ext4_utils/ext4_utils.cpp - platform/system/extras - Git at Google

 /*
  * Copyright (C) 2010 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "ext4_utils/ext4_utils.h"

 #include <fcntl.h>
 #include <inttypes.h>
 #include <stddef.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>

 #ifdef _WIN32
 #include <winsock2.h>
 #else
 #include <arpa/inet.h>
 #include <sys/ioctl.h>
 #endif

 #if defined(__linux__)
 #include <linux/fs.h>
 #elif defined(__APPLE__) && defined(__MACH__)
 #include <sys/disk.h>
 #endif

 int force = 0;
 struct fs_info info;
 struct fs_aux_info aux_info;

 jmp_buf setjmp_env;

 /* returns 1 if a is a power of b */
 static int is_power_of(int a, int b)
 {
 	while (a > b) {
 		if (a % b)
 			return 0;
 		a /= b;
 	}

 	return (a == b) ? 1 : 0;
 }

 int bitmap_get_bit(u8 *bitmap, u32 bit)
 {
 	if (bitmap[bit / 8] & (1 << (bit % 8)))
 		return 1;

 	return 0;
 }

 void bitmap_clear_bit(u8 *bitmap, u32 bit)
 {
 	bitmap[bit / 8] &= ~(1 << (bit % 8));

 	return;
 }

 /* Returns 1 if the bg contains a backup superblock.  On filesystems with
    the sparse_super feature, only block groups 0, 1, and powers of 3, 5,
    and 7 have backup superblocks.  Otherwise, all block groups have backup
    superblocks */
 int ext4_bg_has_super_block(int bg)
 {
 	/* Without sparse_super, every block group has a superblock */
 	if (!(info.feat_ro_compat & EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER))
 		return 1;

 	if (bg == 0 || bg == 1)
 		return 1;

 	if (is_power_of(bg, 3) || is_power_of(bg, 5) || is_power_of(bg, 7))
 		return 1;

 	return 0;
 }

 /* Function to read the primary superblock */
 void read_sb(int fd, struct ext4_super_block *sb)
 {
 	off64_t ret;

 	ret = lseek64(fd, 1024, SEEK_SET);
 	if (ret < 0)
 		critical_error_errno("failed to seek to superblock");

 	ret = read(fd, sb, sizeof(*sb));
 	if (ret < 0)
 		critical_error_errno("failed to read superblock");
 	if (ret != sizeof(*sb))
 		critical_error("failed to read all of superblock");
 }

 /* Compute the rest of the parameters of the filesystem from the basic info */
 void ext4_create_fs_aux_info()
 {
 	aux_info.first_data_block = (info.block_size > 1024) ? 0 : 1;
 	aux_info.len_blocks = info.len / info.block_size;
 	aux_info.inode_table_blocks = DIV_ROUND_UP(info.inodes_per_group * info.inode_size,
 		info.block_size);
 	aux_info.groups = DIV_ROUND_UP(aux_info.len_blocks - aux_info.first_data_block,
 		info.blocks_per_group);
 	aux_info.blocks_per_ind = info.block_size / sizeof(u32);
 	aux_info.blocks_per_dind = aux_info.blocks_per_ind * aux_info.blocks_per_ind;
 	aux_info.blocks_per_tind = aux_info.blocks_per_dind * aux_info.blocks_per_dind;

 	aux_info.bg_desc_blocks =
 		DIV_ROUND_UP(aux_info.groups * sizeof(struct ext2_group_desc),
 			info.block_size);

 	aux_info.default_i_flags = EXT4_NOATIME_FL;

 	u32 last_group_size = aux_info.len_blocks == info.blocks_per_group
 		? aux_info.len_blocks : aux_info.len_blocks % info.blocks_per_group;
 	u32 last_header_size = 2 + aux_info.inode_table_blocks;
 	if (ext4_bg_has_super_block((int)aux_info.groups - 1))
 		last_header_size += 1 + aux_info.bg_desc_blocks +
 			info.bg_desc_reserve_blocks;
 	if (aux_info.groups <= 1 && last_group_size < last_header_size) {
 		critical_error("filesystem size too small");
 	}
 	if (last_group_size > 0 && last_group_size < last_header_size) {
 		aux_info.groups--;
 		aux_info.len_blocks -= last_group_size;
 	}

 	/* A zero-filled superblock to be written firstly to the block
 	 * device to mark the file-system as invalid
 	 */
 	aux_info.sb_zero = (struct ext4_super_block *)calloc(1, info.block_size);
 	if (!aux_info.sb_zero)
 		critical_error_errno("calloc");

