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qemu/block/raw-format.c

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/* BlockDriver implementation for "raw" format driver
*
* Copyright (C) 2010-2016 Red Hat, Inc.
* Copyright (C) 2010, Blue Swirl <blauwirbel@gmail.com>
* Copyright (C) 2009, Anthony Liguori <aliguori@us.ibm.com>
*
* Author:
* Laszlo Ersek <lersek@redhat.com>
*
* 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 "block/block_int.h"
#include "qapi/error.h"
#include "qemu/module.h"
#include "qemu/option.h"
typedef struct BDRVRawState {
uint64_t offset;
uint64_t size;
bool has_size;
} BDRVRawState;
static const char *const mutable_opts[] = { "offset", "size", NULL };
static QemuOptsList raw_runtime_opts = {
.name = "raw",
.head = QTAILQ_HEAD_INITIALIZER(raw_runtime_opts.head),
.desc = {
{
.name = "offset",
.type = QEMU_OPT_SIZE,
.help = "offset in the disk where the image starts",
},
{
.name = "size",
.type = QEMU_OPT_SIZE,
.help = "virtual disk size",
},
{ /* end of list */ }
},
};
static QemuOptsList raw_create_opts = {
.name = "raw-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size"
},
{ /* end of list */ }
}
};
static int raw_read_options(QDict *options, BlockDriverState *bs,
BDRVRawState *s, Error **errp)
{
Error *local_err = NULL;
QemuOpts *opts = NULL;
int64_t real_size = 0;
int ret;
real_size = bdrv_getlength(bs->file->bs);
if (real_size < 0) {
error_setg_errno(errp, -real_size, "Could not get image size");
return real_size;
}
opts = qemu_opts_create(&raw_runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto end;
}
s->offset = qemu_opt_get_size(opts, "offset", 0);
if (s->offset > real_size) {
error_setg(errp, "Offset (%" PRIu64 ") cannot be greater than "
"size of the containing file (%" PRId64 ")",
s->offset, real_size);
ret = -EINVAL;
goto end;
}
if (qemu_opt_find(opts, "size") != NULL) {
s->size = qemu_opt_get_size(opts, "size", 0);
s->has_size = true;
} else {
s->has_size = false;
s->size = real_size - s->offset;
}
/* Check size and offset */
if ((real_size - s->offset) < s->size) {
error_setg(errp, "The sum of offset (%" PRIu64 ") and size "
"(%" PRIu64 ") has to be smaller or equal to the "
" actual size of the containing file (%" PRId64 ")",
s->offset, s->size, real_size);
ret = -EINVAL;
goto end;
}
/* Make sure size is multiple of BDRV_SECTOR_SIZE to prevent rounding
* up and leaking out of the specified area. */
if (s->has_size && !QEMU_IS_ALIGNED(s->size, BDRV_SECTOR_SIZE)) {
error_setg(errp, "Specified size is not multiple of %llu",
BDRV_SECTOR_SIZE);
ret = -EINVAL;
goto end;
}
ret = 0;
end:
qemu_opts_del(opts);
return ret;
}
static int raw_reopen_prepare(BDRVReopenState *reopen_state,
BlockReopenQueue *queue, Error **errp)
{
assert(reopen_state != NULL);
assert(reopen_state->bs != NULL);
reopen_state->opaque = g_new0(BDRVRawState, 1);
return raw_read_options(
reopen_state->options,
reopen_state->bs,
reopen_state->opaque,
errp);
}
static void raw_reopen_commit(BDRVReopenState *state)
{
BDRVRawState *new_s = state->opaque;
BDRVRawState *s = state->bs->opaque;
memcpy(s, new_s, sizeof(BDRVRawState));
g_free(state->opaque);
state->opaque = NULL;
}
static void raw_reopen_abort(BDRVReopenState *state)
{
g_free(state->opaque);
state->opaque = NULL;
}
/* Check and adjust the offset, against 'offset' and 'size' options. */
static inline int raw_adjust_offset(BlockDriverState *bs, uint64_t *offset,
uint64_t bytes, bool is_write)
{
BDRVRawState *s = bs->opaque;
if (s->has_size && (*offset > s->size || bytes > (s->size - *offset))) {
/* There's not enough space for the write, or the read request is
* out-of-range. Don't read/write anything to prevent leaking out of
* the size specified in options. */
return is_write ? -ENOSPC : -EINVAL;
}
if (*offset > INT64_MAX - s->offset) {
return -EINVAL;
}
*offset += s->offset;
return 0;
}
static int coroutine_fn raw_co_preadv(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
int ret;
ret = raw_adjust_offset(bs, &offset, bytes, false);
if (ret) {
return ret;
}
BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
}
static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
void *buf = NULL;
BlockDriver *drv;
QEMUIOVector local_qiov;
int ret;
if (bs->probed && offset < BLOCK_PROBE_BUF_SIZE && bytes) {
