xref: /freebsd/stand/libsa/ufs.c (revision 5bb3134a8c21cb87b30e135ef168483f0333dabb)
1 /*	$NetBSD: ufs.c,v 1.20 1998/03/01 07:15:39 ross Exp $	*/
2 
3 /*-
4  * Copyright (c) 2002 Networks Associates Technology, Inc.
5  * All rights reserved.
6  *
7  * This software was developed for the FreeBSD Project by Marshall
8  * Kirk McKusick and Network Associates Laboratories, the Security
9  * Research Division of Network Associates, Inc. under DARPA/SPAWAR
10  * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS
11  * research program
12  *
13  * Copyright (c) 1982, 1989, 1993
14  *	The Regents of the University of California.  All rights reserved.
15  *
16  * This code is derived from software contributed to Berkeley by
17  * The Mach Operating System project at Carnegie-Mellon University.
18  *
19  * Redistribution and use in source and binary forms, with or without
20  * modification, are permitted provided that the following conditions
21  * are met:
22  * 1. Redistributions of source code must retain the above copyright
23  *    notice, this list of conditions and the following disclaimer.
24  * 2. Redistributions in binary form must reproduce the above copyright
25  *    notice, this list of conditions and the following disclaimer in the
26  *    documentation and/or other materials provided with the distribution.
27  * 3. Neither the name of the University nor the names of its contributors
28  *    may be used to endorse or promote products derived from this software
29  *    without specific prior written permission.
30  *
31  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
32  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
33  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
34  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
35  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
39  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
40  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
41  * SUCH DAMAGE.
42  *
43  *
44  * Copyright (c) 1990, 1991 Carnegie Mellon University
45  * All Rights Reserved.
46  *
47  * Author: David Golub
48  *
49  * Permission to use, copy, modify and distribute this software and its
50  * documentation is hereby granted, provided that both the copyright
51  * notice and this permission notice appear in all copies of the
52  * software, derivative works or modified versions, and any portions
53  * thereof, and that both notices appear in supporting documentation.
54  *
55  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
56  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
57  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
58  *
59  * Carnegie Mellon requests users of this software to return to
60  *
61  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
62  *  School of Computer Science
63  *  Carnegie Mellon University
64  *  Pittsburgh PA 15213-3890
65  *
66  * any improvements or extensions that they make and grant Carnegie the
67  * rights to redistribute these changes.
68  */
69 
70 #include <sys/cdefs.h>
71 __FBSDID("$FreeBSD$");
72 
73 /*
74  *	Stand-alone file reading package.
75  */
76 
77 #include <sys/param.h>
78 #include <sys/disklabel.h>
79 #include <sys/time.h>
80 #include <ufs/ufs/dinode.h>
81 #include <ufs/ufs/dir.h>
82 #include <ufs/ffs/fs.h>
83 #include "stand.h"
84 #include "disk.h"
85 #include "string.h"
86 
87 static int	ufs_open(const char *path, struct open_file *f);
88 static int	ufs_write(struct open_file *f, const void *buf, size_t size,
89 		size_t *resid);
90 static int	ufs_close(struct open_file *f);
91 static int	ufs_read(struct open_file *f, void *buf, size_t size, size_t *resid);
92 static off_t	ufs_seek(struct open_file *f, off_t offset, int where);
93 static int	ufs_stat(struct open_file *f, struct stat *sb);
94 static int	ufs_readdir(struct open_file *f, struct dirent *d);
95 static int	ufs_mount(const char *dev, const char *path, void **data);
96 static int	ufs_unmount(const char *dev, void *data);
97 
98 struct fs_ops ufs_fsops = {
99 	.fs_name = "ufs",
100 	.fo_open = ufs_open,
101 	.fo_close = ufs_close,
102 	.fo_read = ufs_read,
103 	.fo_write = ufs_write,
104 	.fo_seek = ufs_seek,
105 	.fo_stat = ufs_stat,
106 	.fo_readdir = ufs_readdir,
107 	.fo_mount = ufs_mount,
108 	.fo_unmount = ufs_unmount
109 };
110 
111 /*
112  * In-core open file.
