ext4_utils/output_file.c - 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.h"
 #include "output_file.h"
 #include "sparse_format.h"
 #include "sparse_crc32.h"
 #include "wipe.h"

 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/mman.h>
 #include <unistd.h>
 #include <fcntl.h>

 #include <zlib.h>

 #if defined(__APPLE__) && defined(__MACH__)
 #define lseek64 lseek
 #define off64_t off_t
 #endif

 #define SPARSE_HEADER_MAJOR_VER 1
 #define SPARSE_HEADER_MINOR_VER 0
 #define SPARSE_HEADER_LEN       (sizeof(sparse_header_t))
 #define CHUNK_HEADER_LEN (sizeof(chunk_header_t))

 struct output_file_ops {
 	int (*seek)(struct output_file *, off64_t);
 	int (*write)(struct output_file *, u8 *, int);
 	void (*close)(struct output_file *);
 };

 struct output_file {
 	int fd;
 	gzFile gz_fd;
 	int sparse;
 	u64 cur_out_ptr;
 	u32 chunk_cnt;
 	u32 crc32;
 	struct output_file_ops *ops;
 	int use_crc;
 };

 static int file_seek(struct output_file *out, off64_t off)
 {
 	off64_t ret;

 	ret = lseek64(out->fd, off, SEEK_SET);
 	if (ret < 0) {
 		error_errno("lseek64");
 		return -1;
 	}
 	return 0;
 }

 static int file_write(struct output_file *out, u8 *data, int len)
 {
 	int ret;
 	ret = write(out->fd, data, len);
 	if (ret < 0) {
 		error_errno("write");
 		return -1;
 	} else if (ret < len) {
 		error("incomplete write");
 		return -1;
 	}

 	return 0;
 }

 static void file_close(struct output_file *out)
 {
 	close(out->fd);
 }


 static struct output_file_ops file_ops = {
 	.seek = file_seek,
 	.write = file_write,
 	.close = file_close,
 };

 static int gz_file_seek(struct output_file *out, off64_t off)
 {
 	off64_t ret;

 	ret = gzseek(out->gz_fd, off, SEEK_SET);
 	if (ret < 0) {
 		error_errno("gzseek");
 		return -1;
 	}
 	return 0;
 }

 static int gz_file_write(struct output_file *out, u8 *data, int len)
 {
 	int ret;
 	ret = gzwrite(out->gz_fd, data, len);
 	if (ret < 0) {
 		error_errno("gzwrite");
 		return -1;
 	} else if (ret < len) {
 		error("incomplete gzwrite");
 		return -1;
 	}

 	return 0;
 }

 static void gz_file_close(struct output_file *out)
 {
 	gzclose(out->gz_fd);
 }

 static struct output_file_ops gz_file_ops = {
 	.seek = gz_file_seek,
 	.write = gz_file_write,
 	.close = gz_file_close,
 };

 static sparse_header_t sparse_header = {
 	.magic = SPARSE_HEADER_MAGIC,
 	.major_version = SPARSE_HEADER_MAJOR_VER,
 	.minor_version = SPARSE_HEADER_MINOR_VER,
 	.file_hdr_sz = SPARSE_HEADER_LEN,
 	.chunk_hdr_sz = CHUNK_HEADER_LEN,
 	.blk_sz = 0,
 	.total_blks = 0,
 	.total_chunks = 0,
 	.image_checksum = 0
 };

 static u8 *zero_buf;

 static int emit_skip_chunk(struct output_file *out, u64 skip_len)
 {
 	chunk_header_t chunk_header;
 	int ret, chunk;

 	//DBG printf("skip chunk: 0x%llx bytes\n", skip_len);

 	if (skip_len % info.block_size) {
 		error("don't care size %llu is not a multiple of the block size %u",
 				skip_len, info.block_size);
 		return -1;
 	}

