				if (modlist_lookup2(modname, verinfo) == NULL)
1592 					resolves = 0;
1593 			}
1594 		}
1595 		/*
1596 		 * OK, if we found our modules, we can link.  So, "provide"
1597 		 * the modules inside and add it to the end of the link order
1598 		 * list.
1599 		 */
1600 		if (resolves) {
1601 			if (!error) {
1602 				for (mdp = start; mdp < stop; mdp++) {
1603 					mp = *mdp;
1604 					if (mp->md_type != MDT_VERSION)
1605 						continue;
1606 					modname = mp->md_cval;
1607 					nver = ((const struct mod_version *)
1608 					    mp->md_data)->mv_version;
1609 					if (modlist_lookup(modname,
1610 					    nver) != NULL) {
1611 						printf("module %s already"
1612 						    " present!\n", modname);
1613 						TAILQ_REMOVE(&loaded_files,
1614 						    lf, loaded);
1615 						linker_file_unload(lf,
1616 						    LINKER_UNLOAD_FORCE);
1617 						/* we changed tailq next ptr */
1618 						goto restart;
1619 					}
1620 					modlist_newmodule(modname, nver, lf);
1621 				}
1622 			}
1623 			TAILQ_REMOVE(&loaded_files, lf, loaded);
1624 			TAILQ_INSERT_TAIL(&depended_files, lf, loaded);
1625 			/*
1626 			 * Since we provided modules, we need to restart the
1627 			 * sort so that the previous files that depend on us
1628 			 * have a chance. Also, we've busted the tailq next
1629 			 * pointer with the REMOVE.
1630 			 */
1631 			goto restart;
1632 		}
1633 	}
1634 
1635 	/*
1636 	 * At this point, we check to see what could not be resolved..
1637 	 */
1638 	while ((lf = TAILQ_FIRST(&loaded_files)) != NULL) {
1639 		TAILQ_REMOVE(&loaded_files, lf, loaded);
1640 		printf("KLD file %s is missing dependencies\n", lf->filename);
1641 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1642 	}
1643 
1644 	/*
1645 	 * We made it. Finish off the linking in the order we determined.
1646 	 */
1647 	TAILQ_FOREACH_SAFE(lf, &depended_files, loaded, nlf) {
1648 		if (linker_kernel_file) {
1649 			linker_kernel_file->refs++;
1650 			error = linker_file_add_dependency(lf,
1651 			    linker_kernel_file);
1652 			if (error)
1653 				panic("cannot add dependency");
1654 		}
1655 		error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
1656 		    &stop, NULL);
1657 		if (!error) {
1658 			for (mdp = start; mdp < stop; mdp++) {
1659 				mp = *mdp;
1660 				if (mp->md_type != MDT_DEPEND)
1661 					continue;
1662 				modname = mp->md_cval;
1663 				verinfo = mp->md_data;
1664 				mod = modlist_lookup2(modname, verinfo);
1665 				if (mod == NULL) {
1666 					printf("KLD file %s - cannot find "
1667 					    "dependency \"%s\"\n",
1668 					    lf->filename, modname);
1669 					goto fail;
1670 				}
1671 				/* Don't count self-dependencies */
1672 				if (lf == mod->container)
1673 					continue;
1674 				mod->container->refs++;
1675 				error = linker_file_add_dependency(lf,
1676 				    mod->container);
1677 				if (error)
1678 					panic("cannot add dependency");
1679 			}
1680 		}
1681 		/*
1682 		 * Now do relocation etc using the symbol search paths
1683 		 * established by the dependencies
1684 		 */
1685 		error = LINKER_LINK_PRELOAD_FINISH(lf);
1686 		if (error) {
1687 			printf("KLD file %s - could not finalize loading\n",
1688 			    lf->filename);
1689 			goto fail;
1690 		}
1691 		linker_file_register_modules(lf);
1692 		if (!TAILQ_EMPTY(&lf->modules))
1693 			lf->flags |= LINKER_FILE_MODULES;
1694 		if (linker_file_lookup_set(lf, "sysinit_set", &si_start,
1695 		    &si_stop, NULL) == 0)
1696 			sysinit_add(si_start, si_stop);
1697 		linker_file_register_sysctls(lf, true);
1698 		lf->flags |= LINKER_FILE_LINKED;
1699 		continue;
1700 fail:
1701 		TAILQ_REMOVE(&depended_files, lf, loaded);
1702 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1703 	}
1704 	sx_xunlock(&kld_sx);
1705 	/* woohoo! we made it! */
1706 }
1707 
1708 SYSINIT(preload, SI_SUB_KLD, SI_ORDER_MIDDLE, linker_preload, NULL);
1709 
1710 /*
1711  * Handle preload files that failed to load any modules.
