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1.1 root 1: /*
2: * Block driver for the QCOW format
3: *
4: * Copyright (c) 2004-2006 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 "qemu-common.h"
25: #include "block_int.h"
26: #include "module.h"
27: #include <zlib.h>
28: #include "aes.h"
29:
30: /**************************************************************/
31: /* QEMU COW block driver with compression and encryption support */
32:
33: #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
34: #define QCOW_VERSION 1
35:
36: #define QCOW_CRYPT_NONE 0
37: #define QCOW_CRYPT_AES 1
38:
39: #define QCOW_OFLAG_COMPRESSED (1LL << 63)
40:
41: typedef struct QCowHeader {
42: uint32_t magic;
43: uint32_t version;
44: uint64_t backing_file_offset;
45: uint32_t backing_file_size;
46: uint32_t mtime;
47: uint64_t size; /* in bytes */
48: uint8_t cluster_bits;
49: uint8_t l2_bits;
50: uint32_t crypt_method;
51: uint64_t l1_table_offset;
52: } QCowHeader;
53:
54: #define L2_CACHE_SIZE 16
55:
56: typedef struct BDRVQcowState {
57: BlockDriverState *hd;
58: int cluster_bits;
59: int cluster_size;
60: int cluster_sectors;
61: int l2_bits;
62: int l2_size;
63: int l1_size;
64: uint64_t cluster_offset_mask;
65: uint64_t l1_table_offset;
66: uint64_t *l1_table;
67: uint64_t *l2_cache;
68: uint64_t l2_cache_offsets[L2_CACHE_SIZE];
69: uint32_t l2_cache_counts[L2_CACHE_SIZE];
70: uint8_t *cluster_cache;
71: uint8_t *cluster_data;
72: uint64_t cluster_cache_offset;
73: uint32_t crypt_method; /* current crypt method, 0 if no key yet */
74: uint32_t crypt_method_header;
75: AES_KEY aes_encrypt_key;
76: AES_KEY aes_decrypt_key;
77: } BDRVQcowState;
78:
79: static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset);
80:
81: static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
82: {
83: const QCowHeader *cow_header = (const void *)buf;
84:
85: if (buf_size >= sizeof(QCowHeader) &&
86: be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
87: be32_to_cpu(cow_header->version) == QCOW_VERSION)
88: return 100;
89: else
90: return 0;
91: }
92:
93: static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
94: {
95: BDRVQcowState *s = bs->opaque;
96: int len, i, shift, ret;
97: QCowHeader header;
98:
99: ret = bdrv_file_open(&s->hd, filename, flags);
100: if (ret < 0)
101: return ret;
102: if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header))
103: goto fail;
104: be32_to_cpus(&header.magic);
105: be32_to_cpus(&header.version);
106: be64_to_cpus(&header.backing_file_offset);
107: be32_to_cpus(&header.backing_file_size);
108: be32_to_cpus(&header.mtime);
109: be64_to_cpus(&header.size);
110: be32_to_cpus(&header.crypt_method);
111: be64_to_cpus(&header.l1_table_offset);
112:
113: if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
114: goto fail;
115: if (header.size <= 1 || header.cluster_bits < 9)
116: goto fail;
117: if (header.crypt_method > QCOW_CRYPT_AES)
118: goto fail;
119: s->crypt_method_header = header.crypt_method;
120: if (s->crypt_method_header)
121: bs->encrypted = 1;
122: s->cluster_bits = header.cluster_bits;
123: s->cluster_size = 1 << s->cluster_bits;
124: s->cluster_sectors = 1 << (s->cluster_bits - 9);
125: s->l2_bits = header.l2_bits;
126: s->l2_size = 1 << s->l2_bits;
127: bs->total_sectors = header.size / 512;
128: s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