113  */
114 struct file {
115 	off_t		f_seekp;	/* seek pointer */
116 	struct fs	*f_fs;		/* pointer to super-block */
117 	union dinode {
118 		struct ufs1_dinode di1;
119 		struct ufs2_dinode di2;
120 	}		f_di;		/* copy of on-disk inode */
121 	int		f_nindir[UFS_NIADDR];
122 					/* number of blocks mapped by
123 					   indirect block at level i */
124 	char		*f_blk[UFS_NIADDR];	/* buffer for indirect block at
125 					   level i */
126 	size_t		f_blksize[UFS_NIADDR];
127 					/* size of buffer */
128 	ufs2_daddr_t	f_blkno[UFS_NIADDR];/* disk address of block in buffer */
129 	ufs2_daddr_t	f_buf_blkno;	/* block number of data block */
130 	char		*f_buf;		/* buffer for data block */
131 	size_t		f_buf_size;	/* size of data block */
132 	int		f_inumber;	/* inumber */
133 };
134 #define DIP(fp, field) \
135 	((fp)->f_fs->fs_magic == FS_UFS1_MAGIC ? \
136 	(fp)->f_di.di1.field : (fp)->f_di.di2.field)
137 
138 typedef struct ufs_mnt {
139 	char			*um_dev;
140 	int			um_fd;
141 	STAILQ_ENTRY(ufs_mnt)	um_link;
142 } ufs_mnt_t;
143 
144 typedef STAILQ_HEAD(ufs_mnt_list, ufs_mnt) ufs_mnt_list_t;
145 static ufs_mnt_list_t mnt_list = STAILQ_HEAD_INITIALIZER(mnt_list);
146 
147 static int	read_inode(ino_t, struct open_file *);
148 static int	block_map(struct open_file *, ufs2_daddr_t, ufs2_daddr_t *);
149 static int	buf_read_file(struct open_file *, char **, size_t *);
150 static int	buf_write_file(struct open_file *, const char *, size_t *);
151 static int	search_directory(char *, struct open_file *, ino_t *);
152 static int	ufs_use_sa_read(void *, off_t, void **, int);
153 
154 /* from ffs_subr.c */
155 int	ffs_sbget(void *, struct fs **, off_t, char *,
156 	    int (*)(void *, off_t, void **, int));
157 
158 /*
159  * Read a new inode into a file structure.
160  */
161 static int
162 read_inode(ino_t inumber, struct open_file *f)
163 {
164 	struct file *fp = (struct file *)f->f_fsdata;
165 	struct fs *fs = fp->f_fs;
166 	char *buf;
167 	size_t rsize;
168 	int rc;
169 
170 	if (fs == NULL)
171 	    panic("fs == NULL");
172 
173 	/*
174 	 * Read inode and save it.
175 	 */
176 	buf = malloc(fs->fs_bsize);
177 	twiddle(1);
178 	rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
179 		fsbtodb(fs, ino_to_fsba(fs, inumber)), fs->fs_bsize,
180 		buf, &rsize);
181 	if (rc)
182 		goto out;
183 	if (rsize != fs->fs_bsize) {
184 		rc = EIO;
185 		goto out;
186 	}
187 
188 	if (fp->f_fs->fs_magic == FS_UFS1_MAGIC)
189 		fp->f_di.di1 = ((struct ufs1_dinode *)buf)
190 		    [ino_to_fsbo(fs, inumber)];
191 	else
192 		fp->f_di.di2 = ((struct ufs2_dinode *)buf)
193 		    [ino_to_fsbo(fs, inumber)];
194 
195 	/*
196 	 * Clear out the old buffers
197 	 */
198 	{
199 		int level;
200 
201 		for (level = 0; level < UFS_NIADDR; level++)
202 			fp->f_blkno[level] = -1;
203 		fp->f_buf_blkno = -1;
204 	}
205 	fp->f_seekp = 0;
206 	fp->f_inumber = inumber;
207 out:
208 	free(buf);
209 	return (rc);
210 }
211 
212 /*
213  * Given an offset in a file, find the disk block number that
214  * contains that block.
