xref: /freebsd/stand/libsa/cd9660.c (revision 8b959dd6a3921c35395bef4a6d7ad2426a3bd88e)
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 __FBSDID("$FreeBSD$");
36 
37 /*
38  * Stand-alone ISO9660 file reading package.
39  *
40  * Note: This doesn't support Rock Ridge extensions, extended attributes,
41  * blocksizes other than 2048 bytes, multi-extent files, etc.
42  */
43 #include <sys/param.h>
44 #include <string.h>
45 #include <stdbool.h>
46 #include <sys/dirent.h>
47 #include <fs/cd9660/iso.h>
48 #include <fs/cd9660/cd9660_rrip.h>
49 
50 #include "stand.h"
51 
52 #define	SUSP_CONTINUATION	"CE"
53 #define	SUSP_PRESENT		"SP"
54 #define	SUSP_STOP		"ST"
55 #define	SUSP_EXTREF		"ER"
56 #define	RRIP_NAME		"NM"
57 
58 typedef struct {
59 	ISO_SUSP_HEADER		h;
60 	u_char signature	[ISODCL (  5,    6)];
61 	u_char len_skp		[ISODCL (  7,    7)]; /* 711 */
62 } ISO_SUSP_PRESENT;
63 
64 static int	buf_read_file(struct open_file *f, char **buf_p,
65 		    size_t *size_p);
66 static int	cd9660_open(const char *path, struct open_file *f);
67 static int	cd9660_close(struct open_file *f);
68 static int	cd9660_read(struct open_file *f, void *buf, size_t size,
69 		    size_t *resid);
70 static off_t	cd9660_seek(struct open_file *f, off_t offset, int where);
71 static int	cd9660_stat(struct open_file *f, struct stat *sb);
72 static int	cd9660_readdir(struct open_file *f, struct dirent *d);
73 static int	cd9660_mount(const char *, const char *, void **);
74 static int	cd9660_unmount(const char *, void *);
75 static int	dirmatch(struct open_file *f, const char *path,
76 		    struct iso_directory_record *dp, int use_rrip, int lenskip);
77 static int	rrip_check(struct open_file *f, struct iso_directory_record *dp,
78 		    int *lenskip);
79 static char	*rrip_lookup_name(struct open_file *f,
80 		    struct iso_directory_record *dp, int lenskip, size_t *len);
81 static ISO_SUSP_HEADER *susp_lookup_record(struct open_file *f,
82 		    const char *identifier, struct iso_directory_record *dp,
83 		    int lenskip);
84 
85 struct fs_ops cd9660_fsops = {
86 	.fs_name = "cd9660",
87 	.fo_open = cd9660_open,
88 	.fo_close = cd9660_close,
89 	.fo_read = cd9660_read,
90 	.fo_write = null_write,
91 	.fo_seek = cd9660_seek,
92 	.fo_stat = cd9660_stat,
93 	.fo_readdir = cd9660_readdir,
94 	.fo_mount = cd9660_mount,
95 	.fo_unmount = cd9660_unmount
96 };
97 
98 typedef struct cd9660_mnt {
99 	struct devdesc			*cd_dev;
100 	int				cd_fd;
101 	struct iso_directory_record	cd_rec;
102 	STAILQ_ENTRY(cd9660_mnt)	cd_link;
103 } cd9660_mnt_t;
104 
105 typedef STAILQ_HEAD(cd9660_mnt_list, cd9660_mnt) cd9660_mnt_list_t;
106 static cd9660_mnt_list_t mnt_list = STAILQ_HEAD_INITIALIZER(mnt_list);
107 
108 #define	F_ISDIR		0x0001		/* Directory */
109 #define	F_ROOTDIR	0x0002		/* Root directory */
110 #define	F_RR		0x0004		/* Rock Ridge on this volume */
111 
112 struct file {
113 	int 		f_flags;	/* file flags */
114 	off_t 		f_off;		/* Current offset within file */
115 	daddr_t 	f_bno;		/* Starting block number */
116 	off_t 		f_size;		/* Size of file */
117 	daddr_t		f_buf_blkno;	/* block number of data block */
118 	char		*f_buf;		/* buffer for data block */
119 	int		f_susp_skip;	/* len_skip for SUSP records */
120 };
121 
122 struct ptable_ent {
123 	char namlen	[ISODCL( 1, 1)];	/* 711 */
124 	char extlen	[ISODCL( 2, 2)];	/* 711 */
125 	char block	[ISODCL( 3, 6)];	/* 732 */
