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qemu/block/qcow.c
Jeff Cody e729fa6afe block: fix off-by-one error in qcow and qcow2 
This fixes an off-by-one error introduced in 9a29e18.  Both qcow and
qcow2 need to make sure to leave room for string terminator '\0' for
the backing file, so the max length of the non-terminated string is
either 1023 or PATH_MAX - 1.

Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00

983 lines
30 KiB
C
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/*
* Block driver for the QCOW format
*
* Copyright (c) 2004-2006 Fabrice Bellard
*
* 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>
#include "qemu/aes.h"
#include "migration/migration.h"
/**************************************************************/
/* QEMU COW block driver with compression and encryption support */
#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
#define QCOW_VERSION 1
#define QCOW_CRYPT_NONE 0
#define QCOW_CRYPT_AES 1
#define QCOW_OFLAG_COMPRESSED (1LL << 63)
typedef struct QCowHeader {
uint32_t magic;
uint32_t version;
uint64_t backing_file_offset;
uint32_t backing_file_size;
uint32_t mtime;
uint64_t size; /* in bytes */
uint8_t cluster_bits;
uint8_t l2_bits;
uint16_t padding;
uint32_t crypt_method;
uint64_t l1_table_offset;
} QEMU_PACKED QCowHeader;
#define L2_CACHE_SIZE 16
typedef struct BDRVQcowState {
int cluster_bits;
int cluster_size;
int cluster_sectors;
int l2_bits;
int l2_size;
unsigned int l1_size;
uint64_t cluster_offset_mask;
uint64_t l1_table_offset;
uint64_t *l1_table;
uint64_t *l2_cache;
uint64_t l2_cache_offsets[L2_CACHE_SIZE];
uint32_t l2_cache_counts[L2_CACHE_SIZE];
uint8_t *cluster_cache;
uint8_t *cluster_data;
uint64_t cluster_cache_offset;
uint32_t crypt_method; /* current crypt method, 0 if no key yet */
uint32_t crypt_method_header;
AES_KEY aes_encrypt_key;
AES_KEY aes_decrypt_key;
CoMutex lock;
Error *migration_blocker;
} BDRVQcowState;
static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
{
const QCowHeader *cow_header = (const void *)buf;
if (buf_size >= sizeof(QCowHeader) &&
be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
be32_to_cpu(cow_header->version) == QCOW_VERSION)
return 100;
else
return 0;
}
static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVQcowState *s = bs->opaque;
unsigned int len, i, shift;
int ret;
QCowHeader header;
ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
if (ret < 0) {
goto fail;
}
be32_to_cpus(&header.magic);
be32_to_cpus(&header.version);
be64_to_cpus(&header.backing_file_offset);
be32_to_cpus(&header.backing_file_size);
be32_to_cpus(&header.mtime);
be64_to_cpus(&header.size);
be32_to_cpus(&header.crypt_method);
be64_to_cpus(&header.l1_table_offset);
if (header.magic != QCOW_MAGIC) {
error_setg(errp, "Image not in qcow format");
ret = -EINVAL;
goto fail;
}
if (header.version != QCOW_VERSION) {
char version[64];
snprintf(version, sizeof(version), "QCOW version %" PRIu32,
header.version);
error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
bdrv_get_device_name(bs), "qcow", version);
ret = -ENOTSUP;
goto fail;
}
if (header.size <= 1) {
error_setg(errp, "Image size is too small (must be at least 2 bytes)");
ret = -EINVAL;
goto fail;
}
if (header.cluster_bits < 9 || header.cluster_bits > 16) {
error_setg(errp, "Cluster size must be between 512 and 64k");
ret = -EINVAL;
goto fail;
}
/* l2_bits specifies number of entries; storing a uint64_t in each entry,
* so bytes = num_entries << 3. */
if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
error_setg(errp, "L2 table size must be between 512 and 64k");
ret = -EINVAL;
goto fail;
}
if (header.crypt_method > QCOW_CRYPT_AES) {
error_setg(errp, "invalid encryption method in qcow header");
ret = -EINVAL;
goto fail;
}
