uspace/srv/bd/file_bd/file_bd.c

   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 <sys/types.h>
  48 #include <sys/typefmt.h>
  49 #include <errno.h>
  50 #include <stdbool.h>
  51 #include <task.h>
  52 #include <macros.h>
  53
  54 #define NAME "file_bd"
  55
  56 #define DEFAULT_BLOCK_SIZE 512
  57
  58 static size_t block_size;
  59 static aoff64_t num_blocks;
  60 static FILE *img;
  61
  62 static service_id_t service_id;
  63 static bd_srvs_t bd_srvs;
  64 static fibril_mutex_t dev_lock;
  65
  66 static void print_usage(void);
  67 static int file_bd_init(const char *fname);
  68 static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall, void *);
  69
  70 static int file_bd_open(bd_srvs_t *, bd_srv_t *);
  71 static int file_bd_close(bd_srv_t *);
  72 static int file_bd_read_blocks(bd_srv_t *, aoff64_t, size_t, void *, size_t);
  73 static int file_bd_write_blocks(bd_srv_t *, aoff64_t, size_t, const void *, size_t);
  74 static int file_bd_get_block_size(bd_srv_t *, size_t *);
  75 static int file_bd_get_num_blocks(bd_srv_t *, aoff64_t *);
  76
  77 static bd_ops_t file_bd_ops = {
  78         .open = file_bd_open,
  79         .close = file_bd_close,
  80         .read_blocks = file_bd_read_blocks,
  81         .write_blocks = file_bd_write_blocks,
  82         .get_block_size = file_bd_get_block_size,
  83         .get_num_blocks = file_bd_get_num_blocks
  84 };
  85
  86 int main(int argc, char **argv)
  87 {
  88         int rc;
  89         char *image_name;
  90         char *device_name;
  91         category_id_t disk_cat;
  92
  93         printf(NAME ": File-backed block device driver\n");
  94
  95         block_size = DEFAULT_BLOCK_SIZE;
  96
  97         ++argv; --argc;
  98         while (*argv != NULL && (*argv)[0] == '-') {
  99                 /* Option */
 100                 if (str_cmp(*argv, "-b") == 0) {
 101                         if (argc < 2) {
 102                                 printf("Argument missing.\n");
 103                                 print_usage();
 104                                 return -1;
 105                         }
 106
 107                         rc = str_size_t(argv[1], NULL, 10, true, &block_size);
 108                         if (rc != EOK || block_size == 0) {
 109                                 printf("Invalid block size '%s'.\n", argv[1]);
 110                                 print_usage();
 111                                 return -1;
 112                         }
 113                         ++argv; --argc;
 114                 } else {
 115                         printf("Invalid option '%s'.\n", *argv);
 116                         print_usage();
 117                         return -1;
 118                 }
 119                 ++argv; --argc;
 120         }
 121
 122         if (argc < 2) {
 123                 printf("Missing arguments.\n");
 124                 print_usage();
 125                 return -1;
 126         }
 127
 128         image_name = argv[0];
 129         device_name = argv[1];
 130
 131         if (file_bd_init(image_name) != EOK)
 132                 return -1;
 133
 134         rc = loc_service_register(device_name, &service_id);
 135         if (rc != EOK) {
 136                 printf("%s: Unable to register device '%s'.\n",
 137                     NAME, device_name);
 138                 return rc;
 139         }
 140
 141         rc = loc_category_get_id("disk", &disk_cat, IPC_FLAG_BLOCKING);
 142         if (rc != EOK) {
 143                 printf("%s: Failed resolving category 'disk'.\n", NAME);
 144                 return rc;
 145         }
 146
 147         rc = loc_service_add_to_cat(service_id, disk_cat);
 148         if (rc != EOK) {
 149                 printf("%s: Failed adding %s to category.",
 150                     NAME, device_name);
 151                 return rc;
 152         }
 153
 154         printf("%s: Accepting connections\n", NAME);
 155         task_retval(0);
 156         async_manager();
 157
 158         /* Not reached */
 159         return 0;
 160 }
 161
