X-Git-Url: http://git.maemo.org/git/?a=blobdiff_plain;f=block-vpc.c;h=7ae520235f8a23f18e33218d309a626209a67fbd;hb=aa4b81806d986e649c35700d552e7ba541c01477;hp=bdc3b8891c38c05442e7c6981cc74a68767a7a56;hpb=26a76461f259031f2c30cd5843a5ca91e056cf03;p=qemu diff --git a/block-vpc.c b/block-vpc.c index bdc3b88..7ae5202 100644 --- a/block-vpc.c +++ b/block-vpc.c @@ -1,8 +1,9 @@ /* * Block driver for Conectix/Microsoft Virtual PC images - * + * * Copyright (c) 2005 Alex Beregszaszi - * + * Copyright (c) 2009 Kevin Wolf + * * 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 @@ -21,7 +22,7 @@ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ -#include "vl.h" +#include "qemu-common.h" #include "block_int.h" /**************************************************************/ @@ -30,112 +31,195 @@ //#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 vpc_subheader { - char magic[8]; // "conectix" / "cxsparse" - union { - struct { - uint32_t unk1[2]; - uint32_t unk2; // always zero? - uint32_t subheader_offset; - uint32_t unk3; // some size? - char creator[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 padding[HEADER_SIZE - 84]; - } main; - struct { - 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 padding[HEADER_SIZE - 40]; - } sparse; - char padding[HEADER_SIZE - 8]; - } type; +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 { - int fd; - - int pagetable_entries; + 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; - uint32_t pageentry_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(buf, "conectix", 8)) + if (buf_size >= 8 && !strncmp((char *)buf, "conectix", 8)) return 100; return 0; } -static int vpc_open(BlockDriverState *bs, const char *filename) +static int vpc_open(BlockDriverState *bs, const char *filename, int flags) { BDRVVPCState *s = bs->opaque; - int fd, i; - struct vpc_subheader header; + int ret, i; + struct vhd_footer* footer; + struct vhd_dyndisk_header* dyndisk_header; + uint8_t buf[HEADER_SIZE]; + uint32_t checksum; - fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE); - if (fd < 0) { - fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE); - if (fd < 0) - return -1; - } - - bs->read_only = 1; // no write support yet - - s->fd = fd; + ret = bdrv_file_open(&s->hd, filename, flags); + if (ret < 0) + return ret; - if (read(fd, &header, HEADER_SIZE) != HEADER_SIZE) + if (bdrv_pread(s->hd, 0, s->footer_buf, HEADER_SIZE) != HEADER_SIZE) goto fail; - if (strncmp(header.magic, "conectix", 8)) + footer = (struct vhd_footer*) s->footer_buf; + if (strncmp(footer->creator, "conectix", 8)) goto fail; - lseek(s->fd, be32_to_cpu(header.type.main.subheader_offset), SEEK_SET); - if (read(fd, &header, HEADER_SIZE) != HEADER_SIZE) + 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; - if (strncmp(header.magic, "cxsparse", 8)) - goto fail; + dyndisk_header = (struct vhd_dyndisk_header*) buf; - bs->total_sectors = ((uint64_t)be32_to_cpu(header.type.sparse.pagetable_entries) * - be32_to_cpu(header.type.sparse.pageentry_size)) / 512; + if (strncmp(dyndisk_header->magic, "cxsparse", 8)) + goto fail; - lseek(s->fd, be32_to_cpu(header.type.sparse.pagetable_offset), SEEK_SET); - s->pagetable_entries = be32_to_cpu(header.type.sparse.pagetable_entries); - s->pagetable = qemu_malloc(s->pagetable_entries * 4); - if (!s->pagetable) - goto fail; - if (read(s->fd, s->pagetable, s->pagetable_entries * 4) != - s->pagetable_entries * 4) - goto fail; - for (i = 0; i < s->pagetable_entries; i++) - be32_to_cpus(&s->pagetable[i]); + 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; - s->pageentry_size = be32_to_cpu(header.type.sparse.pageentry_size); #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; @@ -143,26 +227,47 @@ static int vpc_open(BlockDriverState *bs, const char *filename) return 0; fail: - close(fd); + bdrv_delete(s->hd); return -1; } -static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num) +/* + * 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->pageentry_size; - pageentry_index = (offset % s->pageentry_size) / 512; - - if (pagetable_index > s->pagetable_entries || s->pagetable[pagetable_index] == 0xffffffff) - return -1; // not allocated + 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); + } - bitmap_offset = 512 * s->pagetable[pagetable_index]; - block_offset = bitmap_offset + 512 + (512 * pageentry_index); - // printf("sector: %" PRIx64 ", index: %x, offset: %x, bioff: %" PRIx64 ", bloff: %" PRIx64 "\n", // sector_num, pagetable_index, pageentry_index, // bitmap_offset, block_offset); @@ -175,7 +280,7 @@ static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num) 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); @@ -187,33 +292,104 @@ static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num) 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 - lseek(s->fd, block_offset, SEEK_SET); + + 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; } -static int vpc_read(BlockDriverState *bs, int64_t sector_num, +/* + * 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) { - if (!seek_to_sector(bs, sector_num)) - { - ret = read(s->fd, buf, 512); - if (ret != 512) - return -1; - } - else + 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; @@ -221,6 +397,180 @@ static int vpc_read(BlockDriverState *bs, int64_t sector_num, 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. + */ +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; @@ -228,15 +578,16 @@ static void vpc_close(BlockDriverState *bs) #ifdef CACHE qemu_free(s->pageentry_u8); #endif - close(s->fd); + bdrv_delete(s->hd); } BlockDriver bdrv_vpc = { - "vpc", - sizeof(BDRVVPCState), - vpc_probe, - vpc_open, - vpc_read, - NULL, - 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, };