xref: /freebsd/stand/libsa/cd9660.c (revision e0c4386e7e71d93b0edc0c8fa156263fc4a8b0b6)
1 /*	$NetBSD: cd9660.c,v 1.5 1997/06/26 19:11:33 drochner Exp $	*/
2 
3 /*
4  * Copyright (C) 1996 Wolfgang Solfrank.
5  * Copyright (C) 1996 TooLs GmbH.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by TooLs GmbH.
19  * 4. The name of TooLs GmbH may not be used to endorse or promote products
20  *    derived from this software without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
27  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
28  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
31  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 /*
36  * Stand-alone ISO9660 file reading package.
37  *
38  * Note: This doesn't support Rock Ridge extensions, extended attributes,
39  * blocksizes other than 2048 bytes, multi-extent files, etc.
40  */
41 #include <sys/param.h>
42 #include <string.h>
43 #include <stdbool.h>
44 #include <sys/dirent.h>
45 #include <fs/cd9660/iso.h>
46 #include <fs/cd9660/cd9660_rrip.h>
47 
48 #include "stand.h"
49 
50 #define	SUSP_CONTINUATION	"CE"
51 #define	SUSP_PRESENT		"SP"
52 #define	SUSP_STOP		"ST"
53 #define	SUSP_EXTREF		"ER"
54 #define	RRIP_NAME		"NM"
55 
56 typedef struct {
57 	ISO_SUSP_HEADER		h;
58 	u_char signature	[ISODCL (  5,    6)];
59 	u_char len_skp		[ISODCL (  7,    7)]; /* 711 */
60 } ISO_SUSP_PRESENT;
61 
62 static int	buf_read_file(struct open_file *f, char **buf_p,
63 		    size_t *size_p);
64 static int	cd9660_open(const char *path, struct open_file *f);
65 static int	cd9660_close(struct open_file *f);
66 static int	cd9660_read(struct open_file *f, void *buf, size_t size,
67 		    size_t *resid);
68 static off_t	cd9660_seek(struct open_file *f, off_t offset, int where);
69 static int	cd9660_stat(struct open_file *f, struct stat *sb);
70 static int	cd9660_readdir(struct open_file *f, struct dirent *d);
71 static int	cd9660_mount(const char *, const char *, void **);
72 static int	cd9660_unmount(const char *, void *);
73 static int	dirmatch(struct open_file *f, const char *path,
74 		    struct iso_directory_record *dp, int use_rrip, int lenskip);
75 static int	rrip_check(struct open_file *f, struct iso_directory_record *dp,
76 		    int *lenskip);
77 static char	*rrip_lookup_name(struct open_file *f,
78 		    struct iso_directory_record *dp, int lenskip, size_t *len);
79 static ISO_SUSP_HEADER *susp_lookup_record(struct open_file *f,
80 		    const char *identifier, struct iso_directory_record *dp,
81 		    int lenskip);
82 
83 struct fs_ops cd9660_fsops = {
84 	.fs_name = "cd9660",
85 	.fo_open = cd9660_open,
86 	.fo_close = cd9660_close,
87 	.fo_read = cd9660_read,
88 	.fo_write = null_write,
89 	.fo_seek = cd9660_seek,
90 	.fo_stat = cd9660_stat,
91 	.fo_readdir = cd9660_readdir,
92 	.fo_mount = cd9660_mount,
93 	.fo_unmount = cd9660_unmount
94 };
95 
96 typedef struct cd9660_mnt {
97 	struct devdesc			*cd_dev;
98 	int				cd_fd;
99 	struct iso_directory_record	cd_rec;
100 	STAILQ_ENTRY(cd9660_mnt)	cd_link;
101 } cd9660_mnt_t;
102 
103 typedef STAILQ_HEAD(cd9660_mnt_list, cd9660_mnt) cd9660_mnt_list_t;
104 static cd9660_mnt_list_t mnt_list = STAILQ_HEAD_INITIALIZER(mnt_list);