s->crypt_method_header = header.crypt_method;
if (s->crypt_method_header) {
bs->encrypted = 1;
}
s->cluster_bits = header.cluster_bits;
s->cluster_size = 1 << s->cluster_bits;
s->cluster_sectors = 1 << (s->cluster_bits - 9);
s->l2_bits = header.l2_bits;
s->l2_size = 1 << s->l2_bits;
bs->total_sectors = header.size / 512;
s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
/* read the level 1 table */
shift = s->cluster_bits + s->l2_bits;
if (header.size > UINT64_MAX - (1LL << shift)) {
error_setg(errp, "Image too large");
ret = -EINVAL;
goto fail;
} else {
uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
if (l1_size > INT_MAX / sizeof(uint64_t)) {
error_setg(errp, "Image too large");
ret = -EINVAL;
goto fail;
}
s->l1_size = l1_size;
}
s->l1_table_offset = header.l1_table_offset;
s->l1_table = g_try_new(uint64_t, s->l1_size);
if (s->l1_table == NULL) {
error_setg(errp, "Could not allocate memory for L1 table");
ret = -ENOMEM;
goto fail;
}
ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
s->l1_size * sizeof(uint64_t));
if (ret < 0) {
goto fail;
}
for(i = 0;i < s->l1_size; i++) {
be64_to_cpus(&s->l1_table[i]);
}
/* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
s->l2_cache =
qemu_try_blockalign(bs->file,
s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
if (s->l2_cache == NULL) {
error_setg(errp, "Could not allocate L2 table cache");
ret = -ENOMEM;
goto fail;
}
s->cluster_cache = g_malloc(s->cluster_size);
s->cluster_data = g_malloc(s->cluster_size);
s->cluster_cache_offset = -1;
/* read the backing file name */
if (header.backing_file_offset != 0) {
len = header.backing_file_size;
if (len > 1023 || len >= sizeof(bs->backing_file)) {
error_setg(errp, "Backing file name too long");
ret = -EINVAL;
goto fail;
}
ret = bdrv_pread(bs->file, header.backing_file_offset,
bs->backing_file, len);
if (ret < 0) {
goto fail;
}
bs->backing_file[len] = '\0';
}
/* Disable migration when qcow images are used */
error_set(&s->migration_blocker,
QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
"qcow", bdrv_get_device_name(bs), "live migration");
migrate_add_blocker(s->migration_blocker);
qemu_co_mutex_init(&s->lock);
return 0;
fail:
g_free(s->l1_table);
qemu_vfree(s->l2_cache);
g_free(s->cluster_cache);
g_free(s->cluster_data);
return ret;
}
/* We have nothing to do for QCOW reopen, stubs just return
* success */
static int qcow_reopen_prepare(BDRVReopenState *state,
BlockReopenQueue *queue, Error **errp)
{
return 0;
}
static int qcow_set_key(BlockDriverState *bs, const char *key)
{
BDRVQcowState *s = bs->opaque;
uint8_t keybuf[16];
int len, i;
memset(keybuf, 0, 16);
len = strlen(key);
if (len > 16)
len = 16;
/* XXX: we could compress the chars to 7 bits to increase
entropy */
for(i = 0;i < len;i++) {
keybuf[i] = key[i];
}
s->crypt_method = s->crypt_method_header;
if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
return -1;
if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
return -1;
return 0;
}
/* The crypt function is compatible with the linux cryptoloop
algorithm for < 4 GB images. NOTE: out_buf == in_buf is
supported */
static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
uint8_t *out_buf, const uint8_t *in_buf,
int nb_sectors, int enc,
const AES_KEY *key)
{
union {
uint64_t ll[2];
uint8_t b[16];
} ivec;
int i;
for(i = 0; i < nb_sectors; i++) {
ivec.ll[0] = cpu_to_le64(sector_num);
ivec.ll[1] = 0;
AES_cbc_encrypt(in_buf, out_buf, 512, key,
ivec.b, enc);
sector_num++;
in_buf += 512;
out_buf += 512;
}
}
/* 'allocate' is:
*
* 0 to not allocate.
*
* 1 to allocate a normal cluster (for sector indexes 'n_start' to
* 'n_end')
*
* 2 to allocate a compressed cluster of size
* 'compressed_size'. 'compressed_size' must be > 0 and <
* cluster_size
*
* return 0 if not allocated.