215  */
216 static int
217 block_map(struct open_file *f, ufs2_daddr_t file_block,
218     ufs2_daddr_t *disk_block_p)
219 {
220 	struct file *fp = (struct file *)f->f_fsdata;
221 	struct fs *fs = fp->f_fs;
222 	int level;
223 	int idx;
224 	ufs2_daddr_t ind_block_num;
225 	int rc;
226 
227 	/*
228 	 * Index structure of an inode:
229 	 *
230 	 * di_db[0..UFS_NDADDR-1] hold block numbers for blocks
231 	 *			0..UFS_NDADDR-1
232 	 *
233 	 * di_ib[0]		index block 0 is the single indirect block
234 	 *			holds block numbers for blocks
235 	 *			UFS_NDADDR .. UFS_NDADDR + NINDIR(fs)-1
236 	 *
237 	 * di_ib[1]		index block 1 is the double indirect block
238 	 *			holds block numbers for INDEX blocks for blocks
239 	 *			UFS_NDADDR + NINDIR(fs) ..
240 	 *			UFS_NDADDR + NINDIR(fs) + NINDIR(fs)**2 - 1
241 	 *
242 	 * di_ib[2]		index block 2 is the triple indirect block
243 	 *			holds block numbers for double-indirect
244 	 *			blocks for blocks
245 	 *			UFS_NDADDR + NINDIR(fs) + NINDIR(fs)**2 ..
246 	 *			UFS_NDADDR + NINDIR(fs) + NINDIR(fs)**2
247 	 *				+ NINDIR(fs)**3 - 1
248 	 */
249 
250 	if (file_block < UFS_NDADDR) {
251 		/* Direct block. */
252 		*disk_block_p = DIP(fp, di_db[file_block]);
253 		return (0);
254 	}
255 
256 	file_block -= UFS_NDADDR;
257 
258 	/*
259 	 * nindir[0] = NINDIR
260 	 * nindir[1] = NINDIR**2
261 	 * nindir[2] = NINDIR**3
262 	 *	etc
263 	 */
264 	for (level = 0; level < UFS_NIADDR; level++) {
265 		if (file_block < fp->f_nindir[level])
266 			break;
267 		file_block -= fp->f_nindir[level];
268 	}
269 	if (level == UFS_NIADDR) {
270 		/* Block number too high */
271 		return (EFBIG);
272 	}
273 
274 	ind_block_num = DIP(fp, di_ib[level]);
275 
276 	for (; level >= 0; level--) {
277 		if (ind_block_num == 0) {
278 			*disk_block_p = 0;	/* missing */
279 			return (0);
280 		}
281 
282 		if (fp->f_blkno[level] != ind_block_num) {
283 			if (fp->f_blk[level] == (char *)0)
284 				fp->f_blk[level] =
285 					malloc(fs->fs_bsize);
286 			twiddle(1);
287 			rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
288 				fsbtodb(fp->f_fs, ind_block_num),
289 				fs->fs_bsize,
290 				fp->f_blk[level],
291 				&fp->f_blksize[level]);
292 			if (rc)
293 				return (rc);
294 			if (fp->f_blksize[level] != fs->fs_bsize)
295 				return (EIO);
296 			fp->f_blkno[level] = ind_block_num;
297 		}
298 
299 		if (level > 0) {
300 			idx = file_block / fp->f_nindir[level - 1];
301 			file_block %= fp->f_nindir[level - 1];
302 		} else
303 			idx = file_block;
304 
305 		if (fp->f_fs->fs_magic == FS_UFS1_MAGIC)
306 			ind_block_num = ((ufs1_daddr_t *)fp->f_blk[level])[idx];
307 		else
308 			ind_block_num = ((ufs2_daddr_t *)fp->f_blk[level])[idx];
309 	}
310 
311 	*disk_block_p = ind_block_num;
312 
313 	return (0);
314 }
315 
316 /*
317  * Write a portion of a file from an internal buffer.