 	/* We are skipping data, so emit a don't care chunk. */
 	chunk_header.chunk_type = CHUNK_TYPE_DONT_CARE;
 	chunk_header.reserved1 = 0;
 	chunk_header.chunk_sz = skip_len / info.block_size;
 	chunk_header.total_sz = CHUNK_HEADER_LEN;
 	ret = out->ops->write(out, (u8 *)&chunk_header, sizeof(chunk_header));
 	if (ret < 0)
 		return -1;

 	out->cur_out_ptr += skip_len;
 	out->chunk_cnt++;

 	return 0;
 }

 static int write_chunk_fill(struct output_file *out, u64 off, u32 fill_val, int len)
 {
 	chunk_header_t chunk_header;
 	int rnd_up_len, zero_len, count;
 	int ret;
 	unsigned int i;
 	u32 fill_buf[4096/sizeof(u32)]; /* Maximum size of a block */

 	/* We can assume that all the chunks to be written are in
 	 * ascending order, block-size aligned, and non-overlapping.
 	 * So, if the offset is less than the current output pointer,
 	 * throw an error, and if there is a gap, emit a "don't care"
 	 * chunk.  The first write (of the super block) may not be
 	 * blocksize aligned, so we need to deal with that too.
 	 */
 	//DBG printf("write chunk: offset 0x%llx, length 0x%x bytes\n", off, len);

 	if (off < out->cur_out_ptr) {
 		error("offset %llu is less than the current output offset %llu",
 				off, out->cur_out_ptr);
 		return -1;
 	}

 	if (off > out->cur_out_ptr) {
 		emit_skip_chunk(out, off - out->cur_out_ptr);
 	}

 	if (off % info.block_size) {
 		error("write chunk offset %llu is not a multiple of the block size %u",
 				off, info.block_size);
 		return -1;
 	}

 	if (off != out->cur_out_ptr) {
 		error("internal error, offset accounting screwy in write_chunk_raw()");
 		return -1;
 	}

 	/* Round up the file length to a multiple of the block size */
 	rnd_up_len = (len + (info.block_size - 1)) & (~(info.block_size -1));

 	/* Finally we can safely emit a chunk of data */
 	chunk_header.chunk_type = CHUNK_TYPE_FILL;
 	chunk_header.reserved1 = 0;
 	chunk_header.chunk_sz = rnd_up_len / info.block_size;
 	chunk_header.total_sz = CHUNK_HEADER_LEN + sizeof(fill_val);
 	ret = out->ops->write(out, (u8 *)&chunk_header, sizeof(chunk_header));

 	if (ret < 0)
 		return -1;
 	ret = out->ops->write(out, (u8 *)&fill_val, sizeof(fill_val));
 	if (ret < 0)
 		return -1;

 	if (out->use_crc) {
                 /* Initialize fill_buf with the fill_val */
 		for (i = 0; i < (info.block_size / sizeof(u32)); i++) {
 			fill_buf[i] = fill_val;
 		}

 		count = chunk_header.chunk_sz;
 		while (count) {
 			out->crc32 = sparse_crc32(out->crc32, fill_buf, info.block_size);
 			count--;
 		}
 	}

 	out->cur_out_ptr += rnd_up_len;
 	out->chunk_cnt++;

 	return 0;
 }

 static int write_chunk_raw(struct output_file *out, u64 off, u8 *data, int len)
 {
 	chunk_header_t chunk_header;
 	int rnd_up_len, zero_len;
 	int ret;

 	/* We can assume that all the chunks to be written are in
 	 * ascending order, block-size aligned, and non-overlapping.
 	 * So, if the offset is less than the current output pointer,
 	 * throw an error, and if there is a gap, emit a "don't care"
 	 * chunk.  The first write (of the super block) may not be
 	 * blocksize aligned, so we need to deal with that too.
 	 */
 	//DBG printf("write chunk: offset 0x%llx, length 0x%x bytes\n", off, len);

 	if (off < out->cur_out_ptr) {
 		error("offset %llu is less than the current output offset %llu",
 				off, out->cur_out_ptr);
 		return -1;
 	}

 	if (off > out->cur_out_ptr) {
 		emit_skip_chunk(out, off - out->cur_out_ptr);
 	}

 	if (off % info.block_size) {
 		error("write chunk offset %llu is not a multiple of the block size %u",
 				off, info.block_size);
 		return -1;
 	}

 	if (off != out->cur_out_ptr) {
 		error("internal error, offset accounting screwy in write_chunk_raw()");
 		return -1;
 	}

