xref: /freebsd/sys/kern/kern_linker.c (revision edfbe150804a4f40e8282786b00798359c07e652)
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  *	$Id: kern_linker.c,v 1.15 1998/11/06 15:10:17 peter 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/sysproto.h>
36 #include <sys/sysent.h>
37 #include <sys/proc.h>
38 #include <sys/lock.h>
39 #include <machine/cpu.h>
40 #include <machine/bootinfo.h>
41 #include <sys/module.h>
42 #include <sys/linker.h>
43 #include <sys/unistd.h>
44 #include <sys/fcntl.h>
45 #include <sys/libkern.h>
46 #include <sys/namei.h>
47 #include <sys/vnode.h>
48 #include <sys/sysctl.h>
49 
50 #ifdef KLD_DEBUG
51 int kld_debug = 0;
52 #endif
53 
54 MALLOC_DEFINE(M_LINKER, "kld", "kernel linker");
55 linker_file_t linker_current_file;
56 linker_file_t linker_kernel_file;
57 
58 static struct lock lock;	/* lock for the file list */
59 static linker_class_list_t classes;
60 static linker_file_list_t files;
61 static int next_file_id = 1;
62 
63 static void
64 linker_init(void* arg)
65 {
66     lockinit(&lock, PVM, "klink", 0, 0);
67     TAILQ_INIT(&classes);
68     TAILQ_INIT(&files);
69 }
70 
71 SYSINIT(linker, SI_SUB_KLD, SI_ORDER_FIRST, linker_init, 0);
72 
73 int
74 linker_add_class(const char* desc, void* priv,
75 		 struct linker_class_ops* ops)
76 {
77     linker_class_t lc;
78 
79     lc = malloc(sizeof(struct linker_class), M_LINKER, M_NOWAIT);
80     if (!lc)
81 	return ENOMEM;
82     bzero(lc, sizeof(*lc));
83 
84     lc->desc = desc;
85     lc->priv = priv;
86     lc->ops = ops;
87     TAILQ_INSERT_HEAD(&classes, lc, link);
88 
89     return 0;
90 }
91 
92 static void
93 linker_file_sysinit(linker_file_t lf)
94 {
95     struct linker_set* sysinits;
96     struct sysinit** sipp;
97     struct sysinit** xipp;
98     struct sysinit* save;
99     moduledata_t *moddata;
100 
101     KLD_DPF(FILE, ("linker_file_sysinit: calling SYSINITs for %s\n",
102 		   lf->filename));
103 
104     sysinits = (struct linker_set*)
105 	linker_file_lookup_symbol(lf, "sysinit_set", 0);
106 
107     KLD_DPF(FILE, ("linker_file_sysinit: SYSINITs %p\n", sysinits));
108     if (!sysinits)
109 	return;
110 
111     /* HACK ALERT! */
112     for (sipp = (struct sysinit **)sysinits->ls_items; *sipp; sipp++) {
113 	if ((*sipp)->func == module_register_init) {
114 	    moddata = (*sipp)->udata;
115 	    moddata->_file = lf;
116 	}
117     }
118 
119     /*
120      * Perform a bubble sort of the system initialization objects by
121      * their subsystem (primary key) and order (secondary key).
122      *
123      * Since some things care about execution order, this is the
124      * operation which ensures continued function.
125      */
126     for (sipp = (struct sysinit **)sysinits->ls_items; *sipp; sipp++) {
127 	for (xipp = sipp + 1; *xipp; xipp++) {
128 	    if ((*sipp)->subsystem <= (*xipp)->subsystem ||
129 		 ((*sipp)->subsystem == (*xipp)->subsystem &&
130 		  (*sipp)->order <= (*xipp)->order))
131 		continue;	/* skip*/
132 	    save = *sipp;
133 	    *sipp = *xipp;
134 	    *xipp = save;
135 	}
136     }
137 
138 
139     /*
140      * Traverse the (now) ordered list of system initialization tasks.
141      * Perform each task, and continue on to the next task.