126 	char parent	[ISODCL( 7, 8)];	/* 722 */
127 	char name	[1];
128 };
129 #define	PTFIXSZ		8
130 #define	PTSIZE(pp)	roundup(PTFIXSZ + isonum_711((pp)->namlen), 2)
131 
132 #define	cdb2devb(bno)	((bno) * ISO_DEFAULT_BLOCK_SIZE / DEV_BSIZE)
133 
134 static ISO_SUSP_HEADER *
135 susp_lookup_record(struct open_file *f, const char *identifier,
136     struct iso_directory_record *dp, int lenskip)
137 {
138 	static char susp_buffer[ISO_DEFAULT_BLOCK_SIZE];
139 	ISO_SUSP_HEADER *sh;
140 	ISO_RRIP_CONT *shc;
141 	char *p, *end;
142 	int error;
143 	size_t read;
144 
145 	p = dp->name + isonum_711(dp->name_len) + lenskip;
146 	/* Names of even length have a padding byte after the name. */
147 	if ((isonum_711(dp->name_len) & 1) == 0)
148 		p++;
149 	end = (char *)dp + isonum_711(dp->length);
150 	while (p + 3 < end) {
151 		sh = (ISO_SUSP_HEADER *)p;
152 		if (bcmp(sh->type, identifier, 2) == 0)
153 			return (sh);
154 		if (bcmp(sh->type, SUSP_STOP, 2) == 0)
155 			return (NULL);
156 		if (bcmp(sh->type, SUSP_CONTINUATION, 2) == 0) {
157 			shc = (ISO_RRIP_CONT *)sh;
158 			error = f->f_dev->dv_strategy(f->f_devdata, F_READ,
159 			    cdb2devb(isonum_733(shc->location)),
160 			    ISO_DEFAULT_BLOCK_SIZE, susp_buffer, &read);
161 
162 			/* Bail if it fails. */
163 			if (error != 0 || read != ISO_DEFAULT_BLOCK_SIZE)
164 				return (NULL);
165 			p = susp_buffer + isonum_733(shc->offset);
166 			end = p + isonum_733(shc->length);
167 		} else {
168 			/* Ignore this record and skip to the next. */
169 			p += isonum_711(sh->length);
170 
171 			/* Avoid infinite loops with corrupted file systems */
172 			if (isonum_711(sh->length) == 0)
173 				return (NULL);
174 		}
175 	}
176 	return (NULL);
177 }
178 
179 static char *
180 rrip_lookup_name(struct open_file *f, struct iso_directory_record *dp,
181     int lenskip, size_t *len)
182 {
183 	ISO_RRIP_ALTNAME *p;
184 
185 	if (len == NULL)
186 		return (NULL);
187 
188 	p = (ISO_RRIP_ALTNAME *)susp_lookup_record(f, RRIP_NAME, dp, lenskip);
189 	if (p == NULL)
190 		return (NULL);
191 	switch (*p->flags) {
192 	case ISO_SUSP_CFLAG_CURRENT:
193 		*len = 1;
194 		return (".");
195 	case ISO_SUSP_CFLAG_PARENT:
196 		*len = 2;
197 		return ("..");
198 	case 0:
199 		*len = isonum_711(p->h.length) - 5;
200 		return ((char *)p + 5);
201 	default:
202 		/*
203 		 * We don't handle hostnames or continued names as they are
204 		 * too hard, so just bail and use the default name.
205 		 */
206 		return (NULL);
207 	}
208 }
209 
210 static int
211 rrip_check(struct open_file *f, struct iso_directory_record *dp, int *lenskip)
212 {
213 	ISO_SUSP_PRESENT *sp;
214 	ISO_RRIP_EXTREF *er;
215 	char *p;
216 
217 	/* First, see if we can find a SP field. */
218 	p = dp->name + isonum_711(dp->name_len);
219 	if (p > (char *)dp + isonum_711(dp->length))
220 		return (0);
221 	sp = (ISO_SUSP_PRESENT *)p;
222 	if (bcmp(sp->h.type, SUSP_PRESENT, 2) != 0)
223 		return (0);
224 	if (isonum_711(sp->h.length) != sizeof(ISO_SUSP_PRESENT))
225 		return (0);
226 	if (sp->signature[0] != 0xbe || sp->signature[1] != 0xef)
227 		return (0);
228 	*lenskip = isonum_711(sp->len_skp);
229 
230 	/*
231 	 * Now look for an ER field.  If RRIP is present, then there must
232 	 * be at least one of these.  It would be more pedantic to walk
233 	 * through the list of fields looking for a Rock Ridge ER field.
