kvm-all: trace: strerror fixup
[qemu/ar7.git] / block / bochs.c
blob8b953bb44c7afabcfb13b7d592ec09818381cadc
1 /*
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
23 * THE SOFTWARE.
25 #include "qemu/osdep.h"
26 #include "qemu-common.h"
27 #include "block/block_int.h"
28 #include "qemu/module.h"
30 /**************************************************************/
32 #define HEADER_MAGIC "Bochs Virtual HD Image"
33 #define HEADER_VERSION 0x00020000
34 #define HEADER_V1 0x00010000
35 #define HEADER_SIZE 512
37 #define REDOLOG_TYPE "Redolog"
38 #define GROWING_TYPE "Growing"
40 // not allocated: 0xffffffff
42 // always little-endian
43 struct bochs_header {
44 char magic[32]; /* "Bochs Virtual HD Image" */
45 char type[16]; /* "Redolog" */
46 char subtype[16]; /* "Undoable" / "Volatile" / "Growing" */
47 uint32_t version;
48 uint32_t header; /* size of header */
50 uint32_t catalog; /* num of entries */
51 uint32_t bitmap; /* bitmap size */
52 uint32_t extent; /* extent size */
54 union {
55 struct {
56 uint32_t reserved; /* for ??? */
57 uint64_t disk; /* disk size */
58 char padding[HEADER_SIZE - 64 - 20 - 12];
59 } QEMU_PACKED redolog;
60 struct {
61 uint64_t disk; /* disk size */
62 char padding[HEADER_SIZE - 64 - 20 - 8];
63 } QEMU_PACKED redolog_v1;
64 char padding[HEADER_SIZE - 64 - 20];
65 } extra;
66 } QEMU_PACKED;
68 typedef struct BDRVBochsState {
69 CoMutex lock;
70 uint32_t *catalog_bitmap;
71 uint32_t catalog_size;
73 uint32_t data_offset;
75 uint32_t bitmap_blocks;
76 uint32_t extent_blocks;
77 uint32_t extent_size;
78 } BDRVBochsState;
80 static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
82 const struct bochs_header *bochs = (const void *)buf;
84 if (buf_size < HEADER_SIZE)
85 return 0;
87 if (!strcmp(bochs->magic, HEADER_MAGIC) &&
88 !strcmp(bochs->type, REDOLOG_TYPE) &&
89 !strcmp(bochs->subtype, GROWING_TYPE) &&
90 ((le32_to_cpu(bochs->version) == HEADER_VERSION) ||
91 (le32_to_cpu(bochs->version) == HEADER_V1)))
92 return 100;
94 return 0;
97 static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
98 Error **errp)
100 BDRVBochsState *s = bs->opaque;
101 uint32_t i;
102 struct bochs_header bochs;
103 int ret;
105 bs->read_only = 1; // no write support yet
107 ret = bdrv_pread(bs->file->bs, 0, &bochs, sizeof(bochs));
108 if (ret < 0) {
109 return ret;
112 if (strcmp(bochs.magic, HEADER_MAGIC) ||
113 strcmp(bochs.type, REDOLOG_TYPE) ||
114 strcmp(bochs.subtype, GROWING_TYPE) ||
115 ((le32_to_cpu(bochs.version) != HEADER_VERSION) &&
116 (le32_to_cpu(bochs.version) != HEADER_V1))) {
117 error_setg(errp, "Image not in Bochs format");
118 return -EINVAL;
121 if (le32_to_cpu(bochs.version) == HEADER_V1) {
122 bs->total_sectors = le64_to_cpu(bochs.extra.redolog_v1.disk) / 512;
123 } else {
124 bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512;
127 /* Limit to 1M entries to avoid unbounded allocation. This is what is
128 * needed for the largest image that bximage can create (~8 TB). */
129 s->catalog_size = le32_to_cpu(bochs.catalog);
130 if (s->catalog_size > 0x100000) {
131 error_setg(errp, "Catalog size is too large");
132 return -EFBIG;
135 s->catalog_bitmap = g_try_new(uint32_t, s->catalog_size);
136 if (s->catalog_size && s->catalog_bitmap == NULL) {
137 error_setg(errp, "Could not allocate memory for catalog");
138 return -ENOMEM;
141 ret = bdrv_pread(bs->file->bs, le32_to_cpu(bochs.header), s->catalog_bitmap,
