diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:49:25 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:49:25 +0000 |
commit | 464df1d5e5ab1322e2dd0a7796939fff1aeefa9a (patch) | |
tree | 6a403684e0978f0287d7f0ec0e5aab1fd31a59e1 /lib/ext2fs/imager.c | |
parent | Initial commit. (diff) | |
download | e2fsprogs-upstream/1.47.0.tar.xz e2fsprogs-upstream/1.47.0.zip |
Adding upstream version 1.47.0.upstream/1.47.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | lib/ext2fs/imager.c | 470 |
1 files changed, 470 insertions, 0 deletions
diff --git a/lib/ext2fs/imager.c b/lib/ext2fs/imager.c new file mode 100644 index 0000000..23290a6 --- /dev/null +++ b/lib/ext2fs/imager.c @@ -0,0 +1,470 @@ +/* + * image.c --- writes out the critical parts of the filesystem as a + * flat file. + * + * Copyright (C) 2000 Theodore Ts'o. + * + * Note: this uses the POSIX IO interfaces, unlike most of the other + * functions in this library. So sue me. + * + * %Begin-Header% + * This file may be redistributed under the terms of the GNU Library + * General Public License, version 2. + * %End-Header% + */ + +#include "config.h" +#include <stdio.h> +#include <string.h> +#if HAVE_UNISTD_H +#include <unistd.h> +#endif +#if HAVE_ERRNO_H +#include <errno.h> +#endif +#include <fcntl.h> +#include <time.h> +#if HAVE_SYS_STAT_H +#include <sys/stat.h> +#endif +#if HAVE_SYS_TYPES_H +#include <sys/types.h> +#endif + +#include "ext2_fs.h" +#include "ext2fs.h" + +#ifndef HAVE_TYPE_SSIZE_T +typedef int ssize_t; +#endif + +/* + * This function returns 1 if the specified block is all zeros + */ +static int check_zero_block(char *buf, int blocksize) +{ + char *cp = buf; + int left = blocksize; + + while (left > 0) { + if (*cp++) + return 0; + left--; + } + return 1; +} + +/* + * Write the inode table out as a single block. + */ +#define BUF_BLOCKS 32 + +errcode_t ext2fs_image_inode_write(ext2_filsys fs, int fd, int flags) +{ + dgrp_t group; + ssize_t left, c, d; + char *buf, *cp; + blk64_t blk; + ssize_t actual; + errcode_t retval; + ext2_loff_t r; + + buf = malloc(fs->blocksize * BUF_BLOCKS); + if (!buf) + return ENOMEM; + + for (group = 0; group < fs->group_desc_count; group++) { + blk = ext2fs_inode_table_loc(fs, group); + if (!blk) { + retval = EXT2_ET_MISSING_INODE_TABLE; + goto errout; + } + left = fs->inode_blocks_per_group; + if ((blk < fs->super->s_first_data_block) || + (blk + left - 1 >= ext2fs_blocks_count(fs->super))) { + retval = EXT2_ET_GDESC_BAD_INODE_TABLE; + goto errout; + } + while (left) { + c = BUF_BLOCKS; + if (c > left) + c = left; + retval = io_channel_read_blk64(fs->io, blk, c, buf); + if (retval) + goto errout; + cp = buf; + while (c) { + if (!(flags & IMAGER_FLAG_SPARSEWRITE)) { + d = c; + goto skip_sparse; + } + /* Skip zero blocks */ + if (check_zero_block(cp, fs->blocksize)) { + c--; + blk++; + left--; + cp += fs->blocksize; + r = ext2fs_llseek(fd, fs->blocksize, + SEEK_CUR); + if (r < 0) { + retval = errno; + goto errout; + } + continue; + } + /* Find non-zero blocks */ + for (d = 1; d < c; d++) { + if (check_zero_block(cp + + d * fs->blocksize, + fs->blocksize)) + break; + } + skip_sparse: + actual = write(fd, cp, d * fs->blocksize); + if (actual == -1) { + retval = errno; + goto errout; + } + if (actual != d * fs->blocksize) { + retval = EXT2_ET_SHORT_WRITE; + goto errout; + } + blk += d; + left -= d; + cp += d * fs->blocksize; + c -= d; + } + } + } + retval = 0; + +errout: + free(buf); + return retval; +} + +/* + * Read in the inode table and stuff it into place + */ +errcode_t ext2fs_image_inode_read(ext2_filsys fs, int fd, + int flags EXT2FS_ATTR((unused))) +{ + dgrp_t group; + ssize_t c, left; + char *buf; + blk64_t blk; + ssize_t actual; + errcode_t retval; + + buf = malloc(fs->blocksize * BUF_BLOCKS); + if (!buf) + return ENOMEM; + + for (group = 0; group < fs->group_desc_count; group++) { + blk = ext2fs_inode_table_loc(fs, group); + if (!blk) { + retval = EXT2_ET_MISSING_INODE_TABLE; + goto errout; + } + left = fs->inode_blocks_per_group; + while (left) { + c = BUF_BLOCKS; + if (c > left) + c = left; + actual = read(fd, buf, fs->blocksize * c); + if (actual == -1) { + retval = errno; + goto errout; + } + if (actual != fs->blocksize * c) { + retval = EXT2_ET_SHORT_READ; + goto errout; + } + retval = io_channel_write_blk64(fs->io, blk, c, buf); + if (retval) + goto errout; + + blk += c; + left -= c; + } + } + retval = ext2fs_flush_icache(fs); + +errout: + free(buf); + return retval; +} + +/* + * Write out superblock and group descriptors + */ +errcode_t ext2fs_image_super_write(ext2_filsys fs, int fd, + int flags EXT2FS_ATTR((unused))) +{ + char *buf, *cp; + ssize_t actual; + errcode_t retval; +#ifdef WORDS_BIGENDIAN + unsigned int groups_per_block; + struct ext2_group_desc *gdp; + int j; +#endif + + if (fs->group_desc == NULL) + return EXT2_ET_NO_GDESC; + + buf = malloc(fs->blocksize); + if (!buf) + return ENOMEM; + + /* + * Write out the superblock + */ + memset(buf, 0, fs->blocksize); +#ifdef WORDS_BIGENDIAN + /* + * We're writing out superblock so let's convert + * it to little endian and then back if needed + */ + ext2fs_swap_super(fs->super); + memcpy(buf, fs->super, SUPERBLOCK_SIZE); + ext2fs_swap_super(fs->super); +#else + memcpy(buf, fs->super, SUPERBLOCK_SIZE); +#endif + actual = write(fd, buf, fs->blocksize); + if (actual == -1) { + retval = errno; + goto errout; + } + if (actual != (ssize_t) fs->blocksize) { + retval = EXT2_ET_SHORT_WRITE; + goto errout; + } + + /* + * Now write out the block group descriptors + */ + + cp = (char *) fs->group_desc; + +#ifdef WORDS_BIGENDIAN + /* + * Convert group descriptors to little endian and back + * if needed + */ + groups_per_block = EXT2_DESC_PER_BLOCK(fs->super); + for (j=0; j < groups_per_block*fs->desc_blocks; j++) { + gdp = ext2fs_group_desc(fs, fs->group_desc, j); + if (gdp) + ext2fs_swap_group_desc2(fs, gdp); + } +#endif + + actual = write(fd, cp, (ssize_t)fs->blocksize * fs->desc_blocks); + + +#ifdef WORDS_BIGENDIAN + groups_per_block = EXT2_DESC_PER_BLOCK(fs->super); + for (j=0; j < groups_per_block*fs->desc_blocks; j++) { + gdp = ext2fs_group_desc(fs, fs->group_desc, j); + if (gdp) + ext2fs_swap_group_desc2(fs, gdp); + } +#endif + + if (actual == -1) { + retval = errno; + goto errout; + } + if (actual != (ssize_t)(fs->blocksize * fs->desc_blocks)) { + retval = EXT2_ET_SHORT_WRITE; + goto errout; + } + + retval = 0; + +errout: + free(buf); + return retval; +} + +/* + * Read the superblock and group descriptors and overwrite them. + */ +errcode_t ext2fs_image_super_read(ext2_filsys fs, int fd, + int flags EXT2FS_ATTR((unused))) +{ + char *buf; + ssize_t actual, size; + errcode_t retval; + + size = (ssize_t)fs->blocksize * (fs->group_desc_count + 1); + buf = malloc(size); + if (!buf) + return ENOMEM; + + /* + * Read it all in. + */ + actual = read(fd, buf, size); + if (actual == -1) { + retval = errno; + goto errout; + } + if (actual != size) { + retval = EXT2_ET_SHORT_READ; + goto errout; + } + + /* + * Now copy in the superblock and group descriptors + */ + memcpy(fs->super, buf, SUPERBLOCK_SIZE); + + memcpy(fs->group_desc, buf + fs->blocksize, + (ssize_t)fs->blocksize * fs->group_desc_count); + + retval = 0; + +errout: + free(buf); + return retval; +} + +/* + * Write the block/inode bitmaps. + */ +errcode_t ext2fs_image_bitmap_write(ext2_filsys fs, int fd, int flags) +{ + ext2fs_generic_bitmap bmap; + errcode_t retval; + ssize_t actual; + size_t c; + __u64 itr, cnt, size, total_size; + char buf[1024]; + + if (flags & IMAGER_FLAG_INODEMAP) { + if (!fs->inode_map) { + retval = ext2fs_read_inode_bitmap(fs); + if (retval) + return retval; + } + bmap = fs->inode_map; + itr = 1; + cnt = (__u64)EXT2_INODES_PER_GROUP(fs->super) * + fs->group_desc_count; + size = (EXT2_INODES_PER_GROUP(fs->super) / 8); + } else { + if (!fs->block_map) { + retval = ext2fs_read_block_bitmap(fs); + if (retval) + return retval; + } + bmap = fs->block_map; + itr = fs->super->s_first_data_block; + cnt = EXT2_GROUPS_TO_CLUSTERS(fs->super, fs->group_desc_count); + size = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8; + } + total_size = size * fs->group_desc_count; + + while (cnt > 0) { + size = sizeof(buf); + if (size > (cnt >> 3)) + size = (cnt >> 3); + if (size == 0) + break; + + retval = ext2fs_get_generic_bmap_range(bmap, itr, + size << 3, buf); + if (retval) + return retval; + + actual = write(fd, buf, size); + if (actual == -1) + return errno; + if (actual != (int) size) + return EXT2_ET_SHORT_READ; + + itr += size << 3; + cnt -= size << 3; + } + + size = total_size % fs->blocksize; + memset(buf, 0, sizeof(buf)); + if (size) { + size = fs->blocksize - size; + while (size) { + c = size; + if (c > (int) sizeof(buf)) + c = sizeof(buf); + actual = write(fd, buf, c); + if (actual < 0) + return errno; + if ((size_t) actual != c) + return EXT2_ET_SHORT_WRITE; + size -= c; + } + } + return 0; +} + + +/* + * Read the block/inode bitmaps. + */ +errcode_t ext2fs_image_bitmap_read(ext2_filsys fs, int fd, int flags) +{ + ext2fs_generic_bitmap bmap; + errcode_t retval; + __u64 itr, cnt; + char buf[1024]; + unsigned int size; + ssize_t actual; + + if (flags & IMAGER_FLAG_INODEMAP) { + if (!fs->inode_map) { + retval = ext2fs_read_inode_bitmap(fs); + if (retval) + return retval; + } + bmap = fs->inode_map; + itr = 1; + cnt = (__u64)EXT2_INODES_PER_GROUP(fs->super) * + fs->group_desc_count; + size = (EXT2_INODES_PER_GROUP(fs->super) / 8); + } else { + if (!fs->block_map) { + retval = ext2fs_read_block_bitmap(fs); + if (retval) + return retval; + } + bmap = fs->block_map; + itr = fs->super->s_first_data_block; + cnt = EXT2_GROUPS_TO_BLOCKS(fs->super, fs->group_desc_count); + size = EXT2_BLOCKS_PER_GROUP(fs->super) / 8; + } + + while (cnt > 0) { + size = sizeof(buf); + if (size > (cnt >> 3)) + size = (cnt >> 3); + if (size == 0) + break; + + actual = read(fd, buf, size); + if (actual == -1) + return errno; + if (actual != (int) size) + return EXT2_ET_SHORT_READ; + + retval = ext2fs_set_generic_bmap_range(bmap, itr, + size << 3, buf); + if (retval) + return retval; + + itr += size << 3; + cnt -= size << 3; + } + return 0; +} |