234 	 */
235 	er = (ISO_RRIP_EXTREF *)susp_lookup_record(f, SUSP_EXTREF, dp, 0);
236 	if (er == NULL)
237 		return (0);
238 	return (1);
239 }
240 
241 static int
242 dirmatch(struct open_file *f, const char *path, struct iso_directory_record *dp,
243     int use_rrip, int lenskip)
244 {
245 	size_t len, plen;
246 	char *cp, *sep;
247 	int i, icase;
248 
249 	if (use_rrip)
250 		cp = rrip_lookup_name(f, dp, lenskip, &len);
251 	else
252 		cp = NULL;
253 	if (cp == NULL) {
254 		len = isonum_711(dp->name_len);
255 		cp = dp->name;
256 		icase = 1;
257 	} else
258 		icase = 0;
259 
260 	sep = strchr(path, '/');
261 	if (sep != NULL) {
262 		plen = sep - path;
263 	} else {
264 		plen = strlen(path);
265 	}
266 
267 	if (plen != len)
268 		return (0);
269 
270 	for (i = len; --i >= 0; path++, cp++) {
271 		if (!*path || *path == '/')
272 			break;
273 		if (*path == *cp)
274 			continue;
275 		if (!icase && toupper(*path) == *cp)
276 			continue;
277 		return 0;
278 	}
279 	if (*path && *path != '/')
280 		return 0;
281 	/*
282 	 * Allow stripping of trailing dots and the version number.
283 	 * Note that this will find the first instead of the last version
284 	 * of a file.
285 	 */
286 	if (i >= 0 && (*cp == ';' || *cp == '.')) {
287 		/* This is to prevent matching of numeric extensions */
288 		if (*cp == '.' && cp[1] != ';')
289 			return 0;
290 		while (--i >= 0)
291 			if (*++cp != ';' && (*cp < '0' || *cp > '9'))
292 				return 0;
293 	}
294 	return 1;
295 }
296 
297 static int
298 cd9660_read_dr(struct open_file *f, struct iso_directory_record *rec)
299 {
300 	struct iso_primary_descriptor *vd;
301 	size_t read;
302 	daddr_t bno;
303 	int rc;
304 
305 	errno = 0;
306 	vd = malloc(MAX(ISO_DEFAULT_BLOCK_SIZE,
307 	    sizeof(struct iso_primary_descriptor)));
308 	if (vd == NULL)
309 		return (errno);
310 
311 	for (bno = 16;; bno++) {
312 		twiddle(1);
313 		rc = f->f_dev->dv_strategy(f->f_devdata, F_READ, cdb2devb(bno),
314 		    ISO_DEFAULT_BLOCK_SIZE, (char *)vd, &read);
315 		if (rc)
316 			goto out;
317 		if (read != ISO_DEFAULT_BLOCK_SIZE) {
318 			rc = EIO;
319 			goto out;
320 		}
321 		rc = EINVAL;
322 		if (bcmp(vd->id, ISO_STANDARD_ID, sizeof(vd->id)) != 0)
323 			goto out;
324 		if (isonum_711(vd->type) == ISO_VD_END)
325 			goto out;
326 		if (isonum_711(vd->type) == ISO_VD_PRIMARY)
327 			break;
328 	}
329 	if (isonum_723(vd->logical_block_size) == ISO_DEFAULT_BLOCK_SIZE) {
330 		bcopy(vd->root_directory_record, rec, sizeof(*rec));
331 		rc = 0;
332 	}
333 out:
334 	free(vd);
335 	return (rc);
336 }
337 
338 static int
339 cd9660_open(const char *path, struct open_file *f)
340 {
341 	struct file *fp = NULL;
342 	void *buf;
343 	size_t read, dsize, off;
344 	daddr_t bno, boff;
345 	struct iso_directory_record rec;
