1 /* 2 * linux/fs/ioctl.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7 #include <linux/syscalls.h> 8 #include <linux/mm.h> 9 #include <linux/smp_lock.h> 10 #include <linux/capability.h> 11 #include <linux/file.h> 12 #include <linux/fs.h> 13 #include <linux/security.h> 14 #include <linux/module.h> 15 #include <linux/uaccess.h> 16 #include <linux/writeback.h> 17 #include <linux/buffer_head.h> 18 19 #include <asm/ioctls.h> 20 21 /* So that the fiemap access checks can't overflow on 32 bit machines. */ 22 #define FIEMAP_MAX_EXTENTS (UINT_MAX / sizeof(struct fiemap_extent)) 23 24 /** 25 * vfs_ioctl - call filesystem specific ioctl methods 26 * @filp: open file to invoke ioctl method on 27 * @cmd: ioctl command to execute 28 * @arg: command-specific argument for ioctl 29 * 30 * Invokes filesystem specific ->unlocked_ioctl, if one exists; otherwise 31 * invokes filesystem specific ->ioctl method. If neither method exists, 32 * returns -ENOTTY. 33 * 34 * Returns 0 on success, -errno on error. 35 */ 36 static long vfs_ioctl(struct file *filp, unsigned int cmd, 37 unsigned long arg) 38 { 39 int error = -ENOTTY; 40 41 if (!filp->f_op) 42 goto out; 43 44 if (filp->f_op->unlocked_ioctl) { 45 error = filp->f_op->unlocked_ioctl(filp, cmd, arg); 46 if (error == -ENOIOCTLCMD) 47 error = -EINVAL; 48 goto out; 49 } else if (filp->f_op->ioctl) { 50 lock_kernel(); 51 error = filp->f_op->ioctl(filp->f_path.dentry->d_inode, 52 filp, cmd, arg); 53 unlock_kernel(); 54 } 55 56 out: 57 return error; 58 } 59 60 static int ioctl_fibmap(struct file *filp, int __user *p) 61 { 62 struct address_space *mapping = filp->f_mapping; 63 int res, block; 64 65 /* do we support this mess? */ 66 if (!mapping->a_ops->bmap) 67 return -EINVAL; 68 if (!capable(CAP_SYS_RAWIO)) 69 return -EPERM; 70 res = get_user(block, p); 71 if (res) 72 return res; 73 lock_kernel(); 74 res = mapping->a_ops->bmap(mapping, block); 75 unlock_kernel(); 76 return put_user(res, p); 77 } 78 79 /** 80 * fiemap_fill_next_extent - Fiemap helper function 81 * @fieinfo: Fiemap context passed into ->fiemap 82 * @logical: Extent logical start offset, in bytes 83 * @phys: Extent physical start offset, in bytes 84 * @len: Extent length, in bytes 85 * @flags: FIEMAP_EXTENT flags that describe this extent 86 * 87 * Called from file system ->fiemap callback. Will populate extent 88 * info as passed in via arguments and copy to user memory. On 89 * success, extent count on fieinfo is incremented. 90 * 91 * Returns 0 on success, -errno on error, 1 if this was the last 92 * extent that will fit in user array. 93 */ 94 #define SET_UNKNOWN_FLAGS (FIEMAP_EXTENT_DELALLOC) 95 #define SET_NO_UNMOUNTED_IO_FLAGS (FIEMAP_EXTENT_DATA_ENCRYPTED) 96 #define SET_NOT_ALIGNED_FLAGS (FIEMAP_EXTENT_DATA_TAIL|FIEMAP_EXTENT_DATA_INLINE) 97 int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical, 98 u64 phys, u64 len, u32 flags) 99 { 100 struct fiemap_extent extent; 101 struct fiemap_extent *dest = fieinfo->fi_extents_start; 102 103 /* only count the extents */ 104 if (fieinfo->fi_extents_max == 0) { 105 fieinfo->fi_extents_mapped++; 106 return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0; 107 } 108 109 if (fieinfo->fi_extents_mapped >= fieinfo->fi_extents_max) 110 return 1; 111 112 if (flags & SET_UNKNOWN_FLAGS) 113 flags |= FIEMAP_EXTENT_UNKNOWN; 114 if (flags & SET_NO_UNMOUNTED_IO_FLAGS) 