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-rw-r--r--lib/ext2fs/imager.c470
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;
+}
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