*/
static uint64_t get_cluster_offset(BlockDriverState *bs,
uint64_t offset, int allocate,
int compressed_size,
int n_start, int n_end)
{
BDRVQcowState *s = bs->opaque;
int min_index, i, j, l1_index, l2_index;
uint64_t l2_offset, *l2_table, cluster_offset, tmp;
uint32_t min_count;
int new_l2_table;
l1_index = offset >> (s->l2_bits + s->cluster_bits);
l2_offset = s->l1_table[l1_index];
new_l2_table = 0;
if (!l2_offset) {
if (!allocate)
return 0;
/* allocate a new l2 entry */
l2_offset = bdrv_getlength(bs->file);
/* round to cluster size */
l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
/* update the L1 entry */
s->l1_table[l1_index] = l2_offset;
tmp = cpu_to_be64(l2_offset);
if (bdrv_pwrite_sync(bs->file,
s->l1_table_offset + l1_index * sizeof(tmp),
&tmp, sizeof(tmp)) < 0)
return 0;
new_l2_table = 1;
}
for(i = 0; i < L2_CACHE_SIZE; i++) {
if (l2_offset == s->l2_cache_offsets[i]) {
/* increment the hit count */
if (++s->l2_cache_counts[i] == 0xffffffff) {
for(j = 0; j < L2_CACHE_SIZE; j++) {
s->l2_cache_counts[j] >>= 1;
}
}
l2_table = s->l2_cache + (i << s->l2_bits);
goto found;
}
}
/* not found: load a new entry in the least used one */
min_index = 0;
min_count = 0xffffffff;
for(i = 0; i < L2_CACHE_SIZE; i++) {
if (s->l2_cache_counts[i] < min_count) {
min_count = s->l2_cache_counts[i];
min_index = i;
}
}
l2_table = s->l2_cache + (min_index << s->l2_bits);
if (new_l2_table) {
memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
s->l2_size * sizeof(uint64_t)) < 0)
return 0;
} else {
if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
s->l2_size * sizeof(uint64_t))
return 0;
}
s->l2_cache_offsets[min_index] = l2_offset;
s->l2_cache_counts[min_index] = 1;
found:
l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
cluster_offset = be64_to_cpu(l2_table[l2_index]);
if (!cluster_offset ||
((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
if (!allocate)
return 0;
/* allocate a new cluster */
if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
(n_end - n_start) < s->cluster_sectors) {
/* if the cluster is already compressed, we must
decompress it in the case it is not completely
overwritten */
if (decompress_cluster(bs, cluster_offset) < 0)
return 0;
cluster_offset = bdrv_getlength(bs->file);
cluster_offset = (cluster_offset + s->cluster_size - 1) &
~(s->cluster_size - 1);
/* write the cluster content */
if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) !=
s->cluster_size)
return -1;
} else {
cluster_offset = bdrv_getlength(bs->file);
if (allocate == 1) {
/* round to cluster size */
cluster_offset = (cluster_offset + s->cluster_size - 1) &
~(s->cluster_size - 1);
bdrv_truncate(bs->file, cluster_offset + s->cluster_size);
/* if encrypted, we must initialize the cluster
content which won't be written */
if (s->crypt_method &&
(n_end - n_start) < s->cluster_sectors) {
uint64_t start_sect;
start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
memset(s->cluster_data + 512, 0x00, 512);
for(i = 0; i < s->cluster_sectors; i++) {
if (i < n_start || i >= n_end) {
encrypt_sectors(s, start_sect + i,
s->cluster_data,
s->cluster_data + 512, 1, 1,
&s->aes_encrypt_key);
if (bdrv_pwrite(bs->file, cluster_offset + i * 512,
s->cluster_data, 512) != 512)
return -1;
}
}
}
} else if (allocate == 2) {
cluster_offset |= QCOW_OFLAG_COMPRESSED |
(uint64_t)compressed_size << (63 - s->cluster_bits);
}
}
/* update L2 table */
tmp = cpu_to_be64(cluster_offset);
l2_table[l2_index] = tmp;
if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
&tmp, sizeof(tmp)) < 0)
return 0;
}
return cluster_offset;
}
static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, int *pnum)
{
BDRVQcowState *s = bs->opaque;
int index_in_cluster, n;
uint64_t cluster_offset;
qemu_co_mutex_lock(&s->lock);
cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
qemu_co_mutex_unlock(&s->lock);
