+++ /dev/null
-/*
- * Block driver for Conectix/Microsoft Virtual PC images
- *
- * Copyright (c) 2005 Alex Beregszaszi
- * Copyright (c) 2009 Kevin Wolf <kwolf@suse.de>
- *
- * 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 "qemu-common.h"
-#include "block_int.h"
-
-/**************************************************************/
-
-#define HEADER_SIZE 512
-
-//#define CACHE
-
-enum vhd_type {
- VHD_FIXED = 2,
- VHD_DYNAMIC = 3,
- 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"
- 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"
-
- // 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 {
- BlockDriverState *hd;
-
- uint8_t footer_buf[HEADER_SIZE];
- uint64_t free_data_block_offset;
- int max_table_entries;
- uint32_t *pagetable;
- uint64_t bat_offset;
- uint64_t last_bitmap_offset;
-
- uint32_t block_size;
- uint32_t bitmap_size;
-
-#ifdef CACHE
- uint8_t *pageentry_u8;
- uint32_t *pageentry_u32;
- uint16_t *pageentry_u16;
-
- uint64_t last_bitmap;
-#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))
- return 100;
- return 0;
-}
-
-static int vpc_open(BlockDriverState *bs, const char *filename, int flags)
-{
- BDRVVPCState *s = bs->opaque;
- int ret, i;
- 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)
- return ret;
-
- if (bdrv_pread(s->hd, 0, s->footer_buf, HEADER_SIZE) != HEADER_SIZE)
- goto fail;
-
- footer = (struct vhd_footer*) s->footer_buf;
- 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)
- bs->total_sectors = (int64_t)
- be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl;
-
- if (bdrv_pread(s->hd, be64_to_cpu(footer->data_offset), buf, HEADER_SIZE)
- != HEADER_SIZE)
- goto fail;
-
- dyndisk_header = (struct vhd_dyndisk_header*) buf;
-
- if (strncmp(dyndisk_header->magic, "cxsparse", 8))
- goto fail;
-
-
- s->block_size = be32_to_cpu(dyndisk_header->block_size);
- s->bitmap_size = ((s->block_size / (8 * 512)) + 511) & ~511;
-
- s->max_table_entries = be32_to_cpu(dyndisk_header->max_table_entries);
- s->pagetable = qemu_malloc(s->max_table_entries * 4);
-
- s->bat_offset = be64_to_cpu(dyndisk_header->table_offset);
- if (bdrv_pread(s->hd, s->bat_offset, s->pagetable,
- s->max_table_entries * 4) != s->max_table_entries * 4)
- goto fail;
-
- s->free_data_block_offset =
- (s->bat_offset + (s->max_table_entries * 4) + 511) & ~511;
-
- for (i = 0; i < s->max_table_entries; i++) {
- be32_to_cpus(&s->pagetable[i]);
- if (s->pagetable[i] != 0xFFFFFFFF) {
- int64_t next = (512 * (int64_t) s->pagetable[i]) +
- s->bitmap_size + s->block_size;
-
- if (next> s->free_data_block_offset)
- s->free_data_block_offset = next;
- }
- }
-
- s->last_bitmap_offset = (int64_t) -1;
-
-#ifdef CACHE
- s->pageentry_u8 = qemu_malloc(512);
- s->pageentry_u32 = s->pageentry_u8;
- s->pageentry_u16 = s->pageentry_u8;
- s->last_pagetable = -1;
-#endif
-
- return 0;
- fail:
- bdrv_delete(s->hd);
- return -1;
-}
-
-/*
- * Returns the absolute byte offset of the given sector in the image file.
- * If the sector is not allocated, -1 is returned instead.
- *
- * The parameter write must be 1 if the offset will be used for a write
- * operation (the block bitmaps is updated then), 0 otherwise.
- */
-static inline int64_t get_sector_offset(BlockDriverState *bs,
- int64_t sector_num, int write)
-{
- BDRVVPCState *s = bs->opaque;
- uint64_t offset = sector_num * 512;
- uint64_t bitmap_offset, block_offset;
- uint32_t pagetable_index, pageentry_index;
-
- pagetable_index = offset / s->block_size;
- pageentry_index = (offset % s->block_size) / 512;
-
- if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff)
- return -1; // not allocated
-
- 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
- // unused in the bitmap. We get away with setting all bits in the block
- // bitmap each time we write to a new block. This might cause Virtual PC to
- // miss sparse read optimization, but it's not a problem in terms of
- // correctness.
