xref: /dragonfly/sys/kern/kern_linker.c (revision 8d1e479a)
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 void
99 linker_init(void* arg)
100 {
101     lockinit(&llf_lock, "klink", 0, 0);
102     lockinit(&kld_lock, "kldlk", 0, LK_CANRECURSE);
103     TAILQ_INIT(&classes);
104     TAILQ_INIT(&linker_files);
105 }
106 
107 SYSINIT(linker, SI_BOOT2_KLD, SI_ORDER_FIRST, linker_init, 0);
108 
109 int
110 linker_add_class(const char* desc, void* priv,
111 		 struct linker_class_ops* ops)
112 {
113     linker_class_t lc;
114 
115     lc = kmalloc(sizeof(struct linker_class), M_LINKER, M_NOWAIT | M_ZERO);
116     if (!lc)
117 	return ENOMEM;
118 
119     lc->desc = desc;
120     lc->priv = priv;
121     lc->ops = ops;
122     TAILQ_INSERT_HEAD(&classes, lc, link);
123 
124     return 0;
125 }
126 
127 static void
128 linker_file_sysinit(linker_file_t lf)
129 {
130     struct sysinit** start, ** stop;
131     struct sysinit** sipp;
132     struct sysinit** xipp;
133     struct sysinit* save;
134 
135     KLD_DPF(FILE, ("linker_file_sysinit: calling SYSINITs for %s\n",
136 		   lf->filename));
137 
138     if (linker_file_lookup_set(lf, "sysinit_set", &start, &stop, NULL) != 0)
139 	return;
140 
141     /*
142      * Perform a bubble sort of the system initialization objects by
143      * their subsystem (primary key) and order (secondary key).
144      *
145      * Since some things care about execution order, this is the
146      * operation which ensures continued function.
147      */
148     for (sipp = start; sipp < stop; sipp++) {
149 	for (xipp = sipp + 1; xipp < stop; xipp++) {
150 	    if ((*sipp)->subsystem < (*xipp)->subsystem ||
151 		 ((*sipp)->subsystem == (*xipp)->subsystem &&
152 		  (*sipp)->order <= (*xipp)->order))
153 		continue;	/* skip*/
154 	    save = *sipp;
155 	    *sipp = *xipp;
156 	    *xipp = save;
157 	}
158     }
159 
160 
161     /*
162      * Traverse the (now) ordered list of system initialization tasks.
163      * Perform each task, and continue on to the next task.
164      */
165     for (sipp = start; sipp < stop; sipp++) {
166 	if ((*sipp)->subsystem == SI_SPECIAL_DUMMY)
167 	    continue;	/* skip dummy task(s)*/
168 
169 	/* Call function */
170 	(*((*sipp)->func))((*sipp)->udata);
171     }
172 }
173 
174 static void
175 linker_file_sysuninit(linker_file_t lf)
176 {
177     struct sysinit** start, ** stop;
178     struct sysinit** sipp;
179     struct sysinit** xipp;
180     struct sysinit* save;
181 
182     KLD_DPF(FILE, ("linker_file_sysuninit: calling SYSUNINITs for %s\n",
183 		   lf->filename));
184 
185     if (linker_file_lookup_set(lf, "sysuninit_set", &start, &stop, NULL) != 0)
186 	return;
187 
188     /*
189      * Perform a reverse bubble sort of the system initialization objects
190      * by their subsystem (primary key) and order (secondary key).
191      *
192      * Since some things care about execution order, this is the
193      * operation which ensures continued function.
194      */
195     for (sipp = start; sipp < stop; sipp++) {
196 	for (xipp = sipp + 1; xipp < stop; xipp++) {
197 	    if ((*sipp)->subsystem > (*xipp)->subsystem ||
198 		 ((*sipp)->subsystem == (*xipp)->subsystem &&
199 		  (*sipp)->order >= (*xipp)->order))
200 		continue;	/* skip*/
201 	    save = *sipp;
202 	    *sipp = *xipp;
203 	    *xipp = save;
204 	}
205     }
206 
207 
208     /*
209      * Traverse the (now) ordered list of system initialization tasks.
210      * Perform each task, and continue on to the next task.
211      */
212     for (sipp = start; sipp < stop; sipp++) {
213 	if ((*sipp)->subsystem == SI_SPECIAL_DUMMY)
214 	    continue;	/* skip dummy task(s)*/
215 
216 	/* Call function */
217 	(*((*sipp)->func))((*sipp)->udata);
218     }
219 }
220 
221 static void
222 linker_file_register_sysctls(linker_file_t lf)
223 {
224     struct sysctl_oid **start, **stop, **oidp;
225 
226     KLD_DPF(FILE, ("linker_file_register_sysctls: registering SYSCTLs for %s\n",
227 		   lf->filename));
228 
229     if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
230 	return;
231     for (oidp = start; oidp < stop; oidp++)
232 	sysctl_register_oid(*oidp);
233 }
234 
235 static void
236 linker_file_unregister_sysctls(linker_file_t lf)
237 {
238     struct sysctl_oid **start, **stop, **oidp;
239 
240     KLD_DPF(FILE, ("linker_file_unregister_sysctls: registering SYSCTLs for %s\n",
241 		   lf->filename));
242 
243     if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
244 	return;
245     for (oidp = start; oidp < stop; oidp++)
246 	sysctl_unregister_oid(*oidp);
247 }
248 
249 static int
250 linker_file_register_modules(linker_file_t lf)
251 {
252     struct mod_metadata **start, **stop, **mdp;
253     const moduledata_t *moddata;
254     int		    first_error, error;
255 
256     KLD_DPF(FILE, ("linker_file_register_modules: registering modules in %s\n",
257 		   lf->filename));
258 
259     if (linker_file_lookup_set(lf, "modmetadata_set", &start, &stop, NULL) != 0) {
260 	/*
261 	 * This fallback should be unnecessary, but if we get booted
262 	 * from boot2 instead of loader and we are missing our
263 	 * metadata then we have to try the best we can.
