1 /** 2 * unix_io.c - Unix style disk io functions. Originated from the Linux-NTFS project. 3 * 4 * Copyright (c) 2000-2006 Anton Altaparmakov 5 * 6 * This program/include file is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as published 8 * by the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program/include file is distributed in the hope that it will be 12 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty 13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program (in the main directory of the NTFS-3G 18 * distribution in the file COPYING); if not, write to the Free Software 19 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21 22 #ifdef HAVE_CONFIG_H 23 #include "config.h" 24 #endif 25 26 #ifdef HAVE_UNISTD_H 27 #include <unistd.h> 28 #endif 29 #ifdef HAVE_STDLIB_H 30 #include <stdlib.h> 31 #endif 32 #ifdef HAVE_STRING_H 33 #include <string.h> 34 #endif 35 #ifdef HAVE_ERRNO_H 36 #include <errno.h> 37 #endif 38 #ifdef HAVE_STDIO_H 39 #include <stdio.h> 40 #endif 41 #ifdef HAVE_SYS_TYPES_H 42 #include <sys/types.h> 43 #endif 44 #ifdef HAVE_SYS_STAT_H 45 #include <sys/stat.h> 46 #endif 47 #ifdef HAVE_FCNTL_H 48 #include <fcntl.h> 49 #endif 50 #ifdef HAVE_SYS_IOCTL_H 51 #include <sys/ioctl.h> 52 #endif 53 #ifdef HAVE_LINUX_FD_H 54 #include <linux/fd.h> 55 #endif 56 57 #include "types.h" 58 #include "mst.h" 59 #include "debug.h" 60 #include "device.h" 61 #include "logging.h" 62 #include "misc.h" 63 64 #define DEV_FD(dev) (*(int *)dev->d_private) 65 66 /* Define to nothing if not present on this system. */ 67 #ifndef O_EXCL 68 # define O_EXCL 0 69 #endif 70 71 /** 72 * ntfs_device_unix_io_open - Open a device and lock it exclusively 73 * @dev: 74 * @flags: 75 * 76 * Description... 77 * 78 * Returns: 79 */ 80 static int ntfs_device_unix_io_open(struct ntfs_device *dev, int flags) 81 { 82 struct flock flk; 83 struct stat sbuf; 84 int err; 85 86 if (NDevOpen(dev)) { 87 errno = EBUSY; 88 return -1; 89 } 90 if (stat(dev->d_name, &sbuf)) { 91 ntfs_log_perror("Failed to access '%s'", dev->d_name); 92 return -1; 93 } 94 if (S_ISBLK(sbuf.st_mode)) 95 NDevSetBlock(dev); 96 97 dev->d_private = ntfs_malloc(sizeof(int)); 98 if (!dev->d_private) 99 return -1; 100 /* 101 * Open file for exclusive access if mounting r/w. 102 * Fuseblk takes care about block devices. 103 */ 104 if (!NDevBlock(dev) && (flags & O_RDWR) == O_RDWR) 105 flags |= O_EXCL; 106 *(int*)dev->d_private = open(dev->d_name, flags); 107 if (*(int*)dev->d_private == -1) { 108 err = errno; 109 goto err_out; 110 } 111 112 if ((flags & O_RDWR) != O_RDWR) 113 NDevSetReadOnly(dev); 114 115 memset(&flk, 0, sizeof(flk)); 116 if (NDevReadOnly(dev)) 117 flk.l_type = F_RDLCK; 118 else 119 flk.l_type = F_WRLCK; 120 flk.l_whence = SEEK_SET; 121 flk.l_start = flk.l_len = 0LL; 122 if (fcntl(DEV_FD(dev), F_SETLK, &flk)) { 123 err = errno; 124 ntfs_log_perror("Failed to %s lock '%s'", NDevReadOnly(dev) ? 125 "read" : "write", dev->d_name); 126 if (close(DEV_FD(dev))) 127 ntfs_log_perror("Failed to close '%s'", dev->d_name); 128 goto err_out; 129 } 130 131 NDevSetOpen(dev); 132 return 0; 133 err_out: 134 free(dev->d_private); 135 dev->d_private = NULL; 136 errno = err; 137 return -1; 138 } 139 140 /** 141 * ntfs_device_unix_io_close - Close the device, releasing the lock 142 * @dev: 143 * 144 * Description... 145 * 146 * Returns: 147 */ 148 static int ntfs_device_unix_io_close(struct ntfs_device *dev) 149 { 150 struct flock flk; 151 152 if (!NDevOpen(dev)) { 153 errno = EBADF; 154 ntfs_log_perror("Device %s is not open", dev->d_name); 155 return -1; 156 } 157 if (NDevDirty(dev)) 158 if (fsync(DEV_FD(dev))) { 159 ntfs_log_perror("Failed to fsync device %s", dev->d_name); 160 return -1; 161 } 162 163 memset(&flk, 0, sizeof(flk)); 164 flk.l_type = F_UNLCK; 165 flk.l_whence = SEEK_SET; 166 flk.l_start = flk.l_len = 0LL; 167 if (fcntl(DEV_FD(dev), F_SETLK, &flk)) 168 ntfs_log_perror("Could not unlock %s", dev->d_name); 169 if (close(DEV_FD(dev))) { 170 ntfs_log_perror("Failed to close device %s", dev->d_name); 171 return -1; 172 } 173 NDevClearOpen(dev); 174 free(dev->d_private); 175 dev->d_private = NULL; 176 return 0; 177 } 178 179 /** 180 * ntfs_device_unix_io_seek - Seek to a place on the device 181 * @dev: 182 * @offset: 183 * @whence: 184 * 185 * Description... 