- if (write && (s->last_bitmap_offset != bitmap_offset)) {
- uint8_t bitmap[s->bitmap_size];
-
- s->last_bitmap_offset = bitmap_offset;
- memset(bitmap, 0xff, s->bitmap_size);
- bdrv_pwrite(s->hd, bitmap_offset, bitmap, s->bitmap_size);
- }
-
-// printf("sector: %" PRIx64 ", index: %x, offset: %x, bioff: %" PRIx64 ", bloff: %" PRIx64 "\n",
-// sector_num, pagetable_index, pageentry_index,
-// bitmap_offset, block_offset);
-
-// disabled by reason
-#if 0
-#ifdef CACHE
- if (bitmap_offset != s->last_bitmap)
- {
- lseek(s->fd, bitmap_offset, SEEK_SET);
-
- s->last_bitmap = bitmap_offset;
-
- // Scary! Bitmap is stored as big endian 32bit entries,
- // while we used to look it up byte by byte
- read(s->fd, s->pageentry_u8, 512);
- for (i = 0; i < 128; i++)
- be32_to_cpus(&s->pageentry_u32[i]);
- }
-
- if ((s->pageentry_u8[pageentry_index / 8] >> (pageentry_index % 8)) & 1)
- return -1;
-#else
- lseek(s->fd, bitmap_offset + (pageentry_index / 8), SEEK_SET);
-
- read(s->fd, &bitmap_entry, 1);
-
- if ((bitmap_entry >> (pageentry_index % 8)) & 1)
- return -1; // not allocated
-#endif
-#endif
-
- return block_offset;
-}
-
-/*
- * Writes the footer to the end of the image file. This is needed when the
- * file grows as it overwrites the old footer
- *
- * Returns 0 on success and < 0 on error
- */
-static int rewrite_footer(BlockDriverState* bs)
-{
- int ret;
- BDRVVPCState *s = bs->opaque;
- int64_t offset = s->free_data_block_offset;
-
- ret = bdrv_pwrite(s->hd, offset, s->footer_buf, HEADER_SIZE);
- if (ret < 0)
- return ret;
-
- return 0;
-}
-
-/*
- * Allocates a new block. This involves writing a new footer and updating
- * the Block Allocation Table to use the space at the old end of the image
- * file (overwriting the old footer)
- *
- * Returns the sectors' offset in the image file on success and < 0 on error
- */
-static int64_t alloc_block(BlockDriverState* bs, int64_t sector_num)
-{
- BDRVVPCState *s = bs->opaque;
- int64_t bat_offset;
- uint32_t index, bat_value;
- int ret;
- uint8_t bitmap[s->bitmap_size];
-
- // Check if sector_num is valid
- if ((sector_num < 0) || (sector_num > bs->total_sectors))
- return -1;
-
- // Write entry into in-memory BAT
- index = (sector_num * 512) / s->block_size;
- if (s->pagetable[index] != 0xFFFFFFFF)
- return -1;
-
- s->pagetable[index] = s->free_data_block_offset / 512;
-
- // Initialize the block's bitmap
- memset(bitmap, 0xff, s->bitmap_size);
- bdrv_pwrite(s->hd, s->free_data_block_offset, bitmap, s->bitmap_size);
-
- // Write new footer (the old one will be overwritten)
- s->free_data_block_offset += s->block_size + s->bitmap_size;
- ret = rewrite_footer(bs);
- if (ret < 0)
- goto fail;
-
- // Write BAT entry to disk
- bat_offset = s->bat_offset + (4 * index);
- bat_value = be32_to_cpu(s->pagetable[index]);
- ret = bdrv_pwrite(s->hd, bat_offset, &bat_value, 4);
- if (ret < 0)
- goto fail;
-
- return get_sector_offset(bs, sector_num, 0);
-
-fail:
- s->free_data_block_offset -= (s->block_size + s->bitmap_size);
- return -1;
-}
-
-static int vpc_read(BlockDriverState *bs, int64_t sector_num,
- uint8_t *buf, int nb_sectors)
-{
- BDRVVPCState *s = bs->opaque;
- int ret;
- int64_t offset;
-
- while (nb_sectors > 0) {
- offset = get_sector_offset(bs, sector_num, 0);
-
- if (offset == -1) {
- memset(buf, 0, 512);
- } else {
- ret = bdrv_pread(s->hd, offset, buf, 512);
- if (ret != 512)
- return -1;
- }
-
- nb_sectors--;
- sector_num++;
- buf += 512;
- }
- return 0;
-}
-
-static int vpc_write(BlockDriverState *bs, int64_t sector_num,
- const uint8_t *buf, int nb_sectors)
-{
- BDRVVPCState *s = bs->opaque;
- int64_t offset;
- int ret;
-
- while (nb_sectors > 0) {
- offset = get_sector_offset(bs, sector_num, 1);
-
- if (offset == -1) {
- offset = alloc_block(bs, sector_num);
- if (offset < 0)
- return -1;
- }
-
- ret = bdrv_pwrite(s->hd, offset, buf, 512);
- if (ret != 512)
- return -1;
-
- nb_sectors--;
- sector_num++;
- buf += 512;
- }
-
- 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.
- *
- * Returns 0 on success, -EFBIG if the size is larger than 127 GB
- */
-static int 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)
- return -EFBIG;
-
- 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;
-
- return 0;
-}
-
-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
- if (calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl))
- return -EFBIG;
- 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;
- qemu_free(s->pagetable);
-#ifdef CACHE
- qemu_free(s->pageentry_u8);
-#endif
- bdrv_delete(s->hd);
-}
-
-BlockDriver bdrv_vpc = {
- .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