129:
130: /* read the level 1 table */
131: shift = s->cluster_bits + s->l2_bits;
132: s->l1_size = (header.size + (1LL << shift) - 1) >> shift;
133:
134: s->l1_table_offset = header.l1_table_offset;
135: s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
136: if (!s->l1_table)
137: goto fail;
138: if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
139: s->l1_size * sizeof(uint64_t))
140: goto fail;
141: for(i = 0;i < s->l1_size; i++) {
142: be64_to_cpus(&s->l1_table[i]);
143: }
144: /* alloc L2 cache */
145: s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
146: if (!s->l2_cache)
147: goto fail;
148: s->cluster_cache = qemu_malloc(s->cluster_size);
149: if (!s->cluster_cache)
150: goto fail;
151: s->cluster_data = qemu_malloc(s->cluster_size);
152: if (!s->cluster_data)
153: goto fail;
154: s->cluster_cache_offset = -1;
155:
156: /* read the backing file name */
157: if (header.backing_file_offset != 0) {
158: len = header.backing_file_size;
159: if (len > 1023)
160: len = 1023;
161: if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)
162: goto fail;
163: bs->backing_file[len] = '\0';
164: }
165: return 0;
166:
167: fail:
168: qemu_free(s->l1_table);
169: qemu_free(s->l2_cache);
170: qemu_free(s->cluster_cache);
171: qemu_free(s->cluster_data);
172: bdrv_delete(s->hd);
173: return -1;
174: }
175:
176: static int qcow_set_key(BlockDriverState *bs, const char *key)
177: {
178: BDRVQcowState *s = bs->opaque;
179: uint8_t keybuf[16];
180: int len, i;
181:
182: memset(keybuf, 0, 16);
183: len = strlen(key);
184: if (len > 16)
185: len = 16;
186: /* XXX: we could compress the chars to 7 bits to increase
187: entropy */
188: for(i = 0;i < len;i++) {
189: keybuf[i] = key[i];
190: }
191: s->crypt_method = s->crypt_method_header;
192:
193: if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
194: return -1;
195: if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
196: return -1;
197: #if 0
198: /* test */
199: {
200: uint8_t in[16];
201: uint8_t out[16];
202: uint8_t tmp[16];
203: for(i=0;i<16;i++)
204: in[i] = i;
205: AES_encrypt(in, tmp, &s->aes_encrypt_key);
206: AES_decrypt(tmp, out, &s->aes_decrypt_key);
207: for(i = 0; i < 16; i++)
208: printf(" %02x", tmp[i]);
209: printf("\n");
210: for(i = 0; i < 16; i++)
211: printf(" %02x", out[i]);
212: printf("\n");
213: }
214: #endif
215: return 0;
216: }
217:
218: /* The crypt function is compatible with the linux cryptoloop
219: algorithm for < 4 GB images. NOTE: out_buf == in_buf is
220: supported */
221: static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
222: uint8_t *out_buf, const uint8_t *in_buf,
223: int nb_sectors, int enc,
224: const AES_KEY *key)
225: {
226: union {
227: uint64_t ll[2];
228: uint8_t b[16];
229: } ivec;
230: int i;
231:
232: for(i = 0; i < nb_sectors; i++) {
233: ivec.ll[0] = cpu_to_le64(sector_num);
234: ivec.ll[1] = 0;
235: AES_cbc_encrypt(in_buf, out_buf, 512, key,
236: ivec.b, enc);
237: sector_num++;
238: in_buf += 512;
239: out_buf += 512;
240: }
241: }
242:
243: /* 'allocate' is:
244: *
245: * 0 to not allocate.
246: *
247: * 1 to allocate a normal cluster (for sector indexes 'n_start' to
248: * 'n_end')
249: *
250: * 2 to allocate a compressed cluster of size
251: * 'compressed_size'. 'compressed_size' must be > 0 and <
252: * cluster_size
253: *
254: * return 0 if not allocated.
