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1.1 root 1: /*
2: * Block driver for the various disk image formats used by Bochs
3: * Currently only for "growing" type in read-only mode
4: *
5: * Copyright (c) 2005 Alex Beregszaszi
6: *
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:
13: *
14: * The above copyright notice and this permission notice shall be included in
15: * all copies or substantial portions of the Software.
16: *
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
23: * THE SOFTWARE.
24: */
25: #include "qemu-common.h"
26: #include "block_int.h"
27: #include "module.h"
28:
29: /**************************************************************/
30:
31: #define HEADER_MAGIC "Bochs Virtual HD Image"
32: #define HEADER_VERSION 0x00020000
33: #define HEADER_V1 0x00010000
34: #define HEADER_SIZE 512
35:
36: #define REDOLOG_TYPE "Redolog"
37: #define GROWING_TYPE "Growing"
38:
39: // not allocated: 0xffffffff
40:
41: // always little-endian
42: struct bochs_header_v1 {
43: char magic[32]; // "Bochs Virtual HD Image"
44: char type[16]; // "Redolog"
45: char subtype[16]; // "Undoable" / "Volatile" / "Growing"
46: uint32_t version;
47: uint32_t header; // size of header
48:
49: union {
50: struct {
51: uint32_t catalog; // num of entries
52: uint32_t bitmap; // bitmap size
53: uint32_t extent; // extent size
54: uint64_t disk; // disk size
55: char padding[HEADER_SIZE - 64 - 8 - 20];
56: } redolog;
57: char padding[HEADER_SIZE - 64 - 8];
58: } extra;
59: };
60:
61: // always little-endian
62: struct bochs_header {
63: char magic[32]; // "Bochs Virtual HD Image"
64: char type[16]; // "Redolog"
65: char subtype[16]; // "Undoable" / "Volatile" / "Growing"
66: uint32_t version;
67: uint32_t header; // size of header
68:
69: union {
70: struct {
71: uint32_t catalog; // num of entries
72: uint32_t bitmap; // bitmap size
73: uint32_t extent; // extent size
74: uint32_t reserved; // for ???
75: uint64_t disk; // disk size
76: char padding[HEADER_SIZE - 64 - 8 - 24];
77: } redolog;
78: char padding[HEADER_SIZE - 64 - 8];
79: } extra;
80: };
81:
82: typedef struct BDRVBochsState {
83: uint32_t *catalog_bitmap;
84: int catalog_size;
85:
86: int data_offset;
87:
88: int bitmap_blocks;
89: int extent_blocks;
90: int extent_size;
91: } BDRVBochsState;
92:
93: static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
94: {
95: const struct bochs_header *bochs = (const void *)buf;
96:
97: if (buf_size < HEADER_SIZE)
98: return 0;
99:
100: if (!strcmp(bochs->magic, HEADER_MAGIC) &&
101: !strcmp(bochs->type, REDOLOG_TYPE) &&
102: !strcmp(bochs->subtype, GROWING_TYPE) &&
103: ((le32_to_cpu(bochs->version) == HEADER_VERSION) ||
104: (le32_to_cpu(bochs->version) == HEADER_V1)))
105: return 100;
106:
107: return 0;
108: }
109:
1.1.1.2 ! root 110: static int bochs_open(BlockDriverState *bs, int flags)
1.1 root 111: {
112: BDRVBochsState *s = bs->opaque;
1.1.1.2 ! root 113: int i;
1.1 root 114: struct bochs_header bochs;
115: struct bochs_header_v1 header_v1;
116:
117: bs->read_only = 1; // no write support yet
118:
1.1.1.2 ! root 119: if (bdrv_pread(bs->file, 0, &bochs, sizeof(bochs)) != sizeof(bochs)) {
1.1 root 120: goto fail;
121: }
122:
123: if (strcmp(bochs.magic, HEADER_MAGIC) ||
124: strcmp(bochs.type, REDOLOG_TYPE) ||
125: strcmp(bochs.subtype, GROWING_TYPE) ||
