xref: /freebsd/sys/kern/kern_linker.c (revision b52f49a9a0f22207ad5130ad8faba08de3ed23d8)
1 /*-
2  * Copyright (c) 1997-2000 Doug Rabson
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include "opt_ddb.h"
31 #include "opt_mac.h"
32 
33 #include <sys/param.h>
34 #include <sys/kernel.h>
35 #include <sys/systm.h>
36 #include <sys/malloc.h>
37 #include <sys/sysproto.h>
38 #include <sys/sysent.h>
39 #include <sys/proc.h>
40 #include <sys/lock.h>
41 #include <sys/mutex.h>
42 #include <sys/sx.h>
43 #include <sys/mac.h>
44 #include <sys/module.h>
45 #include <sys/linker.h>
46 #include <sys/fcntl.h>
47 #include <sys/libkern.h>
48 #include <sys/namei.h>
49 #include <sys/vnode.h>
50 #include <sys/sysctl.h>
51 
52 #include "linker_if.h"
53 
54 #ifdef KLD_DEBUG
55 int kld_debug = 0;
56 #endif
57 
58 /*
59  * static char *linker_search_path(const char *name, struct mod_depend
60  * *verinfo);
61  */
62 static const char 	*linker_basename(const char *path);
63 
64 /* Metadata from the static kernel */
65 SET_DECLARE(modmetadata_set, struct mod_metadata);
66 
67 MALLOC_DEFINE(M_LINKER, "linker", "kernel linker");
68 
69 linker_file_t linker_kernel_file;
70 
71 static struct mtx kld_mtx;	/* kernel linker mutex */
72 
73 static linker_class_list_t classes;
74 static linker_file_list_t linker_files;
75 static int next_file_id = 1;
76 static int linker_no_more_classes = 0;
77 
78 #define	LINKER_GET_NEXT_FILE_ID(a) do {					\
79 	linker_file_t lftmp;						\
80 									\
81 retry:									\
82 	mtx_lock(&kld_mtx);						\
83 	TAILQ_FOREACH(lftmp, &linker_files, link) {			\
84 		if (next_file_id == lftmp->id) {			\
85 			next_file_id++;					\
86 			mtx_unlock(&kld_mtx);				\
87 			goto retry;					\
88 		}							\
89 	}								\
90 	(a) = next_file_id;						\
91 	mtx_unlock(&kld_mtx);	/* Hold for safe read of id variable */	\
92 } while(0)
93 
94 
95 /* XXX wrong name; we're looking at version provision tags here, not modules */
96 typedef TAILQ_HEAD(, modlist) modlisthead_t;
97 struct modlist {
98 	TAILQ_ENTRY(modlist) link;	/* chain together all modules */
99 	linker_file_t   container;
100 	const char 	*name;
101 	int             version;
102 };
103 typedef struct modlist *modlist_t;
104 static modlisthead_t found_modules;
105 
106 static modlist_t	modlist_lookup2(const char *name,
107 			    struct mod_depend *verinfo);
108 
109 static char *
110 linker_strdup(const char *str)
111 {
112 	char *result;
113 
114 	if ((result = malloc((strlen(str) + 1), M_LINKER, M_WAITOK)) != NULL)
115 		strcpy(result, str);
116 	return (result);
117 }
118 
119 static void
120 linker_init(void *arg)
121 {
122 
123 	mtx_init(&kld_mtx, "kernel linker", NULL, MTX_DEF);
124 	TAILQ_INIT(&classes);
125 	TAILQ_INIT(&linker_files);
126 }
127 
128 SYSINIT(linker, SI_SUB_KLD, SI_ORDER_FIRST, linker_init, 0)
129 
130 static void
131 linker_stop_class_add(void *arg)
132 {
133 
134 	linker_no_more_classes = 1;
135 }
136 
137 SYSINIT(linker_class, SI_SUB_KLD, SI_ORDER_ANY, linker_stop_class_add, NULL)
138 
139 int
140 linker_add_class(linker_class_t lc)
141 {
142 
143 	/*
144 	 * We disallow any class registration passt SI_ORDER_ANY
145 	 * of SI_SUB_KLD.
146 	 */
147 	if (linker_no_more_classes == 1)
148 		return (EPERM);
149 	kobj_class_compile((kobj_class_t) lc);
150 	TAILQ_INSERT_TAIL(&classes, lc, link);
151 	return (0);
152 }
153 
154 static void
155 linker_file_sysinit(linker_file_t lf)
156 {
157 	struct sysinit **start, **stop, **sipp, **xipp, *save;
158 
159 	KLD_DPF(FILE, ("linker_file_sysinit: calling SYSINITs for %s\n",
160 	    lf->filename));
161 
162 	if (linker_file_lookup_set(lf, "sysinit_set", &start, &stop, NULL) != 0)
163 		return;
164 	/*
165 	 * Perform a bubble sort of the system initialization objects by
166 	 * their subsystem (primary key) and order (secondary key).
167 	 *
168 	 * Since some things care about execution order, this is the operation
169 	 * which ensures continued function.
170 	 */
171 	for (sipp = start; sipp < stop; sipp++) {
172 		for (xipp = sipp + 1; xipp < stop; xipp++) {
173 			if ((*sipp)->subsystem < (*xipp)->subsystem ||
174 			    ((*sipp)->subsystem == (*xipp)->subsystem &&
175 			    (*sipp)->order <= (*xipp)->order))
176 				continue;	/* skip */
177 			save = *sipp;
178 			*sipp = *xipp;
179 			*xipp = save;
180 		}
181 	}
182 
183 	/*
184 	 * Traverse the (now) ordered list of system initialization tasks.
185 	 * Perform each task, and continue on to the next task.
186 	 */
187 	for (sipp = start; sipp < stop; sipp++) {
188 		if ((*sipp)->subsystem == SI_SUB_DUMMY)
189 			continue;	/* skip dummy task(s) */
190 
191 		/* Call function */
192 		(*((*sipp)->func)) ((*sipp)->udata);
193 	}
194 }
195 
196 static void
197 linker_file_sysuninit(linker_file_t lf)
198 {
199 	struct sysinit **start, **stop, **sipp, **xipp, *save;
200 
201 	KLD_DPF(FILE, ("linker_file_sysuninit: calling SYSUNINITs for %s\n",
202 	    lf->filename));
203 
204 	if (linker_file_lookup_set(lf, "sysuninit_set", &start, &stop,
205 	    NULL) != 0)
206 		return;
207 
208 	/*
209 	 * Perform a reverse bubble sort of the system initialization objects
210 	 * by their subsystem (primary key) and order (secondary key).
211 	 *
212 	 * Since some things care about execution order, this is the operation
213 	 * which ensures continued function.
214 	 */
215 	for (sipp = start; sipp < stop; sipp++) {
216 		for (xipp = sipp + 1; xipp < stop; xipp++) {
217 			if ((*sipp)->subsystem > (*xipp)->subsystem ||
218 			    ((*sipp)->subsystem == (*xipp)->subsystem &&
219 			    (*sipp)->order >= (*xipp)->order))
220 				continue;	/* skip */
221 			save = *sipp;
222 			*sipp = *xipp;
223 			*xipp = save;
224 		}
225 	}
226 
227 	/*
228 	 * Traverse the (now) ordered list of system initialization tasks.
229 	 * Perform each task, and continue on to the next task.