255: */
256: static uint64_t get_cluster_offset(BlockDriverState *bs,
257: uint64_t offset, int allocate,
258: int compressed_size,
259: int n_start, int n_end)
260: {
261: BDRVQcowState *s = bs->opaque;
262: int min_index, i, j, l1_index, l2_index;
263: uint64_t l2_offset, *l2_table, cluster_offset, tmp;
264: uint32_t min_count;
265: int new_l2_table;
266:
267: l1_index = offset >> (s->l2_bits + s->cluster_bits);
268: l2_offset = s->l1_table[l1_index];
269: new_l2_table = 0;
270: if (!l2_offset) {
271: if (!allocate)
272: return 0;
273: /* allocate a new l2 entry */
274: l2_offset = bdrv_getlength(s->hd);
275: /* round to cluster size */
276: l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
277: /* update the L1 entry */
278: s->l1_table[l1_index] = l2_offset;
279: tmp = cpu_to_be64(l2_offset);
280: if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp),
281: &tmp, sizeof(tmp)) != sizeof(tmp))
282: return 0;
283: new_l2_table = 1;
284: }
285: for(i = 0; i < L2_CACHE_SIZE; i++) {
286: if (l2_offset == s->l2_cache_offsets[i]) {
287: /* increment the hit count */
288: if (++s->l2_cache_counts[i] == 0xffffffff) {
289: for(j = 0; j < L2_CACHE_SIZE; j++) {
290: s->l2_cache_counts[j] >>= 1;
291: }
292: }
293: l2_table = s->l2_cache + (i << s->l2_bits);
294: goto found;
295: }
296: }
297: /* not found: load a new entry in the least used one */
298: min_index = 0;
299: min_count = 0xffffffff;
300: for(i = 0; i < L2_CACHE_SIZE; i++) {
301: if (s->l2_cache_counts[i] < min_count) {
302: min_count = s->l2_cache_counts[i];
303: min_index = i;
304: }
305: }
306: l2_table = s->l2_cache + (min_index << s->l2_bits);
307: if (new_l2_table) {
308: memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
309: if (bdrv_pwrite(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
310: s->l2_size * sizeof(uint64_t))
311: return 0;
312: } else {
313: if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
314: s->l2_size * sizeof(uint64_t))
315: return 0;
316: }
317: s->l2_cache_offsets[min_index] = l2_offset;
318: s->l2_cache_counts[min_index] = 1;
319: found:
320: l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
321: cluster_offset = be64_to_cpu(l2_table[l2_index]);
322: if (!cluster_offset ||
323: ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
324: if (!allocate)
325: return 0;
326: /* allocate a new cluster */
327: if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
328: (n_end - n_start) < s->cluster_sectors) {
329: /* if the cluster is already compressed, we must
330: decompress it in the case it is not completely
331: overwritten */
332: if (decompress_cluster(s, cluster_offset) < 0)
333: return 0;
334: cluster_offset = bdrv_getlength(s->hd);
335: cluster_offset = (cluster_offset + s->cluster_size - 1) &
336: ~(s->cluster_size - 1);
337: /* write the cluster content */
338: if (bdrv_pwrite(s->hd, cluster_offset, s->cluster_cache, s->cluster_size) !=
339: s->cluster_size)
340: return -1;
341: } else {
342: cluster_offset = bdrv_getlength(s->hd);
343: if (allocate == 1) {
344: /* round to cluster size */
345: cluster_offset = (cluster_offset + s->cluster_size - 1) &
346: ~(s->cluster_size - 1);
347: bdrv_truncate(s->hd, cluster_offset + s->cluster_size);
348: /* if encrypted, we must initialize the cluster
349: content which won't be written */
350: if (s->crypt_method &&
351: (n_end - n_start) < s->cluster_sectors) {
352: uint64_t start_sect;
353: start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
354: memset(s->cluster_data + 512, 0x00, 512);
355: for(i = 0; i < s->cluster_sectors; i++) {
356: if (i < n_start || i >= n_end) {
357: encrypt_sectors(s, start_sect + i,
358: s->cluster_data,
359: s->cluster_data + 512, 1, 1,
360: &s->aes_encrypt_key);
361: if (bdrv_pwrite(s->hd, cluster_offset + i * 512,
362: s->cluster_data, 512) != 512)
363: return -1;
364: }
365: }
366: }
367: } else if (allocate == 2) {
368: cluster_offset |= QCOW_OFLAG_COMPRESSED |
369: (uint64_t)compressed_size << (63 - s->cluster_bits);
370: }
371: }
372: /* update L2 table */
373: tmp = cpu_to_be64(cluster_offset);
