source: mainline/uspace/srv/bd/file_bd/file_bd.c@ 3b47db6

Last change on this file since 3b47db6 was 3b47db6, checked in by Jiří Zárevúcky <zarevucky.jiri@…>, 7 years ago

(optional) Remove EXIT_RC().
  • Property mode set to 100644
File size: 7.4 KB
Line 
1/*
2 * Copyright (c) 2009 Jiri Svoboda
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup bd
30 * @{
31 */
32
33/**
34 * @file
35 * @brief File-backed block device driver
36 *
37 * Allows accessing a file as a block device. Useful for, e.g., mounting
38 * a disk image.
39 */
40
41#include <stdio.h>
42#include <async.h>
43#include <as.h>
44#include <bd_srv.h>
45#include <fibril_synch.h>
46#include <loc.h>
47#include <stddef.h>
48#include <stdint.h>
49#include <stdlib.h>
50#include <errno.h>
51#include <str_error.h>
52#include <stdbool.h>
53#include <task.h>
54#include <macros.h>
55
56#define NAME "file_bd"
57
58#define DEFAULT_BLOCK_SIZE 512
59
60static size_t block_size;
61static aoff64_t num_blocks;
62static FILE *img;
63
64static service_id_t service_id;
65static bd_srvs_t bd_srvs;
66static fibril_mutex_t dev_lock;
67
68static void print_usage(void);
69static errno_t file_bd_init(const char *fname);
70static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall, void *);
71
72static errno_t file_bd_open(bd_srvs_t *, bd_srv_t *);
73static errno_t file_bd_close(bd_srv_t *);
74static errno_t file_bd_read_blocks(bd_srv_t *, aoff64_t, size_t, void *, size_t);
75static errno_t file_bd_write_blocks(bd_srv_t *, aoff64_t, size_t, const void *, size_t);
76static errno_t file_bd_get_block_size(bd_srv_t *, size_t *);
77static errno_t file_bd_get_num_blocks(bd_srv_t *, aoff64_t *);
78
79static bd_ops_t file_bd_ops = {
80 .open = file_bd_open,
81 .close = file_bd_close,
82 .read_blocks = file_bd_read_blocks,
83 .write_blocks = file_bd_write_blocks,
84 .get_block_size = file_bd_get_block_size,
85 .get_num_blocks = file_bd_get_num_blocks
86};
87
88int main(int argc, char **argv)
89{
90 errno_t rc;
91 char *image_name;
92 char *device_name;
93 category_id_t disk_cat;
94
95 printf(NAME ": File-backed block device driver\n");
96
97 block_size = DEFAULT_BLOCK_SIZE;
98
99 ++argv; --argc;
100 while (*argv != NULL && (*argv)[0] == '-') {
101 /* Option */
102 if (str_cmp(*argv, "-b") == 0) {
103 if (argc < 2) {
104 printf("Argument missing.\n");
105 print_usage();
106 return -1;
107 }
108
109 rc = str_size_t(argv[1], NULL, 10, true, &block_size);
110 if (rc != EOK || block_size == 0) {
111 printf("Invalid block size '%s'.\n", argv[1]);
112 print_usage();
113 return -1;
114 }
115 ++argv; --argc;
116 } else {
117 printf("Invalid option '%s'.\n", *argv);
118 print_usage();
119 return -1;
120 }
121 ++argv; --argc;
122 }
123
124 if (argc < 2) {
125 printf("Missing arguments.\n");
126 print_usage();
127 return -1;
128 }
129
130 image_name = argv[0];
131 device_name = argv[1];
132
133 if (file_bd_init(image_name) != EOK)
134 return -1;
135
136 rc = loc_service_register(device_name, &service_id);
137 if (rc != EOK) {
138 printf("%s: Unable to register device '%s': %s.\n",
139 NAME, device_name, str_error(rc));
140 return rc;
141 }
142
143 rc = loc_category_get_id("disk", &disk_cat, IPC_FLAG_BLOCKING);
144 if (rc != EOK) {
145 printf("%s: Failed resolving category 'disk': %s\n", NAME, str_error(rc));
146 return rc;
147 }
148
149 rc = loc_service_add_to_cat(service_id, disk_cat);
150 if (rc != EOK) {
151 printf("%s: Failed adding %s to category: %s",
152 NAME, device_name, str_error(rc));
153 return rc;
154 }
155
156 printf("%s: Accepting connections\n", NAME);
157 task_retval(0);
158 async_manager();