105 
106 #define	F_ISDIR		0x0001		/* Directory */
107 #define	F_ROOTDIR	0x0002		/* Root directory */
108 #define	F_RR		0x0004		/* Rock Ridge on this volume */
109 
110 struct file {
111 	int 		f_flags;	/* file flags */
112 	off_t 		f_off;		/* Current offset within file */
113 	daddr_t 	f_bno;		/* Starting block number */
114 	off_t 		f_size;		/* Size of file */
115 	daddr_t		f_buf_blkno;	/* block number of data block */
116 	char		*f_buf;		/* buffer for data block */
117 	int		f_susp_skip;	/* len_skip for SUSP records */
118 };
119 
120 struct ptable_ent {
121 	char namlen	[ISODCL( 1, 1)];	/* 711 */
122 	char extlen	[ISODCL( 2, 2)];	/* 711 */
123 	char block	[ISODCL( 3, 6)];	/* 732 */
124 	char parent	[ISODCL( 7, 8)];	/* 722 */
125 	char name	[1];
126 };
127 #define	PTFIXSZ		8
128 #define	PTSIZE(pp)	roundup(PTFIXSZ + isonum_711((pp)->namlen), 2)
129 
130 #define	cdb2devb(bno)	((bno) * ISO_DEFAULT_BLOCK_SIZE / DEV_BSIZE)
131 
132 static ISO_SUSP_HEADER *
133 susp_lookup_record(struct open_file *f, const char *identifier,
134     struct iso_directory_record *dp, int lenskip)
135 {
136 	static char susp_buffer[ISO_DEFAULT_BLOCK_SIZE];
137 	ISO_SUSP_HEADER *sh;
138 	ISO_RRIP_CONT *shc;
139 	char *p, *end;
140 	int error;
141 	size_t read;
142 
143 	p = dp->name + isonum_711(dp->name_len) + lenskip;
144 	/* Names of even length have a padding byte after the name. */
145 	if ((isonum_711(dp->name_len) & 1) == 0)
146 		p++;
147 	end = (char *)dp + isonum_711(dp->length);
148 	while (p + 3 < end) {
149 		sh = (ISO_SUSP_HEADER *)p;
150 		if (bcmp(sh->type, identifier, 2) == 0)
151 			return (sh);
152 		if (bcmp(sh->type, SUSP_STOP, 2) == 0)
153 			return (NULL);
154 		if (bcmp(sh->type, SUSP_CONTINUATION, 2) == 0) {
155 			shc = (ISO_RRIP_CONT *)sh;
156 			error = f->f_dev->dv_strategy(f->f_devdata, F_READ,
157 			    cdb2devb(isonum_733(shc->location)),
158 			    ISO_DEFAULT_BLOCK_SIZE, susp_buffer, &read);
159 
160 			/* Bail if it fails. */
161 			if (error != 0 || read != ISO_DEFAULT_BLOCK_SIZE)
162 				return (NULL);
163 			p = susp_buffer + isonum_733(shc->offset);
164 			end = p + isonum_733(shc->length);
165 		} else {
166 			/* Ignore this record and skip to the next. */
167 			p += isonum_711(sh->length);
168 
169 			/* Avoid infinite loops with corrupted file systems */
170 			if (isonum_711(sh->length) == 0)
171 				return (NULL);
172 		}
173 	}
174 	return (NULL);
175 }
176 
177 static char *
178 rrip_lookup_name(struct open_file *f, struct iso_directory_record *dp,
179     int lenskip, size_t *len)
180 {
181 	ISO_RRIP_ALTNAME *p;
182 
183 	if (len == NULL)
184 		return (NULL);
185 
186 	p = (ISO_RRIP_ALTNAME *)susp_lookup_record(f, RRIP_NAME, dp, lenskip);
187 	if (p == NULL)
188 		return (NULL);
189 	switch (*p->flags) {
190 	case ISO_SUSP_CFLAG_CURRENT:
191 		*len = 1;
192 		return (".");
193 	case ISO_SUSP_CFLAG_PARENT:
194 		*len = 2;
195 		return ("..");
196 	case 0:
197 		*len = isonum_711(p->h.length) - 5;
198 		return ((char *)p + 5);
199 	default:
200 		/*
201 		 * We don't handle hostnames or continued names as they are
202 		 * too hard, so just bail and use the default name.
