root / block-qcow.c @ f68c781c
History | View | Annotate | Download (21.9 kB)
1 |
/*
|
---|---|
2 |
* Block driver for the QCOW format
|
3 |
*
|
4 |
* Copyright (c) 2004 Fabrice Bellard
|
5 |
*
|
6 |
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
7 |
* of this software and associated documentation files (the "Software"), to deal
|
8 |
* in the Software without restriction, including without limitation the rights
|
9 |
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
10 |
* copies of the Software, and to permit persons to whom the Software is
|
11 |
* furnished to do so, subject to the following conditions:
|
12 |
*
|
13 |
* The above copyright notice and this permission notice shall be included in
|
14 |
* all copies or substantial portions of the Software.
|
15 |
*
|
16 |
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
17 |
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
18 |
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
|
19 |
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
20 |
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
21 |
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
22 |
* THE SOFTWARE.
|
23 |
*/
|
24 |
#include "vl.h" |
25 |
#include "block_int.h" |
26 |
#include <zlib.h> |
27 |
#include "aes.h" |
28 |
|
29 |
/**************************************************************/
|
30 |
/* QEMU COW block driver with compression and encryption support */
|
31 |
|
32 |
#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) |
33 |
#define QCOW_VERSION 1 |
34 |
|
35 |
#define QCOW_CRYPT_NONE 0 |
36 |
#define QCOW_CRYPT_AES 1 |
37 |
|
38 |
#define QCOW_OFLAG_COMPRESSED (1LL << 63) |
39 |
|
40 |
typedef struct QCowHeader { |
41 |
uint32_t magic; |
42 |
uint32_t version; |
43 |
uint64_t backing_file_offset; |
44 |
uint32_t backing_file_size; |
45 |
uint32_t mtime; |
46 |
uint64_t size; /* in bytes */
|
47 |
uint8_t cluster_bits; |
48 |
uint8_t l2_bits; |
49 |
uint32_t crypt_method; |
50 |
uint64_t l1_table_offset; |
51 |
} QCowHeader; |
52 |
|
53 |
#define L2_CACHE_SIZE 16 |
54 |
|
55 |
typedef struct BDRVQcowState { |
56 |
int fd;
|
57 |
int cluster_bits;
|
58 |
int cluster_size;
|
59 |
int cluster_sectors;
|
60 |
int l2_bits;
|
61 |
int l2_size;
|
62 |
int l1_size;
|
63 |
uint64_t cluster_offset_mask; |
64 |
uint64_t l1_table_offset; |
65 |
uint64_t *l1_table; |
66 |
uint64_t *l2_cache; |
67 |
uint64_t l2_cache_offsets[L2_CACHE_SIZE]; |
68 |
uint32_t l2_cache_counts[L2_CACHE_SIZE]; |
69 |
uint8_t *cluster_cache; |
70 |
uint8_t *cluster_data; |
71 |
uint64_t cluster_cache_offset; |
72 |
uint32_t crypt_method; /* current crypt method, 0 if no key yet */
|
73 |
uint32_t crypt_method_header; |
74 |
AES_KEY aes_encrypt_key; |
75 |
AES_KEY aes_decrypt_key; |
76 |
} BDRVQcowState; |
77 |
|
78 |
static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset); |
79 |
|
80 |
static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) |
81 |
{ |
82 |
const QCowHeader *cow_header = (const void *)buf; |
83 |
|
84 |
if (buf_size >= sizeof(QCowHeader) && |
85 |
be32_to_cpu(cow_header->magic) == QCOW_MAGIC && |
86 |
be32_to_cpu(cow_header->version) == QCOW_VERSION) |
87 |
return 100; |
88 |
else
|
89 |
return 0; |
90 |
} |
91 |
|
92 |
static int qcow_open(BlockDriverState *bs, const char *filename) |
