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