source: mainline/uspace/srv/bd/file_bd/file_bd.c@ 1f383dde

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 1f383dde was 228e490, checked in by Martin Decky <martin@…>, 15 years ago

initial modifications for supporting declarative IPC interfaces
  • 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/ipc.h>
44#include <ipc/bd.h>
45#include <async.h>
46#include <as.h>
47#include <fibril_synch.h>
48#include <devmap.h>
49#include <sys/types.h>
50#include <sys/typefmt.h>
51#include <errno.h>
52#include <bool.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 devmap_handle_t devmap_handle;
65static fibril_mutex_t dev_lock;
66
67static void print_usage(void);
68static int file_bd_init(const char *fname);
69static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall);
70static int file_bd_read_blocks(uint64_t ba, size_t cnt, void *buf);
71static int file_bd_write_blocks(uint64_t ba, size_t cnt, const void *buf);
72
73int main(int argc, char **argv)
74{
75 int rc;
76 char *image_name;
77 char *device_name;
78
79 printf(NAME ": File-backed block device driver\n");
80
81 block_size = DEFAULT_BLOCK_SIZE;
82
83 ++argv; --argc;
84 while (*argv != NULL && (*argv)[0] == '-') {
85 /* Option */
86 if (str_cmp(*argv, "-b") == 0) {
87 if (argc < 2) {
88 printf("Argument missing.\n");
89 print_usage();
90 return -1;
91 }
92
93 rc = str_size_t(argv[1], NULL, 10, true, &block_size);
94 if (rc != EOK || block_size == 0) {
95 printf("Invalid block size '%s'.\n", argv[1]);
96 print_usage();
97 return -1;
98 }
99 ++argv; --argc;
100 } else {
101 printf("Invalid option '%s'.\n", *argv);
102 print_usage();
103 return -1;
104 }
105 ++argv; --argc;
106 }
107
108 if (argc < 2) {
109 printf("Missing arguments.\n");
110 print_usage();
111 return -1;
112 }
113
114 image_name = argv[0];
115 device_name = argv[1];
116
117 if (file_bd_init(image_name) != EOK)
118 return -1;
119
120 rc = devmap_device_register(device_name, &devmap_handle);
121 if (rc != EOK) {
122 devmap_hangup_phone(DEVMAP_DRIVER);
123 printf(NAME ": Unable to register device '%s'.\n",
124 device_name);
125 return rc;
126 }
127
128 printf(NAME ": Accepting connections\n");
129 task_retval(0);
130 async_manager();
131
132 /* Not reached */
133 return 0;
134}
135
136static void print_usage(void)
137{
138 printf("Usage: " NAME " [-b <block_size>] <image_file> <device_name>\n");
139}
140
141static int file_bd_init(const char *fname)
142{
143 int rc;
144 long img_size;
145
146 rc = devmap_driver_register(NAME, file_bd_connection);
147 if (rc < 0) {
148 printf(NAME ": Unable to register driver.\n");
149 return rc;
150 }
151
152 img = fopen(fname, "rb+");
153 if (img == NULL)
154 return EINVAL;
155
156 if (fseek(img, 0, SEEK_END) != 0) {
157 fclose(img);
158 return EIO;
159 }
160
161 img_size = ftell(img);
162 if (img_size < 0) {
163 fclose(img);
164 return EIO;
165 }
166
167 num_blocks = img_size / block_size;
168
169 fibril_mutex_initialize(&dev_lock);
170
171 return EOK;
172}
173
174static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall)
175{
176 void *fs_va = NULL;
177 ipc_callid_t callid;
178 ipc_call_t call;
179 sysarg_t method;
180 size_t comm_size;
181 int flags;
182 int retval;
183 uint64_t ba;
184 size_t cnt;
185
186 /* Answer the IPC_M_CONNECT_ME_TO call. */
187 ipc_answer_0(iid, EOK);