index_in_cluster = sector_num & (s->cluster_sectors - 1);
n = s->cluster_sectors - index_in_cluster;
if (n > nb_sectors)
n = nb_sectors;
*pnum = n;
if (!cluster_offset) {
return 0;
}
if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypt_method) {
return BDRV_BLOCK_DATA;
}
cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset;
}
static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
const uint8_t *buf, int buf_size)
{
z_stream strm1, *strm = &strm1;
int ret, out_len;
memset(strm, 0, sizeof(*strm));
strm->next_in = (uint8_t *)buf;
strm->avail_in = buf_size;
strm->next_out = out_buf;
strm->avail_out = out_buf_size;
ret = inflateInit2(strm, -12);
if (ret != Z_OK)
return -1;
ret = inflate(strm, Z_FINISH);
out_len = strm->next_out - out_buf;
if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
out_len != out_buf_size) {
inflateEnd(strm);
return -1;
}
inflateEnd(strm);
return 0;
}
static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
{
BDRVQcowState *s = bs->opaque;
int ret, csize;
uint64_t coffset;
coffset = cluster_offset & s->cluster_offset_mask;
if (s->cluster_cache_offset != coffset) {
csize = cluster_offset >> (63 - s->cluster_bits);
csize &= (s->cluster_size - 1);
ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
if (ret != csize)
return -1;
if (decompress_buffer(s->cluster_cache, s->cluster_size,
s->cluster_data, csize) < 0) {
return -1;
}
s->cluster_cache_offset = coffset;
}
return 0;
}
static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
BDRVQcowState *s = bs->opaque;
int index_in_cluster;
int ret = 0, n;
uint64_t cluster_offset;
struct iovec hd_iov;
QEMUIOVector hd_qiov;
uint8_t *buf;
void *orig_buf;
if (qiov->niov > 1) {
buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
if (buf == NULL) {
return -ENOMEM;
}
} else {
orig_buf = NULL;
buf = (uint8_t *)qiov->iov->iov_base;
}
qemu_co_mutex_lock(&s->lock);
while (nb_sectors != 0) {
/* prepare next request */
cluster_offset = get_cluster_offset(bs, sector_num << 9,
0, 0, 0, 0);
index_in_cluster = sector_num & (s->cluster_sectors - 1);
n = s->cluster_sectors - index_in_cluster;
if (n > nb_sectors) {
n = nb_sectors;
}
if (!cluster_offset) {
if (bs->backing_hd) {
/* read from the base image */
hd_iov.iov_base = (void *)buf;
hd_iov.iov_len = n * 512;
qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
qemu_co_mutex_unlock(&s->lock);
ret = bdrv_co_readv(bs->backing_hd, sector_num,
n, &hd_qiov);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
goto fail;
}
} else {
/* Note: in this case, no need to wait */
memset(buf, 0, 512 * n);
}
} else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
/* add AIO support for compressed blocks ? */
if (decompress_cluster(bs, cluster_offset) < 0) {
goto fail;
}
memcpy(buf,
s->cluster_cache + index_in_cluster * 512, 512 * n);
} else {
if ((cluster_offset & 511) != 0) {
goto fail;
}
hd_iov.iov_base = (void *)buf;
hd_iov.iov_len = n * 512;
qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
qemu_co_mutex_unlock(&s->lock);
ret = bdrv_co_readv(bs->file,
(cluster_offset >> 9) + index_in_cluster,
n, &hd_qiov);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
break;
}
if (s->crypt_method) {
encrypt_sectors(s, sector_num, buf, buf,
n, 0,
&s->aes_decrypt_key);
}
}
ret = 0;
nb_sectors -= n;
sector_num += n;
buf += n * 512;
}
done:
qemu_co_mutex_unlock(&s->lock);
if (qiov->niov > 1) {
qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
qemu_vfree(orig_buf);
}
return ret;
fail:
ret = -EIO;
goto done;
}
static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
BDRVQcowState *s = bs->opaque;
int index_in_cluster;
uint64_t cluster_offset;
const uint8_t *src_buf;
int ret = 0, n;
uint8_t *cluster_data = NULL;
struct iovec hd_iov;
QEMUIOVector hd_qiov;
uint8_t *buf;
void *orig_buf;
s->cluster_cache_offset = -1; /* disable compressed cache */