115 flags |= FIEMAP_EXTENT_ENCODED; 116 if (flags & SET_NOT_ALIGNED_FLAGS) 117 flags |= FIEMAP_EXTENT_NOT_ALIGNED; 118 119 memset(&extent, 0, sizeof(extent)); 120 extent.fe_logical = logical; 121 extent.fe_physical = phys; 122 extent.fe_length = len; 123 extent.fe_flags = flags; 124 125 dest += fieinfo->fi_extents_mapped; 126 if (copy_to_user(dest, &extent, sizeof(extent))) 127 return -EFAULT; 128 129 fieinfo->fi_extents_mapped++; 130 if (fieinfo->fi_extents_mapped == fieinfo->fi_extents_max) 131 return 1; 132 return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0; 133 } 134 EXPORT_SYMBOL(fiemap_fill_next_extent); 135 136 /** 137 * fiemap_check_flags - check validity of requested flags for fiemap 138 * @fieinfo: Fiemap context passed into ->fiemap 139 * @fs_flags: Set of fiemap flags that the file system understands 140 * 141 * Called from file system ->fiemap callback. This will compute the 142 * intersection of valid fiemap flags and those that the fs supports. That 143 * value is then compared against the user supplied flags. In case of bad user 144 * flags, the invalid values will be written into the fieinfo structure, and 145 * -EBADR is returned, which tells ioctl_fiemap() to return those values to 146 * userspace. For this reason, a return code of -EBADR should be preserved. 147 * 148 * Returns 0 on success, -EBADR on bad flags. 149 */ 150 int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags) 151 { 152 u32 incompat_flags; 153 154 incompat_flags = fieinfo->fi_flags & ~(FIEMAP_FLAGS_COMPAT & fs_flags); 155 if (incompat_flags) { 156 fieinfo->fi_flags = incompat_flags; 157 return -EBADR; 158 } 159 return 0; 160 } 161 EXPORT_SYMBOL(fiemap_check_flags); 162 163 static int fiemap_check_ranges(struct super_block *sb, 164 u64 start, u64 len, u64 *new_len) 165 { 166 *new_len = len; 167 168 if (len == 0) 169 return -EINVAL; 170 171 if (start > sb->s_maxbytes) 172 return -EFBIG; 173 174 /* 175 * Shrink request scope to what the fs can actually handle. 176 */ 177 if ((len > sb->s_maxbytes) || 178 (sb->s_maxbytes - len) < start) 179 *new_len = sb->s_maxbytes - start; 180 181 return 0; 182 } 183 184 static int ioctl_fiemap(struct file *filp, unsigned long arg) 185 { 186 struct fiemap fiemap; 187 struct fiemap_extent_info fieinfo = { 0, }; 188 struct inode *inode = filp->f_path.dentry->d_inode; 189 struct super_block *sb = inode->i_sb; 190 u64 len; 191 int error; 192 193 if (!inode->i_op->fiemap) 194 return -EOPNOTSUPP; 195 196 if (copy_from_user(&fiemap, (struct fiemap __user *)arg, 197 sizeof(struct fiemap))) 198 return -EFAULT; 199 200 if (fiemap.fm_extent_count > FIEMAP_MAX_EXTENTS) 201 return -EINVAL; 202 203 error = fiemap_check_ranges(sb, fiemap.fm_start, fiemap.fm_length, 204 &len); 205 if (error) 206 return error; 207 208 fieinfo.fi_flags = fiemap.fm_flags; 209 fieinfo.fi_extents_max = fiemap.fm_extent_count; 210 fieinfo.fi_extents_start = (struct fiemap_extent *)(arg + sizeof(fiemap)); 211 212 if (fiemap.fm_extent_count != 0 && 213 !access_ok(VERIFY_WRITE, fieinfo.fi_extents_start, 214 fieinfo.fi_extents_max * sizeof(struct fiemap_extent))) 215 return -EFAULT; 216 217 if (fieinfo.fi_flags & FIEMAP_FLAG_SYNC) 218 filemap_write_and_wait(inode->i_mapping); 219 220 error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start, len); 221 fiemap.fm_flags = fieinfo.fi_flags; 