root / block / bochs.c @ 1a1ea6f0
History | View | Annotate | Download (6.6 kB)
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 |
|
110 |
static int bochs_open(BlockDriverState *bs, int flags) |
111 |
{ |
112 |
BDRVBochsState *s = bs->opaque; |
113 |
int i;
|
114 |
struct bochs_header bochs;
|
115 |
struct bochs_header_v1 header_v1;
|
116 |
|
117 |
bs->read_only = 1; // no write support yet |
118 |
|
119 |
if (bdrv_pread(bs->file, 0, &bochs, sizeof(bochs)) != sizeof(bochs)) { |
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);
|
140 |
if (bdrv_pread(bs->file, le32_to_cpu(bochs.header), s->catalog_bitmap,
|
141 |
s->catalog_size * 4) != s->catalog_size * 4) |
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 |
|
158 |
static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
|
159 |
{ |
160 |
BDRVBochsState *s = bs->opaque; |
161 |
int64_t offset = sector_num * 512;
|
162 |
int64_t extent_index, extent_offset, bitmap_offset; |
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 |
|
169 |
if (s->catalog_bitmap[extent_index] == 0xffffffff) { |
170 |
return -1; /* not allocated */ |
171 |
} |
172 |
|
173 |
bitmap_offset = s->data_offset + (512 * s->catalog_bitmap[extent_index] *
|
174 |
(s->extent_blocks + s->bitmap_blocks)); |
175 |
|
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; |
180 |
} |
181 |
|
182 |
if (!((bitmap_entry >> (extent_offset % 8)) & 1)) { |
183 |
return -1; /* not allocated */ |
184 |
} |
185 |
|
186 |
return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset)); |
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) { |
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
|
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); |