mirror of
https://github.com/sheumann/hush.git
synced 2024-12-23 20:29:42 +00:00
378 lines
7.1 KiB
C
378 lines
7.1 KiB
C
|
/* vi: set sw=4 ts=4: */
|
||
|
/*
|
||
|
* 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 <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)
|
||
|
{
|
||
|
unsigned int group, left, c, d;
|
||
|
char *buf, *cp;
|
||
|
blk_t blk;
|
||
|
ssize_t actual;
|
||
|
errcode_t retval;
|
||
|
|
||
|
buf = xmalloc(fs->blocksize * BUF_BLOCKS);
|
||
|
|
||
|
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 = xmalloc(fs->blocksize * BUF_BLOCKS);
|
||
|
|
||
|
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 = xmalloc(fs->blocksize);
|
||
|
|
||
|
/*
|
||
|
* 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 = xmalloc(size);
|
||
|
|
||
|
/*
|
||
|
* 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 = xmalloc(size);
|
||
|
|
||
|
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:
|
||
|
free(buf);
|
||
|
return retval;
|
||
|
}
|