2 * Block driver for the various disk image formats used by Bochs
3 * Currently only for "growing" type in read-only mode
5 * Copyright (c) 2005 Alex Beregszaszi
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25 #include "qemu-common.h"
26 #include "block/block_int.h"
27 #include "qemu/module.h"
29 /**************************************************************/
31 #define HEADER_MAGIC "Bochs Virtual HD Image"
32 #define HEADER_VERSION 0x00020000
33 #define HEADER_V1 0x00010000
34 #define HEADER_SIZE 512
36 #define REDOLOG_TYPE "Redolog"
37 #define GROWING_TYPE "Growing"
39 // not allocated: 0xffffffff
41 // always little-endian
43 char magic[32]; /* "Bochs Virtual HD Image" */
44 char type[16]; /* "Redolog" */
45 char subtype[16]; /* "Undoable" / "Volatile" / "Growing" */
47 uint32_t header; /* size of header */
49 uint32_t catalog; /* num of entries */
50 uint32_t bitmap; /* bitmap size */
51 uint32_t extent; /* extent size */
55 uint32_t reserved; /* for ??? */
56 uint64_t disk; /* disk size */
57 char padding[HEADER_SIZE - 64 - 20 - 12];
58 } QEMU_PACKED redolog;
60 uint64_t disk; /* disk size */
61 char padding[HEADER_SIZE - 64 - 20 - 8];
62 } QEMU_PACKED redolog_v1;
63 char padding[HEADER_SIZE - 64 - 20];
67 typedef struct BDRVBochsState {
69 uint32_t *catalog_bitmap;
79 static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
81 const struct bochs_header *bochs = (const void *)buf;
83 if (buf_size < HEADER_SIZE)
86 if (!strcmp(bochs->magic, HEADER_MAGIC) &&
87 !strcmp(bochs->type, REDOLOG_TYPE) &&
88 !strcmp(bochs->subtype, GROWING_TYPE) &&
89 ((le32_to_cpu(bochs->version) == HEADER_VERSION) ||
90 (le32_to_cpu(bochs->version) == HEADER_V1)))
96 static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
99 BDRVBochsState *s = bs->opaque;
101 struct bochs_header bochs;
104 bs->read_only = 1; // no write support yet
106 ret = bdrv_pread(bs->file, 0, &bochs, sizeof(bochs));
111 if (strcmp(bochs.magic, HEADER_MAGIC) ||
112 strcmp(bochs.type, REDOLOG_TYPE) ||
113 strcmp(bochs.subtype, GROWING_TYPE) ||
114 ((le32_to_cpu(bochs.version) != HEADER_VERSION) &&
115 (le32_to_cpu(bochs.version) != HEADER_V1))) {
119 if (le32_to_cpu(bochs.version) == HEADER_V1) {
120 bs->total_sectors = le64_to_cpu(bochs.extra.redolog_v1.disk) / 512;
122 bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512;
125 s->catalog_size = le32_to_cpu(bochs.catalog);
126 s->catalog_bitmap = g_malloc(s->catalog_size * 4);
128 ret = bdrv_pread(bs->file, le32_to_cpu(bochs.header), s->catalog_bitmap,
129 s->catalog_size * 4);
134 for (i = 0; i < s->catalog_size; i++)
135 le32_to_cpus(&s->catalog_bitmap[i]);
137 s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4);
139 s->bitmap_blocks = 1 + (le32_to_cpu(bochs.bitmap) - 1) / 512;
140 s->extent_blocks = 1 + (le32_to_cpu(bochs.extent) - 1) / 512;
142 s->extent_size = le32_to_cpu(bochs.extent);
144 qemu_co_mutex_init(&s->lock);
148 g_free(s->catalog_bitmap);
152 static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
154 BDRVBochsState *s = bs->opaque;
155 int64_t offset = sector_num * 512;
156 int64_t extent_index, extent_offset, bitmap_offset;
160 extent_index = offset / s->extent_size;
161 extent_offset = (offset % s->extent_size) / 512;
163 if (s->catalog_bitmap[extent_index] == 0xffffffff) {
164 return -1; /* not allocated */
167 bitmap_offset = s->data_offset + (512 * s->catalog_bitmap[extent_index] *
168 (s->extent_blocks + s->bitmap_blocks));
170 /* read in bitmap for current extent */
171 if (bdrv_pread(bs->file, bitmap_offset + (extent_offset / 8),
172 &bitmap_entry, 1) != 1) {
176 if (!((bitmap_entry >> (extent_offset % 8)) & 1)) {
177 return -1; /* not allocated */
180 return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset));
183 static int bochs_read(BlockDriverState *bs, int64_t sector_num,
184 uint8_t *buf, int nb_sectors)
188 while (nb_sectors > 0) {
189 int64_t block_offset = seek_to_sector(bs, sector_num);
190 if (block_offset >= 0) {
191 ret = bdrv_pread(bs->file, block_offset, buf, 512);
204 static coroutine_fn int bochs_co_read(BlockDriverState *bs, int64_t sector_num,
205 uint8_t *buf, int nb_sectors)
208 BDRVBochsState *s = bs->opaque;
209 qemu_co_mutex_lock(&s->lock);
210 ret = bochs_read(bs, sector_num, buf, nb_sectors);
211 qemu_co_mutex_unlock(&s->lock);
215 static void bochs_close(BlockDriverState *bs)
217 BDRVBochsState *s = bs->opaque;
218 g_free(s->catalog_bitmap);
221 static BlockDriver bdrv_bochs = {
222 .format_name = "bochs",
223 .instance_size = sizeof(BDRVBochsState),
224 .bdrv_probe = bochs_probe,
225 .bdrv_open = bochs_open,
226 .bdrv_read = bochs_co_read,
227 .bdrv_close = bochs_close,
230 static void bdrv_bochs_init(void)
232 bdrv_register(&bdrv_bochs);
235 block_init(bdrv_bochs_init);