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ufs.c revision 1.44
      1 /*	$NetBSD: ufs.c,v 1.44 2005/02/26 22:58:57 perry Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * The Mach Operating System project at Carnegie-Mellon University.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  *
     34  *
     35  * Copyright (c) 1990, 1991 Carnegie Mellon University
     36  * All Rights Reserved.
     37  *
     38  * Author: David Golub
     39  *
     40  * Permission to use, copy, modify and distribute this software and its
     41  * documentation is hereby granted, provided that both the copyright
     42  * notice and this permission notice appear in all copies of the
     43  * software, derivative works or modified versions, and any portions
     44  * thereof, and that both notices appear in supporting documentation.
     45  *
     46  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     47  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
     48  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     49  *
     50  * Carnegie Mellon requests users of this software to return to
     51  *
     52  *  Software Distribution Coordinator  or  Software.Distribution (at) CS.CMU.EDU
     53  *  School of Computer Science
     54  *  Carnegie Mellon University
     55  *  Pittsburgh PA 15213-3890
     56  *
     57  * any improvements or extensions that they make and grant Carnegie the
     58  * rights to redistribute these changes.
     59  */
     60 
     61 /*
     62  *	Stand-alone file reading package for UFS and LFS filesystems.
     63  */
     64 
     65 #include <sys/param.h>
     66 #include <sys/time.h>
     67 #include <ufs/ufs/dinode.h>
     68 #include <ufs/ufs/dir.h>
     69 #ifdef LIBSA_LFS
     70 #include <sys/queue.h>
     71 #include <sys/mount.h>			/* XXX for MNAMELEN */
     72 #include <ufs/lfs/lfs.h>
     73 #else
     74 #include <ufs/ffs/fs.h>
     75 #endif
     76 #ifdef _STANDALONE
     77 #include <lib/libkern/libkern.h>
     78 #else
     79 #include <string.h>
     80 #endif
     81 
     82 #include "stand.h"
     83 #ifdef LIBSA_LFS
     84 #include "lfs.h"
     85 #else
     86 #include "ufs.h"
     87 #endif
     88 
     89 /* If this file is compiled by itself, build ufs (aka ffsv1) support */
     90 #if !defined(LIBSA_FFSv2) && !defined(LIBSA_LFS)
     91 #define LIBSA_FFSv1
     92 #endif
     93 
     94 #if defined(LIBSA_FS_SINGLECOMPONENT) && !defined(LIBSA_NO_FS_SYMLINK)
     95 #define LIBSA_NO_FS_SYMLINK
     96 #endif
     97 #if defined(COMPAT_UFS) && defined(LIBSA_NO_COMPAT_UFS)
     98 #undef COMPAT_UFS
     99 #endif
    100 
    101 #ifdef LIBSA_LFS
    102 /*
    103  * In-core LFS superblock.  This exists only to placate the macros in lfs.h,
    104  */
    105 struct fs {
    106 	struct dlfs	lfs_dlfs;
    107 };
    108 #define fs_magic	lfs_magic
    109 #define fs_maxsymlinklen lfs_maxsymlinklen
    110 
    111 #define FS_MAGIC	LFS_MAGIC
    112 #define SBLOCKSIZE	LFS_SBPAD
    113 #define SBLOCKOFFSET	LFS_LABELPAD
    114 #else
    115 /* NB ufs2 doesn't use the common suberblock code... */
    116 #define FS_MAGIC	FS_UFS1_MAGIC
    117 #define SBLOCKOFFSET	SBLOCK_UFS1
    118 #endif
    119 
    120 #if defined(LIBSA_NO_TWIDDLE)
    121 #define twiddle()
    122 #endif
    123 
    124 #undef cgstart
    125 #if defined(LIBSA_FFSv2)
    126 #define cgstart(fc, c) cgstart_ufs2((fs), (c))
    127 #else
    128 #define cgstart(fc, c) cgstart_ufs1((fs), (c))
    129 #endif
    130 
    131 #ifndef ufs_dinode
    132 #define ufs_dinode	ufs1_dinode
    133 #endif
    134 #ifndef indp_t
    135 #define indp_t		uint32_t
    136 #endif
    137 #ifndef FSBTODB
    138 #define FSBTODB(fs, indp) fsbtodb(fs, indp)
    139 #endif
    140 
    141 /*
    142  * To avoid having a lot of filesystem-block sized buffers lurking (which
    143  * could be 32k) we only keep a few entries of the indirect block map.