 	/* Round up the file length to a multiple of the block size */
 	rnd_up_len = (len + (info.block_size - 1)) & (~(info.block_size -1));
 	zero_len = rnd_up_len - len;

 	/* Finally we can safely emit a chunk of data */
 	chunk_header.chunk_type = CHUNK_TYPE_RAW;
 	chunk_header.reserved1 = 0;
 	chunk_header.chunk_sz = rnd_up_len / info.block_size;
 	chunk_header.total_sz = CHUNK_HEADER_LEN + rnd_up_len;
 	ret = out->ops->write(out, (u8 *)&chunk_header, sizeof(chunk_header));

 	if (ret < 0)
 		return -1;
 	ret = out->ops->write(out, data, len);
 	if (ret < 0)
 		return -1;
 	if (zero_len) {
 		ret = out->ops->write(out, zero_buf, zero_len);
 		if (ret < 0)
 			return -1;
 	}

 	if (out->use_crc) {
 		out->crc32 = sparse_crc32(out->crc32, data, len);
 		if (zero_len)
 			out->crc32 = sparse_crc32(out->crc32, zero_buf, zero_len);
 	}

 	out->cur_out_ptr += rnd_up_len;
 	out->chunk_cnt++;

 	return 0;
 }

 void close_output_file(struct output_file *out)
 {
 	int ret;
 	chunk_header_t chunk_header;

 	if (out->sparse) {
 		if (out->use_crc) {
 			chunk_header.chunk_type = CHUNK_TYPE_CRC32;
 			chunk_header.reserved1 = 0;
 			chunk_header.chunk_sz = 0;
 			chunk_header.total_sz = CHUNK_HEADER_LEN + 4;

 			out->ops->write(out, (u8 *)&chunk_header, sizeof(chunk_header));
 			out->ops->write(out, (u8 *)&out->crc32, 4);

 			out->chunk_cnt++;
 		}

 		if (out->chunk_cnt != sparse_header.total_chunks)
 			error("sparse chunk count did not match: %d %d", out->chunk_cnt,
 					sparse_header.total_chunks);
 	}
 	out->ops->close(out);
 }

 struct output_file *open_output_file(const char *filename, int gz, int sparse,
         int chunks, int crc, int wipe)
 {
 	int ret;
 	struct output_file *out = malloc(sizeof(struct output_file));
 	if (!out) {
 		error_errno("malloc struct out");
 		return NULL;
 	}
 	zero_buf = malloc(info.block_size);
 	if (!zero_buf) {
 		error_errno("malloc zero_buf");
 		free(out);
 		return NULL;
 	}
 	memset(zero_buf, '\0', info.block_size);

 	if (gz) {
 		out->ops = &gz_file_ops;
 		out->gz_fd = gzopen(filename, "wb9");
 		if (!out->gz_fd) {
 			error_errno("gzopen");
 			free(out);
 			return NULL;
 		}
 	} else {
 		if (strcmp(filename, "-")) {
 			out->fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 			if (out->fd < 0) {
 				error_errno("open");
 				free(out);
 				return NULL;
 			}
 		} else {
 			out->fd = STDOUT_FILENO;
 		}
 		out->ops = &file_ops;
 	}
 	out->sparse = sparse;
 	out->cur_out_ptr = 0ll;
 	out->chunk_cnt = 0;