93 |
{ |
94 |
BDRVQcowState *s = bs->opaque; |
95 |
int fd, len, i, shift;
|
96 |
QCowHeader header; |
97 |
|
98 |
fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE); |
99 |
if (fd < 0) { |
100 |
fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE); |
101 |
if (fd < 0) |
102 |
return -1; |
103 |
} |
104 |
s->fd = fd; |
105 |
if (read(fd, &header, sizeof(header)) != sizeof(header)) |
106 |
goto fail;
|
107 |
be32_to_cpus(&header.magic); |
108 |
be32_to_cpus(&header.version); |
109 |
be64_to_cpus(&header.backing_file_offset); |
110 |
be32_to_cpus(&header.backing_file_size); |
111 |
be32_to_cpus(&header.mtime); |
112 |
be64_to_cpus(&header.size); |
113 |
be32_to_cpus(&header.crypt_method); |
114 |
be64_to_cpus(&header.l1_table_offset); |
115 |
|
116 |
if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
|
117 |
goto fail;
|
118 |
if (header.size <= 1 || header.cluster_bits < 9) |
119 |
goto fail;
|
120 |
if (header.crypt_method > QCOW_CRYPT_AES)
|
121 |
goto fail;
|
122 |
s->crypt_method_header = header.crypt_method; |
123 |
if (s->crypt_method_header)
|
124 |
bs->encrypted = 1;
|
125 |
s->cluster_bits = header.cluster_bits; |
126 |
s->cluster_size = 1 << s->cluster_bits;
|
127 |
s->cluster_sectors = 1 << (s->cluster_bits - 9); |
128 |
s->l2_bits = header.l2_bits; |
129 |
s->l2_size = 1 << s->l2_bits;
|
130 |
bs->total_sectors = header.size / 512;
|
131 |
s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; |
132 |
|
133 |
/* read the level 1 table */
|
134 |
shift = s->cluster_bits + s->l2_bits; |
135 |
s->l1_size = (header.size + (1LL << shift) - 1) >> shift; |
136 |
|
137 |
s->l1_table_offset = header.l1_table_offset; |
138 |
s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
|
139 |
if (!s->l1_table)
|
140 |
goto fail;
|
141 |
lseek(fd, s->l1_table_offset, SEEK_SET); |
142 |
if (read(fd, s->l1_table, s->l1_size * sizeof(uint64_t)) != |
143 |
s->l1_size * sizeof(uint64_t))
|
144 |
goto fail;
|
145 |
for(i = 0;i < s->l1_size; i++) { |
146 |
be64_to_cpus(&s->l1_table[i]); |
147 |
} |
148 |
/* alloc L2 cache */
|
149 |
s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
|
150 |
if (!s->l2_cache)
|
151 |
goto fail;
|
152 |
s->cluster_cache = qemu_malloc(s->cluster_size); |
153 |
if (!s->cluster_cache)
|
154 |
goto fail;
|
155 |
s->cluster_data = qemu_malloc(s->cluster_size); |
156 |
if (!s->cluster_data)
|
157 |
goto fail;
|
158 |
s->cluster_cache_offset = -1;
|
159 |
|
160 |
/* read the backing file name */
|
161 |
if (header.backing_file_offset != 0) { |
162 |
len = header.backing_file_size; |
163 |
if (len > 1023) |
164 |
len = 1023;
|
165 |
lseek(fd, header.backing_file_offset, SEEK_SET); |
166 |
if (read(fd, bs->backing_file, len) != len)
|
167 |
goto fail;
|
168 |
bs->backing_file[len] = '\0';
|
169 |
} |
170 |
return 0; |
171 |
|
172 |
fail:
|
173 |
qemu_free(s->l1_table); |
174 |
qemu_free(s->l2_cache); |
175 |
qemu_free(s->cluster_cache); |
176 |
qemu_free(s->cluster_data); |
177 |
close(fd); |
178 |
return -1; |
179 |
} |
180 |
|
181 |
static int qcow_set_key(BlockDriverState *bs, const char *key) |
182 |
{ |
183 |
BDRVQcowState *s = bs->opaque; |
184 |
uint8_t keybuf[16];
|
185 |
int len, i;
|
186 |
|
187 |
memset(keybuf, 0, 16); |
188 |
len = strlen(key); |
189 |
if (len > 16) |
