xref: /dragonfly/sys/kern/kern_linker.c (revision 22cd51fe)
1 /*-
2  * Copyright (c) 1997 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  * $FreeBSD: src/sys/kern/kern_linker.c,v 1.41.2.3 2001/11/21 17:50:35 luigi Exp $
27  */
28 
29 #include "opt_ddb.h"
30 
31 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/systm.h>
34 #include <sys/malloc.h>
35 #include <sys/sysmsg.h>
36 #include <sys/sysent.h>
37 #include <sys/proc.h>
38 #include <sys/priv.h>
39 #include <sys/lock.h>
40 #include <sys/module.h>
41 #include <sys/queue.h>
42 #include <sys/linker.h>
43 #include <sys/fcntl.h>
44 #include <sys/libkern.h>
45 #include <sys/nlookup.h>
46 #include <sys/vnode.h>
47 #include <sys/sysctl.h>
48 
49 #include <vm/vm_zone.h>
50 
51 #ifdef _KERNEL_VIRTUAL
52 #include <dlfcn.h>
53 #endif
54 
55 #ifdef KLD_DEBUG
56 int kld_debug = 1;
57 #endif
58 
59 /* Metadata from the static kernel */
60 SET_DECLARE(modmetadata_set, struct mod_metadata);
61 MALLOC_DEFINE(M_LINKER, "kld", "kernel linker");
62 
63 linker_file_t linker_current_file;
64 linker_file_t linker_kernel_file;
65 
66 static struct lock llf_lock;	/* lock for the file list */
67 static struct lock kld_lock;
68 static linker_class_list_t classes;
69 static linker_file_list_t linker_files;
70 static int next_file_id = 1;
71 
72 /* XXX wrong name; we're looking at version provision tags here, not modules */
73 typedef TAILQ_HEAD(, modlist) modlisthead_t;
74 struct modlist {
75 	TAILQ_ENTRY(modlist) link;	/* chain together all modules */
76 	linker_file_t   container;
77 	const char 	*name;
78 	int             version;
79 };
80 typedef struct modlist *modlist_t;
81 static modlisthead_t found_modules;
82 
83 
84 static int linker_load_module(const char *kldname, const char *modname,
85 			      struct linker_file *parent, struct mod_depend *verinfo,
86 			      struct linker_file **lfpp);
87 
88 static char *
89 linker_strdup(const char *str)
90 {
91     char	*result;
92 
93     result = kmalloc(strlen(str) + 1, M_LINKER, M_WAITOK);
94     strcpy(result, str);
95     return(result);
96 }
97 
98 static const char *
99 linker_basename(const char *path)
100 {
101     const char	*filename;
102 
103     filename = strrchr(path, '/');
104     if (filename == NULL)
105 	return path;
106     if (filename[1])
107 	filename++;
108     return (filename);
109 }
110 
111 static void
112 linker_init(void* arg)
113 {
114     lockinit(&llf_lock, "klink", 0, 0);
115     lockinit(&kld_lock, "kldlk", 0, LK_CANRECURSE);
116     TAILQ_INIT(&classes);
117     TAILQ_INIT(&linker_files);
118 }
119 
120 SYSINIT(linker, SI_BOOT2_KLD, SI_ORDER_FIRST, linker_init, 0);
121 
122 int
123 linker_add_class(const char* desc, void* priv,
124 		 struct linker_class_ops* ops)
125 {
126     linker_class_t lc;
127 
128     lc = kmalloc(sizeof(struct linker_class), M_LINKER, M_NOWAIT | M_ZERO);
129     if (!lc)
130 	return ENOMEM;
131 
132     lc->desc = desc;
133     lc->priv = priv;
134     lc->ops = ops;
135     TAILQ_INSERT_HEAD(&classes, lc, link);
136 
137     return 0;
138 }
139 
140 static void
141 linker_file_sysinit(linker_file_t lf)
142 {
143     struct sysinit** start, ** stop;
144     struct sysinit** sipp;
145     struct sysinit** xipp;
146     struct sysinit* save;
147 
148     KLD_DPF(FILE, ("linker_file_sysinit: calling SYSINITs for %s\n",
149 		   lf->filename));
150 
151     if (linker_file_lookup_set(lf, "sysinit_set", &start, &stop, NULL) != 0)
152 	return;
153 
154     /*
155      * Perform a bubble sort of the system initialization objects by
156      * their subsystem (primary key) and order (secondary key).
157      *
158      * Since some things care about execution order, this is the
159      * operation which ensures continued function.
160      */
161     for (sipp = start; sipp < stop; sipp++) {
162 	for (xipp = sipp + 1; xipp < stop; xipp++) {
163 	    if ((*sipp)->subsystem < (*xipp)->subsystem ||
164 		 ((*sipp)->subsystem == (*xipp)->subsystem &&
165 		  (*sipp)->order <= (*xipp)->order))
166 		continue;	/* skip*/
167 	    save = *sipp;
168 	    *sipp = *xipp;
169 	    *xipp = save;
170 	}
171     }
172 
173 
174     /*
175      * Traverse the (now) ordered list of system initialization tasks.
176      * Perform each task, and continue on to the next task.
177      */
178     for (sipp = start; sipp < stop; sipp++) {
179 	if ((*sipp)->subsystem == SI_SPECIAL_DUMMY)
180 	    continue;	/* skip dummy task(s)*/
181 
182 	/* Call function */
183 	(*((*sipp)->func))((*sipp)->udata);
184     }
185 }
186 
187 static void
188 linker_file_sysuninit(linker_file_t lf)
189 {
190     struct sysinit** start, ** stop;
191     struct sysinit** sipp;
192     struct sysinit** xipp;
193     struct sysinit* save;
194 
195     KLD_DPF(FILE, ("linker_file_sysuninit: calling SYSUNINITs for %s\n",
196 		   lf->filename));
197 
198     if (linker_file_lookup_set(lf, "sysuninit_set", &start, &stop, NULL) != 0)
199 	return;
200 
201     /*
202      * Perform a reverse bubble sort of the system initialization objects
203      * by their subsystem (primary key) and order (secondary key).
204      *
205      * Since some things care about execution order, this is the
206      * operation which ensures continued function.
207      */
208     for (sipp = start; sipp < stop; sipp++) {
209 	for (xipp = sipp + 1; xipp < stop; xipp++) {
210 	    if ((*sipp)->subsystem > (*xipp)->subsystem ||
211 		 ((*sipp)->subsystem == (*xipp)->subsystem &&
212 		  (*sipp)->order >= (*xipp)->order))
213 		continue;	/* skip*/
214 	    save = *sipp;
215 	    *sipp = *xipp;
216 	    *xipp = save;
217 	}
218     }
219 
220 
221     /*
222      * Traverse the (now) ordered list of system initialization tasks.
223      * Perform each task, and continue on to the next task.
