block-vmdk.c
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/*
* Block driver for the VMDK format
*
* Copyright (c) 2004 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 "vl.h"
#include "block_int.h"
/* XXX: this code is untested */
/* XXX: add write support */
#define VMDK3_MAGIC (('C' << 24) | ('O' << 16) | ('W' << 8) | 'D')
#define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V')
typedef struct {
uint32_t version;
uint32_t flags;
uint32_t disk_sectors;
uint32_t granularity;
uint32_t l1dir_offset;
uint32_t l1dir_size;
uint32_t file_sectors;
uint32_t cylinders;
uint32_t heads;
uint32_t sectors_per_track;
} VMDK3Header;
typedef struct {
uint32_t version;
uint32_t flags;
int64_t capacity;
int64_t granularity;
int64_t desc_offset;
int64_t desc_size;
int32_t num_gtes_per_gte;
int64_t rgd_offset;
int64_t gd_offset;
int64_t grain_offset;
char filler[1];
char check_bytes[4];
} VMDK4Header;
#define L2_CACHE_SIZE 16
typedef struct BDRVVmdkState {
int fd;
int64_t l1_table_offset;
uint32_t *l1_table;
unsigned int l1_size;
uint32_t l1_entry_sectors;
unsigned int l2_size;
uint32_t *l2_cache;
uint32_t l2_cache_offsets[L2_CACHE_SIZE];
uint32_t l2_cache_counts[L2_CACHE_SIZE];
unsigned int cluster_sectors;
} BDRVVmdkState;
static int vmdk_probe(const uint8_t *buf, int buf_size, const char *filename)
{
uint32_t magic;
if (buf_size < 4)
return 0;
magic = be32_to_cpu(*(uint32_t *)buf);
if (magic == VMDK3_MAGIC ||
magic == VMDK4_MAGIC)
return 100;
else
return 0;
}
static int vmdk_open(BlockDriverState *bs, const char *filename)
{
BDRVVmdkState *s = bs->opaque;
int fd, i;
uint32_t magic;
int l1_size;
fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
if (fd < 0)
return -1;
if (read(fd, &magic, sizeof(magic)) != sizeof(magic))
goto fail;
magic = be32_to_cpu(magic);
if (magic == VMDK3_MAGIC) {
VMDK3Header header;
if (read(fd, &header, sizeof(header)) !=
sizeof(header))
goto fail;
s->cluster_sectors = le32_to_cpu(header.granularity);
s->l2_size = 1 << 9;
s->l1_size = 1 << 6;
bs->total_sectors = le32_to_cpu(header.disk_sectors);
s->l1_table_offset = le32_to_cpu(header.l1dir_offset) * 512;
s->l1_entry_sectors = s->l2_size * s->cluster_sectors;
} else if (magic == VMDK4_MAGIC) {
VMDK4Header header;
if (read(fd, &header, sizeof(header)) != sizeof(header))
goto fail;
bs->total_sectors = le32_to_cpu(header.capacity);
s->cluster_sectors = le32_to_cpu(header.granularity);
s->l2_size = le32_to_cpu(header.num_gtes_per_gte);
s->l1_entry_sectors = s->l2_size * s->cluster_sectors;
if (s->l1_entry_sectors <= 0)
goto fail;
s->l1_size = (bs->total_sectors + s->l1_entry_sectors - 1)
/ s->l1_entry_sectors;
s->l1_table_offset = le64_to_cpu(header.rgd_offset) * 512;
} else {
goto fail;
}
/* read the L1 table */
l1_size = s->l1_size * sizeof(uint32_t);
s->l1_table = qemu_malloc(l1_size);
if (!s->l1_table)
goto fail;
if (lseek(fd, s->l1_table_offset, SEEK_SET) == -1)
goto fail;
if (read(fd, s->l1_table, l1_size) != l1_size)
goto fail;
for(i = 0; i < s->l1_size; i++) {
le32_to_cpus(&s->l1_table[i]);
}
s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint32_t));
if (!s->l2_cache)
goto fail;
s->fd = fd;
/* XXX: currently only read only */
bs->read_only = 1;
return 0;
fail:
qemu_free(s->l1_table);
qemu_free(s->l2_cache);
close(fd);
return -1;
}
static uint64_t get_cluster_offset(BlockDriverState *bs,
uint64_t offset)
{
BDRVVmdkState *s = bs->opaque;
unsigned int l1_index, l2_offset, l2_index;
int min_index, i, j;
uint32_t min_count, *l2_table;
uint64_t cluster_offset;
l1_index = (offset >> 9) / s->l1_entry_sectors;
if (l1_index >= s->l1_size)
return 0;
l2_offset = s->l1_table[l1_index];
if (!l2_offset)
return 0;
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_size);
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_size);
lseek(s->fd, (int64_t)l2_offset * 512, SEEK_SET);
if (read(s->fd, l2_table, s->l2_size * sizeof(uint32_t)) !=
s->l2_size * sizeof(uint32_t))
return 0;
s->l2_cache_offsets[min_index] = l2_offset;
s->l2_cache_counts[min_index] = 1;
found:
l2_index = ((offset >> 9) / s->cluster_sectors) % s->l2_size;
cluster_offset = le32_to_cpu(l2_table[l2_index]);
cluster_offset <<= 9;
return cluster_offset;
}
static int vmdk_is_allocated(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int *pnum)
{
BDRVVmdkState *s = bs->opaque;
int index_in_cluster, n;
uint64_t cluster_offset;
cluster_offset = get_cluster_offset(bs, sector_num << 9);
index_in_cluster = sector_num % s->cluster_sectors;
n = s->cluster_sectors - index_in_cluster;
if (n > nb_sectors)
n = nb_sectors;
*pnum = n;
return (cluster_offset != 0);
}
static int vmdk_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
BDRVVmdkState *s = bs->opaque;
int ret, index_in_cluster, n;
uint64_t cluster_offset;
while (nb_sectors > 0) {
cluster_offset = get_cluster_offset(bs, sector_num << 9);
index_in_cluster = sector_num % s->cluster_sectors;
n = s->cluster_sectors - index_in_cluster;
if (n > nb_sectors)
n = nb_sectors;
if (!cluster_offset) {
memset(buf, 0, 512 * n);
} else {
lseek(s->fd, cluster_offset + index_in_cluster * 512, SEEK_SET);
ret = read(s->fd, buf, n * 512);
if (ret != n * 512)
return -1;
}
nb_sectors -= n;
sector_num += n;
buf += n * 512;
}
return 0;
}
static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors)
{
return -1;
}
static int vmdk_close(BlockDriverState *bs)
{
BDRVVmdkState *s = bs->opaque;
qemu_free(s->l1_table);
qemu_free(s->l2_cache);
close(s->fd);
}
BlockDriver bdrv_vmdk = {
"vmdk",
sizeof(BDRVVmdkState),
vmdk_probe,
vmdk_open,
vmdk_read,
vmdk_write,
vmdk_close,
NULL, /* no create yet */
vmdk_is_allocated,
};