374: l2_table[l2_index] = tmp;
375: if (bdrv_pwrite(s->hd,
376: l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) != sizeof(tmp))
377: return 0;
378: }
379: return cluster_offset;
380: }
381:
382: static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
383: int nb_sectors, int *pnum)
384: {
385: BDRVQcowState *s = bs->opaque;
386: int index_in_cluster, n;
387: uint64_t cluster_offset;
388:
389: cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
390: index_in_cluster = sector_num & (s->cluster_sectors - 1);
391: n = s->cluster_sectors - index_in_cluster;
392: if (n > nb_sectors)
393: n = nb_sectors;
394: *pnum = n;
395: return (cluster_offset != 0);
396: }
397:
398: static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
399: const uint8_t *buf, int buf_size)
400: {
401: z_stream strm1, *strm = &strm1;
402: int ret, out_len;
403:
404: memset(strm, 0, sizeof(*strm));
405:
406: strm->next_in = (uint8_t *)buf;
407: strm->avail_in = buf_size;
408: strm->next_out = out_buf;
409: strm->avail_out = out_buf_size;
410:
411: ret = inflateInit2(strm, -12);
412: if (ret != Z_OK)
413: return -1;
414: ret = inflate(strm, Z_FINISH);
415: out_len = strm->next_out - out_buf;
416: if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
417: out_len != out_buf_size) {
418: inflateEnd(strm);
419: return -1;
420: }
421: inflateEnd(strm);
422: return 0;
423: }
424:
425: static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset)
426: {
427: int ret, csize;
428: uint64_t coffset;
429:
430: coffset = cluster_offset & s->cluster_offset_mask;
431: if (s->cluster_cache_offset != coffset) {
432: csize = cluster_offset >> (63 - s->cluster_bits);
433: csize &= (s->cluster_size - 1);
434: ret = bdrv_pread(s->hd, coffset, s->cluster_data, csize);
435: if (ret != csize)
436: return -1;
437: if (decompress_buffer(s->cluster_cache, s->cluster_size,
438: s->cluster_data, csize) < 0) {
439: return -1;
440: }
441: s->cluster_cache_offset = coffset;
442: }
443: return 0;
444: }
445:
446: #if 0
447:
448: static int qcow_read(BlockDriverState *bs, int64_t sector_num,
449: uint8_t *buf, int nb_sectors)
450: {
451: BDRVQcowState *s = bs->opaque;
452: int ret, index_in_cluster, n;
453: uint64_t cluster_offset;
454:
455: while (nb_sectors > 0) {
456: cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
457: index_in_cluster = sector_num & (s->cluster_sectors - 1);
458: n = s->cluster_sectors - index_in_cluster;
459: if (n > nb_sectors)
460: n = nb_sectors;
461: if (!cluster_offset) {
462: if (bs->backing_hd) {
463: /* read from the base image */
464: ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
465: if (ret < 0)
466: return -1;
467: } else {
468: memset(buf, 0, 512 * n);
469: }
470: } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
471: if (decompress_cluster(s, cluster_offset) < 0)
472: return -1;
473: memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
474: } else {
475: ret = bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, 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: #endif
490:
491: typedef struct QCowAIOCB {
492: BlockDriverAIOCB common;
493: int64_t sector_num;
494: QEMUIOVector *qiov;
495: uint8_t *buf;
496: void *orig_buf;
497: int nb_sectors;
498: int n;
499: uint64_t cluster_offset;
500: uint8_t *cluster_data;
501: struct iovec hd_iov;
502: QEMUIOVector hd_qiov;
503: BlockDriverAIOCB *hd_aiocb;
504: } QCowAIOCB;
505:
506: static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
507: {
508: QCowAIOCB *acb = (QCowAIOCB *)blockacb;
509: if (acb->hd_aiocb)
510: bdrv_aio_cancel(acb->hd_aiocb);
511: qemu_aio_release(acb);
512: }
513:
514: static AIOPool qcow_aio_pool = {
515: .aiocb_size = sizeof(QCowAIOCB),
516: .cancel = qcow_aio_cancel,
517: };
518:
519: static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
520: int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
521: BlockDriverCompletionFunc *cb, void *opaque, int is_write)
522: {
523: QCowAIOCB *acb;
524:
525: acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque);
526: if (!acb)
527: return NULL;
528: acb->hd_aiocb = NULL;