 162 static void print_usage(void)
 163 {
 164         printf("Usage: " NAME " [-b <block_size>] <image_file> <device_name>\n");
 165 }
 166
 167 static int file_bd_init(const char *fname)
 168 {
 169         bd_srvs_init(&bd_srvs);
 170         bd_srvs.ops = &file_bd_ops;
 171
 172         async_set_fallback_port_handler(file_bd_connection, NULL);
 173         int rc = loc_server_register(NAME);
 174         if (rc != EOK) {
 175                 printf("%s: Unable to register driver.\n", NAME);
 176                 return rc;
 177         }
 178
 179         img = fopen(fname, "rb+");
 180         if (img == NULL)
 181                 return EINVAL;
 182
 183         if (fseek(img, 0, SEEK_END) != 0) {
 184                 fclose(img);
 185                 return EIO;
 186         }
 187
 188         off64_t img_size = ftell(img);
 189         if (img_size < 0) {
 190                 fclose(img);
 191                 return EIO;
 192         }
 193
 194         num_blocks = img_size / block_size;
 195
 196         fibril_mutex_initialize(&dev_lock);
 197
 198         return EOK;
 199 }
 200
 201 static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall, void *arg)
 202 {
 203         bd_conn(iid, icall, &bd_srvs);
 204 }
 205
 206 /** Open device. */
 207 static int file_bd_open(bd_srvs_t *bds, bd_srv_t *bd)
 208 {
 209         return EOK;
 210 }
 211
 212 /** Close device. */
 213 static int file_bd_close(bd_srv_t *bd)
 214 {
 215         return EOK;
 216 }
 217
 218 /** Read blocks from the device. */
 219 static int file_bd_read_blocks(bd_srv_t *bd, uint64_t ba, size_t cnt, void *buf,
 220     size_t size)
 221 {
 222         size_t n_rd;
 223         int rc;
 224
 225         if (size < cnt * block_size)
 226                 return EINVAL;
 227
 228         /* Check whether access is within device address bounds. */
 229         if (ba + cnt > num_blocks) {
 230                 printf(NAME ": Accessed blocks %" PRIuOFF64 "-%" PRIuOFF64 ", while "
 231                     "max block number is %" PRIuOFF64 ".\n", ba, ba + cnt - 1,
 232                     num_blocks - 1);
 233                 return ELIMIT;
 234         }
 235
 236         fibril_mutex_lock(&dev_lock);
 237
 238         clearerr(img);
 239         rc = fseek(img, ba * block_size, SEEK_SET);
 240         if (rc < 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. */
 261 static int 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         int rc;
 266
 267         if (size < cnt * block_size)
 268                 return EINVAL;
 269
 270         /* Check whether access is within device address bounds. */
 271         if (ba + cnt > num_blocks) {
 272                 printf(NAME ": Accessed blocks %" PRIuOFF64 "-%" PRIuOFF64 ", while "
 273                     "max block number is %" PRIuOFF64 ".\n", ba, ba + cnt - 1,
 274                     num_blocks - 1);
 275                 return ELIMIT;
 276         }
 277
 278         fibril_mutex_lock(&dev_lock);
 279
 280         clearerr(img);
 281         rc = fseek(img, ba * block_size, SEEK_SET);
 282         if (rc < 0) {
 283                 fibril_mutex_unlock(&dev_lock);
 284                 return EIO;
 285         }
 286
 287         n_wr = fwrite(buf, block_size, cnt, img);
 288
 289         if (ferror(img) || n_wr < cnt) {
 290                 fibril_mutex_unlock(&dev_lock);
 291                 return EIO;     /* Write error */
 292         }
 293
 294         if (fflush(img) != 0) {
 295                 fibril_mutex_unlock(&dev_lock);
 296                 return EIO;
 297         }
 298
 299         fibril_mutex_unlock(&dev_lock);
 300
 301         return EOK;
 302 }
 303
 304 /** Get device block size. */
 305 static int file_bd_get_block_size(bd_srv_t *bd, size_t *rsize)
 306 {
 307         *rsize = block_size;
 308         return EOK;
 309 }
 310
 311 /** Get number of blocks on device. */
 312 static int file_bd_get_num_blocks(bd_srv_t *bd, aoff64_t *rnb)
 313 {
 314         *rnb = num_blocks;
 315         return EOK;
 316 }
 317
 318 /**
 319  * @}
 320  */