FreeBSD-5.3/lib/libstand/ext2fs.c
/*-
* Copyright (c) 1999,2000 Jonathan Lemon <jlemon@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/libstand/ext2fs.c,v 1.5 2004/01/21 20:12:23 jhb Exp $");
/*-
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*
* Copyright (c) 1990, 1991 Carnegie Mellon University
* All Rights Reserved.
*
* Author: David Golub
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
#include <sys/param.h>
#include <sys/time.h>
#include "stand.h"
#include "string.h"
static int ext2fs_open(const char *path, struct open_file *f);
static int ext2fs_close(struct open_file *f);
static int ext2fs_read(struct open_file *f, void *buf,
size_t size, size_t *resid);
static off_t ext2fs_seek(struct open_file *f, off_t offset, int where);
static int ext2fs_stat(struct open_file *f, struct stat *sb);
static int ext2fs_readdir(struct open_file *f, struct dirent *d);
static int dtmap[] = { DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR,
DT_BLK, DT_FIFO, DT_SOCK, DT_LNK };
#define EXTFTODT(x) (x) > sizeof(dtmap) / sizeof(dtmap[0]) ? \
DT_UNKNOWN : dtmap[x]
struct fs_ops ext2fs_fsops = {
"ext2fs",
ext2fs_open,
ext2fs_close,
ext2fs_read,
null_write,
ext2fs_seek,
ext2fs_stat,
ext2fs_readdir
};
#define EXT2_SBSIZE 1024
#define EXT2_SBLOCK (1024 / DEV_BSIZE) /* block offset of superblock */
#define EXT2_MAGIC 0xef53
#define EXT2_ROOTINO 2
#define EXT2_REV0 0 /* original revision of ext2 */
#define EXT2_R0_ISIZE 128 /* inode size */
#define EXT2_R0_FIRSTINO 11 /* first inode */
#define EXT2_MINBSHIFT 10 /* mininum block shift */
#define EXT2_MINFSHIFT 10 /* mininum frag shift */
#define NDADDR 12 /* # of direct blocks */
#define NIADDR 3 /* # of indirect blocks */
/*
* file system block to disk address
*/
#define fsb_to_db(fs, blk) ((blk) << (fs)->fs_fsbtodb)
/*
* inode to block group offset
* inode to block group
* inode to disk address
* inode to block offset
*/
#define ino_to_bgo(fs, ino) (((ino) - 1) % (fs)->fs_ipg)
#define ino_to_bg(fs, ino) (((ino) - 1) / (fs)->fs_ipg)
#define ino_to_db(fs, bg, ino) \
fsb_to_db(fs, ((bg)[ino_to_bg(fs, ino)].bg_inotbl + \
ino_to_bgo(fs, ino) / (fs)->fs_ipb))
#define ino_to_bo(fs, ino) (ino_to_bgo(fs, ino) % (fs)->fs_ipb)
#define nindir(fs) \
((fs)->fs_bsize / sizeof(u_int32_t))
#define lblkno(fs, loc) /* loc / bsize */ \
((loc) >> (fs)->fs_bshift)
#define smalllblktosize(fs, blk) /* blk * bsize */ \
((blk) << (fs)->fs_bshift)
#define blkoff(fs, loc) /* loc % bsize */ \
((loc) & (fs)->fs_bmask)
#define fragroundup(fs, size) /* roundup(size, fsize) */ \
(((size) + (fs)->fs_fmask) & ~(fs)->fs_fmask)
#define dblksize(fs, dip, lbn) \
(((lbn) >= NDADDR || (dip)->di_size >= smalllblktosize(fs, (lbn) + 1)) \
? (fs)->fs_bsize \
: (fragroundup(fs, blkoff(fs, (dip)->di_size))))
/*
* superblock describing ext2fs
*/
struct ext2fs_disk {
u_int32_t fd_inodes; /* # of inodes */
u_int32_t fd_blocks; /* # of blocks */
u_int32_t fd_resblk; /* # of reserved blocks */
u_int32_t fd_freeblk; /* # of free blocks */
u_int32_t fd_freeino; /* # of free inodes */
u_int32_t fd_firstblk; /* first data block */
u_int32_t fd_bsize; /* block size */
u_int32_t fd_fsize; /* frag size */
u_int32_t fd_bpg; /* blocks per group */
u_int32_t fd_fpg; /* frags per group */