529: acb->sector_num = sector_num;
530: acb->qiov = qiov;
531: if (qiov->niov > 1) {
532: acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size);
533: if (is_write)
534: qemu_iovec_to_buffer(qiov, acb->buf);
535: } else {
536: acb->buf = (uint8_t *)qiov->iov->iov_base;
537: }
538: acb->nb_sectors = nb_sectors;
539: acb->n = 0;
540: acb->cluster_offset = 0;
541: return acb;
542: }
543:
544: static void qcow_aio_read_cb(void *opaque, int ret)
545: {
546: QCowAIOCB *acb = opaque;
547: BlockDriverState *bs = acb->common.bs;
548: BDRVQcowState *s = bs->opaque;
549: int index_in_cluster;
550:
551: acb->hd_aiocb = NULL;
552: if (ret < 0)
553: goto done;
554:
555: redo:
556: /* post process the read buffer */
557: if (!acb->cluster_offset) {
558: /* nothing to do */
559: } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
560: /* nothing to do */
561: } else {
562: if (s->crypt_method) {
563: encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf,
564: acb->n, 0,
565: &s->aes_decrypt_key);
566: }
567: }
568:
569: acb->nb_sectors -= acb->n;
570: acb->sector_num += acb->n;
571: acb->buf += acb->n * 512;
572:
573: if (acb->nb_sectors == 0) {
574: /* request completed */
575: ret = 0;
576: goto done;
577: }
578:
579: /* prepare next AIO request */
580: acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9,
581: 0, 0, 0, 0);
582: index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
583: acb->n = s->cluster_sectors - index_in_cluster;
584: if (acb->n > acb->nb_sectors)
585: acb->n = acb->nb_sectors;
586:
587: if (!acb->cluster_offset) {
588: if (bs->backing_hd) {
589: /* read from the base image */
590: acb->hd_iov.iov_base = (void *)acb->buf;
591: acb->hd_iov.iov_len = acb->n * 512;
592: qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
593: acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num,
594: &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
595: if (acb->hd_aiocb == NULL)
596: goto done;
597: } else {
598: /* Note: in this case, no need to wait */
599: memset(acb->buf, 0, 512 * acb->n);
600: goto redo;
601: }
602: } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
603: /* add AIO support for compressed blocks ? */
604: if (decompress_cluster(s, acb->cluster_offset) < 0)
605: goto done;
606: memcpy(acb->buf,
607: s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
608: goto redo;
609: } else {
610: if ((acb->cluster_offset & 511) != 0) {
611: ret = -EIO;
612: goto done;
613: }
614: acb->hd_iov.iov_base = (void *)acb->buf;
615: acb->hd_iov.iov_len = acb->n * 512;
616: qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
617: acb->hd_aiocb = bdrv_aio_readv(s->hd,
618: (acb->cluster_offset >> 9) + index_in_cluster,
619: &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
620: if (acb->hd_aiocb == NULL)
621: goto done;
622: }
623:
624: return;
625:
626: done:
627: if (acb->qiov->niov > 1) {
628: qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size);
629: qemu_vfree(acb->orig_buf);
630: }
631: acb->common.cb(acb->common.opaque, ret);
632: qemu_aio_release(acb);
633: }
634:
635: static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs,
636: int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
637: BlockDriverCompletionFunc *cb, void *opaque)
638: {
639: QCowAIOCB *acb;
640:
641: acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
642: if (!acb)
643: return NULL;
644:
645: qcow_aio_read_cb(acb, 0);
646: return &acb->common;
647: }
648:
649: static void qcow_aio_write_cb(void *opaque, int ret)
650: {
651: QCowAIOCB *acb = opaque;
652: BlockDriverState *bs = acb->common.bs;
653: BDRVQcowState *s = bs->opaque;
654: int index_in_cluster;
655: uint64_t cluster_offset;
656: const uint8_t *src_buf;
657:
658: acb->hd_aiocb = NULL;
659:
660: if (ret < 0)
661: goto done;
662:
663: acb->nb_sectors -= acb->n;
664: acb->sector_num += acb->n;
665: acb->buf += acb->n * 512;
666:
667: if (acb->nb_sectors == 0) {
668: /* request completed */
669: ret = 0;
670: goto done;
671: }
672:
673: index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
674: acb->n = s->cluster_sectors - index_in_cluster;