    144  * With 8k blocks, 2^8 blocks is ~500k so we reread the indirect block
    145  * ~13 times pulling in a 6M kernel.
    146  * The cache size must be smaller than the smallest filesystem block,
    147  * so LN2_IND_CACHE_SZ <= 9 (UFS2 and 4k blocks).
    148  */
    149 #define LN2_IND_CACHE_SZ	6
    150 #define IND_CACHE_SZ		(1 << LN2_IND_CACHE_SZ)
    151 #define IND_CACHE_MASK		(IND_CACHE_SZ - 1)
    152 
    153 /*
    154  * In-core open file.
    155  */
    156 struct file {
    157 	off_t		f_seekp;	/* seek pointer */
    158 	struct fs	*f_fs;		/* pointer to super-block */
    159 	struct ufs_dinode	f_di;		/* copy of on-disk inode */
    160 	uint		f_nishift;	/* for blocks in indirect block */
    161 	indp_t		f_ind_cache_block;
    162 	indp_t		f_ind_cache[IND_CACHE_SZ];
    163 
    164 	char		*f_buf;		/* buffer for data block */
    165 	size_t		f_buf_size;	/* size of data block */
    166 	daddr_t		f_buf_blkno;	/* block number of data block */
    167 };
    168 
    169 static int read_inode(ino_t, struct open_file *);
    170 static int block_map(struct open_file *, indp_t, indp_t *);
    171 static int buf_read_file(struct open_file *, char **, size_t *);
    172 static int search_directory(const char *, int, struct open_file *, ino_t *);
    173 #ifdef LIBSA_FFSv1
    174 static void ffs_oldfscompat(struct fs *);
    175 #endif
    176 #ifdef LIBSA_FFSv2
    177 static int ffs_find_superblock(struct open_file *, struct fs *);
    178 #endif
    179 
    180 #ifdef LIBSA_LFS
    181 /*
    182  * Find an inode's block.  Look it up in the ifile.  Whee!
    183  */
    184 static int
    185 find_inode_sector(ino_t inumber, struct open_file *f, daddr_t *isp)
    186 {
    187 	struct file *fp = (struct file *)f->f_fsdata;
    188 	struct fs *fs = fp->f_fs;
    189 	daddr_t ifileent_blkno;
    190 	char *ent_in_buf;
    191 	size_t buf_after_ent;
    192 	int rc;
    193 
    194 	rc = read_inode(fs->lfs_ifile, f);
    195 	if (rc)
    196 		return (rc);
    197 
    198 	ifileent_blkno =
    199 	    (inumber / fs->lfs_ifpb) + fs->lfs_cleansz + fs->lfs_segtabsz;
    200 	fp->f_seekp = (off_t)ifileent_blkno * fs->fs_bsize +
    201 	    (inumber % fs->lfs_ifpb) * sizeof (IFILE_Vx);
    202 	rc = buf_read_file(f, &ent_in_buf, &buf_after_ent);
    203 	if (rc)
    204 		return (rc);
    205 	/* make sure something's not badly wrong, but don't panic. */
    206 	if (buf_after_ent < sizeof (IFILE_Vx))
    207 		return (EINVAL);
    208 
    209 	*isp = FSBTODB(fs, ((IFILE_Vx *)ent_in_buf)->if_daddr);
    210 	if (*isp == LFS_UNUSED_DADDR)	/* again, something badly wrong */
    211 		return (EINVAL);
    212 	return (0);
    213 }
    214 #endif
    215 
    216 /*
    217  * Read a new inode into a file structure.