203 		 */
204 		return (NULL);
205 	}
206 }
207 
208 static int
209 rrip_check(struct open_file *f, struct iso_directory_record *dp, int *lenskip)
210 {
211 	ISO_SUSP_PRESENT *sp;
212 	ISO_RRIP_EXTREF *er;
213 	char *p;
214 
215 	/* First, see if we can find a SP field. */
216 	p = dp->name + isonum_711(dp->name_len);
217 	if (p > (char *)dp + isonum_711(dp->length))
218 		return (0);
219 	sp = (ISO_SUSP_PRESENT *)p;
220 	if (bcmp(sp->h.type, SUSP_PRESENT, 2) != 0)
221 		return (0);
222 	if (isonum_711(sp->h.length) != sizeof(ISO_SUSP_PRESENT))
223 		return (0);
224 	if (sp->signature[0] != 0xbe || sp->signature[1] != 0xef)
225 		return (0);
226 	*lenskip = isonum_711(sp->len_skp);
227 
228 	/*
229 	 * Now look for an ER field.  If RRIP is present, then there must
230 	 * be at least one of these.  It would be more pedantic to walk
231 	 * through the list of fields looking for a Rock Ridge ER field.
232 	 */
233 	er = (ISO_RRIP_EXTREF *)susp_lookup_record(f, SUSP_EXTREF, dp, 0);
234 	if (er == NULL)
235 		return (0);
236 	return (1);
237 }
238 
239 static int
240 dirmatch(struct open_file *f, const char *path, struct iso_directory_record *dp,
241     int use_rrip, int lenskip)
242 {
243 	size_t len, plen;
244 	char *cp, *sep;
245 	int i, icase;
246 
247 	if (use_rrip)
248 		cp = rrip_lookup_name(f, dp, lenskip, &len);
249 	else
250 		cp = NULL;
251 	if (cp == NULL) {
252 		len = isonum_711(dp->name_len);
253 		cp = dp->name;
254 		icase = 1;
255 	} else
256 		icase = 0;
257 
258 	sep = strchr(path, '/');
259 	if (sep != NULL) {
260 		plen = sep - path;
261 	} else {
262 		plen = strlen(path);
263 	}
264 
265 	if (plen != len)
266 		return (0);
267 
268 	for (i = len; --i >= 0; path++, cp++) {
269 		if (!*path || *path == '/')
270 			break;
271 		if (*path == *cp)
272 			continue;
273 		if (!icase && toupper(*path) == *cp)
274 			continue;
275 		return 0;
276 	}
277 	if (*path && *path != '/')
278 		return 0;
279 	/*
280 	 * Allow stripping of trailing dots and the version number.
281 	 * Note that this will find the first instead of the last version
282 	 * of a file.
283 	 */
284 	if (i >= 0 && (*cp == ';' || *cp == '.')) {
285 		/* This is to prevent matching of numeric extensions */
286 		if (*cp == '.' && cp[1] != ';')
287 			return 0;
288 		while (--i >= 0)
289 			if (*++cp != ';' && (*cp < '0' || *cp > '9'))
290 				return 0;
291 	}
292 	return 1;
293 }
294 
295 static int
296 cd9660_read_dr(struct open_file *f, struct iso_directory_record *rec)
297 {
298 	struct iso_primary_descriptor *vd;
299 	size_t read;
300 	daddr_t bno;
301 	int rc;
302 
303 	errno = 0;
304 	vd = malloc(MAX(ISO_DEFAULT_BLOCK_SIZE,
305 	    sizeof(struct iso_primary_descriptor)));
306 	if (vd == NULL)
307 		return (errno);
308 
309 	for (bno = 16;; bno++) {
310 		twiddle(1);
311 		rc = f->f_dev->dv_strategy(f->f_devdata, F_READ, cdb2devb(bno),
312 		    ISO_DEFAULT_BLOCK_SIZE, (char *)vd, &read);
313 		if (rc)
314 			goto out;
315 		if (read != ISO_DEFAULT_BLOCK_SIZE) {
316 			rc = EIO;
317 			goto out;
318 		}
319 		rc = EINVAL;
320 		if (bcmp(vd->id, ISO_STANDARD_ID, sizeof(vd->id)) != 0)
321 			goto out;
322 		if (isonum_711(vd->type) == ISO_VD_END)
323 			goto out;