222 fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped; 223 if (copy_to_user((char *)arg, &fiemap, sizeof(fiemap))) 224 error = -EFAULT; 225 226 return error; 227 } 228 229 #ifdef CONFIG_BLOCK 230 231 #define blk_to_logical(inode, blk) (blk << (inode)->i_blkbits) 232 #define logical_to_blk(inode, offset) (offset >> (inode)->i_blkbits); 233 234 /* 235 * @inode - the inode to map 236 * @arg - the pointer to userspace where we copy everything to 237 * @get_block - the fs's get_block function 238 * 239 * This does FIEMAP for block based inodes. Basically it will just loop 240 * through get_block until we hit the number of extents we want to map, or we 241 * go past the end of the file and hit a hole. 242 * 243 * If it is possible to have data blocks beyond a hole past @inode->i_size, then 244 * please do not use this function, it will stop at the first unmapped block 245 * beyond i_size 246 */ 247 int generic_block_fiemap(struct inode *inode, 248 struct fiemap_extent_info *fieinfo, u64 start, 249 u64 len, get_block_t *get_block) 250 { 251 struct buffer_head tmp; 252 unsigned int start_blk; 253 long long length = 0, map_len = 0; 254 u64 logical = 0, phys = 0, size = 0; 255 u32 flags = FIEMAP_EXTENT_MERGED; 256 int ret = 0; 257 258 if ((ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC))) 259 return ret; 260 261 start_blk = logical_to_blk(inode, start); 262 263 /* guard against change */ 264 mutex_lock(&inode->i_mutex); 265 266 length = (long long)min_t(u64, len, i_size_read(inode)); 267 map_len = length; 268 269 do { 270 /* 271 * we set b_size to the total size we want so it will map as 272 * many contiguous blocks as possible at once 273 */ 274 memset(&tmp, 0, sizeof(struct buffer_head)); 275 tmp.b_size = map_len; 276 277 ret = get_block(inode, start_blk, &tmp, 0); 278 if (ret) 279 break; 280 281 /* HOLE */ 282 if (!buffer_mapped(&tmp)) { 283 /* 284 * first hole after going past the EOF, this is our 285 * last extent 286 */ 287 if (length <= 0) { 288 flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST; 289 ret = fiemap_fill_next_extent(fieinfo, logical, 290 phys, size, 291 flags); 292 break; 293 } 294 295 length -= blk_to_logical(inode, 1); 296 297 /* if we have holes up to/past EOF then we're done */ 298 if (length <= 0) 299 break; 300 301 start_blk++; 302 } else { 303 if (length <= 0 && size) { 304 ret = fiemap_fill_next_extent(fieinfo, logical, 305 phys, size, 306 flags); 307 if (ret) 308 break; 309 } 310 311 logical = blk_to_logical(inode, start_blk); 312 phys = blk_to_logical(inode, tmp.b_blocknr); 313 size = tmp.b_size; 314 flags = FIEMAP_EXTENT_MERGED; 315 316 length -= tmp.b_size; 317 start_blk += logical_to_blk(inode, size); 318 319 /* 320 * if we are past the EOF we need to loop again to see 321 * if there is a hole so we can mark this extent as the 322 * last one, and if not keep mapping things until we 323 * find a hole, or we run out of slots in the extent 324 * array 325 */ 326 if (length <= 0) 327 continue; 328 329 ret = fiemap_fill_next_extent(fieinfo, logical, phys, 330 size, flags); 331 if (ret) 332 break; 333 } 334 cond_resched(); 335 } while (1); 336 337 mutex_unlock(&inode->i_mutex); 338 339 /* if ret is 1 then we just hit the end of the extent array */ 340 if (ret == 1) 341 ret = 0; 342 343 return ret; 344 } 345 EXPORT_SYMBOL(generic_block_fiemap); 346 347 #endif /* CONFIG_BLOCK */ 348 349 static int file_ioctl(struct file *filp, unsigned int cmd, 350 unsigned long arg) 351 { 352 struct inode *inode = filp->f_path.dentry->d_inode; 353 int __user *p = (int __user *)arg; 354 355 switch (cmd) { 356 case FIBMAP: 357 return ioctl_fibmap(filp, p); 358 case FS_IOC_FIEMAP: 359 return ioctl_fiemap(filp, arg); 360 case FIGETBSZ: 361 return put_user(inode->i_sb->s_blocksize, p); 362 case FIONREAD: 363 return put_user(i_size_read(inode) - filp->f_pos, p); 364 } 365 366 return vfs_ioctl(filp, cmd, arg); 367 } 368 369 static int ioctl_fionbio(struct file *filp, int __user *argp) 370 { 371 unsigned int flag; 372 int on, error; 373 374 error = get_user(on, argp); 375 if (error) 376 return error; 377 flag = O_NONBLOCK; 378 #ifdef __sparc__ 379 /* SunOS compatibility item. */ 380 if (O_NONBLOCK != O_NDELAY) 381 flag |= O_NDELAY; 382 #endif 383 if (on) 384 filp->f_flags |= flag; 385 else 386 filp->f_flags &= ~flag; 387 return error; 388 } 389 390 static int ioctl_fioasync(unsigned int fd, struct file *filp, 391 int __user *argp) 392 { 393 unsigned int flag; 394 int on, error; 395 396 error = get_user(on, argp); 397 if (error) 398 return error; 399 flag = on ? FASYNC : 0; 400 401 /* Did FASYNC state change ? */ 402 if ((flag ^ filp->f_flags) & FASYNC) { 403 if (filp->f_op && filp->f_op->fasync) { 404 lock_kernel(); 405 error = filp->f_op->fasync(fd, filp, on); 406 unlock_kernel(); 407 } else 408 error = -ENOTTY; 409 } 410 if (error) 411 return error; 412 413 if (on) 414 filp->f_flags |= FASYNC; 415 else 416 filp->f_flags &= ~FASYNC; 417 return error; 418 } 419 420 /* 421 * When you add any new common ioctls to the switches above and below 422 * please update compat_sys_ioctl() too. 423 * 424 * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d. 425 * It's just a simple helper for sys_ioctl and compat_sys_ioctl. 426 */ 427 int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, 428 unsigned long arg) 429 { 430 int error = 0; 431 int __user *argp = (int __user *)arg; 432 433 switch (cmd) { 434 case FIOCLEX: 435 set_close_on_exec(fd, 1); 436 break; 437 438 case FIONCLEX: 439 set_close_on_exec(fd, 0); 440 break; 441 442 case FIONBIO: 443 error = ioctl_fionbio(filp, argp); 444 break; 445 446 case FIOASYNC: 447 error = ioctl_fioasync(fd, filp, argp); 448 break; 449 450 case FIOQSIZE: 451 if (S_ISDIR(filp->f_path.dentry->d_inode->i_mode) || 452 S_ISREG(filp->f_path.dentry->d_inode->i_mode) || 453 S_ISLNK(filp->f_path.dentry->d_inode->i_mode)) { 454 loff_t res = 455 inode_get_bytes(filp->f_path.dentry->d_inode); 456 error = copy_to_user((loff_t __user *)arg, &res, 457 sizeof(res)) ? -EFAULT : 0; 458 } else 459 error = -ENOTTY; 460 break; 461 default: 462 if (S_ISREG(filp->f_path.dentry->d_inode->i_mode)) 463 error = file_ioctl(filp, cmd, arg); 464 else 465 error = vfs_ioctl(filp, cmd, arg); 466 break; 467 } 468 return error; 469 } 470 471 asmlinkage long sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg) 472 { 473 struct file *filp; 474 int error = -EBADF; 475 int fput_needed; 476 477 filp = fget_light(fd, &fput_needed); 478 if (!filp) 479 goto out; 480 481 error = security_file_ioctl(filp, cmd, arg); 482 if (error) 483 goto out_fput; 484 485 error = do_vfs_ioctl(filp, fd, cmd, arg); 486 out_fput: 487 fput_light(filp, fput_needed); 488 out: 489 return error; 490 } 491