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block-vpc: Adapt header structures to official documentation (Kevin Wolf) 

The current definition of the VirtualPC headers is incomplete and partly
even wrong. This patch changes the header structs according to the
official VHD specification.

Signed-off-by: Kevin Wolf <kwolf@suse.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6455 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori 2009-01-26 20:26:49 +00:00
parent b9fa33a6e4
commit 2cfacb6293
1 changed files with 82 additions and 36 deletions
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118
block-vpc.c
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@ -30,41 +30,87 @@
//#define CACHE
enum vhd_type {
VHD_FIXED = 2,
VHD_DYNAMIC = 3,
VHD_DIFFERENCING = 4,
};
// always big-endian
struct vhd_footer {
char creator[8]; // "conectix
uint32_t unk1[2];
uint32_t unk2; // always zero?
uint32_t subheader_offset;
uint32_t unk3; // some size?
char creator_app[4]; // "vpc "
uint16_t major;
uint16_t minor;
char guest[4]; // "Wi2k"
uint32_t unk4[7];
uint8_t vnet_id[16]; // virtual network id, purpose unknown
// next 16 longs are used, but dunno the purpose
// next 6 longs unknown, following 7 long maybe a serial
char creator[8]; // "conectix"
uint32_t features;
uint32_t version;
// Offset of next header structure, 0xFFFFFFFF if none
uint64_t data_offset;
// Seconds since Jan 1, 2000 0:00:00 (UTC)
uint32_t timestamp;
char creator_app[4]; // "vpc "
uint16_t major;
uint16_t minor;
char creator_os[4]; // "Wi2k"
uint64_t orig_size;
uint64_t size;
uint16_t cyls;
uint8_t heads;
uint8_t secs_per_cyl;
uint32_t type;
// Checksum of the Hard Disk Footer ("one's complement of the sum of all
// the bytes in the footer without the checksum field")
uint32_t checksum;
// UUID used to identify a parent hard disk (backing file)
uint8_t uuid[16];
uint8_t in_saved_state;
};
struct vhd_dyndisk_header {
char magic[8]; // "cxsparse"
uint32_t unk1[2]; // all bits set
uint32_t unk2; // always zero?
uint32_t pagetable_offset;
uint32_t unk3;
uint32_t pagetable_entries; // 32bit/entry
uint32_t pageentry_size; // 512*8*512
uint32_t nb_sectors;
char magic[8]; // "cxsparse"
// Offset of next header structure, 0xFFFFFFFF if none
uint64_t data_offset;
// Offset of the Block Allocation Table (BAT)
uint64_t table_offset;
uint32_t version;
uint32_t max_table_entries; // 32bit/entry
// 2 MB by default, must be a power of two
uint32_t block_size;
uint32_t checksum;
uint8_t parent_uuid[16];
uint32_t parent_timestamp;
uint32_t reserved;
// Backing file name (in UTF-16)
uint8_t parent_name[512];
struct {
uint32_t platform;
uint32_t data_space;
uint32_t data_length;
uint32_t reserved;
uint64_t data_offset;
} parent_locator[8];
};
typedef struct BDRVVPCState {
int fd;
int pagetable_entries;
int max_table_entries;
uint32_t *pagetable;
uint32_t pageentry_size;
uint32_t block_size;
#ifdef CACHE
uint8_t *pageentry_u8;
uint32_t *pageentry_u32;
@ -104,7 +150,7 @@ static int vpc_open(BlockDriverState *bs, const char *filename, int flags)
if (strncmp(footer->creator, "conectix", 8))
goto fail;
lseek(s->fd, be32_to_cpu(footer->subheader_offset), SEEK_SET);
lseek(s->fd, be64_to_cpu(footer->data_offset), SEEK_SET);
if (read(fd, buf, HEADER_SIZE) != HEADER_SIZE)
goto fail;
@ -114,22 +160,22 @@ static int vpc_open(BlockDriverState *bs, const char *filename, int flags)
if (strncmp(dyndisk_header->magic, "cxsparse", 8))
goto fail;
bs->total_sectors = ((uint64_t)be32_to_cpu(dyndisk_header->pagetable_entries) *
be32_to_cpu(dyndisk_header->pageentry_size)) / 512;
bs->total_sectors = ((uint64_t)be32_to_cpu(dyndisk_header->max_table_entries) *
be32_to_cpu(dyndisk_header->block_size)) / 512;
lseek(s->fd, be32_to_cpu(dyndisk_header->pagetable_offset), SEEK_SET);
lseek(s->fd, be64_to_cpu(dyndisk_header->table_offset), SEEK_SET);
s->pagetable_entries = be32_to_cpu(dyndisk_header->pagetable_entries);
s->pagetable = qemu_malloc(s->pagetable_entries * 4);
s->max_table_entries = be32_to_cpu(dyndisk_header->max_table_entries);
s->pagetable = qemu_malloc(s->max_table_entries * 4);
if (!s->pagetable)
goto fail;
if (read(s->fd, s->pagetable, s->pagetable_entries * 4) !=
s->pagetable_entries * 4)
if (read(s->fd, s->pagetable, s->max_table_entries * 4) !=
s->max_table_entries * 4)
goto fail;
for (i = 0; i < s->pagetable_entries; i++)
for (i = 0; i < s->max_table_entries; i++)
be32_to_cpus(&s->pagetable[i]);
s->pageentry_size = be32_to_cpu(dyndisk_header->pageentry_size);
s->block_size = be32_to_cpu(dyndisk_header->block_size);
#ifdef CACHE
s->pageentry_u8 = qemu_malloc(512);
if (!s->pageentry_u8)
@ -152,10 +198,10 @@ static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num)
uint64_t bitmap_offset, block_offset;
uint32_t pagetable_index, pageentry_index;
pagetable_index = offset / s->pageentry_size;
pageentry_index = (offset % s->pageentry_size) / 512;
pagetable_index = offset / s->block_size;
pageentry_index = (offset % s->block_size) / 512;
if (pagetable_index > s->pagetable_entries || s->pagetable[pagetable_index] == 0xffffffff)
if (pagetable_index > s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff)
return -1; // not allocated
bitmap_offset = 512 * s->pagetable[pagetable_index];