Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2017-03-16' into staging
[qemu.git] / block / cloop.c
1 /*
2 * QEMU Block driver for CLOOP images
3 *
4 * Copyright (c) 2004 Johannes E. Schindelin
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/osdep.h"
25 #include "qapi/error.h"
26 #include "qemu-common.h"
27 #include "block/block_int.h"
28 #include "qemu/module.h"
29 #include "qemu/bswap.h"
30 #include <zlib.h>
31
32 /* Maximum compressed block size */
33 #define MAX_BLOCK_SIZE (64 * 1024 * 1024)
34
35 typedef struct BDRVCloopState {
36 CoMutex lock;
37 uint32_t block_size;
38 uint32_t n_blocks;
39 uint64_t *offsets;
40 uint32_t sectors_per_block;
41 uint32_t current_block;
42 uint8_t *compressed_block;
43 uint8_t *uncompressed_block;
44 z_stream zstream;
45 } BDRVCloopState;
46
47 static int cloop_probe(const uint8_t *buf, int buf_size, const char *filename)
48 {
49 const char *magic_version_2_0 = "#!/bin/sh\n"
50 "#V2.0 Format\n"
51 "modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n";
52 int length = strlen(magic_version_2_0);
53 if (length > buf_size) {
54 length = buf_size;
55 }
56 if (!memcmp(magic_version_2_0, buf, length)) {
57 return 2;
58 }
59 return 0;
60 }
61
62 static int cloop_open(BlockDriverState *bs, QDict *options, int flags,
63 Error **errp)
64 {
65 BDRVCloopState *s = bs->opaque;
66 uint32_t offsets_size, max_compressed_block_size = 1, i;
67 int ret;
68
69 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
70 false, errp);
71 if (!bs->file) {
72 return -EINVAL;
73 }
74
75 bs->read_only = true;
76
77 /* read header */
78 ret = bdrv_pread(bs->file, 128, &s->block_size, 4);
79 if (ret < 0) {
80 return ret;
81 }
82 s->block_size = be32_to_cpu(s->block_size);
83 if (s->block_size % 512) {
84 error_setg(errp, "block_size %" PRIu32 " must be a multiple of 512",
85 s->block_size);
86 return -EINVAL;
87 }
88 if (s->block_size == 0) {
89 error_setg(errp, "block_size cannot be zero");
90 return -EINVAL;
91 }
92
93 /* cloop's create_compressed_fs.c warns about block sizes beyond 256 KB but
94 * we can accept more. Prevent ridiculous values like 4 GB - 1 since we
95 * need a buffer this big.
96 */
97 if (s->block_size > MAX_BLOCK_SIZE) {
98 error_setg(errp, "block_size %" PRIu32 " must be %u MB or less",
99 s->block_size,
100 MAX_BLOCK_SIZE / (1024 * 1024));
101 return -EINVAL;
102 }
103
104 ret = bdrv_pread(bs->file, 128 + 4, &s->n_blocks, 4);
105 if (ret < 0) {
106 return ret;
107 }
108 s->n_blocks = be32_to_cpu(s->n_blocks);
109
110 /* read offsets */
111 if (s->n_blocks > (UINT32_MAX - 1) / sizeof(uint64_t)) {
112 /* Prevent integer overflow */
113 error_setg(errp, "n_blocks %" PRIu32 " must be %zu or less",
114 s->n_blocks,
115 (UINT32_MAX - 1) / sizeof(uint64_t));
116 return -EINVAL;
117 }
118 offsets_size = (s->n_blocks + 1) * sizeof(uint64_t);
119 if (offsets_size > 512 * 1024 * 1024) {
120 /* Prevent ridiculous offsets_size which causes memory allocation to
121 * fail or overflows bdrv_pread() size. In practice the 512 MB
122 * offsets[] limit supports 16 TB images at 256 KB block size.
123 */
124 error_setg(errp, "image requires too many offsets, "
125 "try increasing block size");
126 return -EINVAL;
127 }
128
129 s->offsets = g_try_malloc(offsets_size);
130 if (s->offsets == NULL) {
131 error_setg(errp, "Could not allocate offsets table");
132 return -ENOMEM;
133 }
134
135 ret = bdrv_pread(bs->file, 128 + 4 + 4, s->offsets, offsets_size);
136 if (ret < 0) {
137 goto fail;
138 }
139
140 for (i = 0; i < s->n_blocks + 1; i++) {
141 uint64_t size;
142
143 s->offsets[i] = be64_to_cpu(s->offsets[i]);
144 if (i == 0) {
145 continue;
146 }
147
148 if (s->offsets[i] < s->offsets[i - 1]) {
149 error_setg(errp, "offsets not monotonically increasing at "
150 "index %" PRIu32 ", image file is corrupt", i);
151 ret = -EINVAL;
152 goto fail;
153 }
154
155 size = s->offsets[i] - s->offsets[i - 1];
156
157 /* Compressed blocks should be smaller than the uncompressed block size
158 * but maybe compression performed poorly so the compressed block is
159 * actually bigger. Clamp down on unrealistic values to prevent
160 * ridiculous s->compressed_block allocation.