224      */
225     for (sipp = start; sipp < stop; sipp++) {
226 	if ((*sipp)->subsystem == SI_SPECIAL_DUMMY)
227 	    continue;	/* skip dummy task(s)*/
228 
229 	/* Call function */
230 	(*((*sipp)->func))((*sipp)->udata);
231     }
232 }
233 
234 static void
235 linker_file_register_sysctls(linker_file_t lf)
236 {
237     struct sysctl_oid **start, **stop, **oidp;
238 
239     KLD_DPF(FILE, ("linker_file_register_sysctls: registering SYSCTLs for %s\n",
240 		   lf->filename));
241 
242     if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
243 	return;
244     for (oidp = start; oidp < stop; oidp++)
245 	sysctl_register_oid(*oidp);
246 }
247 
248 static void
249 linker_file_unregister_sysctls(linker_file_t lf)
250 {
251     struct sysctl_oid **start, **stop, **oidp;
252 
253     KLD_DPF(FILE, ("linker_file_unregister_sysctls: registering SYSCTLs for %s\n",
254 		   lf->filename));
255 
256     if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
257 	return;
258     for (oidp = start; oidp < stop; oidp++)
259 	sysctl_unregister_oid(*oidp);
260 }
261 
262 static int
263 linker_file_register_modules(linker_file_t lf)
264 {
265     struct mod_metadata **start, **stop, **mdp;
266     const moduledata_t *moddata;
267     int		    first_error, error;
268 
269     KLD_DPF(FILE, ("linker_file_register_modules: registering modules in %s\n",
270 		   lf->filename));
271 
272     if (linker_file_lookup_set(lf, "modmetadata_set", &start, &stop, NULL) != 0) {
273 	/*
274 	 * This fallback should be unnecessary, but if we get booted
275 	 * from boot2 instead of loader and we are missing our
276 	 * metadata then we have to try the best we can.
277 	 */
278 	if (lf == linker_kernel_file) {
279 	    start = SET_BEGIN(modmetadata_set);
280 	    stop = SET_LIMIT(modmetadata_set);
281 	} else
282 	    return (0);
283     }
284     first_error = 0;
285     for (mdp = start; mdp < stop; mdp++) {
286 	if ((*mdp)->md_type != MDT_MODULE)
287 	    continue;
288 	moddata = (*mdp)->md_data;
289 	KLD_DPF(FILE, ("Registering module %s in %s\n", moddata->name, lf->filename));
290 	error = module_register(moddata, lf);
291 	if (error) {
292 	    kprintf("Module %s failed to register: %d\n", moddata->name, error);
293 	    if (first_error == 0)
294 		first_error = error;
295 	}
296     }
297     return (first_error);
298 }
299 
300 static void
301 linker_init_kernel_modules(void)
302 {
303 
304     linker_file_register_modules(linker_kernel_file);
305 }
306 
307 SYSINIT(linker_kernel, SI_BOOT2_KLD, SI_ORDER_ANY, linker_init_kernel_modules, 0);
308 
309 int
310 linker_load_file(const char *filename, linker_file_t *result)
311 {
312     linker_class_t lc;
313     linker_file_t lf;
314     int foundfile, error = 0;
315 
316     /* Refuse to load modules if securelevel raised */
317     if (securelevel > 0 || kernel_mem_readonly)
318 	return EPERM;
319 
320     lf = linker_find_file_by_name(filename);
321     if (lf) {
322 	KLD_DPF(FILE, ("linker_load_file: file %s is already loaded, incrementing refs\n", filename));
323 	*result = lf;
324 	lf->refs++;
325 	goto out;
326     }
327 
328     lf = NULL;
329     foundfile = 0;
330     TAILQ_FOREACH(lc, &classes, link) {
331 	KLD_DPF(FILE, ("linker_load_file: trying to load %s as %s\n",
332 		       filename, lc->desc));
333 
334 	error = lc->ops->load_file(filename, &lf);
335 	/*
336 	 * If we got something other than ENOENT, then it exists but we cannot
337 	 * load it for some other reason.
338 	 */
339 	if (error != ENOENT)
340 	    foundfile = 1;
341 	if (lf) {
342 	    error = linker_file_register_modules(lf);
343 	    if (error == EEXIST) {
344 		    linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */);
345 		    return (error);
346 	    }
347 	    linker_file_register_sysctls(lf);
348 	    linker_file_sysinit(lf);
349 	    lf->flags |= LINKER_FILE_LINKED;
350 	    *result = lf;
351 	    return (0);
352 	}
353     }
354     /*
355      * Less than ideal, but tells the user whether it failed to load or
356      * the module was not found.
357      */
358     if (foundfile) {
359 	    /*
360 	     * If the file type has not been recognized by the last try
361 	     * printout a message before to fail.
362 	     */
363 	    if (error == ENOSYS)
364 		    kprintf("linker_load_file: Unsupported file type\n");
365 
366 	    /*
367 	     * Format not recognized or otherwise unloadable.
368 	     * When loading a module that is statically built into
369 	     * the kernel EEXIST percolates back up as the return
370 	     * value.  Preserve this so that apps can recognize this
371 	     * special case.
372 	     */
373 	    if (error != EEXIST)
374 		    error = ENOEXEC;
375     } else {
376 	error = ENOENT;		/* Nothing found */
377     }
378 
379 out:
380     return error;
381 }
382 
383 
384 linker_file_t
385 linker_find_file_by_name(const char* filename)
386 {
387     linker_file_t lf = NULL;
388     char *koname;
389     int i;
390 
391     for (i = strlen(filename); i > 0 && filename[i-1] != '/'; --i)
392 	;
393     filename += i;
394 
395     koname = kmalloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
396     ksprintf(koname, "%s.ko", filename);
397 
398     lockmgr(&llf_lock, LK_SHARED);
399     TAILQ_FOREACH(lf, &linker_files, link) {
400 	if (!strcmp(lf->filename, koname))
401 	    break;
402 	if (!strcmp(lf->filename, filename))
403 	    break;
404     }
405     lockmgr(&llf_lock, LK_RELEASE);
406 
407     if (koname)
408 	kfree(koname, M_LINKER);
409     return lf;
410 }
411 
412 linker_file_t
413 linker_find_file_by_id(int fileid)
414 {
415     linker_file_t lf = NULL;
416 
417     lockmgr(&llf_lock, LK_SHARED);
418     TAILQ_FOREACH(lf, &linker_files, link) {
419 	if (lf->id == fileid)
420 	    break;
421     }
422     lockmgr(&llf_lock, LK_RELEASE);
423 
424     return lf;
425 }
426 
427 int
428 linker_file_foreach(linker_predicate_t *predicate, void *context)
429 {
430     linker_file_t lf;
431     int retval = 0;
432 
433     lockmgr(&llf_lock, LK_SHARED);
434     TAILQ_FOREACH(lf, &linker_files, link) {
435 	retval = predicate(lf, context);
436 	if (retval != 0)
437 	    break;
438     }
439     lockmgr(&llf_lock, LK_RELEASE);
440 
441     return (retval);
442 }
443 
444 linker_file_t
445 linker_make_file(const char* pathname, void* priv, struct linker_file_ops* ops)
446 {
447     linker_file_t lf = NULL;
448     const char *filename;
449 
450     filename = linker_basename(pathname);
451     KLD_DPF(FILE, ("linker_make_file: new file, filename=%s, pathname=%s\n",
452 		   filename, pathname));
453 
454     lockmgr(&llf_lock, LK_EXCLUSIVE);
455     lf = kmalloc(sizeof(struct linker_file), M_LINKER, M_WAITOK | M_ZERO);
456     lf->refs = 1;
457     lf->userrefs = 0;
458     lf->flags = 0;
459     lf->filename = linker_strdup(filename);
460     lf->pathname = linker_strdup(pathname);
461     lf->id = next_file_id++;
462     lf->ndeps = 0;
463     lf->deps = NULL;
464     STAILQ_INIT(&lf->common);
465     TAILQ_INIT(&lf->modules);
466 
467     lf->priv = priv;
468     lf->ops = ops;
469     TAILQ_INSERT_TAIL(&linker_files, lf, link);
470 
471     lockmgr(&llf_lock, LK_RELEASE);
472 
473     return lf;
474 }
475 
476 int
477 linker_file_unload(linker_file_t file)
478 {
479     module_t mod, next;
480     modlist_t ml, nextml;
481     struct common_symbol* cp;
482     int error = 0;
483     int i;
484 
485     /* Refuse to unload modules if securelevel raised */
486     if (securelevel > 0 || kernel_mem_readonly)
487 	return EPERM;
488 
489     KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
490 
491     lockmgr(&llf_lock, LK_EXCLUSIVE);
492 
493     /* Easy case of just dropping a reference. */
494     if (file->refs > 1) {
495 	    file->refs--;
496 	    lockmgr(&llf_lock, LK_RELEASE);
497 	    return (0);
498     }
499 
500     KLD_DPF(FILE, ("linker_file_unload: file is unloading, informing modules\n"));
501 
502     /*
503      * Inform any modules associated with this file.
