xref: /openbsd/sys/lib/libsa/ufs.c (revision 599546b3) 
1 /*	$OpenBSD: ufs.c,v 1.16 2003/08/11 06:23:09 deraadt Exp $	*/
2 /*	$NetBSD: ufs.c,v 1.16 1996/09/30 16:01:22 ws Exp $	*/
3 
4 /*-
5  * Copyright (c) 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * The Mach Operating System project at Carnegie-Mellon University.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *
36  * Copyright (c) 1990, 1991 Carnegie Mellon University
37  * All Rights Reserved.
38  *
39  * Author: David Golub
40  *
41  * Permission to use, copy, modify and distribute this software and its
42  * documentation is hereby granted, provided that both the copyright
43  * notice and this permission notice appear in all copies of the
44  * software, derivative works or modified versions, and any portions
45  * thereof, and that both notices appear in supporting documentation.
46  *
47  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
48  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
49  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
50  *
51  * Carnegie Mellon requests users of this software to return to
52  *
53  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
54  *  School of Computer Science
55  *  Carnegie Mellon University
56  *  Pittsburgh PA 15213-3890
57  *
58  * any improvements or extensions that they make and grant Carnegie the
59  * rights to redistribute these changes.
60  */
61 
62 /*
63  *	Stand-alone file reading package.
64  */
65 
66 #include <sys/param.h>
67 #include <sys/time.h>
68 #include <sys/stat.h>
69 #include <ufs/ffs/fs.h>
70 #include <ufs/ufs/dinode.h>
71 #include <ufs/ufs/dir.h>
72 #include <lib/libkern/libkern.h>
73 
74 #include "stand.h"
75 #include "ufs.h"
76 
77 /*
78  * In-core open file.
79  */
80 struct file {
81 	off_t		f_seekp;	/* seek pointer */
82 	struct fs	*f_fs;		/* pointer to super-block */
83 	struct dinode	f_di;		/* copy of on-disk inode */
84 	int		f_nindir[NIADDR];
85 					/* number of blocks mapped by
86 					   indirect block at level i */
87 	char		*f_blk[NIADDR];	/* buffer for indirect block at
88 					   level i */
89 	size_t		f_blksize[NIADDR];
90 					/* size of buffer */
91 	daddr_t		f_blkno[NIADDR];/* disk address of block in buffer */
92 	char		*f_buf;		/* buffer for data block */
93 	size_t		f_buf_size;	/* size of data block */
94 	daddr_t		f_buf_blkno;	/* block number of data block */
95 };
96 
97 static int	read_inode(ino_t, struct open_file *);
98 static int	block_map(struct open_file *, daddr_t, daddr_t *);
99 static int	buf_read_file(struct open_file *, char **, size_t *);
100 static int	search_directory(char *, struct open_file *, ino_t *);
101 #ifdef COMPAT_UFS
102 static void	ffs_oldfscompat(struct fs *);
103 #endif
104 
105 /*
106  * Read a new inode into a file structure.
107  */
108 static int
109 read_inode(ino_t inumber, struct open_file *f)
110 {
111 	struct file *fp = (struct file *)f->f_fsdata;
112 	struct fs *fs = fp->f_fs;
113 	char *buf;
114 	size_t rsize;
115 	int rc;
116 
117 	/*
118 	 * Read inode and save it.
119 	 */
120 	buf = alloc(fs->fs_bsize);
121 	twiddle();
122 	rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
123 	    fsbtodb(fs, ino_to_fsba(fs, inumber)), fs->fs_bsize,
124 	    buf, &rsize);
125 	if (rc)
126 		goto out;
127 	if (rsize != (size_t)fs->fs_bsize) {
128 		rc = EIO;
129 		goto out;
130 	}
131 
132 	{
133 		struct dinode *dp;
134 
135 		dp = (struct dinode *)buf;
136 		fp->f_di = dp[ino_to_fsbo(fs, inumber)];
137 	}
138 
139 	/*
140 	 * Clear out the old buffers
141 	 */
142 	{
143 		int level;
144 
145 		for (level = 0; level < NIADDR; level++)
146 			fp->f_blkno[level] = -1;
147 		fp->f_buf_blkno = -1;
148 	}
149 out:
150 	free(buf, fs->fs_bsize);
151 	return (rc);
152 }
153 
154 /*
155  * Given an offset in a file, find the disk block number that
156  * contains that block.