264 	 */
265 	if (lf == linker_kernel_file) {
266 	    start = SET_BEGIN(modmetadata_set);
267 	    stop = SET_LIMIT(modmetadata_set);
268 	} else
269 	    return (0);
270     }
271     first_error = 0;
272     for (mdp = start; mdp < stop; mdp++) {
273 	if ((*mdp)->md_type != MDT_MODULE)
274 	    continue;
275 	moddata = (*mdp)->md_data;
276 	KLD_DPF(FILE, ("Registering module %s in %s\n", moddata->name, lf->filename));
277 	error = module_register(moddata, lf);
278 	if (error) {
279 	    kprintf("Module %s failed to register: %d\n", moddata->name, error);
280 	    if (first_error == 0)
281 		first_error = error;
282 	}
283     }
284     return (first_error);
285 }
286 
287 static void
288 linker_init_kernel_modules(void)
289 {
290 
291     linker_file_register_modules(linker_kernel_file);
292 }
293 
294 SYSINIT(linker_kernel, SI_BOOT2_KLD, SI_ORDER_ANY, linker_init_kernel_modules, 0);
295 
296 int
297 linker_load_file(const char *filename, linker_file_t *result)
298 {
299     linker_class_t lc;
300     linker_file_t lf;
301     int foundfile, error = 0;
302 
303     /* Refuse to load modules if securelevel raised */
304     if (securelevel > 0 || kernel_mem_readonly)
305 	return EPERM;
306 
307     lf = linker_find_file_by_name(filename);
308     if (lf) {
309 	KLD_DPF(FILE, ("linker_load_file: file %s is already loaded, incrementing refs\n", filename));
310 	*result = lf;
311 	lf->refs++;
312 	goto out;
313     }
314 
315     lf = NULL;
316     foundfile = 0;
317     TAILQ_FOREACH(lc, &classes, link) {
318 	KLD_DPF(FILE, ("linker_load_file: trying to load %s as %s\n",
319 		       filename, lc->desc));
320 
321 	error = lc->ops->load_file(filename, &lf);
322 	/*
323 	 * If we got something other than ENOENT, then it exists but we cannot
324 	 * load it for some other reason.
325 	 */
326 	if (error != ENOENT)
327 	    foundfile = 1;
328 	if (lf) {
329 	    error = linker_file_register_modules(lf);
330 	    if (error == EEXIST) {
331 		    linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */);
332 		    return (error);
333 	    }
334 	    linker_file_register_sysctls(lf);
335 	    linker_file_sysinit(lf);
336 	    lf->flags |= LINKER_FILE_LINKED;
337 	    *result = lf;
338 	    return (0);
339 	}
340     }
341     /*
342      * Less than ideal, but tells the user whether it failed to load or
343      * the module was not found.
344      */
345     if (foundfile) {
346 	    /*
347 	     * If the file type has not been recognized by the last try
348 	     * printout a message before to fail.
349 	     */
350 	    if (error == ENOSYS)
351 		    kprintf("linker_load_file: Unsupported file type\n");
352 
353 	    /*
354 	     * Format not recognized or otherwise unloadable.
355 	     * When loading a module that is statically built into
356 	     * the kernel EEXIST percolates back up as the return
357 	     * value.  Preserve this so that apps can recognize this
358 	     * special case.
359 	     */
360 	    if (error != EEXIST)
361 		    error = ENOEXEC;
362     } else {
363 	error = ENOENT;		/* Nothing found */
364     }
365 
366 out:
367     return error;
368 }
369 
370 
371 linker_file_t
372 linker_find_file_by_name(const char* filename)
373 {
374     linker_file_t lf = NULL;
375     char *koname;
376     int i;
377 
378     for (i = strlen(filename); i > 0 && filename[i-1] != '/'; --i)
379 	;
380     filename += i;
381 
382     koname = kmalloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
383     ksprintf(koname, "%s.ko", filename);
384 
385     lockmgr(&llf_lock, LK_SHARED);
386     TAILQ_FOREACH(lf, &linker_files, link) {
387 	if (!strcmp(lf->filename, koname))
388 	    break;
389 	if (!strcmp(lf->filename, filename))
390 	    break;
391     }
392     lockmgr(&llf_lock, LK_RELEASE);
393 
394     if (koname)
395 	kfree(koname, M_LINKER);
396     return lf;
397 }
398 
399 linker_file_t
400 linker_find_file_by_id(int fileid)
401 {
402     linker_file_t lf = NULL;
403 
404     lockmgr(&llf_lock, LK_SHARED);
405     TAILQ_FOREACH(lf, &linker_files, link) {
406 	if (lf->id == fileid)
407 	    break;
408     }
409     lockmgr(&llf_lock, LK_RELEASE);
410 
411     return lf;
412 }
413 
414 int
415 linker_file_foreach(linker_predicate_t *predicate, void *context)
416 {
417     linker_file_t lf;
418     int retval = 0;
419 
420     lockmgr(&llf_lock, LK_SHARED);
421     TAILQ_FOREACH(lf, &linker_files, link) {
422 	retval = predicate(lf, context);
423 	if (retval != 0)
424 	    break;
425     }
426     lockmgr(&llf_lock, LK_RELEASE);
427 
428     return (retval);
429 }
430 
431 linker_file_t
432 linker_make_file(const char* pathname, void* priv, struct linker_file_ops* ops)
433 {
434     linker_file_t lf = NULL;
435     const char *filename;
436 
437     filename = rindex(pathname, '/');
438     if (filename && filename[1])
439 	filename++;
440     else
441 	filename = pathname;
442 
443     KLD_DPF(FILE, ("linker_make_file: new file, filename=%s, pathname=%s\n",
444 		   filename, pathname));
445     lockmgr(&llf_lock, LK_EXCLUSIVE);
446     lf = kmalloc(sizeof(struct linker_file), M_LINKER, M_WAITOK | M_ZERO);
447     lf->refs = 1;
448     lf->userrefs = 0;
449     lf->flags = 0;
450     lf->filename = linker_strdup(filename);
451     lf->pathname = linker_strdup(pathname);
452     lf->id = next_file_id++;
453     lf->ndeps = 0;
454     lf->deps = NULL;
455     STAILQ_INIT(&lf->common);
456     TAILQ_INIT(&lf->modules);
457 
458     lf->priv = priv;
459     lf->ops = ops;
460     TAILQ_INSERT_TAIL(&linker_files, lf, link);
461 
462     lockmgr(&llf_lock, LK_RELEASE);
463 
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 = 0;
474     int i;
475 
476     /* Refuse to unload modules if securelevel raised */
477     if (securelevel > 0 || kernel_mem_readonly)
478 	return EPERM;
479 
480     KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
481 
482     lockmgr(&llf_lock, LK_EXCLUSIVE);
483 
484     /* Easy case of just dropping a reference. */
485     if (file->refs > 1) {
486 	    file->refs--;
487 	    lockmgr(&llf_lock, LK_RELEASE);
488 	    return (0);
489     }
490 
491     KLD_DPF(FILE, ("linker_file_unload: file is unloading, informing modules\n"));
492 
493     /*
494      * Inform any modules associated with this file.
495      */
496     mod = TAILQ_FIRST(&file->modules);
497     for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
498 	next = module_getfnext(mod);
499 
500 	/*
501 	 * Give the module a chance to veto the unload.  Note that the
502 	 * act of unloading the module may cause other modules in the
503 	 * same file list to be unloaded recursively.
