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/error-report.h"
27 #include "block/block-io.h"
28 #include "block/block_int.h"
29 #include "qemu/module.h"
30 #include "qemu/bswap.h"
31 #include <zlib.h>
32
33 /* Maximum compressed block size */
34 #define MAX_BLOCK_SIZE (64 * 1024 * 1024)
35
36 typedef struct BDRVCloopState {
37 CoMutex lock;
38 uint32_t block_size;
39 uint32_t n_blocks;
40 uint64_t *offsets;
41 uint32_t sectors_per_block;
42 uint32_t current_block;
43 uint8_t *compressed_block;
44 uint8_t *uncompressed_block;
45 z_stream zstream;
46 } BDRVCloopState;
47
cloop_probe(const uint8_t * buf,int buf_size,const char * filename)48 static int cloop_probe(const uint8_t *buf, int buf_size, const char *filename)
49 {
50 const char *magic_version_2_0 = "#!/bin/sh\n"
51 "#V2.0 Format\n"
52 "modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n";
53 int length = strlen(magic_version_2_0);
54 if (length > buf_size) {
55 length = buf_size;
56 }
57 if (!memcmp(magic_version_2_0, buf, length)) {
58 return 2;
59 }
60 return 0;
61 }
62
cloop_open(BlockDriverState * bs,QDict * options,int flags,Error ** errp)63 static int cloop_open(BlockDriverState *bs, QDict *options, int flags,
64 Error **errp)
65 {
66 BDRVCloopState *s = bs->opaque;
67 uint32_t offsets_size, max_compressed_block_size = 1, i;
68 int ret;
69
70 GLOBAL_STATE_CODE();
71
72 bdrv_graph_rdlock_main_loop();
73 ret = bdrv_apply_auto_read_only(bs, NULL, errp);
74 bdrv_graph_rdunlock_main_loop();
75 if (ret < 0) {
76 return ret;
77 }
78
79 ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
80 if (ret < 0) {
81 return ret;
82 }
83
84 GRAPH_RDLOCK_GUARD_MAINLOOP();
85
86 /* read header */
87 ret = bdrv_pread(bs->file, 128, 4, &s->block_size, 0);
88 if (ret < 0) {
89 return ret;
90 }
91 s->block_size = be32_to_cpu(s->block_size);
92 if (s->block_size % 512) {
93 error_setg(errp, "block_size %" PRIu32 " must be a multiple of 512",
94 s->block_size);
95 return -EINVAL;
96 }
97 if (s->block_size == 0) {
98 error_setg(errp, "block_size cannot be zero");
99 return -EINVAL;
100 }
101
102 /* cloop's create_compressed_fs.c warns about block sizes beyond 256 KB but
103 * we can accept more. Prevent ridiculous values like 4 GB - 1 since we
104 * need a buffer this big.
105 */
106 if (s->block_size > MAX_BLOCK_SIZE) {
107 error_setg(errp, "block_size %" PRIu32 " must be %u MB or less",
108 s->block_size,
109 MAX_BLOCK_SIZE / (1024 * 1024));
110 return -EINVAL;
111 }
112
113 ret = bdrv_pread(bs->file, 128 + 4, 4, &s->n_blocks, 0);
114 if (ret < 0) {
115 return ret;
116 }
117 s->n_blocks = be32_to_cpu(s->n_blocks);
118
119 /* read offsets */
120 if (s->n_blocks > (UINT32_MAX - 1) / sizeof(uint64_t)) {
121 /* Prevent integer overflow */
122 error_setg(errp, "n_blocks %" PRIu32 " must be %zu or less",
123 s->n_blocks,
124 (UINT32_MAX - 1) / sizeof(uint64_t));
125 return -EINVAL;
126 }
127 offsets_size = (s->n_blocks + 1) * sizeof(uint64_t);
128 if (offsets_size > 512 * 1024 * 1024) {
129 /* Prevent ridiculous offsets_size which causes memory allocation to
130 * fail or overflows bdrv_pread() size. In practice the 512 MB
131 * offsets[] limit supports 16 TB images at 256 KB block size.
132 */
133 error_setg(errp, "image requires too many offsets, "
134 "try increasing block size");
135 return -EINVAL;
136 }
137
138 s->offsets = g_try_malloc(offsets_size);
139 if (s->offsets == NULL) {
140 error_setg(errp, "Could not allocate offsets table");
141 return -ENOMEM;
142 }
143
144 ret = bdrv_pread(bs->file, 128 + 4 + 4, offsets_size, s->offsets, 0);
145 if (ret < 0) {
146 goto fail;
147 }
148
149 for (i = 0; i < s->n_blocks + 1; i++) {
150 uint64_t size;
151
152 s->offsets[i] = be64_to_cpu(s->offsets[i]);
153 if (i == 0) {
154 continue;
155 }
156
157 if (s->offsets[i] < s->offsets[i - 1]) {
158 error_setg(errp, "offsets not monotonically increasing at "
159 "index %" PRIu32 ", image file is corrupt", i);
160 ret = -EINVAL;
161 goto fail;
162 }
163
164 size = s->offsets[i] - s->offsets[i - 1];
165
166 /* Compressed blocks should be smaller than the uncompressed block size
167 * but maybe compression performed poorly so the compressed block is
168 * actually bigger. Clamp down on unrealistic values to prevent
169 * ridiculous s->compressed_block allocation.