142 s->catalog_size * 4);
143 if (ret < 0) {
144 goto fail;
147 for (i = 0; i < s->catalog_size; i++)
148 le32_to_cpus(&s->catalog_bitmap[i]);
150 s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4);
152 s->bitmap_blocks = 1 + (le32_to_cpu(bochs.bitmap) - 1) / 512;
153 s->extent_blocks = 1 + (le32_to_cpu(bochs.extent) - 1) / 512;
155 s->extent_size = le32_to_cpu(bochs.extent);
156 if (s->extent_size < BDRV_SECTOR_SIZE) {
157 /* bximage actually never creates extents smaller than 4k */
158 error_setg(errp, "Extent size must be at least 512");
159 ret = -EINVAL;
160 goto fail;
161 } else if (!is_power_of_2(s->extent_size)) {
162 error_setg(errp, "Extent size %" PRIu32 " is not a power of two",
163 s->extent_size);
164 ret = -EINVAL;
165 goto fail;
166 } else if (s->extent_size > 0x800000) {
167 error_setg(errp, "Extent size %" PRIu32 " is too large",
168 s->extent_size);
169 ret = -EINVAL;
170 goto fail;
173 if (s->catalog_size < DIV_ROUND_UP(bs->total_sectors,
174 s->extent_size / BDRV_SECTOR_SIZE))
176 error_setg(errp, "Catalog size is too small for this disk size");
177 ret = -EINVAL;
178 goto fail;
181 qemu_co_mutex_init(&s->lock);
182 return 0;
184 fail:
185 g_free(s->catalog_bitmap);
186 return ret;
189 static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
191 BDRVBochsState *s = bs->opaque;
192 uint64_t offset = sector_num * 512;
193 uint64_t extent_index, extent_offset, bitmap_offset;
194 char bitmap_entry;
195 int ret;
197 // seek to sector
198 extent_index = offset / s->extent_size;
199 extent_offset = (offset % s->extent_size) / 512;
201 if (s->catalog_bitmap[extent_index] == 0xffffffff) {
202 return 0; /* not allocated */
205 bitmap_offset = s->data_offset +
206 (512 * (uint64_t) s->catalog_bitmap[extent_index] *
207 (s->extent_blocks + s->bitmap_blocks));
209 /* read in bitmap for current extent */
210 ret = bdrv_pread(bs->file->bs, bitmap_offset + (extent_offset / 8),
211 &bitmap_entry, 1);
212 if (ret < 0) {
213 return ret;
216 if (!((bitmap_entry >> (extent_offset % 8)) & 1)) {
217 return 0; /* not allocated */
220 return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset));
223 static int bochs_read(BlockDriverState *bs, int64_t sector_num,
224 uint8_t *buf, int nb_sectors)
226 int ret;
228 while (nb_sectors > 0) {
229 int64_t block_offset = seek_to_sector(bs, sector_num);
230 if (block_offset < 0) {
231 return block_offset;
232 } else if (block_offset > 0) {
233 ret = bdrv_pread(bs->file->bs, block_offset, buf, 512);
234 if (ret < 0) {
235 return ret;
237 } else {
238 memset(buf, 0, 512);
240 nb_sectors--;
241 sector_num++;
242 buf += 512;
244 return 0;
247 static coroutine_fn int bochs_co_read(BlockDriverState *bs, int64_t sector_num,
248 uint8_t *buf, int nb_sectors)
250 int ret;
251 BDRVBochsState *s = bs->opaque;
252 qemu_co_mutex_lock(&s->lock);
253 ret = bochs_read(bs, sector_num, buf, nb_sectors);
254 qemu_co_mutex_unlock(&s->lock);
255 return ret;
258 static void bochs_close(BlockDriverState *bs)
260 BDRVBochsState *s = bs->opaque;
261 g_free(s->catalog_bitmap);
264 static BlockDriver bdrv_bochs = {
265 .format_name = "bochs",
266 .instance_size = sizeof(BDRVBochsState),
267 .bdrv_probe = bochs_probe,
268 .bdrv_open = bochs_open,
269 .bdrv_read = bochs_co_read,
270 .bdrv_close = bochs_close,
273 static void bdrv_bochs_init(void)
275 bdrv_register(&bdrv_bochs);
278 block_init(bdrv_bochs_init);