504 	 */
505 	if ((error = module_unload(mod)) != 0) {
506 	    KLD_DPF(FILE, ("linker_file_unload: module %p vetoes unload\n",
507 			   mod));
508 	    lockmgr(&llf_lock, LK_RELEASE);
509 	    file->refs--;
510 	    goto out;
511 	}
512 	module_release(mod);
513     }
514 
515     TAILQ_FOREACH_MUTABLE(ml, &found_modules, link, nextml) {
516 	if (ml->container == file) {
517 	    TAILQ_REMOVE(&found_modules, ml, link);
518 	    kfree(ml, M_LINKER);
519 	}
520     }
521 
522     /* Don't try to run SYSUNINITs if we are unloaded due to a link error */
523     if (file->flags & LINKER_FILE_LINKED) {
524 	file->flags &= ~LINKER_FILE_LINKED;
525 	lockmgr(&llf_lock, LK_RELEASE);
526 	linker_file_sysuninit(file);
527 	linker_file_unregister_sysctls(file);
528 	lockmgr(&llf_lock, LK_EXCLUSIVE);
529     }
530 
531     TAILQ_REMOVE(&linker_files, file, link);
532 
533     if (file->deps) {
534 	lockmgr(&llf_lock, LK_RELEASE);
535 	for (i = 0; i < file->ndeps; i++)
536 	    linker_file_unload(file->deps[i]);
537 	lockmgr(&llf_lock, LK_EXCLUSIVE);
538 	kfree(file->deps, M_LINKER);
539 	file->deps = NULL;
540     }
541 
542     while ((cp = STAILQ_FIRST(&file->common)) != NULL) {
543 	STAILQ_REMOVE_HEAD(&file->common, link);
544 	kfree(cp, M_LINKER);
545     }
546 
547     file->ops->unload(file);
548 
549     if (file->filename) {
550 	kfree(file->filename, M_LINKER);
551 	file->filename = NULL;
552     }
553     if (file->pathname) {
554 	kfree(file->pathname, M_LINKER);
555 	file->pathname = NULL;
556     }
557 
558     kfree(file, M_LINKER);
559 
560     lockmgr(&llf_lock, LK_RELEASE);
561 
562 out:
563     return error;
564 }
565 
566 void
567 linker_file_add_dependancy(linker_file_t file, linker_file_t dep)
568 {
569     linker_file_t* newdeps;
570 
571     newdeps = kmalloc((file->ndeps + 1) * sizeof(linker_file_t*),
572 		     M_LINKER, M_WAITOK | M_ZERO);
573 
574     if (file->deps) {
575 	bcopy(file->deps, newdeps, file->ndeps * sizeof(linker_file_t*));
576 	kfree(file->deps, M_LINKER);
577     }
578     file->deps = newdeps;
579     file->deps[file->ndeps] = dep;
580     file->ndeps++;
581 }
582 
583 /*
584  * Locate a linker set and its contents.
585  * This is a helper function to avoid linker_if.h exposure elsewhere.
586  * Note: firstp and lastp are really void ***
587  */
588 int
589 linker_file_lookup_set(linker_file_t file, const char *name,
590                       void *firstp, void *lastp, int *countp)
591 {
592     return file->ops->lookup_set(file, name, firstp, lastp, countp);
593 }
594 
595 int
596 linker_file_lookup_symbol(linker_file_t file, const char* name, int deps, caddr_t *raddr)
597 {
598     c_linker_sym_t sym;
599     linker_symval_t symval;
600     linker_file_t lf;
601     size_t common_size = 0;
602     int i;
603 
604     KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n",
605 		  file, name, deps));
606 
607     if (file->ops->lookup_symbol(file, name, &sym) == 0) {
608 	file->ops->symbol_values(file, sym, &symval);
609 
610 	/*
611 	 * XXX Assume a common symbol if its value is 0 and it has a non-zero
612 	 * size, otherwise it could be an absolute symbol with a value of 0.
613 	 */
614 	if (symval.value == NULL && symval.size != 0) {
615 	    /*
616 	     * For commons, first look them up in the dependancies and
617 	     * only allocate space if not found there.
618 	     */
619 	    common_size = symval.size;
620 	} else {
621 	    KLD_DPF(SYM, ("linker_file_lookup_symbol: symbol.value=%p\n", symval.value));
622 	    *raddr = symval.value;
623 	    return 0;
624 	}
625     }
626     if (deps) {
627 	for (i = 0; i < file->ndeps; i++) {
628 	    if (linker_file_lookup_symbol(file->deps[i], name, 0, raddr) == 0) {
629 		KLD_DPF(SYM, ("linker_file_lookup_symbol: deps value=%p\n", *raddr));
630 		return 0;
631 	    }
632 	}
633 
634 	/* If we have not found it in the dependencies, search globally */
635 	TAILQ_FOREACH(lf, &linker_files, link) {
636 	    /* But skip the current file if it's on the list */
637 	    if (lf == file)
638 		continue;
639 	    /* And skip the files we searched above */
640 	    for (i = 0; i < file->ndeps; i++)
641 		if (lf == file->deps[i])
642 		    break;
643 	    if (i < file->ndeps)
644 		continue;
645 	    if (linker_file_lookup_symbol(lf, name, 0, raddr) == 0) {
646 		KLD_DPF(SYM, ("linker_file_lookup_symbol: global value=%p\n", *raddr));
647 		return 0;
648 	    }
649 	}
650     }
651 
652     if (common_size > 0) {
653 	/*
654 	 * This is a common symbol which was not found in the
655 	 * dependancies.  We maintain a simple common symbol table in
656 	 * the file object.
657 	 */
658 	struct common_symbol* cp;
659 
660 	STAILQ_FOREACH(cp, &file->common, link)
661 	    if (!strcmp(cp->name, name)) {
662 		KLD_DPF(SYM, ("linker_file_lookup_symbol: old common value=%p\n", cp->address));
663 		*raddr = cp->address;
664 		return 0;
665 	    }
666 
667 	/*
668 	 * Round the symbol size up to align.
669 	 */
670 	common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
671 	cp = kmalloc(sizeof(struct common_symbol)
672 		    + common_size
673 		    + strlen(name) + 1,
674 		    M_LINKER, M_WAITOK | M_ZERO);
675 
676 	cp->address = (caddr_t) (cp + 1);
677 	cp->name = cp->address + common_size;
678 	strcpy(cp->name, name);
679 	bzero(cp->address, common_size);
680 	STAILQ_INSERT_TAIL(&file->common, cp, link);
681 
682 	KLD_DPF(SYM, ("linker_file_lookup_symbol: new common value=%p\n", cp->address));
683 	*raddr = cp->address;
684 	return 0;
685     }
686 
687 #ifdef _KERNEL_VIRTUAL
688     *raddr = dlsym(RTLD_NEXT, name);
689     if (*raddr != NULL) {
690 	KLD_DPF(SYM, ("linker_file_lookup_symbol: found dlsym=%p\n", *raddr));
691 	return 0;
692     }
693 #endif
694 
695     KLD_DPF(SYM, ("linker_file_lookup_symbol: fail\n"));
696     return ENOENT;
697 }
698 
699 #ifdef DDB
700 /*
701  * DDB Helpers.  DDB has to look across multiple files with their own
702  * symbol tables and string tables.