190 |
len = 16;
|
191 |
/* XXX: we could compress the chars to 7 bits to increase
|
192 |
entropy */
|
193 |
for(i = 0;i < len;i++) { |
194 |
keybuf[i] = key[i]; |
195 |
} |
196 |
s->crypt_method = s->crypt_method_header; |
197 |
|
198 |
if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) |
199 |
return -1; |
200 |
if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) |
201 |
return -1; |
202 |
#if 0
|
203 |
/* test */
|
204 |
{
|
205 |
uint8_t in[16];
|
206 |
uint8_t out[16];
|
207 |
uint8_t tmp[16];
|
208 |
for(i=0;i<16;i++)
|
209 |
in[i] = i;
|
210 |
AES_encrypt(in, tmp, &s->aes_encrypt_key);
|
211 |
AES_decrypt(tmp, out, &s->aes_decrypt_key);
|
212 |
for(i = 0; i < 16; i++)
|
213 |
printf(" %02x", tmp[i]);
|
214 |
printf("\n");
|
215 |
for(i = 0; i < 16; i++)
|
216 |
printf(" %02x", out[i]);
|
217 |
printf("\n");
|
218 |
}
|
219 |
#endif
|
220 |
return 0; |
221 |
} |
222 |
|
223 |
/* The crypt function is compatible with the linux cryptoloop
|
224 |
algorithm for < 4 GB images. NOTE: out_buf == in_buf is
|
225 |
supported */
|
226 |
static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num, |
227 |
uint8_t *out_buf, const uint8_t *in_buf,
|
228 |
int nb_sectors, int enc, |
229 |
const AES_KEY *key)
|
230 |
{ |
231 |
union {
|
232 |
uint64_t ll[2];
|
233 |
uint8_t b[16];
|
234 |
} ivec; |
235 |
int i;
|
236 |
|
237 |
for(i = 0; i < nb_sectors; i++) { |
238 |
ivec.ll[0] = cpu_to_le64(sector_num);
|
239 |
ivec.ll[1] = 0; |
240 |
AES_cbc_encrypt(in_buf, out_buf, 512, key,
|
241 |
ivec.b, enc); |
242 |
sector_num++; |
243 |
in_buf += 512;
|
244 |
out_buf += 512;
|
245 |
} |
246 |
} |
247 |
|
248 |
/* 'allocate' is:
|
249 |
*
|
250 |
* 0 to not allocate.
|
251 |
*
|
252 |
* 1 to allocate a normal cluster (for sector indexes 'n_start' to
|
253 |
* 'n_end')
|
254 |
*
|
255 |
* 2 to allocate a compressed cluster of size
|
256 |
* 'compressed_size'. 'compressed_size' must be > 0 and <
|
257 |
* cluster_size
|
258 |
*
|
259 |
* return 0 if not allocated.
|
260 |
*/
|
261 |
static uint64_t get_cluster_offset(BlockDriverState *bs,
|
262 |
uint64_t offset, int allocate,
|
263 |
int compressed_size,
|
264 |
int n_start, int n_end) |
265 |
{ |
266 |
BDRVQcowState *s = bs->opaque; |
267 |
int min_index, i, j, l1_index, l2_index;
|
268 |
uint64_t l2_offset, *l2_table, cluster_offset, tmp; |
269 |
uint32_t min_count; |
270 |
int new_l2_table;
|
271 |
|
272 |
l1_index = offset >> (s->l2_bits + s->cluster_bits); |
273 |
l2_offset = s->l1_table[l1_index]; |
274 |
new_l2_table = 0;
|
275 |
if (!l2_offset) {
|
276 |
if (!allocate)
|
277 |
return 0; |
278 |
/* allocate a new l2 entry */
|
279 |
l2_offset = lseek(s->fd, 0, SEEK_END);
|
280 |
/* round to cluster size */
|
281 |
l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); |
282 |
/* update the L1 entry */
|
283 |
s->l1_table[l1_index] = l2_offset; |
284 |
tmp = cpu_to_be64(l2_offset); |
285 |
lseek(s->fd, s->l1_table_offset + l1_index * sizeof(tmp), SEEK_SET);
|
286 |
if (write(s->fd, &tmp, sizeof(tmp)) != sizeof(tmp)) |
287 |
return 0; |
288 |
new_l2_table = 1;
|
289 |
} |
290 |
for(i = 0; i < L2_CACHE_SIZE; i++) { |
291 |
if (l2_offset == s->l2_cache_offsets[i]) {
|
292 |
/* increment the hit count */
|
293 |
if (++s->l2_cache_counts[i] == 0xffffffff) { |
294 |
