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block/vpc: Pad VHDDynDiskHeader, replace uint8_t[] buffers

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Pad VHDDynDiskHeader as specified in the "Virtual Hard Disk Image
Format Specification" version 1.0[*].  Change dynamic disk header
buffers from uint8_t[1024] to VHDDynDiskHeader.  Their size remains
the same.

The VHDDynDiskHeader * variables pointing to a VHDDynDiskHeader
variable right next to it are now silly.  Eliminate them.

[*] http://download.microsoft.com/download/f/f/e/ffef50a5-07dd-4cf8-aaa3-442c0673a029/Virtual%20Hard%20Disk%20Format%20Spec_10_18_06.doc

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20201217162003.1102738-6-armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Markus Armbruster 2020-12-17 17:19:59 +01:00 committed by Kevin Wolf
parent 7550379ded
commit e326f0783e
1 changed files with 19 additions and 22 deletions
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41
block/vpc.c
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@ -127,8 +127,11 @@ typedef struct vhd_dyndisk_header {
uint32_t reserved;
uint64_t data_offset;
} parent_locator[8];
uint8_t reserved2[256];
} QEMU_PACKED VHDDynDiskHeader;
QEMU_BUILD_BUG_ON(sizeof(VHDDynDiskHeader) != 1024);
typedef struct BDRVVPCState {
CoMutex lock;
uint8_t footer_buf[HEADER_SIZE];
@ -217,11 +220,10 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
BDRVVPCState *s = bs->opaque;
int i;
VHDFooter *footer;
VHDDynDiskHeader *dyndisk_header;
QemuOpts *opts = NULL;
Error *local_err = NULL;
bool use_chs;
uint8_t dyndisk_header_buf[1024];
VHDDynDiskHeader dyndisk_header;
uint32_t checksum;
uint64_t computed_size;
uint64_t pagetable_size;
@ -342,21 +344,19 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
if (disk_type == VHD_DYNAMIC) {
ret = bdrv_pread(bs->file, be64_to_cpu(footer->data_offset),
dyndisk_header_buf, 1024);
&dyndisk_header, 1024);
if (ret < 0) {
error_setg(errp, "Error reading dynamic VHD header");
goto fail;
}
dyndisk_header = (VHDDynDiskHeader *)dyndisk_header_buf;
if (strncmp(dyndisk_header->magic, "cxsparse", 8)) {
if (strncmp(dyndisk_header.magic, "cxsparse", 8)) {
error_setg(errp, "Invalid header magic");
ret = -EINVAL;
goto fail;
}
s->block_size = be32_to_cpu(dyndisk_header->block_size);
s->block_size = be32_to_cpu(dyndisk_header.block_size);
if (!is_power_of_2(s->block_size) || s->block_size < BDRV_SECTOR_SIZE) {
error_setg(errp, "Invalid block size %" PRIu32, s->block_size);
ret = -EINVAL;
@ -364,7 +364,7 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
}
s->bitmap_size = ((s->block_size / (8 * 512)) + 511) & ~511;
s->max_table_entries = be32_to_cpu(dyndisk_header->max_table_entries);
s->max_table_entries = be32_to_cpu(dyndisk_header.max_table_entries);
if ((bs->total_sectors * 512) / s->block_size > 0xffffffffU) {
error_setg(errp, "Too many blocks");
@ -396,7 +396,7 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
goto fail;
}
s->bat_offset = be64_to_cpu(dyndisk_header->table_offset);
s->bat_offset = be64_to_cpu(dyndisk_header.table_offset);
ret = bdrv_pread(bs->file, s->bat_offset, s->pagetable,
pagetable_size);
@ -823,9 +823,7 @@ static int calculate_geometry(int64_t total_sectors, uint16_t *cyls,
static int create_dynamic_disk(BlockBackend *blk, uint8_t *buf,
int64_t total_sectors)
{
uint8_t dyndisk_header_buf[1024];
VHDDynDiskHeader *dyndisk_header =
(VHDDynDiskHeader *)dyndisk_header_buf;
VHDDynDiskHeader dyndisk_header;
uint8_t bat_sector[512];
size_t block_size, num_bat_entries;
int i;
@ -860,27 +858,26 @@ static int create_dynamic_disk(BlockBackend *blk, uint8_t *buf,
}
/* Prepare the Dynamic Disk Header */
memset(dyndisk_header_buf, 0, 1024);
memset(&dyndisk_header, 0, 1024);
memcpy(dyndisk_header->magic, "cxsparse", 8);
memcpy(dyndisk_header.magic, "cxsparse", 8);
/*
* Note: The spec is actually wrong here for data_offset, it says
* 0xFFFFFFFF, but MS tools expect all 64 bits to be set.
*/
dyndisk_header->data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL);
dyndisk_header->table_offset = cpu_to_be64(3 * 512);
dyndisk_header->version = cpu_to_be32(0x00010000);
dyndisk_header->block_size = cpu_to_be32(block_size);
dyndisk_header->max_table_entries = cpu_to_be32(num_bat_entries);
dyndisk_header.data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL);
dyndisk_header.table_offset = cpu_to_be64(3 * 512);
dyndisk_header.version = cpu_to_be32(0x00010000);
dyndisk_header.block_size = cpu_to_be32(block_size);
dyndisk_header.max_table_entries = cpu_to_be32(num_bat_entries);
dyndisk_header->checksum = cpu_to_be32(vpc_checksum(dyndisk_header_buf,
1024));
dyndisk_header.checksum = cpu_to_be32(vpc_checksum(&dyndisk_header, 1024));
/* Write the header */
offset = 512;
ret = blk_pwrite(blk, offset, dyndisk_header_buf, 1024, 0);
ret = blk_pwrite(blk, offset, &dyndisk_header, 1024, 0);
if (ret < 0) {
goto fail;
}