703  *
704  * Note that we do not obey list locking protocols here.  We really don't
705  * need DDB to hang because somebody's got the lock held.  We'll take the
706  * chance that the files list is inconsistant instead.
707  */
708 
709 int
710 linker_ddb_lookup(const char *symstr, c_linker_sym_t *sym)
711 {
712     linker_file_t lf;
713 
714     TAILQ_FOREACH(lf, &linker_files, link) {
715 	if (lf->ops->lookup_symbol(lf, symstr, sym) == 0)
716 	    return 0;
717     }
718     return ENOENT;
719 }
720 
721 int
722 linker_ddb_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
723 {
724     linker_file_t lf;
725     u_long off = (uintptr_t)value;
726     u_long diff, bestdiff;
727     c_linker_sym_t best;
728     c_linker_sym_t es;
729 
730     best = NULL;
731     bestdiff = off;
732     TAILQ_FOREACH(lf, &linker_files, link) {
733 	if (lf->ops->search_symbol(lf, value, &es, &diff) != 0)
734 	    continue;
735 	if (es != NULL && diff < bestdiff) {
736 	    best = es;
737 	    bestdiff = diff;
738 	}
739 	if (bestdiff == 0)
740 	    break;
741     }
742     if (best) {
743 	*sym = best;
744 	*diffp = bestdiff;
745 	return 0;
746     } else {
747 	*sym = NULL;
748 	*diffp = off;
749 	return ENOENT;
750     }
751 }
752 
753 int
754 linker_ddb_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
755 {
756     linker_file_t lf;
757 
758     TAILQ_FOREACH(lf, &linker_files, link) {
759 	if (lf->ops->symbol_values(lf, sym, symval) == 0)
760 	    return 0;
761     }
762     return ENOENT;
763 }
764 
765 #endif
766 
767 /*
768  * Syscalls.
769  *
770  * MPALMOSTSAFE
771  */
772 int
773 sys_kldload(struct sysmsg *sysmsg, const struct kldload_args *uap)
774 {
775     struct thread *td = curthread;
776     char *file;
777     char *kldname, *modname;
778     linker_file_t lf;
779     int error = 0;
780 
781     sysmsg->sysmsg_result = -1;
782 
783     if (securelevel > 0 || kernel_mem_readonly)	/* redundant, but that's OK */
784 	return EPERM;
785 
786     if ((error = priv_check(td, PRIV_KLD_LOAD)) != 0)
787 	return error;
788 
789     file = kmalloc(MAXPATHLEN, M_TEMP, M_WAITOK);
790     if ((error = copyinstr(uap->file, file, MAXPATHLEN, NULL)) != 0)
791 	goto out;
792 
793     /*
794      * If file does not contain a qualified name or any dot in it
795      * (kldname.ko, or kldname.ver.ko) treat it as an interface
796      * name.
797      */
798     if (index(file, '/') || index(file, '.')) {
799 	kldname = file;
800 	modname = NULL;
801     } else {
802 	kldname = NULL;
803 	modname = file;
804     }
805 
806     lockmgr(&kld_lock, LK_EXCLUSIVE);
807     error = linker_load_module(kldname, modname, NULL, NULL, &lf);
808     lockmgr(&kld_lock, LK_RELEASE);
809     if (error)
810 	goto out;
811 
812     lf->userrefs++;
813     sysmsg->sysmsg_result = lf->id;
814 
815 out:
816     if (file)
817 	kfree(file, M_TEMP);
818     return error;
819 }
820 
821 /*
822  * MPALMOSTSAFE
823  */
824 int
825 sys_kldunload(struct sysmsg *sysmsg, const struct kldunload_args *uap)
826 {
827     struct thread *td = curthread;
828     linker_file_t lf;
829     int error = 0;
830 
831     if (securelevel > 0 || kernel_mem_readonly)	/* redundant, but that's OK */
832 	return EPERM;
833 
834     if ((error = priv_check(td, PRIV_KLD_UNLOAD)) != 0)
835 	return error;
836 
837     lockmgr(&kld_lock, LK_EXCLUSIVE);
838     lf = linker_find_file_by_id(uap->fileid);
839     if (lf) {
840 	KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
841 	if (lf->userrefs == 0) {
842 	    kprintf("linkerunload: attempt to unload file that was loaded by the kernel\n");
843 	    error = EBUSY;
844 	    goto out;
845 	}
846 	lf->userrefs--;
847 	error = linker_file_unload(lf);
848 	if (error)
849 	    lf->userrefs++;
850     } else {
851 	error = ENOENT;
852     }
853 out:
854     lockmgr(&kld_lock, LK_RELEASE);
855 
856     return error;
857 }
858 
859 /*
860  * MPALMOSTSAFE
861  */
862 int
863 sys_kldfind(struct sysmsg *sysmsg, const struct kldfind_args *uap)
864 {
865     char *filename = NULL, *modulename;
866     linker_file_t lf;
867     int error;
868 
869     sysmsg->sysmsg_result = -1;
870 
871     filename = kmalloc(MAXPATHLEN, M_TEMP, M_WAITOK);
872     if ((error = copyinstr(uap->file, filename, MAXPATHLEN, NULL)) != 0)
873 	goto out;
874 
875     modulename = rindex(filename, '/');
876     if (modulename == NULL)
877 	modulename = filename;
878 
879     lockmgr(&kld_lock, LK_EXCLUSIVE);
880     lf = linker_find_file_by_name(modulename);
881     if (lf)
882 	sysmsg->sysmsg_result = lf->id;
883     else
884 	error = ENOENT;
885     lockmgr(&kld_lock, LK_RELEASE);
886 
887 out:
888     if (filename)
889 	kfree(filename, M_TEMP);
890     return error;
891 }
892 
893 /*
894  * MPALMOSTSAFE
895  */
896 int
897 sys_kldnext(struct sysmsg *sysmsg, const struct kldnext_args *uap)
898 {
899     linker_file_t lf;
900     int error = 0;
901 
902     lockmgr(&kld_lock, LK_EXCLUSIVE);
903     if (uap->fileid == 0) {
904 	lf = TAILQ_FIRST(&linker_files);
905     } else {
906 	lf = linker_find_file_by_id(uap->fileid);
907 	if (lf == NULL) {
908 	    error = ENOENT;
909 	    goto out;
910 	}
911 	lf = TAILQ_NEXT(lf, link);
912     }
913 
914     /* Skip partially loaded files. */
915     while (lf != NULL && !(lf->flags & LINKER_FILE_LINKED)) {
916 	lf = TAILQ_NEXT(lf, link);
917     }
918 
919     if (lf)
920 	sysmsg->sysmsg_result = lf->id;
921     else
922 	sysmsg->sysmsg_result = 0;
923 
924 out:
925     lockmgr(&kld_lock, LK_RELEASE);
926 
927     return error;
928 }
929 
930 /*
931  * MPALMOSTSAFE
932  */
933 int
934 sys_kldstat(struct sysmsg *sysmsg, const struct kldstat_args *uap)
935 {
936     linker_file_t lf;
937     int error = 0;
938     int version;
939     struct kld_file_stat* stat;
940     int namelen;
941 
942     lockmgr(&kld_lock, LK_EXCLUSIVE);
943     lf = linker_find_file_by_id(uap->fileid);
944     if (!lf) {
945 	error = ENOENT;
946 	goto out;
947     }
948 
949     stat = uap->stat;
950 
951     /*
952      * Check the version of the user's structure.