for(j = 0; j < L2_CACHE_SIZE; j++) { |
295 |
s->l2_cache_counts[j] >>= 1;
|
296 |
} |
297 |
} |
298 |
l2_table = s->l2_cache + (i << s->l2_bits); |
299 |
goto found;
|
300 |
} |
301 |
} |
302 |
/* not found: load a new entry in the least used one */
|
303 |
min_index = 0;
|
304 |
min_count = 0xffffffff;
|
305 |
for(i = 0; i < L2_CACHE_SIZE; i++) { |
306 |
if (s->l2_cache_counts[i] < min_count) {
|
307 |
min_count = s->l2_cache_counts[i]; |
308 |
min_index = i; |
309 |
} |
310 |
} |
311 |
l2_table = s->l2_cache + (min_index << s->l2_bits); |
312 |
lseek(s->fd, l2_offset, SEEK_SET); |
313 |
if (new_l2_table) {
|
314 |
memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); |
315 |
if (write(s->fd, l2_table, s->l2_size * sizeof(uint64_t)) != |
316 |
s->l2_size * sizeof(uint64_t))
|
317 |
return 0; |
318 |
} else {
|
319 |
if (read(s->fd, l2_table, s->l2_size * sizeof(uint64_t)) != |
320 |
s->l2_size * sizeof(uint64_t))
|
321 |
return 0; |
322 |
} |
323 |
s->l2_cache_offsets[min_index] = l2_offset; |
324 |
s->l2_cache_counts[min_index] = 1;
|
325 |
found:
|
326 |
l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
|
327 |
cluster_offset = be64_to_cpu(l2_table[l2_index]); |
328 |
if (!cluster_offset ||
|
329 |
((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
|
330 |
if (!allocate)
|
331 |
return 0; |
332 |
/* allocate a new cluster */
|
333 |
if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
|
334 |
(n_end - n_start) < s->cluster_sectors) { |
335 |
/* if the cluster is already compressed, we must
|
336 |
decompress it in the case it is not completely
|
337 |
overwritten */
|
338 |
if (decompress_cluster(s, cluster_offset) < 0) |
339 |
return 0; |
340 |
cluster_offset = lseek(s->fd, 0, SEEK_END);
|
341 |
cluster_offset = (cluster_offset + s->cluster_size - 1) &
|
342 |
~(s->cluster_size - 1);
|
343 |
/* write the cluster content */
|
344 |
lseek(s->fd, cluster_offset, SEEK_SET); |
345 |
if (write(s->fd, s->cluster_cache, s->cluster_size) !=
|
346 |
s->cluster_size) |
347 |
return -1; |
348 |
} else {
|
349 |
cluster_offset = lseek(s->fd, 0, SEEK_END);
|
350 |
if (allocate == 1) { |
351 |
/* round to cluster size */
|
352 |
cluster_offset = (cluster_offset + s->cluster_size - 1) &
|
353 |
~(s->cluster_size - 1);
|
354 |
ftruncate(s->fd, cluster_offset + s->cluster_size); |
355 |
/* if encrypted, we must initialize the cluster
|
356 |
content which won't be written */
|
357 |
if (s->crypt_method &&
|
358 |
(n_end - n_start) < s->cluster_sectors) { |
359 |
uint64_t start_sect; |
360 |
start_sect = (offset & ~(s->cluster_size - 1)) >> 9; |
361 |
memset(s->cluster_data + 512, 0xaa, 512); |
362 |
for(i = 0; i < s->cluster_sectors; i++) { |
363 |
if (i < n_start || i >= n_end) {
|
364 |
encrypt_sectors(s, start_sect + i, |
365 |
s->cluster_data, |
366 |
s->cluster_data + 512, 1, 1, |
367 |
&s->aes_encrypt_key); |
368 |
lseek(s->fd, cluster_offset + i * 512, SEEK_SET);
|
369 |
if (write(s->fd, s->cluster_data, 512) != 512) |
370 |
return -1; |
371 |
} |
372 |
} |
373 |
} |
374 |
} else {
|
375 |
cluster_offset |= QCOW_OFLAG_COMPRESSED | |
376 |
(uint64_t)compressed_size << (63 - s->cluster_bits);
|
377 |
} |
378 |
} |
379 |
/* update L2 table */
|
380 |
tmp = cpu_to_be64(cluster_offset); |
381 |
l2_table[l2_index] = tmp; |
382 |