157  */
158 static int
159 block_map(struct open_file *f, daddr_t file_block, daddr_t *disk_block_p)
160 {
161 	struct file *fp = (struct file *)f->f_fsdata;
162 	daddr_t ind_block_num, *ind_p;
163 	struct fs *fs = fp->f_fs;
164 	int level, idx, rc;
165 
166 	/*
167 	 * Index structure of an inode:
168 	 *
169 	 * di_db[0..NDADDR-1]	hold block numbers for blocks
170 	 *			0..NDADDR-1
171 	 *
172 	 * di_ib[0]		index block 0 is the single indirect block
173 	 *			holds block numbers for blocks
174 	 *			NDADDR .. NDADDR + NINDIR(fs)-1
175 	 *
176 	 * di_ib[1]		index block 1 is the double indirect block
177 	 *			holds block numbers for INDEX blocks for blocks
178 	 *			NDADDR + NINDIR(fs) ..
179 	 *			NDADDR + NINDIR(fs) + NINDIR(fs)**2 - 1
180 	 *
181 	 * di_ib[2]		index block 2 is the triple indirect block
182 	 *			holds block numbers for double-indirect
183 	 *			blocks for blocks
184 	 *			NDADDR + NINDIR(fs) + NINDIR(fs)**2 ..
185 	 *			NDADDR + NINDIR(fs) + NINDIR(fs)**2
186 	 *				+ NINDIR(fs)**3 - 1
187 	 */
188 
189 	if (file_block < NDADDR) {
190 		/* Direct block. */
191 		*disk_block_p = fp->f_di.di_db[file_block];
192 		return (0);
193 	}
194 
195 	file_block -= NDADDR;
196 
197 	/*
198 	 * nindir[0] = NINDIR
199 	 * nindir[1] = NINDIR**2
200 	 * nindir[2] = NINDIR**3
201 	 *	etc
202 	 */
203 	for (level = 0; level < NIADDR; level++) {
204 		if (file_block < fp->f_nindir[level])
205 			break;
206 		file_block -= fp->f_nindir[level];
207 	}
208 	if (level == NIADDR) {
209 		/* Block number too high */
210 		return (EFBIG);
211 	}
212 
213 	ind_block_num = fp->f_di.di_ib[level];
214 
215 	for (; level >= 0; level--) {
216 		if (ind_block_num == 0) {
217 			*disk_block_p = 0;	/* missing */
218 			return (0);
219 		}
220 
221 		if (fp->f_blkno[level] != ind_block_num) {
222 			if (fp->f_blk[level] == (char *)0)
223 				fp->f_blk[level] =
224 				    alloc(fs->fs_bsize);
225 			twiddle();
226 			rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
227 			    fsbtodb(fp->f_fs, ind_block_num), fs->fs_bsize,
228 			    fp->f_blk[level], &fp->f_blksize[level]);
229 			if (rc)
230 				return (rc);
231 			if (fp->f_blksize[level] != (size_t)fs->fs_bsize)
232 				return (EIO);
233 			fp->f_blkno[level] = ind_block_num;
234 		}
235 
236 		ind_p = (daddr_t *)fp->f_blk[level];
237 
238 		if (level > 0) {
239 			idx = file_block / fp->f_nindir[level - 1];
240 			file_block %= fp->f_nindir[level - 1];
241 		} else
242 			idx = file_block;
243 
244 		ind_block_num = ind_p[idx];
245 	}
246 
247 	*disk_block_p = ind_block_num;
248 	return (0);
249 }
250 
251 /*
252  * Read a portion of a file into an internal buffer.  Return
253  * the location in the buffer and the amount in the buffer.
254  */
255 static int
256 buf_read_file(struct open_file *f, char **buf_p, size_t *size_p)
257 {
258 	struct file *fp = (struct file *)f->f_fsdata;
259 	struct fs *fs = fp->f_fs;
260 	daddr_t file_block, disk_block;
261 	size_t block_size;
262 	long off;
263 	int rc;
264 
265 	off = blkoff(fs, fp->f_seekp);
266 	file_block = lblkno(fs, fp->f_seekp);
267 	block_size = dblksize(fs, &fp->f_di, file_block);
268 
269 	if (file_block != fp->f_buf_blkno) {
270 		rc = block_map(f, file_block, &disk_block);
271 		if (rc)
272 			return (rc);
273 
274 		if (fp->f_buf == (char *)0)
275 			fp->f_buf = alloc(fs->fs_bsize);
276 
277 		if (disk_block == 0) {
278 			bzero(fp->f_buf, block_size);
279 			fp->f_buf_size = block_size;
280 		} else {
281 			twiddle();
282 			rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
283 			    fsbtodb(fs, disk_block),
284 			    block_size, fp->f_buf, &fp->f_buf_size);
285 			if (rc)
286 				return (rc);
287 		}
288 
289 		fp->f_buf_blkno = file_block;
290 	}
291 
292 	/*
293 	 * Return address of byte in buffer corresponding to
294 	 * offset, and size of remainder of buffer after that
295 	 * byte.