504      */
505     mod = TAILQ_FIRST(&file->modules);
506     for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
507 	next = module_getfnext(mod);
508 
509 	/*
510 	 * Give the module a chance to veto the unload.  Note that the
511 	 * act of unloading the module may cause other modules in the
512 	 * same file list to be unloaded recursively.
513 	 */
514 	if ((error = module_unload(mod)) != 0) {
515 	    KLD_DPF(FILE, ("linker_file_unload: module %p vetoes unload\n",
516 			   mod));
517 	    lockmgr(&llf_lock, LK_RELEASE);
518 	    file->refs--;
519 	    goto out;
520 	}
521 	module_release(mod);
522     }
523 
524     TAILQ_FOREACH_MUTABLE(ml, &found_modules, link, nextml) {
525 	if (ml->container == file) {
526 	    TAILQ_REMOVE(&found_modules, ml, link);
527 	    kfree(ml, M_LINKER);
528 	}
529     }
530 
531     /* Don't try to run SYSUNINITs if we are unloaded due to a link error */
532     if (file->flags & LINKER_FILE_LINKED) {
533 	file->flags &= ~LINKER_FILE_LINKED;
534 	lockmgr(&llf_lock, LK_RELEASE);
535 	linker_file_sysuninit(file);
536 	linker_file_unregister_sysctls(file);
537 	lockmgr(&llf_lock, LK_EXCLUSIVE);
538     }
539 
540     TAILQ_REMOVE(&linker_files, file, link);
541 
542     if (file->deps) {
543 	lockmgr(&llf_lock, LK_RELEASE);
544 	for (i = 0; i < file->ndeps; i++)
545 	    linker_file_unload(file->deps[i]);
546 	lockmgr(&llf_lock, LK_EXCLUSIVE);
547 	kfree(file->deps, M_LINKER);
548 	file->deps = NULL;
549     }
550 
551     while ((cp = STAILQ_FIRST(&file->common)) != NULL) {
552 	STAILQ_REMOVE_HEAD(&file->common, link);
553 	kfree(cp, M_LINKER);
554     }
555 
556     file->ops->unload(file);
557 
558     if (file->filename) {
559 	kfree(file->filename, M_LINKER);
560 	file->filename = NULL;
561     }
562     if (file->pathname) {
563 	kfree(file->pathname, M_LINKER);
564 	file->pathname = NULL;
565     }
566 
567     kfree(file, M_LINKER);
568 
569     lockmgr(&llf_lock, LK_RELEASE);
570 
571 out:
572     return error;
573 }
574 
575 void
576 linker_file_add_dependancy(linker_file_t file, linker_file_t dep)
577 {
578     linker_file_t* newdeps;
579 
580     newdeps = kmalloc((file->ndeps + 1) * sizeof(linker_file_t*),
581 		     M_LINKER, M_WAITOK | M_ZERO);
582 
583     if (file->deps) {
584 	bcopy(file->deps, newdeps, file->ndeps * sizeof(linker_file_t*));
585 	kfree(file->deps, M_LINKER);
586     }
587     file->deps = newdeps;
588     file->deps[file->ndeps] = dep;
589     file->ndeps++;
590 }
591 
592 /*
593  * Locate a linker set and its contents.
594  * This is a helper function to avoid linker_if.h exposure elsewhere.
595  * Note: firstp and lastp are really void ***
596  */
597 int
598 linker_file_lookup_set(linker_file_t file, const char *name,
599                       void *firstp, void *lastp, int *countp)
600 {
601     return file->ops->lookup_set(file, name, firstp, lastp, countp);
602 }
603 
604 int
605 linker_file_lookup_symbol(linker_file_t file, const char* name, int deps, caddr_t *raddr)
606 {
607     c_linker_sym_t sym;
608     linker_symval_t symval;
609     linker_file_t lf;
610     size_t common_size = 0;
611     int i;
612 
613     KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n",
614 		  file, name, deps));
615 
616     if (file->ops->lookup_symbol(file, name, &sym) == 0) {
617 	file->ops->symbol_values(file, sym, &symval);
618 
619 	/*
620 	 * XXX Assume a common symbol if its value is 0 and it has a non-zero
621 	 * size, otherwise it could be an absolute symbol with a value of 0.
622 	 */
623 	if (symval.value == NULL && symval.size != 0) {
624 	    /*
625 	     * For commons, first look them up in the dependancies and
626 	     * only allocate space if not found there.
627 	     */
628 	    common_size = symval.size;
629 	} else {
630 	    KLD_DPF(SYM, ("linker_file_lookup_symbol: symbol.value=%p\n", symval.value));
631 	    *raddr = symval.value;
632 	    return 0;
633 	}
634     }
635     if (deps) {
636 	for (i = 0; i < file->ndeps; i++) {
637 	    if (linker_file_lookup_symbol(file->deps[i], name, 0, raddr) == 0) {
638 		KLD_DPF(SYM, ("linker_file_lookup_symbol: deps value=%p\n", *raddr));
639 		return 0;
640 	    }
641 	}
642 
643 	/* If we have not found it in the dependencies, search globally */
644 	TAILQ_FOREACH(lf, &linker_files, link) {
645 	    /* But skip the current file if it's on the list */
646 	    if (lf == file)
647 		continue;
648 	    /* And skip the files we searched above */
649 	    for (i = 0; i < file->ndeps; i++)
650 		if (lf == file->deps[i])
651 		    break;
652 	    if (i < file->ndeps)
653 		continue;
654 	    if (linker_file_lookup_symbol(lf, name, 0, raddr) == 0) {
655 		KLD_DPF(SYM, ("linker_file_lookup_symbol: global value=%p\n", *raddr));
656 		return 0;
657 	    }
658 	}
659     }
660 
661     if (common_size > 0) {
662 	/*
663 	 * This is a common symbol which was not found in the
664 	 * dependancies.  We maintain a simple common symbol table in
665 	 * the file object.