lseek(s->fd, l2_offset + l2_index * sizeof(tmp), SEEK_SET);
|
383 |
if (write(s->fd, &tmp, sizeof(tmp)) != sizeof(tmp)) |
384 |
return 0; |
385 |
} |
386 |
return cluster_offset;
|
387 |
} |
388 |
|
389 |
static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num, |
390 |
int nb_sectors, int *pnum) |
391 |
{ |
392 |
BDRVQcowState *s = bs->opaque; |
393 |
int index_in_cluster, n;
|
394 |
uint64_t cluster_offset; |
395 |
|
396 |
cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); |
397 |
index_in_cluster = sector_num & (s->cluster_sectors - 1);
|
398 |
n = s->cluster_sectors - index_in_cluster; |
399 |
if (n > nb_sectors)
|
400 |
n = nb_sectors; |
401 |
*pnum = n; |
402 |
return (cluster_offset != 0); |
403 |
} |
404 |
|
405 |
static int decompress_buffer(uint8_t *out_buf, int out_buf_size, |
406 |
const uint8_t *buf, int buf_size) |
407 |
{ |
408 |
z_stream strm1, *strm = &strm1; |
409 |
int ret, out_len;
|
410 |
|
411 |
memset(strm, 0, sizeof(*strm)); |
412 |
|
413 |
strm->next_in = (uint8_t *)buf; |
414 |
strm->avail_in = buf_size; |
415 |
strm->next_out = out_buf; |
416 |
strm->avail_out = out_buf_size; |
417 |
|
418 |
ret = inflateInit2(strm, -12);
|
419 |
if (ret != Z_OK)
|
420 |
return -1; |
421 |
ret = inflate(strm, Z_FINISH); |
422 |
out_len = strm->next_out - out_buf; |
423 |
if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
|
424 |
out_len != out_buf_size) { |
425 |
inflateEnd(strm); |
426 |
return -1; |
427 |
} |
428 |
inflateEnd(strm); |
429 |
return 0; |
430 |
} |
431 |
|
432 |
static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset) |
433 |
{ |
434 |
int ret, csize;
|
435 |
uint64_t coffset; |
436 |
|
437 |
coffset = cluster_offset & s->cluster_offset_mask; |
438 |
if (s->cluster_cache_offset != coffset) {
|
439 |
csize = cluster_offset >> (63 - s->cluster_bits);
|
440 |
csize &= (s->cluster_size - 1);
|
441 |
lseek(s->fd, coffset, SEEK_SET); |
442 |
ret = read(s->fd, s->cluster_data, csize); |
443 |
if (ret != csize)
|
444 |
return -1; |
445 |
if (decompress_buffer(s->cluster_cache, s->cluster_size,
|
446 |
s->cluster_data, csize) < 0) {
|
447 |
return -1; |
448 |
} |
449 |
s->cluster_cache_offset = coffset; |
450 |
} |
451 |
return 0; |
452 |
} |
453 |
|
454 |
static int qcow_read(BlockDriverState *bs, int64_t sector_num, |
455 |
uint8_t *buf, int nb_sectors)
|
456 |
{ |
457 |
BDRVQcowState *s = bs->opaque; |
458 |
int ret, index_in_cluster, n;
|
459 |
uint64_t cluster_offset; |
460 |
|
461 |
while (nb_sectors > 0) { |
462 |
cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); |
463 |
index_in_cluster = sector_num & (s->cluster_sectors - 1);
|
464 |
n = s->cluster_sectors - index_in_cluster; |
465 |
if (n > nb_sectors)
|
466 |
n = nb_sectors; |
467 |
if (!cluster_offset) {
|
468 |
memset(buf, 0, 512 * n); |
469 |
} else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { |
470 |
if (decompress_cluster(s, cluster_offset) < 0) |
471 |
return -1; |
472 |
memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n); |
473 |
} else {
|
474 |
lseek(s->fd, cluster_offset + index_in_cluster * 512, SEEK_SET);
|
475 |
ret = read(s->fd, buf, n * 512);
|
476 |
if (ret != n * 512) |
477 |
return -1; |
478 |
if (s->crypt_method) {
|
479 |
encrypt_sectors(s, sector_num, buf, buf, n, 0,
|
480 |