296 	 */
297 	*buf_p = fp->f_buf + off;
298 	*size_p = block_size - off;
299 
300 	/*
301 	 * But truncate buffer at end of file.
302 	 */
303 	if (*size_p > fp->f_di.di_size - fp->f_seekp)
304 		*size_p = fp->f_di.di_size - fp->f_seekp;
305 
306 	return (0);
307 }
308 
309 /*
310  * Search a directory for a name and return its
311  * i_number.
312  */
313 static int
314 search_directory(char *name, struct open_file *f, ino_t *inumber_p)
315 {
316 	struct file *fp = (struct file *)f->f_fsdata;
317 	int namlen, length, rc;
318 	struct direct *dp, *edp;
319 	size_t buf_size;
320 	char *buf;
321 
322 	length = strlen(name);
323 
324 	fp->f_seekp = 0;
325 	while (fp->f_seekp < fp->f_di.di_size) {
326 		rc = buf_read_file(f, &buf, &buf_size);
327 		if (rc)
328 			return (rc);
329 
330 		dp = (struct direct *)buf;
331 		edp = (struct direct *)(buf + buf_size);
332 		while (dp < edp) {
333 			if (dp->d_ino == (ino_t)0)
334 				goto next;
335 #if BYTE_ORDER == LITTLE_ENDIAN
336 			if (fp->f_fs->fs_maxsymlinklen <= 0)
337 				namlen = dp->d_type;
338 			else
339 #endif
340 				namlen = dp->d_namlen;
341 			if (namlen == length &&
342 			    !strcmp(name, dp->d_name)) {
343 				/* found entry */
344 				*inumber_p = dp->d_ino;
345 				return (0);
346 			}
347 		next:
348 			dp = (struct direct *)((char *)dp + dp->d_reclen);
349 		}
350 		fp->f_seekp += buf_size;
351 	}
352 	return (ENOENT);
353 }
354 
355 /*
356  * Open a file.
357  */
358 int
359 ufs_open(char *path, struct open_file *f)
360 {
361 	char namebuf[MAXPATHLEN+1], *cp, *ncp, *buf = NULL;
362 	ino_t inumber, parent_inumber;
363 	int rc, c, nlinks = 0;
364 	struct file *fp;
365 	size_t buf_size;
366 	struct fs *fs;
367 
368 	/* allocate file system specific data structure */
369 	fp = alloc(sizeof(struct file));
370 	bzero(fp, sizeof(struct file));
371 	f->f_fsdata = (void *)fp;
372 
373 	/* allocate space and read super block */
374 	fs = alloc(SBSIZE);
375 	fp->f_fs = fs;
376 	twiddle();
377 	rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
378 	    SBLOCK, SBSIZE, (char *)fs, &buf_size);
379 	if (rc)
380 		goto out;
381 
382 	if (buf_size != SBSIZE || fs->fs_magic != FS_MAGIC ||
383 	    fs->fs_bsize > MAXBSIZE || fs->fs_bsize < sizeof(struct fs)) {
384 		rc = EINVAL;
385 		goto out;
386 	}
387 #ifdef COMPAT_UFS
388 	ffs_oldfscompat(fs);
389 #endif
390 
391 	/*
392 	 * Calculate indirect block levels.
393 	 */
394 	{
395 		int mult;
396 		int level;
397 
398 		mult = 1;
399 		for (level = 0; level < NIADDR; level++) {
400 			mult *= NINDIR(fs);
401 			fp->f_nindir[level] = mult;
402 		}
403 	}
404 
405 	inumber = ROOTINO;
406 	if ((rc = read_inode(inumber, f)) != 0)
407 		goto out;
408 
409 	cp = path;
410 	while (*cp) {
411 
412 		/*
413 		 * Remove extra separators
414 		 */
415 		while (*cp == '/')
416 			cp++;
417 		if (*cp == '\0')
418 			break;
419 
420 		/*
421 		 * Check that current node is a directory.
422 		 */
423 		if ((fp->f_di.di_mode & IFMT) != IFDIR) {
424 			rc = ENOTDIR;
425 			goto out;
426 		}
427 
428 		/*
429 		 * Get next component of path name.