u_int32_t fd_ipg; /* inodes per group */
u_int32_t fd_mtime; /* mount time */
u_int32_t fd_wtime; /* write time */
u_int16_t fd_mount; /* # of mounts */
int16_t fd_maxmount; /* max # of mounts */
u_int16_t fd_magic; /* magic number */
u_int16_t fd_state; /* state */
u_int16_t fd_eflag; /* error flags */
u_int16_t fd_mnrrev; /* minor revision */
u_int32_t fd_lastchk; /* last check */
u_int32_t fd_chkintvl; /* maximum check interval */
u_int32_t fd_os; /* os */
u_int32_t fd_revision; /* revision */
u_int16_t fd_uid; /* uid for reserved blocks */
u_int16_t fd_gid; /* gid for reserved blocks */
u_int32_t fd_firstino; /* first non-reserved inode */
u_int16_t fd_isize; /* inode size */
u_int16_t fd_nblkgrp; /* block group # of superblock */
u_int32_t fd_fcompat; /* compatible features */
u_int32_t fd_fincompat; /* incompatible features */
u_int32_t fd_frocompat; /* read-only compatibilties */
u_int8_t fd_uuid[16]; /* volume uuid */
char fd_volname[16]; /* volume name */
char fd_fsmnt[64]; /* name last mounted on */
u_int32_t fd_bitmap; /* compression bitmap */
u_int8_t fd_nblkpa; /* # of blocks to preallocate */
u_int8_t fd_ndblkpa; /* # of dir blocks to preallocate */
};
struct ext2fs_core {
int fc_bsize; /* block size */
int fc_bshift; /* block shift amount */
int fc_bmask; /* block mask */
int fc_fsize; /* frag size */
int fc_fshift; /* frag shift amount */
int fc_fmask; /* frag mask */
int fc_isize; /* inode size */
int fc_imask; /* inode mask */
int fc_firstino; /* first non-reserved inode */
int fc_ipb; /* inodes per block */
int fc_fsbtodb; /* fsb to ds shift */
};
struct ext2fs {
struct ext2fs_disk fs_fd;
char fs_pad[EXT2_SBSIZE - sizeof(struct ext2fs_disk)];
struct ext2fs_core fs_fc;
#define fs_magic fs_fd.fd_magic
#define fs_revision fs_fd.fd_revision
#define fs_blocks fs_fd.fd_blocks
#define fs_firstblk fs_fd.fd_firstblk
#define fs_bpg fs_fd.fd_bpg
#define fs_ipg fs_fd.fd_ipg
#define fs_bsize fs_fc.fc_bsize
#define fs_bshift fs_fc.fc_bshift
#define fs_bmask fs_fc.fc_bmask
#define fs_fsize fs_fc.fc_fsize
#define fs_fshift fs_fc.fc_fshift
#define fs_fmask fs_fc.fc_fmask
#define fs_isize fs_fc.fc_isize
#define fs_imask fs_fc.fc_imask
#define fs_firstino fs_fc.fc_firstino
#define fs_ipb fs_fc.fc_ipb
#define fs_fsbtodb fs_fc.fc_fsbtodb
};
struct ext2blkgrp {
u_int32_t bg_blkmap; /* block bitmap */
u_int32_t bg_inomap; /* inode bitmap */
u_int32_t bg_inotbl; /* inode table */
u_int16_t bg_nfblk; /* # of free blocks */
u_int16_t bg_nfino; /* # of free inodes */
u_int16_t bg_ndirs; /* # of dirs */
char bg_pad[14];
};
struct ext2dinode {
u_int16_t di_mode; /* mode */
u_int16_t di_uid; /* uid */
u_int32_t di_size; /* byte size */
u_int32_t di_atime; /* access time */
u_int32_t di_ctime; /* creation time */
u_int32_t di_mtime; /* modification time */
u_int32_t di_dtime; /* deletion time */
u_int16_t di_gid; /* gid */
u_int16_t di_nlink; /* link count */
u_int32_t di_nblk; /* block count */
u_int32_t di_flags; /* file flags */
u_int32_t di_osdep1; /* os dependent stuff */
u_int32_t di_db[NDADDR]; /* direct blocks */
u_int32_t di_ib[NIADDR]; /* indirect blocks */
u_int32_t di_version; /* version */
u_int32_t di_facl; /* file acl */
u_int32_t di_dacl; /* dir acl */