&s->aes_decrypt_key); |
481 |
} |
482 |
} |
483 |
nb_sectors -= n; |
484 |
sector_num += n; |
485 |
buf += n * 512;
|
486 |
} |
487 |
return 0; |
488 |
} |
489 |
|
490 |
static int qcow_write(BlockDriverState *bs, int64_t sector_num, |
491 |
const uint8_t *buf, int nb_sectors) |
492 |
{ |
493 |
BDRVQcowState *s = bs->opaque; |
494 |
int ret, index_in_cluster, n;
|
495 |
uint64_t cluster_offset; |
496 |
|
497 |
while (nb_sectors > 0) { |
498 |
index_in_cluster = sector_num & (s->cluster_sectors - 1);
|
499 |
n = s->cluster_sectors - index_in_cluster; |
500 |
if (n > nb_sectors)
|
501 |
n = nb_sectors; |
502 |
cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, |
503 |
index_in_cluster, |
504 |
index_in_cluster + n); |
505 |
if (!cluster_offset)
|
506 |
return -1; |
507 |
lseek(s->fd, cluster_offset + index_in_cluster * 512, SEEK_SET);
|
508 |
if (s->crypt_method) {
|
509 |
encrypt_sectors(s, sector_num, s->cluster_data, buf, n, 1,
|
510 |
&s->aes_encrypt_key); |
511 |
ret = write(s->fd, s->cluster_data, n * 512);
|
512 |
} else {
|
513 |
ret = write(s->fd, buf, n * 512);
|
514 |
} |
515 |
if (ret != n * 512) |
516 |
return -1; |
517 |
nb_sectors -= n; |
518 |
sector_num += n; |
519 |
buf += n * 512;
|
520 |
} |
521 |
s->cluster_cache_offset = -1; /* disable compressed cache */ |
522 |
return 0; |
523 |
} |
524 |
|
525 |
static void qcow_close(BlockDriverState *bs) |
526 |
{ |
527 |
BDRVQcowState *s = bs->opaque; |
528 |
qemu_free(s->l1_table); |
529 |
qemu_free(s->l2_cache); |
530 |
qemu_free(s->cluster_cache); |
531 |
qemu_free(s->cluster_data); |
532 |
close(s->fd); |
533 |
} |
534 |
|
535 |
static int qcow_create(const char *filename, int64_t total_size, |
536 |
const char *backing_file, int flags) |
537 |
{ |
538 |
int fd, header_size, backing_filename_len, l1_size, i, shift;
|
539 |
QCowHeader header; |
540 |
char backing_filename[1024]; |
541 |
uint64_t tmp; |
542 |
struct stat st;
|
543 |
|
544 |
fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE, |
545 |
0644);
|
546 |
if (fd < 0) |
547 |
return -1; |
548 |
memset(&header, 0, sizeof(header)); |
549 |
header.magic = cpu_to_be32(QCOW_MAGIC); |
550 |
header.version = cpu_to_be32(QCOW_VERSION); |
551 |
header.size = cpu_to_be64(total_size * 512);
|
552 |
header_size = sizeof(header);
|
553 |
backing_filename_len = 0;
|
554 |
if (backing_file) {
|
555 |
const char *p; |
556 |
/* XXX: this is a hack: we do not attempt to check for URL
|
557 |
like syntax */
|
558 |
p = strchr(backing_file, ':');
|
559 |
if (p && (p - backing_file) >= 2) { |
560 |
/* URL like but exclude "c:" like filenames */
|
561 |
pstrcpy(backing_filename, sizeof(backing_filename),
|
562 |
backing_file); |
563 |
} else {
|
564 |
realpath(backing_file, backing_filename); |
565 |
if (stat(backing_filename, &st) != 0) { |
566 |
return -1; |
567 |
} |
568 |
} |
569 |
header.mtime = cpu_to_be32(st.st_mtime); |
570 |
header.backing_file_offset = cpu_to_be64(header_size); |
571 |
backing_filename_len = strlen(backing_filename); |
572 |
header.backing_file_size = cpu_to_be32(backing_filename_len); |
573 |
header_size += backing_filename_len; |
574 |
header.cluster_bits = 9; /* 512 byte cluster to avoid copying |
575 |
unmodifyed sectors */
|
576 |
header.l2_bits = 12; /* 32 KB L2 tables */ |
577 |
} else {
|
578 |