324 		if (isonum_711(vd->type) == ISO_VD_PRIMARY)
325 			break;
326 	}
327 	if (isonum_723(vd->logical_block_size) == ISO_DEFAULT_BLOCK_SIZE) {
328 		bcopy(vd->root_directory_record, rec, sizeof(*rec));
329 		rc = 0;
330 	}
331 out:
332 	free(vd);
333 	return (rc);
334 }
335 
336 static int
337 cd9660_open(const char *path, struct open_file *f)
338 {
339 	struct file *fp = NULL;
340 	void *buf;
341 	size_t read, dsize, off;
342 	daddr_t bno, boff;
343 	struct iso_directory_record rec;
344 	struct iso_directory_record *dp = NULL;
345 	int rc, first, use_rrip, lenskip;
346 	bool isdir = false;
347 	struct devdesc *dev;
348 	cd9660_mnt_t *mnt;
349 
350 	/* First find the volume descriptor */
351 	errno = 0;
352 	buf = malloc(MAX(ISO_DEFAULT_BLOCK_SIZE,
353 	    sizeof(struct iso_primary_descriptor)));
354 	if (buf == NULL)
355 		return (errno);
356 
357 	dev = f->f_devdata;
358 	STAILQ_FOREACH(mnt, &mnt_list, cd_link) {
359 		if (dev->d_dev->dv_type == mnt->cd_dev->d_dev->dv_type &&
360 		    dev->d_unit == mnt->cd_dev->d_unit)
361 			break;
362 	}
363 
364 	rc = 0;
365 	if (mnt == NULL)
366 		rc = cd9660_read_dr(f, &rec);
367 	else
368 		rec = mnt->cd_rec;
369 
370 	if (rc != 0)
371 		goto out;
372 
373 	if (*path == '/')
374 		path++; /* eat leading '/' */
375 
376 	first = 1;
377 	use_rrip = 0;
378 	lenskip = 0;
379 	while (*path) {
380 		bno = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
381 		dsize = isonum_733(rec.size);
382 		off = 0;
383 		boff = 0;
384 
385 		while (off < dsize) {
386 			if ((off % ISO_DEFAULT_BLOCK_SIZE) == 0) {
387 				twiddle(1);
388 				rc = f->f_dev->dv_strategy
389 					(f->f_devdata, F_READ,
390 					 cdb2devb(bno + boff),
391 					 ISO_DEFAULT_BLOCK_SIZE,
392 					 buf, &read);
393 				if (rc)
394 					goto out;
395 				if (read != ISO_DEFAULT_BLOCK_SIZE) {
396 					rc = EIO;
397 					goto out;
398 				}
399 				boff++;
400 				dp = (struct iso_directory_record *) buf;
401 			}
402 			if (isonum_711(dp->length) == 0) {
403 			    /* skip to next block, if any */
404 			    off = boff * ISO_DEFAULT_BLOCK_SIZE;
405 			    continue;
406 			}
407 
408 			/* See if RRIP is in use. */
409 			if (first)
410 				use_rrip = rrip_check(f, dp, &lenskip);
411 
412 			if (dirmatch(f, path, dp, use_rrip,
413 			    first ? 0 : lenskip)) {
414 				first = 0;
415 				break;
416 			} else
417 				first = 0;
418 
419 			dp = (struct iso_directory_record *)
420 				((char *) dp + isonum_711(dp->length));
421 			/* If the new block has zero length, it is padding. */
422 			if (isonum_711(dp->length) == 0) {
423 				/* Skip to next block, if any. */
424 				off = boff * ISO_DEFAULT_BLOCK_SIZE;
425 				continue;
426 			}
427 			off += isonum_711(dp->length);
428 		}
429 		if (off >= dsize) {
430 			rc = ENOENT;
431 			goto out;
432 		}
433 
434 		rec = *dp;
435 		while (*path && *path != '/') /* look for next component */
436 			path++;
437 
438 		if (*path)	/* this component was directory */
439 			isdir = true;
440 
441 		while (*path == '/')
442 			path++;	/* skip '/' */
443 
444 		if (*path)	/* We do have next component. */
445 			isdir = false;
446 	}
447 
448 	/*
449 	 * if the path had trailing / but the path does point to file,
450 	 * report the error ENOTDIR.