666 	 */
667 	struct common_symbol* cp;
668 
669 	STAILQ_FOREACH(cp, &file->common, link)
670 	    if (!strcmp(cp->name, name)) {
671 		KLD_DPF(SYM, ("linker_file_lookup_symbol: old common value=%p\n", cp->address));
672 		*raddr = cp->address;
673 		return 0;
674 	    }
675 
676 	/*
677 	 * Round the symbol size up to align.
678 	 */
679 	common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
680 	cp = kmalloc(sizeof(struct common_symbol)
681 		    + common_size
682 		    + strlen(name) + 1,
683 		    M_LINKER, M_WAITOK | M_ZERO);
684 
685 	cp->address = (caddr_t) (cp + 1);
686 	cp->name = cp->address + common_size;
687 	strcpy(cp->name, name);
688 	bzero(cp->address, common_size);
689 	STAILQ_INSERT_TAIL(&file->common, cp, link);
690 
691 	KLD_DPF(SYM, ("linker_file_lookup_symbol: new common value=%p\n", cp->address));
692 	*raddr = cp->address;
693 	return 0;
694     }
695 
696 #ifdef _KERNEL_VIRTUAL
697     *raddr = dlsym(RTLD_NEXT, name);
698     if (*raddr != NULL) {
699 	KLD_DPF(SYM, ("linker_file_lookup_symbol: found dlsym=%p\n", *raddr));
700 	return 0;
701     }
702 #endif
703 
704     KLD_DPF(SYM, ("linker_file_lookup_symbol: fail\n"));
705     return ENOENT;
706 }
707 
708 #ifdef DDB
709 /*
710  * DDB Helpers.  DDB has to look across multiple files with their own
711  * symbol tables and string tables.
712  *
713  * Note that we do not obey list locking protocols here.  We really don't
714  * need DDB to hang because somebody's got the lock held.  We'll take the
715  * chance that the files list is inconsistant instead.
716  */
717 
718 int
719 linker_ddb_lookup(const char *symstr, c_linker_sym_t *sym)
720 {
721     linker_file_t lf;
722 
723     TAILQ_FOREACH(lf, &linker_files, link) {
724 	if (lf->ops->lookup_symbol(lf, symstr, sym) == 0)
725 	    return 0;
726     }
727     return ENOENT;
728 }
729 
730 int
731 linker_ddb_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
732 {
733     linker_file_t lf;
734     u_long off = (uintptr_t)value;
735     u_long diff, bestdiff;
736     c_linker_sym_t best;
737     c_linker_sym_t es;
738 
739     best = NULL;
740     bestdiff = off;
741     TAILQ_FOREACH(lf, &linker_files, link) {
742 	if (lf->ops->search_symbol(lf, value, &es, &diff) != 0)
743 	    continue;
744 	if (es != NULL && diff < bestdiff) {
745 	    best = es;
746 	    bestdiff = diff;
747 	}
748 	if (bestdiff == 0)
749 	    break;
750     }
751     if (best) {
752 	*sym = best;
753 	*diffp = bestdiff;
754 	return 0;
755     } else {
756 	*sym = NULL;
757 	*diffp = off;
758 	return ENOENT;
759     }
760 }
761 
762 int
763 linker_ddb_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
764 {
765     linker_file_t lf;
766 
767     TAILQ_FOREACH(lf, &linker_files, link) {
768 	if (lf->ops->symbol_values(lf, sym, symval) == 0)
769 	    return 0;
770     }
771     return ENOENT;
772 }
773 
774 #endif
775 
776 /*
777  * Syscalls.
778  *
779  * MPALMOSTSAFE
780  */
781 int
782 sys_kldload(struct sysmsg *sysmsg, const struct kldload_args *uap)
783 {
784     struct thread *td = curthread;
785     char *file;
786     char *kldname, *modname;
787     linker_file_t lf;
788     int error = 0;
789 
790     sysmsg->sysmsg_result = -1;
791 
792     if (securelevel > 0 || kernel_mem_readonly)	/* redundant, but that's OK */
793 	return EPERM;
794 
795     if ((error = priv_check(td, PRIV_KLD_LOAD)) != 0)
796 	return error;
797 
798     file = kmalloc(MAXPATHLEN, M_TEMP, M_WAITOK);
799     if ((error = copyinstr(uap->file, file, MAXPATHLEN, NULL)) != 0)
800 	goto out;
801 
802     /*
803      * If file does not contain a qualified name or any dot in it
804      * (kldname.ko, or kldname.ver.ko) treat it as an interface
805      * name.
806      */
807     if (strchr(file, '/') || strchr(file, '.')) {
808 	kldname = file;
809 	modname = NULL;
810     } else {
811 	kldname = NULL;
812 	modname = file;
813     }
814 
815     lockmgr(&kld_lock, LK_EXCLUSIVE);
816     error = linker_load_module(kldname, modname, NULL, NULL, &lf);
817     lockmgr(&kld_lock, LK_RELEASE);
818     if (error)
819 	goto out;
820 
821     lf->userrefs++;
822     sysmsg->sysmsg_result = lf->id;
823 
824 out:
825     if (file)
826 	kfree(file, M_TEMP);
827     return error;
828 }
829 
830 /*
831  * MPALMOSTSAFE
832  */
833 int
834 sys_kldunload(struct sysmsg *sysmsg, const struct kldunload_args *uap)
835 {
836     struct thread *td = curthread;
837     linker_file_t lf;
838     int error = 0;
839 
840     if (securelevel > 0 || kernel_mem_readonly)	/* redundant, but that's OK */
841 	return EPERM;
842 
843     if ((error = priv_check(td, PRIV_KLD_UNLOAD)) != 0)
844 	return error;
845 
846     lockmgr(&kld_lock, LK_EXCLUSIVE);
847     lf = linker_find_file_by_id(uap->fileid);
848     if (lf) {
849 	KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
850 	if (lf->userrefs == 0) {
851 	    kprintf("linkerunload: attempt to unload file that was loaded by the kernel\n");
852 	    error = EBUSY;
853 	    goto out;
854 	}
855 	lf->userrefs--;
856 	error = linker_file_unload(lf);
857 	if (error)
858 	    lf->userrefs++;
859     } else {
860 	error = ENOENT;
861     }
862 out:
863     lockmgr(&kld_lock, LK_RELEASE);
864 
865     return error;
866 }
867 
868 /*
869  * MPALMOSTSAFE
870  */
871 int
872 sys_kldfind(struct sysmsg *sysmsg, const struct kldfind_args *uap)
873 {
874     char *pathname;
875     const char *filename;
876     linker_file_t lf;
877     int error;
878 
879     sysmsg->sysmsg_result = -1;
880 
881     pathname = kmalloc(MAXPATHLEN, M_TEMP, M_WAITOK);
882     if ((error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL)) != 0)