318  */
319 static int
320 buf_write_file(struct open_file *f, const char *buf_p, size_t *size_p)
321 {
322 	struct file *fp = (struct file *)f->f_fsdata;
323 	struct fs *fs = fp->f_fs;
324 	long off;
325 	ufs_lbn_t file_block;
326 	ufs2_daddr_t disk_block;
327 	size_t block_size;
328 	int rc;
329 
330 	/*
331 	 * Calculate the starting block address and offset.
332 	 */
333 	off = blkoff(fs, fp->f_seekp);
334 	file_block = lblkno(fs, fp->f_seekp);
335 	block_size = sblksize(fs, DIP(fp, di_size), file_block);
336 
337 	rc = block_map(f, file_block, &disk_block);
338 	if (rc)
339 		return (rc);
340 
341  	if (disk_block == 0)
342 		/* Because we can't allocate space on the drive */
343 		return (EFBIG);
344 
345 	/*
346 	 * Truncate buffer at end of file, and at the end of
347 	 * this block.
348 	 */
349 	if (*size_p > DIP(fp, di_size) - fp->f_seekp)
350 		*size_p = DIP(fp, di_size) - fp->f_seekp;
351 	if (*size_p > block_size - off)
352 		*size_p = block_size - off;
353 
354 	/*
355 	 * If we don't entirely occlude the block and it's not
356 	 * in memory already, read it in first.
357 	 */
358 	if (((off > 0) || (*size_p + off < block_size)) &&
359 	    (file_block != fp->f_buf_blkno)) {
360 
361 		if (fp->f_buf == (char *)0)
362 			fp->f_buf = malloc(fs->fs_bsize);
363 
364 		twiddle(4);
365 		rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
366 			fsbtodb(fs, disk_block),
367 			block_size, fp->f_buf, &fp->f_buf_size);
368 		if (rc)
369 			return (rc);
370 
371 		fp->f_buf_blkno = file_block;
372 	}
373 
374 	/*
375 	 *	Copy the user data into the cached block.
376 	 */
377 	bcopy(buf_p, fp->f_buf + off, *size_p);
378 
379 	/*
380 	 *	Write the block out to storage.
381 	 */
382 
383 	twiddle(4);
384 	rc = (f->f_dev->dv_strategy)(f->f_devdata, F_WRITE,
385 		fsbtodb(fs, disk_block),
386 		block_size, fp->f_buf, &fp->f_buf_size);
387 	return (rc);
388 }
389 
390 /*
391  * Read a portion of a file into an internal buffer.  Return
392  * the location in the buffer and the amount in the buffer.
393  */
394 static int
395 buf_read_file(struct open_file *f, char **buf_p, size_t *size_p)
396 {
397 	struct file *fp = (struct file *)f->f_fsdata;
398 	struct fs *fs = fp->f_fs;
399 	long off;
400 	ufs_lbn_t file_block;
401 	ufs2_daddr_t disk_block;
402 	size_t block_size;
403 	int rc;
404 
405 	off = blkoff(fs, fp->f_seekp);
406 	file_block = lblkno(fs, fp->f_seekp);
407 	block_size = sblksize(fs, DIP(fp, di_size), file_block);
408 
409 	if (file_block != fp->f_buf_blkno) {
410 		if (fp->f_buf == (char *)0)
411 			fp->f_buf = malloc(fs->fs_bsize);
412 
413 		rc = block_map(f, file_block, &disk_block);
414 		if (rc)
415 			return (rc);
416 
417 		if (disk_block == 0) {
418 			bzero(fp->f_buf, block_size);
419 			fp->f_buf_size = block_size;
420 		} else {
421 			twiddle(4);
422 			rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
423 				fsbtodb(fs, disk_block),
424 				block_size, fp->f_buf, &fp->f_buf_size);
425 			if (rc)
426 				return (rc);
427 		}
428 
429 		fp->f_buf_blkno = file_block;
430 	}
431 
432 	/*
433 	 * Return address of byte in buffer corresponding to
434 	 * offset, and size of remainder of buffer after that
435 	 * byte.