 	/* Initialize the crc32 value */
 	out->crc32 = 0;
 	out->use_crc = crc;

 	if (wipe)
 		wipe_block_device(out->fd, info.len);

 	if (out->sparse) {
 		sparse_header.blk_sz = info.block_size,
 		sparse_header.total_blks = info.len / info.block_size,
 		sparse_header.total_chunks = chunks;
 		if (out->use_crc)
 			sparse_header.total_chunks++;

 		ret = out->ops->write(out, (u8 *)&sparse_header, sizeof(sparse_header));
 		if (ret < 0)
 			return NULL;
 	}

 	return out;
 }

 void pad_output_file(struct output_file *out, u64 len)
 {
 	int ret;

 	if (len > (u64) info.len) {
 		error("attempted to pad file %llu bytes past end of filesystem",
 				len - info.len);
 		return;
 	}
 	if (out->sparse) {
 		/* We need to emit a DONT_CARE chunk to pad out the file if the
 		 * cur_out_ptr is not already at the end of the filesystem.
 		 */
 		if (len < out->cur_out_ptr) {
 			error("attempted to pad file %llu bytes less than the current output pointer",
 					out->cur_out_ptr - len);
 			return;
 		}
 		if (len > out->cur_out_ptr) {
 			emit_skip_chunk(out, len - out->cur_out_ptr);
 		}
 	} else {
 		//KEN TODO: Fixme.  If the filesystem image needs no padding,
 		//          this will overwrite the last byte in the file with 0
 		//          The answer is to do accounting like the sparse image
 		//          code does and know if there is already data there.
 		ret = out->ops->seek(out, len - 1);
 		if (ret < 0)
 			return;

 		ret = out->ops->write(out, (u8*)"", 1);
 		if (ret < 0)
 			return;
 	}
 }

 /* Write a contiguous region of data blocks from a memory buffer */
 void write_data_block(struct output_file *out, u64 off, u8 *data, int len)
 {
 	int ret;

 	if (off + len > (u64) info.len) {
 		error("attempted to write block %llu past end of filesystem",
 				off + len - info.len);
 		return;
 	}

 	if (out->sparse) {
 		write_chunk_raw(out, off, data, len);
 	} else {
 		ret = out->ops->seek(out, off);
 		if (ret < 0)
 			return;

 		ret = out->ops->write(out, data, len);
 		if (ret < 0)
 			return;
 	}
 }

 /* Write a contiguous region of data blocks with a fill value */
 void write_fill_block(struct output_file *out, u64 off, u32 fill_val, int len)
 {
 	int ret;
 	unsigned int i;
 	int write_len;
 	u32 fill_buf[4096/sizeof(u32)]; /* Maximum size of a block */

 	if (off + len > (u64) info.len) {
 		error("attempted to write block %llu past end of filesystem",
 				off + len - info.len);
 		return;
 	}

 	if (out->sparse) {
 		write_chunk_fill(out, off, fill_val, len);
 	} else {
 		/* Initialize fill_buf with the fill_val */
 		for (i = 0; i < sizeof(fill_buf)/sizeof(u32); i++) {
 			fill_buf[i] = fill_val;
 		}

 		ret = out->ops->seek(out, off);
 		if (ret < 0)
 			return;

 		while (len) {
 			write_len = (len > (int)sizeof(fill_buf) ? (int)sizeof(fill_buf) : len);
 			ret = out->ops->write(out, (u8 *)fill_buf, write_len);
 			if (ret < 0) {
 				return;
 			} else {
 				len -= write_len;
 			}
 		}
 	}
 }

 /* Write a contiguous region of data blocks from a file */
 void write_data_file(struct output_file *out, u64 off, const char *file,
 		     off64_t offset, int len)
 {
 	int ret;
 	off64_t aligned_offset;
 	int aligned_diff;

 	if (off + len >= (u64) info.len) {
 		error("attempted to write block %llu past end of filesystem",
 				off + len - info.len);
 		return;
 	}

 	int file_fd = open(file, O_RDONLY);
 	if (file_fd < 0) {
 		error_errno("open");
 		return;
 	}

 	aligned_offset = offset & ~(4096 - 1);
 	aligned_diff = offset - aligned_offset;

 	u8 *data = mmap64(NULL, len + aligned_diff, PROT_READ, MAP_SHARED, file_fd,
 			aligned_offset);
 	if (data == MAP_FAILED) {
 		error_errno("mmap64");
 		close(file_fd);
 		return;
 	}