u_int32_t di_faddr; /* fragment addr */
u_int8_t di_frag; /* fragment number */
u_int8_t di_fsize; /* fragment size */
char di_pad[10];
#define di_shortlink di_db
};
#define EXT2_MAXNAMLEN 255
struct ext2dirent {
u_int32_t d_ino; /* inode */
u_int16_t d_reclen; /* directory entry length */
u_int8_t d_namlen; /* name length */
u_int8_t d_type; /* file type */
char d_name[EXT2_MAXNAMLEN];
};
struct file {
off_t f_seekp; /* seek pointer */
struct ext2fs *f_fs; /* pointer to super-block */
struct ext2blkgrp *f_bg; /* pointer to blkgrp map */
struct ext2dinode f_di; /* copy of on-disk inode */
int f_nindir[NIADDR]; /* number of blocks mapped by
indirect block at level i */
char *f_blk[NIADDR]; /* buffer for indirect block
at level i */
size_t f_blksize[NIADDR]; /* size of buffer */
daddr_t f_blkno[NIADDR]; /* disk address of block in
buffer */
char *f_buf; /* buffer for data block */
size_t f_buf_size; /* size of data block */
daddr_t f_buf_blkno; /* block number of data block */
};
/* forward decls */
static int read_inode(ino_t inumber, struct open_file *f);
static int block_map(struct open_file *f, daddr_t file_block,
daddr_t *disk_block_p);
static int buf_read_file(struct open_file *f, char **buf_p,
size_t *size_p);
static int search_directory(char *name, struct open_file *f,
ino_t *inumber_p);
/*
* Open a file.
*/
static int
ext2fs_open(const char *upath, struct open_file *f)
{
struct file *fp;
struct ext2fs *fs;
size_t buf_size;
ino_t inumber, parent_inumber;
int i, len, groups, bg_per_blk, blkgrps, mult;
int nlinks = 0;
int error = 0;
char *cp, *ncp, *path = NULL, *buf = NULL;
char namebuf[MAXPATHLEN+1];
char c;
/* allocate file system specific data structure */
fp = malloc(sizeof(struct file));
if (fp == NULL)
return (ENOMEM);
bzero(fp, sizeof(struct file));
f->f_fsdata = (void *)fp;
/* allocate space and read super block */
fs = (struct ext2fs *)malloc(sizeof(*fs));
fp->f_fs = fs;
twiddle();
error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
EXT2_SBLOCK, EXT2_SBSIZE, (char *)fs, &buf_size);
if (error)
goto out;
if (buf_size != EXT2_SBSIZE || fs->fs_magic != EXT2_MAGIC) {
error = EINVAL;
goto out;
}
/*
* compute in-core values for the superblock
*/
fs->fs_bshift = EXT2_MINBSHIFT + fs->fs_fd.fd_bsize;
fs->fs_bsize = 1 << fs->fs_bshift;
fs->fs_bmask = fs->fs_bsize - 1;
fs->fs_fshift = EXT2_MINFSHIFT + fs->fs_fd.fd_fsize;
fs->fs_fsize = 1 << fs->fs_fshift;
fs->fs_fmask = fs->fs_fsize - 1;
if (fs->fs_revision == EXT2_REV0) {
fs->fs_isize = EXT2_R0_ISIZE;
fs->fs_firstino = EXT2_R0_FIRSTINO;
} else {
fs->fs_isize = fs->fs_fd.fd_isize;
fs->fs_firstino = fs->fs_fd.fd_firstino;
}
fs->fs_imask = fs->fs_isize - 1;
fs->fs_ipb = fs->fs_bsize / fs->fs_isize;
fs->fs_fsbtodb = (fs->fs_bsize / DEV_BSIZE) - 1;
/*
* we have to load in the "group descriptors" here
*/
groups = howmany(fs->fs_blocks - fs->fs_firstblk, fs->fs_bpg);
bg_per_blk = fs->fs_bsize / sizeof(struct ext2blkgrp);
blkgrps = howmany(groups, bg_per_blk);
len = blkgrps * fs->fs_bsize;
fp->f_bg = malloc(len);
twiddle();
error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
EXT2_SBLOCK + EXT2_SBSIZE / DEV_BSIZE, len,
(char *)fp->f_bg, &buf_size);
if (error)
goto out;
/*
* XXX
* validation of values? (blocksize, descriptors, etc?)