 	/* The write_data* functions expect only block aligned calls.
 	 * This is not an issue, except when we write out the super
 	 * block on a system with a block size > 1K.  So, we need to
 	 * deal with that here.
 	 */
 	aux_info.sb_block = (struct ext4_super_block *)calloc(1, info.block_size);
 	if (!aux_info.sb_block)
 		critical_error_errno("calloc");

 	if (info.block_size > 1024)
 		aux_info.sb = (struct ext4_super_block *)((char *)aux_info.sb_block + 1024);
 	else
 		aux_info.sb = aux_info.sb_block;

 	/* Alloc an array to hold the pointers to the backup superblocks */
 	aux_info.backup_sb = (struct ext4_super_block **)calloc(aux_info.groups, sizeof(char *));

 	if (!aux_info.sb)
 		critical_error_errno("calloc");

 	aux_info.bg_desc = (struct ext2_group_desc *)calloc(info.block_size, aux_info.bg_desc_blocks);
 	if (!aux_info.bg_desc)
 		critical_error_errno("calloc");
 	aux_info.xattrs = NULL;
 }

 void ext4_free_fs_aux_info()
 {
 	unsigned int i;

 	for (i=0; i<aux_info.groups; i++) {
 		if (aux_info.backup_sb[i])
 			free(aux_info.backup_sb[i]);
 	}
 	free(aux_info.sb_block);
 	free(aux_info.sb_zero);
 	free(aux_info.bg_desc);
 }

 void ext4_parse_sb_info(struct ext4_super_block *sb)
 {
 	if (sb->s_magic != EXT4_SUPER_MAGIC)
 		error("superblock magic incorrect");

 	if ((sb->s_state & EXT4_VALID_FS) != EXT4_VALID_FS)
 		error("filesystem state not valid");

 	ext4_parse_sb(sb, &info);

 	ext4_create_fs_aux_info();

 	memcpy(aux_info.sb, sb, sizeof(*sb));

 	if (aux_info.first_data_block != sb->s_first_data_block)
 		critical_error("first data block does not match");
 }

 u64 get_block_device_size(int fd)
 {
 	u64 size = 0;
 	int ret;

 #if defined(__linux__)
 	ret = ioctl(fd, BLKGETSIZE64, &size);
 #elif defined(__APPLE__) && defined(__MACH__)
 	ret = ioctl(fd, DKIOCGETBLOCKCOUNT, &size);
 #else
 	close(fd);
 	return 0;
 #endif

 	if (ret)
 		return 0;

 	return size;
 }

 int is_block_device_fd(int fd __attribute__((unused)))
 {
 #ifdef _WIN32
 	return 0;
 #else
 	struct stat st;
 	int ret = fstat(fd, &st);
 	if (ret < 0)
 		return 0;

 	return S_ISBLK(st.st_mode);
 #endif
 }

 u64 get_file_size(int fd)
 {
 	struct stat buf;
 	int ret;
 	u64 reserve_len = 0;
 	s64 computed_size;

 	ret = fstat(fd, &buf);
 	if (ret)
 		return 0;

 	if (info.len < 0)
 		reserve_len = -info.len;

 	if (S_ISREG(buf.st_mode))
 		computed_size = buf.st_size - reserve_len;
 	else if (S_ISBLK(buf.st_mode))
 		computed_size = get_block_device_size(fd) - reserve_len;
 	else
 		computed_size = 0;

 	if (computed_size < 0) {
 		warn("Computed filesystem size less than 0");
 		computed_size = 0;
 	}

 	return computed_size;
 }

 int read_ext(int fd, int verbose)
 {
 	off64_t ret;
 	struct ext4_super_block sb;

 	read_sb(fd, &sb);

 	ext4_parse_sb_info(&sb);

 	ret = lseek64(fd, info.len, SEEK_SET);
 	if (ret < 0)
 		critical_error_errno("failed to seek to end of input image");

 	ret = lseek64(fd, info.block_size * (aux_info.first_data_block + 1), SEEK_SET);
 	if (ret < 0)
 		critical_error_errno("failed to seek to block group descriptors");

 	ret = read(fd, aux_info.bg_desc, info.block_size * aux_info.bg_desc_blocks);
 	if (ret < 0)
 		critical_error_errno("failed to read block group descriptors");
 	if (ret != (int)info.block_size * (int)aux_info.bg_desc_blocks)
 		critical_error("failed to read all of block group descriptors");

 	if (verbose) {
 		printf("Found filesystem with parameters:\n");
 		printf("    Size: %" PRIu64 "\n", info.len);
 		printf("    Block size: %d\n", info.block_size);
 		printf("    Blocks per group: %d\n", info.blocks_per_group);
 		printf("    Inodes per group: %d\n", info.inodes_per_group);
 		printf("    Inode size: %d\n", info.inode_size);
 		printf("    Label: %s\n", info.label);
 		printf("    Blocks: %" PRIext4u64 "\n", aux_info.len_blocks);
 		printf("    Block groups: %d\n", aux_info.groups);
 		printf("    Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
 		printf("    Used %d/%d inodes and %d/%d blocks\n",
 			aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
 			aux_info.sb->s_inodes_count,
 			aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
 			aux_info.sb->s_blocks_count_lo);
 	}

 	return 0;
 }
	/*
	* Copyright (C) 2010 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "ext4_utils/ext4_utils.h"