142      */
143     for (sipp = (struct sysinit **)sysinits->ls_items; *sipp; sipp++) {
144 	if ((*sipp)->subsystem == SI_SUB_DUMMY)
145 	    continue;	/* skip dummy task(s)*/
146 
147 	switch ((*sipp)->type) {
148 	case SI_TYPE_DEFAULT:
149 	    /* no special processing*/
150 	    (*((*sipp)->func))((*sipp)->udata);
151 	    break;
152 
153 	case SI_TYPE_KTHREAD:
154 #if !defined(SMP)
155 	    /* kernel thread*/
156 	    if (fork1(&proc0, RFFDG|RFPROC|RFMEM))
157 		panic("fork kernel thread");
158 	    cpu_set_fork_handler(pfind(proc0.p_retval[0]),
159 		(*sipp)->func, (*sipp)->udata);
160 	    break;
161 #endif
162 
163 	case SI_TYPE_KPROCESS:
164 	    /* kernel thread*/
165 	    if (fork1(&proc0, RFFDG|RFPROC))
166 		panic("fork kernel process");
167 	    cpu_set_fork_handler(pfind(proc0.p_retval[0]),
168 		(*sipp)->func, (*sipp)->udata);
169 	    break;
170 
171 	default:
172 	    panic ("linker_file_sysinit: unrecognized init type");
173 	}
174     }
175 }
176 
177 static void
178 linker_file_sysuninit(linker_file_t lf)
179 {
180     struct linker_set* sysuninits;
181     struct sysinit** sipp;
182     struct sysinit** xipp;
183     struct sysinit* save;
184 
185     KLD_DPF(FILE, ("linker_file_sysuninit: calling SYSUNINITs for %s\n",
186 		   lf->filename));
187 
188     sysuninits = (struct linker_set*)
189 	linker_file_lookup_symbol(lf, "sysuninit_set", 0);
190 
191     KLD_DPF(FILE, ("linker_file_sysuninit: SYSUNINITs %p\n", sysuninits));
192     if (!sysuninits)
193 	return;
194 
195     /*
196      * Perform a reverse bubble sort of the system initialization objects
197      * by their subsystem (primary key) and order (secondary key).
198      *
199      * Since some things care about execution order, this is the
200      * operation which ensures continued function.
201      */
202     for (sipp = (struct sysinit **)sysuninits->ls_items; *sipp; sipp++) {
203 	for (xipp = sipp + 1; *xipp; xipp++) {
204 	    if ((*sipp)->subsystem >= (*xipp)->subsystem ||
205 		 ((*sipp)->subsystem == (*xipp)->subsystem &&
206 		  (*sipp)->order >= (*xipp)->order))
207 		continue;	/* skip*/
208 	    save = *sipp;
209 	    *sipp = *xipp;
210 	    *xipp = save;
211 	}
212     }
213 
214 
215     /*
216      * Traverse the (now) ordered list of system initialization tasks.
217      * Perform each task, and continue on to the next task.
218      */
219     for (sipp = (struct sysinit **)sysuninits->ls_items; *sipp; sipp++) {
220 	if ((*sipp)->subsystem == SI_SUB_DUMMY)
221 	    continue;	/* skip dummy task(s)*/
222 
223 	switch ((*sipp)->type) {
224 	case SI_TYPE_DEFAULT:
225 	    /* no special processing*/
226 	    (*((*sipp)->func))((*sipp)->udata);
227 	    break;
228 
229 	default:
230 	    panic("linker_file_sysuninit: unrecognized uninit type");
231 	}
232     }
233 }
234 
235 int
236 linker_load_file(const char* filename, linker_file_t* result)
237 {
238     linker_class_t lc;
239     linker_file_t lf;
240     int error = 0;
241     char *koname = NULL;
242 
243     lf = linker_find_file_by_name(filename);
244     if (lf) {
245 	KLD_DPF(FILE, ("linker_load_file: file %s is already loaded, incrementing refs\n", filename));
246 	*result = lf;
247 	lf->refs++;
248 	goto out;
249     }
250 
251     koname = malloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
252     if (koname == NULL) {
253 	error = ENOMEM;
254 	goto out;
255     }
256     sprintf(koname, "%s.ko", filename);
257     lf = NULL;