230 	 */
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 }
239 
240 static void
241 linker_file_register_sysctls(linker_file_t lf)
242 {
243 	struct sysctl_oid **start, **stop, **oidp;
244 
245 	KLD_DPF(FILE,
246 	    ("linker_file_register_sysctls: registering SYSCTLs for %s\n",
247 	    lf->filename));
248 
249 	if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
250 		return;
251 
252 	for (oidp = start; oidp < stop; oidp++)
253 		sysctl_register_oid(*oidp);
254 }
255 
256 static void
257 linker_file_unregister_sysctls(linker_file_t lf)
258 {
259 	struct sysctl_oid **start, **stop, **oidp;
260 
261 	KLD_DPF(FILE, ("linker_file_unregister_sysctls: registering SYSCTLs"
262 	    " for %s\n", lf->filename));
263 
264 	if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
265 		return;
266 
267 	for (oidp = start; oidp < stop; oidp++)
268 		sysctl_unregister_oid(*oidp);
269 }
270 
271 static int
272 linker_file_register_modules(linker_file_t lf)
273 {
274 	struct mod_metadata **start, **stop, **mdp;
275 	const moduledata_t *moddata;
276 	int error;
277 
278 	KLD_DPF(FILE, ("linker_file_register_modules: registering modules"
279 	    " in %s\n", lf->filename));
280 
281 	if (linker_file_lookup_set(lf, "modmetadata_set", &start,
282 	    &stop, 0) != 0) {
283 		/*
284 		 * This fallback should be unnecessary, but if we get booted
285 		 * from boot2 instead of loader and we are missing our
286 		 * metadata then we have to try the best we can.
287 		 */
288 		if (lf == linker_kernel_file) {
289 			start = SET_BEGIN(modmetadata_set);
290 			stop = SET_LIMIT(modmetadata_set);
291 		} else
292 			return (0);
293 	}
294 	for (mdp = start; mdp < stop; mdp++) {
295 		if ((*mdp)->md_type != MDT_MODULE)
296 			continue;
297 		moddata = (*mdp)->md_data;
298 		KLD_DPF(FILE, ("Registering module %s in %s\n",
299 		    moddata->name, lf->filename));
300 		error = module_register(moddata, lf);
301 		if (error)
302 			printf("Module %s failed to register: %d\n",
303 			    moddata->name, error);
304 	}
305 	return (0);
306 }
307 
308 static void
309 linker_init_kernel_modules(void)
310 {
311 
312 	linker_file_register_modules(linker_kernel_file);
313 }
314 
315 SYSINIT(linker_kernel, SI_SUB_KLD, SI_ORDER_ANY, linker_init_kernel_modules, 0)
316 
317 static int
318 linker_load_file(const char *filename, linker_file_t *result)
319 {
320 	linker_class_t lc;
321 	linker_file_t lf;
322 	int foundfile, error = 0;
323 
324 	/* Refuse to load modules if securelevel raised */
325 	if (securelevel > 0)
326 		return (EPERM);
327 
328 	lf = linker_find_file_by_name(filename);
329 	if (lf) {
330 		KLD_DPF(FILE, ("linker_load_file: file %s is already loaded,"
331 		    " incrementing refs\n", filename));
332 		*result = lf;
333 		lf->refs++;
334 		goto out;
335 	}
336 	lf = NULL;
337 	foundfile = 0;
338 
339 	/*
340 	 * We do not need to protect (lock) classes here because there is
341 	 * no class registration past startup (SI_SUB_KLD, SI_ORDER_ANY)
342 	 * and there is no class deregistration mechanism at this time.
343 	 */
344 	TAILQ_FOREACH(lc, &classes, link) {
345 		KLD_DPF(FILE, ("linker_load_file: trying to load %s\n",
346 		    filename));
347 		error = LINKER_LOAD_FILE(lc, filename, &lf);
348 		/*
349 		 * If we got something other than ENOENT, then it exists but
350 		 * we cannot load it for some other reason.
351 		 */
352 		if (error != ENOENT)
353 			foundfile = 1;
354 		if (lf) {
355 			linker_file_register_modules(lf);
356 			linker_file_register_sysctls(lf);
357 			linker_file_sysinit(lf);
358 			lf->flags |= LINKER_FILE_LINKED;
359 			*result = lf;
360 			error = 0;
361 			goto out;
362 		}
363 	}
364 	/*
365 	 * Less than ideal, but tells the user whether it failed to load or
366 	 * the module was not found.
367 	 */
368 	if (foundfile) {
369 		/*
370 		 * Format not recognized or otherwise unloadable.
371 		 * When loading a module that is statically built into
372 		 * the kernel EEXIST percolates back up as the return
373 		 * value.  Preserve this so that apps like sysinstall
374 		 * can recognize this special case and not post bogus
375 		 * dialog boxes.
376 		 */
377 		if (error != EEXIST)
378 			error = ENOEXEC;
379 	} else
380 		error = ENOENT;		/* Nothing found */
381 out:
382 	return (error);
383 }
384 
385 int
386 linker_reference_module(const char *modname, struct mod_depend *verinfo,
387     linker_file_t *result)
388 {
389 	modlist_t mod;
390 
391 	if ((mod = modlist_lookup2(modname, verinfo)) != NULL) {
392 		*result = mod->container;
393 		(*result)->refs++;
394 		return (0);
395 	}
396 
397 	return (linker_load_module(NULL, modname, NULL, verinfo, result));
398 }
399 
400 linker_file_t
401 linker_find_file_by_name(const char *filename)
402 {
403 	linker_file_t lf = 0;
404 	char *koname;
405 
406 	koname = malloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
407 	if (koname == NULL)
408 		goto out;
409 	sprintf(koname, "%s.ko", filename);
410 
411 	mtx_lock(&kld_mtx);
412 	TAILQ_FOREACH(lf, &linker_files, link) {
413 		if (strcmp(lf->filename, koname) == 0)
414 			break;
415 		if (strcmp(lf->filename, filename) == 0)
416 			break;
417 	}
418 	mtx_unlock(&kld_mtx);
419 out:
420 	if (koname)
421 		free(koname, M_LINKER);
422 	return (lf);
423 }
424 
425 linker_file_t
426 linker_find_file_by_id(int fileid)
427 {
428 	linker_file_t lf = 0;
429 
430 	mtx_lock(&kld_mtx);
431 	TAILQ_FOREACH(lf, &linker_files, link)
432 		if (lf->id == fileid)
433 			break;
434 	mtx_unlock(&kld_mtx);
435 	return (lf);
436 }
437 
438 linker_file_t
439 linker_make_file(const char *pathname, linker_class_t lc)
440 {
441 	linker_file_t lf;
442 	const char *filename;
443 
444 	lf = NULL;
445 	filename = linker_basename(pathname);
446 
447 	KLD_DPF(FILE, ("linker_make_file: new file, filename=%s\n", filename));
448 	lf = (linker_file_t)kobj_create((kobj_class_t)lc, M_LINKER, M_WAITOK);
449 	if (lf == NULL)
450 		goto out;
451 	lf->refs = 1;
452 	lf->userrefs = 0;
453 	lf->flags = 0;
454 	lf->filename = linker_strdup(filename);
455 	LINKER_GET_NEXT_FILE_ID(lf->id);
456 	lf->ndeps = 0;
457 	lf->deps = NULL;
458 	STAILQ_INIT(&lf->common);
459 	TAILQ_INIT(&lf->modules);
460 	mtx_lock(&kld_mtx);
461 	TAILQ_INSERT_TAIL(&linker_files, lf, link);
462 	mtx_unlock(&kld_mtx);
463 out:
464 	return (lf);
465 }
466 
467 int
468 linker_file_unload(linker_file_t file)
469 {
470 	module_t mod, next;
471 	modlist_t ml, nextml;
472 	struct common_symbol *cp;
473 	int error, i;
474 
475 	error = 0;
476 
477 	/* Refuse to unload modules if securelevel raised. */
478 	if (securelevel > 0)
479 		return (EPERM);
480 #ifdef MAC
481 	error = mac_check_kld_unload(curthread->td_ucred);
482 	if (error)
483 		return (error);
484 #endif
485 
486 	KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
487 	if (file->refs == 1) {
488 		KLD_DPF(FILE, ("linker_file_unload: file is unloading,"
489 		    " informing modules\n"));
490 
491 		/*
492 		 * Inform any modules associated with this file.