 	if (out->sparse) {
 		write_chunk_raw(out, off, data + aligned_diff, len);
 	} else {
 		ret = out->ops->seek(out, off);
 		if (ret < 0)
 			goto err;

 		ret = out->ops->write(out, data + aligned_diff, len);
 		if (ret < 0)
 			goto err;
 	}

 err:
 	munmap(data, len);
 	close(file_fd);
 }
	/*
	* 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.h"
	#include "output_file.h"
	#include "sparse_format.h"
	#include "sparse_crc32.h"
	#include "wipe.h"

	#include <sys/types.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <sys/mman.h>
	#include <unistd.h>
	#include <fcntl.h>

	#include <zlib.h>

	#if defined(__APPLE__) && defined(__MACH__)
	#define lseek64 lseek
	#define off64_t off_t
	#endif

	#define SPARSE_HEADER_MAJOR_VER 1
	#define SPARSE_HEADER_MINOR_VER 0
	#define SPARSE_HEADER_LEN (sizeof(sparse_header_t))
	#define CHUNK_HEADER_LEN (sizeof(chunk_header_t))

	struct output_file_ops {
	int (seek)(struct output_file , off64_t);
	int (write)(struct output_file , u8 *, int);
	void (close)(struct output_file );
	};

	struct output_file {
	int fd;
	gzFile gz_fd;
	int sparse;
	u64 cur_out_ptr;
	u32 chunk_cnt;
	u32 crc32;
	struct output_file_ops *ops;
	int use_crc;
	};

	static int file_seek(struct output_file *out, off64_t off)
	{
	off64_t ret;

	ret = lseek64(out->fd, off, SEEK_SET);
	if (ret < 0) {
	error_errno("lseek64");
	return -1;
	}
	return 0;
	}

	static int file_write(struct output_file out, u8 data, int len)
	{
	int ret;
	ret = write(out->fd, data, len);
	if (ret < 0) {
	error_errno("write");
	return -1;
	} else if (ret < len) {
	error("incomplete write");
	return -1;
	}

	return 0;
	}

	static void file_close(struct output_file *out)
	{
	close(out->fd);
	}


	static struct output_file_ops file_ops = {
	.seek = file_seek,
	.write = file_write,
	.close = file_close,
	};

	static int gz_file_seek(struct output_file *out, off64_t off)
	{
	off64_t ret;

	ret = gzseek(out->gz_fd, off, SEEK_SET);
	if (ret < 0) {
	error_errno("gzseek");
	return -1;
	}
	return 0;
	}

	static int gz_file_write(struct output_file out, u8 data, int len)
	{
	int ret;
	ret = gzwrite(out->gz_fd, data, len);
	if (ret < 0) {
	error_errno("gzwrite");
	return -1;
	} else if (ret < len) {
	error("incomplete gzwrite");
	return -1;
	}

	return 0;
	}

	static void gz_file_close(struct output_file *out)
	{
	gzclose(out->gz_fd);
	}

	static struct output_file_ops gz_file_ops = {
	.seek = gz_file_seek,
	.write = gz_file_write,
	.close = gz_file_close,
	};

	static sparse_header_t sparse_header = {
	.magic = SPARSE_HEADER_MAGIC,
	.major_version = SPARSE_HEADER_MAJOR_VER,
	.minor_version = SPARSE_HEADER_MINOR_VER,
	.file_hdr_sz = SPARSE_HEADER_LEN,
	.chunk_hdr_sz = CHUNK_HEADER_LEN,
	.blk_sz = 0,
	.total_blks = 0,
	.total_chunks = 0,
	.image_checksum = 0
	};

	static u8 *zero_buf;

	static int emit_skip_chunk(struct output_file *out, u64 skip_len)
	{
	chunk_header_t chunk_header;
	int ret, chunk;

	//DBG printf("skip chunk: 0x%llx bytes\n", skip_len);

	if (skip_len % info.block_size) {
	error("don't care size %llu is not a multiple of the block size %u",
	skip_len, info.block_size);
	return -1;
	}