258     for (lc = TAILQ_FIRST(&classes); lc; lc = TAILQ_NEXT(lc, link)) {
259 	KLD_DPF(FILE, ("linker_load_file: trying to load %s as %s\n",
260 		       filename, lc->desc));
261 	error = lc->ops->load_file(koname, &lf);
262 	if (lf == NULL && error && error != ENOENT)
263 	    goto out;
264 	if (lf == NULL)
265 	    error = lc->ops->load_file(filename, &lf);
266 	if (lf == NULL && error && error != ENOENT)
267 	    goto out;
268 	if (lf) {
269 	    linker_file_sysinit(lf);
270 
271 	    *result = lf;
272 	    error = 0;
273 	    goto out;
274 	}
275     }
276     error = ENOEXEC;		/* format not recognised */
277 
278 out:
279     if (koname)
280 	free(koname, M_LINKER);
281     return error;
282 }
283 
284 linker_file_t
285 linker_find_file_by_name(const char* filename)
286 {
287     linker_file_t lf = 0;
288     char *koname;
289 
290     koname = malloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
291     if (koname == NULL)
292 	goto out;
293     sprintf(koname, "%s.ko", filename);
294 
295     lockmgr(&lock, LK_SHARED, 0, curproc);
296     for (lf = TAILQ_FIRST(&files); lf; lf = TAILQ_NEXT(lf, link)) {
297 	if (!strcmp(lf->filename, koname))
298 	    break;
299 	if (!strcmp(lf->filename, filename))
300 	    break;
301     }
302     lockmgr(&lock, LK_RELEASE, 0, curproc);
303 
304 out:
305     if (koname)
306 	free(koname, M_LINKER);
307     return lf;
308 }
309 
310 linker_file_t
311 linker_find_file_by_id(int fileid)
312 {
313     linker_file_t lf = 0;
314 
315     lockmgr(&lock, LK_SHARED, 0, curproc);
316     for (lf = TAILQ_FIRST(&files); lf; lf = TAILQ_NEXT(lf, link))
317 	if (lf->id == fileid)
318 	    break;
319     lockmgr(&lock, LK_RELEASE, 0, curproc);
320 
321     return lf;
322 }
323 
324 linker_file_t
325 linker_make_file(const char* pathname, void* priv, struct linker_file_ops* ops)
326 {
327     linker_file_t lf = 0;
328     int namelen;
329     const char *filename;
330 
331     filename = rindex(pathname, '/');
332     if (filename && filename[1])
333 	filename++;
334     else
335 	filename = pathname;
336 
337     KLD_DPF(FILE, ("linker_make_file: new file, filename=%s\n", filename));
338     lockmgr(&lock, LK_EXCLUSIVE|LK_RETRY, 0, curproc);
339     namelen = strlen(filename) + 1;
340     lf = malloc(sizeof(struct linker_file) + namelen, M_LINKER, M_WAITOK);
341     if (!lf)
342 	goto out;
343     bzero(lf, sizeof(*lf));
344 
345     lf->refs = 1;
346     lf->userrefs = 0;
347     lf->filename = (char*) (lf + 1);
348     strcpy(lf->filename, filename);
349     lf->id = next_file_id++;
350     lf->ndeps = 0;
351     lf->deps = NULL;
352     STAILQ_INIT(&lf->common);
353     TAILQ_INIT(&lf->modules);
354 
355     lf->priv = priv;
356     lf->ops = ops;
357     TAILQ_INSERT_TAIL(&files, lf, link);
358 
359 out:
360     lockmgr(&lock, LK_RELEASE, 0, curproc);
361     return lf;
362 }
363 
364 int
365 linker_file_unload(linker_file_t file)
366 {
367     module_t mod, next;
368     struct common_symbol* cp;
369     int error = 0;
370     int i;
371 
372     KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
373     lockmgr(&lock, LK_EXCLUSIVE|LK_RETRY, 0, curproc);
374     if (file->refs == 1) {
375 	KLD_DPF(FILE, ("linker_file_unload: file is unloading, informing modules\n"));
376 	/*
377 	 * Inform any modules associated with this file.
378 	 */
379 	for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
380 	    next = module_getfnext(mod);
381 
382 	    /*
383 	     * Give the module a chance to veto the unload.
