/*
* QEMU Block driver for CLOOP images
*
* Copyright (c) 2004 Johannes E. Schindelin
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu-common.h"
#include "block/block_int.h"
#include "qemu/module.h"
#include <zlib.h>
/* Maximum compressed block size */
#define MAX_BLOCK_SIZE (64 * 1024 * 1024)
typedef struct BDRVCloopState {
CoMutex lock;
uint32_t block_size;
uint32_t n_blocks;
uint64_t *offsets;
uint32_t sectors_per_block;
uint32_t current_block;
uint8_t *compressed_block;
uint8_t *uncompressed_block;
z_stream zstream;
} BDRVCloopState;
static int cloop_probe(const uint8_t *buf, int buf_size, const char *filename)
{
const char *magic_version_2_0 = "#!/bin/sh\n"
"#V2.0 Format\n"
"modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n";
int length = strlen(magic_version_2_0);
if (length > buf_size) {
length = buf_size;
}
if (!memcmp(magic_version_2_0, buf, length)) {
return 2;
}
return 0;
}
static int cloop_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVCloopState *s = bs->opaque;
uint32_t offsets_size, max_compressed_block_size = 1, i;
int ret;
bs->read_only = 1;
/* read header */
ret = bdrv_pread(bs->file, 128, &s->block_size, 4);
if (ret < 0) {
return ret;
}
s->block_size = be32_to_cpu(s->block_size);
if (s->block_size % 512) {
error_setg(errp, "block_size %" PRIu32 " must be a multiple of 512",
s->block_size);
return -EINVAL;
}
if (s->block_size == 0) {
error_setg(errp, "block_size cannot be zero");
return -EINVAL;
}
/* cloop's create_compressed_fs.c warns about block sizes beyond 256 KB but
* we can accept more. Prevent ridiculous values like 4 GB - 1 since we
* need a buffer this big.
*/
if (s->block_size > MAX_BLOCK_SIZE) {
error_setg(errp, "block_size %" PRIu32 " must be %u MB or less",
s->block_size,
MAX_BLOCK_SIZE / (1024 * 1024));
return -EINVAL;
}
ret = bdrv_pread(bs->file, 128 + 4, &s->n_blocks, 4);
if (ret < 0) {
return ret;
}
s->n_blocks = be32_to_cpu(s->n_blocks);
/* read offsets */
if (s->n_blocks > (UINT32_MAX - 1) / sizeof(uint64_t)) {
/* Prevent integer overflow */
error_setg(errp, "n_blocks %" PRIu32 " must be %zu or less",
s->n_blocks,
(UINT32_MAX - 1) / sizeof(uint64_t));
return -EINVAL;
}
offsets_size = (s->n_blocks + 1) * sizeof(uint64_t);
if (offsets_size > 512 * 1024 * 1024) {
/* Prevent ridiculous offsets_size which causes memory allocation to
* fail or overflows bdrv_pread() size. In practice the 512 MB
* offsets[] limit supports 16 TB images at 256 KB block size.
*/
error_setg(errp, "image requires too many offsets, "
"try increasing block size");
return -EINVAL;
}
s->offsets = g_try_malloc(offsets_size);
if (s->offsets == NULL) {
error_setg(errp, "Could not allocate offsets table");
return -ENOMEM;
}
ret = bdrv_pread(bs->file, 128 + 4 + 4, s->offsets, offsets_size);
if (ret < 0) {
goto fail;
}
for (i = 0; i < s->n_blocks + 1; i++) {
uint64_t size;
s->offsets[i] = be64_to_cpu(s->offsets[i]);
if (i == 0) {
continue;
}
if (s->offsets[i] < s->offsets[i - 1]) {
error_setg(errp, "offsets not monotonically increasing at "
"index %" PRIu32 ", image file is corrupt", i);
ret = -EINVAL;
goto fail;
}
size = s->offsets[i] - s->offsets[i - 1];
/* Compressed blocks should be smaller than the uncompressed block size
* but maybe compression performed poorly so the compressed block is
* actually bigger. Clamp down on unrealistic values to prevent
* ridiculous s->compressed_block allocation.
*/
if (size > 2 * MAX_BLOCK_SIZE) {
error_setg(errp, "invalid compressed block size at index %" PRIu32
", image file is corrupt", i);
ret = -EINVAL;
goto fail;
}
if (size > max_compressed_block_size) {
max_compressed_block_size = size;
}
}
/* initialize zlib engine */
s->compressed_block = g_try_malloc(max_compressed_block_size + 1);
if (s->compressed_block == NULL) {
error_setg(errp, "Could not allocate compressed_block");
ret = -ENOMEM;
goto fail;
}
s->uncompressed_block = g_try_malloc(s->block_size);
if (s->uncompressed_block == NULL) {
error_setg(errp, "Could not allocate uncompressed_block");
ret = -ENOMEM;
goto fail;
}
if (inflateInit(&s->zstream) != Z_OK) {
ret = -EINVAL;
goto fail;
}
s->current_block = s->n_blocks;
s->sectors_per_block = s->block_size/512;
bs->total_sectors = s->n_blocks * s->sectors_per_block;
qemu_co_mutex_init(&s->lock);
return 0;
fail:
g_free(s->offsets);
g_free(s->compressed_block);
g_free(s->uncompressed_block);
return ret;
}
static inline int cloop_read_block(BlockDriverState *bs, int block_num)
{
BDRVCloopState *s = bs->opaque;
if (s->current_block != block_num) {
int ret;
uint32_t bytes = s->offsets[block_num + 1] - s->offsets[block_num];
ret = bdrv_pread(bs->file, s->offsets[block_num], s->compressed_block,
bytes);
if (ret != bytes) {
return -1;
}
s->zstream.next_in = s->compressed_block;
s->zstream.avail_in = bytes;
s->zstream.next_out = s->uncompressed_block;
s->zstream.avail_out = s->block_size;
ret = inflateReset(&s->zstream);
if (ret != Z_OK) {
return -1;
}
ret = inflate(&s->zstream, Z_FINISH);
if (ret != Z_STREAM_END || s->zstream.total_out != s->block_size) {
return -1;
}
s->current_block = block_num;
}
return 0;
}
static int cloop_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
BDRVCloopState *s = bs->opaque;
int i;
for (i = 0; i < nb_sectors; i++) {
uint32_t sector_offset_in_block =
((sector_num + i) % s->sectors_per_block),
block_num = (sector_num + i) / s->sectors_per_block;
if (cloop_read_block(bs, block_num) != 0) {
return -1;
}
memcpy(buf + i * 512,
s->uncompressed_block + sector_offset_in_block * 512, 512);
}
return 0;
}
static coroutine_fn int cloop_co_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
int ret;
BDRVCloopState *s = bs->opaque;
qemu_co_mutex_lock(&s->lock);
ret = cloop_read(bs, sector_num, buf, nb_sectors);
qemu_co_mutex_unlock(&s->lock);
return ret;
}
static void cloop_close(BlockDriverState *bs)
{
BDRVCloopState *s = bs->opaque;
g_free(s->offsets);
g_free(s->compressed_block);
g_free(s->uncompressed_block);
inflateEnd(&s->zstream);
}
static BlockDriver bdrv_cloop = {
.format_name = "cloop",
.instance_size = sizeof(BDRVCloopState),
.bdrv_probe = cloop_probe,
.bdrv_open = cloop_open,
.bdrv_read = cloop_co_read,
.bdrv_close = cloop_close,
};
static void bdrv_cloop_init(void)
{
bdrv_register(&bdrv_cloop);
}
block_init(bdrv_cloop_init);