436 	 */
437 	*buf_p = fp->f_buf + off;
438 	*size_p = block_size - off;
439 
440 	/*
441 	 * But truncate buffer at end of file.
442 	 */
443 	if (*size_p > DIP(fp, di_size) - fp->f_seekp)
444 		*size_p = DIP(fp, di_size) - fp->f_seekp;
445 
446 	return (0);
447 }
448 
449 /*
450  * Search a directory for a name and return its
451  * i_number.
452  */
453 static int
454 search_directory(char *name, struct open_file *f, ino_t *inumber_p)
455 {
456 	struct file *fp = (struct file *)f->f_fsdata;
457 	struct direct *dp;
458 	struct direct *edp;
459 	char *buf;
460 	size_t buf_size;
461 	int namlen, length;
462 	int rc;
463 
464 	length = strlen(name);
465 
466 	fp->f_seekp = 0;
467 	while (fp->f_seekp < DIP(fp, di_size)) {
468 		rc = buf_read_file(f, &buf, &buf_size);
469 		if (rc)
470 			return (rc);
471 
472 		dp = (struct direct *)buf;
473 		edp = (struct direct *)(buf + buf_size);
474 		while (dp < edp) {
475 			if (dp->d_ino == (ino_t)0)
476 				goto next;
477 #if BYTE_ORDER == LITTLE_ENDIAN
478 			if (fp->f_fs->fs_maxsymlinklen <= 0)
479 				namlen = dp->d_type;
480 			else
481 #endif
482 				namlen = dp->d_namlen;
483 			if (namlen == length &&
484 			    !strcmp(name, dp->d_name)) {
485 				/* found entry */
486 				*inumber_p = dp->d_ino;
487 				return (0);
488 			}
489 		next:
490 			dp = (struct direct *)((char *)dp + dp->d_reclen);
491 		}
492 		fp->f_seekp += buf_size;
493 	}
494 	return (ENOENT);
495 }
496 
497 /*
498  * Open a file.
499  */
500 static int
501 ufs_open(const char *upath, struct open_file *f)
502 {
503 	char *cp, *ncp;
504 	int c;
505 	ino_t inumber, parent_inumber;
506 	struct file *fp;
507 	struct fs *fs;
508 	int rc;
509 	int nlinks = 0;
510 	char namebuf[MAXPATHLEN+1];
511 	char *buf = NULL;
512 	char *path = NULL;
513 	const char *dev;
514 	ufs_mnt_t *mnt;
515 
516 	/* allocate file system specific data structure */
517 	errno = 0;
518 	fp = calloc(1, sizeof(struct file));
519 	if (fp == NULL)
520 		return (errno);
521 	f->f_fsdata = (void *)fp;
522 
523 	dev = disk_fmtdev(f->f_devdata);
524 	/* Is this device mounted? */
525 	STAILQ_FOREACH(mnt, &mnt_list, um_link) {
526 		if (strcmp(dev, mnt->um_dev) == 0)
527 			break;
528 	}
529 
530 	if (mnt == NULL) {
531 		/* read super block */
532 		twiddle(1);
533 		if ((rc = ffs_sbget(f, &fs, STDSB_NOHASHFAIL, "stand",
534 		     ufs_use_sa_read)) != 0) {
535 			goto out;
536 		}
537 	} else {
538 		struct open_file *sbf;
539 		struct file *sfp;
540 
541 		/* get superblock from mounted file system */
542 		sbf = fd2open_file(mnt->um_fd);
543 		sfp = sbf->f_fsdata;
544 		fs = sfp->f_fs;
545 	}
546 	fp->f_fs = fs;
547 
548 	/*
549 	 * Calculate indirect block levels.
