| /* |
| * Block driver for Connectix / 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" |
| #include "module.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 { |
| 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, int flags) |
| { |
| BDRVVPCState *s = bs->opaque; |
| int i; |
| struct vhd_footer* footer; |
| struct vhd_dyndisk_header* dyndisk_header; |
| uint8_t buf[HEADER_SIZE]; |
| uint32_t checksum; |
| int err = -1; |
| |
| if (bdrv_pread(bs->file, 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", bs->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 (bs->total_sectors >= 65535 * 16 * 255) { |
| err = -EFBIG; |
| goto fail; |
| } |
| |
| if (bdrv_pread(bs->file, 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 = g_malloc(s->max_table_entries * 4); |
| |
| s->bat_offset = be64_to_cpu(dyndisk_header->table_offset); |
| if (bdrv_pread(bs->file, 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 = g_malloc(512); |
| s->pageentry_u32 = s->pageentry_u8; |
| s->pageentry_u16 = s->pageentry_u8; |
| s->last_pagetable = -1; |
| #endif |
| |
| return 0; |
| fail: |
| return err; |
| } |
| |
| /* |
| * 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_sync(bs->file, 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_sync(bs->file, 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_sync(bs->file, 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_sync(bs->file, 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; |
| int64_t sectors, sectors_per_block; |
| |
| while (nb_sectors > 0) { |
| offset = get_sector_offset(bs, sector_num, 0); |
| |
| sectors_per_block = s->block_size >> BDRV_SECTOR_BITS; |
| sectors = sectors_per_block - (sector_num % sectors_per_block); |
| if (sectors > nb_sectors) { |
| sectors = nb_sectors; |
| } |
| |
| if (offset == -1) { |
| memset(buf, 0, sectors * BDRV_SECTOR_SIZE); |
| } else { |
| ret = bdrv_pread(bs->file, offset, buf, |
| sectors * BDRV_SECTOR_SIZE); |
| if (ret != sectors * BDRV_SECTOR_SIZE) { |
| return -1; |
| } |
| } |
| |
| nb_sectors -= sectors; |
| sector_num += sectors; |
| buf += sectors * BDRV_SECTOR_SIZE; |
| } |
| 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; |
| int64_t sectors, sectors_per_block; |
| int ret; |
| |
| while (nb_sectors > 0) { |
| offset = get_sector_offset(bs, sector_num, 1); |
| |
| sectors_per_block = s->block_size >> BDRV_SECTOR_BITS; |
| sectors = sectors_per_block - (sector_num % sectors_per_block); |
| if (sectors > nb_sectors) { |
| sectors = nb_sectors; |
| } |
| |
| if (offset == -1) { |
| offset = alloc_block(bs, sector_num); |
| if (offset < 0) |
| return -1; |
| } |
| |
| ret = bdrv_pwrite(bs->file, offset, buf, sectors * BDRV_SECTOR_SIZE); |
| if (ret != sectors * BDRV_SECTOR_SIZE) { |
| return -1; |
| } |
| |
| nb_sectors -= sectors; |
| sector_num += sectors; |
| buf += sectors * BDRV_SECTOR_SIZE; |
| } |
| |
| return 0; |
| } |
| |
| static int vpc_flush(BlockDriverState *bs) |
| { |
| return bdrv_flush(bs->file); |
| } |
| |
| /* |
| * 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; |
| } |
| } |
| |
| *cyls = cyls_times_heads / *heads; |
| |
| return 0; |
| } |
| |
| static int vpc_create(const char *filename, QEMUOptionParameter *options) |
| { |
| 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 = 0; |
| uint8_t heads = 0; |
| uint8_t secs_per_cyl = 0; |
| size_t block_size, num_bat_entries; |
| int64_t total_sectors = 0; |
| int ret = -EIO; |
| |
| // Read out options |
| total_sectors = get_option_parameter(options, BLOCK_OPT_SIZE)->value.n / |
| BDRV_SECTOR_SIZE; |
| |
| // Create the file |
| fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644); |
| if (fd < 0) |
| return -EIO; |
| |
| /* Calculate matching total_size and geometry. Increase the number of |
| sectors requested until we get enough (or fail). */ |
| for (i = 0; total_sectors > (int64_t)cyls * heads * secs_per_cyl; i++) { |
| if (calculate_geometry(total_sectors + i, |
| &cyls, &heads, &secs_per_cyl)) { |
| ret = -EFBIG; |
| goto fail; |
| } |
| } |
| total_sectors = (int64_t) cyls * heads * secs_per_cyl; |
| |
| // Prepare the Hard Disk Footer |
| memset(buf, 0, 1024); |
| |
| memcpy(footer->creator, "conectix", 8); |
| // TODO Check if "qemu" creator_app is ok for VPC |
| memcpy(footer->creator_app, "qemu", 4); |
| memcpy(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) { |
| goto fail; |
| } |
| |
| if (lseek(fd, 1536 + ((num_bat_entries * 4 + 511) & ~511), SEEK_SET) < 0) { |
| goto fail; |
| } |
| if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE) { |
| goto fail; |
| } |
| |
| // Write the initial BAT |
| if (lseek(fd, 3 * 512, SEEK_SET) < 0) { |
| goto fail; |
| } |
| |
| memset(buf, 0xFF, 512); |
| for (i = 0; i < (num_bat_entries * 4 + 511) / 512; i++) { |
| if (write(fd, buf, 512) != 512) { |
| goto fail; |
| } |
| } |
| |
| |
| // Prepare the Dynamic Disk Header |
| memset(buf, 0, 1024); |
| |
| memcpy(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) { |
| goto fail; |
| } |
| |
| if (write(fd, buf, 1024) != 1024) { |
| goto fail; |
| } |
| ret = 0; |
| |
| fail: |
| close(fd); |
| return ret; |
| } |
| |
| static void vpc_close(BlockDriverState *bs) |
| { |
| BDRVVPCState *s = bs->opaque; |
| g_free(s->pagetable); |
| #ifdef CACHE |
| g_free(s->pageentry_u8); |
| #endif |
| } |
| |
| static QEMUOptionParameter vpc_create_options[] = { |
| { |
| .name = BLOCK_OPT_SIZE, |
| .type = OPT_SIZE, |
| .help = "Virtual disk size" |
| }, |
| { NULL } |
| }; |
| |
| static 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_flush = vpc_flush, |
| .bdrv_close = vpc_close, |
| .bdrv_create = vpc_create, |
| |
| .create_options = vpc_create_options, |
| }; |
| |
| static void bdrv_vpc_init(void) |
| { |
| bdrv_register(&bdrv_vpc); |
| } |
| |
| block_init(bdrv_vpc_init); |