953      */
954     if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
955 	goto out;
956     if (version != sizeof(struct kld_file_stat)) {
957 	error = EINVAL;
958 	goto out;
959     }
960 
961     namelen = strlen(lf->filename) + 1;
962     if (namelen > MAXPATHLEN)
963 	namelen = MAXPATHLEN;
964     if ((error = copyout(lf->filename, stat->name, namelen)) != 0)
965 	goto out;
966 
967     namelen = strlen(lf->pathname) + 1;
968     if (namelen > MAXPATHLEN)
969 	namelen = MAXPATHLEN;
970     if ((error = copyout(lf->pathname, stat->pathname, namelen)) != 0)
971 	goto out;
972 
973     if ((error = copyout(&lf->refs, &stat->refs, sizeof(int))) != 0)
974 	goto out;
975     if ((error = copyout(&lf->id, &stat->id, sizeof(int))) != 0)
976 	goto out;
977     if ((error = copyout(&lf->address, &stat->address, sizeof(caddr_t))) != 0)
978 	goto out;
979     if ((error = copyout(&lf->size, &stat->size, sizeof(size_t))) != 0)
980 	goto out;
981 
982     sysmsg->sysmsg_result = 0;
983 
984 out:
985     lockmgr(&kld_lock, LK_RELEASE);
986 
987     return error;
988 }
989 
990 /*
991  * MPALMOSTSAFE
992  */
993 int
994 sys_kldfirstmod(struct sysmsg *sysmsg, const struct kldfirstmod_args *uap)
995 {
996     linker_file_t lf;
997     int error = 0;
998 
999     lockmgr(&kld_lock, LK_EXCLUSIVE);
1000     lf = linker_find_file_by_id(uap->fileid);
1001     if (lf) {
1002 	if (TAILQ_FIRST(&lf->modules))
1003 	    sysmsg->sysmsg_result = module_getid(TAILQ_FIRST(&lf->modules));
1004 	else
1005 	    sysmsg->sysmsg_result = 0;
1006     } else {
1007 	error = ENOENT;
1008     }
1009     lockmgr(&kld_lock, LK_RELEASE);
1010 
1011     return error;
1012 }
1013 
1014 /*
1015  * MPALMOSTSAFE
1016  */
1017 int
1018 sys_kldsym(struct sysmsg *sysmsg, const struct kldsym_args *uap)
1019 {
1020     char *symstr = NULL;
1021     c_linker_sym_t sym;
1022     linker_symval_t symval;
1023     linker_file_t lf;
1024     struct kld_sym_lookup lookup;
1025     int error = 0;
1026 
1027     lockmgr(&kld_lock, LK_EXCLUSIVE);
1028     if ((error = copyin(uap->data, &lookup, sizeof(lookup))) != 0)
1029 	goto out;
1030     if (lookup.version != sizeof(lookup) || uap->cmd != KLDSYM_LOOKUP) {
1031 	error = EINVAL;
1032 	goto out;
1033     }
1034 
1035     symstr = kmalloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1036     if ((error = copyinstr(lookup.symname, symstr, MAXPATHLEN, NULL)) != 0)
1037 	goto out;
1038 
1039     if (uap->fileid != 0) {
1040 	lf = linker_find_file_by_id(uap->fileid);
1041 	if (lf == NULL) {
1042 	    error = ENOENT;
1043 	    goto out;
1044 	}
1045 	if (lf->ops->lookup_symbol(lf, symstr, &sym) == 0 &&
1046 	    lf->ops->symbol_values(lf, sym, &symval) == 0) {
1047 	    lookup.symvalue = (uintptr_t)symval.value;
1048 	    lookup.symsize = symval.size;
1049 	    error = copyout(&lookup, uap->data, sizeof(lookup));
1050 	} else
1051 	    error = ENOENT;
1052     } else {
1053 	TAILQ_FOREACH(lf, &linker_files, link) {
1054 	    if (lf->ops->lookup_symbol(lf, symstr, &sym) == 0 &&
1055 		lf->ops->symbol_values(lf, sym, &symval) == 0) {
1056 		lookup.symvalue = (uintptr_t)symval.value;
1057 		lookup.symsize = symval.size;
1058 		error = copyout(&lookup, uap->data, sizeof(lookup));
1059 		break;
1060 	    }
1061 	}
1062 	if (!lf)
1063 	    error = ENOENT;
1064     }
1065 out:
1066     lockmgr(&kld_lock, LK_RELEASE);
1067     if (symstr)
1068 	kfree(symstr, M_TEMP);
1069 
1070     return error;
1071 }
1072 
1073 /*
1074  * Preloaded module support
1075  */
1076 
1077 static modlist_t
1078 modlist_lookup(const char *name, int ver)
1079 {
1080     modlist_t	    mod;
1081 
1082     TAILQ_FOREACH(mod, &found_modules, link) {
1083 	if (strcmp(mod->name, name) == 0 && (ver == 0 || mod->version == ver))
1084 	    return (mod);
1085     }
1086     return (NULL);
1087 }
1088 
1089 static modlist_t
1090 modlist_lookup2(const char *name, struct mod_depend *verinfo)
1091 {
1092     modlist_t	    mod, bestmod;
1093     int		    ver;
1094 
1095     if (verinfo == NULL)
1096 	return (modlist_lookup(name, 0));
1097     bestmod = NULL;
1098     TAILQ_FOREACH(mod, &found_modules, link) {
1099 	if (strcmp(mod->name, name) != 0)
1100 	    continue;
1101 	ver = mod->version;
1102 	if (ver == verinfo->md_ver_preferred)
1103 	    return (mod);
1104 	if (ver >= verinfo->md_ver_minimum &&
1105 		ver <= verinfo->md_ver_maximum &&
1106 		(bestmod == NULL || ver > bestmod->version))
1107 	    bestmod = mod;
1108     }
1109     return (bestmod);
1110 }
1111 
1112 int
1113 linker_reference_module(const char *modname, struct mod_depend *verinfo,
1114     linker_file_t *result)
1115 {
1116     modlist_t mod;
1117     int error;
1118 
1119     lockmgr(&llf_lock, LK_SHARED);