883 	goto out;
884 
885     filename = linker_basename(pathname);
886 
887     lockmgr(&kld_lock, LK_EXCLUSIVE);
888     lf = linker_find_file_by_name(filename);
889     if (lf)
890 	sysmsg->sysmsg_result = lf->id;
891     else
892 	error = ENOENT;
893     lockmgr(&kld_lock, LK_RELEASE);
894 
895 out:
896     if (pathname)
897 	kfree(pathname, M_TEMP);
898     return error;
899 }
900 
901 /*
902  * MPALMOSTSAFE
903  */
904 int
905 sys_kldnext(struct sysmsg *sysmsg, const struct kldnext_args *uap)
906 {
907     linker_file_t lf;
908     int error = 0;
909 
910     lockmgr(&kld_lock, LK_EXCLUSIVE);
911     if (uap->fileid == 0) {
912 	lf = TAILQ_FIRST(&linker_files);
913     } else {
914 	lf = linker_find_file_by_id(uap->fileid);
915 	if (lf == NULL) {
916 	    error = ENOENT;
917 	    goto out;
918 	}
919 	lf = TAILQ_NEXT(lf, link);
920     }
921 
922     /* Skip partially loaded files. */
923     while (lf != NULL && !(lf->flags & LINKER_FILE_LINKED)) {
924 	lf = TAILQ_NEXT(lf, link);
925     }
926 
927     if (lf)
928 	sysmsg->sysmsg_result = lf->id;
929     else
930 	sysmsg->sysmsg_result = 0;
931 
932 out:
933     lockmgr(&kld_lock, LK_RELEASE);
934 
935     return error;
936 }
937 
938 /*
939  * MPALMOSTSAFE
940  */
941 int
942 sys_kldstat(struct sysmsg *sysmsg, const struct kldstat_args *uap)
943 {
944     linker_file_t lf;
945     int error = 0;
946     int version;
947     struct kld_file_stat* stat;
948     int namelen;
949 
950     lockmgr(&kld_lock, LK_EXCLUSIVE);
951     lf = linker_find_file_by_id(uap->fileid);
952     if (!lf) {
953 	error = ENOENT;
954 	goto out;
955     }
956 
957     stat = uap->stat;
958 
959     /*
960      * Check the version of the user's structure.
961      */
962     if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
963 	goto out;
964     if (version != sizeof(struct kld_file_stat)) {
965 	error = EINVAL;
966 	goto out;
967     }
968 
969     namelen = strlen(lf->filename) + 1;
970     if (namelen > MAXPATHLEN)
971 	namelen = MAXPATHLEN;
972     if ((error = copyout(lf->filename, stat->name, namelen)) != 0)
973 	goto out;
974 
975     namelen = strlen(lf->pathname) + 1;
976     if (namelen > MAXPATHLEN)
977 	namelen = MAXPATHLEN;
978     if ((error = copyout(lf->pathname, stat->pathname, namelen)) != 0)
979 	goto out;
980 
981     if ((error = copyout(&lf->refs, &stat->refs, sizeof(int))) != 0)
982 	goto out;
983     if ((error = copyout(&lf->id, &stat->id, sizeof(int))) != 0)
984 	goto out;
985     if ((error = copyout(&lf->address, &stat->address, sizeof(caddr_t))) != 0)
986 	goto out;
987     if ((error = copyout(&lf->size, &stat->size, sizeof(size_t))) != 0)
988 	goto out;
989 
990     sysmsg->sysmsg_result = 0;
991 
992 out:
993     lockmgr(&kld_lock, LK_RELEASE);
994 
995     return error;
996 }
997 
998 /*
999  * MPALMOSTSAFE
1000  */
1001 int
1002 sys_kldfirstmod(struct sysmsg *sysmsg, const struct kldfirstmod_args *uap)
1003 {
1004     linker_file_t lf;
1005     int error = 0;
1006 
1007     lockmgr(&kld_lock, LK_EXCLUSIVE);
1008     lf = linker_find_file_by_id(uap->fileid);
1009     if (lf) {
1010 	if (TAILQ_FIRST(&lf->modules))
1011 	    sysmsg->sysmsg_result = module_getid(TAILQ_FIRST(&lf->modules));
1012 	else
1013 	    sysmsg->sysmsg_result = 0;
1014     } else {
1015 	error = ENOENT;
1016     }
1017     lockmgr(&kld_lock, LK_RELEASE);
1018 
1019     return error;
1020 }
1021 
1022 /*
1023  * MPALMOSTSAFE
1024  */
1025 int
1026 sys_kldsym(struct sysmsg *sysmsg, const struct kldsym_args *uap)
1027 {
1028     char *symstr = NULL;
1029     c_linker_sym_t sym;
1030     linker_symval_t symval;
1031     linker_file_t lf;
1032     struct kld_sym_lookup lookup;
1033     int error = 0;
1034 
1035     lockmgr(&kld_lock, LK_EXCLUSIVE);
1036     if ((error = copyin(uap->data, &lookup, sizeof(lookup))) != 0)
1037 	goto out;
1038     if (lookup.version != sizeof(lookup) || uap->cmd != KLDSYM_LOOKUP) {
1039 	error = EINVAL;
1040 	goto out;
1041     }
1042 
1043     symstr = kmalloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1044     if ((error = copyinstr(lookup.symname, symstr, MAXPATHLEN, NULL)) != 0)
1045 	goto out;
1046 
1047     if (uap->fileid != 0) {
1048 	lf = linker_find_file_by_id(uap->fileid);
1049 	if (lf == NULL) {
1050 	    error = ENOENT;
1051 	    goto out;
1052 	}
1053 	if (lf->ops->lookup_symbol(lf, symstr, &sym) == 0 &&
1054 	    lf->ops->symbol_values(lf, sym, &symval) == 0) {
1055 	    lookup.symvalue = (uintptr_t)symval.value;
1056 	    lookup.symsize = symval.size;
1057 	    error = copyout(&lookup, uap->data, sizeof(lookup));
1058 	} else
1059 	    error = ENOENT;
1060     } else {
1061 	TAILQ_FOREACH(lf, &linker_files, link) {
1062 	    if (lf->ops->lookup_symbol(lf, symstr, &sym) == 0 &&
1063 		lf->ops->symbol_values(lf, sym, &symval) == 0) {
1064 		lookup.symvalue = (uintptr_t)symval.value;
1065 		lookup.symsize = symval.size;
1066 		error = copyout(&lookup, uap->data, sizeof(lookup));
1067 		break;
1068 	    }
1069 	}
1070 	if (!lf)
1071 	    error = ENOENT;
1072     }
1073 out:
1074     lockmgr(&kld_lock, LK_RELEASE);
1075     if (symstr)
1076 	kfree(symstr, M_TEMP);
1077 
1078     return error;
1079 }
1080 
1081 /*
1082  * Preloaded module support
1083  */
1084 
1085 static modlist_t
1086 modlist_lookup(const char *name, int ver)
1087 {
1088     modlist_t	    mod;
1089 
1090     TAILQ_FOREACH(mod, &found_modules, link) {
1091 	if (strcmp(mod->name, name) == 0 && (ver == 0 || mod->version == ver))
1092 	    return (mod);
1093     }
1094     return (NULL);
1095 }
1096 
1097 static modlist_t