451 	 */
452 	if (isdir == true && (isonum_711(rec.flags) & 2) == 0) {
453 		rc = ENOTDIR;
454 		goto out;
455 	}
456 
457 	/* allocate file system specific data structure */
458 	fp = malloc(sizeof(struct file));
459 	bzero(fp, sizeof(struct file));
460 	f->f_fsdata = (void *)fp;
461 
462 	if ((isonum_711(rec.flags) & 2) != 0) {
463 		fp->f_flags = F_ISDIR;
464 	}
465 	if (first) {
466 		fp->f_flags |= F_ROOTDIR;
467 
468 		/* Check for Rock Ridge since we didn't in the loop above. */
469 		bno = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
470 		twiddle(1);
471 		rc = f->f_dev->dv_strategy(f->f_devdata, F_READ, cdb2devb(bno),
472 		    ISO_DEFAULT_BLOCK_SIZE, buf, &read);
473 		if (rc)
474 			goto out;
475 		if (read != ISO_DEFAULT_BLOCK_SIZE) {
476 			rc = EIO;
477 			goto out;
478 		}
479 		dp = (struct iso_directory_record *)buf;
480 		use_rrip = rrip_check(f, dp, &lenskip);
481 	}
482 	if (use_rrip) {
483 		fp->f_flags |= F_RR;
484 		fp->f_susp_skip = lenskip;
485 	}
486 	fp->f_off = 0;
487 	fp->f_bno = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
488 	fp->f_size = isonum_733(rec.size);
489 	free(buf);
490 
491 	return 0;
492 
493 out:
494 	free(fp);
495 	free(buf);
496 
497 	return rc;
498 }
499 
500 static int
501 cd9660_close(struct open_file *f)
502 {
503 	struct file *fp = (struct file *)f->f_fsdata;
504 
505 	f->f_fsdata = NULL;
506 	free(fp);
507 
508 	return 0;
509 }
510 
511 static int
512 buf_read_file(struct open_file *f, char **buf_p, size_t *size_p)
513 {
514 	struct file *fp = (struct file *)f->f_fsdata;
515 	daddr_t blkno, blkoff;
516 	int rc = 0;
517 	size_t read;
518 
519 	blkno = fp->f_off / ISO_DEFAULT_BLOCK_SIZE + fp->f_bno;
520 	blkoff = fp->f_off % ISO_DEFAULT_BLOCK_SIZE;
521 
522 	if (blkno != fp->f_buf_blkno) {
523 		if (fp->f_buf == (char *)0)
524 			fp->f_buf = malloc(ISO_DEFAULT_BLOCK_SIZE);
525 
526 		twiddle(16);
527 		rc = f->f_dev->dv_strategy(f->f_devdata, F_READ,
528 		    cdb2devb(blkno), ISO_DEFAULT_BLOCK_SIZE,
529 		    fp->f_buf, &read);
530 		if (rc)
531 			return (rc);
532 		if (read != ISO_DEFAULT_BLOCK_SIZE)
533 			return (EIO);
534 
535 		fp->f_buf_blkno = blkno;
536 	}
537 
538 	*buf_p = fp->f_buf + blkoff;
539 	*size_p = ISO_DEFAULT_BLOCK_SIZE - blkoff;
540 
541 	if (*size_p > fp->f_size - fp->f_off)
542 		*size_p = fp->f_size - fp->f_off;
543 	return (rc);
544 }
545 
546 static int
547 cd9660_read(struct open_file *f, void *start, size_t size, size_t *resid)
548 {
549 	struct file *fp = (struct file *)f->f_fsdata;
550 	char *buf, *addr;
551 	size_t buf_size, csize;
552 	int rc = 0;
553 
554 	addr = start;
555 	while (size) {
556 		if (fp->f_off < 0 || fp->f_off >= fp->f_size)
557 			break;
558 
559 		rc = buf_read_file(f, &buf, &buf_size);
560 		if (rc)
561 			break;
562 
563 		csize = size > buf_size ? buf_size : size;
564 		bcopy(buf, addr, csize);
565 
566 		fp->f_off += csize;
567 		addr += csize;
568 		size -= csize;
569 	}
570 	if (resid)
571 		*resid = size;
572 	return (rc);
573 }
574 
575 static int
576 cd9660_readdir(struct open_file *f, struct dirent *d)
577 {
578 	struct file *fp = (struct file *)f->f_fsdata;
579 	struct iso_directory_record *ep;
580 	size_t buf_size, reclen, namelen;
581 	int error = 0;
582 	int lenskip;
583 	char *buf, *name;
584 
585 again:
586 	if (fp->f_off >= fp->f_size)
587 		return (ENOENT);
