xref: /illumos-gate/usr/src/boot/libsa/ufs.c (revision c2cd3a449cfa117e3a164f66931fa6c26c762945)
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 
72 /*
73  *	Stand-alone file reading package.
74  */
75 
76 #include <sys/param.h>
77 #include <sys/disklabel.h>
78 #include <sys/time.h>
79 #include <ufs/ufs/dinode.h>
80 #include <ufs/ufs/dir.h>
81 #include <ufs/ffs/fs.h>
82 #include "stand.h"
83 #include "string.h"
84 
85 static int	ufs_open(const char *, struct open_file *);
86 static int	ufs_write(struct open_file *, const void *, size_t, size_t *);
87 static int	ufs_close(struct open_file *);
88 static int	ufs_read(struct open_file *, void *, size_t, size_t *);
89 static off_t	ufs_seek(struct open_file *, off_t, int);
90 static int	ufs_stat(struct open_file *, struct stat *);
91 static int	ufs_readdir(struct open_file *, struct dirent *);
92 
93 struct fs_ops ufs_fsops = {
94 	"ufs",
95 	ufs_open,
96 	ufs_close,
97 	ufs_read,
98 	ufs_write,
99 	ufs_seek,
100 	ufs_stat,
101 	ufs_readdir
102 };
103 
104 /*
105  * In-core open file.
106  */
107 struct file {
108 	off_t		f_seekp;	/* seek pointer */
109 	struct fs	*f_fs;		/* pointer to super-block */
110 	union dinode {
111 		struct ufs1_dinode di1;
112 		struct ufs2_dinode di2;
113 	}		f_di;		/* copy of on-disk inode */
114 	int		f_nindir[NIADDR];
115 					/*
116 					 * number of blocks mapped by
117 					 * indirect block at level i
118 					 */
119 	char		*f_blk[NIADDR];
120 					/*
121 					 * buffer for indirect block at
122 					 * level i
123 					 */
124 	size_t		f_blksize[NIADDR]; /* size of buffer */
125 	ufs2_daddr_t	f_blkno[NIADDR]; /* disk address of block in buffer */
126 	ufs2_daddr_t	f_buf_blkno;	/* block number of data block */
127 	char		*f_buf;		/* buffer for data block */
128 	size_t		f_buf_size;	/* size of data block */
129 };
130 #define	DIP(fp, field) \
131 	((fp)->f_fs->fs_magic == FS_UFS1_MAGIC ? \
132 	(fp)->f_di.di1.field : (fp)->f_di.di2.field)
133 
134 static int	read_inode(ino_t, struct open_file *);
135 static int	block_map(struct open_file *, ufs2_daddr_t, ufs2_daddr_t *);
136 static int	buf_read_file(struct open_file *, char **, size_t *);
137 static int	buf_write_file(struct open_file *, const char *, size_t *);
138 static int	search_directory(char *, struct open_file *, ino_t *);
139 
140 /*
141  * Read a new inode into a file structure.
142  */
143 static int
144 read_inode(ino_t inumber, struct open_file *f)
145 {
146 	struct file *fp = (struct file *)f->f_fsdata;
147 	struct fs *fs = fp->f_fs;
148 	char *buf;
149 	size_t rsize;
150 	int rc;
151 
152 	if (fs == NULL)
153 		panic("fs == NULL");
154 
155 	/*
156 	 * Read inode and save it.
157 	 */
158 	buf = malloc(fs->fs_bsize);
159 	twiddle(1);
160 	rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
161 	    fsbtodb(fs, ino_to_fsba(fs, inumber)), fs->fs_bsize,
162 	    buf, &rsize);
163 	if (rc)
164 		goto out;
165 	if (rsize != fs->fs_bsize) {
166 		rc = EIO;
167 		goto out;
168 	}
169 
170 	if (fp->f_fs->fs_magic == FS_UFS1_MAGIC)
171 		fp->f_di.di1 = ((struct ufs1_dinode *)buf)
172 		    [ino_to_fsbo(fs, inumber)];
173 	else
174 		fp->f_di.di2 = ((struct ufs2_dinode *)buf)
175 		    [ino_to_fsbo(fs, inumber)];
176 
177 	/*
178 	 * Clear out the old buffers
179 	 */
180 	{
181 		int level;
182 
183 		for (level = 0; level < NIADDR; level++)
184 			fp->f_blkno[level] = -1;
185 		fp->f_buf_blkno = -1;
186 	}
187 	fp->f_seekp = 0;
188 out:
189 	free(buf);
190 	return (rc);
191 }
192 
193 /*
194  * Given an offset in a file, find the disk block number that
195  * contains that block.