    218  */
    219 static int
    220 read_inode(ino_t inumber, struct open_file *f)
    221 {
    222 	struct file *fp = (struct file *)f->f_fsdata;
    223 	struct fs *fs = fp->f_fs;
    224 	char *buf;
    225 	ssize_t rsize;
    226 	int rc;
    227 	daddr_t inode_sector;
    228 #ifdef LIBSA_LFS
    229 	struct ufs_dinode *dip;
    230 	int cnt;
    231 #endif
    232 
    233 #ifdef LIBSA_LFS
    234 	if (inumber == fs->lfs_ifile)
    235 		inode_sector = FSBTODB(fs, fs->lfs_idaddr);
    236 	else if ((rc = find_inode_sector(inumber, f, &inode_sector)) != 0)
    237 		return (rc);
    238 #else
    239 	inode_sector = FSBTODB(fs, ino_to_fsba(fs, inumber));
    240 #endif
    241 
    242 	/*
    243 	 * Read inode and save it.
    244 	 */
    245 	buf = fp->f_buf;
    246 	twiddle();
    247 	rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
    248 	    inode_sector, fs->fs_bsize, buf, &rsize);
    249 	if (rc)
    250 		return rc;
    251 	if (rsize != (ssize_t)fs->fs_bsize)
    252 		return EIO;
    253 
    254 #ifdef LIBSA_LFS
    255 	cnt = INOPBx(fs);
    256 	dip = (struct ufs_dinode *)buf + (cnt - 1);
    257 	for (; dip->di_inumber != inumber; --dip) {
    258 		/* kernel code panics, but boot blocks which panic are Bad. */
    259 		if (--cnt == 0)
    260 			return EINVAL;
    261 	}
    262 	fp->f_di = *dip;
    263 #else
    264 	fp->f_di = ((struct ufs_dinode *)buf)[ino_to_fsbo(fs, inumber)];
    265 #endif
    266 
    267 	/*
    268 	 * Clear out the old buffers
    269 	 */
    270 	fp->f_ind_cache_block = ~0;
    271 	fp->f_buf_blkno = -1;
    272 	return (rc);
    273 }
    274 
    275 /*
    276  * Given an offset in a file, find the disk block number that
    277  * contains that block.
    278  */
    279 static int
    280 block_map(struct open_file *f, indp_t file_block, indp_t *disk_block_p)
    281 {
    282 	struct file *fp = (struct file *)f->f_fsdata;
    283 	struct fs *fs = fp->f_fs;
    284 	unsigned level;
    285 	indp_t ind_cache;
    286 	indp_t ind_block_num;
    287 	ssize_t rsize;
    288 	int rc;
    289 	indp_t *buf = (void *)fp->f_buf;
    290 
    291 	/*
    292 	 * Index structure of an inode:
    293 	 *
    294 	 * di_db[0..NDADDR-1]	hold block numbers for blocks
    295 	 *			0..NDADDR-1
    296 	 *
    297 	 * di_ib[0]		index block 0 is the single indirect block
    298 	 *			holds block numbers for blocks
    299 	 *			NDADDR .. NDADDR + NINDIR(fs)-1
    300 	 *
    301 	 * di_ib[1]		index block 1 is the double indirect block
    302 	 *			holds block numbers for INDEX blocks for blocks
    303 	 *			NDADDR + NINDIR(fs) ..
    304 	 *			NDADDR + NINDIR(fs) + NINDIR(fs)**2 - 1
    305 	 *
    306 	 * di_ib[2]		index block 2 is the triple indirect block
    307 	 *			holds block numbers for double-indirect
    308 	 *			blocks for blocks
    309 	 *			NDADDR + NINDIR(fs) + NINDIR(fs)**2 ..