1120     if ((mod = modlist_lookup2(modname, verinfo)) != NULL) {
1121         *result = mod->container;
1122         (*result)->refs++;
1123         lockmgr(&llf_lock, LK_RELEASE);
1124         return (0);
1125     }
1126 
1127     lockmgr(&llf_lock, LK_RELEASE);
1128     /*lockmgr(&kld_lock, LK_EXCLUSIVE);*/
1129     error = linker_load_module(NULL, modname, NULL, verinfo, result);
1130     /*lockmgr(&kld_lock, LK_RELEASE);*/
1131 
1132     return (error);
1133 }
1134 
1135 int
1136 linker_release_module(const char *modname, struct mod_depend *verinfo,
1137     linker_file_t lf)
1138 {
1139     modlist_t mod;
1140     int error;
1141 
1142     lockmgr(&llf_lock, LK_SHARED);
1143     if (lf == NULL) {
1144         KASSERT(modname != NULL,
1145             ("linker_release_module: no file or name"));
1146         mod = modlist_lookup2(modname, verinfo);
1147         if (mod == NULL) {
1148             lockmgr(&llf_lock, LK_RELEASE);
1149             return (ESRCH);
1150         }
1151         lf = mod->container;
1152     } else
1153         KASSERT(modname == NULL && verinfo == NULL,
1154             ("linker_release_module: both file and name"));
1155     lockmgr(&llf_lock, LK_RELEASE);
1156     /*lockmgr(&kld_lock, LK_EXCLUSIVE);*/
1157     error = linker_file_unload(lf);
1158     /*lockmgr(&kld_lock, LK_RELEASE);*/
1159 
1160     return (error);
1161 }
1162 
1163 static modlist_t
1164 modlist_newmodule(const char *modname, int version, linker_file_t container)
1165 {
1166     modlist_t	    mod;
1167 
1168     mod = kmalloc(sizeof(struct modlist), M_LINKER, M_NOWAIT | M_ZERO);
1169     if (mod == NULL)
1170 	panic("no memory for module list");
1171     mod->container = container;
1172     mod->name = modname;
1173     mod->version = version;
1174     TAILQ_INSERT_TAIL(&found_modules, mod, link);
1175     return (mod);
1176 }
1177 
1178 static void
1179 linker_addmodules(linker_file_t lf, struct mod_metadata **start,
1180 		  struct mod_metadata **stop, int preload)
1181 {
1182     struct mod_metadata *mp, **mdp;
1183     const char     *modname;
1184     int		    ver;
1185 
1186     for (mdp = start; mdp < stop; mdp++) {
1187 	mp = *mdp;
1188 	if (mp->md_type != MDT_VERSION)
1189 	    continue;
1190 	modname = mp->md_cval;
1191 	ver = ((struct mod_version *)mp->md_data)->mv_version;
1192 	if (modlist_lookup(modname, ver) != NULL) {
1193 	    kprintf("module %s already present!\n", modname);
1194 	    /* XXX what can we do? this is a build error. :-( */
1195 	    continue;
1196 	}
1197 	modlist_newmodule(modname, ver, lf);
1198     }
1199 }
1200 
1201 static void
1202 linker_preload(void* arg)
1203 {
1204     caddr_t		modptr;
1205     const char		*modname, *nmodname;
1206     char		*modtype;
1207     linker_file_t	lf, nlf;
1208     linker_class_t	lc;
1209     int			error;
1210     linker_file_list_t loaded_files;
1211     linker_file_list_t depended_files;
1212     struct mod_metadata *mp, *nmp;
1213     struct mod_metadata **start, **stop, **mdp, **nmdp;
1214     struct mod_depend *verinfo;
1215     int nver;
1216     int resolves;
1217     modlist_t mod;
1218     struct sysinit	**si_start, **si_stop;
1219 
1220     TAILQ_INIT(&loaded_files);
1221     TAILQ_INIT(&depended_files);
1222     TAILQ_INIT(&found_modules);
1223 
1224     modptr = NULL;
1225     while ((modptr = preload_search_next_name(modptr)) != NULL) {
1226 	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
1227 	modtype = (char *)preload_search_info(modptr, MODINFO_TYPE);
1228 	if (modname == NULL) {
1229 	    kprintf("Preloaded module at %p does not have a name!\n", modptr);
1230 	    continue;
1231 	}
1232 	if (modtype == NULL) {
1233 	    kprintf("Preloaded module at %p does not have a type!\n", modptr);
1234 	    continue;
1235 	}
1236 
1237 	if (bootverbose)
1238 		kprintf("Preloaded %s \"%s\" at %p.\n", modtype, modname, modptr);
1239 	lf = NULL;
1240 	TAILQ_FOREACH(lc, &classes, link) {
1241 	    error = lc->ops->preload_file(modname, &lf);
1242 	    if (!error)
1243 		break;
1244 	    lf = NULL;
1245 	}
1246 	if (lf)
1247 		TAILQ_INSERT_TAIL(&loaded_files, lf, loaded);
1248     }
1249 
1250     /*
1251      * First get a list of stuff in the kernel.
1252      */
1253     if (linker_file_lookup_set(linker_kernel_file, MDT_SETNAME, &start,
1254 			       &stop, NULL) == 0)
1255 	linker_addmodules(linker_kernel_file, start, stop, 1);
1256 
1257     /*
1258      * This is a once-off kinky bubble sort to resolve relocation
1259      * dependency requirements.
1260      */
1261 restart:
1262     TAILQ_FOREACH(lf, &loaded_files, loaded) {
1263 	error = linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop, NULL);
1264 	/*
1265 	 * First, look to see if we would successfully link with this
1266 	 * stuff.
