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/*
* Block driver for the various disk image formats used by Bochs
* Currently only for "growing" type in read-only mode
*
* Copyright (c) 2005 Alex Beregszaszi
*
* 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"
/**************************************************************/
#define HEADER_MAGIC "Bochs Virtual HD Image"
#define HEADER_VERSION 0x00010000
#define HEADER_SIZE 512
#define REDOLOG_TYPE "Redolog"
#define GROWING_TYPE "Growing"
// not allocated: 0xffffffff
// always little-endian
struct bochs_header {
char magic[32]; // "Bochs Virtual HD Image"
char type[16]; // "Redolog"
char subtype[16]; // "Undoable" / "Volatile" / "Growing"
uint32_t version;
uint32_t header; // size of header
union {
struct {
uint32_t catalog; // num of entries
uint32_t bitmap; // bitmap size
uint32_t extent; // extent size
uint64_t disk; // disk size
char padding[HEADER_SIZE - 64 - 8 - 20];
} redolog;
char padding[HEADER_SIZE - 64 - 8];
} extra;
};
typedef struct BDRVBochsState {
int fd;
uint32_t *catalog_bitmap;
int catalog_size;
int data_offset;
int bitmap_blocks;
int extent_blocks;
int extent_size;
} BDRVBochsState;
static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
{
const struct bochs_header *bochs = (const void *)buf;
if (buf_size < HEADER_SIZE)
return 0;
if (!strcmp(bochs->magic, HEADER_MAGIC) &&
!strcmp(bochs->type, REDOLOG_TYPE) &&
!strcmp(bochs->subtype, GROWING_TYPE) &&
(le32_to_cpu(bochs->version) == HEADER_VERSION))
return 100;
return 0;
}
static int bochs_open(BlockDriverState *bs, const char *filename, int flags)
{
BDRVBochsState *s = bs->opaque;
int fd, i;
struct bochs_header bochs;
fd = open(filename, O_RDWR | O_BINARY);
if (fd < 0) {
fd = open(filename, O_RDONLY | O_BINARY);
if (fd < 0)
return -1;
}
bs->read_only = 1; // no write support yet
s->fd = fd;
if (read(fd, &bochs, sizeof(bochs)) != sizeof(bochs)) {
goto fail;
}
if (strcmp(bochs.magic, HEADER_MAGIC) ||
strcmp(bochs.type, REDOLOG_TYPE) ||
strcmp(bochs.subtype, GROWING_TYPE) ||
(le32_to_cpu(bochs.version) != HEADER_VERSION)) {
goto fail;
}
bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512;
lseek(s->fd, le32_to_cpu(bochs.header), SEEK_SET);
s->catalog_size = le32_to_cpu(bochs.extra.redolog.catalog);
s->catalog_bitmap = qemu_malloc(s->catalog_size * 4);
if (!s->catalog_bitmap)
goto fail;
if (read(s->fd, s->catalog_bitmap, s->catalog_size * 4) !=
s->catalog_size * 4)
goto fail;
for (i = 0; i < s->catalog_size; i++)
le32_to_cpus(&s->catalog_bitmap[i]);
s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4);
s->bitmap_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.bitmap) - 1) / 512;
s->extent_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.extent) - 1) / 512;
s->extent_size = le32_to_cpu(bochs.extra.redolog.extent);
return 0;
fail:
close(fd);
return -1;
}
static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num)
{
BDRVBochsState *s = bs->opaque;
int64_t offset = sector_num * 512;
int64_t extent_index, extent_offset, bitmap_offset, block_offset;
char bitmap_entry;
// seek to sector
extent_index = offset / s->extent_size;
extent_offset = (offset % s->extent_size) / 512;
if (s->catalog_bitmap[extent_index] == 0xffffffff)
{
// fprintf(stderr, "page not allocated [%x - %x:%x]\n",
// sector_num, extent_index, extent_offset);
return -1; // not allocated
}
bitmap_offset = s->data_offset + (512 * s->catalog_bitmap[extent_index] *
(s->extent_blocks + s->bitmap_blocks));
block_offset = bitmap_offset + (512 * (s->bitmap_blocks + extent_offset));
// fprintf(stderr, "sect: %x [ext i: %x o: %x] -> %x bitmap: %x block: %x\n",
// sector_num, extent_index, extent_offset,
// le32_to_cpu(s->catalog_bitmap[extent_index]),
// bitmap_offset, block_offset);
// read in bitmap for current extent
lseek(s->fd, bitmap_offset + (extent_offset / 8), SEEK_SET);
read(s->fd, &bitmap_entry, 1);
if (!((bitmap_entry >> (extent_offset % 8)) & 1))
{
// fprintf(stderr, "sector (%x) in bitmap not allocated\n",
// sector_num);
return -1; // not allocated
}
lseek(s->fd, block_offset, SEEK_SET);
return 0;
}
static int bochs_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
BDRVBochsState *s = bs->opaque;
int ret;
while (nb_sectors > 0) {
if (!seek_to_sector(bs, sector_num))
{
ret = read(s->fd, buf, 512);
if (ret != 512)
return -1;
}
else
memset(buf, 0, 512);
nb_sectors--;
sector_num++;
buf += 512;
}
return 0;
}
static void bochs_close(BlockDriverState *bs)
{
BDRVBochsState *s = bs->opaque;
qemu_free(s->catalog_bitmap);
close(s->fd);
}
BlockDriver bdrv_bochs = {
"bochs",
sizeof(BDRVBochsState),
bochs_probe,
bochs_open,
bochs_read,
NULL,
bochs_close,
};
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