1712  */
1713 static void
1714 linker_preload_finish(void *arg)
1715 {
1716 	linker_file_t lf, nlf;
1717 
1718 	sx_xlock(&kld_sx);
1719 	TAILQ_FOREACH_SAFE(lf, &linker_files, link, nlf) {
1720 		/*
1721 		 * If all of the modules in this file failed to load, unload
1722 		 * the file and return an error of ENOEXEC.  (Parity with
1723 		 * linker_load_file.)
1724 		 */
1725 		if ((lf->flags & LINKER_FILE_MODULES) != 0 &&
1726 		    TAILQ_EMPTY(&lf->modules)) {
1727 			linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1728 			continue;
1729 		}
1730 
1731 		lf->flags &= ~LINKER_FILE_MODULES;
1732 		lf->userrefs++;	/* so we can (try to) kldunload it */
1733 	}
1734 	sx_xunlock(&kld_sx);
1735 }
1736 
1737 /*
1738  * Attempt to run after all DECLARE_MODULE SYSINITs.  Unfortunately they can be
1739  * scheduled at any subsystem and order, so run this as late as possible.  init
1740  * becomes runnable in SI_SUB_KTHREAD_INIT, so go slightly before that.
1741  */
1742 SYSINIT(preload_finish, SI_SUB_KTHREAD_INIT - 100, SI_ORDER_MIDDLE,
1743     linker_preload_finish, NULL);
1744 
1745 /*
1746  * Search for a not-loaded module by name.
1747  *
1748  * Modules may be found in the following locations:
1749  *
1750  * - preloaded (result is just the module name) - on disk (result is full path
1751  * to module)
1752  *
1753  * If the module name is qualified in any way (contains path, etc.) the we
1754  * simply return a copy of it.
1755  *
1756  * The search path can be manipulated via sysctl.  Note that we use the ';'
1757  * character as a separator to be consistent with the bootloader.
1758  */
1759 
1760 static char linker_hintfile[] = "linker.hints";
1761 static char linker_path[MAXPATHLEN] = "/boot/kernel;/boot/modules";
1762 
1763 SYSCTL_STRING(_kern, OID_AUTO, module_path, CTLFLAG_RWTUN, linker_path,
1764     sizeof(linker_path), "module load search path");
1765 
1766 TUNABLE_STR("module_path", linker_path, sizeof(linker_path));
1767 
1768 static char *linker_ext_list[] = {
1769 	"",
1770 	".ko",
1771 	NULL
1772 };
1773 
1774 /*
1775  * Check if file actually exists either with or without extension listed in
1776  * the linker_ext_list. (probably should be generic for the rest of the
1777  * kernel)
1778  */
1779 static char *
1780 linker_lookup_file(const char *path, int pathlen, const char *name,
1781     int namelen, struct vattr *vap)
1782 {
1783 	struct nameidata nd;
1784 	struct thread *td = curthread;	/* XXX */
1785 	char *result, **cpp, *sep;
1786 	int error, len, extlen, reclen, flags;
1787 	enum vtype type;
1788 
1789 	extlen = 0;
1790 	for (cpp = linker_ext_list; *cpp; cpp++) {
1791 		len = strlen(*cpp);
1792 		if (len > extlen)
1793 			extlen = len;
1794 	}
1795 	extlen++;		/* trailing '\0' */
1796 	sep = (path[pathlen - 1] != '/') ? "/" : "";
1797 
1798 	reclen = pathlen + strlen(sep) + namelen + extlen + 1;
1799 	result = malloc(reclen, M_LINKER, M_WAITOK);
1800 	for (cpp = linker_ext_list; *cpp; cpp++) {
1801 		snprintf(result, reclen, "%.*s%s%.*s%s", pathlen, path, sep,
1802 		    namelen, name, *cpp);
1803 		/*
1804 		 * Attempt to open the file, and return the path if
1805 		 * we succeed and it's a regular file.