1267 	 */
1268 	resolves = 1;		/* unless we know otherwise */
1269 	if (!error) {
1270 	    for (mdp = start; mdp < stop; mdp++) {
1271 		mp = *mdp;
1272 		if (mp->md_type != MDT_DEPEND)
1273 		    continue;
1274 		modname = mp->md_cval;
1275 		verinfo = mp->md_data;
1276 		for (nmdp = start; nmdp < stop; nmdp++) {
1277 		    nmp = *nmdp;
1278 		    if (nmp->md_type != MDT_VERSION)
1279 			continue;
1280 		    nmodname = nmp->md_cval;
1281 		    if (strcmp(modname, nmodname) == 0)
1282 			break;
1283 		}
1284 		if (nmdp < stop)/* it's a self reference */
1285 		    continue;
1286 
1287 		/*
1288 		 * ok, the module isn't here yet, we
1289 		 * are not finished
1290 		 */
1291 		if (modlist_lookup2(modname, verinfo) == NULL)
1292 		    resolves = 0;
1293 	    }
1294 	}
1295 	/*
1296 	 * OK, if we found our modules, we can link.  So, "provide"
1297 	 * the modules inside and add it to the end of the link order
1298 	 * list.
1299 	 */
1300 	if (resolves) {
1301 	    if (!error) {
1302 		for (mdp = start; mdp < stop; mdp++) {
1303 		    mp = *mdp;
1304 		    if (mp->md_type != MDT_VERSION)
1305 			continue;
1306 		    modname = mp->md_cval;
1307 		    nver = ((struct mod_version *)mp->md_data)->mv_version;
1308 		    if (modlist_lookup(modname, nver) != NULL) {
1309 			kprintf("module %s already present!\n", modname);
1310 			TAILQ_REMOVE(&loaded_files, lf, loaded);
1311 			linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */ );
1312 			/* we changed tailq next ptr */
1313 			goto restart;
1314 		    }
1315 		    modlist_newmodule(modname, nver, lf);
1316 		}
1317 	    }
1318 	    TAILQ_REMOVE(&loaded_files, lf, loaded);
1319 	    TAILQ_INSERT_TAIL(&depended_files, lf, loaded);
1320 	    /*
1321 	     * Since we provided modules, we need to restart the
1322 	     * sort so that the previous files that depend on us
1323 	     * have a chance. Also, we've busted the tailq next
1324 	     * pointer with the REMOVE.
1325 	     */
1326 	    goto restart;
1327 	}
1328     }
1329 
1330     /*
1331      * At this point, we check to see what could not be resolved..
1332      */
1333     while ((lf = TAILQ_FIRST(&loaded_files)) != NULL) {
1334 	TAILQ_REMOVE(&loaded_files, lf, loaded);
1335 	kprintf("KLD file %s is missing dependencies\n", lf->filename);
1336 	linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */ );
1337     }
1338 
1339     /*
1340      * We made it. Finish off the linking in the order we determined.
1341      */
1342     TAILQ_FOREACH_MUTABLE(lf, &depended_files, loaded, nlf) {
1343 	if (linker_kernel_file) {
1344 	    linker_kernel_file->refs++;
1345 	    linker_file_add_dependancy(lf, linker_kernel_file);
1346 	}
1347 	lf->userrefs++;
1348 
1349 	error = linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop, NULL);
1350 	if (!error) {
1351 	    for (mdp = start; mdp < stop; mdp++) {
1352 		mp = *mdp;
1353 		if (mp->md_type != MDT_DEPEND)
1354 		    continue;
1355 		modname = mp->md_cval;
1356 		verinfo = mp->md_data;
1357 		mod = modlist_lookup2(modname, verinfo);
1358 		/* Don't count self-dependencies */
1359 		if (lf == mod->container)
1360 		    continue;
1361 		mod->container->refs++;
1362 		linker_file_add_dependancy(lf, mod->container);
1363 	    }
1364 	}
1365 	/*
1366 	 * Now do relocation etc using the symbol search paths
1367 	 * established by the dependencies
1368 	 */
1369 	error = lf->ops->preload_finish(lf);
1370 	if (error) {
1371 	    TAILQ_REMOVE(&depended_files, lf, loaded);
1372 	    kprintf("KLD file %s - could not finalize loading\n",
1373 		    lf->filename);
1374 	    linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */);
1375 	    continue;
1376 	}
1377 	linker_file_register_modules(lf);
1378 	if (linker_file_lookup_set(lf, "sysinit_set", &si_start, &si_stop, NULL) == 0)
1379 	    sysinit_add(si_start, si_stop);
1380 	linker_file_register_sysctls(lf);
1381 	lf->flags |= LINKER_FILE_LINKED;
1382     }
1383     /* woohoo! we made it! */
1384 }
1385 
1386 SYSINIT(preload, SI_BOOT2_KLD, SI_ORDER_MIDDLE, linker_preload, 0);
1387 
1388 /*
1389  * Search for a not-loaded module by name.
1390  *
1391  * Modules may be found in the following locations:
1392  *
1393  * - preloaded (result is just the module name)
1394  * - on disk (result is full path to module)
1395  *
1396  * If the module name is qualified in any way (contains path, etc.)
1397  * the we simply return a copy of it.
1398  *
1399  * The search path can be manipulated via sysctl.  Note that we use the ';'
1400  * character as a separator to be consistent with the bootloader.
1401  */
1402 
1403 static char linker_path[MAXPATHLEN] = "/boot;/boot/modules;/;/modules";
1404 
1405 SYSCTL_STRING(_kern, OID_AUTO, module_path, CTLFLAG_RW, linker_path,
1406 	      sizeof(linker_path), "module load search path");
1407 TUNABLE_STR("module_path", linker_path, sizeof(linker_path));
1408 
1409 char *
1410 linker_search_path(const char *name)
1411 {
1412     struct nlookupdata	nd;
1413     char		*cp, *ep, *result;
1414     size_t		name_len, prefix_len;
1415     size_t		result_len;
1416     int			sep;
1417     int			error;
1418     enum vtype		type;
1419     const char *exts[] = { "", ".ko", NULL };
1420     const char **ext;
1421 
1422     /* qualified at all? */
1423     if (index(name, '/'))
1424 	return(linker_strdup(name));
1425 
1426     /* traverse the linker path */
1427     cp = linker_path;
1428     name_len = strlen(name);
1429     for (;;) {
1430 
1431 	/* find the end of this component */
1432 	for (ep = cp; (*ep != 0) && (*ep != ';'); ep++)
1433 	    ;
1434 	prefix_len = ep - cp;
1435 	/* if this component doesn't end with a slash, add one */
1436 	if (ep == cp || *(ep - 1) != '/')
1437 	    sep = 1;
1438 	else
1439 	    sep = 0;
1440 
1441 	/*
1442 	 * +2+3 : possible separator, plus terminator + possible extension.