196  */
197 static int
198 block_map(struct open_file *f, ufs2_daddr_t file_block,
199     ufs2_daddr_t *disk_block_p)
200 {
201 	struct file *fp = (struct file *)f->f_fsdata;
202 	struct fs *fs = fp->f_fs;
203 	int level;
204 	int idx;
205 	ufs2_daddr_t ind_block_num;
206 	int rc;
207 
208 	/*
209 	 * Index structure of an inode:
210 	 *
211 	 * di_db[0..NDADDR-1]	hold block numbers for blocks
212 	 *			0..NDADDR-1
213 	 *
214 	 * di_ib[0]		index block 0 is the single indirect block
215 	 *			holds block numbers for blocks
216 	 *			NDADDR .. NDADDR + NINDIR(fs)-1
217 	 *
218 	 * di_ib[1]		index block 1 is the double indirect block
219 	 *			holds block numbers for INDEX blocks for blocks
220 	 *			NDADDR + NINDIR(fs) ..
221 	 *			NDADDR + NINDIR(fs) + NINDIR(fs)**2 - 1
222 	 *
223 	 * di_ib[2]		index block 2 is the triple indirect block
224 	 *			holds block numbers for double-indirect
225 	 *			blocks for blocks
226 	 *			NDADDR + NINDIR(fs) + NINDIR(fs)**2 ..
227 	 *			NDADDR + NINDIR(fs) + NINDIR(fs)**2
228 	 *				+ NINDIR(fs)**3 - 1
229 	 */
230 
231 	if (file_block < NDADDR) {
232 		/* Direct block. */
233 		*disk_block_p = DIP(fp, di_db[file_block]);
234 		return (0);
235 	}
236 
237 	file_block -= NDADDR;
238 
239 	/*
240 	 * nindir[0] = NINDIR
241 	 * nindir[1] = NINDIR**2
242 	 * nindir[2] = NINDIR**3
243 	 *	etc
244 	 */
245 	for (level = 0; level < NIADDR; level++) {
246 		if (file_block < fp->f_nindir[level])
247 			break;
248 		file_block -= fp->f_nindir[level];
249 	}
250 	if (level == NIADDR) {
251 		/* Block number too high */
252 		return (EFBIG);
253 	}
254 
255 	ind_block_num = DIP(fp, di_ib[level]);
256 
257 	for (; level >= 0; level--) {
258 		if (ind_block_num == 0) {
259 			*disk_block_p = 0;	/* missing */
260 			return (0);
261 		}
262 
263 		if (fp->f_blkno[level] != ind_block_num) {
264 			if (fp->f_blk[level] == NULL)
265 				fp->f_blk[level] =
266 				    malloc(fs->fs_bsize);
267 			twiddle(1);
268 			rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
269 			    fsbtodb(fp->f_fs, ind_block_num),
270 			    fs->fs_bsize,
271 			    fp->f_blk[level],
272 			    &fp->f_blksize[level]);
273 			if (rc)
274 				return (rc);
275 			if (fp->f_blksize[level] != fs->fs_bsize)
276 				return (EIO);
277 			fp->f_blkno[level] = ind_block_num;
278 		}
279 
280 		if (level > 0) {
281 			idx = file_block / fp->f_nindir[level - 1];
282 			file_block %= fp->f_nindir[level - 1];
283 		} else
284 			idx = file_block;
285 
286 		if (fp->f_fs->fs_magic == FS_UFS1_MAGIC)
287 			ind_block_num = ((ufs1_daddr_t *)fp->f_blk[level])[idx];
288 		else
289 			ind_block_num = ((ufs2_daddr_t *)fp->f_blk[level])[idx];
290 	}
291 
292 	*disk_block_p = ind_block_num;
293 
294 	return (0);
295 }
296 
297 /*
298  * Write a portion of a file from an internal buffer.