    310 	 *			NDADDR + NINDIR(fs) + NINDIR(fs)**2
    311 	 *				+ NINDIR(fs)**3 - 1
    312 	 */
    313 
    314 	if (file_block < NDADDR) {
    315 		/* Direct block. */
    316 		*disk_block_p = fp->f_di.di_db[file_block];
    317 		return (0);
    318 	}
    319 
    320 	file_block -= NDADDR;
    321 
    322 	ind_cache = file_block >> LN2_IND_CACHE_SZ;
    323 	if (ind_cache == fp->f_ind_cache_block) {
    324 		*disk_block_p = fp->f_ind_cache[file_block & IND_CACHE_MASK];
    325 		return 0;
    326 	}
    327 
    328 	for (level = 0;;) {
    329 		level += fp->f_nishift;
    330 		if (file_block < (indp_t)1 << level)
    331 			break;
    332 		if (level > NIADDR * fp->f_nishift)
    333 			/* Block number too high */
    334 			return (EFBIG);
    335 		file_block -= (indp_t)1 << level;
    336 	}
    337 
    338 	ind_block_num = fp->f_di.di_ib[level / fp->f_nishift - 1];
    339 
    340 	for (;;) {
    341 		level -= fp->f_nishift;
    342 		if (ind_block_num == 0) {
    343 			*disk_block_p = 0;	/* missing */
    344 			return (0);
    345 		}
    346 
    347 		twiddle();
    348 		/*
    349 		 * If we were feeling brave, we could work out the number
    350 		 * of the disk sector and read a single disk sector instead
    351 		 * of a filesystem block.
    352 		 * However we don't do this very often anyway...
    353 		 */
    354 		rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
    355 			FSBTODB(fp->f_fs, ind_block_num), fs->fs_bsize,
    356 			buf, &rsize);
    357 		if (rc)
    358 			return (rc);
    359 		if (rsize != (ssize_t)fs->fs_bsize)
    360 			return EIO;
    361 		ind_block_num = buf[file_block >> level];
    362 		if (level == 0)
    363 			break;
    364 		file_block &= (1 << level) - 1;
    365 	}
    366 
    367 	/* Save the part of the block that contains this sector */
    368 	memcpy(fp->f_ind_cache, &buf[file_block & ~IND_CACHE_MASK],
    369 	    IND_CACHE_SZ * sizeof fp->f_ind_cache[0]);
    370 	fp->f_ind_cache_block = ind_cache;
    371 
    372 	*disk_block_p = ind_block_num;
    373 
    374 	return (0);
    375 }
    376 
    377 /*
    378  * Read a portion of a file into an internal buffer.
    379  * Return the location in the buffer and the amount in the buffer.
    380  */
    381 static int
    382 buf_read_file(struct open_file *f, char **buf_p, size_t *size_p)
    383 {
    384 	struct file *fp = (struct file *)f->f_fsdata;
    385 	struct fs *fs = fp->f_fs;
    386 	long off;
    387 	indp_t file_block;
    388 	indp_t disk_block;
    389 	size_t block_size;
    390 	int rc;
    391 
    392 	off = blkoff(fs, fp->f_seekp);
    393 	file_block = lblkno(fs, fp->f_seekp);
    394 #ifdef LIBSA_LFS
    395 	block_size = dblksize(fs, &fp->f_di, file_block);
    396 #else
    397 	block_size = sblksize(fs, (int64_t)fp->f_di.di_size, file_block);
    398 #endif
    399 
    400 	if (file_block != fp->f_buf_blkno) {
    401 		rc = block_map(f, file_block, &disk_block);
    402 		if (rc)
    403 			return (rc);
    404 
    405 		if (disk_block == 0) {
    406 			memset(fp->f_buf, 0, block_size);
    407 			fp->f_buf_size = block_size;
    408 		} else {
    409 			twiddle();
    410 			rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
    411 				FSBTODB(fs, disk_block),
    412 				block_size, fp->f_buf, &fp->f_buf_size);
    413 			if (rc)
    414 				return (rc);
    415 		}
    416 
    417 		fp->f_buf_blkno = file_block;
    418 	}
    419 
    420 	/*
    421 	 * Return address of byte in buffer corresponding to
    422 	 * offset, and size of remainder of buffer after that
    423 	 * byte.