346 	struct iso_directory_record *dp = NULL;
347 	int rc, first, use_rrip, lenskip;
348 	bool isdir = false;
349 	struct devdesc *dev;
350 	cd9660_mnt_t *mnt;
351 
352 	/* First find the volume descriptor */
353 	errno = 0;
354 	buf = malloc(MAX(ISO_DEFAULT_BLOCK_SIZE,
355 	    sizeof(struct iso_primary_descriptor)));
356 	if (buf == NULL)
357 		return (errno);
358 
359 	dev = f->f_devdata;
360 	STAILQ_FOREACH(mnt, &mnt_list, cd_link) {
361 		if (dev->d_dev->dv_type == mnt->cd_dev->d_dev->dv_type &&
362 		    dev->d_unit == mnt->cd_dev->d_unit)
363 			break;
364 	}
365 
366 	rc = 0;
367 	if (mnt == NULL)
368 		rc = cd9660_read_dr(f, &rec);
369 	else
370 		rec = mnt->cd_rec;
371 
372 	if (rc != 0)
373 		goto out;
374 
375 	if (*path == '/')
376 		path++; /* eat leading '/' */
377 
378 	first = 1;
379 	use_rrip = 0;
380 	lenskip = 0;
381 	while (*path) {
382 		bno = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
383 		dsize = isonum_733(rec.size);
384 		off = 0;
385 		boff = 0;
386 
387 		while (off < dsize) {
388 			if ((off % ISO_DEFAULT_BLOCK_SIZE) == 0) {
389 				twiddle(1);
390 				rc = f->f_dev->dv_strategy
391 					(f->f_devdata, F_READ,
392 					 cdb2devb(bno + boff),
393 					 ISO_DEFAULT_BLOCK_SIZE,
394 					 buf, &read);
395 				if (rc)
396 					goto out;
397 				if (read != ISO_DEFAULT_BLOCK_SIZE) {
398 					rc = EIO;
399 					goto out;
400 				}
401 				boff++;
402 				dp = (struct iso_directory_record *) buf;
403 			}
404 			if (isonum_711(dp->length) == 0) {
405 			    /* skip to next block, if any */
406 			    off = boff * ISO_DEFAULT_BLOCK_SIZE;
407 			    continue;
408 			}
409 
410 			/* See if RRIP is in use. */
411 			if (first)
412 				use_rrip = rrip_check(f, dp, &lenskip);
413 
414 			if (dirmatch(f, path, dp, use_rrip,
415 			    first ? 0 : lenskip)) {
416 				first = 0;
417 				break;
418 			} else
419 				first = 0;
420 
421 			dp = (struct iso_directory_record *)
422 				((char *) dp + isonum_711(dp->length));
423 			/* If the new block has zero length, it is padding. */
424 			if (isonum_711(dp->length) == 0) {
425 				/* Skip to next block, if any. */
426 				off = boff * ISO_DEFAULT_BLOCK_SIZE;
427 				continue;
428 			}
429 			off += isonum_711(dp->length);
430 		}
431 		if (off >= dsize) {
432 			rc = ENOENT;
433 			goto out;
434 		}
435 
436 		rec = *dp;
437 		while (*path && *path != '/') /* look for next component */
438 			path++;
439 
440 		if (*path)	/* this component was directory */
441 			isdir = true;
442 
443 		while (*path == '/')
444 			path++;	/* skip '/' */
445 
446 		if (*path)	/* We do have next component. */
447 			isdir = false;
448 	}
449 
450 	/*
451 	 * if the path had trailing / but the path does point to file,
452 	 * report the error ENOTDIR.