550 	 */
551 	{
552 		ufs2_daddr_t mult;
553 		int level;
554 
555 		mult = 1;
556 		for (level = 0; level < UFS_NIADDR; level++) {
557 			mult *= NINDIR(fs);
558 			fp->f_nindir[level] = mult;
559 		}
560 	}
561 
562 	inumber = UFS_ROOTINO;
563 	if ((rc = read_inode(inumber, f)) != 0)
564 		goto out;
565 
566 	cp = path = strdup(upath);
567 	if (path == NULL) {
568 	    rc = ENOMEM;
569 	    goto out;
570 	}
571 	while (*cp) {
572 
573 		/*
574 		 * Remove extra separators
575 		 */
576 		while (*cp == '/')
577 			cp++;
578 		if (*cp == '\0')
579 			break;
580 
581 		/*
582 		 * Check that current node is a directory.
583 		 */
584 		if ((DIP(fp, di_mode) & IFMT) != IFDIR) {
585 			rc = ENOTDIR;
586 			goto out;
587 		}
588 
589 		/*
590 		 * Get next component of path name.
591 		 */
592 		{
593 			int len = 0;
594 
595 			ncp = cp;
596 			while ((c = *cp) != '\0' && c != '/') {
597 				if (++len > UFS_MAXNAMLEN) {
598 					rc = ENOENT;
599 					goto out;
600 				}
601 				cp++;
602 			}
603 			*cp = '\0';
604 		}
605 
606 		/*
607 		 * Look up component in current directory.
608 		 * Save directory inumber in case we find a
609 		 * symbolic link.
610 		 */
611 		parent_inumber = inumber;
612 		rc = search_directory(ncp, f, &inumber);
613 		*cp = c;
614 		if (rc)
615 			goto out;
616 
617 		/*
618 		 * Open next component.
619 		 */
620 		if ((rc = read_inode(inumber, f)) != 0)
621 			goto out;
622 
623 		/*
624 		 * Check for symbolic link.
625 		 */
626 		if ((DIP(fp, di_mode) & IFMT) == IFLNK) {
627 			int link_len = DIP(fp, di_size);
628 			int len;
629 
630 			len = strlen(cp);
631 
632 			if (link_len + len > MAXPATHLEN ||
633 			    ++nlinks > MAXSYMLINKS) {
634 				rc = ENOENT;
635 				goto out;
636 			}
637 
638 			bcopy(cp, &namebuf[link_len], len + 1);
639 
640 			if (link_len < fs->fs_maxsymlinklen) {
641 				if (fp->f_fs->fs_magic == FS_UFS1_MAGIC)
642 					cp = (caddr_t)(fp->f_di.di1.di_db);
643 				else
644 					cp = (caddr_t)(fp->f_di.di2.di_db);
645 				bcopy(cp, namebuf, (unsigned) link_len);
646 			} else {
647 				/*
648 				 * Read file for symbolic link
649 				 */
650 				size_t buf_size;
651 				ufs2_daddr_t disk_block;
652 				struct fs *fs = fp->f_fs;
653 
654 				if (!buf)
655 					buf = malloc(fs->fs_bsize);
656 				rc = block_map(f, (ufs2_daddr_t)0, &disk_block);
657 				if (rc)
658 					goto out;
659 
660 				twiddle(1);
661 				rc = (f->f_dev->dv_strategy)(f->f_devdata,
662 					F_READ, fsbtodb(fs, disk_block),
663 					fs->fs_bsize, buf, &buf_size);
664 				if (rc)
665 					goto out;
666 
667 				bcopy((char *)buf, namebuf, (unsigned)link_len);
668 			}
669 
670 			/*
671 			 * If relative pathname, restart at parent directory.
672 			 * If absolute pathname, restart at root.
673 			 */
674 			cp = namebuf;
675 			if (*cp != '/')
676 				inumber = parent_inumber;
677 			else
678 				inumber = (ino_t)UFS_ROOTINO;
679 
680 			if ((rc = read_inode(inumber, f)) != 0)
681 				goto out;
682 		}
683 	}
684 
685 	/*
686 	 * Found terminal component.
687 	 */
688 	rc = 0;
689 	fp->f_seekp = 0;
690 out:
691 	free(buf);
692 	free(path);
693 	if (rc) {
694 		free(fp->f_buf);
695 
696 		if (mnt == NULL && fp->f_fs != NULL) {
697 			free(fp->f_fs->fs_csp);
698 			free(fp->f_fs->fs_si);
699 			free(fp->f_fs);
700 		}
701 		free(fp);
702 	}
703 	return (rc);
704 }
705 
706 /*
707  * A read function for use by standalone-layer routines.