493 		 */
494 		MOD_XLOCK;
495 		for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
496 			next = module_getfnext(mod);
497 			MOD_XUNLOCK;
498 
499 			/*
500 			 * Give the module a chance to veto the unload.
501 			 */
502 			if ((error = module_unload(mod)) != 0) {
503 				KLD_DPF(FILE, ("linker_file_unload: module %p"
504 				    " vetoes unload\n", mod));
505 				goto out;
506 			} else
507 				MOD_XLOCK;
508 			module_release(mod);
509 		}
510 		MOD_XUNLOCK;
511 	}
512 	file->refs--;
513 	if (file->refs > 0) {
514 		goto out;
515 	}
516 	for (ml = TAILQ_FIRST(&found_modules); ml; ml = nextml) {
517 		nextml = TAILQ_NEXT(ml, link);
518 		if (ml->container == file)
519 			TAILQ_REMOVE(&found_modules, ml, link);
520 	}
521 
522 	/*
523 	 * Don't try to run SYSUNINITs if we are unloaded due to a
524 	 * link error.
525 	 */
526 	if (file->flags & LINKER_FILE_LINKED) {
527 		linker_file_sysuninit(file);
528 		linker_file_unregister_sysctls(file);
529 	}
530 	mtx_lock(&kld_mtx);
531 	TAILQ_REMOVE(&linker_files, file, link);
532 	mtx_unlock(&kld_mtx);
533 
534 	if (file->deps) {
535 		for (i = 0; i < file->ndeps; i++)
536 			linker_file_unload(file->deps[i]);
537 		free(file->deps, M_LINKER);
538 		file->deps = NULL;
539 	}
540 	for (cp = STAILQ_FIRST(&file->common); cp;
541 	    cp = STAILQ_FIRST(&file->common)) {
542 		STAILQ_REMOVE(&file->common, cp, common_symbol, link);
543 		free(cp, M_LINKER);
544 	}
545 
546 	LINKER_UNLOAD(file);
547 	if (file->filename) {
548 		free(file->filename, M_LINKER);
549 		file->filename = NULL;
550 	}
551 	kobj_delete((kobj_t) file, M_LINKER);
552 out:
553 	return (error);
554 }
555 
556 int
557 linker_file_add_dependency(linker_file_t file, linker_file_t dep)
558 {
559 	linker_file_t *newdeps;
560 
561 	newdeps = malloc((file->ndeps + 1) * sizeof(linker_file_t *),
562 	    M_LINKER, M_WAITOK | M_ZERO);
563 	if (newdeps == NULL)
564 		return (ENOMEM);
565 
566 	if (file->deps) {
567 		bcopy(file->deps, newdeps,
568 		    file->ndeps * sizeof(linker_file_t *));
569 		free(file->deps, M_LINKER);
570 	}
571 	file->deps = newdeps;
572 	file->deps[file->ndeps] = dep;
573 	file->ndeps++;
574 	return (0);
575 }
576 
577 /*
578  * Locate a linker set and its contents.  This is a helper function to avoid
579  * linker_if.h exposure elsewhere.  Note: firstp and lastp are really void ***
580  */
581 int
582 linker_file_lookup_set(linker_file_t file, const char *name,
583     void *firstp, void *lastp, int *countp)
584 {
585 
586 	return (LINKER_LOOKUP_SET(file, name, firstp, lastp, countp));
587 }
588 
589 caddr_t
590 linker_file_lookup_symbol(linker_file_t file, const char *name, int deps)
591 {
592 	c_linker_sym_t sym;
593 	linker_symval_t symval;
594 	caddr_t address;
595 	size_t common_size = 0;
596 	int i;
597 
598 	KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n",
599 	    file, name, deps));
600 
601 	if (LINKER_LOOKUP_SYMBOL(file, name, &sym) == 0) {
602 		LINKER_SYMBOL_VALUES(file, sym, &symval);
603 		if (symval.value == 0)
604 			/*
605 			 * For commons, first look them up in the
606 			 * dependencies and only allocate space if not found
607 			 * there.
608 			 */
609 			common_size = symval.size;
610 		else {
611 			KLD_DPF(SYM, ("linker_file_lookup_symbol: symbol"
612 			    ".value=%p\n", symval.value));
613 			return (symval.value);
614 		}
615 	}
616 	if (deps) {
617 		for (i = 0; i < file->ndeps; i++) {
618 			address = linker_file_lookup_symbol(file->deps[i],
619 			    name, 0);
620 			if (address) {
621 				KLD_DPF(SYM, ("linker_file_lookup_symbol:"
622 				    " deps value=%p\n", address));
623 				return (address);
624 			}
625 		}
626 	}
627 	if (common_size > 0) {
628 		/*
629 		 * This is a common symbol which was not found in the
630 		 * dependencies.  We maintain a simple common symbol table in
631 		 * the file object.
632 		 */
633 		struct common_symbol *cp;
634 
635 		STAILQ_FOREACH(cp, &file->common, link) {
636 			if (strcmp(cp->name, name) == 0) {
637 				KLD_DPF(SYM, ("linker_file_lookup_symbol:"
638 				    " old common value=%p\n", cp->address));
639 				return (cp->address);
640 			}
641 		}
642 		/*
643 		 * Round the symbol size up to align.
644 		 */
645 		common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
646 		cp = malloc(sizeof(struct common_symbol)
647 		    + common_size + strlen(name) + 1, M_LINKER,
648 		    M_WAITOK | M_ZERO);
649 		if (cp == NULL) {
650 			KLD_DPF(SYM, ("linker_file_lookup_symbol: nomem\n"));
651 			return (0);
652 		}
653 		cp->address = (caddr_t)(cp + 1);
654 		cp->name = cp->address + common_size;
655 		strcpy(cp->name, name);
656 		bzero(cp->address, common_size);
657 		STAILQ_INSERT_TAIL(&file->common, cp, link);
658 
659 		KLD_DPF(SYM, ("linker_file_lookup_symbol: new common"
660 		    " value=%p\n", cp->address));
661 		return (cp->address);
662 	}
663 	KLD_DPF(SYM, ("linker_file_lookup_symbol: fail\n"));
664 	return (0);
665 }
666 
667 #ifdef DDB
668 /*
669  * DDB Helpers.  DDB has to look across multiple files with their own symbol
670  * tables and string tables.
671  *
672  * Note that we do not obey list locking protocols here.  We really don't need
673  * DDB to hang because somebody's got the lock held.  We'll take the chance
674  * that the files list is inconsistant instead.
675  */
676 
677 int
678 linker_ddb_lookup(const char *symstr, c_linker_sym_t *sym)
679 {
680 	linker_file_t lf;
681 
682 	TAILQ_FOREACH(lf, &linker_files, link) {
683 		if (LINKER_LOOKUP_SYMBOL(lf, symstr, sym) == 0)
684 			return (0);
685 	}
686 	return (ENOENT);
687 }
688 
689 int
690 linker_ddb_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
691 {
692 	linker_file_t lf;
693 	c_linker_sym_t best, es;
694 	u_long diff, bestdiff, off;
695 
696 	best = 0;
697 	off = (uintptr_t)value;
698 	bestdiff = off;
699 	TAILQ_FOREACH(lf, &linker_files, link) {
700 		if (LINKER_SEARCH_SYMBOL(lf, value, &es, &diff) != 0)
701 			continue;
702 		if (es != 0 && diff < bestdiff) {
703 			best = es;
704 			bestdiff = diff;
705 		}
706 		if (bestdiff == 0)
707 			break;
708 	}
709 	if (best) {
710 		*sym = best;
711 		*diffp = bestdiff;
712 		return (0);
713 	} else {
714 		*sym = 0;
715 		*diffp = off;
716 		return (ENOENT);
717 	}
718 }
719 
720 int
721 linker_ddb_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
722 {
723 	linker_file_t lf;
724 
725 	TAILQ_FOREACH(lf, &linker_files, link) {
726 		if (LINKER_SYMBOL_VALUES(lf, sym, symval) == 0)
727 			return (0);
728 	}
729 	return (ENOENT);
730 }
731 #endif
732 
733 /*
734  * Syscalls.
