VHD_DIFFERENCING = 4,
};
+// Seconds since Jan 1, 2000 0:00:00 (UTC)
+#define VHD_TIMESTAMP_BASE 946684800
+
// always big-endian
struct vhd_footer {
char creator[8]; // "conectix"
#endif
} BDRVVPCState;
+static uint32_t vpc_checksum(uint8_t* buf, size_t size)
+{
+ uint32_t res = 0;
+ int i;
+
+ for (i = 0; i < size; i++)
+ res += buf[i];
+
+ return ~res;
+}
+
+
static int vpc_probe(const uint8_t *buf, int buf_size, const char *filename)
{
if (buf_size >= 8 && !strncmp((char *)buf, "conectix", 8))
struct vhd_footer* footer;
struct vhd_dyndisk_header* dyndisk_header;
uint8_t buf[HEADER_SIZE];
+ uint32_t checksum;
ret = bdrv_file_open(&s->hd, filename, flags);
if (ret < 0)
if (strncmp(footer->creator, "conectix", 8))
goto fail;
+ checksum = be32_to_cpu(footer->checksum);
+ footer->checksum = 0;
+ if (vpc_checksum(s->footer_buf, HEADER_SIZE) != checksum)
+ fprintf(stderr, "block-vpc: The header checksum of '%s' is "
+ "incorrect.\n", filename);
+
// The visible size of a image in Virtual PC depends on the geometry
// rather than on the size stored in the footer (the size in the footer
// is too large usually)
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;
s->bat_offset = be64_to_cpu(dyndisk_header->table_offset);
if (bdrv_pread(s->hd, s->bat_offset, s->pagetable,
#ifdef CACHE
s->pageentry_u8 = qemu_malloc(512);
- if (!s->pageentry_u8)
- goto fail;
s->pageentry_u32 = s->pageentry_u8;
s->pageentry_u16 = s->pageentry_u8;
s->last_pagetable = -1;
if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff)
return -1; // not allocated
- bitmap_offset = 512 * s->pagetable[pagetable_index];
+ bitmap_offset = 512 * (uint64_t) s->pagetable[pagetable_index];
block_offset = bitmap_offset + s->bitmap_size + (512 * pageentry_index);
// We must ensure that we don't write to any sectors which are marked as
return 0;
}
+
+/*
+ * Calculates the number of cylinders, heads and sectors per cylinder
+ * based on a given number of sectors. This is the algorithm described
+ * in the VHD specification.
+ *
+ * Note that the geometry doesn't always exactly match total_sectors but
+ * may round it down.
+ */
+static void calculate_geometry(int64_t total_sectors, uint16_t* cyls,
+ uint8_t* heads, uint8_t* secs_per_cyl)
+{
+ uint32_t cyls_times_heads;
+
+ if (total_sectors > 65535 * 16 * 255)
+ total_sectors = 65535 * 16 * 255;
+
+ if (total_sectors > 65535 * 16 * 63) {
+ *secs_per_cyl = 255;
+ *heads = 16;
+ cyls_times_heads = total_sectors / *secs_per_cyl;
+ } else {
+ *secs_per_cyl = 17;
+ cyls_times_heads = total_sectors / *secs_per_cyl;
+ *heads = (cyls_times_heads + 1023) / 1024;
+
+ if (*heads < 4)
+ *heads = 4;
+
+ if (cyls_times_heads >= (*heads * 1024) || *heads > 16) {
+ *secs_per_cyl = 31;
+ *heads = 16;
+ cyls_times_heads = total_sectors / *secs_per_cyl;
+ }
+
+ if (cyls_times_heads >= (*heads * 1024)) {
+ *secs_per_cyl = 63;
+ *heads = 16;
+ cyls_times_heads = total_sectors / *secs_per_cyl;
+ }
+ }
+
+ // Note: Rounding up deviates from the Virtual PC behaviour
+ // However, we need this to avoid truncating images in qemu-img convert
+ *cyls = (cyls_times_heads + *heads - 1) / *heads;
+}
+
+static int vpc_create(const char *filename, int64_t total_sectors,
+ const char *backing_file, int flags)