170 */
171 if (size > 2 * MAX_BLOCK_SIZE) {
172 error_setg(errp, "invalid compressed block size at index %" PRIu32
173 ", image file is corrupt", i);
174 ret = -EINVAL;
175 goto fail;
176 }
177
178 if (size > max_compressed_block_size) {
179 max_compressed_block_size = size;
180 }
181 }
182
183 /* initialize zlib engine */
184 s->compressed_block = g_try_malloc(max_compressed_block_size + 1);
185 if (s->compressed_block == NULL) {
186 error_setg(errp, "Could not allocate compressed_block");
187 ret = -ENOMEM;
188 goto fail;
189 }
190
191 s->uncompressed_block = g_try_malloc(s->block_size);
192 if (s->uncompressed_block == NULL) {
193 error_setg(errp, "Could not allocate uncompressed_block");
194 ret = -ENOMEM;
195 goto fail;
196 }
197
198 if (inflateInit(&s->zstream) != Z_OK) {
199 ret = -EINVAL;
200 goto fail;
201 }
202 s->current_block = s->n_blocks;
203
204 s->sectors_per_block = s->block_size/512;
205 bs->total_sectors = s->n_blocks * s->sectors_per_block;
206 qemu_co_mutex_init(&s->lock);
207 return 0;
208
209 fail:
210 g_free(s->offsets);
211 g_free(s->compressed_block);
212 g_free(s->uncompressed_block);
213 return ret;
214 }
215
cloop_refresh_limits(BlockDriverState * bs,Error ** errp)216 static void cloop_refresh_limits(BlockDriverState *bs, Error **errp)
217 {
218 bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */
219 }
220
221 static int coroutine_fn GRAPH_RDLOCK
cloop_read_block(BlockDriverState * bs,int block_num)222 cloop_read_block(BlockDriverState *bs, int block_num)
223 {
224 BDRVCloopState *s = bs->opaque;
225
226 if (s->current_block != block_num) {
227 int ret;
228 uint32_t bytes = s->offsets[block_num + 1] - s->offsets[block_num];
229
230 ret = bdrv_co_pread(bs->file, s->offsets[block_num], bytes,
231 s->compressed_block, 0);
232 if (ret < 0) {
233 return -1;
234 }
235
236 s->zstream.next_in = s->compressed_block;
237 s->zstream.avail_in = bytes;
238 s->zstream.next_out = s->uncompressed_block;
239 s->zstream.avail_out = s->block_size;
240 ret = inflateReset(&s->zstream);
241 if (ret != Z_OK) {
242 return -1;
243 }
244 ret = inflate(&s->zstream, Z_FINISH);
245 if (ret != Z_STREAM_END || s->zstream.total_out != s->block_size) {
246 return -1;
247 }
248
249 s->current_block = block_num;
250 }
251 return 0;
252 }
253
254 static int coroutine_fn GRAPH_RDLOCK
cloop_co_preadv(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,BdrvRequestFlags flags)255 cloop_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
256 QEMUIOVector *qiov, BdrvRequestFlags flags)
257 {
258 BDRVCloopState *s = bs->opaque;
259 uint64_t sector_num = offset >> BDRV_SECTOR_BITS;
260 int nb_sectors = bytes >> BDRV_SECTOR_BITS;
261 int ret, i;
262
263 assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
264 assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));
265
266 qemu_co_mutex_lock(&s->lock);
267
268 for (i = 0; i < nb_sectors; i++) {
269 void *data;
270 uint32_t sector_offset_in_block =
271 ((sector_num + i) % s->sectors_per_block),
272 block_num = (sector_num + i) / s->sectors_per_block;
273 if (cloop_read_block(bs, block_num) != 0) {
274 ret = -EIO;
275 goto fail;
276 }
277
278 data = s->uncompressed_block + sector_offset_in_block * 512;
279 qemu_iovec_from_buf(qiov, i * 512, data, 512);
280 }
281
282 ret = 0;
283 fail:
284 qemu_co_mutex_unlock(&s->lock);
285
286 return ret;
287 }
288
cloop_close(BlockDriverState * bs)289 static void cloop_close(BlockDriverState *bs)
290 {
291 BDRVCloopState *s = bs->opaque;
292 g_free(s->offsets);
293 g_free(s->compressed_block);
294 g_free(s->uncompressed_block);
295 inflateEnd(&s->zstream);
296 }
297
298 static BlockDriver bdrv_cloop = {
299 .format_name = "cloop",
300 .instance_size = sizeof(BDRVCloopState),
301 .bdrv_probe = cloop_probe,
302 .bdrv_open = cloop_open,
303 .bdrv_child_perm = bdrv_default_perms,
304 .bdrv_refresh_limits = cloop_refresh_limits,
305 .bdrv_co_preadv = cloop_co_preadv,
306 .bdrv_close = cloop_close,
307 .is_format = true,
308 };
309
bdrv_cloop_init(void)310 static void bdrv_cloop_init(void)
311 {
312 bdrv_register(&bdrv_cloop);
313 }
314
315 block_init(bdrv_cloop_init);
316