735  */
736 /*
737  * MPSAFE
738  */
739 int
740 kldload(struct thread *td, struct kldload_args *uap)
741 {
742 	char *kldname, *modname;
743 	char *pathname = NULL;
744 	linker_file_t lf;
745 	int error = 0;
746 
747 	td->td_retval[0] = -1;
748 
749 	mtx_lock(&Giant);
750 
751 	if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
752 		goto out;
753 
754 	if ((error = suser(td)) != 0)
755 		goto out;
756 
757 	pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
758 	if ((error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL)) != 0)
759 		goto out;
760 
761 	/*
762 	 * If path do not contain qualified name or any dot in it
763 	 * (kldname.ko, or kldname.ver.ko) treat it as interface
764 	 * name.
765 	 */
766 	if (index(pathname, '/') || index(pathname, '.')) {
767 		kldname = pathname;
768 		modname = NULL;
769 	} else {
770 		kldname = NULL;
771 		modname = pathname;
772 	}
773 	error = linker_load_module(kldname, modname, NULL, NULL, &lf);
774 	if (error)
775 		goto out;
776 
777 	lf->userrefs++;
778 	td->td_retval[0] = lf->id;
779 out:
780 	if (pathname)
781 		free(pathname, M_TEMP);
782 	mtx_unlock(&Giant);
783 	return (error);
784 }
785 
786 /*
787  * MPSAFE
788  */
789 int
790 kldunload(struct thread *td, struct kldunload_args *uap)
791 {
792 	linker_file_t lf;
793 	int error = 0;
794 
795 	mtx_lock(&Giant);
796 
797 	if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
798 		goto out;
799 
800 	if ((error = suser(td)) != 0)
801 		goto out;
802 
803 	lf = linker_find_file_by_id(uap->fileid);
804 	if (lf) {
805 		KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
806 		if (lf->userrefs == 0) {
807 			printf("kldunload: attempt to unload file that was"
808 			    " loaded by the kernel\n");
809 			error = EBUSY;
810 			goto out;
811 		}
812 		lf->userrefs--;
813 		error = linker_file_unload(lf);
814 		if (error)
815 			lf->userrefs++;
816 	} else
817 		error = ENOENT;
818 out:
819 	mtx_unlock(&Giant);
820 	return (error);
821 }
822 
823 /*
824  * MPSAFE
825  */
826 int
827 kldfind(struct thread *td, struct kldfind_args *uap)
828 {
829 	char *pathname;
830 	const char *filename;
831 	linker_file_t lf;
832 	int error = 0;
833 
834 #ifdef MAC
835 	error = mac_check_kld_stat(td->td_ucred);
836 	if (error)
837 		return (error);
838 #endif
839 
840 	mtx_lock(&Giant);
841 	td->td_retval[0] = -1;
842 
843 	pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
844 	if ((error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL)) != 0)
845 		goto out;
846 
847 	filename = linker_basename(pathname);
848 	lf = linker_find_file_by_name(filename);
849 	if (lf)
850 		td->td_retval[0] = lf->id;
851 	else
852 		error = ENOENT;
853 out:
854 	if (pathname)
855 		free(pathname, M_TEMP);
856 	mtx_unlock(&Giant);
857 	return (error);
858 }
859 
860 /*
861  * MPSAFE
862  */
863 int
864 kldnext(struct thread *td, struct kldnext_args *uap)
865 {
866 	linker_file_t lf;
867 	int error = 0;
868 
869 #ifdef MAC
870 	error = mac_check_kld_stat(td->td_ucred);
871 	if (error)
872 		return (error);
873 #endif
874 
875 	mtx_lock(&Giant);
876 
877 	if (uap->fileid == 0) {
878 		mtx_lock(&kld_mtx);
879 		if (TAILQ_FIRST(&linker_files))
880 			td->td_retval[0] = TAILQ_FIRST(&linker_files)->id;
881 		else
882 			td->td_retval[0] = 0;
883 		mtx_unlock(&kld_mtx);
884 		goto out;
885 	}
886 	lf = linker_find_file_by_id(uap->fileid);
887 	if (lf) {
888 		if (TAILQ_NEXT(lf, link))
889 			td->td_retval[0] = TAILQ_NEXT(lf, link)->id;
890 		else
891 			td->td_retval[0] = 0;
892 	} else
893 		error = ENOENT;
894 out:
895 	mtx_unlock(&Giant);
896 	return (error);
897 }
898 
899 /*
900  * MPSAFE
901  */
902 int
903 kldstat(struct thread *td, struct kldstat_args *uap)
904 {
905 	linker_file_t lf;
906 	int error = 0;
907 	int namelen, version;
908 	struct kld_file_stat *stat;
909 
910 #ifdef MAC
911 	error = mac_check_kld_stat(td->td_ucred);
912 	if (error)
913 		return (error);
914 #endif
915 
916 	mtx_lock(&Giant);
917 
918 	lf = linker_find_file_by_id(uap->fileid);
919 	if (lf == NULL) {
920 		error = ENOENT;
921 		goto out;
922 	}
923 	stat = uap->stat;
924 
925 	/*
926 	 * Check the version of the user's structure.