*/
/*
* Calculate indirect block levels.
*/
mult = 1;
for (i = 0; i < NIADDR; i++) {
mult *= nindir(fs);
fp->f_nindir[i] = mult;
}
inumber = EXT2_ROOTINO;
if ((error = read_inode(inumber, f)) != 0)
goto out;
path = strdup(upath);
if (path == NULL) {
error = ENOMEM;
goto out;
}
cp = path;
while (*cp) {
/*
* Remove extra separators
*/
while (*cp == '/')
cp++;
if (*cp == '\0')
break;
/*
* Check that current node is a directory.
*/
if (! S_ISDIR(fp->f_di.di_mode)) {
error = ENOTDIR;
goto out;
}
/*
* Get next component of path name.
*/
len = 0;
ncp = cp;
while ((c = *cp) != '\0' && c != '/') {
if (++len > EXT2_MAXNAMLEN) {
error = ENOENT;
goto out;
}
cp++;
}
*cp = '\0';
/*
* Look up component in current directory.
* Save directory inumber in case we find a
* symbolic link.
*/
parent_inumber = inumber;
error = search_directory(ncp, f, &inumber);
*cp = c;
if (error)
goto out;
/*
* Open next component.
*/
if ((error = read_inode(inumber, f)) != 0)
goto out;
/*
* Check for symbolic link.
*/
if (S_ISLNK(fp->f_di.di_mode)) {
int link_len = fp->f_di.di_size;
int len;
len = strlen(cp);
if (link_len + len > MAXPATHLEN ||
++nlinks > MAXSYMLINKS) {
error = ENOENT;
goto out;
}
bcopy(cp, &namebuf[link_len], len + 1);
if (fp->f_di.di_nblk == 0) {
bcopy(fp->f_di.di_shortlink,
namebuf, link_len);
} else {
/*
* Read file for symbolic link
*/
struct ext2fs *fs = fp->f_fs;
daddr_t disk_block;
size_t buf_size;
if (! buf)
buf = malloc(fs->fs_bsize);
error = block_map(f, (daddr_t)0, &disk_block);
if (error)
goto out;
twiddle();
error = (f->f_dev->dv_strategy)(f->f_devdata,
F_READ, fsb_to_db(fs, disk_block),
fs->fs_bsize, buf, &buf_size);
if (error)
goto out;
bcopy((char *)buf, namebuf, link_len);
}
/*
* If relative pathname, restart at parent directory.
* If absolute pathname, restart at root.
*/
cp = namebuf;
if (*cp != '/')
inumber = parent_inumber;
else
inumber = (ino_t)EXT2_ROOTINO;
if ((error = read_inode(inumber, f)) != 0)
goto out;
}
}
/*
* Found terminal component.
*/
error = 0;
out:
if (buf)
free(buf);
if (path)
free(path);
if (error) {
if (fp->f_buf)
free(fp->f_buf);
free(fp->f_fs);
free(fp);
}
return (error);
}
/*
* Read a new inode into a file structure.
*/
static int
read_inode(ino_t inumber, struct open_file *f)
{
struct file *fp = (struct file *)f->f_fsdata;
struct ext2fs *fs = fp->f_fs;
struct ext2dinode *dp;
char *buf;
size_t rsize;
int level, error = 0;
/*
* Read inode and save it.
*/
buf = malloc(fs->fs_bsize);
twiddle();
error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
ino_to_db(fs, fp->f_bg, inumber), fs->fs_bsize, buf, &rsize);
if (error)
goto out;
if (rsize != fs->fs_bsize) {
error = EIO;
goto out;
}
dp = (struct ext2dinode *)buf;
fp->f_di = dp[ino_to_bo(fs, inumber)];
/* clear out old buffers */
for (level = 0; level < NIADDR; level++)
fp->f_blkno[level] = -1;
fp->f_buf_blkno = -1;
out:
free(buf);
return (error);
}
/*
* Given an offset in a file, find the disk block number that
* contains that block.