if (qiov->niov > 1) {
buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
if (buf == NULL) {
return -ENOMEM;
}
qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
} else {
orig_buf = NULL;
buf = (uint8_t *)qiov->iov->iov_base;
}
qemu_co_mutex_lock(&s->lock);
while (nb_sectors != 0) {
index_in_cluster = sector_num & (s->cluster_sectors - 1);
n = s->cluster_sectors - index_in_cluster;
if (n > nb_sectors) {
n = nb_sectors;
}
cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0,
index_in_cluster,
index_in_cluster + n);
if (!cluster_offset || (cluster_offset & 511) != 0) {
ret = -EIO;
break;
}
if (s->crypt_method) {
if (!cluster_data) {
cluster_data = g_malloc0(s->cluster_size);
}
encrypt_sectors(s, sector_num, cluster_data, buf,
n, 1, &s->aes_encrypt_key);
src_buf = cluster_data;
} else {
src_buf = buf;
}
hd_iov.iov_base = (void *)src_buf;
hd_iov.iov_len = n * 512;
qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
qemu_co_mutex_unlock(&s->lock);
ret = bdrv_co_writev(bs->file,
(cluster_offset >> 9) + index_in_cluster,
n, &hd_qiov);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
break;
}
ret = 0;
nb_sectors -= n;
sector_num += n;
buf += n * 512;
}
qemu_co_mutex_unlock(&s->lock);
if (qiov->niov > 1) {
qemu_vfree(orig_buf);
}
g_free(cluster_data);
return ret;
}
static void qcow_close(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
g_free(s->l1_table);
qemu_vfree(s->l2_cache);
g_free(s->cluster_cache);
g_free(s->cluster_data);
migrate_del_blocker(s->migration_blocker);
error_free(s->migration_blocker);
}
static int qcow_create(const char *filename, QemuOpts *opts, Error **errp)
{
int header_size, backing_filename_len, l1_size, shift, i;
QCowHeader header;
uint8_t *tmp;
int64_t total_size = 0;
char *backing_file = NULL;
int flags = 0;
Error *local_err = NULL;
int ret;
BlockDriverState *qcow_bs;
/* Read out options */
total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
BDRV_SECTOR_SIZE);
backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
flags |= BLOCK_FLAG_ENCRYPT;
}
ret = bdrv_create_file(filename, opts, &local_err);
if (ret < 0) {
error_propagate(errp, local_err);
goto cleanup;
}
qcow_bs = NULL;
ret = bdrv_open(&qcow_bs, filename, NULL, NULL,
BDRV_O_RDWR | BDRV_O_PROTOCOL, NULL, &local_err);
if (ret < 0) {
error_propagate(errp, local_err);
goto cleanup;
}
ret = bdrv_truncate(qcow_bs, 0);
if (ret < 0) {
goto exit;
}
memset(&header, 0, sizeof(header));
header.magic = cpu_to_be32(QCOW_MAGIC);
header.version = cpu_to_be32(QCOW_VERSION);
header.size = cpu_to_be64(total_size);
header_size = sizeof(header);
backing_filename_len = 0;
if (backing_file) {
if (strcmp(backing_file, "fat:")) {
header.backing_file_offset = cpu_to_be64(header_size);
backing_filename_len = strlen(backing_file);
header.backing_file_size = cpu_to_be32(backing_filename_len);
header_size += backing_filename_len;
} else {
/* special backing file for vvfat */
backing_file = NULL;
}
header.cluster_bits = 9; /* 512 byte cluster to avoid copying
unmodified sectors */
header.l2_bits = 12; /* 32 KB L2 tables */
} else {
header.cluster_bits = 12; /* 4 KB clusters */
header.l2_bits = 9; /* 4 KB L2 tables */
}
header_size = (header_size + 7) & ~7;
shift = header.cluster_bits + header.l2_bits;
l1_size = (total_size + (1LL << shift) - 1) >> shift;
header.l1_table_offset = cpu_to_be64(header_size);
if (flags & BLOCK_FLAG_ENCRYPT) {
header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
} else {
header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
}
/* write all the data */
ret = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header));
if (ret != sizeof(header)) {
goto exit;
}
if (backing_file) {
ret = bdrv_pwrite(qcow_bs, sizeof(header),
backing_file, backing_filename_len);
if (ret != backing_filename_len) {
goto exit;
}
}
tmp = g_malloc0(BDRV_SECTOR_SIZE);