159
160 /* Not reached */
161 return 0;
162}
163
164static void print_usage(void)
165{
166 printf("Usage: " NAME " [-b <block_size>] <image_file> <device_name>\n");
167}
168
169static errno_t file_bd_init(const char *fname)
170{
171 bd_srvs_init(&bd_srvs);
172 bd_srvs.ops = &file_bd_ops;
173
174 async_set_fallback_port_handler(file_bd_connection, NULL);
175 errno_t rc = loc_server_register(NAME);
176 if (rc != EOK) {
177 printf("%s: Unable to register driver.\n", NAME);
178 return rc;
179 }
180
181 img = fopen(fname, "rb+");
182 if (img == NULL)
183 return EINVAL;
184
185 if (fseek(img, 0, SEEK_END) != 0) {
186 fclose(img);
187 return EIO;
188 }
189
190 off64_t img_size = ftell(img);
191 if (img_size < 0) {
192 fclose(img);
193 return EIO;
194 }
195
196 num_blocks = img_size / block_size;
197
198 fibril_mutex_initialize(&dev_lock);
199
200 return EOK;
201}
202
203static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall, void *arg)
204{
205 bd_conn(iid, icall, &bd_srvs);
206}
207
208/** Open device. */
209static errno_t file_bd_open(bd_srvs_t *bds, bd_srv_t *bd)
210{
211 return EOK;
212}
213
214/** Close device. */
215static errno_t file_bd_close(bd_srv_t *bd)
216{
217 return EOK;
218}
219
220/** Read blocks from the device. */
221static errno_t file_bd_read_blocks(bd_srv_t *bd, uint64_t ba, size_t cnt, void *buf,
222 size_t size)
223{
224 size_t n_rd;
225
226 if (size < cnt * block_size)
227 return EINVAL;
228
229 /* Check whether access is within device address bounds. */
230 if (ba + cnt > num_blocks) {
231 printf(NAME ": Accessed blocks %" PRIuOFF64 "-%" PRIuOFF64 ", while "
232 "max block number is %" PRIuOFF64 ".\n", ba, ba + cnt - 1,
233 num_blocks - 1);
234 return ELIMIT;
235 }
236
237 fibril_mutex_lock(&dev_lock);
238
239 clearerr(img);
240 if (fseek(img, ba * block_size, SEEK_SET) < 0) {
241 fibril_mutex_unlock(&dev_lock);
242 return EIO;
243 }
244
245 n_rd = fread(buf, block_size, cnt, img);
246
247 if (ferror(img)) {
248 fibril_mutex_unlock(&dev_lock);
249 return EIO; /* Read error */
250 }
251
252 fibril_mutex_unlock(&dev_lock);
253
254 if (n_rd < cnt)
255 return EINVAL; /* Read beyond end of device */
256
257 return EOK;
258}
259
260/** Write blocks to the device. */
261static errno_t file_bd_write_blocks(bd_srv_t *bd, uint64_t ba, size_t cnt,
262 const void *buf, size_t size)
263{
264 size_t n_wr;
265
266 if (size < cnt * block_size)
267 return EINVAL;
268
269 /* Check whether access is within device address bounds. */
270 if (ba + cnt > num_blocks) {
271 printf(NAME ": Accessed blocks %" PRIuOFF64 "-%" PRIuOFF64 ", while "
272 "max block number is %" PRIuOFF64 ".\n", ba, ba + cnt - 1,
273 num_blocks - 1);
274 return ELIMIT;
275 }
276
277 fibril_mutex_lock(&dev_lock);
278
279 clearerr(img);
280 if (fseek(img, ba * block_size, SEEK_SET) < 0) {
281 fibril_mutex_unlock(&dev_lock);
282 return EIO;
283 }
284
285 n_wr = fwrite(buf, block_size, cnt, img);
286
287 if (ferror(img) || n_wr < cnt) {
288 fibril_mutex_unlock(&dev_lock);
289 return EIO; /* Write error */
290 }
291
292 if (fflush(img) != 0) {
293 fibril_mutex_unlock(&dev_lock);
294 return EIO;
295 }
296
297 fibril_mutex_unlock(&dev_lock);
298
299 return EOK;
300}
301
302/** Get device block size. */
303static errno_t file_bd_get_block_size(bd_srv_t *bd, size_t *rsize)
304{
305 *rsize = block_size;
306 return EOK;
307}
308
309/** Get number of blocks on device. */
310static errno_t file_bd_get_num_blocks(bd_srv_t *bd, aoff64_t *rnb)
311{
312 *rnb = num_blocks;
313 return EOK;
314}
315
316/**
317 * @}
318 */
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