708  */
709 static int
710 ufs_use_sa_read(void *devfd, off_t loc, void **bufp, int size)
711 {
712 	struct open_file *f;
713 	size_t buf_size;
714 	int error;
715 
716 	f = (struct open_file *)devfd;
717 	if ((*bufp = malloc(size)) == NULL)
718 		return (ENOSPC);
719 	error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, loc / DEV_BSIZE,
720 	    size, *bufp, &buf_size);
721 	if (error != 0)
722 		return (error);
723 	if (buf_size != size)
724 		return (EIO);
725 	return (0);
726 }
727 
728 static int
729 ufs_close(struct open_file *f)
730 {
731 	ufs_mnt_t *mnt;
732 	struct file *fp = (struct file *)f->f_fsdata;
733 	int level;
734 	char *dev;
735 
736 	f->f_fsdata = NULL;
737 	if (fp == NULL)
738 		return (0);
739 
740 	for (level = 0; level < UFS_NIADDR; level++) {
741 		free(fp->f_blk[level]);
742 	}
743 	free(fp->f_buf);
744 
745 	dev = disk_fmtdev(f->f_devdata);
746 	STAILQ_FOREACH(mnt, &mnt_list, um_link) {
747 		if (strcmp(dev, mnt->um_dev) == 0)
748 			break;
749 	}
750 
751 	if (mnt == NULL && fp->f_fs != NULL) {
752 		free(fp->f_fs->fs_csp);
753 		free(fp->f_fs->fs_si);
754 		free(fp->f_fs);
755 	}
756 
757 	free(fp);
758 	return (0);
759 }
760 
761 /*
762  * Copy a portion of a file into kernel memory.
763  * Cross block boundaries when necessary.
764  */
765 static int
766 ufs_read(struct open_file *f, void *start, size_t size, size_t *resid)
767 {
768 	struct file *fp = (struct file *)f->f_fsdata;
769 	size_t csize;
770 	char *buf;
771 	size_t buf_size;
772 	int rc = 0;
773 	char *addr = start;
774 
775 	while (size != 0) {
776 		if (fp->f_seekp >= DIP(fp, di_size))
777 			break;
778 
779 		rc = buf_read_file(f, &buf, &buf_size);
780 		if (rc)
781 			break;
782 
783 		csize = size;
784 		if (csize > buf_size)
785 			csize = buf_size;
786 
787 		bcopy(buf, addr, csize);
788 
789 		fp->f_seekp += csize;
790 		addr += csize;
791 		size -= csize;
792 	}
793 	if (resid)
794 		*resid = size;
795 	return (rc);
796 }
797 
798 /*
799  * Write to a portion of an already allocated file.
800  * Cross block boundaries when necessary. Can not
801  * extend the file.
802  */
803 static int
804 ufs_write(struct open_file *f, const void *start, size_t size, size_t *resid)
805 {
806 	struct file *fp = (struct file *)f->f_fsdata;
807 	size_t csize;
808 	int rc = 0;
809 	const char *addr = start;
810 
811 	csize = size;
812 	while ((size != 0) && (csize != 0)) {
813 		if (fp->f_seekp >= DIP(fp, di_size))
814 			break;
815 
816 		if (csize >= 512) csize = 512; /* XXX */
817 
818 		rc = buf_write_file(f, addr, &csize);
819 		if (rc)
820 			break;
821 
822 		fp->f_seekp += csize;
823 		addr += csize;
824 		size -= csize;
825 	}
826 	if (resid)
827 		*resid = size;
828 	return (rc);
829 }
830 
831 static off_t
832 ufs_seek(struct open_file *f, off_t offset, int where)
833 {
834 	struct file *fp = (struct file *)f->f_fsdata;
835 
836 	switch (where) {
837 	case SEEK_SET:
838 		fp->f_seekp = offset;
839 		break;
840 	case SEEK_CUR:
841 		fp->f_seekp += offset;
842 		break;
843 	case SEEK_END:
844 		fp->f_seekp = DIP(fp, di_size) - offset;
845 		break;
846 	default:
847 		errno = EINVAL;
848 		return (-1);
849 	}
850 	return (fp->f_seekp);
851 }
852 
853 static int
854 ufs_stat(struct open_file *f, struct stat *sb)
855 {
856 	struct file *fp = (struct file *)f->f_fsdata;
857 
858 	/* only important stuff */
859 	sb->st_mode = DIP(fp, di_mode);
860 	sb->st_uid = DIP(fp, di_uid);
861 	sb->st_gid = DIP(fp, di_gid);
862 	sb->st_size = DIP(fp, di_size);
863 	sb->st_mtime = DIP(fp, di_mtime);
864 	/*
865 	 * The items below are ufs specific!