927 	 */
928 	if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
929 		goto out;
930 	if (version != sizeof(struct kld_file_stat)) {
931 		error = EINVAL;
932 		goto out;
933 	}
934 	namelen = strlen(lf->filename) + 1;
935 	if (namelen > MAXPATHLEN)
936 		namelen = MAXPATHLEN;
937 	if ((error = copyout(lf->filename, &stat->name[0], namelen)) != 0)
938 		goto out;
939 	if ((error = copyout(&lf->refs, &stat->refs, sizeof(int))) != 0)
940 		goto out;
941 	if ((error = copyout(&lf->id, &stat->id, sizeof(int))) != 0)
942 		goto out;
943 	if ((error = copyout(&lf->address, &stat->address,
944 	    sizeof(caddr_t))) != 0)
945 		goto out;
946 	if ((error = copyout(&lf->size, &stat->size, sizeof(size_t))) != 0)
947 		goto out;
948 
949 	td->td_retval[0] = 0;
950 out:
951 	mtx_unlock(&Giant);
952 	return (error);
953 }
954 
955 /*
956  * MPSAFE
957  */
958 int
959 kldfirstmod(struct thread *td, struct kldfirstmod_args *uap)
960 {
961 	linker_file_t lf;
962 	module_t mp;
963 	int error = 0;
964 
965 #ifdef MAC
966 	error = mac_check_kld_stat(td->td_ucred);
967 	if (error)
968 		return (error);
969 #endif
970 
971 	mtx_lock(&Giant);
972 	lf = linker_find_file_by_id(uap->fileid);
973 	if (lf) {
974 		MOD_SLOCK;
975 		mp = TAILQ_FIRST(&lf->modules);
976 		if (mp != NULL)
977 			td->td_retval[0] = module_getid(mp);
978 		else
979 			td->td_retval[0] = 0;
980 		MOD_SUNLOCK;
981 	} else
982 		error = ENOENT;
983 	mtx_unlock(&Giant);
984 	return (error);
985 }
986 
987 /*
988  * MPSAFE
989  */
990 int
991 kldsym(struct thread *td, struct kldsym_args *uap)
992 {
993 	char *symstr = NULL;
994 	c_linker_sym_t sym;
995 	linker_symval_t symval;
996 	linker_file_t lf;
997 	struct kld_sym_lookup lookup;
998 	int error = 0;
999 
1000 #ifdef MAC
1001 	error = mac_check_kld_stat(td->td_ucred);
1002 	if (error)
1003 		return (error);
1004 #endif
1005 
1006 	mtx_lock(&Giant);
1007 
1008 	if ((error = copyin(uap->data, &lookup, sizeof(lookup))) != 0)
1009 		goto out;
1010 	if (lookup.version != sizeof(lookup) ||
1011 	    uap->cmd != KLDSYM_LOOKUP) {
1012 		error = EINVAL;
1013 		goto out;
1014 	}
1015 	symstr = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1016 	if ((error = copyinstr(lookup.symname, symstr, MAXPATHLEN, NULL)) != 0)
1017 		goto out;
1018 	if (uap->fileid != 0) {
1019 		lf = linker_find_file_by_id(uap->fileid);
1020 		if (lf == NULL) {
1021 			error = ENOENT;
1022 			goto out;
1023 		}
1024 		if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
1025 		    LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
1026 			lookup.symvalue = (uintptr_t) symval.value;
1027 			lookup.symsize = symval.size;
1028 			error = copyout(&lookup, uap->data, sizeof(lookup));
1029 		} else
1030 			error = ENOENT;
1031 	} else {
1032 		mtx_lock(&kld_mtx);
1033 		TAILQ_FOREACH(lf, &linker_files, link) {
1034 			if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
1035 			    LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
1036 				lookup.symvalue = (uintptr_t)symval.value;
1037 				lookup.symsize = symval.size;
1038 				error = copyout(&lookup, uap->data,
1039 				    sizeof(lookup));
1040 				break;
1041 			}
1042 		}
1043 		mtx_unlock(&kld_mtx);
1044 		if (lf == NULL)
1045 			error = ENOENT;
1046 	}
1047 out:
1048 	if (symstr)
1049 		free(symstr, M_TEMP);
1050 	mtx_unlock(&Giant);
1051 	return (error);
1052 }
1053 
1054 /*
1055  * Preloaded module support
1056  */
1057 
1058 static modlist_t
1059 modlist_lookup(const char *name, int ver)
1060 {
1061 	modlist_t mod;
1062 
1063 	TAILQ_FOREACH(mod, &found_modules, link) {
1064 		if (strcmp(mod->name, name) == 0 &&
1065 		    (ver == 0 || mod->version == ver))
1066 			return (mod);
1067 	}
1068 	return (NULL);
1069 }
1070 
1071 static modlist_t
1072 modlist_lookup2(const char *name, struct mod_depend *verinfo)
1073 {
1074 	modlist_t mod, bestmod;
1075 	int ver;
1076 
1077 	if (verinfo == NULL)
1078 		return (modlist_lookup(name, 0));
1079 	bestmod = NULL;
1080 	for (mod = TAILQ_FIRST(&found_modules); mod;
1081 	    mod = TAILQ_NEXT(mod, link)) {
1082 		if (strcmp(mod->name, name) != 0)
1083 			continue;
1084 		ver = mod->version;
1085 		if (ver == verinfo->md_ver_preferred)
1086 			return (mod);
1087 		if (ver >= verinfo->md_ver_minimum &&
1088 		    ver <= verinfo->md_ver_maximum &&
1089 		    ver > bestmod->version)
1090 			bestmod = mod;
1091 	}
1092 	return (bestmod);
1093 }
1094 
1095 static modlist_t
1096 modlist_newmodule(const char *modname, int version, linker_file_t container)
1097 {
1098 	modlist_t mod;
1099 
1100 	mod = malloc(sizeof(struct modlist), M_LINKER, M_NOWAIT | M_ZERO);
1101 	if (mod == NULL)
1102 		panic("no memory for module list");
1103 	mod->container = container;
1104 	mod->name = modname;
1105 	mod->version = version;
1106 	TAILQ_INSERT_TAIL(&found_modules, mod, link);
1107 	return (mod);
1108 }
1109 
1110 static void
1111 linker_addmodules(linker_file_t lf, struct mod_metadata **start,
1112     struct mod_metadata **stop, int preload)
1113 {
1114 	struct mod_metadata *mp, **mdp;
1115 	const char *modname;
1116 	int ver;
1117 
1118 	for (mdp = start; mdp < stop; mdp++) {
1119 		mp = *mdp;
1120 		if (mp->md_type != MDT_VERSION)
1121 			continue;
1122 		modname = mp->md_cval;
1123 		ver = ((struct mod_version *)mp->md_data)->mv_version;
1124 		if (modlist_lookup(modname, ver) != NULL) {
1125 			printf("module %s already present!\n", modname);
1126 			/* XXX what can we do? this is a build error. :-( */
1127 			continue;
1128 		}
1129 		modlist_newmodule(modname, ver, lf);
1130 	}
1131 }
1132 
1133 static void
1134 linker_preload(void *arg)
1135 {
1136 	caddr_t modptr;
1137 	const char *modname, *nmodname;
1138 	char *modtype;
1139 	linker_file_t lf;
1140 	linker_class_t lc;
1141 	int error;
1142 	linker_file_list_t loaded_files;
1143 	linker_file_list_t depended_files;
1144 	struct mod_metadata *mp, *nmp;
1145 	struct mod_metadata **start, **stop, **mdp, **nmdp;
1146 	struct mod_depend *verinfo;
1147 	int nver;
1148 	int resolves;
1149 	modlist_t mod;
1150 	struct sysinit **si_start, **si_stop;
1151 
1152 	TAILQ_INIT(&loaded_files);
1153 	TAILQ_INIT(&depended_files);
1154 	TAILQ_INIT(&found_modules);
1155 	error = 0;
1156 
1157 	modptr = NULL;
1158 	while ((modptr = preload_search_next_name(modptr)) != NULL) {
1159 		modname = (char *)preload_search_info(modptr, MODINFO_NAME);
1160 		modtype = (char *)preload_search_info(modptr, MODINFO_TYPE);
1161 		if (modname == NULL) {
1162 			printf("Preloaded module at %p does not have a"
1163 			    " name!\n", modptr);
1164 			continue;
1165 		}
1166 		if (modtype == NULL) {
1167 			printf("Preloaded module at %p does not have a type!\n",
1168 			    modptr);
1169 			continue;
1170 		}
1171 		printf("Preloaded %s \"%s\" at %p.\n", modtype, modname,
1172 		    modptr);
1173 		lf = NULL;
1174 		TAILQ_FOREACH(lc, &classes, link) {
1175 			error = LINKER_LINK_PRELOAD(lc, modname, &lf);
1176 			if (error) {
1177 				lf = NULL;
1178 				break;
1179 			}
1180 		}
1181 		if (lf)
1182 			TAILQ_INSERT_TAIL(&loaded_files, lf, loaded);
1183 	}
1184 
1185 	/*
1186 	 * First get a list of stuff in the kernel.
1187 	 */
1188 	if (linker_file_lookup_set(linker_kernel_file, MDT_SETNAME, &start,
1189 	    &stop, NULL) == 0)
1190 		linker_addmodules(linker_kernel_file, start, stop, 1);
1191 
1192 	/*
1193 	 * this is a once-off kinky bubble sort resolve relocation dependency
1194 	 * requirements
1195 	 */
1196 restart:
1197 	TAILQ_FOREACH(lf, &loaded_files, loaded) {
1198 		error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
1199 		    &stop, NULL);
1200 		/*
1201 		 * First, look to see if we would successfully link with this
1202 		 * stuff.