1806 		 */
1807 		NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, result, td);
1808 		flags = FREAD;
1809 		error = vn_open(&nd, &flags, 0, NULL);
1810 		if (error == 0) {
1811 			NDFREE(&nd, NDF_ONLY_PNBUF);
1812 			type = nd.ni_vp->v_type;
1813 			if (vap)
1814 				VOP_GETATTR(nd.ni_vp, vap, td->td_ucred);
1815 			VOP_UNLOCK(nd.ni_vp);
1816 			vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1817 			if (type == VREG)
1818 				return (result);
1819 		}
1820 	}
1821 	free(result, M_LINKER);
1822 	return (NULL);
1823 }
1824 
1825 #define	INT_ALIGN(base, ptr)	ptr =					\
1826 	(base) + roundup2((ptr) - (base), sizeof(int))
1827 
1828 /*
1829  * Lookup KLD which contains requested module in the "linker.hints" file. If
1830  * version specification is available, then try to find the best KLD.
1831  * Otherwise just find the latest one.
1832  */
1833 static char *
1834 linker_hints_lookup(const char *path, int pathlen, const char *modname,
1835     int modnamelen, const struct mod_depend *verinfo)
1836 {
1837 	struct thread *td = curthread;	/* XXX */
1838 	struct ucred *cred = td ? td->td_ucred : NULL;
1839 	struct nameidata nd;
1840 	struct vattr vattr, mattr;
1841 	u_char *hints = NULL;
1842 	u_char *cp, *recptr, *bufend, *result, *best, *pathbuf, *sep;
1843 	int error, ival, bestver, *intp, found, flags, clen, blen;
1844 	ssize_t reclen;
1845 
1846 	result = NULL;
1847 	bestver = found = 0;
1848 
1849 	sep = (path[pathlen - 1] != '/') ? "/" : "";
1850 	reclen = imax(modnamelen, strlen(linker_hintfile)) + pathlen +
1851 	    strlen(sep) + 1;
1852 	pathbuf = malloc(reclen, M_LINKER, M_WAITOK);
1853 	snprintf(pathbuf, reclen, "%.*s%s%s", pathlen, path, sep,
1854 	    linker_hintfile);
1855 
1856 	NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, pathbuf, td);
1857 	flags = FREAD;
1858 	error = vn_open(&nd, &flags, 0, NULL);
1859 	if (error)
1860 		goto bad;
1861 	NDFREE(&nd, NDF_ONLY_PNBUF);
1862 	if (nd.ni_vp->v_type != VREG)
1863 		goto bad;
1864 	best = cp = NULL;
1865 	error = VOP_GETATTR(nd.ni_vp, &vattr, cred);
1866 	if (error)
1867 		goto bad;
1868 	/*
1869 	 * XXX: we need to limit this number to some reasonable value
1870 	 */
1871 	if (vattr.va_size > LINKER_HINTS_MAX) {
1872 		printf("hints file too large %ld\n", (long)vattr.va_size);
1873 		goto bad;
1874 	}
1875 	hints = malloc(vattr.va_size, M_TEMP, M_WAITOK);
1876 	error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)hints, vattr.va_size, 0,
1877 	    UIO_SYSSPACE, IO_NODELOCKED, cred, NOCRED, &reclen, td);
1878 	if (error)
1879 		goto bad;
1880 	VOP_UNLOCK(nd.ni_vp);
1881 	vn_close(nd.ni_vp, FREAD, cred, td);
1882 	nd.ni_vp = NULL;
1883 	if (reclen != 0) {
1884 		printf("can't read %zd\n", reclen);
1885 		goto bad;
1886 	}
1887 	intp = (int *)hints;
1888 	ival = *intp++;
1889 	if (ival != LINKER_HINTS_VERSION) {
1890 		printf("hints file version mismatch %d\n", ival);
1891 		goto bad;
1892 	}
1893 	bufend = hints + vattr.va_size;
1894 	recptr = (u_char *)intp;
1895 	clen = blen = 0;
1896 	while (recptr < bufend && !found) {
1897 		intp = (int *)recptr;
1898 		reclen = *intp++;
1899 		ival = *intp++;
1900 		cp = (char *)intp;
1901 		switch (ival) {
1902 		case MDT_VERSION:
1903 			clen = *cp++;
1904 			if (clen != modnamelen || bcmp(cp, modname, clen) != 0)
1905 				break;
1906 			cp += clen;
1907 			INT_ALIGN(hints, cp);
1908 			ival = *(int *)cp;
1909 			cp += sizeof(int);
1910 			clen = *cp++;
1911 			if (verinfo == NULL ||
1912 			    ival == verinfo->md_ver_preferred) {
1913 				found = 1;
1914 				break;
1915 			}
1916 			if (ival >= verinfo->md_ver_minimum &&
1917 			    ival <= verinfo->md_ver_maximum &&
1918 			    ival > bestver) {
1919 				bestver = ival;
1920 				best = cp;
1921 				blen = clen;
1922 			}
1923 			break;
1924 		default:
1925 			break;
1926 		}
1927 		recptr += reclen + sizeof(int);
1928 	}
1929 	/*
1930 	 * Finally check if KLD is in the place
1931 	 */
1932 	if (found)
1933 		result = linker_lookup_file(path, pathlen, cp, clen, &mattr);
1934 	else if (best)
1935 		result = linker_lookup_file(path, pathlen, best, blen, &mattr);
1936 
1937 	/*
1938 	 * KLD is newer than hints file. What we should do now?