/* Handling partial writes would be a pain - so we just
* require that guests have 512-byte request alignment if
* probing occurred */
QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);
assert(offset == 0 && bytes >= BLOCK_PROBE_BUF_SIZE);
buf = qemu_try_blockalign(bs->file->bs, 512);
if (!buf) {
ret = -ENOMEM;
goto fail;
}
ret = qemu_iovec_to_buf(qiov, 0, buf, 512);
if (ret != 512) {
ret = -EINVAL;
goto fail;
}
drv = bdrv_probe_all(buf, 512, NULL);
if (drv != bs->drv) {
ret = -EPERM;
goto fail;
}
/* Use the checked buffer, a malicious guest might be overwriting its
* original buffer in the background. */
qemu_iovec_init(&local_qiov, qiov->niov + 1);
qemu_iovec_add(&local_qiov, buf, 512);
qemu_iovec_concat(&local_qiov, qiov, 512, qiov->size - 512);
qiov = &local_qiov;
}
ret = raw_adjust_offset(bs, &offset, bytes, true);
if (ret) {
goto fail;
}
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
ret = bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
fail:
if (qiov == &local_qiov) {
qemu_iovec_destroy(&local_qiov);
}
qemu_vfree(buf);
return ret;
}
static int coroutine_fn raw_co_block_status(BlockDriverState *bs,
bool want_zero, int64_t offset,
int64_t bytes, int64_t *pnum,
int64_t *map,
BlockDriverState **file)
{
BDRVRawState *s = bs->opaque;
*pnum = bytes;
*file = bs->file->bs;
*map = offset + s->offset;
return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID;
}
static int coroutine_fn raw_co_pwrite_zeroes(BlockDriverState *bs,
int64_t offset, int bytes,
BdrvRequestFlags flags)
{
int ret;
ret = raw_adjust_offset(bs, (uint64_t *)&offset, bytes, true);
if (ret) {
return ret;
}
return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
}
static int coroutine_fn raw_co_pdiscard(BlockDriverState *bs,
int64_t offset, int bytes)
{
int ret;
ret = raw_adjust_offset(bs, (uint64_t *)&offset, bytes, true);
if (ret) {
return ret;
}
return bdrv_co_pdiscard(bs->file, offset, bytes);
}
static int64_t raw_getlength(BlockDriverState *bs)
{
int64_t len;
BDRVRawState *s = bs->opaque;
/* Update size. It should not change unless the file was externally
* modified. */
len = bdrv_getlength(bs->file->bs);
if (len < 0) {
return len;
}
if (len < s->offset) {
s->size = 0;
} else {
if (s->has_size) {
/* Try to honour the size */
s->size = MIN(s->size, len - s->offset);
} else {
s->size = len - s->offset;
}
}
return s->size;
}
static BlockMeasureInfo *raw_measure(QemuOpts *opts, BlockDriverState *in_bs,
Error **errp)
{
BlockMeasureInfo *info;
int64_t required;
if (in_bs) {
required = bdrv_getlength(in_bs);
if (required < 0) {
error_setg_errno(errp, -required, "Unable to get image size");
return NULL;
}
} else {
required = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
BDRV_SECTOR_SIZE);
}
info = g_new(BlockMeasureInfo, 1);
info->required = required;
/* Unallocated sectors count towards the file size in raw images */
info->fully_allocated = info->required;
return info;
}
static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
return bdrv_get_info(bs->file->bs, bdi);
}
static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
{
if (bs->probed) {
/* To make it easier to protect the first sector, any probed
* image is restricted to read-modify-write on sub-sector
* operations. */
bs->bl.request_alignment = BDRV_SECTOR_SIZE;
}
}
static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
PreallocMode prealloc, Error **errp)
{
BDRVRawState *s = bs->opaque;
if (s->has_size) {
error_setg(errp, "Cannot resize fixed-size raw disks");
return -ENOTSUP;
}
if (INT64_MAX - offset < s->offset) {
error_setg(errp, "Disk size too large for the chosen offset");
return -EINVAL;
}
s->size = offset;
offset += s->offset;
return bdrv_co_truncate(bs->file, offset, prealloc, errp);
}
static void raw_eject(BlockDriverState *bs, bool eject_flag)
{
bdrv_eject(bs->file->bs, eject_flag);
}
static void raw_lock_medium(BlockDriverState *bs, bool locked)
{
bdrv_lock_medium(bs->file->bs, locked);
}
static int raw_co_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
{
BDRVRawState *s = bs->opaque;
if (s->offset || s->has_size) {
return -ENOTSUP;
}
return bdrv_co_ioctl(bs->file->bs, req, buf);
}
static int raw_has_zero_init(BlockDriverState *bs)
{
return bdrv_has_zero_init(bs->file->bs);
