From 1fd98e039d146dcff02a5350f509cabca65fd29c Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Mon, 9 May 2005 22:10:42 +0000 Subject: import ext2fs lib to prep for new e2fsprogs --- e2fsprogs/ext2fs/imager.c | 387 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 387 insertions(+) create mode 100644 e2fsprogs/ext2fs/imager.c (limited to 'e2fsprogs/ext2fs/imager.c') diff --git a/e2fsprogs/ext2fs/imager.c b/e2fsprogs/ext2fs/imager.c new file mode 100644 index 000000000..596fbbebe --- /dev/null +++ b/e2fsprogs/ext2fs/imager.c @@ -0,0 +1,387 @@ +/* + * 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 Public + * License. + * %End-Header% + */ + +#include +#include +#if HAVE_UNISTD_H +#include +#endif +#if HAVE_ERRNO_H +#include +#endif +#include +#include +#if HAVE_SYS_STAT_H +#include +#endif +#if HAVE_SYS_TYPES_H +#include +#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) +{ + unsigned int group, left, c, d; + char *buf, *cp; + blk_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 = fs->group_desc[(unsigned)group].bg_inode_table; + if (!blk) + return EXT2_ET_MISSING_INODE_TABLE; + left = fs->inode_blocks_per_group; + while (left) { + c = BUF_BLOCKS; + if (c > left) + c = left; + retval = io_channel_read_blk(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; + lseek(fd, fs->blocksize, SEEK_CUR); + 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, fs->blocksize * d); + if (actual == -1) { + retval = errno; + goto errout; + } + if (actual != (ssize_t) (fs->blocksize * d)) { + retval = EXT2_ET_SHORT_WRITE; + goto errout; + } + blk += d; + left -= d; + cp += fs->blocksize * d; + 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))) +{ + unsigned int group, c, left; + char *buf; + blk_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 = fs->group_desc[(unsigned)group].bg_inode_table; + 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 != (ssize_t) (fs->blocksize * c)) { + retval = EXT2_ET_SHORT_READ; + goto errout; + } + retval = io_channel_write_blk(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; + + buf = malloc(fs->blocksize); + if (!buf) + return ENOMEM; + + /* + * Write out the superblock + */ + memset(buf, 0, fs->blocksize); + memcpy(buf, fs->super, SUPERBLOCK_SIZE); + 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; + actual = write(fd, cp, fs->blocksize * fs->desc_blocks); + 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 = 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, + 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) +{ + char *ptr; + int c, size; + char zero_buf[1024]; + ssize_t actual; + errcode_t retval; + + if (flags & IMAGER_FLAG_INODEMAP) { + if (!fs->inode_map) { + retval = ext2fs_read_inode_bitmap(fs); + if (retval) + return retval; + } + ptr = fs->inode_map->bitmap; + size = (EXT2_INODES_PER_GROUP(fs->super) / 8); + } else { + if (!fs->block_map) { + retval = ext2fs_read_block_bitmap(fs); + if (retval) + return retval; + } + ptr = fs->block_map->bitmap; + size = EXT2_BLOCKS_PER_GROUP(fs->super) / 8; + } + size = size * fs->group_desc_count; + + actual = write(fd, ptr, size); + if (actual == -1) { + retval = errno; + goto errout; + } + if (actual != size) { + retval = EXT2_ET_SHORT_WRITE; + goto errout; + } + size = size % fs->blocksize; + memset(zero_buf, 0, sizeof(zero_buf)); + if (size) { + size = fs->blocksize - size; + while (size) { + c = size; + if (c > (int) sizeof(zero_buf)) + c = sizeof(zero_buf); + actual = write(fd, zero_buf, c); + if (actual == -1) { + retval = errno; + goto errout; + } + if (actual != c) { + retval = EXT2_ET_SHORT_WRITE; + goto errout; + } + size -= c; + } + } + retval = 0; +errout: + return (retval); +} + + +/* + * Read the block/inode bitmaps. + */ +errcode_t ext2fs_image_bitmap_read(ext2_filsys fs, int fd, int flags) +{ + char *ptr, *buf = 0; + int size; + ssize_t actual; + errcode_t retval; + + if (flags & IMAGER_FLAG_INODEMAP) { + if (!fs->inode_map) { + retval = ext2fs_read_inode_bitmap(fs); + if (retval) + return retval; + } + ptr = fs->inode_map->bitmap; + size = (EXT2_INODES_PER_GROUP(fs->super) / 8); + } else { + if (!fs->block_map) { + retval = ext2fs_read_block_bitmap(fs); + if (retval) + return retval; + } + ptr = fs->block_map->bitmap; + size = EXT2_BLOCKS_PER_GROUP(fs->super) / 8; + } + size = size * fs->group_desc_count; + + buf = malloc(size); + if (!buf) + return ENOMEM; + + actual = read(fd, buf, size); + if (actual == -1) { + retval = errno; + goto errout; + } + if (actual != size) { + retval = EXT2_ET_SHORT_WRITE; + goto errout; + } + memcpy(ptr, buf, size); + + retval = 0; +errout: + if (buf) + free(buf); + return (retval); +} -- cgit v1.2.3