/*
 * 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;
	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 = 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 = 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 = calloc(aux_info.groups, sizeof(char *));

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

	aux_info.bg_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)
{
#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;
}