diff options
Diffstat (limited to 'lib/libstand/ext2fs.c')
-rw-r--r-- | lib/libstand/ext2fs.c | 906 |
1 files changed, 906 insertions, 0 deletions
diff --git a/lib/libstand/ext2fs.c b/lib/libstand/ext2fs.c new file mode 100644 index 0000000..1bd78e2 --- /dev/null +++ b/lib/libstand/ext2fs.c @@ -0,0 +1,906 @@ +/*- + * 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("$FreeBSD$"); + +/*- + * 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 = (char *)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); +} |