mirror of
https://github.com/sheumann/hush.git
synced 2024-08-16 09:29:16 +00:00
331 lines
8.7 KiB
C
331 lines
8.7 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* openfs.c --- open an ext2 filesystem
|
|
*
|
|
* Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
|
|
*
|
|
* %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
|
|
#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"
|
|
#include "e2image.h"
|
|
|
|
blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i)
|
|
{
|
|
int bg;
|
|
int has_super = 0;
|
|
int ret_blk;
|
|
|
|
if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
|
|
(i < fs->super->s_first_meta_bg))
|
|
return (group_block + i + 1);
|
|
|
|
bg = (fs->blocksize / sizeof (struct ext2_group_desc)) * i;
|
|
if (ext2fs_bg_has_super(fs, bg))
|
|
has_super = 1;
|
|
ret_blk = (fs->super->s_first_data_block + has_super +
|
|
(bg * fs->super->s_blocks_per_group));
|
|
/*
|
|
* If group_block is not the normal value, we're trying to use
|
|
* the backup group descriptors and superblock --- so use the
|
|
* alternate location of the second block group in the
|
|
* metablock group. Ideally we should be testing each bg
|
|
* descriptor block individually for correctness, but we don't
|
|
* have the infrastructure in place to do that.
|
|
*/
|
|
if (group_block != fs->super->s_first_data_block &&
|
|
((ret_blk + fs->super->s_blocks_per_group) <
|
|
fs->super->s_blocks_count))
|
|
ret_blk += fs->super->s_blocks_per_group;
|
|
return ret_blk;
|
|
}
|
|
|
|
errcode_t ext2fs_open(const char *name, int flags, int superblock,
|
|
unsigned int block_size, io_manager manager,
|
|
ext2_filsys *ret_fs)
|
|
{
|
|
return ext2fs_open2(name, 0, flags, superblock, block_size,
|
|
manager, ret_fs);
|
|
}
|
|
|
|
/*
|
|
* Note: if superblock is non-zero, block-size must also be non-zero.
|
|
* Superblock and block_size can be zero to use the default size.
|
|
*
|
|
* Valid flags for ext2fs_open()
|
|
*
|
|
* EXT2_FLAG_RW - Open the filesystem for read/write.
|
|
* EXT2_FLAG_FORCE - Open the filesystem even if some of the
|
|
* features aren't supported.
|
|
* EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
|
|
*/
|
|
errcode_t ext2fs_open2(const char *name, const char *io_options,
|
|
int flags, int superblock,
|
|
unsigned int block_size, io_manager manager,
|
|
ext2_filsys *ret_fs)
|
|
{
|
|
ext2_filsys fs;
|
|
errcode_t retval;
|
|
unsigned long i;
|
|
int groups_per_block, blocks_per_group;
|
|
blk_t group_block, blk;
|
|
char *dest, *cp;
|
|
#if BB_BIG_ENDIAN
|
|
int j;
|
|
struct ext2_group_desc *gdp;
|
|
#endif
|
|
|
|
EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
|
|
|
|
retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
|
|
if (retval)
|
|
return retval;
|
|
|
|
memset(fs, 0, sizeof(struct struct_ext2_filsys));
|
|
fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
|
|
fs->flags = flags;
|
|
fs->umask = 022;
|
|
retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
|
|
if (retval)
|
|
goto cleanup;
|
|
strcpy(fs->device_name, name);
|
|
cp = strchr(fs->device_name, '?');
|
|
if (!io_options && cp) {
|
|
*cp++ = 0;
|
|
io_options = cp;
|
|
}
|
|
|
|
retval = manager->open(fs->device_name,
|
|
(flags & EXT2_FLAG_RW) ? IO_FLAG_RW : 0,
|
|
&fs->io);
|
|
if (retval)
|
|
goto cleanup;
|
|
if (io_options &&
|
|
(retval = io_channel_set_options(fs->io, io_options)))
|
|
goto cleanup;
|
|
fs->image_io = fs->io;
|
|
fs->io->app_data = fs;
|
|
retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->super);
|
|
if (retval)
|
|
goto cleanup;
|
|
if (flags & EXT2_FLAG_IMAGE_FILE) {
|
|
retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
|
|
&fs->image_header);
|
|
if (retval)
|
|
goto cleanup;
|
|
retval = io_channel_read_blk(fs->io, 0,
|
|
-(int)sizeof(struct ext2_image_hdr),
|
|
fs->image_header);
|
|
if (retval)
|
|
goto cleanup;
|
|
if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
|
|
return EXT2_ET_MAGIC_E2IMAGE;
|
|
superblock = 1;
|
|
block_size = fs->image_header->fs_blocksize;
|
|
}
|
|
|
|
/*
|
|
* If the user specifies a specific block # for the
|
|
* superblock, then he/she must also specify the block size!
|
|
* Otherwise, read the master superblock located at offset
|
|
* SUPERBLOCK_OFFSET from the start of the partition.
|
|
*
|
|
* Note: we only save a backup copy of the superblock if we
|
|
* are reading the superblock from the primary superblock location.