866 	 * Other fs types will need their own solution
867 	 * if these fields are needed.
868 	 */
869 	sb->st_ino = fp->f_inumber;
870 	/*
871 	 * We need something to differentiate devs.
872 	 * fs_id is unique but 64bit, we xor the two
873 	 * halves to squeeze it into 32bits.
874 	 */
875 	sb->st_dev = (dev_t)(fp->f_fs->fs_id[0] ^ fp->f_fs->fs_id[1]);
876 
877 	return (0);
878 }
879 
880 static int
881 ufs_readdir(struct open_file *f, struct dirent *d)
882 {
883 	struct file *fp = (struct file *)f->f_fsdata;
884 	struct direct *dp;
885 	char *buf;
886 	size_t buf_size;
887 	int error;
888 
889 	/*
890 	 * assume that a directory entry will not be split across blocks
891 	 */
892 again:
893 	if (fp->f_seekp >= DIP(fp, di_size))
894 		return (ENOENT);
895 	error = buf_read_file(f, &buf, &buf_size);
896 	if (error)
897 		return (error);
898 	dp = (struct direct *)buf;
899 	fp->f_seekp += dp->d_reclen;
900 	if (dp->d_ino == (ino_t)0)
901 		goto again;
902 	d->d_type = dp->d_type;
903 	strcpy(d->d_name, dp->d_name);
904 	return (0);
905 }
906 
907 static int
908 ufs_mount(const char *dev, const char *path, void **data)
909 {
910 	char *fs;
911 	ufs_mnt_t *mnt;
912 	struct open_file *f;
913 
914 	errno = 0;
915 	mnt = calloc(1, sizeof(*mnt));
916 	if (mnt == NULL)
917 		return (errno);
918 	mnt->um_fd = -1;
919 	mnt->um_dev = strdup(dev);
920 	if (mnt->um_dev == NULL)
921 		goto done;
922 
923 	if (asprintf(&fs, "%s%s", dev, path) < 0)
924 		goto done;
925 
926 	mnt->um_fd = open(fs, O_RDONLY);
927 	free(fs);
928 	if (mnt->um_fd == -1)
929 		goto done;
930 
931 	/* Is it ufs file system? */
932 	f = fd2open_file(mnt->um_fd);
933 	if (strcmp(f->f_ops->fs_name, "ufs") == 0)
934 		STAILQ_INSERT_TAIL(&mnt_list, mnt, um_link);
935 	else
936 		errno = ENXIO;
937 
938 done:
939 	if (errno != 0) {
940 		free(mnt->um_dev);
941 		if (mnt->um_fd >= 0)
942 			close(mnt->um_fd);
943 		free(mnt);
944 	} else {
945 		*data = mnt;
946 	}
947 
948 	return (errno);
949 }
950 
951 static int
952 ufs_unmount(const char *dev __unused, void *data)
953 {
954 	ufs_mnt_t *mnt = data;
955 
956 	STAILQ_REMOVE(&mnt_list, mnt, ufs_mnt, um_link);
957 	free(mnt->um_dev);
958 	close(mnt->um_fd);
959 	free(mnt);
960 	return (0);
961 }
962