299  */
300 static int
301 buf_write_file(struct open_file *f, const char *buf_p, size_t *size_p)
302 {
303 	struct file *fp = (struct file *)f->f_fsdata;
304 	struct fs *fs = fp->f_fs;
305 	long off;
306 	ufs_lbn_t file_block;
307 	ufs2_daddr_t disk_block;
308 	size_t block_size;
309 	int rc;
310 
311 	/*
312 	 * Calculate the starting block address and offset.
313 	 */
314 	off = blkoff(fs, fp->f_seekp);
315 	file_block = lblkno(fs, fp->f_seekp);
316 	block_size = sblksize(fs, DIP(fp, di_size), file_block);
317 
318 	rc = block_map(f, file_block, &disk_block);
319 	if (rc)
320 		return (rc);
321 
322 	if (disk_block == 0)
323 		/* Because we can't allocate space on the drive */
324 		return (EFBIG);
325 
326 	/*
327 	 * Truncate buffer at end of file, and at the end of
328 	 * this block.
329 	 */
330 	if (*size_p > DIP(fp, di_size) - fp->f_seekp)
331 		*size_p = DIP(fp, di_size) - fp->f_seekp;
332 	if (*size_p > block_size - off)
333 		*size_p = block_size - off;
334 
335 	/*
336 	 * If we don't entirely occlude the block and it's not
337 	 * in memory already, read it in first.
338 	 */
339 	if (((off > 0) || (*size_p + off < block_size)) &&
340 	    (file_block != fp->f_buf_blkno)) {
341 
342 		if (fp->f_buf == (char *)0)
343 			fp->f_buf = malloc(fs->fs_bsize);
344 
345 		twiddle(8);
346 		rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
347 		    fsbtodb(fs, disk_block),
348 		    block_size, fp->f_buf, &fp->f_buf_size);
349 		if (rc)
350 			return (rc);
351 
352 		fp->f_buf_blkno = file_block;
353 	}
354 
355 	/*
356 	 *	Copy the user data into the cached block.
357 	 */
358 	bcopy(buf_p, fp->f_buf + off, *size_p);
359 
360 	/*
361 	 *	Write the block out to storage.
362 	 */
363 
364 	twiddle(4);
365 	rc = (f->f_dev->dv_strategy)(f->f_devdata, F_WRITE,
366 	    fsbtodb(fs, disk_block),
367 	    block_size, fp->f_buf, &fp->f_buf_size);
368 	return (rc);
369 }
370 
371 /*
372  * Read a portion of a file into an internal buffer.  Return
373  * the location in the buffer and the amount in the buffer.
374  */
375 static int
376 buf_read_file(struct open_file *f, char **buf_p, size_t *size_p)
377 {
378 	struct file *fp = (struct file *)f->f_fsdata;
379 	struct fs *fs = fp->f_fs;
380 	long off;
381 	ufs_lbn_t file_block;
382 	ufs2_daddr_t disk_block;
383 	size_t block_size;
384 	int rc;
385 
386 	off = blkoff(fs, fp->f_seekp);
387 	file_block = lblkno(fs, fp->f_seekp);
388 	block_size = sblksize(fs, DIP(fp, di_size), file_block);
389 
390 	if (file_block != fp->f_buf_blkno) {
391 		if (fp->f_buf == (char *)0)
392 			fp->f_buf = malloc(fs->fs_bsize);
393 
394 		rc = block_map(f, file_block, &disk_block);
395 		if (rc)
396 			return (rc);
397 
398 		if (disk_block == 0) {
399 			bzero(fp->f_buf, block_size);
400 			fp->f_buf_size = block_size;
401 		} else {
402 			twiddle(4);
403 			rc = (f->f_dev->dv_strategy)(f->f_devdata,
404 			    F_READ, fsbtodb(fs, disk_block),
405 			    block_size, fp->f_buf, &fp->f_buf_size);
406 			if (rc)
407 				return (rc);
408 		}
409 
410 		fp->f_buf_blkno = file_block;
411 	}
412 
413 	/*
414 	 * Return address of byte in buffer corresponding to
415 	 * offset, and size of remainder of buffer after that
416 	 * byte.