186 * 187 * Returns: 188 */ 189 static s64 ntfs_device_unix_io_seek(struct ntfs_device *dev, s64 offset, 190 int whence) 191 { 192 return lseek(DEV_FD(dev), offset, whence); 193 } 194 195 /** 196 * ntfs_device_unix_io_read - Read from the device, from the current location 197 * @dev: 198 * @buf: 199 * @count: 200 * 201 * Description... 202 * 203 * Returns: 204 */ 205 static s64 ntfs_device_unix_io_read(struct ntfs_device *dev, void *buf, 206 s64 count) 207 { 208 return read(DEV_FD(dev), buf, count); 209 } 210 211 /** 212 * ntfs_device_unix_io_write - Write to the device, at the current location 213 * @dev: 214 * @buf: 215 * @count: 216 * 217 * Description... 218 * 219 * Returns: 220 */ 221 static s64 ntfs_device_unix_io_write(struct ntfs_device *dev, const void *buf, 222 s64 count) 223 { 224 if (NDevReadOnly(dev)) { 225 errno = EROFS; 226 return -1; 227 } 228 NDevSetDirty(dev); 229 return write(DEV_FD(dev), buf, count); 230 } 231 232 /** 233 * ntfs_device_unix_io_pread - Perform a positioned read from the device 234 * @dev: 235 * @buf: 236 * @count: 237 * @offset: 238 * 239 * Description... 240 * 241 * Returns: 242 */ 243 static s64 ntfs_device_unix_io_pread(struct ntfs_device *dev, void *buf, 244 s64 count, s64 offset) 245 { 246 return pread(DEV_FD(dev), buf, count, offset); 247 } 248 249 /** 250 * ntfs_device_unix_io_pwrite - Perform a positioned write to the device 251 * @dev: 252 * @buf: 253 * @count: 254 * @offset: 255 * 256 * Description... 257 * 258 * Returns: 259 */ 260 static s64 ntfs_device_unix_io_pwrite(struct ntfs_device *dev, const void *buf, 261 s64 count, s64 offset) 262 { 263 if (NDevReadOnly(dev)) { 264 errno = EROFS; 265 return -1; 266 } 267 NDevSetDirty(dev); 268 return pwrite(DEV_FD(dev), buf, count, offset); 269 } 270 271 /** 272 * ntfs_device_unix_io_sync - Flush any buffered changes to the device 273 * @dev: 274 * 275 * Description... 276 * 277 * Returns: 278 */ 279 static int ntfs_device_unix_io_sync(struct ntfs_device *dev) 280 { 281 int res = 0; 282 283 if (!NDevReadOnly(dev)) { 284 res = fsync(DEV_FD(dev)); 285 if (res) 286 ntfs_log_perror("Failed to sync device %s", dev->d_name); 287 else 288 NDevClearDirty(dev); 289 } 290 return res; 291 } 292 293 /** 294 * ntfs_device_unix_io_stat - Get information about the device 295 * @dev: 296 * @buf: 297 * 298 * Description... 299 * 300 * Returns: 301 */ 302 static int ntfs_device_unix_io_stat(struct ntfs_device *dev, struct stat *buf) 303 { 304 return fstat(DEV_FD(dev), buf); 305 } 306 307 /** 308 * ntfs_device_unix_io_ioctl - Perform an ioctl on the device 309 * @dev: 310 * @request: 311 * @argp: 312 * 313 * Description... 314 * 315 * Returns: 316 */ 317 static int ntfs_device_unix_io_ioctl(struct ntfs_device *dev, int request, 318 void *argp) 319 { 320 return ioctl(DEV_FD(dev), request, argp); 321 } 322 323 /** 324 * Device operations for working with unix style devices and files. 325 */ 326 struct ntfs_device_operations ntfs_device_unix_io_ops = { 327 .open = ntfs_device_unix_io_open, 328 .close = ntfs_device_unix_io_close, 329 .seek = ntfs_device_unix_io_seek, 330 .read = ntfs_device_unix_io_read, 331 .write = ntfs_device_unix_io_write, 332 .pread = ntfs_device_unix_io_pread, 333 .pwrite = ntfs_device_unix_io_pwrite, 334 .sync = ntfs_device_unix_io_sync, 335 .stat = ntfs_device_unix_io_stat, 336 .ioctl = ntfs_device_unix_io_ioctl, 337 }; 338