430 		 */
431 		{
432 			int len = 0;
433 
434 			ncp = cp;
435 			while ((c = *cp) != '\0' && c != '/') {
436 				if (++len > MAXNAMLEN) {
437 					rc = ENOENT;
438 					goto out;
439 				}
440 				cp++;
441 			}
442 			*cp = '\0';
443 		}
444 
445 		/*
446 		 * Look up component in current directory.
447 		 * Save directory inumber in case we find a
448 		 * symbolic link.
449 		 */
450 		parent_inumber = inumber;
451 		rc = search_directory(ncp, f, &inumber);
452 		*cp = c;
453 		if (rc)
454 			goto out;
455 
456 		/*
457 		 * Open next component.
458 		 */
459 		if ((rc = read_inode(inumber, f)) != 0)
460 			goto out;
461 
462 		/*
463 		 * Check for symbolic link.
464 		 */
465 		if ((fp->f_di.di_mode & IFMT) == IFLNK) {
466 			int link_len = fp->f_di.di_size;
467 			int len;
468 
469 			len = strlen(cp);
470 
471 			if (link_len + len > MAXPATHLEN ||
472 			    ++nlinks > MAXSYMLINKS) {
473 				rc = ENOENT;
474 				goto out;
475 			}
476 
477 			bcopy(cp, &namebuf[link_len], len + 1);
478 
479 			if (link_len < fs->fs_maxsymlinklen) {
480 				bcopy(fp->f_di.di_shortlink, namebuf,
481 				    (unsigned) link_len);
482 			} else {
483 				/*
484 				 * Read file for symbolic link
485 				 */
486 				size_t buf_size;
487 				daddr_t	disk_block;
488 				struct fs *fs = fp->f_fs;
489 
490 				if (!buf)
491 					buf = alloc(fs->fs_bsize);
492 				rc = block_map(f, (daddr_t)0, &disk_block);
493 				if (rc)
494 					goto out;
495 
496 				twiddle();
497 				rc = (f->f_dev->dv_strategy)(f->f_devdata,
498 				    F_READ, fsbtodb(fs, disk_block),
499 				    fs->fs_bsize, buf, &buf_size);
500 				if (rc)
501 					goto out;
502 
503 				bcopy((char *)buf, namebuf, (unsigned)link_len);
504 			}
505 
506 			/*
507 			 * If relative pathname, restart at parent directory.
508 			 * If absolute pathname, restart at root.
509 			 */
510 			cp = namebuf;
511 			if (*cp != '/')
512 				inumber = parent_inumber;
513 			else
514 				inumber = (ino_t)ROOTINO;
515 
516 			if ((rc = read_inode(inumber, f)) != 0)
517 				goto out;
518 		}
519 	}
520 
521 	/*
522 	 * Found terminal component.
523 	 */
524 	rc = 0;
525 out:
526 	if (buf)
527 		free(buf, fs->fs_bsize);
528 	if (rc) {
529 		free(fp->f_fs, SBSIZE);
530 		free(fp, sizeof(struct file));
531 	}
532 	return (rc);
533 }
534 
535 int
536 ufs_close(struct open_file *f)
537 {
538 	struct file *fp = (struct file *)f->f_fsdata;
539 	int level;
540 
541 	f->f_fsdata = (void *)0;
542 	if (fp == (struct file *)0)
543 		return (0);
544 
545 	for (level = 0; level < NIADDR; level++) {
546 		if (fp->f_blk[level])
547 			free(fp->f_blk[level], fp->f_fs->fs_bsize);
548 	}
549 	if (fp->f_buf)
550 		free(fp->f_buf, fp->f_fs->fs_bsize);
551 	free(fp->f_fs, SBSIZE);
552 	free(fp, sizeof(struct file));
553 	return (0);
554 }
555 
556 /*
557  * Copy a portion of a file into kernel memory.
558  * Cross block boundaries when necessary.
559  */
560 int
561 ufs_read(struct open_file *f, void *start, size_t size, size_t *resid)
562 {
563 	struct file *fp = (struct file *)f->f_fsdata;
564 	char *buf, *addr = start;
565 	size_t csize, buf_size;
566 	int rc = 0;
567 
568 	while (size != 0) {
569 		if (fp->f_seekp >= fp->f_di.di_size)
570 			break;
571 
572 		rc = buf_read_file(f, &buf, &buf_size);
573 		if (rc)
574 			break;
575 
576 		csize = size;
577 		if (csize > buf_size)
578 			csize = buf_size;
579 
580 		bcopy(buf, addr, csize);
581 
582 		fp->f_seekp += csize;
583 		addr += csize;
584 		size -= csize;
585 	}
586 	if (resid)
587 		*resid = size;
588 	return (rc);
589 }
590 
591 /*
592  * Not implemented.