417 	 */
418 	*buf_p = fp->f_buf + off;
419 	*size_p = block_size - off;
420 
421 	/*
422 	 * But truncate buffer at end of file.
423 	 */
424 	if (*size_p > DIP(fp, di_size) - fp->f_seekp)
425 		*size_p = DIP(fp, di_size) - fp->f_seekp;
426 
427 	return (0);
428 }
429 
430 /*
431  * Search a directory for a name and return its
432  * i_number.
433  */
434 static int
435 search_directory(char *name, struct open_file *f, ino_t *inumber_p)
436 {
437 	struct file *fp = (struct file *)f->f_fsdata;
438 	struct direct *dp;
439 	struct direct *edp;
440 	char *buf;
441 	size_t buf_size;
442 	int namlen, length;
443 	int rc;
444 
445 	length = strlen(name);
446 
447 	fp->f_seekp = 0;
448 	while (fp->f_seekp < DIP(fp, di_size)) {
449 		rc = buf_read_file(f, &buf, &buf_size);
450 		if (rc)
451 			return (rc);
452 
453 		dp = (struct direct *)buf;
454 		edp = (struct direct *)(buf + buf_size);
455 		while (dp < edp) {
456 			if (dp->d_ino == (ino_t)0)
457 				goto next;
458 			namlen = dp->d_namlen;
459 			if (namlen == length &&
460 			    strcmp(name, dp->d_name) == 0) {
461 				/* found entry */
462 				*inumber_p = dp->d_ino;
463 				return (0);
464 			}
465 		next:
466 			dp = (struct direct *)((char *)dp + dp->d_reclen);
467 		}
468 		fp->f_seekp += buf_size;
469 	}
470 	return (ENOENT);
471 }
472 
473 static int sblock_try[] = SBLOCKSEARCH;
474 
475 /*
476  * Open a file.
477  */
478 static int
479 ufs_open(const char *upath, struct open_file *f)
480 {
481 	char *cp, *ncp;
482 	int c;
483 	ino_t inumber, parent_inumber;
484 	struct file *fp;
485 	struct fs *fs;
486 	int i, rc;
487 	size_t buf_size;
488 	int nlinks = 0;
489 	char namebuf[MAXPATHLEN+1];
490 	char *buf = NULL;
491 	char *path = NULL;
492 
493 	/* allocate file system specific data structure */
494 	fp = malloc(sizeof (struct file));
495 	bzero(fp, sizeof (struct file));
496 	f->f_fsdata = (void *)fp;
497 
498 	/* allocate space and read super block */
499 	fs = malloc(SBLOCKSIZE);
500 	fp->f_fs = fs;
501 	twiddle(1);
502 	/*
503 	 * Try reading the superblock in each of its possible locations.
504 	 */
505 	for (i = 0; sblock_try[i] != -1; i++) {
506 		rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
507 		    sblock_try[i] / DEV_BSIZE, SBLOCKSIZE,
508 		    (char *)fs, &buf_size);
509 		if (rc)
510 			goto out;
511 		if ((fs->fs_magic == FS_UFS1_MAGIC ||
512 		    (fs->fs_magic == FS_UFS2_MAGIC &&
513 		    fs->fs_sblockloc == sblock_try[i])) &&
514 		    buf_size == SBLOCKSIZE &&
515 		    fs->fs_bsize <= MAXBSIZE &&
516 		    fs->fs_bsize >= sizeof (struct fs))
517 			break;
518 	}
519 	if (sblock_try[i] == -1) {
520 		rc = EINVAL;
521 		goto out;
522 	}
523 	/*
524 	 * Calculate indirect block levels.
525 	 */
526 	{
527 		ufs2_daddr_t mult;
528 		int level;
529 
530 		mult = 1;
531 		for (level = 0; level < NIADDR; level++) {
532 			mult *= NINDIR(fs);
533 			fp->f_nindir[level] = mult;
534 		}
535 	}
536 
537 	inumber = ROOTINO;
538 	if ((rc = read_inode(inumber, f)) != 0)
539 		goto out;
540 
541 	cp = path = strdup(upath);
542 	if (path == NULL) {
543 		rc = ENOMEM;
544 		goto out;
545 	}
546 	while (*cp) {
547 
548 		/*
549 		 * Remove extra separators
550 		 */
551 		while (*cp == '/')
552 			cp++;
553 		if (*cp == '\0')
554 			break;
555 
556 		/*
557 		 * Check that current node is a directory.