}
static int raw_has_zero_init_truncate(BlockDriverState *bs)
{
return bdrv_has_zero_init_truncate(bs->file->bs);
}
static int coroutine_fn raw_co_create_opts(const char *filename, QemuOpts *opts,
Error **errp)
{
return bdrv_create_file(filename, opts, errp);
}
static int raw_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVRawState *s = bs->opaque;
int ret;
bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
false, errp);
if (!bs->file) {
return -EINVAL;
}
bs->sg = bs->file->bs->sg;
bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
(BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
bs->file->bs->supported_zero_flags);
if (bs->probed && !bdrv_is_read_only(bs)) {
bdrv_refresh_filename(bs->file->bs);
fprintf(stderr,
"WARNING: Image format was not specified for '%s' and probing "
"guessed raw.\n"
" Automatically detecting the format is dangerous for "
"raw images, write operations on block 0 will be restricted.\n"
" Specify the 'raw' format explicitly to remove the "
"restrictions.\n",
bs->file->bs->filename);
}
ret = raw_read_options(options, bs, s, errp);
if (ret < 0) {
return ret;
}
if (bs->sg && (s->offset || s->has_size)) {
error_setg(errp, "Cannot use offset/size with SCSI generic devices");
return -EINVAL;
}
return 0;
}
static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
{
/* smallest possible positive score so that raw is used if and only if no
* other block driver works
*/
return 1;
}
static int raw_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
{
BDRVRawState *s = bs->opaque;
int ret;
ret = bdrv_probe_blocksizes(bs->file->bs, bsz);
if (ret < 0) {
return ret;
}
if (!QEMU_IS_ALIGNED(s->offset, MAX(bsz->log, bsz->phys))) {
return -ENOTSUP;
}
return 0;
}
static int raw_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
{
BDRVRawState *s = bs->opaque;
if (s->offset || s->has_size) {
return -ENOTSUP;
}
return bdrv_probe_geometry(bs->file->bs, geo);
}
static int coroutine_fn raw_co_copy_range_from(BlockDriverState *bs,
BdrvChild *src,
uint64_t src_offset,
BdrvChild *dst,
uint64_t dst_offset,
uint64_t bytes,
BdrvRequestFlags read_flags,
BdrvRequestFlags write_flags)
{
int ret;
ret = raw_adjust_offset(bs, &src_offset, bytes, false);
if (ret) {
return ret;
}
return bdrv_co_copy_range_from(bs->file, src_offset, dst, dst_offset,
bytes, read_flags, write_flags);
}
static int coroutine_fn raw_co_copy_range_to(BlockDriverState *bs,
BdrvChild *src,
uint64_t src_offset,
BdrvChild *dst,
uint64_t dst_offset,
uint64_t bytes,
BdrvRequestFlags read_flags,
BdrvRequestFlags write_flags)
{
int ret;
ret = raw_adjust_offset(bs, &dst_offset, bytes, true);
if (ret) {
return ret;
}
return bdrv_co_copy_range_to(src, src_offset, bs->file, dst_offset, bytes,
read_flags, write_flags);
}
static const char *const raw_strong_runtime_opts[] = {
"offset",
"size",
NULL
};
BlockDriver bdrv_raw = {
.format_name = "raw",
.instance_size = sizeof(BDRVRawState),
.bdrv_probe = &raw_probe,
.bdrv_reopen_prepare = &raw_reopen_prepare,
.bdrv_reopen_commit = &raw_reopen_commit,
.bdrv_reopen_abort = &raw_reopen_abort,
.bdrv_open = &raw_open,
.bdrv_child_perm = bdrv_filter_default_perms,
.bdrv_co_create_opts = &raw_co_create_opts,
.bdrv_co_preadv = &raw_co_preadv,
.bdrv_co_pwritev = &raw_co_pwritev,
.bdrv_co_pwrite_zeroes = &raw_co_pwrite_zeroes,
.bdrv_co_pdiscard = &raw_co_pdiscard,
.bdrv_co_block_status = &raw_co_block_status,
.bdrv_co_copy_range_from = &raw_co_copy_range_from,
.bdrv_co_copy_range_to = &raw_co_copy_range_to,
.bdrv_co_truncate = &raw_co_truncate,
.bdrv_getlength = &raw_getlength,
.has_variable_length = true,
.bdrv_measure = &raw_measure,
.bdrv_get_info = &raw_get_info,
.bdrv_refresh_limits = &raw_refresh_limits,
.bdrv_probe_blocksizes = &raw_probe_blocksizes,
.bdrv_probe_geometry = &raw_probe_geometry,
.bdrv_eject = &raw_eject,
.bdrv_lock_medium = &raw_lock_medium,
.bdrv_co_ioctl = &raw_co_ioctl,
.create_opts = &raw_create_opts,
.bdrv_has_zero_init = &raw_has_zero_init,
.bdrv_has_zero_init_truncate = &raw_has_zero_init_truncate,
.strong_runtime_opts = raw_strong_runtime_opts,
.mutable_opts = mutable_opts,
};
static void bdrv_raw_init(void)
{
bdrv_register(&bdrv_raw);
}
block_init(bdrv_raw_init);
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