|
|
*/
|
|
if (superblock) {
|
|
if (!block_size) {
|
|
retval = EXT2_ET_INVALID_ARGUMENT;
|
|
goto cleanup;
|
|
}
|
|
io_channel_set_blksize(fs->io, block_size);
|
|
group_block = superblock;
|
|
fs->orig_super = 0;
|
|
} else {
|
|
io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
|
|
superblock = 1;
|
|
group_block = 0;
|
|
retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
|
|
if (retval)
|
|
goto cleanup;
|
|
}
|
|
retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
|
|
fs->super);
|
|
if (retval)
|
|
goto cleanup;
|
|
if (fs->orig_super)
|
|
memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
|
|
|
|
#if BB_BIG_ENDIAN
|
|
if ((fs->super->s_magic == ext2fs_swab16(EXT2_SUPER_MAGIC)) ||
|
|
(fs->flags & EXT2_FLAG_SWAP_BYTES)) {
|
|
fs->flags |= EXT2_FLAG_SWAP_BYTES;
|
|
|
|
ext2fs_swap_super(fs->super);
|
|
}
|
|
#endif
|
|
|
|
if (fs->super->s_magic != EXT2_SUPER_MAGIC) {
|
|
retval = EXT2_ET_BAD_MAGIC;
|
|
goto cleanup;
|
|
}
|
|
if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
|
|
retval = EXT2_ET_REV_TOO_HIGH;
|
|
goto cleanup;
|
|
}
|
|
|
|
/*
|
|
* Check for feature set incompatibility
|
|
*/
|
|
if (!(flags & EXT2_FLAG_FORCE)) {
|
|
if (fs->super->s_feature_incompat &
|
|
~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
|
|
retval = EXT2_ET_UNSUPP_FEATURE;
|
|
goto cleanup;
|
|
}
|
|
if ((flags & EXT2_FLAG_RW) &&
|
|
(fs->super->s_feature_ro_compat &
|
|
~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
|
|
retval = EXT2_ET_RO_UNSUPP_FEATURE;
|
|
goto cleanup;
|
|
}
|
|
if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
|
|
(fs->super->s_feature_incompat &
|
|
EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
|
|
retval = EXT2_ET_UNSUPP_FEATURE;
|
|
goto cleanup;
|
|
}
|
|
}
|
|
|
|
fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
|
|
if (fs->blocksize == 0) {
|
|
retval = EXT2_ET_CORRUPT_SUPERBLOCK;
|
|
goto cleanup;
|
|
}
|
|
fs->fragsize = EXT2_FRAG_SIZE(fs->super);
|
|
fs->inode_blocks_per_group = ((fs->super->s_inodes_per_group *
|
|
EXT2_INODE_SIZE(fs->super) +
|
|
EXT2_BLOCK_SIZE(fs->super) - 1) /
|
|
EXT2_BLOCK_SIZE(fs->super));
|
|
if (block_size) {
|
|
if (block_size != fs->blocksize) {
|
|
retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
|
|
goto cleanup;
|
|
}
|
|
}
|
|
/*
|
|
* Set the blocksize to the filesystem's blocksize.
|
|
*/
|
|
io_channel_set_blksize(fs->io, fs->blocksize);
|
|
|
|
/*
|
|
* If this is an external journal device, don't try to read
|
|
* the group descriptors, because they're not there.
|
|
*/
|
|
if (fs->super->s_feature_incompat &
|
|
EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
|
|
fs->group_desc_count = 0;
|
|
*ret_fs = fs;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Read group descriptors
|
|
*/
|
|
blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
|
|
if (blocks_per_group == 0 ||
|
|
blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
|
|
fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super)) {
|
|
retval = EXT2_ET_CORRUPT_SUPERBLOCK;
|
|
goto cleanup;
|
|
}
|
|
fs->group_desc_count = (fs->super->s_blocks_count -
|
|
fs->super->s_first_data_block +
|
|
blocks_per_group - 1) / blocks_per_group;
|
|
fs->desc_blocks = (fs->group_desc_count +
|
|
EXT2_DESC_PER_BLOCK(fs->super) - 1)
|
|
/ EXT2_DESC_PER_BLOCK(fs->super);
|
|
retval = ext2fs_get_mem(fs->desc_blocks * fs->blocksize,
|
|
&fs->group_desc);
|
|
if (retval)
|
|
goto cleanup;
|
|
if (!group_block)
|
|
group_block = fs->super->s_first_data_block;
|
|
dest = (char *) fs->group_desc;
|
|
groups_per_block = fs->blocksize / sizeof(struct ext2_group_desc);
|
|
for (i=0 ; i < fs->desc_blocks; i++) {
|
|
blk = ext2fs_descriptor_block_loc(fs, group_block, i);
|
|
retval = io_channel_read_blk(fs->io, blk, 1, dest);
|
|
if (retval)
|
|
goto cleanup;
|
|
#if BB_BIG_ENDIAN
|
|
if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
|
|
gdp = (struct ext2_group_desc *) dest;
|
|
for (j=0; j < groups_per_block; j++)
|
|
ext2fs_swap_group_desc(gdp++);
|
|
}
|
|
#endif
|
|
dest += fs->blocksize;
|
|
}
|
|
|
|
*ret_fs = fs;
|
|
return 0;
|
|
cleanup:
|
|
ext2fs_free(fs);
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* Set/get the filesystem data I/O channel.
|
|
*
|
|
* These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
|
|
*/
|
|
errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
|
|
{
|
|
if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
|
|
return EXT2_ET_NOT_IMAGE_FILE;
|
|
if (old_io) {
|
|
*old_io = (fs->image_io == fs->io) ? 0 : fs->io;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
|
|
{
|
|
if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
|
|
return EXT2_ET_NOT_IMAGE_FILE;
|
|
fs->io = new_io ? new_io : fs->image_io;
|
|
return 0;
|
|
}
|
|
|
|
errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
|
|
{
|
|
if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
|
|
return EXT2_ET_NOT_IMAGE_FILE;
|
|
fs->io = fs->image_io = new_io;
|
|
fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
|
|
EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
|
|
fs->flags &= ~EXT2_FLAG_IMAGE_FILE;
|
|
return 0;
|
|
}
|