	/* We are skipping data, so emit a don't care chunk. */
	chunk_header.chunk_type = CHUNK_TYPE_DONT_CARE;
	chunk_header.reserved1 = 0;
	chunk_header.chunk_sz = skip_len / info.block_size;
	chunk_header.total_sz = CHUNK_HEADER_LEN;
	ret = out->ops->write(out, (u8 *)&chunk_header, sizeof(chunk_header));
	if (ret < 0)
	return -1;

	out->cur_out_ptr += skip_len;
	out->chunk_cnt++;

	return 0;
	}

	static int write_chunk_fill(struct output_file *out, u64 off, u32 fill_val, int len)
	{
	chunk_header_t chunk_header;
	int rnd_up_len, zero_len, count;
	int ret;
	unsigned int i;
	u32 fill_buf[4096/sizeof(u32)]; /* Maximum size of a block */

	/* We can assume that all the chunks to be written are in
	* ascending order, block-size aligned, and non-overlapping.
	* So, if the offset is less than the current output pointer,
	* throw an error, and if there is a gap, emit a "don't care"
	* chunk. The first write (of the super block) may not be
	* blocksize aligned, so we need to deal with that too.
	*/
	//DBG printf("write chunk: offset 0x%llx, length 0x%x bytes\n", off, len);

	if (off < out->cur_out_ptr) {
	error("offset %llu is less than the current output offset %llu",
	off, out->cur_out_ptr);
	return -1;
	}

	if (off > out->cur_out_ptr) {
	emit_skip_chunk(out, off - out->cur_out_ptr);
	}

	if (off % info.block_size) {
	error("write chunk offset %llu is not a multiple of the block size %u",
	off, info.block_size);
	return -1;
	}

	if (off != out->cur_out_ptr) {
	error("internal error, offset accounting screwy in write_chunk_raw()");
	return -1;
	}

	/* Round up the file length to a multiple of the block size */
	rnd_up_len = (len + (info.block_size - 1)) & (~(info.block_size -1));

	/* Finally we can safely emit a chunk of data */
	chunk_header.chunk_type = CHUNK_TYPE_FILL;
	chunk_header.reserved1 = 0;
	chunk_header.chunk_sz = rnd_up_len / info.block_size;
	chunk_header.total_sz = CHUNK_HEADER_LEN + sizeof(fill_val);
	ret = out->ops->write(out, (u8 *)&chunk_header, sizeof(chunk_header));

	if (ret < 0)
	return -1;
	ret = out->ops->write(out, (u8 *)&fill_val, sizeof(fill_val));
	if (ret < 0)
	return -1;

	if (out->use_crc) {
	/* Initialize fill_buf with the fill_val */
	for (i = 0; i < (info.block_size / sizeof(u32)); i++) {
	fill_buf[i] = fill_val;
	}

	count = chunk_header.chunk_sz;
	while (count) {
	out->crc32 = sparse_crc32(out->crc32, fill_buf, info.block_size);
	count--;
	}
	}

	out->cur_out_ptr += rnd_up_len;
	out->chunk_cnt++;

	return 0;
	}

	static int write_chunk_raw(struct output_file out, u64 off, u8 data, int len)
	{
	chunk_header_t chunk_header;
	int rnd_up_len, zero_len;
	int ret;

	/* We can assume that all the chunks to be written are in
	* ascending order, block-size aligned, and non-overlapping.
	* So, if the offset is less than the current output pointer,
	* throw an error, and if there is a gap, emit a "don't care"
	* chunk. The first write (of the super block) may not be
	* blocksize aligned, so we need to deal with that too.
	*/
	//DBG printf("write chunk: offset 0x%llx, length 0x%x bytes\n", off, len);

	if (off < out->cur_out_ptr) {
	error("offset %llu is less than the current output offset %llu",
	off, out->cur_out_ptr);
	return -1;
	}

	if (off > out->cur_out_ptr) {
	emit_skip_chunk(out, off - out->cur_out_ptr);
	}

	if (off % info.block_size) {
	error("write chunk offset %llu is not a multiple of the block size %u",
	off, info.block_size);
	return -1;
	}

	if (off != out->cur_out_ptr) {
	error("internal error, offset accounting screwy in write_chunk_raw()");
	return -1;
	}