1098 modlist_lookup2(const char *name, struct mod_depend *verinfo)
1099 {
1100     modlist_t	    mod, bestmod;
1101     int		    ver;
1102 
1103     if (verinfo == NULL)
1104 	return (modlist_lookup(name, 0));
1105     bestmod = NULL;
1106     TAILQ_FOREACH(mod, &found_modules, link) {
1107 	if (strcmp(mod->name, name) != 0)
1108 	    continue;
1109 	ver = mod->version;
1110 	if (ver == verinfo->md_ver_preferred)
1111 	    return (mod);
1112 	if (ver >= verinfo->md_ver_minimum &&
1113 		ver <= verinfo->md_ver_maximum &&
1114 		(bestmod == NULL || ver > bestmod->version))
1115 	    bestmod = mod;
1116     }
1117     return (bestmod);
1118 }
1119 
1120 int
1121 linker_reference_module(const char *modname, struct mod_depend *verinfo,
1122     linker_file_t *result)
1123 {
1124     modlist_t mod;
1125     int error;
1126 
1127     lockmgr(&llf_lock, LK_SHARED);
1128     if ((mod = modlist_lookup2(modname, verinfo)) != NULL) {
1129         *result = mod->container;
1130         (*result)->refs++;
1131         lockmgr(&llf_lock, LK_RELEASE);
1132         return (0);
1133     }
1134 
1135     lockmgr(&llf_lock, LK_RELEASE);
1136     /*lockmgr(&kld_lock, LK_EXCLUSIVE);*/
1137     error = linker_load_module(NULL, modname, NULL, verinfo, result);
1138     /*lockmgr(&kld_lock, LK_RELEASE);*/
1139 
1140     return (error);
1141 }
1142 
1143 int
1144 linker_release_module(const char *modname, struct mod_depend *verinfo,
1145     linker_file_t lf)
1146 {
1147     modlist_t mod;
1148     int error;
1149 
1150     lockmgr(&llf_lock, LK_SHARED);
1151     if (lf == NULL) {
1152         KASSERT(modname != NULL,
1153             ("linker_release_module: no file or name"));
1154         mod = modlist_lookup2(modname, verinfo);
1155         if (mod == NULL) {
1156             lockmgr(&llf_lock, LK_RELEASE);
1157             return (ESRCH);
1158         }
1159         lf = mod->container;
1160     } else
1161         KASSERT(modname == NULL && verinfo == NULL,
1162             ("linker_release_module: both file and name"));
1163     lockmgr(&llf_lock, LK_RELEASE);
1164     /*lockmgr(&kld_lock, LK_EXCLUSIVE);*/
1165     error = linker_file_unload(lf);
1166     /*lockmgr(&kld_lock, LK_RELEASE);*/
1167 
1168     return (error);
1169 }
1170 
1171 static modlist_t
1172 modlist_newmodule(const char *modname, int version, linker_file_t container)
1173 {
1174     modlist_t	    mod;
1175 
1176     mod = kmalloc(sizeof(struct modlist), M_LINKER, M_NOWAIT | M_ZERO);
1177     if (mod == NULL)
1178 	panic("no memory for module list");
1179     mod->container = container;
1180     mod->name = modname;
1181     mod->version = version;
1182     TAILQ_INSERT_TAIL(&found_modules, mod, link);
1183     return (mod);
1184 }
1185 
1186 static void
1187 linker_addmodules(linker_file_t lf, struct mod_metadata **start,
1188 		  struct mod_metadata **stop, int preload)
1189 {
1190     struct mod_metadata *mp, **mdp;
1191     const char     *modname;
1192     int		    ver;
1193 
1194     for (mdp = start; mdp < stop; mdp++) {
1195 	mp = *mdp;
1196 	if (mp->md_type != MDT_VERSION)
1197 	    continue;
1198 	modname = mp->md_cval;
1199 	ver = ((struct mod_version *)mp->md_data)->mv_version;
1200 	if (modlist_lookup(modname, ver) != NULL) {
1201 	    kprintf("module %s already present!\n", modname);
1202 	    /* XXX what can we do? this is a build error. :-( */
1203 	    continue;
1204 	}
1205 	modlist_newmodule(modname, ver, lf);
1206     }
1207 }
1208 
1209 static void
1210 linker_preload(void* arg)
1211 {
1212     caddr_t		modptr;
1213     const char		*modname, *nmodname;
1214     char		*modtype;
1215     linker_file_t	lf, nlf;
1216     linker_class_t	lc;
1217     int			error;
1218     linker_file_list_t loaded_files;
1219     linker_file_list_t depended_files;
1220     struct mod_metadata *mp, *nmp;
1221     struct mod_metadata **start, **stop, **mdp, **nmdp;
1222     struct mod_depend *verinfo;
1223     int nver;
1224     int resolves;
1225     modlist_t mod;
1226     struct sysinit	**si_start, **si_stop;
1227 
1228     TAILQ_INIT(&loaded_files);
1229     TAILQ_INIT(&depended_files);
1230     TAILQ_INIT(&found_modules);
1231 
1232     modptr = NULL;
1233     while ((modptr = preload_search_next_name(modptr)) != NULL) {
1234 	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
1235 	modtype = (char *)preload_search_info(modptr, MODINFO_TYPE);
1236 	if (modname == NULL) {
1237 	    kprintf("Preloaded module at %p does not have a name!\n", modptr);
1238 	    continue;
1239 	}
1240 	if (modtype == NULL) {
1241 	    kprintf("Preloaded module at %p does not have a type!\n", modptr);
1242 	    continue;
1243 	}
1244 
1245 	if (bootverbose)
1246 	    kprintf("Preloaded %s \"%s\" at %p.\n", modtype, modname, modptr);
1247 	lf = NULL;
1248 	TAILQ_FOREACH(lc, &classes, link) {
1249 	    error = lc->ops->preload_file(modname, &lf);
1250 	    if (!error)
1251 		break;
1252 	    lf = NULL;
1253 	}
1254 	if (lf)
1255 		TAILQ_INSERT_TAIL(&loaded_files, lf, loaded);
1256     }
1257 
1258     /*
1259      * First get a list of stuff in the kernel.
1260      */
1261     if (linker_file_lookup_set(linker_kernel_file, MDT_SETNAME, &start,
1262 			       &stop, NULL) == 0)
1263 	linker_addmodules(linker_kernel_file, start, stop, 1);
1264 
1265     /*
1266      * This is a once-off kinky bubble sort to resolve relocation
1267      * dependency requirements.
1268      */
1269 restart:
1270     TAILQ_FOREACH(lf, &loaded_files, loaded) {
1271 	error = linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop, NULL);
1272 	/*
1273 	 * First, look to see if we would successfully link with this
1274 	 * stuff.