558 		 */
559 		if ((DIP(fp, di_mode) & IFMT) != IFDIR) {
560 			rc = ENOTDIR;
561 			goto out;
562 		}
563 
564 		/*
565 		 * Get next component of path name.
566 		 */
567 		{
568 			int len = 0;
569 
570 			ncp = cp;
571 			while ((c = *cp) != '\0' && c != '/') {
572 				if (++len > UFS_MAXNAMLEN) {
573 					rc = ENOENT;
574 					goto out;
575 				}
576 				cp++;
577 			}
578 			*cp = '\0';
579 		}
580 
581 		/*
582 		 * Look up component in current directory.
583 		 * Save directory inumber in case we find a
584 		 * symbolic link.
585 		 */
586 		parent_inumber = inumber;
587 		rc = search_directory(ncp, f, &inumber);
588 		*cp = c;
589 		if (rc)
590 			goto out;
591 
592 		/*
593 		 * Open next component.
594 		 */
595 		if ((rc = read_inode(inumber, f)) != 0)
596 			goto out;
597 
598 		/*
599 		 * Check for symbolic link.
600 		 */
601 		if ((DIP(fp, di_mode) & IFMT) == IFLNK) {
602 			int link_len = DIP(fp, di_size);
603 			int len;
604 
605 			len = strlen(cp);
606 
607 			if (link_len + len > MAXPATHLEN ||
608 			    ++nlinks > MAXSYMLINKS) {
609 				rc = ENOENT;
610 				goto out;
611 			}
612 
613 			bcopy(cp, &namebuf[link_len], len + 1);
614 
615 			if (link_len < fs->fs_maxsymlinklen) {
616 				if (fp->f_fs->fs_magic == FS_UFS1_MAGIC)
617 					cp = (caddr_t)(fp->f_di.di1.di_db);
618 				else
619 					cp = (caddr_t)(fp->f_di.di2.di_db);
620 				bcopy(cp, namebuf, (unsigned)link_len);
621 			} else {
622 				/*
623 				 * Read file for symbolic link
624 				 */
625 				size_t buf_size;
626 				ufs2_daddr_t disk_block;
627 				struct fs *fs = fp->f_fs;
628 
629 				if (!buf)
630 					buf = malloc(fs->fs_bsize);
631 				rc = block_map(f, (ufs2_daddr_t)0, &disk_block);
632 				if (rc)
633 					goto out;
634 
635 				twiddle(1);
636 				rc = (f->f_dev->dv_strategy)(f->f_devdata,
637 				    F_READ, fsbtodb(fs, disk_block),
638 				    fs->fs_bsize, buf, &buf_size);
639 				if (rc)
640 					goto out;
641 
642 				bcopy((char *)buf, namebuf, (unsigned)link_len);
643 			}
644 
645 			/*
646 			 * If relative pathname, restart at parent directory.
647 			 * If absolute pathname, restart at root.
648 			 */
649 			cp = namebuf;
650 			if (*cp != '/')
651 				inumber = parent_inumber;
652 			else
653 				inumber = (ino_t)ROOTINO;
654 
655 			if ((rc = read_inode(inumber, f)) != 0)
656 				goto out;
657 		}
658 	}
659 
660 	/*
661 	 * Found terminal component.
662 	 */
663 	rc = 0;
664 	fp->f_seekp = 0;
665 out:
666 	if (buf)
667 		free(buf);
668 	if (path)
669 		free(path);
670 	if (rc) {
671 		if (fp->f_buf)
672 			free(fp->f_buf);
673 		free(fp->f_fs);
674 		free(fp);
675 	}
676 	return (rc);
677 }
678 
679 static int
680 ufs_close(struct open_file *f)
681 {
682 	struct file *fp = (struct file *)f->f_fsdata;
683 	int level;
684 
685 	f->f_fsdata = (void *)0;
686 	if (fp == (struct file *)0)
687 		return (0);
688 
689 	for (level = 0; level < NIADDR; level++) {
690 		if (fp->f_blk[level])
691 			free(fp->f_blk[level]);
692 	}
693 	if (fp->f_buf)
694 		free(fp->f_buf);
695 	free(fp->f_fs);
696 	free(fp);
697 	return (0);
698 }
699 
700 /*
701  * Copy a portion of a file into kernel memory.