	/* Round up the file length to a multiple of the block size */
	rnd_up_len = (len + (info.block_size - 1)) & (~(info.block_size -1));
	zero_len = rnd_up_len - len;

	/* Finally we can safely emit a chunk of data */
	chunk_header.chunk_type = CHUNK_TYPE_RAW;
	chunk_header.reserved1 = 0;
	chunk_header.chunk_sz = rnd_up_len / info.block_size;
	chunk_header.total_sz = CHUNK_HEADER_LEN + rnd_up_len;
	ret = out->ops->write(out, (u8 *)&chunk_header, sizeof(chunk_header));

	if (ret < 0)
	return -1;
	ret = out->ops->write(out, data, len);
	if (ret < 0)
	return -1;
	if (zero_len) {
	ret = out->ops->write(out, zero_buf, zero_len);
	if (ret < 0)
	return -1;
	}

	if (out->use_crc) {
	out->crc32 = sparse_crc32(out->crc32, data, len);
	if (zero_len)
	out->crc32 = sparse_crc32(out->crc32, zero_buf, zero_len);
	}

	out->cur_out_ptr += rnd_up_len;
	out->chunk_cnt++;

	return 0;
	}

	void close_output_file(struct output_file *out)
	{
	int ret;
	chunk_header_t chunk_header;

	if (out->sparse) {
	if (out->use_crc) {
	chunk_header.chunk_type = CHUNK_TYPE_CRC32;
	chunk_header.reserved1 = 0;
	chunk_header.chunk_sz = 0;
	chunk_header.total_sz = CHUNK_HEADER_LEN + 4;

	out->ops->write(out, (u8 *)&chunk_header, sizeof(chunk_header));
	out->ops->write(out, (u8 *)&out->crc32, 4);

	out->chunk_cnt++;
	}

	if (out->chunk_cnt != sparse_header.total_chunks)
	error("sparse chunk count did not match: %d %d", out->chunk_cnt,
	sparse_header.total_chunks);
	}
	out->ops->close(out);
	}

	struct output_file open_output_file(const char filename, int gz, int sparse,
	int chunks, int crc, int wipe)
	{
	int ret;
	struct output_file *out = malloc(sizeof(struct output_file));
	if (!out) {
	error_errno("malloc struct out");
	return NULL;
	}
	zero_buf = malloc(info.block_size);
	if (!zero_buf) {
	error_errno("malloc zero_buf");
	free(out);
	return NULL;
	}
	memset(zero_buf, '\0', info.block_size);

	if (gz) {
	out->ops = &gz_file_ops;
	out->gz_fd = gzopen(filename, "wb9");
	if (!out->gz_fd) {
	error_errno("gzopen");
	free(out);
	return NULL;
	}
	} else {
	if (strcmp(filename, "-")) {
	out->fd = open(filename, O_WRONLY \| O_CREAT \| O_TRUNC, 0644);
	if (out->fd < 0) {
	error_errno("open");
	free(out);
	return NULL;
	}
	} else {
	out->fd = STDOUT_FILENO;
	}
	out->ops = &file_ops;
	}
	out->sparse = sparse;
	out->cur_out_ptr = 0ll;
	out->chunk_cnt = 0;

