source: mainline/uspace/srv/bd/file_bd/file_bd.c@ 14c5005

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 14c5005 was faba839, checked in by Martin Decky <martin@…>, 13 years ago

use symbolic values for address space constants
  • Property mode set to 100644
File size: 7.3 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 <unistd.h>
43#include <ipc/bd.h>
44#include <async.h>
45#include <as.h>
46#include <fibril_synch.h>
47#include <loc.h>
48#include <sys/types.h>
49#include <sys/typefmt.h>
50#include <errno.h>
51#include <bool.h>
52#include <task.h>
53#include <macros.h>
54
55#define NAME "file_bd"
56
57#define DEFAULT_BLOCK_SIZE 512
58
59static size_t block_size;
60static aoff64_t num_blocks;
61static FILE *img;
62
63static service_id_t service_id;
64static fibril_mutex_t dev_lock;
65
66static void print_usage(void);
67static int file_bd_init(const char *fname);
68static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall, void *);
69static int file_bd_read_blocks(uint64_t ba, size_t cnt, void *buf);
70static int file_bd_write_blocks(uint64_t ba, size_t cnt, const void *buf);
71
72int main(int argc, char **argv)
73{
74 int rc;
75 char *image_name;
76 char *device_name;
77
78 printf(NAME ": File-backed block device driver\n");
79
80 block_size = DEFAULT_BLOCK_SIZE;
81
82 ++argv; --argc;
83 while (*argv != NULL && (*argv)[0] == '-') {
84 /* Option */
85 if (str_cmp(*argv, "-b") == 0) {
86 if (argc < 2) {
87 printf("Argument missing.\n");
88 print_usage();
89 return -1;
90 }
91
92 rc = str_size_t(argv[1], NULL, 10, true, &block_size);
93 if (rc != EOK || block_size == 0) {
94 printf("Invalid block size '%s'.\n", argv[1]);
95 print_usage();
96 return -1;
97 }
98 ++argv; --argc;
99 } else {
100 printf("Invalid option '%s'.\n", *argv);
101 print_usage();
102 return -1;
103 }
104 ++argv; --argc;
105 }
106
107 if (argc < 2) {
108 printf("Missing arguments.\n");
109 print_usage();
110 return -1;
111 }
112
113 image_name = argv[0];
114 device_name = argv[1];
115
116 if (file_bd_init(image_name) != EOK)
117 return -1;
118
119 rc = loc_service_register(device_name, &service_id);
120 if (rc != EOK) {
121 printf("%s: Unable to register device '%s'.\n",
122 NAME, device_name);
123 return rc;
124 }
125
126 printf("%s: Accepting connections\n", NAME);
127 task_retval(0);
128 async_manager();
129
130 /* Not reached */
131 return 0;
132}
133
134static void print_usage(void)
135{
136 printf("Usage: " NAME " [-b <block_size>] <image_file> <device_name>\n");
137}
138
139static int file_bd_init(const char *fname)
140{
141 async_set_client_connection(file_bd_connection);
142 int rc = loc_server_register(NAME);
143 if (rc != EOK) {
144 printf("%s: Unable to register driver.\n", NAME);
145 return rc;
146 }
147
148 img = fopen(fname, "rb+");
149 if (img == NULL)
150 return EINVAL;
151
152 if (fseek(img, 0, SEEK_END) != 0) {
153 fclose(img);
154 return EIO;
155 }
156
157 off64_t img_size = ftell(img);
158 if (img_size < 0) {
159 fclose(img);
160 return EIO;
161 }
162
163 num_blocks = img_size / block_size;
164
165 fibril_mutex_initialize(&dev_lock);
166
167 return EOK;
168}
169
170static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall, void *arg)
171{
172 void *fs_va = NULL;
173 ipc_callid_t callid;
174 ipc_call_t call;
175 sysarg_t method;
176 size_t comm_size;
177 unsigned int flags;
178 int retval;
179 uint64_t ba;