1275 	 */
1276 	resolves = 1;		/* unless we know otherwise */
1277 	if (!error) {
1278 	    for (mdp = start; mdp < stop; mdp++) {
1279 		mp = *mdp;
1280 		if (mp->md_type != MDT_DEPEND)
1281 		    continue;
1282 		modname = mp->md_cval;
1283 		verinfo = mp->md_data;
1284 		for (nmdp = start; nmdp < stop; nmdp++) {
1285 		    nmp = *nmdp;
1286 		    if (nmp->md_type != MDT_VERSION)
1287 			continue;
1288 		    nmodname = nmp->md_cval;
1289 		    if (strcmp(modname, nmodname) == 0)
1290 			break;
1291 		}
1292 		if (nmdp < stop)/* it's a self reference */
1293 		    continue;
1294 
1295 		/*
1296 		 * ok, the module isn't here yet, we
1297 		 * are not finished
1298 		 */
1299 		if (modlist_lookup2(modname, verinfo) == NULL)
1300 		    resolves = 0;
1301 	    }
1302 	}
1303 	/*
1304 	 * OK, if we found our modules, we can link.  So, "provide"
1305 	 * the modules inside and add it to the end of the link order
1306 	 * list.
1307 	 */
1308 	if (resolves) {
1309 	    if (!error) {
1310 		for (mdp = start; mdp < stop; mdp++) {
1311 		    mp = *mdp;
1312 		    if (mp->md_type != MDT_VERSION)
1313 			continue;
1314 		    modname = mp->md_cval;
1315 		    nver = ((struct mod_version *)mp->md_data)->mv_version;
1316 		    if (modlist_lookup(modname, nver) != NULL) {
1317 			kprintf("module %s already present!\n", modname);
1318 			TAILQ_REMOVE(&loaded_files, lf, loaded);
1319 			linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */ );
1320 			/* we changed tailq next ptr */
1321 			goto restart;
1322 		    }
1323 		    modlist_newmodule(modname, nver, lf);
1324 		}
1325 	    }
1326 	    TAILQ_REMOVE(&loaded_files, lf, loaded);
1327 	    TAILQ_INSERT_TAIL(&depended_files, lf, loaded);
1328 	    /*
1329 	     * Since we provided modules, we need to restart the
1330 	     * sort so that the previous files that depend on us
1331 	     * have a chance. Also, we've busted the tailq next
1332 	     * pointer with the REMOVE.
1333 	     */
1334 	    goto restart;
1335 	}
1336     }
1337 
1338     /*
1339      * At this point, we check to see what could not be resolved..
1340      */
1341     while ((lf = TAILQ_FIRST(&loaded_files)) != NULL) {
1342 	TAILQ_REMOVE(&loaded_files, lf, loaded);
1343 	kprintf("KLD file %s is missing dependencies\n", lf->filename);
1344 	linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */ );
1345     }
1346 
1347     /*
1348      * We made it. Finish off the linking in the order we determined.
1349      */
1350     TAILQ_FOREACH_MUTABLE(lf, &depended_files, loaded, nlf) {
1351 	if (linker_kernel_file) {
1352 	    linker_kernel_file->refs++;
1353 	    linker_file_add_dependancy(lf, linker_kernel_file);
1354 	}
1355 	lf->userrefs++;
1356 
1357 	error = linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop, NULL);
1358 	if (!error) {
1359 	    for (mdp = start; mdp < stop; mdp++) {
1360 		mp = *mdp;
1361 		if (mp->md_type != MDT_DEPEND)
1362 		    continue;
1363 		modname = mp->md_cval;
1364 		verinfo = mp->md_data;
1365 		mod = modlist_lookup2(modname, verinfo);
1366 		/* Don't count self-dependencies */
1367 		if (lf == mod->container)
1368 		    continue;
1369 		mod->container->refs++;
1370 		linker_file_add_dependancy(lf, mod->container);
1371 	    }
1372 	}
1373 	/*
1374 	 * Now do relocation etc using the symbol search paths
1375 	 * established by the dependencies
1376 	 */
1377 	error = lf->ops->preload_finish(lf);
1378 	if (error) {
1379 	    TAILQ_REMOVE(&depended_files, lf, loaded);
1380 	    kprintf("KLD file %s - could not finalize loading\n",
1381 		    lf->filename);
1382 	    linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */);
1383 	    continue;
1384 	}
1385 	linker_file_register_modules(lf);
1386 	if (linker_file_lookup_set(lf, "sysinit_set", &si_start, &si_stop, NULL) == 0)
1387 	    sysinit_add(si_start, si_stop);
1388 	linker_file_register_sysctls(lf);
1389 	lf->flags |= LINKER_FILE_LINKED;
1390     }
1391     /* woohoo! we made it! */
1392 }
1393 
1394 SYSINIT(preload, SI_BOOT2_KLD, SI_ORDER_MIDDLE, linker_preload, 0);
1395 
1396 /*
1397  * Search for a not-loaded module by name.
1398  *
1399  * Modules may be found in the following locations:
1400  *
1401  * - preloaded (result is just the module name)
1402  * - on disk (result is full path to module)
1403  *
1404  * The search path can be manipulated via sysctl.  Note that we use the ';'
1405  * character as a separator to be consistent with the bootloader.
1406  */
1407 
1408 static char linker_path[MAXPATHLEN] = "/boot/kernel;/boot/modules.local";
1409 
1410 SYSCTL_STRING(_kern, OID_AUTO, module_path, CTLFLAG_RW, linker_path,
1411 	      sizeof(linker_path), "module load search path");
1412 TUNABLE_STR("module_path", linker_path, sizeof(linker_path));
1413 
1414 char *
1415 linker_search_path(const char *name)
1416 {
1417     struct nlookupdata	nd;
1418     char		*cp, *ep, *result;
1419     char		*buf, *retbuf, *freebuf;
1420     size_t		name_len, prefix_len;
1421     size_t		result_len;
1422     int			sep;
1423     int			error;
1424     enum vtype		type;
1425     const char *exts[] = { "", ".ko", NULL };
1426     const char **ext;
1427 
1428     /* already full path */
1429     if (name[0] == '/')
1430 	return linker_strdup(name);
1431 
1432     /* resolve to full path */
1433     if (strchr(name, '/') != NULL) {
1434 	result = NULL;
1435 
1436 	/* adapted from sys___realpath() */
1437 	error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_FOLLOW);
1438 	if (error == 0) {
1439 	    nd.nl_flags |= NLC_SHAREDLOCK;
1440 	    error = nlookup(&nd);
1441 	}
1442 	if (error == 0) {
1443 	    if (nd.nl_flags & NLC_NCPISLOCKED) {
1444 		nd.nl_flags &= ~NLC_NCPISLOCKED;
1445 		cache_unlock(&nd.nl_nch);
1446 	    }
1447 	    error = cache_fullpath(curproc, &nd.nl_nch, NULL,
1448 				   &retbuf, &freebuf, 0);
1449 	    if (error == 0) {
1450 		result = linker_strdup(retbuf);
1451 		kfree(freebuf, M_TEMP);
1452 	    }
1453 	}
1454 	nlookup_done(&nd);
1455 
1456 	return (result);
1457     }
1458 
1459     /* traverse the linker path */
1460     buf = kmalloc(MAXPATHLEN, M_LINKER, M_WAITOK);
1461     cp = linker_path;
1462     name_len = strlen(name);
1463     for (;;) {
1464 	/* find the end of this component */
1465 	for (ep = cp; (*ep != 0) && (*ep != ';'); ep++)
1466 	    ;
1467 	prefix_len = ep - cp;
1468 	/* if this component doesn't end with a slash, add one */
1469 	if (ep == cp || *(ep - 1) != '/')
1470 	    sep = 1;
1471 	else
1472 	    sep = 0;
1473 
1474 	result = buf;
1475 	strncpy(result, cp, prefix_len);
1476 	if (sep)
1477 	    result[prefix_len++] = '/';
1478 	strcpy(result + prefix_len, name);
1479 
1480 	result_len = strlen(result);
1481 	for (ext = exts; *ext != NULL; ext++) {
1482 	    strcpy(result + result_len, *ext);
1483 
1484 	    /*
1485 	     * Attempt to open the file, and return the path if we succeed and it's
1486 	     * a regular file.
