diff options
Diffstat (limited to 'block-bochs.c')
| -rw-r--r-- | block-bochs.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/block-bochs.c b/block-bochs.c new file mode 100644 index 0000000000..62317aff38 --- /dev/null +++ b/block-bochs.c @@ -0,0 +1,224 @@ +/* + * 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 "vl.h" +#include "block_int.h" + +/**************************************************************/ + +#define HEADER_MAGIC "Bochs Virtual HD Image" +#define HEADER_VERSION 0x00010000 +#define HEADER_SIZE 512 + +#define REDOLOG_TYPE "Redolog" +#define GROWING_TYPE "Growing" + +// not allocated: 0xffffffff + +// 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 + uint64_t disk; // disk size + char padding[HEADER_SIZE - 64 - 8 - 20]; + } redolog; + char padding[HEADER_SIZE - 64 - 8]; + } extra; +}; + +typedef struct BDRVBochsState { + int fd; + + 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)) + return 100; + + return 0; +} + +static int bochs_open(BlockDriverState *bs, const char *filename) +{ + BDRVBochsState *s = bs->opaque; + int fd, i; + struct bochs_header bochs; + + 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; + + if (read(fd, &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)) { + goto fail; + } + + bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512; + + lseek(s->fd, le32_to_cpu(bochs.header), SEEK_SET); + + s->catalog_size = le32_to_cpu(bochs.extra.redolog.catalog); + s->catalog_bitmap = qemu_malloc(s->catalog_size * 4); + if (!s->catalog_bitmap) + goto fail; + if (read(s->fd, 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: + close(fd); + return -1; +} + +static inline int 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, block_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) + { +// fprintf(stderr, "page not allocated [%x - %x:%x]\n", +// sector_num, extent_index, extent_offset); + return -1; // not allocated + } + + bitmap_offset = s->data_offset + (512 * s->catalog_bitmap[extent_index] * + (s->extent_blocks + s->bitmap_blocks)); + block_offset = bitmap_offset + (512 * (s->bitmap_blocks + extent_offset)); + +// fprintf(stderr, "sect: %x [ext i: %x o: %x] -> %x bitmap: %x block: %x\n", +// sector_num, extent_index, extent_offset, +// le32_to_cpu(s->catalog_bitmap[extent_index]), +// bitmap_offset, block_offset); + + // read in bitmap for current extent + lseek(s->fd, bitmap_offset + (extent_offset / 8), SEEK_SET); + + read(s->fd, &bitmap_entry, 1); + + if (!((bitmap_entry >> (extent_offset % 8)) & 1)) + { +// fprintf(stderr, "sector (%x) in bitmap not allocated\n", +// sector_num); + return -1; // not allocated + } + + lseek(s->fd, block_offset, SEEK_SET); + + return 0; +} + +static int bochs_read(BlockDriverState *bs, int64_t sector_num, + uint8_t *buf, int nb_sectors) +{ + BDRVBochsState *s = bs->opaque; + int ret; + + while (nb_sectors > 0) { + if (!seek_to_sector(bs, sector_num)) + { + ret = read(s->fd, 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); + close(s->fd); +} + +BlockDriver bdrv_bochs = { + "bochs", + sizeof(BDRVBochsState), + bochs_probe, + bochs_open, + bochs_read, + NULL, + bochs_close, +}; 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