384 	     */
385 	    if (error = module_unload(mod)) {
386 		KLD_DPF(FILE, ("linker_file_unload: module %x vetoes unload\n",
387 			       mod));
388 		lockmgr(&lock, LK_RELEASE, 0, curproc);
389 		goto out;
390 	    }
391 
392 	    module_release(mod);
393 	}
394     }
395 
396     file->refs--;
397     if (file->refs > 0) {
398 	lockmgr(&lock, LK_RELEASE, 0, curproc);
399 	goto out;
400     }
401 
402     linker_file_sysuninit(file);
403 
404     TAILQ_REMOVE(&files, file, link);
405     lockmgr(&lock, LK_RELEASE, 0, curproc);
406 
407     for (i = 0; i < file->ndeps; i++)
408 	linker_file_unload(file->deps[i]);
409     free(file->deps, M_LINKER);
410 
411     for (cp = STAILQ_FIRST(&file->common); cp;
412 	 cp = STAILQ_FIRST(&file->common)) {
413 	STAILQ_REMOVE(&file->common, cp, common_symbol, link);
414 	free(cp, M_LINKER);
415     }
416 
417     file->ops->unload(file);
418     free(file, M_LINKER);
419 
420 out:
421     return error;
422 }
423 
424 int
425 linker_file_add_dependancy(linker_file_t file, linker_file_t dep)
426 {
427     linker_file_t* newdeps;
428 
429     newdeps = malloc((file->ndeps + 1) * sizeof(linker_file_t*),
430 		     M_LINKER, M_WAITOK);
431     if (newdeps == NULL)
432 	return ENOMEM;
433     bzero(newdeps, (file->ndeps + 1) * sizeof(linker_file_t*));
434 
435     if (file->deps) {
436 	bcopy(file->deps, newdeps, file->ndeps * sizeof(linker_file_t*));
437 	free(file->deps, M_LINKER);
438     }
439     file->deps = newdeps;
440     file->deps[file->ndeps] = dep;
441     file->ndeps++;
442 
443     return 0;
444 }
445 
446 caddr_t
447 linker_file_lookup_symbol(linker_file_t file, const char* name, int deps)
448 {
449     linker_sym_t sym;
450     linker_symval_t symval;
451     caddr_t address;
452     size_t common_size = 0;
453     int i;
454 
455     KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%x, name=%s, deps=%d\n",
456 		  file, name, deps));
457 
458     if (file->ops->lookup_symbol(file, name, &sym) == 0) {
459 	file->ops->symbol_values(file, sym, &symval);
460 	if (symval.value == 0)
461 	    /*
462 	     * For commons, first look them up in the dependancies and
463 	     * only allocate space if not found there.
464 	     */
465 	    common_size = symval.size;
466 	else {
467 	    KLD_DPF(SYM, ("linker_file_lookup_symbol: symbol.value=%x\n", symval.value));
468 	    return symval.value;
469 	}
470     }
471 
472     if (deps)
473 	for (i = 0; i < file->ndeps; i++) {
474 	    address = linker_file_lookup_symbol(file->deps[i], name, 0);
475 	    if (address) {
476 		KLD_DPF(SYM, ("linker_file_lookup_symbol: deps value=%x\n", address));
477 		return address;
478 	    }
479 	}
480 
481     if (common_size > 0) {
482 	/*
483 	 * This is a common symbol which was not found in the
484 	 * dependancies.  We maintain a simple common symbol table in
485 	 * the file object.
486 	 */
487 	struct common_symbol* cp;
488 
489 	for (cp = STAILQ_FIRST(&file->common); cp;
490 	     cp = STAILQ_NEXT(cp, link))
491 	    if (!strcmp(cp->name, name)) {
492 		KLD_DPF(SYM, ("linker_file_lookup_symbol: old common value=%x\n", cp->address));
493 		return cp->address;
494 	    }
495 
496 	/*
497 	 * Round the symbol size up to align.