1487 	     */
1488 	    error = nlookup_init(&nd, result, UIO_SYSSPACE, NLC_FOLLOW|NLC_LOCKVP);
1489 	    if (error == 0)
1490 		error = vn_open(&nd, NULL, FREAD, 0);
1491 	    if (error == 0) {
1492 		type = nd.nl_open_vp->v_type;
1493 		if (type == VREG) {
1494 		    nlookup_done(&nd);
1495 		    return (result);
1496 		}
1497 	    }
1498 	    nlookup_done(&nd);
1499 	}
1500 
1501 	if (*ep == 0)
1502 	    break;
1503 	cp = ep + 1;
1504     }
1505 
1506     kfree(buf, M_LINKER);
1507     return(NULL);
1508 }
1509 
1510 /*
1511  * Find a file which contains given module and load it, if "parent" is not
1512  * NULL, register a reference to it.
1513  */
1514 static int
1515 linker_load_module(const char *kldname, const char *modname,
1516 		   struct linker_file *parent, struct mod_depend *verinfo,
1517 		   struct linker_file **lfpp)
1518 {
1519     linker_file_t   lfdep;
1520     const char     *filename;
1521     char           *pathname;
1522     int		    error;
1523 
1524     if (modname == NULL) {
1525 	/*
1526 	 * We have to load KLD
1527 	 */
1528 	KASSERT(verinfo == NULL, ("linker_load_module: verinfo is not NULL"));
1529 	pathname = linker_search_path(kldname);
1530     } else {
1531 	if (modlist_lookup2(modname, verinfo) != NULL)
1532 	    return (EEXIST);
1533 	if (kldname != NULL) {
1534 	    pathname = linker_strdup(kldname);
1535 	} else if (rootvnode == NULL) {
1536 	    pathname = NULL;
1537 	} else {
1538 	    pathname = linker_search_path(modname);
1539 	}
1540 #if 0
1541 	/*
1542 	 * Need to find a KLD with required module
1543 	 */
1544 	pathname = linker_search_module(modname,
1545 					strlen(modname), verinfo);
1546 #endif
1547     }
1548     if (pathname == NULL)
1549 	return (ENOENT);
1550 
1551     /*
1552      * Can't load more than one file with the same basename XXX:
1553      * Actually it should be possible to have multiple KLDs with
1554      * the same basename but different path because they can
1555      * provide different versions of the same modules.
1556      */
1557     filename = linker_basename(pathname);
1558     if (linker_find_file_by_name(filename))
1559 	error = EEXIST;
1560     else
1561 	do {
1562 	    error = linker_load_file(pathname, &lfdep);
1563 	    if (error)
1564 		break;
1565 	    if (modname && verinfo && modlist_lookup2(modname, verinfo) == NULL) {
1566 		linker_file_unload(lfdep /* , LINKER_UNLOAD_FORCE */ );
1567 		error = ENOENT;
1568 		break;
1569 	    }
1570 	    if (parent) {
1571 		linker_file_add_dependancy(parent, lfdep);
1572 	    }
1573 	    if (lfpp)
1574 		*lfpp = lfdep;
1575 	} while (0);
1576     kfree(pathname, M_LINKER);
1577     return (error);
1578 }
1579 
1580 /*
1581  * This routine is responsible for finding dependencies of userland initiated
1582  * kldload(2)'s of files.
1583  */
1584 int
1585 linker_load_dependencies(linker_file_t lf)
1586 {
1587     linker_file_t   lfdep;
1588     struct mod_metadata **start, **stop, **mdp, **nmdp;
1589     struct mod_metadata *mp, *nmp;
1590     struct mod_depend *verinfo;
1591     modlist_t	    mod;
1592     const char     *modname, *nmodname;
1593     int		    ver, error = 0, count;
1594 
1595     /*
1596      * All files are dependant on /kernel.
1597      */
1598     if (linker_kernel_file) {
1599 	linker_kernel_file->refs++;
1600 	linker_file_add_dependancy(lf, linker_kernel_file);
1601     }
1602     if (linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop, &count) != 0)
1603 	return (0);
1604     for (mdp = start; mdp < stop; mdp++) {
1605 	mp = *mdp;
1606 	if (mp->md_type != MDT_VERSION)
1607 	    continue;
1608 	modname = mp->md_cval;
1609 	ver = ((struct mod_version *)mp->md_data)->mv_version;
1610 	mod = modlist_lookup(modname, ver);
1611 	if (mod != NULL) {
1612 	    kprintf("interface %s.%d already present in the KLD '%s'!\n",
1613 		    modname, ver, mod->container->filename);
1614 	    return (EEXIST);
1615 	}
1616     }
1617 
1618     for (mdp = start; mdp < stop; mdp++) {
1619 	mp = *mdp;
1620 	if (mp->md_type != MDT_DEPEND)
1621 	    continue;
1622 	modname = mp->md_cval;
1623 	verinfo = mp->md_data;
1624 	nmodname = NULL;
1625 	for (nmdp = start; nmdp < stop; nmdp++) {
1626 	    nmp = *nmdp;
1627 	    if (nmp->md_type != MDT_VERSION)
1628 		continue;
1629 	    nmodname = nmp->md_cval;
1630 	    if (strcmp(modname, nmodname) == 0)
1631 		break;
1632 	}
1633 	if (nmdp < stop)	/* early exit, it's a self reference */
1634 	    continue;
1635 	mod = modlist_lookup2(modname, verinfo);
1636 	if (mod) {		/* woohoo, it's loaded already */
1637 	    lfdep = mod->container;
1638 	    lfdep->refs++;
1639 	    linker_file_add_dependancy(lf, lfdep);
1640 	    continue;
1641 	}
1642 	error = linker_load_module(NULL, modname, lf, verinfo, NULL);
1643 	if (error) {
1644 	    kprintf("KLD %s: depends on %s - not available or version mismatch\n",
1645 		    lf->filename, modname);
1646 	    break;
1647 	}
1648     }
1649 
1650     if (error)
1651 	return (error);
1652     linker_addmodules(lf, start, stop, 0);
1653     return (0);
1654 }
1655