	#include <fcntl.h>
	#include <inttypes.h>
	#include <stddef.h>
	#include <string.h>
	#include <sys/stat.h>
	#include <sys/types.h>

	#ifdef _WIN32
	#include <winsock2.h>
	#else
	#include <arpa/inet.h>
	#include <sys/ioctl.h>
	#endif

	#if defined(__linux__)
	#include <linux/fs.h>
	#elif defined(__APPLE__) && defined(__MACH__)
	#include <sys/disk.h>
	#endif

	int force = 0;
	struct fs_info info;
	struct fs_aux_info aux_info;

	jmp_buf setjmp_env;

	/* returns 1 if a is a power of b */
	static int is_power_of(int a, int b)
	{
	while (a > b) {
	if (a % b)
	return 0;
	a /= b;
	}

	return (a == b) ? 1 : 0;
	}

	int bitmap_get_bit(u8 *bitmap, u32 bit)
	{
	if (bitmap[bit / 8] & (1 << (bit % 8)))
	return 1;

	return 0;
	}

	void bitmap_clear_bit(u8 *bitmap, u32 bit)
	{
	bitmap[bit / 8] &= ~(1 << (bit % 8));

	return;
	}

	/* Returns 1 if the bg contains a backup superblock. On filesystems with
	the sparse_super feature, only block groups 0, 1, and powers of 3, 5,
	and 7 have backup superblocks. Otherwise, all block groups have backup
	superblocks */
	int ext4_bg_has_super_block(int bg)
	{
	/* Without sparse_super, every block group has a superblock */
	if (!(info.feat_ro_compat & EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER))
	return 1;

	if (bg == 0 \|\| bg == 1)
	return 1;

	if (is_power_of(bg, 3) \|\| is_power_of(bg, 5) \|\| is_power_of(bg, 7))
	return 1;

	return 0;
	}

	/* Function to read the primary superblock */
	void read_sb(int fd, struct ext4_super_block *sb)
	{
	off64_t ret;

	ret = lseek64(fd, 1024, SEEK_SET);
	if (ret < 0)
	critical_error_errno("failed to seek to superblock");

	ret = read(fd, sb, sizeof(*sb));
	if (ret < 0)
	critical_error_errno("failed to read superblock");
	if (ret != sizeof(*sb))
	critical_error("failed to read all of superblock");
	}

	/* Compute the rest of the parameters of the filesystem from the basic info */
	void ext4_create_fs_aux_info()
	{
	aux_info.first_data_block = (info.block_size > 1024) ? 0 : 1;
	aux_info.len_blocks = info.len / info.block_size;
	aux_info.inode_table_blocks = DIV_ROUND_UP(info.inodes_per_group * info.inode_size,
	info.block_size);
	aux_info.groups = DIV_ROUND_UP(aux_info.len_blocks - aux_info.first_data_block,
	info.blocks_per_group);
	aux_info.blocks_per_ind = info.block_size / sizeof(u32);
	aux_info.blocks_per_dind = aux_info.blocks_per_ind * aux_info.blocks_per_ind;
	aux_info.blocks_per_tind = aux_info.blocks_per_dind * aux_info.blocks_per_dind;

	aux_info.bg_desc_blocks =
	DIV_ROUND_UP(aux_info.groups * sizeof(struct ext2_group_desc),
	info.block_size);

	aux_info.default_i_flags = EXT4_NOATIME_FL;

	u32 last_group_size = aux_info.len_blocks == info.blocks_per_group
	? aux_info.len_blocks : aux_info.len_blocks % info.blocks_per_group;
	u32 last_header_size = 2 + aux_info.inode_table_blocks;
	if (ext4_bg_has_super_block((int)aux_info.groups - 1))
	last_header_size += 1 + aux_info.bg_desc_blocks +
	info.bg_desc_reserve_blocks;
	if (aux_info.groups <= 1 && last_group_size < last_header_size) {
	critical_error("filesystem size too small");
	}
	if (last_group_size > 0 && last_group_size < last_header_size) {
	aux_info.groups--;
	aux_info.len_blocks -= last_group_size;
	}

	/* A zero-filled superblock to be written firstly to the block
	* device to mark the file-system as invalid
	*/
	aux_info.sb_zero = (struct ext4_super_block *)calloc(1, info.block_size);
	if (!aux_info.sb_zero)
	critical_error_errno("calloc");