498 	 */
499 	common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
500 	cp = malloc(sizeof(struct common_symbol)
501 		    + common_size
502 		    + strlen(name) + 1,
503 		    M_LINKER, M_WAITOK);
504 	if (!cp) {
505 	    KLD_DPF(SYM, ("linker_file_lookup_symbol: nomem\n"));
506 	    return 0;
507 	}
508 	bzero(cp, sizeof(struct common_symbol) + common_size + strlen(name)+ 1);
509 
510 	cp->address = (caddr_t) (cp + 1);
511 	cp->name = cp->address + common_size;
512 	strcpy(cp->name, name);
513 	bzero(cp->address, common_size);
514 	STAILQ_INSERT_TAIL(&file->common, cp, link);
515 
516 	KLD_DPF(SYM, ("linker_file_lookup_symbol: new common value=%x\n", cp->address));
517 	return cp->address;
518     }
519 
520     KLD_DPF(SYM, ("linker_file_lookup_symbol: fail\n"));
521     return 0;
522 }
523 
524 #ifdef DDB
525 /*
526  * DDB Helpers.  DDB has to look across multiple files with their own
527  * symbol tables and string tables.
528  *
529  * Note that we do not obey list locking protocols here.  We really don't
530  * need DDB to hang because somebody's got the lock held.  We'll take the
531  * chance that the files list is inconsistant instead.
532  */
533 
534 int
535 linker_ddb_lookup(char *symstr, linker_sym_t *sym)
536 {
537     linker_file_t lf;
538 
539     for (lf = TAILQ_FIRST(&files); lf; lf = TAILQ_NEXT(lf, link)) {
540 	if (lf->ops->lookup_symbol(lf, symstr, sym) == 0)
541 	    return 0;
542     }
543     return ENOENT;
544 }
545 
546 int
547 linker_ddb_search_symbol(caddr_t value, linker_sym_t *sym, long *diffp)
548 {
549     linker_file_t lf;
550     u_long off = (u_long)value;
551     u_long diff, bestdiff;
552     linker_sym_t best;
553     linker_sym_t es;
554 
555     best = 0;
556     bestdiff = off;
557     for (lf = TAILQ_FIRST(&files); lf; lf = TAILQ_NEXT(lf, link)) {
558 	if (lf->ops->search_symbol(lf, value, &es, &diff) != 0)
559 	    continue;
560 	if (es != 0 && diff < bestdiff) {
561 	    best = es;
562 	    bestdiff = diff;
563 	}
564 	if (bestdiff == 0)
565 	    break;
566     }
567     if (best) {
568 	*sym = best;
569 	*diffp = bestdiff;
570 	return 0;
571     } else {
572 	*sym = 0;
573 	*diffp = off;
574 	return ENOENT;
575     }
576 }
577 
578 int
579 linker_ddb_symbol_values(linker_sym_t sym, linker_symval_t *symval)
580 {
581     linker_file_t lf;
582 
583     for (lf = TAILQ_FIRST(&files); lf; lf = TAILQ_NEXT(lf, link)) {
584 	if (lf->ops->symbol_values(lf, sym, symval) == 0)
585 	    return 0;
586     }
587     return ENOENT;
588 }
589 
590 #endif
591 
592 /*
593  * Syscalls.
594  */
595 
596 int
597 kldload(struct proc* p, struct kldload_args* uap)
598 {
599     char* filename = NULL;
600     linker_file_t lf;
601     int error = 0;
602 
603     p->p_retval[0] = -1;
604 
605     if (securelevel > 0)
606 	return EPERM;
607 
608     if (error = suser(p->p_ucred, &p->p_acflag))
609 	return error;
610 
611     filename = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
612     if (error = copyinstr(SCARG(uap, file), filename, MAXPATHLEN, NULL))
613 	goto out;
614 
615     if (error = linker_load_file(filename, &lf))
616 	goto out;
617 
618     lf->userrefs++;
619     p->p_retval[0] = lf->id;
620 
621 out:
622     if (filename)
623 	free(filename, M_TEMP);
624     return error;
625 }
626 
627 int
628 kldunload(struct proc* p, struct kldunload_args* uap)
629 {
630     linker_file_t lf;
631     int error = 0;
632 
633     if (securelevel > 0)
634 	return EPERM;
635 
636     if (error = suser(p->p_ucred, &p->p_acflag))
637 	return error;
638 
639     lf = linker_find_file_by_id(SCARG(uap, fileid));
640     if (lf) {
641 	KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
642 	if (lf->userrefs == 0) {
643 	    printf("linkerunload: attempt to unload file which was not loaded by user\n");
644 	    error = EBUSY;
645 	    goto out;
646 	}
647 	lf->userrefs--;
648 	error = linker_file_unload(lf);
649     } else
650 	error = ENOENT;
651 
652 out:
653     return error;
654 }
655 
656 int
657 kldfind(struct proc* p, struct kldfind_args* uap)
658 {
659     char* filename = NULL;
660     linker_file_t lf;