+{
+ uint8_t buf[1024];
+ struct vhd_footer* footer = (struct vhd_footer*) buf;
+ struct vhd_dyndisk_header* dyndisk_header =
+ (struct vhd_dyndisk_header*) buf;
+ int fd, i;
+ uint16_t cyls;
+ uint8_t heads;
+ uint8_t secs_per_cyl;
+ size_t block_size, num_bat_entries;
+
+ if (backing_file != NULL)
+ return -ENOTSUP;
+
+ fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
+ if (fd < 0)
+ return -EIO;
+
+ // Calculate matching total_size and geometry
+ calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl);
+ total_sectors = (int64_t) cyls * heads * secs_per_cyl;
+
+ // Prepare the Hard Disk Footer
+ memset(buf, 0, 1024);
+
+ strncpy(footer->creator, "conectix", 8);
+ // TODO Check if "qemu" creator_app is ok for VPC
+ strncpy(footer->creator_app, "qemu", 4);
+ strncpy(footer->creator_os, "Wi2k", 4);
+
+ footer->features = be32_to_cpu(0x02);
+ footer->version = be32_to_cpu(0x00010000);
+ footer->data_offset = be64_to_cpu(HEADER_SIZE);
+ footer->timestamp = be32_to_cpu(time(NULL) - VHD_TIMESTAMP_BASE);
+
+ // Version of Virtual PC 2007
+ footer->major = be16_to_cpu(0x0005);
+ footer->minor =be16_to_cpu(0x0003);
+
+ footer->orig_size = be64_to_cpu(total_sectors * 512);
+ footer->size = be64_to_cpu(total_sectors * 512);
+
+ footer->cyls = be16_to_cpu(cyls);
+ footer->heads = heads;
+ footer->secs_per_cyl = secs_per_cyl;
+
+ footer->type = be32_to_cpu(VHD_DYNAMIC);
+
+ // TODO uuid is missing
+
+ footer->checksum = be32_to_cpu(vpc_checksum(buf, HEADER_SIZE));
+
+ // Write the footer (twice: at the beginning and at the end)
+ block_size = 0x200000;
+ num_bat_entries = (total_sectors + block_size / 512) / (block_size / 512);
+
+ if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE)
+ return -EIO;
+
+ if (lseek(fd, 1536 + ((num_bat_entries * 4 + 511) & ~511), SEEK_SET) < 0)
+ return -EIO;
+ if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE)
+ return -EIO;
+
+ // Write the initial BAT
+ if (lseek(fd, 3 * 512, SEEK_SET) < 0)
+ return -EIO;
+
+ memset(buf, 0xFF, 512);
+ for (i = 0; i < (num_bat_entries * 4 + 511) / 512; i++)
+ if (write(fd, buf, 512) != 512)
+ return -EIO;
+
+
+ // Prepare the Dynamic Disk Header
+ memset(buf, 0, 1024);
+
+ strncpy(dyndisk_header->magic, "cxsparse", 8);
+
+ dyndisk_header->data_offset = be64_to_cpu(0xFFFFFFFF);
+ dyndisk_header->table_offset = be64_to_cpu(3 * 512);
+ dyndisk_header->version = be32_to_cpu(0x00010000);
+ dyndisk_header->block_size = be32_to_cpu(block_size);
+ dyndisk_header->max_table_entries = be32_to_cpu(num_bat_entries);
+
+ dyndisk_header->checksum = be32_to_cpu(vpc_checksum(buf, 1024));
+
+ // Write the header
+ if (lseek(fd, 512, SEEK_SET) < 0)
+ return -EIO;
+ if (write(fd, buf, 1024) != 1024)
+ return -EIO;
+
+ close(fd);
+ return 0;
+}
+
static void vpc_close(BlockDriverState *bs)
{
BDRVVPCState *s = bs->opaque;
}
BlockDriver bdrv_vpc = {
- "vpc",
- sizeof(BDRVVPCState),
- vpc_probe,
- vpc_open,
- vpc_read,
- vpc_write,
- vpc_close,
+ .format_name = "vpc",
+ .instance_size = sizeof(BDRVVPCState),
+ .bdrv_probe = vpc_probe,
+ .bdrv_open = vpc_open,
+ .bdrv_read = vpc_read,
+ .bdrv_write = vpc_write,
+ .bdrv_close = vpc_close,
+ .bdrv_create = vpc_create,
};
projects / qemu / blobdiff