    424 	 */
    425 	*buf_p = fp->f_buf + off;
    426 	*size_p = block_size - off;
    427 
    428 	/*
    429 	 * But truncate buffer at end of file.
    430 	 */
    431 	if (*size_p > fp->f_di.di_size - fp->f_seekp)
    432 		*size_p = fp->f_di.di_size - fp->f_seekp;
    433 
    434 	return (0);
    435 }
    436 
    437 /*
    438  * Search a directory for a name and return its
    439  * inode number.
    440  */
    441 static int
    442 search_directory(const char *name, int length, struct open_file *f,
    443     ino_t *inumber_p)
    444 {
    445 	struct file *fp = (struct file *)f->f_fsdata;
    446 	struct direct *dp;
    447 	struct direct *edp;
    448 	char *buf;
    449 	size_t buf_size;
    450 	int namlen;
    451 	int rc;
    452 
    453 	fp->f_seekp = 0;
    454 	while (fp->f_seekp < (off_t)fp->f_di.di_size) {
    455 		rc = buf_read_file(f, &buf, &buf_size);
    456 		if (rc)
    457 			return (rc);
    458 
    459 		dp = (struct direct *)buf;
    460 		edp = (struct direct *)(buf + buf_size);
    461 		for (;dp < edp; dp = (void *)((char *)dp + dp->d_reclen)) {
    462 			if (dp->d_reclen <= 0)
    463 				break;
    464 			if (dp->d_ino == (ino_t)0)
    465 				continue;
    466 #if BYTE_ORDER == LITTLE_ENDIAN
    467 			if (fp->f_fs->fs_maxsymlinklen <= 0)
    468 				namlen = dp->d_type;
    469 			else
    470 #endif
    471 				namlen = dp->d_namlen;
    472 			if (namlen == length &&
    473 			    !memcmp(name, dp->d_name, length)) {
    474 				/* found entry */
    475 				*inumber_p = dp->d_ino;
    476 				return (0);
    477 			}
    478 		}
    479 		fp->f_seekp += buf_size;
    480 	}
    481 	return (ENOENT);
    482 }
    483 
    484 #ifdef LIBSA_FFSv2
    485 
    486 daddr_t sblock_try[] = SBLOCKSEARCH;
    487 
    488 static int
    489 ffs_find_superblock(struct open_file *f, struct fs *fs)
    490 {
    491 	int i, rc;
    492 	size_t buf_size;
    493 
    494 	for (i = 0; sblock_try[i] != -1; i++) {
    495 		rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
    496 		    sblock_try[i] / DEV_BSIZE, SBLOCKSIZE, fs, &buf_size);
    497 		if (rc != 0 || buf_size != SBLOCKSIZE)
    498 			return rc;
    499 		if (fs->fs_sblockloc != sblock_try[i])
    500 			/* an alternate superblock - try again */
    501 			continue;
    502 		if (fs->fs_magic == FS_UFS2_MAGIC) {
    503 			return 0;
    504 		}
    505 	}
    506 	return EINVAL;
    507 }
    508 
    509 #endif
    510 
    511 /*
    512  * Open a file.