180 size_t cnt;
181
182 /* Answer the IPC_M_CONNECT_ME_TO call. */
183 async_answer_0(iid, EOK);
184
185 if (!async_share_out_receive(&callid, &comm_size, &flags)) {
186 async_answer_0(callid, EHANGUP);
187 return;
188 }
189
190 (void) async_share_out_finalize(callid, &fs_va);
191 if (fs_va == AS_MAP_FAILED) {
192 async_answer_0(callid, EHANGUP);
193 return;
194 }
195
196 while (true) {
197 callid = async_get_call(&call);
198 method = IPC_GET_IMETHOD(call);
199
200 if (!method) {
201 /* The other side has hung up. */
202 async_answer_0(callid, EOK);
203 return;
204 }
205
206 switch (method) {
207 case BD_READ_BLOCKS:
208 ba = MERGE_LOUP32(IPC_GET_ARG1(call),
209 IPC_GET_ARG2(call));
210 cnt = IPC_GET_ARG3(call);
211 if (cnt * block_size > comm_size) {
212 retval = ELIMIT;
213 break;
214 }
215 retval = file_bd_read_blocks(ba, cnt, fs_va);
216 break;
217 case BD_WRITE_BLOCKS:
218 ba = MERGE_LOUP32(IPC_GET_ARG1(call),
219 IPC_GET_ARG2(call));
220 cnt = IPC_GET_ARG3(call);
221 if (cnt * block_size > comm_size) {
222 retval = ELIMIT;
223 break;
224 }
225 retval = file_bd_write_blocks(ba, cnt, fs_va);
226 break;
227 case BD_GET_BLOCK_SIZE:
228 async_answer_1(callid, EOK, block_size);
229 continue;
230 case BD_GET_NUM_BLOCKS:
231 async_answer_2(callid, EOK, LOWER32(num_blocks),
232 UPPER32(num_blocks));
233 continue;
234 default:
235 retval = EINVAL;
236 break;
237 }
238 async_answer_0(callid, retval);
239 }
240}
241
242/** Read blocks from the device. */
243static int file_bd_read_blocks(uint64_t ba, size_t cnt, void *buf)
244{
245 size_t n_rd;
246 int rc;
247
248 /* Check whether access is within device address bounds. */
249 if (ba + cnt > num_blocks) {
250 printf(NAME ": Accessed blocks %" PRIuOFF64 "-%" PRIuOFF64 ", while "
251 "max block number is %" PRIuOFF64 ".\n", ba, ba + cnt - 1,
252 num_blocks - 1);
253 return ELIMIT;
254 }
255
256 fibril_mutex_lock(&dev_lock);
257
258 clearerr(img);
259 rc = fseek(img, ba * block_size, SEEK_SET);
260 if (rc < 0) {
261 fibril_mutex_unlock(&dev_lock);
262 return EIO;
263 }
264
265 n_rd = fread(buf, block_size, cnt, img);
266
267 if (ferror(img)) {
268 fibril_mutex_unlock(&dev_lock);
269 return EIO; /* Read error */
270 }
271
272 fibril_mutex_unlock(&dev_lock);
273
274 if (n_rd < cnt)
275 return EINVAL; /* Read beyond end of device */
276
277 return EOK;
278}
279
280/** Write blocks to the device. */
281static int file_bd_write_blocks(uint64_t ba, size_t cnt, const void *buf)
282{
283 size_t n_wr;
284 int rc;
285
286 /* Check whether access is within device address bounds. */
287 if (ba + cnt > num_blocks) {
288 printf(NAME ": Accessed blocks %" PRIuOFF64 "-%" PRIuOFF64 ", while "
289 "max block number is %" PRIuOFF64 ".\n", ba, ba + cnt - 1,
290 num_blocks - 1);
291 return ELIMIT;
292 }
293
294 fibril_mutex_lock(&dev_lock);
295
296 clearerr(img);
297 rc = fseek(img, ba * block_size, SEEK_SET);
298 if (rc < 0) {
299 fibril_mutex_unlock(&dev_lock);
300 return EIO;
301 }
302
303 n_wr = fwrite(buf, block_size, cnt, img);
304
305 if (ferror(img) || n_wr < cnt) {
306 fibril_mutex_unlock(&dev_lock);
307 return EIO; /* Write error */
308 }
309
310 if (fflush(img) != 0) {
311 fibril_mutex_unlock(&dev_lock);
312 return EIO;
313 }
314
315 fibril_mutex_unlock(&dev_lock);
316
317 return EOK;
318}
319
320/**
321 * @}
322 */
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