161 */
162 if (size > 2 * MAX_BLOCK_SIZE) {
163 error_setg(errp, "invalid compressed block size at index %" PRIu32
164 ", image file is corrupt", i);
165 ret = -EINVAL;
166 goto fail;
167 }
168
169 if (size > max_compressed_block_size) {
170 max_compressed_block_size = size;
171 }
172 }
173
174 /* initialize zlib engine */
175 s->compressed_block = g_try_malloc(max_compressed_block_size + 1);
176 if (s->compressed_block == NULL) {
177 error_setg(errp, "Could not allocate compressed_block");
178 ret = -ENOMEM;
179 goto fail;
180 }
181
182 s->uncompressed_block = g_try_malloc(s->block_size);
183 if (s->uncompressed_block == NULL) {
184 error_setg(errp, "Could not allocate uncompressed_block");
185 ret = -ENOMEM;
186 goto fail;
187 }
188
189 if (inflateInit(&s->zstream) != Z_OK) {
190 ret = -EINVAL;
191 goto fail;
192 }
193 s->current_block = s->n_blocks;
194
195 s->sectors_per_block = s->block_size/512;
196 bs->total_sectors = s->n_blocks * s->sectors_per_block;
197 qemu_co_mutex_init(&s->lock);
198 return 0;
199
200 fail:
201 g_free(s->offsets);
202 g_free(s->compressed_block);
203 g_free(s->uncompressed_block);
204 return ret;
205 }
206
207 static void cloop_refresh_limits(BlockDriverState *bs, Error **errp)
208 {
209 bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */
210 }
211
212 static inline int cloop_read_block(BlockDriverState *bs, int block_num)
213 {
214 BDRVCloopState *s = bs->opaque;
215
216 if (s->current_block != block_num) {
217 int ret;
218 uint32_t bytes = s->offsets[block_num + 1] - s->offsets[block_num];
219
220 ret = bdrv_pread(bs->file, s->offsets[block_num],
221 s->compressed_block, bytes);
222 if (ret != bytes) {
223 return -1;
224 }
225
226 s->zstream.next_in = s->compressed_block;
227 s->zstream.avail_in = bytes;
228 s->zstream.next_out = s->uncompressed_block;
229 s->zstream.avail_out = s->block_size;
230 ret = inflateReset(&s->zstream);
231 if (ret != Z_OK) {
232 return -1;
233 }
234 ret = inflate(&s->zstream, Z_FINISH);
235 if (ret != Z_STREAM_END || s->zstream.total_out != s->block_size) {
236 return -1;
237 }
238
239 s->current_block = block_num;
240 }
241 return 0;
242 }
243
244 static int coroutine_fn
245 cloop_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
246 QEMUIOVector *qiov, int flags)
247 {
248 BDRVCloopState *s = bs->opaque;
249 uint64_t sector_num = offset >> BDRV_SECTOR_BITS;
250 int nb_sectors = bytes >> BDRV_SECTOR_BITS;
251 int ret, i;
252
253 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
254 assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
255
256 qemu_co_mutex_lock(&s->lock);
257
258 for (i = 0; i < nb_sectors; i++) {
259 void *data;
260 uint32_t sector_offset_in_block =
261 ((sector_num + i) % s->sectors_per_block),
262 block_num = (sector_num + i) / s->sectors_per_block;
263 if (cloop_read_block(bs, block_num) != 0) {
264 ret = -EIO;
265 goto fail;
266 }
267
268 data = s->uncompressed_block + sector_offset_in_block * 512;
269 qemu_iovec_from_buf(qiov, i * 512, data, 512);
270 }
271
272 ret = 0;
273 fail:
274 qemu_co_mutex_unlock(&s->lock);
275
276 return ret;
277 }
278
279 static void cloop_close(BlockDriverState *bs)
280 {
281 BDRVCloopState *s = bs->opaque;
282 g_free(s->offsets);
283 g_free(s->compressed_block);
284 g_free(s->uncompressed_block);
285 inflateEnd(&s->zstream);
286 }
287
288 static BlockDriver bdrv_cloop = {
289 .format_name = "cloop",
290 .instance_size = sizeof(BDRVCloopState),
291 .bdrv_probe = cloop_probe,
292 .bdrv_open = cloop_open,
293 .bdrv_child_perm = bdrv_format_default_perms,
294 .bdrv_refresh_limits = cloop_refresh_limits,
295 .bdrv_co_preadv = cloop_co_preadv,
296 .bdrv_close = cloop_close,
297 };
298
299 static void bdrv_cloop_init(void)
300 {
301 bdrv_register(&bdrv_cloop);
302 }
303
304 block_init(bdrv_cloop_init);