    513  */
    514 int
    515 ufs_open(const char *path, struct open_file *f)
    516 {
    517 #ifndef LIBSA_FS_SINGLECOMPONENT
    518 	const char *cp, *ncp;
    519 	int c;
    520 #endif
    521 	ino_t inumber;
    522 	struct file *fp;
    523 	struct fs *fs;
    524 	int rc;
    525 #ifndef LIBSA_NO_FS_SYMLINK
    526 	ino_t parent_inumber;
    527 	int nlinks = 0;
    528 	char namebuf[MAXPATHLEN+1];
    529 	char *buf;
    530 #endif
    531 
    532 	/* allocate file system specific data structure */
    533 	fp = alloc(sizeof(struct file));
    534 	memset(fp, 0, sizeof(struct file));
    535 	f->f_fsdata = (void *)fp;
    536 
    537 	/* allocate space and read super block */
    538 	fs = alloc(SBLOCKSIZE);
    539 	fp->f_fs = fs;
    540 	twiddle();
    541 
    542 #ifdef LIBSA_FFSv2
    543 	rc = ffs_find_superblock(f, fs);
    544 	if (rc)
    545 		goto out;
    546 #else
    547 	{
    548 		size_t buf_size;
    549 		rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
    550 			SBLOCKOFFSET / DEV_BSIZE, SBLOCKSIZE, fs, &buf_size);
    551 		if (rc)
    552 			goto out;
    553 		if (buf_size != SBLOCKSIZE ||
    554 #ifdef LIBSA_FFS
    555 		    fs->lfs_version != REQUIRED_LFS_VERSION ||
    556 #endif
    557 		    fs->fs_magic != FS_MAGIC) {
    558 			rc = EINVAL;
    559 			goto out;
    560 		}
    561 	}
    562 #if defined(LIBSA_LFS) && REQUIRED_LFS_VERSION == 2
    563 	/*
    564 	 * XXX	We should check the second superblock and use the eldest
    565 	 *	of the two.  See comments near the top of lfs_mountfs()
    566 	 *	in sys/ufs/lfs/lfs_vfsops.c.
    567 	 *      This may need a LIBSA_LFS_SMALL check as well.
    568 	 */
    569 #endif
    570 #endif
    571 
    572 #ifdef LIBSA_FFSv1
    573 	ffs_oldfscompat(fs);
    574 #endif
    575 
    576 	if (fs->fs_bsize > MAXBSIZE ||
    577 	    (size_t)fs->fs_bsize < sizeof(struct fs)) {
    578 		rc = EINVAL;
    579 		goto out;
    580 	}
    581 
    582 	/*
    583 	 * Calculate indirect block levels.
    584 	 */
    585 	{
    586 		indp_t mult;
    587 		int ln2;
    588 
    589 		/*
    590 		 * We note that the number of indirect blocks is always
    591 		 * a power of 2.  This lets us use shifts and masks instead
    592 		 * of divide and remainder and avoinds pulling in the
    593 		 * 64bit division routine into the boot code.
    594 		 */
    595 		mult = NINDIR(fs);
    596 #ifdef DEBUG
    597 		if (mult & (mult - 1)) {
    598 			/* Hummm was't a power of 2 */
    599 			rc = EINVAL;
    600 			goto out;
    601 		}
    602 #endif
    603 		for (ln2 = 0; mult != 1; ln2++)
    604 			mult >>= 1;
    605 
    606 		fp->f_nishift = ln2;
    607 	}
    608 
    609 	/* alloc a block sized buffer used for all fs transfers */
    610 	fp->f_buf = alloc(fs->fs_bsize);
    611 	inumber = ROOTINO;
    612 	if ((rc = read_inode(inumber, f)) != 0)
    613 		goto out;
    614 
    615 #ifndef LIBSA_FS_SINGLECOMPONENT
    616 	cp = path;
    617 	while (*cp) {
    618 
    619 		/*
    620 		 * Remove extra separators
    621 		 */
    622 		while (*cp == '/')
    623 			cp++;
    624 		if (*cp == '\0')
    625 			break;
    626 
    627 		/*
    628 		 * Check that current node is a directory.