1443 	 */
1444 	result = kmalloc(prefix_len + name_len + 2+3, M_LINKER, M_WAITOK);
1445 
1446 	strncpy(result, cp, prefix_len);
1447 	if (sep)
1448 	    result[prefix_len++] = '/';
1449 	strcpy(result + prefix_len, name);
1450 
1451 	result_len = strlen(result);
1452 	for (ext = exts; *ext != NULL; ext++) {
1453 	    strcpy(result + result_len, *ext);
1454 
1455 	    /*
1456 	     * Attempt to open the file, and return the path if we succeed and it's
1457 	     * a regular file.
1458 	     */
1459 	    error = nlookup_init(&nd, result, UIO_SYSSPACE, NLC_FOLLOW|NLC_LOCKVP);
1460 	    if (error == 0)
1461 		error = vn_open(&nd, NULL, FREAD, 0);
1462 	    if (error == 0) {
1463 		type = nd.nl_open_vp->v_type;
1464 		if (type == VREG) {
1465 		    nlookup_done(&nd);
1466 		    return (result);
1467 		}
1468 	    }
1469 	    nlookup_done(&nd);
1470 	}
1471 
1472 	kfree(result, M_LINKER);
1473 
1474 	if (*ep == 0)
1475 	    break;
1476 	cp = ep + 1;
1477     }
1478     return(NULL);
1479 }
1480 
1481 /*
1482  * Find a file which contains given module and load it, if "parent" is not
1483  * NULL, register a reference to it.
1484  */
1485 static int
1486 linker_load_module(const char *kldname, const char *modname,
1487 		   struct linker_file *parent, struct mod_depend *verinfo,
1488 		   struct linker_file **lfpp)
1489 {
1490     linker_file_t   lfdep;
1491     const char     *filename;
1492     char           *pathname;
1493     int		    error;
1494 
1495     if (modname == NULL) {
1496 	/*
1497 	 * We have to load KLD
1498 	 */
1499 	KASSERT(verinfo == NULL, ("linker_load_module: verinfo is not NULL"));
1500 	pathname = linker_search_path(kldname);
1501     } else {
1502 	if (modlist_lookup2(modname, verinfo) != NULL)
1503 	    return (EEXIST);
1504 	if (kldname != NULL)
1505 	{
1506 	    pathname = linker_strdup(kldname);
1507 	}
1508 	else if (rootvnode == NULL)
1509 	    pathname = NULL;
1510 	else
1511 	{
1512 	    pathname = linker_search_path(modname);
1513 	}
1514 #if 0
1515 	/*
1516 	 * Need to find a KLD with required module
1517 	 */
1518 	pathname = linker_search_module(modname,
1519 					strlen(modname), verinfo);
1520 #endif
1521     }
1522     if (pathname == NULL)
1523 	return (ENOENT);
1524 
1525     /*
1526      * Can't load more than one file with the same basename XXX:
1527      * Actually it should be possible to have multiple KLDs with
1528      * the same basename but different path because they can
1529      * provide different versions of the same modules.
1530      */
1531     filename = rindex(pathname, '/');
1532     if (filename == NULL)
1533 	filename = pathname;
1534     else
1535 	filename++;
1536     if (linker_find_file_by_name(filename))
1537 	error = EEXIST;
1538     else
1539 	do {
1540 	    error = linker_load_file(pathname, &lfdep);
1541 	    if (error)
1542 		break;
1543 	    if (modname && verinfo && modlist_lookup2(modname, verinfo) == NULL) {
1544 		linker_file_unload(lfdep /* , LINKER_UNLOAD_FORCE */ );
1545 		error = ENOENT;
1546 		break;
1547 	    }
1548 	    if (parent) {
1549 		linker_file_add_dependancy(parent, lfdep);
1550 	    }
1551 	    if (lfpp)
1552 		*lfpp = lfdep;
1553 	} while (0);
1554     kfree(pathname, M_LINKER);
1555     return (error);
1556 }
1557 
1558 /*
1559  * This routine is responsible for finding dependencies of userland initiated
1560  * kldload(2)'s of files.
1561  */
1562 int
1563 linker_load_dependencies(linker_file_t lf)
1564 {
1565     linker_file_t   lfdep;
1566     struct mod_metadata **start, **stop, **mdp, **nmdp;
1567     struct mod_metadata *mp, *nmp;
1568     struct mod_depend *verinfo;
1569     modlist_t	    mod;
1570     const char     *modname, *nmodname;
1571     int		    ver, error = 0, count;
1572 
1573     /*
1574      * All files are dependant on /kernel.
1575      */
1576     if (linker_kernel_file) {
1577 	linker_kernel_file->refs++;
1578 	linker_file_add_dependancy(lf, linker_kernel_file);
1579     }
1580     if (linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop, &count) != 0)
1581 	return (0);
1582     for (mdp = start; mdp < stop; mdp++) {
1583 	mp = *mdp;
1584 	if (mp->md_type != MDT_VERSION)
1585 	    continue;
1586 	modname = mp->md_cval;
1587 	ver = ((struct mod_version *)mp->md_data)->mv_version;
1588 	mod = modlist_lookup(modname, ver);
1589 	if (mod != NULL) {
1590 	    kprintf("interface %s.%d already present in the KLD '%s'!\n",
1591 		    modname, ver, mod->container->filename);
1592 	    return (EEXIST);
1593 	}
1594     }
1595 
1596     for (mdp = start; mdp < stop; mdp++) {
1597 	mp = *mdp;
1598 	if (mp->md_type != MDT_DEPEND)
1599 	    continue;
1600 	modname = mp->md_cval;
1601 	verinfo = mp->md_data;
1602 	nmodname = NULL;
1603 	for (nmdp = start; nmdp < stop; nmdp++) {
1604 	    nmp = *nmdp;
1605 	    if (nmp->md_type != MDT_VERSION)
1606 		continue;
1607 	    nmodname = nmp->md_cval;
1608 	    if (strcmp(modname, nmodname) == 0)
1609 		break;
1610 	}
1611 	if (nmdp < stop)	/* early exit, it's a self reference */
1612 	    continue;
1613 	mod = modlist_lookup2(modname, verinfo);
1614 	if (mod) {		/* woohoo, it's loaded already */
1615 	    lfdep = mod->container;
1616 	    lfdep->refs++;
1617 	    linker_file_add_dependancy(lf, lfdep);
1618 	    continue;
1619 	}
1620 	error = linker_load_module(NULL, modname, lf, verinfo, NULL);
1621 	if (error) {
1622 	    kprintf("KLD %s: depends on %s - not available or version mismatch\n",
1623 		    lf->filename, modname);
1624 	    break;
1625 	}
1626     }
1627 
1628     if (error)
1629 	return (error);
1630     linker_addmodules(lf, start, stop, 0);
1631     return (0);
1632 }
1633