1203 		 */
1204 		resolves = 1;	/* unless we know otherwise */
1205 		if (!error) {
1206 			for (mdp = start; mdp < stop; mdp++) {
1207 				mp = *mdp;
1208 				if (mp->md_type != MDT_DEPEND)
1209 					continue;
1210 				modname = mp->md_cval;
1211 				verinfo = mp->md_data;
1212 				for (nmdp = start; nmdp < stop; nmdp++) {
1213 					nmp = *nmdp;
1214 					if (nmp->md_type != MDT_VERSION)
1215 						continue;
1216 					nmodname = nmp->md_cval;
1217 					if (strcmp(modname, nmodname) == 0)
1218 						break;
1219 				}
1220 				if (nmdp < stop)   /* it's a self reference */
1221 					continue;
1222 
1223 				/*
1224 				 * ok, the module isn't here yet, we
1225 				 * are not finished
1226 				 */
1227 				if (modlist_lookup2(modname, verinfo) == NULL)
1228 					resolves = 0;
1229 			}
1230 		}
1231 		/*
1232 		 * OK, if we found our modules, we can link.  So, "provide"
1233 		 * the modules inside and add it to the end of the link order
1234 		 * list.
1235 		 */
1236 		if (resolves) {
1237 			if (!error) {
1238 				for (mdp = start; mdp < stop; mdp++) {
1239 					mp = *mdp;
1240 					if (mp->md_type != MDT_VERSION)
1241 						continue;
1242 					modname = mp->md_cval;
1243 					nver = ((struct mod_version *)
1244 					    mp->md_data)->mv_version;
1245 					if (modlist_lookup(modname,
1246 					    nver) != NULL) {
1247 						printf("module %s already"
1248 						    " present!\n", modname);
1249 						linker_file_unload(lf);
1250 						TAILQ_REMOVE(&loaded_files,
1251 						    lf, loaded);
1252 						/* we changed tailq next ptr */
1253 						goto restart;
1254 					}
1255 					modlist_newmodule(modname, nver, lf);
1256 				}
1257 			}
1258 			TAILQ_REMOVE(&loaded_files, lf, loaded);
1259 			TAILQ_INSERT_TAIL(&depended_files, lf, loaded);
1260 			/*
1261 			 * Since we provided modules, we need to restart the
1262 			 * sort so that the previous files that depend on us
1263 			 * have a chance. Also, we've busted the tailq next
1264 			 * pointer with the REMOVE.
1265 			 */
1266 			goto restart;
1267 		}
1268 	}
1269 
1270 	/*
1271 	 * At this point, we check to see what could not be resolved..
1272 	 */
1273 	TAILQ_FOREACH(lf, &loaded_files, loaded) {
1274 		printf("KLD file %s is missing dependencies\n", lf->filename);
1275 		linker_file_unload(lf);
1276 		TAILQ_REMOVE(&loaded_files, lf, loaded);
1277 	}
1278 
1279 	/*
1280 	 * We made it. Finish off the linking in the order we determined.
1281 	 */
1282 	TAILQ_FOREACH(lf, &depended_files, loaded) {
1283 		if (linker_kernel_file) {
1284 			linker_kernel_file->refs++;
1285 			error = linker_file_add_dependency(lf,
1286 			    linker_kernel_file);
1287 			if (error)
1288 				panic("cannot add dependency");
1289 		}
1290 		lf->userrefs++;	/* so we can (try to) kldunload it */
1291 		error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
1292 		    &stop, NULL);
1293 		if (!error) {
1294 			for (mdp = start; mdp < stop; mdp++) {
1295 				mp = *mdp;
1296 				if (mp->md_type != MDT_DEPEND)
1297 					continue;
1298 				modname = mp->md_cval;
1299 				verinfo = mp->md_data;
1300 				mod = modlist_lookup2(modname, verinfo);
1301 				mod->container->refs++;
1302 				error = linker_file_add_dependency(lf,
1303 				    mod->container);
1304 				if (error)
1305 					panic("cannot add dependency");
1306 			}
1307 		}
1308 		/*
1309 		 * Now do relocation etc using the symbol search paths
1310 		 * established by the dependencies
1311 		 */
1312 		error = LINKER_LINK_PRELOAD_FINISH(lf);
1313 		if (error) {
1314 			printf("KLD file %s - could not finalize loading\n",
1315 			    lf->filename);
1316 			linker_file_unload(lf);
1317 			continue;
1318 		}
1319 		linker_file_register_modules(lf);
1320 		if (linker_file_lookup_set(lf, "sysinit_set", &si_start,
1321 		    &si_stop, NULL) == 0)
1322 			sysinit_add(si_start, si_stop);
1323 		linker_file_register_sysctls(lf);
1324 		lf->flags |= LINKER_FILE_LINKED;
1325 	}
1326 	/* woohoo! we made it! */
1327 }
1328 
1329 SYSINIT(preload, SI_SUB_KLD, SI_ORDER_MIDDLE, linker_preload, 0)
1330 
1331 /*
1332  * Search for a not-loaded module by name.
1333  *
1334  * Modules may be found in the following locations:
1335  *
1336  * - preloaded (result is just the module name) - on disk (result is full path
1337  * to module)
1338  *
1339  * If the module name is qualified in any way (contains path, etc.) the we
1340  * simply return a copy of it.
1341  *
1342  * The search path can be manipulated via sysctl.  Note that we use the ';'
1343  * character as a separator to be consistent with the bootloader.
1344  */
1345 
1346 static char linker_hintfile[] = "linker.hints";
1347 static char linker_path[MAXPATHLEN] = "/boot/kernel;/boot/modules";
1348 
1349 SYSCTL_STRING(_kern, OID_AUTO, module_path, CTLFLAG_RW, linker_path,
1350     sizeof(linker_path), "module load search path");
1351 
1352 TUNABLE_STR("module_path", linker_path, sizeof(linker_path));
1353 
1354 static char *linker_ext_list[] = {
1355 	"",
1356 	".ko",
1357 	NULL
1358 };
1359 
1360 /*
1361  * Check if file actually exists either with or without extension listed in
1362  * the linker_ext_list. (probably should be generic for the rest of the
1363  * kernel)
1364  */
1365 static char *
1366 linker_lookup_file(const char *path, int pathlen, const char *name,
1367     int namelen, struct vattr *vap)
1368 {
1369 	struct nameidata nd;
1370 	struct thread *td = curthread;	/* XXX */
1371 	char *result, **cpp, *sep;
1372 	int error, len, extlen, reclen, flags;
1373 	enum vtype type;
1374 
1375 	extlen = 0;
1376 	for (cpp = linker_ext_list; *cpp; cpp++) {
1377 		len = strlen(*cpp);
1378 		if (len > extlen)
1379 			extlen = len;
1380 	}
1381 	extlen++;		/* trailing '\0' */
1382 	sep = (path[pathlen - 1] != '/') ? "/" : "";
1383 
1384 	reclen = pathlen + strlen(sep) + namelen + extlen + 1;
1385 	result = malloc(reclen, M_LINKER, M_WAITOK);
1386 	for (cpp = linker_ext_list; *cpp; cpp++) {
1387 		snprintf(result, reclen, "%.*s%s%.*s%s", pathlen, path, sep,
1388 		    namelen, name, *cpp);
1389 		/*
1390 		 * Attempt to open the file, and return the path if
1391 		 * we succeed and it's a regular file.