    629 		 */
    630 		if ((fp->f_di.di_mode & IFMT) != IFDIR) {
    631 			rc = ENOTDIR;
    632 			goto out;
    633 		}
    634 
    635 		/*
    636 		 * Get next component of path name.
    637 		 */
    638 		ncp = cp;
    639 		while ((c = *cp) != '\0' && c != '/')
    640 			cp++;
    641 
    642 		/*
    643 		 * Look up component in current directory.
    644 		 * Save directory inumber in case we find a
    645 		 * symbolic link.
    646 		 */
    647 #ifndef LIBSA_NO_FS_SYMLINK
    648 		parent_inumber = inumber;
    649 #endif
    650 		rc = search_directory(ncp, cp - ncp, f, &inumber);
    651 		if (rc)
    652 			goto out;
    653 
    654 		/*
    655 		 * Open next component.
    656 		 */
    657 		if ((rc = read_inode(inumber, f)) != 0)
    658 			goto out;
    659 
    660 #ifndef LIBSA_NO_FS_SYMLINK
    661 		/*
    662 		 * Check for symbolic link.
    663 		 */
    664 		if ((fp->f_di.di_mode & IFMT) == IFLNK) {
    665 			int link_len = fp->f_di.di_size;
    666 			int len;
    667 
    668 			len = strlen(cp);
    669 
    670 			if (link_len + len > MAXPATHLEN ||
    671 			    ++nlinks > MAXSYMLINKS) {
    672 				rc = ENOENT;
    673 				goto out;
    674 			}
    675 
    676 			memmove(&namebuf[link_len], cp, len + 1);
    677 
    678 			if (link_len < fs->fs_maxsymlinklen) {
    679 				memcpy(namebuf, fp->f_di.di_db, link_len);
    680 			} else {
    681 				/*
    682 				 * Read file for symbolic link
    683 				 */
    684 				size_t buf_size;
    685 				indp_t	disk_block;
    686 
    687 				buf = fp->f_buf;
    688 				rc = block_map(f, (indp_t)0, &disk_block);
    689 				if (rc)
    690 					goto out;
    691 
    692 				twiddle();
    693 				rc = DEV_STRATEGY(f->f_dev)(f->f_devdata,
    694 					F_READ, FSBTODB(fs, disk_block),
    695 					fs->fs_bsize, buf, &buf_size);
    696 				if (rc)
    697 					goto out;
    698 
    699 				memcpy(namebuf, buf, link_len);
    700 			}
    701 
    702 			/*
    703 			 * If relative pathname, restart at parent directory.
    704 			 * If absolute pathname, restart at root.
    705 			 */
    706 			cp = namebuf;
    707 			if (*cp != '/')
    708 				inumber = parent_inumber;
    709 			else
    710 				inumber = (ino_t)ROOTINO;
    711 
    712 			if ((rc = read_inode(inumber, f)) != 0)
    713 				goto out;
    714 		}
    715 #endif	/* !LIBSA_NO_FS_SYMLINK */
    716 	}
    717 
    718 	/*
    719 	 * Found terminal component.
    720 	 */
    721 	rc = 0;
    722 
    723 #else /* !LIBSA_FS_SINGLECOMPONENT */
    724 
    725 	/* look up component in the current (root) directory */
    726 	rc = search_directory(path, strlen(path), f, &inumber);
    727 	if (rc)
    728 		goto out;
    729 
    730 	/* open it */
    731 	rc = read_inode(inumber, f);
    732 
    733 #endif /* !LIBSA_FS_SINGLECOMPONENT */
    734 
    735         fp->f_seekp = 0;		/* reset seek pointer */
    736 
    737 out:
    738 	if (rc)
    739 		ufs_close(f);
    740 	return (rc);
    741 }
    742 
    743 int
    744 ufs_close(struct open_file *f)
    745 {
    746 	struct file *fp = (struct file *)f->f_fsdata;
    747 
    748 	f->f_fsdata = NULL;
    749 	if (fp == NULL)
    750 		return (0);
    751 
    752 	if (fp->f_buf)
    753 		free(fp->f_buf, fp->f_fs->fs_bsize);
    754 	free(fp->f_fs, SBLOCKSIZE);
    755 	free(fp, sizeof(struct file));
    756 	return (0);
    757 }
    758 
    759 /*
    760  * Copy a portion of a file into kernel memory.