1939 	 */
1940 	if (result && timespeccmp(&mattr.va_mtime, &vattr.va_mtime, >))
1941 		printf("warning: KLD '%s' is newer than the linker.hints"
1942 		    " file\n", result);
1943 bad:
1944 	free(pathbuf, M_LINKER);
1945 	if (hints)
1946 		free(hints, M_TEMP);
1947 	if (nd.ni_vp != NULL) {
1948 		VOP_UNLOCK(nd.ni_vp);
1949 		vn_close(nd.ni_vp, FREAD, cred, td);
1950 	}
1951 	/*
1952 	 * If nothing found or hints is absent - fallback to the old
1953 	 * way by using "kldname[.ko]" as module name.
1954 	 */
1955 	if (!found && !bestver && result == NULL)
1956 		result = linker_lookup_file(path, pathlen, modname,
1957 		    modnamelen, NULL);
1958 	return (result);
1959 }
1960 
1961 /*
1962  * Lookup KLD which contains requested module in the all directories.
1963  */
1964 static char *
1965 linker_search_module(const char *modname, int modnamelen,
1966     const struct mod_depend *verinfo)
1967 {
1968 	char *cp, *ep, *result;
1969 
1970 	/*
1971 	 * traverse the linker path
1972 	 */
1973 	for (cp = linker_path; *cp; cp = ep + 1) {
1974 		/* find the end of this component */
1975 		for (ep = cp; (*ep != 0) && (*ep != ';'); ep++);
1976 		result = linker_hints_lookup(cp, ep - cp, modname,
1977 		    modnamelen, verinfo);
1978 		if (result != NULL)
1979 			return (result);
1980 		if (*ep == 0)
1981 			break;
1982 	}
1983 	return (NULL);
1984 }
1985 
1986 /*
1987  * Search for module in all directories listed in the linker_path.
1988  */
1989 static char *
1990 linker_search_kld(const char *name)
1991 {
1992 	char *cp, *ep, *result;
1993 	int len;
1994 
1995 	/* qualified at all? */
1996 	if (strchr(name, '/'))
1997 		return (strdup(name, M_LINKER));
1998 
1999 	/* traverse the linker path */
2000 	len = strlen(name);
2001 	for (ep = linker_path; *ep; ep++) {
2002 		cp = ep;
2003 		/* find the end of this component */
2004 		for (; *ep != 0 && *ep != ';'; ep++);
2005 		result = linker_lookup_file(cp, ep - cp, name, len, NULL);
2006 		if (result != NULL)
2007 			return (result);
2008 	}
2009 	return (NULL);
2010 }
2011 
2012 static const char *
2013 linker_basename(const char *path)
2014 {
2015 	const char *filename;
2016 
2017 	filename = strrchr(path, '/');
2018 	if (filename == NULL)
2019 		return path;
2020 	if (filename[1])
2021 		filename++;
2022 	return (filename);
2023 }
2024 
2025 #ifdef HWPMC_HOOKS
2026 /*
2027  * Inform hwpmc about the set of kernel modules currently loaded.