1392 		 */
1393 		NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, result, td);
1394 		flags = FREAD;
1395 		error = vn_open(&nd, &flags, 0);
1396 		if (error == 0) {
1397 			NDFREE(&nd, NDF_ONLY_PNBUF);
1398 			type = nd.ni_vp->v_type;
1399 			if (vap)
1400 				VOP_GETATTR(nd.ni_vp, vap, td->td_ucred, td);
1401 			VOP_UNLOCK(nd.ni_vp, 0, td);
1402 			vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1403 			if (type == VREG)
1404 				return (result);
1405 		}
1406 	}
1407 	free(result, M_LINKER);
1408 	return (NULL);
1409 }
1410 
1411 #define	INT_ALIGN(base, ptr)	ptr =					\
1412 	(base) + (((ptr) - (base) + sizeof(int) - 1) & ~(sizeof(int) - 1))
1413 
1414 /*
1415  * Lookup KLD which contains requested module in the "linker.hints" file. If
1416  * version specification is available, then try to find the best KLD.
1417  * Otherwise just find the latest one.
1418  */
1419 static char *
1420 linker_hints_lookup(const char *path, int pathlen, const char *modname,
1421     int modnamelen, struct mod_depend *verinfo)
1422 {
1423 	struct thread *td = curthread;	/* XXX */
1424 	struct ucred *cred = td ? td->td_ucred : NULL;
1425 	struct nameidata nd;
1426 	struct vattr vattr, mattr;
1427 	u_char *hints = NULL;
1428 	u_char *cp, *recptr, *bufend, *result, *best, *pathbuf, *sep;
1429 	int error, ival, bestver, *intp, reclen, found, flags, clen, blen;
1430 
1431 	result = NULL;
1432 	bestver = found = 0;
1433 
1434 	sep = (path[pathlen - 1] != '/') ? "/" : "";
1435 	reclen = imax(modnamelen, strlen(linker_hintfile)) + pathlen +
1436 	    strlen(sep) + 1;
1437 	pathbuf = malloc(reclen, M_LINKER, M_WAITOK);
1438 	snprintf(pathbuf, reclen, "%.*s%s%s", pathlen, path, sep,
1439 	    linker_hintfile);
1440 
1441 	NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, pathbuf, td);
1442 	flags = FREAD;
1443 	error = vn_open(&nd, &flags, 0);
1444 	if (error)
1445 		goto bad;
1446 	NDFREE(&nd, NDF_ONLY_PNBUF);
1447 	if (nd.ni_vp->v_type != VREG)
1448 		goto bad;
1449 	best = cp = NULL;
1450 	error = VOP_GETATTR(nd.ni_vp, &vattr, cred, td);
1451 	if (error)
1452 		goto bad;
1453 	/*
1454 	 * XXX: we need to limit this number to some reasonable value
1455 	 */
1456 	if (vattr.va_size > 100 * 1024) {
1457 		printf("hints file too large %ld\n", (long)vattr.va_size);
1458 		goto bad;
1459 	}
1460 	hints = malloc(vattr.va_size, M_TEMP, M_WAITOK);
1461 	if (hints == NULL)
1462 		goto bad;
1463 	error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)hints, vattr.va_size, 0,
1464 	    UIO_SYSSPACE, IO_NODELOCKED, cred, NOCRED, &reclen, td);
1465 	if (error)
1466 		goto bad;
1467 	VOP_UNLOCK(nd.ni_vp, 0, td);
1468 	vn_close(nd.ni_vp, FREAD, cred, td);
1469 	nd.ni_vp = NULL;
1470 	if (reclen != 0) {
1471 		printf("can't read %d\n", reclen);
1472 		goto bad;
1473 	}
1474 	intp = (int *)hints;
1475 	ival = *intp++;
1476 	if (ival != LINKER_HINTS_VERSION) {
1477 		printf("hints file version mismatch %d\n", ival);
1478 		goto bad;
1479 	}
1480 	bufend = hints + vattr.va_size;
1481 	recptr = (u_char *)intp;
1482 	clen = blen = 0;
1483 	while (recptr < bufend && !found) {
1484 		intp = (int *)recptr;
1485 		reclen = *intp++;
1486 		ival = *intp++;
1487 		cp = (char *)intp;
1488 		switch (ival) {
1489 		case MDT_VERSION:
1490 			clen = *cp++;
1491 			if (clen != modnamelen || bcmp(cp, modname, clen) != 0)
1492 				break;
1493 			cp += clen;
1494 			INT_ALIGN(hints, cp);
1495 			ival = *(int *)cp;
1496 			cp += sizeof(int);
1497 			clen = *cp++;
1498 			if (verinfo == NULL ||
1499 			    ival == verinfo->md_ver_preferred) {
1500 				found = 1;
1501 				break;
1502 			}
1503 			if (ival >= verinfo->md_ver_minimum &&
1504 			    ival <= verinfo->md_ver_maximum &&
1505 			    ival > bestver) {
1506 				bestver = ival;
1507 				best = cp;
1508 				blen = clen;
1509 			}
1510 			break;
1511 		default:
1512 			break;
1513 		}
1514 		recptr += reclen + sizeof(int);
1515 	}
1516 	/*
1517 	 * Finally check if KLD is in the place
1518 	 */
1519 	if (found)
1520 		result = linker_lookup_file(path, pathlen, cp, clen, &mattr);
1521 	else if (best)
1522 		result = linker_lookup_file(path, pathlen, best, blen, &mattr);
1523 
1524 	/*
1525 	 * KLD is newer than hints file. What we should do now?
1526 	 */
1527 	if (result && timespeccmp(&mattr.va_mtime, &vattr.va_mtime, >))
1528 		printf("warning: KLD '%s' is newer than the linker.hints"
1529 		    " file\n", result);
1530 bad:
1531 	free(pathbuf, M_LINKER);
1532 	if (hints)
1533 		free(hints, M_TEMP);
1534 	if (nd.ni_vp != NULL) {
1535 		VOP_UNLOCK(nd.ni_vp, 0, td);
1536 		vn_close(nd.ni_vp, FREAD, cred, td);
1537 	}
1538 	/*
1539 	 * If nothing found or hints is absent - fallback to the old
1540 	 * way by using "kldname[.ko]" as module name.
1541 	 */
1542 	if (!found && !bestver && result == NULL)
1543 		result = linker_lookup_file(path, pathlen, modname,
1544 		    modnamelen, NULL);
1545 	return (result);
1546 }
1547 
1548 /*
1549  * Lookup KLD which contains requested module in the all directories.
1550  */
1551 static char *
1552 linker_search_module(const char *modname, int modnamelen,
1553     struct mod_depend *verinfo)
1554 {
1555 	char *cp, *ep, *result;
1556 
1557 	/*
1558 	 * traverse the linker path
1559 	 */
1560 	for (cp = linker_path; *cp; cp = ep + 1) {
1561 		/* find the end of this component */
1562 		for (ep = cp; (*ep != 0) && (*ep != ';'); ep++);
1563 		result = linker_hints_lookup(cp, ep - cp, modname,
1564 		    modnamelen, verinfo);
1565 		if (result != NULL)
1566 			return (result);
1567 		if (*ep == 0)
1568 			break;
1569 	}
1570 	return (NULL);
1571 }
1572 
1573 /*
1574  * Search for module in all directories listed in the linker_path.