    761  * Cross block boundaries when necessary.
    762  */
    763 int
    764 ufs_read(struct open_file *f, void *start, size_t size, size_t *resid)
    765 {
    766 	struct file *fp = (struct file *)f->f_fsdata;
    767 	size_t csize;
    768 	char *buf;
    769 	size_t buf_size;
    770 	int rc = 0;
    771 	char *addr = start;
    772 
    773 	while (size != 0) {
    774 		if (fp->f_seekp >= (off_t)fp->f_di.di_size)
    775 			break;
    776 
    777 		rc = buf_read_file(f, &buf, &buf_size);
    778 		if (rc)
    779 			break;
    780 
    781 		csize = size;
    782 		if (csize > buf_size)
    783 			csize = buf_size;
    784 
    785 		memcpy(addr, buf, csize);
    786 
    787 		fp->f_seekp += csize;
    788 		addr += csize;
    789 		size -= csize;
    790 	}
    791 	if (resid)
    792 		*resid = size;
    793 	return (rc);
    794 }
    795 
    796 /*
    797  * Not implemented.
    798  */
    799 #ifndef LIBSA_NO_FS_WRITE
    800 int
    801 ufs_write(struct open_file *f, void *start, size_t size, size_t *resid)
    802 {
    803 
    804 	return (EROFS);
    805 }
    806 #endif /* !LIBSA_NO_FS_WRITE */
    807 
    808 #ifndef LIBSA_NO_FS_SEEK
    809 off_t
    810 ufs_seek(struct open_file *f, off_t offset, int where)
    811 {
    812 	struct file *fp = (struct file *)f->f_fsdata;
    813 
    814 	switch (where) {
    815 	case SEEK_SET:
    816 		fp->f_seekp = offset;
    817 		break;
    818 	case SEEK_CUR:
    819 		fp->f_seekp += offset;
    820 		break;
    821 	case SEEK_END:
    822 		fp->f_seekp = fp->f_di.di_size - offset;
    823 		break;
    824 	default:
    825 		return (-1);
    826 	}
    827 	return (fp->f_seekp);
    828 }
    829 #endif /* !LIBSA_NO_FS_SEEK */
    830 
    831 int
    832 ufs_stat(struct open_file *f, struct stat *sb)
    833 {
    834 	struct file *fp = (struct file *)f->f_fsdata;
    835 
    836 	/* only important stuff */
    837 	memset(sb, 0, sizeof *sb);
    838 	sb->st_mode = fp->f_di.di_mode;
    839 	sb->st_uid = fp->f_di.di_uid;
    840 	sb->st_gid = fp->f_di.di_gid;
    841 	sb->st_size = fp->f_di.di_size;
    842 	return (0);
    843 }
    844 
    845 #ifdef LIBSA_FFSv1
    846 /*
    847  * Sanity checks for old file systems.
    848  *
    849  * XXX - goes away some day.
    850  * Stripped of stuff libsa doesn't need.....
    851  */
    852 static void
    853 ffs_oldfscompat(struct fs *fs)
    854 {
    855 
    856 #ifdef COMPAT_UFS
    857 	if (fs->fs_magic == FS_UFS1_MAGIC &&
    858 	    fs->fs_old_inodefmt < FS_44INODEFMT) {
    859 		fs->fs_qbmask = ~fs->fs_bmask;
    860 		fs->fs_qfmask = ~fs->fs_fmask;
    861 	}
    862 #endif
    863 }
    864 #endif
    865