source: mainline/uspace/srv/bd/file_bd/file_bd.c@ 49160c4

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 49160c4 was 15f3c3f, checked in by Jiri Svoboda <jiri@…>, 14 years ago

Rename devmap to loc, devfs to locfs.
  • 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(NAME ": Unable to register device '%s'.\n",
122 device_name);
123 return rc;
124 }
125
126 printf(NAME ": Accepting connections\n");
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 int rc;
142 long img_size;
143
144 rc = loc_server_register(NAME, file_bd_connection);
145 if (rc < 0) {
146 printf(NAME ": Unable to register driver.\n");
147 return rc;
148 }
149
150 img = fopen(fname, "rb+");
151 if (img == NULL)
152 return EINVAL;
153
154 if (fseek(img, 0, SEEK_END) != 0) {
155 fclose(img);
156 return EIO;
157 }
158
159 img_size = ftell(img);
160 if (img_size < 0) {
161 fclose(img);
162 return EIO;
163 }
164
165 num_blocks = img_size / block_size;
166
167 fibril_mutex_initialize(&dev_lock);
168
169 return EOK;
170}
171
172static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall, void *arg)
173{
174 void *fs_va = NULL;
175 ipc_callid_t callid;
176 ipc_call_t call;
177 sysarg_t method;
178 size_t comm_size;
179 unsigned int flags;
180 int retval;
181 uint64_t ba;
182 size_t cnt;
183
184 /* Answer the IPC_M_CONNECT_ME_TO call. */
185 async_answer_0(iid, EOK);
186
187 if (!async_share_out_receive(&callid, &comm_size, &flags)) {
188 async_answer_0(callid, EHANGUP);
189 return;
190 }
191
192 fs_va = as_get_mappable_page(comm_size);
193 if (fs_va == NULL) {
194 async_answer_0(callid, EHANGUP);
195 return;
196 }
197
198 (void) async_share_out_finalize(callid, fs_va);
199
200 while (true) {
201 callid = async_get_call(&call);
202 method = IPC_GET_IMETHOD(call);
203
204 if (!method) {
205 /* The other side has hung up. */
206 async_answer_0(callid, EOK);
207 return;
208 }
209
210 switch (method) {
211 case BD_READ_BLOCKS:
212 ba = MERGE_LOUP32(IPC_GET_ARG1(call),
213 IPC_GET_ARG2(call));
214 cnt = IPC_GET_ARG3(call);
215 if (cnt * block_size > comm_size) {
216 retval = ELIMIT;
217 break;
218 }
219 retval = file_bd_read_blocks(ba, cnt, fs_va);
220 break;
221 case BD_WRITE_BLOCKS:
222 ba = MERGE_LOUP32(IPC_GET_ARG1(call),
223 IPC_GET_ARG2(call));
224 cnt = IPC_GET_ARG3(call);
225 if (cnt * block_size > comm_size) {
226 retval = ELIMIT;
227 break;
228 }
229 retval = file_bd_write_blocks(ba, cnt, fs_va);
230 break;
231 case BD_GET_BLOCK_SIZE:
232 async_answer_1(callid, EOK, block_size);
233 continue;
234 case BD_GET_NUM_BLOCKS:
235 async_answer_2(callid, EOK, LOWER32(num_blocks),
236 UPPER32(num_blocks));
237 continue;
238 default:
239 retval = EINVAL;
240 break;
241 }
242 async_answer_0(callid, retval);
243 }
244}
245
246/** Read blocks from the device. */
247static int file_bd_read_blocks(uint64_t ba, size_t cnt, void *buf)
248{
249 size_t n_rd;
250 int rc;
251
252 /* Check whether access is within device address bounds. */
253 if (ba + cnt > num_blocks) {
254 printf(NAME ": Accessed blocks %" PRIuOFF64 "-%" PRIuOFF64 ", while "
255 "max block number is %" PRIuOFF64 ".\n", ba, ba + cnt - 1,
256 num_blocks - 1);
257 return ELIMIT;
258 }
259
260 fibril_mutex_lock(&dev_lock);
261
262 clearerr(img);
263 rc = fseek(img, ba * block_size, SEEK_SET);
264 if (rc < 0) {
265 fibril_mutex_unlock(&dev_lock);
266 return EIO;
267 }
268
269 n_rd = fread(buf, block_size, cnt, img);
270
271 if (ferror(img)) {
272 fibril_mutex_unlock(&dev_lock);
273 return EIO; /* Read error */
274 }
275
276 fibril_mutex_unlock(&dev_lock);
277
278 if (n_rd < cnt)
279 return EINVAL; /* Read beyond end of device */
280
281 return EOK;
282}
283
284/** Write blocks to the device. */
285static int file_bd_write_blocks(uint64_t ba, size_t cnt, const void *buf)
286{
287 size_t n_wr;
288 int rc;
289
290 /* Check whether access is within device address bounds. */
291 if (ba + cnt > num_blocks) {
292 printf(NAME ": Accessed blocks %" PRIuOFF64 "-%" PRIuOFF64 ", while "
293 "max block number is %" PRIuOFF64 ".\n", ba, ba + cnt - 1,
294 num_blocks - 1);
295 return ELIMIT;
296 }
297
298 fibril_mutex_lock(&dev_lock);
299
300 clearerr(img);
301 rc = fseek(img, ba * block_size, SEEK_SET);
302 if (rc < 0) {
303 fibril_mutex_unlock(&dev_lock);
304 return EIO;
305 }
306
307 n_wr = fwrite(buf, block_size, cnt, img);
308
309 if (ferror(img) || n_wr < cnt) {
310 fibril_mutex_unlock(&dev_lock);
311 return EIO; /* Write error */
312 }
313
314 if (fflush(img) != 0) {
315 fibril_mutex_unlock(&dev_lock);
316 return EIO;
317 }
318
319 fibril_mutex_unlock(&dev_lock);
320
321 return EOK;
322}
323
324/**
325 * @}
326 */
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