593  */
594 int
595 ufs_write(struct open_file *f, void *start, size_t size, size_t *resid)
596 {
597 
598 	return (EROFS);
599 }
600 
601 off_t
602 ufs_seek(struct open_file *f, off_t offset, int where)
603 {
604 	struct file *fp = (struct file *)f->f_fsdata;
605 
606 	switch (where) {
607 	case SEEK_SET:
608 		fp->f_seekp = offset;
609 		break;
610 	case SEEK_CUR:
611 		fp->f_seekp += offset;
612 		break;
613 	case SEEK_END:
614 		fp->f_seekp = fp->f_di.di_size - offset;
615 		break;
616 	default:
617 		return (-1);
618 	}
619 	return (fp->f_seekp);
620 }
621 
622 int
623 ufs_stat(struct open_file *f, struct stat *sb)
624 {
625 	struct file *fp = (struct file *)f->f_fsdata;
626 
627 	/* only important stuff */
628 	sb->st_mode = fp->f_di.di_mode;
629 	sb->st_uid = fp->f_di.di_uid;
630 	sb->st_gid = fp->f_di.di_gid;
631 	sb->st_size = fp->f_di.di_size;
632 	return (0);
633 }
634 
635 #ifndef	NO_READDIR
636 int
637 ufs_readdir(struct open_file *f, char *name)
638 {
639 	struct file *fp = (struct file *)f->f_fsdata;
640 	struct direct *dp, *edp;
641 	size_t buf_size;
642 	int rc, namlen;
643 	char *buf;
644 
645 	if (name == NULL)
646 		fp->f_seekp = 0;
647 	else {
648 			/* end of dir */
649 		if (fp->f_seekp >= fp->f_di.di_size) {
650 			*name = '\0';
651 			return -1;
652 		}
653 
654 		do {
655 			if ((rc = buf_read_file(f, &buf, &buf_size)) != 0)
656 				return rc;
657 
658 			dp = (struct direct *)buf;
659 			edp = (struct direct *)(buf + buf_size);
660 			while (dp < edp && dp->d_ino == (ino_t)0)
661 				dp = (struct direct *)((char *)dp + dp->d_reclen);
662 			fp->f_seekp += buf_size -
663 			    ((u_int8_t *)edp - (u_int8_t *)dp);
664 		} while (dp >= edp);
665 
666 #if BYTE_ORDER == LITTLE_ENDIAN
667 		if (fp->f_fs->fs_maxsymlinklen <= 0)
668 			namlen = dp->d_type;
669 		else
670 #endif
671 			namlen = dp->d_namlen;
672 		strncpy(name, dp->d_name, namlen + 1);
673 
674 		fp->f_seekp += dp->d_reclen;
675 	}
676 
677 	return 0;
678 }
679 #endif
680 
681 #ifdef COMPAT_UFS
682 /*
683  * Sanity checks for old file systems.
684  *
685  * XXX - goes away some day.
686  */
687 static void
688 ffs_oldfscompat(struct fs *fs)
689 {
690 	int i;
691 
692 	fs->fs_npsect = max(fs->fs_npsect, fs->fs_nsect);	/* XXX */
693 	fs->fs_interleave = max(fs->fs_interleave, 1);		/* XXX */
694 	if (fs->fs_postblformat == FS_42POSTBLFMT)		/* XXX */
695 		fs->fs_nrpos = 8;				/* XXX */
696 	if (fs->fs_inodefmt < FS_44INODEFMT) {			/* XXX */
697 		quad_t sizepb = fs->fs_bsize;			/* XXX */
698 								/* XXX */
699 		fs->fs_maxfilesize = fs->fs_bsize * NDADDR - 1;	/* XXX */
700 		for (i = 0; i < NIADDR; i++) {			/* XXX */
701 			sizepb *= NINDIR(fs);			/* XXX */
702 			fs->fs_maxfilesize += sizepb;		/* XXX */
703 		}						/* XXX */
704 		fs->fs_qbmask = ~fs->fs_bmask;			/* XXX */
705 		fs->fs_qfmask = ~fs->fs_fmask;			/* XXX */
706 	}							/* XXX */
707 }
708 #endif
709