header.cluster_bits = 12; /* 4 KB clusters */ |
579 |
header.l2_bits = 9; /* 4 KB L2 tables */ |
580 |
} |
581 |
header_size = (header_size + 7) & ~7; |
582 |
shift = header.cluster_bits + header.l2_bits; |
583 |
l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift; |
584 |
|
585 |
header.l1_table_offset = cpu_to_be64(header_size); |
586 |
if (flags) {
|
587 |
header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); |
588 |
} else {
|
589 |
header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); |
590 |
} |
591 |
|
592 |
/* write all the data */
|
593 |
write(fd, &header, sizeof(header));
|
594 |
if (backing_file) {
|
595 |
write(fd, backing_filename, backing_filename_len); |
596 |
} |
597 |
lseek(fd, header_size, SEEK_SET); |
598 |
tmp = 0;
|
599 |
for(i = 0;i < l1_size; i++) { |
600 |
write(fd, &tmp, sizeof(tmp));
|
601 |
} |
602 |
close(fd); |
603 |
return 0; |
604 |
} |
605 |
|
606 |
int qcow_get_cluster_size(BlockDriverState *bs)
|
607 |
{ |
608 |
BDRVQcowState *s = bs->opaque; |
609 |
if (bs->drv != &bdrv_qcow)
|
610 |
return -1; |
611 |
return s->cluster_size;
|
612 |
} |
613 |
|
614 |
/* XXX: put compressed sectors first, then all the cluster aligned
|
615 |
tables to avoid losing bytes in alignment */
|
616 |
int qcow_compress_cluster(BlockDriverState *bs, int64_t sector_num,
|
617 |
const uint8_t *buf)
|
618 |
{ |
619 |
BDRVQcowState *s = bs->opaque; |
620 |
z_stream strm; |
621 |
int ret, out_len;
|
622 |
uint8_t *out_buf; |
623 |
uint64_t cluster_offset; |
624 |
|
625 |
if (bs->drv != &bdrv_qcow)
|
626 |
return -1; |
627 |
|
628 |
out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); |
629 |
if (!out_buf)
|
630 |
return -1; |
631 |
|
632 |
/* best compression, small window, no zlib header */
|
633 |
memset(&strm, 0, sizeof(strm)); |
634 |
ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, |
635 |
Z_DEFLATED, -12,
|
636 |
9, Z_DEFAULT_STRATEGY);
|
637 |
if (ret != 0) { |
638 |
qemu_free(out_buf); |
639 |
return -1; |
640 |
} |
641 |
|
642 |
strm.avail_in = s->cluster_size; |
643 |
strm.next_in = (uint8_t *)buf; |
644 |
strm.avail_out = s->cluster_size; |
645 |
strm.next_out = out_buf; |
646 |
|
647 |
ret = deflate(&strm, Z_FINISH); |
648 |
if (ret != Z_STREAM_END && ret != Z_OK) {
|
649 |
qemu_free(out_buf); |
650 |
deflateEnd(&strm); |
651 |
return -1; |
652 |
} |
653 |
out_len = strm.next_out - out_buf; |
654 |
|
655 |
deflateEnd(&strm); |
656 |
|
657 |
if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
|
658 |
/* could not compress: write normal cluster */
|
659 |
qcow_write(bs, sector_num, buf, s->cluster_sectors); |
660 |
} else {
|
661 |
cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, |
662 |
out_len, 0, 0); |
663 |
cluster_offset &= s->cluster_offset_mask; |
664 |
lseek(s->fd, cluster_offset, SEEK_SET); |
665 |
if (write(s->fd, out_buf, out_len) != out_len) {
|
666 |
qemu_free(out_buf); |
667 |
return -1; |
668 |
} |
669 |
} |
670 |
|
671 |
qemu_free(out_buf); |
672 |
return 0; |
673 |
} |
674 |
|
675 |
BlockDriver bdrv_qcow = { |
676 |
"qcow",
|
677 |
sizeof(BDRVQcowState),
|
678 |
qcow_probe, |
679 |
qcow_open, |
680 |
qcow_read, |
681 |
qcow_write, |
682 |
qcow_close, |
683 |
qcow_create, |
684 |
qcow_is_allocated, |
685 |
qcow_set_key, |
686 |
}; |
687 |
|
688 |
|