	/* Initialize the crc32 value */
	out->crc32 = 0;
	out->use_crc = crc;

	if (wipe)
	wipe_block_device(out->fd, info.len);

	if (out->sparse) {
	sparse_header.blk_sz = info.block_size,
	sparse_header.total_blks = info.len / info.block_size,
	sparse_header.total_chunks = chunks;
	if (out->use_crc)
	sparse_header.total_chunks++;

	ret = out->ops->write(out, (u8 *)&sparse_header, sizeof(sparse_header));
	if (ret < 0)
	return NULL;
	}

	return out;
	}

	void pad_output_file(struct output_file *out, u64 len)
	{
	int ret;

	if (len > (u64) info.len) {
	error("attempted to pad file %llu bytes past end of filesystem",
	len - info.len);
	return;
	}
	if (out->sparse) {
	/* We need to emit a DONT_CARE chunk to pad out the file if the
	* cur_out_ptr is not already at the end of the filesystem.
	*/
	if (len < out->cur_out_ptr) {
	error("attempted to pad file %llu bytes less than the current output pointer",
	out->cur_out_ptr - len);
	return;
	}
	if (len > out->cur_out_ptr) {
	emit_skip_chunk(out, len - out->cur_out_ptr);
	}
	} else {
	//KEN TODO: Fixme. If the filesystem image needs no padding,
	// this will overwrite the last byte in the file with 0
	// The answer is to do accounting like the sparse image
	// code does and know if there is already data there.
	ret = out->ops->seek(out, len - 1);
	if (ret < 0)
	return;

	ret = out->ops->write(out, (u8*)"", 1);
	if (ret < 0)
	return;
	}
	}

	/* Write a contiguous region of data blocks from a memory buffer */
	void write_data_block(struct output_file out, u64 off, u8 data, int len)
	{
	int ret;

	if (off + len > (u64) info.len) {
	error("attempted to write block %llu past end of filesystem",
	off + len - info.len);
	return;
	}

	if (out->sparse) {
	write_chunk_raw(out, off, data, len);
	} else {
	ret = out->ops->seek(out, off);
	if (ret < 0)
	return;

	ret = out->ops->write(out, data, len);
	if (ret < 0)
	return;
	}
	}

	/* Write a contiguous region of data blocks with a fill value */
	void write_fill_block(struct output_file *out, u64 off, u32 fill_val, int len)
	{
	int ret;
	unsigned int i;
	int write_len;
	u32 fill_buf[4096/sizeof(u32)]; /* Maximum size of a block */

	if (off + len > (u64) info.len) {
	error("attempted to write block %llu past end of filesystem",
	off + len - info.len);
	return;
	}

	if (out->sparse) {
	write_chunk_fill(out, off, fill_val, len);
	} else {
	/* Initialize fill_buf with the fill_val */
	for (i = 0; i < sizeof(fill_buf)/sizeof(u32); i++) {
	fill_buf[i] = fill_val;
	}

	ret = out->ops->seek(out, off);
	if (ret < 0)
	return;

	while (len) {
	write_len = (len > (int)sizeof(fill_buf) ? (int)sizeof(fill_buf) : len);
	ret = out->ops->write(out, (u8 *)fill_buf, write_len);
	if (ret < 0) {
	return;
	} else {
	len -= write_len;
	}
	}
	}
	}

	/* Write a contiguous region of data blocks from a file */
	void write_data_file(struct output_file out, u64 off, const char file,
	off64_t offset, int len)
	{
	int ret;
	off64_t aligned_offset;
	int aligned_diff;

	if (off + len >= (u64) info.len) {
	error("attempted to write block %llu past end of filesystem",
	off + len - info.len);
	return;
	}

	int file_fd = open(file, O_RDONLY);
	if (file_fd < 0) {
	error_errno("open");
	return;
	}

	aligned_offset = offset & ~(4096 - 1);
	aligned_diff = offset - aligned_offset;

	u8 *data = mmap64(NULL, len + aligned_diff, PROT_READ, MAP_SHARED, file_fd,
	aligned_offset);
	if (data == MAP_FAILED) {
	error_errno("mmap64");
	close(file_fd);
	return;
	}

	if (out->sparse) {
	write_chunk_raw(out, off, data + aligned_diff, len);
	} else {
	ret = out->ops->seek(out, off);
	if (ret < 0)
	goto err;

	ret = out->ops->write(out, data + aligned_diff, len);
	if (ret < 0)
	goto err;
	}

	err:
	munmap(data, len);
	close(file_fd);
	}