675: if (acb->n > acb->nb_sectors)
676: acb->n = acb->nb_sectors;
677: cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 1, 0,
678: index_in_cluster,
679: index_in_cluster + acb->n);
680: if (!cluster_offset || (cluster_offset & 511) != 0) {
681: ret = -EIO;
682: goto done;
683: }
684: if (s->crypt_method) {
685: if (!acb->cluster_data) {
686: acb->cluster_data = qemu_mallocz(s->cluster_size);
687: if (!acb->cluster_data) {
688: ret = -ENOMEM;
689: goto done;
690: }
691: }
692: encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
693: acb->n, 1, &s->aes_encrypt_key);
694: src_buf = acb->cluster_data;
695: } else {
696: src_buf = acb->buf;
697: }
698:
699: acb->hd_iov.iov_base = (void *)src_buf;
700: acb->hd_iov.iov_len = acb->n * 512;
701: qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
702: acb->hd_aiocb = bdrv_aio_writev(s->hd,
703: (cluster_offset >> 9) + index_in_cluster,
704: &acb->hd_qiov, acb->n,
705: qcow_aio_write_cb, acb);
706: if (acb->hd_aiocb == NULL)
707: goto done;
708: return;
709:
710: done:
711: if (acb->qiov->niov > 1)
712: qemu_vfree(acb->orig_buf);
713: acb->common.cb(acb->common.opaque, ret);
714: qemu_aio_release(acb);
715: }
716:
717: static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
718: int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
719: BlockDriverCompletionFunc *cb, void *opaque)
720: {
721: BDRVQcowState *s = bs->opaque;
722: QCowAIOCB *acb;
723:
724: s->cluster_cache_offset = -1; /* disable compressed cache */
725:
726: acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
727: if (!acb)
728: return NULL;
729:
730:
731: qcow_aio_write_cb(acb, 0);
732: return &acb->common;
733: }
734:
735: static void qcow_close(BlockDriverState *bs)
736: {
737: BDRVQcowState *s = bs->opaque;
738: qemu_free(s->l1_table);
739: qemu_free(s->l2_cache);
740: qemu_free(s->cluster_cache);
741: qemu_free(s->cluster_data);
742: bdrv_delete(s->hd);
743: }
744:
745: static int qcow_create(const char *filename, QEMUOptionParameter *options)
746: {
747: int fd, header_size, backing_filename_len, l1_size, i, shift;
748: QCowHeader header;
749: uint64_t tmp;
750: int64_t total_size = 0;
751: const char *backing_file = NULL;
752: int flags = 0;
753:
754: /* Read out options */
755: while (options && options->name) {
756: if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
757: total_size = options->value.n / 512;
758: } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
759: backing_file = options->value.s;
760: } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) {
761: flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
762: }
763: options++;
764: }
765:
766: fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
767: if (fd < 0)
768: return -1;
769: memset(&header, 0, sizeof(header));
770: header.magic = cpu_to_be32(QCOW_MAGIC);
771: header.version = cpu_to_be32(QCOW_VERSION);
772: header.size = cpu_to_be64(total_size * 512);
773: header_size = sizeof(header);
774: backing_filename_len = 0;
775: if (backing_file) {
776: if (strcmp(backing_file, "fat:")) {
777: header.backing_file_offset = cpu_to_be64(header_size);
778: backing_filename_len = strlen(backing_file);
779: header.backing_file_size = cpu_to_be32(backing_filename_len);
780: header_size += backing_filename_len;
781: } else {
782: /* special backing file for vvfat */
783: backing_file = NULL;
784: }
785: header.cluster_bits = 9; /* 512 byte cluster to avoid copying
786: unmodifyed sectors */
787: header.l2_bits = 12; /* 32 KB L2 tables */
788: } else {
789: header.cluster_bits = 12; /* 4 KB clusters */
790: header.l2_bits = 9; /* 4 KB L2 tables */
791: }
792: header_size = (header_size + 7) & ~7;
793: shift = header.cluster_bits + header.l2_bits;
794: l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift;
795:
796: header.l1_table_offset = cpu_to_be64(header_size);
797: if (flags & BLOCK_FLAG_ENCRYPT) {
798: header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
799: } else {
800: header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
801: }
802:
803: /* write all the data */