453 	 */
454 	if (isdir == true && (isonum_711(rec.flags) & 2) == 0) {
455 		rc = ENOTDIR;
456 		goto out;
457 	}
458 
459 	/* allocate file system specific data structure */
460 	fp = malloc(sizeof(struct file));
461 	bzero(fp, sizeof(struct file));
462 	f->f_fsdata = (void *)fp;
463 
464 	if ((isonum_711(rec.flags) & 2) != 0) {
465 		fp->f_flags = F_ISDIR;
466 	}
467 	if (first) {
468 		fp->f_flags |= F_ROOTDIR;
469 
470 		/* Check for Rock Ridge since we didn't in the loop above. */
471 		bno = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
472 		twiddle(1);
473 		rc = f->f_dev->dv_strategy(f->f_devdata, F_READ, cdb2devb(bno),
474 		    ISO_DEFAULT_BLOCK_SIZE, buf, &read);
475 		if (rc)
476 			goto out;
477 		if (read != ISO_DEFAULT_BLOCK_SIZE) {
478 			rc = EIO;
479 			goto out;
480 		}
481 		dp = (struct iso_directory_record *)buf;
482 		use_rrip = rrip_check(f, dp, &lenskip);
483 	}
484 	if (use_rrip) {
485 		fp->f_flags |= F_RR;
486 		fp->f_susp_skip = lenskip;
487 	}
488 	fp->f_off = 0;
489 	fp->f_bno = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
490 	fp->f_size = isonum_733(rec.size);
491 	free(buf);
492 
493 	return 0;
494 
495 out:
496 	free(fp);
497 	free(buf);
498 
499 	return rc;
500 }
501 
502 static int
503 cd9660_close(struct open_file *f)
504 {
505 	struct file *fp = (struct file *)f->f_fsdata;
506 
507 	f->f_fsdata = NULL;
508 	free(fp);
509 
510 	return 0;
511 }
512 
513 static int
514 buf_read_file(struct open_file *f, char **buf_p, size_t *size_p)
515 {
516 	struct file *fp = (struct file *)f->f_fsdata;
517 	daddr_t blkno, blkoff;
518 	int rc = 0;
519 	size_t read;
520 
521 	blkno = fp->f_off / ISO_DEFAULT_BLOCK_SIZE + fp->f_bno;
522 	blkoff = fp->f_off % ISO_DEFAULT_BLOCK_SIZE;
523 
524 	if (blkno != fp->f_buf_blkno) {
525 		if (fp->f_buf == (char *)0)
526 			fp->f_buf = malloc(ISO_DEFAULT_BLOCK_SIZE);
527 
528 		twiddle(16);
529 		rc = f->f_dev->dv_strategy(f->f_devdata, F_READ,
530 		    cdb2devb(blkno), ISO_DEFAULT_BLOCK_SIZE,
531 		    fp->f_buf, &read);
532 		if (rc)
533 			return (rc);
534 		if (read != ISO_DEFAULT_BLOCK_SIZE)
535 			return (EIO);
536 
537 		fp->f_buf_blkno = blkno;
538 	}
539 
540 	*buf_p = fp->f_buf + blkoff;
541 	*size_p = ISO_DEFAULT_BLOCK_SIZE - blkoff;
542 
543 	if (*size_p > fp->f_size - fp->f_off)
544 		*size_p = fp->f_size - fp->f_off;
545 	return (rc);
546 }
547 
548 static int
549 cd9660_read(struct open_file *f, void *start, size_t size, size_t *resid)
550 {
551 	struct file *fp = (struct file *)f->f_fsdata;
552 	char *buf, *addr;
553 	size_t buf_size, csize;
554 	int rc = 0;
555 
556 	addr = start;
557 	while (size) {
558 		if (fp->f_off < 0 || fp->f_off >= fp->f_size)
559 			break;
560 
561 		rc = buf_read_file(f, &buf, &buf_size);
562 		if (rc)
563 			break;
564 
565 		csize = size > buf_size ? buf_size : size;
566 		bcopy(buf, addr, csize);
567 
568 		fp->f_off += csize;
569 		addr += csize;
570 		size -= csize;
571 	}
572 	if (resid)
573 		*resid = size;
574 	return (rc);
575 }
576 
577 static int
578 cd9660_readdir(struct open_file *f, struct dirent *d)
579 {
580 	struct file *fp = (struct file *)f->f_fsdata;
581 	struct iso_directory_record *ep;
582 	size_t buf_size, reclen, namelen;
583 	int error = 0;
584 	int lenskip;
585 	char *buf, *name;
586 
587 again:
588 	if (fp->f_off >= fp->f_size)
589 		return (ENOENT);
