/* * Block driver for the various disk image formats used by Bochs * Currently only for "growing" type in read-only mode * * Copyright (c) 2005 Alex Beregszaszi * * 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_MAGIC "Bochs Virtual HD Image" #define HEADER_VERSION 0x00020000 #define HEADER_V1 0x00010000 #define HEADER_SIZE 512 #define REDOLOG_TYPE "Redolog" #define GROWING_TYPE "Growing" // not allocated: 0xffffffff // always little-endian struct bochs_header_v1 { char magic[32]; // "Bochs Virtual HD Image" char type[16]; // "Redolog" char subtype[16]; // "Undoable" / "Volatile" / "Growing" uint32_t version; uint32_t header; // size of header union { struct { uint32_t catalog; // num of entries uint32_t bitmap; // bitmap size uint32_t extent; // extent size uint64_t disk; // disk size char padding[HEADER_SIZE - 64 - 8 - 20]; } redolog; char padding[HEADER_SIZE - 64 - 8]; } extra; }; // always little-endian struct bochs_header { char magic[32]; // "Bochs Virtual HD Image" char type[16]; // "Redolog" char subtype[16]; // "Undoable" / "Volatile" / "Growing" uint32_t version; uint32_t header; // size of header union { struct { uint32_t catalog; // num of entries uint32_t bitmap; // bitmap size uint32_t extent; // extent size uint32_t reserved; // for ??? uint64_t disk; // disk size char padding[HEADER_SIZE - 64 - 8 - 24]; } redolog; char padding[HEADER_SIZE - 64 - 8]; } extra; }; typedef struct BDRVBochsState { uint32_t *catalog_bitmap; int catalog_size; int data_offset; int bitmap_blocks; int extent_blocks; int extent_size; } BDRVBochsState; static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename) { const struct bochs_header *bochs = (const void *)buf; if (buf_size < HEADER_SIZE) return 0; if (!strcmp(bochs->magic, HEADER_MAGIC) && !strcmp(bochs->type, REDOLOG_TYPE) && !strcmp(bochs->subtype, GROWING_TYPE) && ((le32_to_cpu(bochs->version) == HEADER_VERSION) || (le32_to_cpu(bochs->version) == HEADER_V1))) return 100; return 0; } static int bochs_open(BlockDriverState *bs, int flags) { BDRVBochsState *s = bs->opaque; int i; struct bochs_header bochs; struct bochs_header_v1 header_v1; bs->read_only = 1; // no write support yet if (bdrv_pread(bs->file, 0, &bochs, sizeof(bochs)) != sizeof(bochs)) { goto fail; } if (strcmp(bochs.magic, HEADER_MAGIC) || strcmp(bochs.type, REDOLOG_TYPE) || strcmp(bochs.subtype, GROWING_TYPE) || ((le32_to_cpu(bochs.version) != HEADER_VERSION) && (le32_to_cpu(bochs.version) != HEADER_V1))) { goto fail; } if (le32_to_cpu(bochs.version) == HEADER_V1) { memcpy(&header_v1, &bochs, sizeof(bochs)); bs->total_sectors = le64_to_cpu(header_v1.extra.redolog.disk) / 512; } else { bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512; } s->catalog_size = le32_to_cpu(bochs.extra.redolog.catalog); s->catalog_bitmap = qemu_malloc(s->catalog_size * 4); if (bdrv_pread(bs->file, le32_to_cpu(bochs.header), s->catalog_bitmap, s->catalog_size * 4) != s->catalog_size * 4) goto fail; for (i = 0; i < s->catalog_size; i++) le32_to_cpus(&s->catalog_bitmap[i]); s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4); s->bitmap_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.bitmap) - 1) / 512; s->extent_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.extent) - 1) / 512; s->extent_size = le32_to_cpu(bochs.extra.redolog.extent); return 0; fail: return -1; } static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num) { BDRVBochsState *s = bs->opaque; int64_t offset = sector_num * 512; int64_t extent_index, extent_offset, bitmap_offset; char bitmap_entry; // seek to sector extent_index = offset / s->extent_size; extent_offset = (offset % s->extent_size) / 512; if (s->catalog_bitmap[extent_index] == 0xffffffff) { return -1; /* not allocated */ } bitmap_offset = s->data_offset + (512 * s->catalog_bitmap[extent_index] * (s->extent_blocks + s->bitmap_blocks)); /* read in bitmap for current extent */ if (bdrv_pread(bs->file, bitmap_offset + (extent_offset / 8), &bitmap_entry, 1) != 1) { return -1; } if (!((bitmap_entry >> (extent_offset % 8)) & 1)) { return -1; /* not allocated */ } return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset)); } static int bochs_read(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, int nb_sectors) { int ret; while (nb_sectors > 0) { int64_t block_offset = seek_to_sector(bs, sector_num); if (block_offset >= 0) { ret = bdrv_pread(bs->file, block_offset, buf, 512); if (ret != 512) { return -1; } } else memset(buf, 0, 512); nb_sectors--; sector_num++; buf += 512; } return 0; } static void bochs_close(BlockDriverState *bs) { BDRVBochsState *s = bs->opaque; qemu_free(s->catalog_bitmap); } static BlockDriver bdrv_bochs = { .format_name = "bochs", .instance_size = sizeof(BDRVBochsState), .bdrv_probe = bochs_probe, .bdrv_open = bochs_open, .bdrv_read = bochs_read, .bdrv_close = bochs_close, }; static void bdrv_bochs_init(void) { bdrv_register(&bdrv_bochs); } block_init(bdrv_bochs_init);