*/
static int
block_map(struct open_file *f, daddr_t file_block, daddr_t *disk_block_p)
{
struct file *fp = (struct file *)f->f_fsdata;
struct ext2fs *fs = fp->f_fs;
daddr_t ind_block_num;
int32_t *ind_p;
int idx, level;
int error;
/*
* Index structure of an inode:
*
* di_db[0..NDADDR-1] hold block numbers for blocks
* 0..NDADDR-1
*
* di_ib[0] index block 0 is the single indirect block
* holds block numbers for blocks
* NDADDR .. NDADDR + NINDIR(fs)-1
*
* di_ib[1] index block 1 is the double indirect block
* holds block numbers for INDEX blocks for blocks
* NDADDR + NINDIR(fs) ..
* NDADDR + NINDIR(fs) + NINDIR(fs)**2 - 1
*
* di_ib[2] index block 2 is the triple indirect block
* holds block numbers for double-indirect
* blocks for blocks
* NDADDR + NINDIR(fs) + NINDIR(fs)**2 ..
* NDADDR + NINDIR(fs) + NINDIR(fs)**2
* + NINDIR(fs)**3 - 1
*/
if (file_block < NDADDR) {
/* Direct block. */
*disk_block_p = fp->f_di.di_db[file_block];
return (0);
}
file_block -= NDADDR;
/*
* nindir[0] = NINDIR
* nindir[1] = NINDIR**2
* nindir[2] = NINDIR**3
* etc
*/
for (level = 0; level < NIADDR; level++) {
if (file_block < fp->f_nindir[level])
break;
file_block -= fp->f_nindir[level];
}
if (level == NIADDR) {
/* Block number too high */
return (EFBIG);
}
ind_block_num = fp->f_di.di_ib[level];
for (; level >= 0; level--) {
if (ind_block_num == 0) {
*disk_block_p = 0; /* missing */
return (0);
}
if (fp->f_blkno[level] != ind_block_num) {
if (fp->f_blk[level] == (char *)0)
fp->f_blk[level] =
malloc(fs->fs_bsize);
twiddle();
error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
fsb_to_db(fp->f_fs, ind_block_num), fs->fs_bsize,
fp->f_blk[level], &fp->f_blksize[level]);
if (error)
return (error);
if (fp->f_blksize[level] != fs->fs_bsize)
return (EIO);
fp->f_blkno[level] = ind_block_num;
}
ind_p = (int32_t *)fp->f_blk[level];
if (level > 0) {
idx = file_block / fp->f_nindir[level - 1];
file_block %= fp->f_nindir[level - 1];
} else {
idx = file_block;
}
ind_block_num = ind_p[idx];
}
*disk_block_p = ind_block_num;
return (0);
}
/*
* Read a portion of a file into an internal buffer. Return
* the location in the buffer and the amount in the buffer.
*/
static int
buf_read_file(struct open_file *f, char **buf_p, size_t *size_p)
{
struct file *fp = (struct file *)f->f_fsdata;
struct ext2fs *fs = fp->f_fs;
long off;
daddr_t file_block;
daddr_t disk_block;
size_t block_size;
int error = 0;
off = blkoff(fs, fp->f_seekp);
file_block = lblkno(fs, fp->f_seekp);
block_size = dblksize(fs, &fp->f_di, file_block);
if (file_block != fp->f_buf_blkno) {
error = block_map(f, file_block, &disk_block);
if (error)
goto done;
if (fp->f_buf == (char *)0)
fp->f_buf = malloc(fs->fs_bsize);
if (disk_block == 0) {
bzero(fp->f_buf, block_size);
fp->f_buf_size = block_size;
} else {
twiddle();
error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
fsb_to_db(fs, disk_block), block_size,
fp->f_buf, &fp->f_buf_size);
if (error)
goto done;
}
fp->f_buf_blkno = file_block;
}
/*
* Return address of byte in buffer corresponding to
* offset, and size of remainder of buffer after that
* byte.