188
189 if (!async_share_out_receive(&callid, &comm_size, &flags)) {
190 ipc_answer_0(callid, EHANGUP);
191 return;
192 }
193
194 fs_va = as_get_mappable_page(comm_size);
195 if (fs_va == NULL) {
196 ipc_answer_0(callid, EHANGUP);
197 return;
198 }
199
200 (void) async_share_out_finalize(callid, fs_va);
201
202 while (1) {
203 callid = async_get_call(&call);
204 method = IPC_GET_IMETHOD(call);
205 switch (method) {
206 case IPC_M_PHONE_HUNGUP:
207 /* The other side has hung up. */
208 ipc_answer_0(callid, EOK);
209 return;
210 case BD_READ_BLOCKS:
211 ba = MERGE_LOUP32(IPC_GET_ARG1(call),
212 IPC_GET_ARG2(call));
213 cnt = IPC_GET_ARG3(call);
214 if (cnt * block_size > comm_size) {
215 retval = ELIMIT;
216 break;
217 }
218 retval = file_bd_read_blocks(ba, cnt, fs_va);
219 break;
220 case BD_WRITE_BLOCKS:
221 ba = MERGE_LOUP32(IPC_GET_ARG1(call),
222 IPC_GET_ARG2(call));
223 cnt = IPC_GET_ARG3(call);
224 if (cnt * block_size > comm_size) {
225 retval = ELIMIT;
226 break;
227 }
228 retval = file_bd_write_blocks(ba, cnt, fs_va);
229 break;
230 case BD_GET_BLOCK_SIZE:
231 ipc_answer_1(callid, EOK, block_size);
232 continue;
233 case BD_GET_NUM_BLOCKS:
234 ipc_answer_2(callid, EOK, LOWER32(num_blocks),
235 UPPER32(num_blocks));
236 continue;
237 default:
238 retval = EINVAL;
239 break;
240 }
241 ipc_answer_0(callid, retval);
242 }
243}
244
245/** Read blocks from the device. */
246static int file_bd_read_blocks(uint64_t ba, size_t cnt, void *buf)
247{
248 size_t n_rd;
249 int rc;
250
251 /* Check whether access is within device address bounds. */
252 if (ba + cnt > num_blocks) {
253 printf(NAME ": Accessed blocks %" PRIuOFF64 "-%" PRIuOFF64 ", while "
254 "max block number is %" PRIuOFF64 ".\n", ba, ba + cnt - 1,
255 num_blocks - 1);
256 return ELIMIT;
257 }
258
259 fibril_mutex_lock(&dev_lock);
260
261 clearerr(img);
262 rc = fseek(img, ba * block_size, SEEK_SET);
263 if (rc < 0) {
264 fibril_mutex_unlock(&dev_lock);
265 return EIO;
266 }
267
268 n_rd = fread(buf, block_size, cnt, img);
269
270 if (ferror(img)) {
271 fibril_mutex_unlock(&dev_lock);
272 return EIO; /* Read error */
273 }
274
275 fibril_mutex_unlock(&dev_lock);
276
277 if (n_rd < cnt)
278 return EINVAL; /* Read beyond end of device */
279
280 return EOK;
281}
282
283/** Write blocks to the device. */
284static int file_bd_write_blocks(uint64_t ba, size_t cnt, const void *buf)
285{
286 size_t n_wr;
287 int rc;
288
289 /* Check whether access is within device address bounds. */
290 if (ba + cnt > num_blocks) {
291 printf(NAME ": Accessed blocks %" PRIuOFF64 "-%" PRIuOFF64 ", while "
292 "max block number is %" PRIuOFF64 ".\n", ba, ba + cnt - 1,
293 num_blocks - 1);
294 return ELIMIT;
295 }
296
297 fibril_mutex_lock(&dev_lock);
298
299 clearerr(img);
300 rc = fseek(img, ba * block_size, SEEK_SET);
301 if (rc < 0) {
302 fibril_mutex_unlock(&dev_lock);
303 return EIO;
304 }
305
306 n_wr = fwrite(buf, block_size, cnt, img);
307
308 if (ferror(img) || n_wr < cnt) {
309 fibril_mutex_unlock(&dev_lock);
310 return EIO; /* Write error */
311 }
312
313 if (fflush(img) != 0) {
314 fibril_mutex_unlock(&dev_lock);
315 return EIO;
316 }
317
318 fibril_mutex_unlock(&dev_lock);
319
320 return EOK;
321}
322
323/**
324 * @}
325 */
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