590 	error = buf_read_file(f, &buf, &buf_size);
591 	if (error)
592 		return (error);
593 	ep = (struct iso_directory_record *)buf;
594 
595 	if (isonum_711(ep->length) == 0) {
596 		daddr_t blkno;
597 
598 		/* skip to next block, if any */
599 		blkno = fp->f_off / ISO_DEFAULT_BLOCK_SIZE;
600 		fp->f_off = (blkno + 1) * ISO_DEFAULT_BLOCK_SIZE;
601 		goto again;
602 	}
603 
604 	if (fp->f_flags & F_RR) {
605 		if (fp->f_flags & F_ROOTDIR && fp->f_off == 0)
606 			lenskip = 0;
607 		else
608 			lenskip = fp->f_susp_skip;
609 		name = rrip_lookup_name(f, ep, lenskip, &namelen);
610 	} else
611 		name = NULL;
612 	if (name == NULL) {
613 		namelen = isonum_711(ep->name_len);
614 		name = ep->name;
615 		if (namelen == 1) {
616 			if (ep->name[0] == 0)
617 				name = ".";
618 			else if (ep->name[0] == 1) {
619 				namelen = 2;
620 				name = "..";
621 			}
622 		}
623 	}
624 	reclen = sizeof(struct dirent) - (MAXNAMLEN+1) + namelen + 1;
625 	reclen = (reclen + 3) & ~3;
626 
627 	d->d_fileno = isonum_733(ep->extent);
628 	d->d_reclen = reclen;
629 	if (isonum_711(ep->flags) & 2)
630 		d->d_type = DT_DIR;
631 	else
632 		d->d_type = DT_REG;
633 	d->d_namlen = namelen;
634 
635 	bcopy(name, d->d_name, d->d_namlen);
636 	d->d_name[d->d_namlen] = 0;
637 
638 	fp->f_off += isonum_711(ep->length);
639 	return (0);
640 }
641 
642 static off_t
643 cd9660_seek(struct open_file *f, off_t offset, int where)
644 {
645 	struct file *fp = (struct file *)f->f_fsdata;
646 
647 	switch (where) {
648 	case SEEK_SET:
649 		fp->f_off = offset;
650 		break;
651 	case SEEK_CUR:
652 		fp->f_off += offset;
653 		break;
654 	case SEEK_END:
655 		fp->f_off = fp->f_size - offset;
656 		break;
657 	default:
658 		return -1;
659 	}
660 	return fp->f_off;
661 }
662 
663 static int
664 cd9660_stat(struct open_file *f, struct stat *sb)
665 {
666 	struct file *fp = (struct file *)f->f_fsdata;
667 
668 	/* only important stuff */
669 	sb->st_mode = S_IRUSR | S_IRGRP | S_IROTH;
670 	if (fp->f_flags & F_ISDIR)
671 		sb->st_mode |= S_IFDIR;
672 	else
673 		sb->st_mode |= S_IFREG;
674 	sb->st_uid = sb->st_gid = 0;
675 	sb->st_size = fp->f_size;
676 	return 0;
677 }
678 
679 static int
680 cd9660_mount(const char *dev, const char *path, void **data)
681 {
682 	cd9660_mnt_t *mnt;
683 	struct open_file *f;
684 	char *fs;
685 
686 	errno = 0;
687 	mnt = calloc(1, sizeof(*mnt));
688 	if (mnt == NULL)
689 		return (errno);
690 	mnt->cd_fd = -1;
691 
692 	if (asprintf(&fs, "%s%s", dev, path) < 0)
693 		goto done;
694 
695 	mnt->cd_fd = open(fs, O_RDONLY);
696 	free(fs);
697 	if (mnt->cd_fd == -1)
698 		goto done;
699 
700 	f = fd2open_file(mnt->cd_fd);
701 	/* Is it cd9660 file system? */
702 	if (strcmp(f->f_ops->fs_name, "cd9660") == 0) {
703 		mnt->cd_dev = f->f_devdata;
704 		errno = cd9660_read_dr(f, &mnt->cd_rec);
705 		STAILQ_INSERT_TAIL(&mnt_list, mnt, cd_link);
706 	} else {
707 		errno = ENXIO;
708 	}
709 
710 done:
711 	if (errno != 0) {
712 		free(mnt->cd_dev);
713 		if (mnt->cd_fd >= 0)
714 			close(mnt->cd_fd);
715 		free(mnt);
716 	} else {
717 		*data = mnt;
718 	}
719 	return (errno);
720 }
721 
722 static int
723 cd9660_unmount(const char *dev __unused, void *data)
724 {
725 	cd9660_mnt_t *mnt = data;
726 
727 	STAILQ_REMOVE(&mnt_list, mnt, cd9660_mnt, cd_link);
728 	close(mnt->cd_fd);
729 	free(mnt);
730 	return (0);
731 }
732