804: write(fd, &header, sizeof(header));
805: if (backing_file) {
806: write(fd, backing_file, backing_filename_len);
807: }
808: lseek(fd, header_size, SEEK_SET);
809: tmp = 0;
810: for(i = 0;i < l1_size; i++) {
811: write(fd, &tmp, sizeof(tmp));
812: }
813: close(fd);
814: return 0;
815: }
816:
817: static int qcow_make_empty(BlockDriverState *bs)
818: {
819: BDRVQcowState *s = bs->opaque;
820: uint32_t l1_length = s->l1_size * sizeof(uint64_t);
821: int ret;
822:
823: memset(s->l1_table, 0, l1_length);
824: if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
825: return -1;
826: ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
827: if (ret < 0)
828: return ret;
829:
830: memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
831: memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
832: memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
833:
834: return 0;
835: }
836:
837: /* XXX: put compressed sectors first, then all the cluster aligned
838: tables to avoid losing bytes in alignment */
839: static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
840: const uint8_t *buf, int nb_sectors)
841: {
842: BDRVQcowState *s = bs->opaque;
843: z_stream strm;
844: int ret, out_len;
845: uint8_t *out_buf;
846: uint64_t cluster_offset;
847:
848: if (nb_sectors != s->cluster_sectors)
849: return -EINVAL;
850:
851: out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
852: if (!out_buf)
853: return -1;
854:
855: /* best compression, small window, no zlib header */
856: memset(&strm, 0, sizeof(strm));
857: ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
858: Z_DEFLATED, -12,
859: 9, Z_DEFAULT_STRATEGY);
860: if (ret != 0) {
861: qemu_free(out_buf);
862: return -1;
863: }
864:
865: strm.avail_in = s->cluster_size;
866: strm.next_in = (uint8_t *)buf;
867: strm.avail_out = s->cluster_size;
868: strm.next_out = out_buf;
869:
870: ret = deflate(&strm, Z_FINISH);
871: if (ret != Z_STREAM_END && ret != Z_OK) {
872: qemu_free(out_buf);
873: deflateEnd(&strm);
874: return -1;
875: }
876: out_len = strm.next_out - out_buf;
877:
878: deflateEnd(&strm);
879:
880: if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
881: /* could not compress: write normal cluster */
882: bdrv_write(bs, sector_num, buf, s->cluster_sectors);
883: } else {
884: cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
885: out_len, 0, 0);
886: cluster_offset &= s->cluster_offset_mask;
887: if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
888: qemu_free(out_buf);
889: return -1;
890: }
891: }
892:
893: qemu_free(out_buf);
894: return 0;
895: }
896:
897: static void qcow_flush(BlockDriverState *bs)
898: {
899: BDRVQcowState *s = bs->opaque;
900: bdrv_flush(s->hd);
901: }
902:
903: static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
904: {
905: BDRVQcowState *s = bs->opaque;
906: bdi->cluster_size = s->cluster_size;
907: return 0;
908: }
909:
910:
911: static QEMUOptionParameter qcow_create_options[] = {
912: {
913: .name = BLOCK_OPT_SIZE,
914: .type = OPT_SIZE,
915: .help = "Virtual disk size"
916: },
917: {
918: .name = BLOCK_OPT_BACKING_FILE,
919: .type = OPT_STRING,
920: .help = "File name of a base image"
921: },
922: {
923: .name = BLOCK_OPT_ENCRYPT,
924: .type = OPT_FLAG,
925: .help = "Encrypt the image"
926: },
927: { NULL }
928: };
929:
930: static BlockDriver bdrv_qcow = {
931: .format_name = "qcow",
932: .instance_size = sizeof(BDRVQcowState),
933: .bdrv_probe = qcow_probe,
934: .bdrv_open = qcow_open,
935: .bdrv_close = qcow_close,
936: .bdrv_create = qcow_create,
937: .bdrv_flush = qcow_flush,
938: .bdrv_is_allocated = qcow_is_allocated,
939: .bdrv_set_key = qcow_set_key,
940: .bdrv_make_empty = qcow_make_empty,
941: .bdrv_aio_readv = qcow_aio_readv,
942: .bdrv_aio_writev = qcow_aio_writev,
943: .bdrv_write_compressed = qcow_write_compressed,
944: .bdrv_get_info = qcow_get_info,
945:
946: .create_options = qcow_create_options,
947: };
948:
949: static void bdrv_qcow_init(void)
950: {
951: bdrv_register(&bdrv_qcow);
952: }
953:
954: block_init(bdrv_qcow_init);
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