661     int error = 0;
662 
663     p->p_retval[0] = -1;
664 
665     filename = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
666     if (error = copyinstr(SCARG(uap, file), filename, MAXPATHLEN, NULL))
667 	goto out;
668 
669     lf = linker_find_file_by_name(filename);
670     if (lf)
671 	p->p_retval[0] = lf->id;
672     else
673 	error = ENOENT;
674 
675 out:
676     if (filename)
677 	free(filename, M_TEMP);
678     return error;
679 }
680 
681 int
682 kldnext(struct proc* p, struct kldnext_args* uap)
683 {
684     linker_file_t lf;
685     int error = 0;
686 
687     if (SCARG(uap, fileid) == 0) {
688 	if (TAILQ_FIRST(&files))
689 	    p->p_retval[0] = TAILQ_FIRST(&files)->id;
690 	else
691 	    p->p_retval[0] = 0;
692 	return 0;
693     }
694 
695     lf = linker_find_file_by_id(SCARG(uap, fileid));
696     if (lf) {
697 	if (TAILQ_NEXT(lf, link))
698 	    p->p_retval[0] = TAILQ_NEXT(lf, link)->id;
699 	else
700 	    p->p_retval[0] = 0;
701     } else
702 	error = ENOENT;
703 
704     return error;
705 }
706 
707 int
708 kldstat(struct proc* p, struct kldstat_args* uap)
709 {
710     linker_file_t lf;
711     int error = 0;
712     int version;
713     struct kld_file_stat* stat;
714     int namelen;
715 
716     lf = linker_find_file_by_id(SCARG(uap, fileid));
717     if (!lf) {
718 	error = ENOENT;
719 	goto out;
720     }
721 
722     stat = SCARG(uap, stat);
723 
724     /*
725      * Check the version of the user's structure.
726      */
727     if (error = copyin(&stat->version, &version, sizeof(version)))
728 	goto out;
729     if (version != sizeof(struct kld_file_stat)) {
730 	error = EINVAL;
731 	goto out;
732     }
733 
734     namelen = strlen(lf->filename) + 1;
735     if (namelen > MAXPATHLEN)
736 	namelen = MAXPATHLEN;
737     if (error = copyout(lf->filename, &stat->name[0], namelen))
738 	goto out;
739     if (error = copyout(&lf->refs, &stat->refs, sizeof(int)))
740 	goto out;
741     if (error = copyout(&lf->id, &stat->id, sizeof(int)))
742 	goto out;
743     if (error = copyout(&lf->address, &stat->address, sizeof(caddr_t)))
744 	goto out;
745     if (error = copyout(&lf->size, &stat->size, sizeof(size_t)))
746 	goto out;
747 
748     p->p_retval[0] = 0;
749 
750 out:
751     return error;
752 }
753 
754 int
755 kldfirstmod(struct proc* p, struct kldfirstmod_args* uap)
756 {
757     linker_file_t lf;
758     int error = 0;
759 
760     lf = linker_find_file_by_id(SCARG(uap, fileid));
761     if (lf) {
762 	if (TAILQ_FIRST(&lf->modules))
763 	    p->p_retval[0] = module_getid(TAILQ_FIRST(&lf->modules));
764 	else
765 	    p->p_retval[0] = 0;
766     } else
767 	error = ENOENT;
768 
769     return error;
770 }
771 
772 /*
773  * Preloaded module support
774  */
775 
776 static void
777 linker_preload(void* arg)
778 {
779     caddr_t		modptr;
780     char		*modname;
781     char		*modtype;
782     linker_file_t	lf;
783     linker_class_t	lc;
784     int			error;
785     struct linker_set	*sysinits;
786     struct sysinit	**sipp;
787     moduledata_t	*moddata;
788 
789     modptr = NULL;
790     while ((modptr = preload_search_next_name(modptr)) != NULL) {
791 	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
792 	modtype = (char *)preload_search_info(modptr, MODINFO_TYPE);
793 	if (modname == NULL) {
794 	    printf("Preloaded module at %p does not have a name!\n", modptr);
795 	    continue;
796 	}
797 	if (modtype == NULL) {
798 	    printf("Preloaded module at %p does not have a type!\n", modptr);
799 	    continue;
800 	}
801 	printf("Preloaded %s \"%s\" at %p.\n", modtype, modname, modptr);
802 	lf = linker_find_file_by_name(modname);
803 	if (lf) {
804 	    lf->userrefs++;
805 	    continue;
806 	}
807 	lf = NULL;
808 	for (lc = TAILQ_FIRST(&classes); lc; lc = TAILQ_NEXT(lc, link)) {
809 	    error = lc->ops->load_file(modname, &lf);
810 	    if (error) {
811 		lf = NULL;
812 		break;
813 	    }
814 	}
815 	if (lf) {
816 	    lf->userrefs++;
817 
818 	    sysinits = (struct linker_set*)
819 		linker_file_lookup_symbol(lf, "sysinit_set", 0);
820 	    if (sysinits) {
821 		/* HACK ALERT!