2028  */
2029 void *
2030 linker_hwpmc_list_objects(void)
2031 {
2032 	linker_file_t lf;
2033 	struct pmckern_map_in *kobase;
2034 	int i, nmappings;
2035 
2036 	nmappings = 0;
2037 	sx_slock(&kld_sx);
2038 	TAILQ_FOREACH(lf, &linker_files, link)
2039 		nmappings++;
2040 
2041 	/* Allocate nmappings + 1 entries. */
2042 	kobase = malloc((nmappings + 1) * sizeof(struct pmckern_map_in),
2043 	    M_LINKER, M_WAITOK | M_ZERO);
2044 	i = 0;
2045 	TAILQ_FOREACH(lf, &linker_files, link) {
2046 
2047 		/* Save the info for this linker file. */
2048 		kobase[i].pm_file = lf->filename;
2049 		kobase[i].pm_address = (uintptr_t)lf->address;
2050 		i++;
2051 	}
2052 	sx_sunlock(&kld_sx);
2053 
2054 	KASSERT(i > 0, ("linker_hpwmc_list_objects: no kernel objects?"));
2055 
2056 	/* The last entry of the malloced area comprises of all zeros. */
2057 	KASSERT(kobase[i].pm_file == NULL,
2058 	    ("linker_hwpmc_list_objects: last object not NULL"));
2059 
2060 	return ((void *)kobase);
2061 }
2062 #endif
2063 
2064 /*
2065  * Find a file which contains given module and load it, if "parent" is not
2066  * NULL, register a reference to it.
2067  */
2068 static int
2069 linker_load_module(const char *kldname, const char *modname,
2070     struct linker_file *parent, const struct mod_depend *verinfo,
2071     struct linker_file **lfpp)
2072 {
2073 	linker_file_t lfdep;
2074 	const char *filename;
2075 	char *pathname;
2076 	int error;
2077 
2078 	sx_assert(&kld_sx, SA_XLOCKED);
2079 	if (modname == NULL) {
2080 		/*
2081  		 * We have to load KLD
2082  		 */
2083 		KASSERT(verinfo == NULL, ("linker_load_module: verinfo"
2084 		    " is not NULL"));
2085 		/* check if root file system is not mounted */
2086 		if (rootvnode == NULL || curproc->p_fd->fd_rdir == NULL)
2087 			return (ENXIO);
2088 		pathname = linker_search_kld(kldname);
2089 	} else {
2090 		if (modlist_lookup2(modname, verinfo) != NULL)
2091 			return (EEXIST);
2092 		/* check if root file system is not mounted */
2093 		if (rootvnode == NULL || curproc->p_fd->fd_rdir == NULL)
2094 			return (ENXIO);
2095 		if (kldname != NULL)
2096 			pathname = strdup(kldname, M_LINKER);
2097 		else
2098 			/*
2099 			 * Need to find a KLD with required module
2100 			 */
2101 			pathname = linker_search_module(modname,
2102 			    strlen(modname), verinfo);
2103 	}
2104 	if (pathname == NULL)
2105 		return (ENOENT);
2106 
2107 	/*
2108 	 * Can't load more than one file with the same basename XXX:
2109 	 * Actually it should be possible to have multiple KLDs with
2110 	 * the same basename but different path because they can
2111 	 * provide different versions of the same modules.
2112 	 */
2113 	filename = linker_basename(pathname);
2114 	if (linker_find_file_by_name(filename))
2115 		error = EEXIST;
2116 	else do {
2117 		error = linker_load_file(pathname, &lfdep);
2118 		if (error)
2119 			break;
2120 		if (modname && verinfo &&
2121 		    modlist_lookup2(modname, verinfo) == NULL) {
2122 			linker_file_unload(lfdep, LINKER_UNLOAD_FORCE);
2123 			error = ENOENT;
2124 			break;
2125 		}
2126 		if (parent) {
2127 			error = linker_file_add_dependency(parent, lfdep);
2128 			if (error)
2129 				break;
2130 		}
2131 		if (lfpp)
2132 			*lfpp = lfdep;
2133 	} while (0);
2134 	free(pathname, M_LINKER);
2135 	return (error);
2136 }
2137 
2138 /*
2139  * This routine is responsible for finding dependencies of userland initiated
2140  * kldload(2)'s of files.
2141  */
2142 int
2143 linker_load_dependencies(linker_file_t lf)
2144 {
2145 	linker_file_t lfdep;
2146 	struct mod_metadata **start, **stop, **mdp, **nmdp;
2147 	struct mod_metadata *mp, *nmp;
2148 	const struct mod_depend *verinfo;
2149 	modlist_t mod;
2150 	const char *modname, *nmodname;
2151 	int ver, error = 0;
2152 
2153 	/*
2154 	 * All files are dependent on /kernel.