702  * Cross block boundaries when necessary.
703  */
704 static int
705 ufs_read(struct open_file *f, void *start, size_t size, size_t *resid)
706 {
707 	struct file *fp = (struct file *)f->f_fsdata;
708 	size_t csize;
709 	char *buf;
710 	size_t buf_size;
711 	int rc = 0;
712 	char *addr = start;
713 
714 	while (size != 0) {
715 		if (fp->f_seekp >= DIP(fp, di_size))
716 			break;
717 
718 		rc = buf_read_file(f, &buf, &buf_size);
719 		if (rc)
720 			break;
721 
722 		csize = size;
723 		if (csize > buf_size)
724 			csize = buf_size;
725 
726 		bcopy(buf, addr, csize);
727 
728 		fp->f_seekp += csize;
729 		addr += csize;
730 		size -= csize;
731 	}
732 	if (resid)
733 		*resid = size;
734 	return (rc);
735 }
736 
737 /*
738  * Write to a portion of an already allocated file.
739  * Cross block boundaries when necessary. Can not
740  * extend the file.
741  */
742 static int
743 ufs_write(struct open_file *f, const void *start, size_t size, size_t *resid)
744 {
745 	struct file *fp = (struct file *)f->f_fsdata;
746 	size_t csize;
747 	int rc = 0;
748 	const char *addr = start;
749 
750 	csize = size;
751 	while ((size != 0) && (csize != 0)) {
752 		if (fp->f_seekp >= DIP(fp, di_size))
753 			break;
754 
755 		if (csize >= 512) csize = 512; /* XXX */
756 
757 		rc = buf_write_file(f, addr, &csize);
758 		if (rc)
759 			break;
760 
761 		fp->f_seekp += csize;
762 		addr += csize;
763 		size -= csize;
764 	}
765 	if (resid)
766 		*resid = size;
767 	return (rc);
768 }
769 
770 static off_t
771 ufs_seek(struct open_file *f, off_t offset, int where)
772 {
773 	struct file *fp = (struct file *)f->f_fsdata;
774 
775 	switch (where) {
776 	case SEEK_SET:
777 		fp->f_seekp = offset;
778 		break;
779 	case SEEK_CUR:
780 		fp->f_seekp += offset;
781 		break;
782 	case SEEK_END:
783 		fp->f_seekp = DIP(fp, di_size) - offset;
784 		break;
785 	default:
786 		errno = EINVAL;
787 		return (-1);
788 	}
789 	return (fp->f_seekp);
790 }
791 
792 static int
793 ufs_stat(struct open_file *f, struct stat *sb)
794 {
795 	struct file *fp = (struct file *)f->f_fsdata;
796 
797 	/* only important stuff */
798 	sb->st_mode = DIP(fp, di_mode);
799 	sb->st_uid = DIP(fp, di_uid);
800 	sb->st_gid = DIP(fp, di_gid);
801 	sb->st_size = DIP(fp, di_size);
802 	return (0);
803 }
804 
805 static int
806 ufs_readdir(struct open_file *f, struct dirent *d)
807 {
808 	struct file *fp = (struct file *)f->f_fsdata;
809 	struct direct *dp;
810 	char *buf;
811 	size_t buf_size;
812 	int error;
813 
814 	/*
815 	 * assume that a directory entry will not be split across blocks
816 	 */
817 again:
818 	if (fp->f_seekp >= DIP(fp, di_size))
819 		return (ENOENT);
820 	error = buf_read_file(f, &buf, &buf_size);
821 	if (error)
822 		return (error);
823 	dp = (struct direct *)buf;
824 	fp->f_seekp += dp->d_reclen;
825 	if (dp->d_ino == (ino_t)0)
826 		goto again;
827 
828 	d->d_type = 0;		/* illumos ufs does not have type in direct */
829 	strcpy(d->d_name, dp->d_name);
830 	return (0);
831 }
832