for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/
BDRV_SECTOR_SIZE); i++) {
ret = bdrv_pwrite(qcow_bs, header_size +
BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE);
if (ret != BDRV_SECTOR_SIZE) {
g_free(tmp);
goto exit;
}
}
g_free(tmp);
ret = 0;
exit:
bdrv_unref(qcow_bs);
cleanup:
g_free(backing_file);
return ret;
}
static int qcow_make_empty(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
uint32_t l1_length = s->l1_size * sizeof(uint64_t);
int ret;
memset(s->l1_table, 0, l1_length);
if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table,
l1_length) < 0)
return -1;
ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length);
if (ret < 0)
return ret;
memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
return 0;
}
/* XXX: put compressed sectors first, then all the cluster aligned
tables to avoid losing bytes in alignment */
static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors)
{
BDRVQcowState *s = bs->opaque;
z_stream strm;
int ret, out_len;
uint8_t *out_buf;
uint64_t cluster_offset;
if (nb_sectors != s->cluster_sectors) {
ret = -EINVAL;
/* Zero-pad last write if image size is not cluster aligned */
if (sector_num + nb_sectors == bs->total_sectors &&
nb_sectors < s->cluster_sectors) {
uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size);
memset(pad_buf, 0, s->cluster_size);
memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE);
ret = qcow_write_compressed(bs, sector_num,
pad_buf, s->cluster_sectors);
qemu_vfree(pad_buf);
}
return ret;
}
out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
/* best compression, small window, no zlib header */
memset(&strm, 0, sizeof(strm));
ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
Z_DEFLATED, -12,
9, Z_DEFAULT_STRATEGY);
if (ret != 0) {
ret = -EINVAL;
goto fail;
}
strm.avail_in = s->cluster_size;
strm.next_in = (uint8_t *)buf;
strm.avail_out = s->cluster_size;
strm.next_out = out_buf;
ret = deflate(&strm, Z_FINISH);
if (ret != Z_STREAM_END && ret != Z_OK) {
deflateEnd(&strm);
ret = -EINVAL;
goto fail;
}
out_len = strm.next_out - out_buf;
deflateEnd(&strm);
if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
/* could not compress: write normal cluster */
ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors);
if (ret < 0) {
goto fail;
}
} else {
cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
out_len, 0, 0);
if (cluster_offset == 0) {
ret = -EIO;
goto fail;
}
cluster_offset &= s->cluster_offset_mask;
ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len);
if (ret < 0) {
goto fail;
}
}
ret = 0;
fail:
g_free(out_buf);
return ret;
}
static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
BDRVQcowState *s = bs->opaque;
bdi->cluster_size = s->cluster_size;
return 0;
}
static QemuOptsList qcow_create_opts = {
.name = "qcow-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size"
},
{
.name = BLOCK_OPT_BACKING_FILE,
.type = QEMU_OPT_STRING,
.help = "File name of a base image"
},
{
.name = BLOCK_OPT_ENCRYPT,
.type = QEMU_OPT_BOOL,
.help = "Encrypt the image",
.def_value_str = "off"
},
{ /* end of list */ }
}
};
static BlockDriver bdrv_qcow = {
.format_name = "qcow",
.instance_size = sizeof(BDRVQcowState),
.bdrv_probe = qcow_probe,
.bdrv_open = qcow_open,
.bdrv_close = qcow_close,
.bdrv_reopen_prepare = qcow_reopen_prepare,
.bdrv_create = qcow_create,
.bdrv_has_zero_init = bdrv_has_zero_init_1,
.supports_backing = true,
.bdrv_co_readv = qcow_co_readv,
.bdrv_co_writev = qcow_co_writev,
.bdrv_co_get_block_status = qcow_co_get_block_status,
.bdrv_set_key = qcow_set_key,
.bdrv_make_empty = qcow_make_empty,
.bdrv_write_compressed = qcow_write_compressed,
.bdrv_get_info = qcow_get_info,
.create_opts = &qcow_create_opts,
};
static void bdrv_qcow_init(void)
{
bdrv_register(&bdrv_qcow);
}
block_init(bdrv_qcow_init);
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