588 	error = buf_read_file(f, &buf, &buf_size);
589 	if (error)
590 		return (error);
591 	ep = (struct iso_directory_record *)buf;
592 
593 	if (isonum_711(ep->length) == 0) {
594 		daddr_t blkno;
595 
596 		/* skip to next block, if any */
597 		blkno = fp->f_off / ISO_DEFAULT_BLOCK_SIZE;
598 		fp->f_off = (blkno + 1) * ISO_DEFAULT_BLOCK_SIZE;
599 		goto again;
600 	}
601 
602 	if (fp->f_flags & F_RR) {
603 		if (fp->f_flags & F_ROOTDIR && fp->f_off == 0)
604 			lenskip = 0;
605 		else
606 			lenskip = fp->f_susp_skip;
607 		name = rrip_lookup_name(f, ep, lenskip, &namelen);
608 	} else
609 		name = NULL;
610 	if (name == NULL) {
611 		namelen = isonum_711(ep->name_len);
612 		name = ep->name;
613 		if (namelen == 1) {
614 			if (ep->name[0] == 0)
615 				name = ".";
616 			else if (ep->name[0] == 1) {
617 				namelen = 2;
618 				name = "..";
619 			}
620 		}
621 	}
622 	reclen = sizeof(struct dirent) - (MAXNAMLEN+1) + namelen + 1;
623 	reclen = (reclen + 3) & ~3;
624 
625 	d->d_fileno = isonum_733(ep->extent);
626 	d->d_reclen = reclen;
627 	if (isonum_711(ep->flags) & 2)
628 		d->d_type = DT_DIR;
629 	else
630 		d->d_type = DT_REG;
631 	d->d_namlen = namelen;
632 
633 	bcopy(name, d->d_name, d->d_namlen);
634 	d->d_name[d->d_namlen] = 0;
635 
636 	fp->f_off += isonum_711(ep->length);
637 	return (0);
638 }
639 
640 static off_t
641 cd9660_seek(struct open_file *f, off_t offset, int where)
642 {
643 	struct file *fp = (struct file *)f->f_fsdata;
644 
645 	switch (where) {
646 	case SEEK_SET:
647 		fp->f_off = offset;
648 		break;
649 	case SEEK_CUR:
650 		fp->f_off += offset;
651 		break;
652 	case SEEK_END:
653 		fp->f_off = fp->f_size - offset;
654 		break;
655 	default:
656 		return -1;
657 	}
658 	return fp->f_off;
659 }
660 
661 static int
662 cd9660_stat(struct open_file *f, struct stat *sb)
663 {
664 	struct file *fp = (struct file *)f->f_fsdata;
665 
666 	/* only important stuff */
667 	sb->st_mode = S_IRUSR | S_IRGRP | S_IROTH;
668 	if (fp->f_flags & F_ISDIR)
669 		sb->st_mode |= S_IFDIR;
670 	else
671 		sb->st_mode |= S_IFREG;
672 	sb->st_uid = sb->st_gid = 0;
673 	sb->st_size = fp->f_size;
674 	return 0;
675 }
676 
677 static int
678 cd9660_mount(const char *dev, const char *path, void **data)
679 {
680 	cd9660_mnt_t *mnt;
681 	struct open_file *f;
682 	char *fs;
683 
684 	errno = 0;
685 	mnt = calloc(1, sizeof(*mnt));
686 	if (mnt == NULL)
687 		return (errno);
688 	mnt->cd_fd = -1;
689 
690 	if (asprintf(&fs, "%s%s", dev, path) < 0)
691 		goto done;
692 
693 	mnt->cd_fd = open(fs, O_RDONLY);
694 	free(fs);
695 	if (mnt->cd_fd == -1)
696 		goto done;
697 
698 	f = fd2open_file(mnt->cd_fd);
699 	/* Is it cd9660 file system? */
700 	if (strcmp(f->f_ops->fs_name, "cd9660") == 0) {
701 		mnt->cd_dev = f->f_devdata;
702 		errno = cd9660_read_dr(f, &mnt->cd_rec);
703 		STAILQ_INSERT_TAIL(&mnt_list, mnt, cd_link);
704 	} else {
705 		errno = ENXIO;
706 	}
707 
708 done:
709 	if (errno != 0) {
710 		free(mnt->cd_dev);
711 		if (mnt->cd_fd >= 0)
712 			close(mnt->cd_fd);
713 		free(mnt);
714 	} else {
715 		*data = mnt;
716 	}
717 	return (errno);
718 }
719 
720 static int
721 cd9660_unmount(const char *dev __unused, void *data)
722 {
723 	cd9660_mnt_t *mnt = data;
724 
725 	STAILQ_REMOVE(&mnt_list, mnt, cd9660_mnt, cd_link);
726 	close(mnt->cd_fd);
727 	free(mnt);
728 	return (0);
729 }
730