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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 {
1.1.1.3 ! root 83: CoMutex lock;
1.1 root 84: uint32_t *catalog_bitmap;
85: int catalog_size;
86:
87: int data_offset;
88:
89: int bitmap_blocks;
90: int extent_blocks;
91: int extent_size;
92: } BDRVBochsState;
93:
94: static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
95: {
96: const struct bochs_header *bochs = (const void *)buf;
97:
98: if (buf_size < HEADER_SIZE)
99: return 0;
100:
101: if (!strcmp(bochs->magic, HEADER_MAGIC) &&
102: !strcmp(bochs->type, REDOLOG_TYPE) &&
103: !strcmp(bochs->subtype, GROWING_TYPE) &&
104: ((le32_to_cpu(bochs->version) == HEADER_VERSION) ||
105: (le32_to_cpu(bochs->version) == HEADER_V1)))
106: return 100;
107:
108: return 0;
109: }
110:
1.1.1.2 root 111: static int bochs_open(BlockDriverState *bs, int flags)
1.1 root 112: {
113: BDRVBochsState *s = bs->opaque;
1.1.1.2 root 114: int i;
1.1 root 115: struct bochs_header bochs;
116: struct bochs_header_v1 header_v1;
117:
118: bs->read_only = 1; // no write support yet
119:
1.1.1.2 root 120: if (bdrv_pread(bs->file, 0, &bochs, sizeof(bochs)) != sizeof(bochs)) {
1.1 root 121: goto fail;
122: }
123:
124: if (strcmp(bochs.magic, HEADER_MAGIC) ||
125: strcmp(bochs.type, REDOLOG_TYPE) ||
126: strcmp(bochs.subtype, GROWING_TYPE) ||
127: ((le32_to_cpu(bochs.version) != HEADER_VERSION) &&
128: (le32_to_cpu(bochs.version) != HEADER_V1))) {
129: goto fail;
130: }
131:
132: if (le32_to_cpu(bochs.version) == HEADER_V1) {
133: memcpy(&header_v1, &bochs, sizeof(bochs));
134: bs->total_sectors = le64_to_cpu(header_v1.extra.redolog.disk) / 512;
135: } else {
136: bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512;
137: }
138:
139: s->catalog_size = le32_to_cpu(bochs.extra.redolog.catalog);
1.1.1.3 ! root 140: s->catalog_bitmap = g_malloc(s->catalog_size * 4);
1.1.1.2 root 141: if (bdrv_pread(bs->file, le32_to_cpu(bochs.header), s->catalog_bitmap,
142: s->catalog_size * 4) != s->catalog_size * 4)
1.1 root 143: goto fail;
144: for (i = 0; i < s->catalog_size; i++)
145: le32_to_cpus(&s->catalog_bitmap[i]);
146:
147: s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4);
148:
149: s->bitmap_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.bitmap) - 1) / 512;
150: s->extent_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.extent) - 1) / 512;
151:
152: s->extent_size = le32_to_cpu(bochs.extra.redolog.extent);
153:
1.1.1.3 ! root 154: qemu_co_mutex_init(&s->lock);
1.1 root 155: return 0;
156: fail:
157: return -1;
158: }
159:
1.1.1.2 root 160: static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
1.1 root 161: {
162: BDRVBochsState *s = bs->opaque;
163: int64_t offset = sector_num * 512;
1.1.1.2 root 164: int64_t extent_index, extent_offset, bitmap_offset;
1.1 root 165: char bitmap_entry;
166:
167: // seek to sector
168: extent_index = offset / s->extent_size;
169: extent_offset = (offset % s->extent_size) / 512;
170:
1.1.1.2 root 171: if (s->catalog_bitmap[extent_index] == 0xffffffff) {
172: return -1; /* not allocated */
1.1 root 173: }
174:
175: bitmap_offset = s->data_offset + (512 * s->catalog_bitmap[extent_index] *
176: (s->extent_blocks + s->bitmap_blocks));
177:
1.1.1.2 root 178: /* read in bitmap for current extent */
179: if (bdrv_pread(bs->file, bitmap_offset + (extent_offset / 8),
180: &bitmap_entry, 1) != 1) {
181: return -1;
1.1 root 182: }
183:
1.1.1.2 root 184: if (!((bitmap_entry >> (extent_offset % 8)) & 1)) {
185: return -1; /* not allocated */
186: }
1.1 root 187:
1.1.1.2 root 188: return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset));
1.1 root 189: }
190:
191: static int bochs_read(BlockDriverState *bs, int64_t sector_num,
192: uint8_t *buf, int nb_sectors)
193: {
194: int ret;
195:
196: while (nb_sectors > 0) {
1.1.1.2 root 197: int64_t block_offset = seek_to_sector(bs, sector_num);
198: if (block_offset >= 0) {
199: ret = bdrv_pread(bs->file, block_offset, buf, 512);
200: if (ret != 512) {
201: return -1;
202: }
203: } else
1.1 root 204: memset(buf, 0, 512);
205: nb_sectors--;
206: sector_num++;
207: buf += 512;
208: }
209: return 0;
210: }
211:
1.1.1.3 ! root 212: static coroutine_fn int bochs_co_read(BlockDriverState *bs, int64_t sector_num,
! 213: uint8_t *buf, int nb_sectors)
! 214: {
! 215: int ret;
! 216: BDRVBochsState *s = bs->opaque;
! 217: qemu_co_mutex_lock(&s->lock);
! 218: ret = bochs_read(bs, sector_num, buf, nb_sectors);
! 219: qemu_co_mutex_unlock(&s->lock);
! 220: return ret;
! 221: }
! 222:
1.1 root 223: static void bochs_close(BlockDriverState *bs)
224: {
225: BDRVBochsState *s = bs->opaque;
1.1.1.3 ! root 226: g_free(s->catalog_bitmap);
1.1 root 227: }
228:
229: static BlockDriver bdrv_bochs = {
230: .format_name = "bochs",
231: .instance_size = sizeof(BDRVBochsState),
232: .bdrv_probe = bochs_probe,
233: .bdrv_open = bochs_open,
1.1.1.3 ! root 234: .bdrv_read = bochs_co_read,
1.1 root 235: .bdrv_close = bochs_close,
236: };
237:
238: static void bdrv_bochs_init(void)
239: {
240: bdrv_register(&bdrv_bochs);
241: }
242:
243: block_init(bdrv_bochs_init);
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