126: ((le32_to_cpu(bochs.version) != HEADER_VERSION) &&
127: (le32_to_cpu(bochs.version) != HEADER_V1))) {
128: goto fail;
129: }
130:
131: if (le32_to_cpu(bochs.version) == HEADER_V1) {
132: memcpy(&header_v1, &bochs, sizeof(bochs));
133: bs->total_sectors = le64_to_cpu(header_v1.extra.redolog.disk) / 512;
134: } else {
135: bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512;
136: }
137:
138: s->catalog_size = le32_to_cpu(bochs.extra.redolog.catalog);
139: s->catalog_bitmap = qemu_malloc(s->catalog_size * 4);
1.1.1.2 ! root 140: if (bdrv_pread(bs->file, le32_to_cpu(bochs.header), s->catalog_bitmap,
! 141: s->catalog_size * 4) != s->catalog_size * 4)
1.1 root 142: goto fail;
143: for (i = 0; i < s->catalog_size; i++)
144: le32_to_cpus(&s->catalog_bitmap[i]);
145:
146: s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4);
147:
148: s->bitmap_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.bitmap) - 1) / 512;
149: s->extent_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.extent) - 1) / 512;
150:
151: s->extent_size = le32_to_cpu(bochs.extra.redolog.extent);
152:
153: return 0;
154: fail:
155: return -1;
156: }
157:
1.1.1.2 ! root 158: static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
1.1 root 159: {
160: BDRVBochsState *s = bs->opaque;
161: int64_t offset = sector_num * 512;
1.1.1.2 ! root 162: int64_t extent_index, extent_offset, bitmap_offset;
1.1 root 163: char bitmap_entry;
164:
165: // seek to sector
166: extent_index = offset / s->extent_size;
167: extent_offset = (offset % s->extent_size) / 512;
168:
1.1.1.2 ! root 169: if (s->catalog_bitmap[extent_index] == 0xffffffff) {
! 170: return -1; /* not allocated */
1.1 root 171: }
172:
173: bitmap_offset = s->data_offset + (512 * s->catalog_bitmap[extent_index] *
174: (s->extent_blocks + s->bitmap_blocks));
175:
1.1.1.2 ! root 176: /* read in bitmap for current extent */
! 177: if (bdrv_pread(bs->file, bitmap_offset + (extent_offset / 8),
! 178: &bitmap_entry, 1) != 1) {
! 179: return -1;
1.1 root 180: }
181:
1.1.1.2 ! root 182: if (!((bitmap_entry >> (extent_offset % 8)) & 1)) {
! 183: return -1; /* not allocated */
! 184: }
1.1 root 185:
1.1.1.2 ! root 186: return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset));
1.1 root 187: }
188:
189: static int bochs_read(BlockDriverState *bs, int64_t sector_num,
190: uint8_t *buf, int nb_sectors)
191: {
192: int ret;
193:
194: while (nb_sectors > 0) {
1.1.1.2 ! root 195: int64_t block_offset = seek_to_sector(bs, sector_num);
! 196: if (block_offset >= 0) {
! 197: ret = bdrv_pread(bs->file, block_offset, buf, 512);
! 198: if (ret != 512) {
! 199: return -1;
! 200: }
! 201: } else
1.1 root 202: memset(buf, 0, 512);
203: nb_sectors--;
204: sector_num++;
205: buf += 512;
206: }
207: return 0;
208: }
209:
210: static void bochs_close(BlockDriverState *bs)
211: {
212: BDRVBochsState *s = bs->opaque;
213: qemu_free(s->catalog_bitmap);
214: }
215:
216: static BlockDriver bdrv_bochs = {
217: .format_name = "bochs",
218: .instance_size = sizeof(BDRVBochsState),
219: .bdrv_probe = bochs_probe,
220: .bdrv_open = bochs_open,
221: .bdrv_read = bochs_read,
222: .bdrv_close = bochs_close,
223: };
224:
225: static void bdrv_bochs_init(void)
226: {
227: bdrv_register(&bdrv_bochs);
228: }
229:
230: block_init(bdrv_bochs_init);
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