qemu/block/cloop.c
Max Reitz 69dca43d6b block: Use bdrv_default_perms()
bdrv_default_perms() can decide which permission profile to use based on
the BdrvChildRole, so block drivers do not need to select it explicitly.

The blkverify driver now no longer shares the WRITE permission for the
image to verify.  We thus have to adjust two places in
test-block-iothread not to take it.  (Note that in theory, blkverify
should behave like quorum in this regard and share neither WRITE nor
RESIZE for both of its children.  In practice, it does not really
matter, because blkverify is used only for debugging, so we might as
well keep its permissions rather liberal.)

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200513110544.176672-30-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18 19:05:25 +02:00

309 lines
9.3 KiB
C

/*
* 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/osdep.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "block/block_int.h"
#include "qemu/module.h"
#include "qemu/bswap.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;
ret = bdrv_apply_auto_read_only(bs, NULL, errp);
if (ret < 0) {
return ret;
}
bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
BDRV_CHILD_IMAGE, false, errp);
if (!bs->file) {
return -EINVAL;
}
/* 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 void cloop_refresh_limits(BlockDriverState *bs, Error **errp)
{
bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */
}
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 coroutine_fn
cloop_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags)
{
BDRVCloopState *s = bs->opaque;
uint64_t sector_num = offset >> BDRV_SECTOR_BITS;
int nb_sectors = bytes >> BDRV_SECTOR_BITS;
int ret, i;
assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));
qemu_co_mutex_lock(&s->lock);
for (i = 0; i < nb_sectors; i++) {
void *data;
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) {
ret = -EIO;
goto fail;
}
data = s->uncompressed_block + sector_offset_in_block * 512;
qemu_iovec_from_buf(qiov, i * 512, data, 512);
}
ret = 0;
fail:
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_child_perm = bdrv_default_perms,
.bdrv_refresh_limits = cloop_refresh_limits,
.bdrv_co_preadv = cloop_co_preadv,
.bdrv_close = cloop_close,
.is_format = true,
};
static void bdrv_cloop_init(void)
{
bdrv_register(&bdrv_cloop);
}
block_init(bdrv_cloop_init);