1575  */
1576 static char *
1577 linker_search_kld(const char *name)
1578 {
1579 	char *cp, *ep, *result, **cpp;
1580 	int extlen, len;
1581 
1582 	/* qualified at all? */
1583 	if (index(name, '/'))
1584 		return (linker_strdup(name));
1585 
1586 	extlen = 0;
1587 	for (cpp = linker_ext_list; *cpp; cpp++) {
1588 		len = strlen(*cpp);
1589 		if (len > extlen)
1590 			extlen = len;
1591 	}
1592 	extlen++;		/* trailing '\0' */
1593 
1594 	/* traverse the linker path */
1595 	len = strlen(name);
1596 	for (ep = linker_path; *ep; ep++) {
1597 		cp = ep;
1598 		/* find the end of this component */
1599 		for (; *ep != 0 && *ep != ';'; ep++);
1600 		result = linker_lookup_file(cp, ep - cp, name, len, NULL);
1601 		if (result != NULL)
1602 			return (result);
1603 	}
1604 	return (NULL);
1605 }
1606 
1607 static const char *
1608 linker_basename(const char *path)
1609 {
1610 	const char *filename;
1611 
1612 	filename = rindex(path, '/');
1613 	if (filename == NULL)
1614 		return path;
1615 	if (filename[1])
1616 		filename++;
1617 	return (filename);
1618 }
1619 
1620 /*
1621  * Find a file which contains given module and load it, if "parent" is not
1622  * NULL, register a reference to it.
1623  */
1624 int
1625 linker_load_module(const char *kldname, const char *modname,
1626     struct linker_file *parent, struct mod_depend *verinfo,
1627     struct linker_file **lfpp)
1628 {
1629 	linker_file_t lfdep;
1630 	const char *filename;
1631 	char *pathname;
1632 	int error;
1633 
1634 	if (modname == NULL) {
1635 		/*
1636  		 * We have to load KLD
1637  		 */
1638 		KASSERT(verinfo == NULL, ("linker_load_module: verinfo"
1639 		    " is not NULL"));
1640 		pathname = linker_search_kld(kldname);
1641 	} else {
1642 		if (modlist_lookup2(modname, verinfo) != NULL)
1643 			return (EEXIST);
1644 		if (kldname != NULL)
1645 			pathname = linker_strdup(kldname);
1646 		else if (rootvnode == NULL)
1647 			pathname = NULL;
1648 		else
1649 			/*
1650 			 * Need to find a KLD with required module
1651 			 */
1652 			pathname = linker_search_module(modname,
1653 			    strlen(modname), verinfo);
1654 	}
1655 	if (pathname == NULL)
1656 		return (ENOENT);
1657 
1658 	/*
1659 	 * Can't load more than one file with the same basename XXX:
1660 	 * Actually it should be possible to have multiple KLDs with
1661 	 * the same basename but different path because they can
1662 	 * provide different versions of the same modules.
1663 	 */
1664 	filename = linker_basename(pathname);
1665 	if (linker_find_file_by_name(filename)) {
1666 		error = EEXIST;
1667 		goto out;
1668 	}
1669 	do {
1670 		error = linker_load_file(pathname, &lfdep);
1671 		if (error)
1672 			break;
1673 		if (modname && verinfo &&
1674 		    modlist_lookup2(modname, verinfo) == NULL) {
1675 			linker_file_unload(lfdep);
1676 			error = ENOENT;
1677 			break;
1678 		}
1679 		if (parent) {
1680 			error = linker_file_add_dependency(parent, lfdep);
1681 			if (error)
1682 				break;
1683 		}
1684 		if (lfpp)
1685 			*lfpp = lfdep;
1686 	} while (0);
1687 out:
1688 	if (pathname)
1689 		free(pathname, M_LINKER);
1690 	return (error);
1691 }
1692 
1693 /*
1694  * This routine is responsible for finding dependencies of userland initiated
1695  * kldload(2)'s of files.
1696  */
1697 int
1698 linker_load_dependencies(linker_file_t lf)
1699 {
1700 	linker_file_t lfdep;
1701 	struct mod_metadata **start, **stop, **mdp, **nmdp;
1702 	struct mod_metadata *mp, *nmp;
1703 	struct mod_depend *verinfo;
1704 	modlist_t mod;
1705 	const char *modname, *nmodname;
1706 	int ver, error = 0, count;
1707 
1708 	/*
1709 	 * All files are dependant on /kernel.
1710 	 */
1711 	if (linker_kernel_file) {
1712 		linker_kernel_file->refs++;
1713 		error = linker_file_add_dependency(lf, linker_kernel_file);
1714 		if (error)
1715 			return (error);
1716 	}
1717 	if (linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop,
1718 	    &count) != 0)
1719 		return (0);
1720 	for (mdp = start; mdp < stop; mdp++) {
1721 		mp = *mdp;
1722 		if (mp->md_type != MDT_VERSION)
1723 			continue;
1724 		modname = mp->md_cval;
1725 		ver = ((struct mod_version *)mp->md_data)->mv_version;
1726 		mod = modlist_lookup(modname, ver);
1727 		if (mod != NULL) {
1728 			printf("interface %s.%d already present in the KLD"
1729 			    " '%s'!\n", modname, ver,
1730 			    mod->container->filename);
1731 			return (EEXIST);
1732 		}
1733 	}
1734 
1735 	for (mdp = start; mdp < stop; mdp++) {
1736 		mp = *mdp;
1737 		if (mp->md_type != MDT_DEPEND)
1738 			continue;
1739 		modname = mp->md_cval;
1740 		verinfo = mp->md_data;
1741 		nmodname = NULL;
1742 		for (nmdp = start; nmdp < stop; nmdp++) {
1743 			nmp = *nmdp;
1744 			if (nmp->md_type != MDT_VERSION)
1745 				continue;
1746 			nmodname = nmp->md_cval;
1747 			if (strcmp(modname, nmodname) == 0)
1748 				break;
1749 		}
1750 		if (nmdp < stop)/* early exit, it's a self reference */
1751 			continue;
1752 		mod = modlist_lookup2(modname, verinfo);
1753 		if (mod) {	/* woohoo, it's loaded already */
1754 			lfdep = mod->container;
1755 			lfdep->refs++;
1756 			error = linker_file_add_dependency(lf, lfdep);
1757 			if (error)
1758 				break;
1759 			continue;
1760 		}
1761 		error = linker_load_module(NULL, modname, lf, verinfo, NULL);
1762 		if (error) {
1763 			printf("KLD %s: depends on %s - not available\n",
1764 			    lf->filename, modname);
1765 			break;
1766 		}
1767 	}
1768 
1769 	if (error)
1770 		return (error);
1771 	linker_addmodules(lf, start, stop, 0);
1772 	return (error);
1773 }
1774 
1775 static int
1776 sysctl_kern_function_list_iterate(const char *name, void *opaque)
1777 {
1778 	struct sysctl_req *req;
1779 
1780 	req = opaque;
1781 	return (SYSCTL_OUT(req, name, strlen(name) + 1));
1782 }
1783 
1784 /*
1785  * Export a nul-separated, double-nul-terminated list of all function names
1786  * in the kernel.
1787  */
1788 static int
1789 sysctl_kern_function_list(SYSCTL_HANDLER_ARGS)
1790 {
1791 	linker_file_t lf;
1792 	int error;
1793 
1794 #ifdef MAC
1795 	error = mac_check_kld_stat(req->td->td_ucred);
1796 	if (error)
1797 		return (error);
1798 #endif
1799 	sysctl_wire_old_buffer(req, 0);
1800 	mtx_lock(&kld_mtx);
1801 	TAILQ_FOREACH(lf, &linker_files, link) {
1802 		error = LINKER_EACH_FUNCTION_NAME(lf,
1803 		    sysctl_kern_function_list_iterate, req);
1804 		if (error) {
1805 			mtx_unlock(&kld_mtx);
1806 			return (error);
1807 		}
1808 	}
1809 	mtx_unlock(&kld_mtx);
1810 	return (SYSCTL_OUT(req, "", 1));
1811 }
1812 
1813 SYSCTL_PROC(_kern, OID_AUTO, function_list, CTLFLAG_RD,
1814     NULL, 0, sysctl_kern_function_list, "", "kernel function list");
1815