*/
*buf_p = fp->f_buf + off;
*size_p = block_size - off;
/*
* But truncate buffer at end of file.
*/
if (*size_p > fp->f_di.di_size - fp->f_seekp)
*size_p = fp->f_di.di_size - fp->f_seekp;
done:
return (error);
}
/*
* Search a directory for a name and return its
* i_number.
*/
static int
search_directory(char *name, struct open_file *f, ino_t *inumber_p)
{
struct file *fp = (struct file *)f->f_fsdata;
struct ext2dirent *dp, *edp;
char *buf;
size_t buf_size;
int namlen, length;
int error;
length = strlen(name);
fp->f_seekp = 0;
while (fp->f_seekp < fp->f_di.di_size) {
error = buf_read_file(f, &buf, &buf_size);
if (error)
return (error);
dp = (struct ext2dirent *)buf;
edp = (struct ext2dirent *)(buf + buf_size);
while (dp < edp) {
if (dp->d_ino == (ino_t)0)
goto next;
namlen = dp->d_namlen;
if (namlen == length &&
strncmp(name, dp->d_name, length) == 0) {
/* found entry */
*inumber_p = dp->d_ino;
return (0);
}
next:
dp = (struct ext2dirent *)((char *)dp + dp->d_reclen);
}
fp->f_seekp += buf_size;
}
return (ENOENT);
}
static int
ext2fs_close(struct open_file *f)
{
struct file *fp = (struct file *)f->f_fsdata;
int level;
f->f_fsdata = (void *)0;
if (fp == (struct file *)0)
return (0);
for (level = 0; level < NIADDR; level++) {
if (fp->f_blk[level])
free(fp->f_blk[level]);
}
if (fp->f_buf)
free(fp->f_buf);
if (fp->f_bg)
free(fp->f_bg);
free(fp->f_fs);
free(fp);
return (0);
}
static int
ext2fs_read(struct open_file *f, void *addr, size_t size, size_t *resid)
{
struct file *fp = (struct file *)f->f_fsdata;
size_t csize, buf_size;
char *buf;
int error = 0;
while (size != 0) {
if (fp->f_seekp >= fp->f_di.di_size)
break;
error = buf_read_file(f, &buf, &buf_size);
if (error)
break;
csize = size;
if (csize > buf_size)
csize = buf_size;
bcopy(buf, addr, csize);
fp->f_seekp += csize;
addr += csize;
size -= csize;
}
if (resid)
*resid = size;
return (error);
}
static off_t
ext2fs_seek(struct open_file *f, off_t offset, int where)
{
struct file *fp = (struct file *)f->f_fsdata;
switch (where) {
case SEEK_SET:
fp->f_seekp = offset;
break;
case SEEK_CUR:
fp->f_seekp += offset;
break;
case SEEK_END:
fp->f_seekp = fp->f_di.di_size - offset;
break;
default:
errno = EINVAL;
return (-1);
}
return (fp->f_seekp);
}
static int
ext2fs_stat(struct open_file *f, struct stat *sb)
{
struct file *fp = (struct file *)f->f_fsdata;
/* only important stuff */
sb->st_mode = fp->f_di.di_mode;
sb->st_uid = fp->f_di.di_uid;
sb->st_gid = fp->f_di.di_gid;
sb->st_size = fp->f_di.di_size;
return (0);
}
static int
ext2fs_readdir(struct open_file *f, struct dirent *d)
{
struct file *fp = (struct file *)f->f_fsdata;
struct ext2dirent *ed;
char *buf;
size_t buf_size;
int error;
/*
* assume that a directory entry will not be split across blocks
*/
again:
if (fp->f_seekp >= fp->f_di.di_size)
return (ENOENT);
error = buf_read_file(f, &buf, &buf_size);
if (error)
return (error);
ed = (struct ext2dirent *)buf;
fp->f_seekp += ed->d_reclen;
if (ed->d_ino == (ino_t)0)
goto again;
d->d_type = EXTFTODT(ed->d_type);
strncpy(d->d_name, ed->d_name, ed->d_namlen);
d->d_name[ed->d_namlen] = '\0';
return (0);
}