2155 	 */
2156 	sx_assert(&kld_sx, SA_XLOCKED);
2157 	if (linker_kernel_file) {
2158 		linker_kernel_file->refs++;
2159 		error = linker_file_add_dependency(lf, linker_kernel_file);
2160 		if (error)
2161 			return (error);
2162 	}
2163 	if (linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop,
2164 	    NULL) != 0)
2165 		return (0);
2166 	for (mdp = start; mdp < stop; mdp++) {
2167 		mp = *mdp;
2168 		if (mp->md_type != MDT_VERSION)
2169 			continue;
2170 		modname = mp->md_cval;
2171 		ver = ((const struct mod_version *)mp->md_data)->mv_version;
2172 		mod = modlist_lookup(modname, ver);
2173 		if (mod != NULL) {
2174 			printf("interface %s.%d already present in the KLD"
2175 			    " '%s'!\n", modname, ver,
2176 			    mod->container->filename);
2177 			return (EEXIST);
2178 		}
2179 	}
2180 
2181 	for (mdp = start; mdp < stop; mdp++) {
2182 		mp = *mdp;
2183 		if (mp->md_type != MDT_DEPEND)
2184 			continue;
2185 		modname = mp->md_cval;
2186 		verinfo = mp->md_data;
2187 		nmodname = NULL;
2188 		for (nmdp = start; nmdp < stop; nmdp++) {
2189 			nmp = *nmdp;
2190 			if (nmp->md_type != MDT_VERSION)
2191 				continue;
2192 			nmodname = nmp->md_cval;
2193 			if (strcmp(modname, nmodname) == 0)
2194 				break;
2195 		}
2196 		if (nmdp < stop)/* early exit, it's a self reference */
2197 			continue;
2198 		mod = modlist_lookup2(modname, verinfo);
2199 		if (mod) {	/* woohoo, it's loaded already */
2200 			lfdep = mod->container;
2201 			lfdep->refs++;
2202 			error = linker_file_add_dependency(lf, lfdep);
2203 			if (error)
2204 				break;
2205 			continue;
2206 		}
2207 		error = linker_load_module(NULL, modname, lf, verinfo, NULL);
2208 		if (error) {
2209 			printf("KLD %s: depends on %s - not available or"
2210 			    " version mismatch\n", lf->filename, modname);
2211 			break;
2212 		}
2213 	}
2214 
2215 	if (error)
2216 		return (error);
2217 	linker_addmodules(lf, start, stop, 0);
2218 	return (error);
2219 }
2220 
2221 static int
2222 sysctl_kern_function_list_iterate(const char *name, void *opaque)
2223 {
2224 	struct sysctl_req *req;
2225 
2226 	req = opaque;
2227 	return (SYSCTL_OUT(req, name, strlen(name) + 1));
2228 }
2229 
2230 /*
2231  * Export a nul-separated, double-nul-terminated list of all function names
2232  * in the kernel.
2233  */
2234 static int
2235 sysctl_kern_function_list(SYSCTL_HANDLER_ARGS)
2236 {
2237 	linker_file_t lf;
2238 	int error;
2239 
2240 #ifdef MAC
2241 	error = mac_kld_check_stat(req->td->td_ucred);
2242 	if (error)
2243 		return (error);
2244 #endif
2245 	error = sysctl_wire_old_buffer(req, 0);
2246 	if (error != 0)
2247 		return (error);
2248 	sx_xlock(&kld_sx);
2249 	TAILQ_FOREACH(lf, &linker_files, link) {
2250 		error = LINKER_EACH_FUNCTION_NAME(lf,
2251 		    sysctl_kern_function_list_iterate, req);
2252 		if (error) {
2253 			sx_xunlock(&kld_sx);
2254 			return (error);
2255 		}
2256 	}
2257 	sx_xunlock(&kld_sx);
2258 	return (SYSCTL_OUT(req, "", 1));
2259 }
2260 
2261 SYSCTL_PROC(_kern, OID_AUTO, function_list, CTLTYPE_OPAQUE | CTLFLAG_RD,
2262     NULL, 0, sysctl_kern_function_list, "", "kernel function list");
2263