	/* The write_data* functions expect only block aligned calls.
	* This is not an issue, except when we write out the super
	* block on a system with a block size > 1K. So, we need to
	* deal with that here.
	*/
	aux_info.sb_block = (struct ext4_super_block *)calloc(1, info.block_size);
	if (!aux_info.sb_block)
	critical_error_errno("calloc");

	if (info.block_size > 1024)
	aux_info.sb = (struct ext4_super_block )((char )aux_info.sb_block + 1024);
	else
	aux_info.sb = aux_info.sb_block;

	/* Alloc an array to hold the pointers to the backup superblocks */
	aux_info.backup_sb = (struct ext4_super_block *)calloc(aux_info.groups, sizeof(char ));

	if (!aux_info.sb)
	critical_error_errno("calloc");

	aux_info.bg_desc = (struct ext2_group_desc *)calloc(info.block_size, aux_info.bg_desc_blocks);
	if (!aux_info.bg_desc)
	critical_error_errno("calloc");
	aux_info.xattrs = NULL;
	}

	void ext4_free_fs_aux_info()
	{
	unsigned int i;

	for (i=0; i<aux_info.groups; i++) {
	if (aux_info.backup_sb[i])
	free(aux_info.backup_sb[i]);
	}
	free(aux_info.sb_block);
	free(aux_info.sb_zero);
	free(aux_info.bg_desc);
	}

	void ext4_parse_sb_info(struct ext4_super_block *sb)
	{
	if (sb->s_magic != EXT4_SUPER_MAGIC)
	error("superblock magic incorrect");

	if ((sb->s_state & EXT4_VALID_FS) != EXT4_VALID_FS)
	error("filesystem state not valid");

	ext4_parse_sb(sb, &info);

	ext4_create_fs_aux_info();

	memcpy(aux_info.sb, sb, sizeof(*sb));

	if (aux_info.first_data_block != sb->s_first_data_block)
	critical_error("first data block does not match");
	}

	u64 get_block_device_size(int fd)
	{
	u64 size = 0;
	int ret;

	#if defined(__linux__)
	ret = ioctl(fd, BLKGETSIZE64, &size);
	#elif defined(__APPLE__) && defined(__MACH__)
	ret = ioctl(fd, DKIOCGETBLOCKCOUNT, &size);
	#else
	close(fd);
	return 0;
	#endif

	if (ret)
	return 0;

	return size;
	}

	int is_block_device_fd(int fd __attribute__((unused)))
	{
	#ifdef _WIN32
	return 0;
	#else
	struct stat st;
	int ret = fstat(fd, &st);
	if (ret < 0)
	return 0;

	return S_ISBLK(st.st_mode);
	#endif
	}

	u64 get_file_size(int fd)
	{
	struct stat buf;
	int ret;
	u64 reserve_len = 0;
	s64 computed_size;

	ret = fstat(fd, &buf);
	if (ret)
	return 0;

	if (info.len < 0)
	reserve_len = -info.len;

	if (S_ISREG(buf.st_mode))
	computed_size = buf.st_size - reserve_len;
	else if (S_ISBLK(buf.st_mode))
	computed_size = get_block_device_size(fd) - reserve_len;
	else
	computed_size = 0;

	if (computed_size < 0) {
	warn("Computed filesystem size less than 0");
	computed_size = 0;
	}

	return computed_size;
	}

	int read_ext(int fd, int verbose)
	{
	off64_t ret;
	struct ext4_super_block sb;

	read_sb(fd, &sb);

	ext4_parse_sb_info(&sb);

	ret = lseek64(fd, info.len, SEEK_SET);
	if (ret < 0)
	critical_error_errno("failed to seek to end of input image");

	ret = lseek64(fd, info.block_size * (aux_info.first_data_block + 1), SEEK_SET);
	if (ret < 0)
	critical_error_errno("failed to seek to block group descriptors");

	ret = read(fd, aux_info.bg_desc, info.block_size * aux_info.bg_desc_blocks);
	if (ret < 0)
	critical_error_errno("failed to read block group descriptors");
	if (ret != (int)info.block_size * (int)aux_info.bg_desc_blocks)
	critical_error("failed to read all of block group descriptors");

	if (verbose) {
	printf("Found filesystem with parameters:\n");
	printf(" Size: %" PRIu64 "\n", info.len);
	printf(" Block size: %d\n", info.block_size);
	printf(" Blocks per group: %d\n", info.blocks_per_group);
	printf(" Inodes per group: %d\n", info.inodes_per_group);
	printf(" Inode size: %d\n", info.inode_size);
	printf(" Label: %s\n", info.label);
	printf(" Blocks: %" PRIext4u64 "\n", aux_info.len_blocks);
	printf(" Block groups: %d\n", aux_info.groups);
	printf(" Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
	printf(" Used %d/%d inodes and %d/%d blocks\n",
	aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
	aux_info.sb->s_inodes_count,
	aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
	aux_info.sb->s_blocks_count_lo);
	}

	return 0;
	}