822 		 * This is to set the sysinit moduledata so that the module
823 		 * can attach itself to the correct containing file.
824 		 * The sysinit could be run at *any* time.
825 		 */
826 		for (sipp = (struct sysinit **)sysinits->ls_items; *sipp; sipp++) {
827 		    if ((*sipp)->func == module_register_init) {
828 			moddata = (*sipp)->udata;
829 			moddata->_file = lf;
830 		    }
831 		}
832 		sysinit_add((struct sysinit **)sysinits->ls_items);
833 	    }
834 	}
835     }
836 }
837 
838 SYSINIT(preload, SI_SUB_KLD, SI_ORDER_MIDDLE, linker_preload, 0);
839 
840 /*
841  * Search for a not-loaded module by name.
842  *
843  * Modules may be found in the following locations:
844  *
845  * - preloaded (result is just the module name)
846  * - on disk (result is full path to module)
847  *
848  * If the module name is qualified in any way (contains path, etc.)
849  * the we simply return a copy of it.
850  *
851  * The search path can be manipulated via sysctl.  Note that we use the ';'
852  * character as a separator to be consistent with the bootloader.
853  */
854 
855 static char linker_path[MAXPATHLEN + 1] = "/;/boot/;/modules/";
856 
857 SYSCTL_STRING(_kern, OID_AUTO, module_path, CTLFLAG_RW, linker_path,
858 	      sizeof(linker_path), "module load search path");
859 
860 static char *
861 linker_strdup(const char *str)
862 {
863     char	*result;
864 
865     if ((result = malloc((strlen(str) + 1), M_LINKER, M_WAITOK)) != NULL)
866 	strcpy(result, str);
867     return(result);
868 }
869 
870 char *
871 linker_search_path(const char *name)
872 {
873     struct nameidata	nd;
874     struct proc		*p = curproc;	/* XXX */
875     char		*cp, *ep, *result;
876     int			error;
877     enum vtype		type;
878 
879     /* qualified at all? */
880     if (index(name, '/'))
881 	return(linker_strdup(name));
882 
883     /* traverse the linker path */
884     cp = linker_path;
885     for (;;) {
886 
887 	/* find the end of this component */
888 	for (ep = cp; (*ep != 0) && (*ep != ';'); ep++)
889 	    ;
890 	result = malloc((strlen(name) + (ep - cp) + 1), M_LINKER, M_WAITOK);
891 	if (result == NULL)	/* actually ENOMEM */
892 	    return(NULL);
893 
894 	strncpy(result, cp, ep - cp);
895 	strcpy(result + (ep - cp), name);
896 
897 	/*
898 	 * Attempt to open the file, and return the path if we succeed and it's
899 	 * a regular file.
900 	 */
901 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, result, p);
902 	error = vn_open(&nd, FREAD, 0);
903 	if (error == 0) {
904 	    type = nd.ni_vp->v_type;
905 	    VOP_UNLOCK(nd.ni_vp, 0, p);
906 	    vn_close(nd.ni_vp, FREAD, p->p_ucred, p);
907 	    if (type == VREG)
908 		return(result);
909 	}
910 	free(result, M_LINKER);
911 
912 	if (*ep == 0)
913 	    break;
914 	cp = ep + 1;
915     }
916     return(NULL);
917 }
918