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 * __generic_block_fiemap - FIEMAP for block based inodes (no locking) 236 * @inode - the inode to map 237 * @arg - the pointer to userspace where we copy everything to 238 * @get_block - the fs's get_block function 239 * 240 * This does FIEMAP for block based inodes. Basically it will just loop 241 * through get_block until we hit the number of extents we want to map, or we 242 * go past the end of the file and hit a hole. 243 * 244 * If it is possible to have data blocks beyond a hole past @inode->i_size, then 245 * please do not use this function, it will stop at the first unmapped block 246 * beyond i_size. 247 * 248 * If you use this function directly, you need to do your own locking. Use 249 * generic_block_fiemap if you want the locking done for you. 250 */ 251 252 int __generic_block_fiemap(struct inode *inode, 253 struct fiemap_extent_info *fieinfo, u64 start, 254 u64 len, get_block_t *get_block) 255 { 256 struct buffer_head tmp; 257 unsigned int start_blk; 258 long long length = 0, map_len = 0; 259 u64 logical = 0, phys = 0, size = 0; 260 u32 flags = FIEMAP_EXTENT_MERGED; 261 int ret = 0, past_eof = 0, whole_file = 0; 262 263 if ((ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC))) 264 return ret; 265 266 start_blk = logical_to_blk(inode, start); 267 268 length = (long long)min_t(u64, len, i_size_read(inode)); 269 if (length < len) 270 whole_file = 1; 271 272 map_len = length; 273 274 do { 275 /* 276 * we set b_size to the total size we want so it will map as 277 * many contiguous blocks as possible at once 278 */ 279 memset(&tmp, 0, sizeof(struct buffer_head)); 280 tmp.b_size = map_len; 281 282 ret = get_block(inode, start_blk, &tmp, 0); 283 if (ret) 284 break; 285 286 /* HOLE */ 287 if (!buffer_mapped(&tmp)) { 288 length -= blk_to_logical(inode, 1); 289 start_blk++; 290 291 /* 292 * we want to handle the case where there is an 293 * allocated block at the front of the file, and then 294 * nothing but holes up to the end of the file properly, 295 * to make sure that extent at the front gets properly 296 * marked with FIEMAP_EXTENT_LAST 297 */ 298 if (!past_eof && 299 blk_to_logical(inode, start_blk) >= 300 blk_to_logical(inode, 0)+i_size_read(inode)) 301 past_eof = 1; 302 303 /* 304 * first hole after going past the EOF, this is our 305 * last extent 306 */ 307 if (past_eof && size) { 308 flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST; 309 ret = fiemap_fill_next_extent(fieinfo, logical, 310 phys, size, 311 flags); 312 break; 313 } 314 315 /* if we have holes up to/past EOF then we're done */ 316 if (length <= 0 || past_eof) 317 break; 318 } else { 319 /* 320 * we have gone over the length of what we wanted to 321 * map, and it wasn't the entire file, so add the extent 322 * we got last time and exit. 323 * 324 * This is for the case where say we want to map all the 325 * way up to the second to the last block in a file, but 326 * the last block is a hole, making the second to last 327 * block FIEMAP_EXTENT_LAST. In this case we want to 328 * see if there is a hole after the second to last block 329 * so we can mark it properly. If we found data after 330 * we exceeded the length we were requesting, then we 331 * are good to go, just add the extent to the fieinfo 332 * and break 333 */ 334 if (length <= 0 && !whole_file) { 335 ret = fiemap_fill_next_extent(fieinfo, logical, 336 phys, size, 337 flags); 338 break; 339 } 340 341 /* 342 * if size != 0 then we know we already have an extent 343 * to add, so add it. 344 */ 345 if (size) { 346 ret = fiemap_fill_next_extent(fieinfo, logical, 347 phys, size, 348 flags); 349 if (ret) 350 break; 351 } 352 353 logical = blk_to_logical(inode, start_blk); 354 phys = blk_to_logical(inode, tmp.b_blocknr); 355 size = tmp.b_size; 356 flags = FIEMAP_EXTENT_MERGED; 357 358 length -= tmp.b_size; 359 start_blk += logical_to_blk(inode, size); 360 361 /* 362 * If we are past the EOF, then we need to make sure as 363 * soon as we find a hole that the last extent we found 364 * is marked with FIEMAP_EXTENT_LAST 365 */ 366 if (!past_eof && 367 logical+size >= 368 blk_to_logical(inode, 0)+i_size_read(inode)) 369 past_eof = 1; 370 } 371 cond_resched(); 372 } while (1); 373 374 /* if ret is 1 then we just hit the end of the extent array */ 375 if (ret == 1) 376 ret = 0; 377 378 return ret; 379 } 380 EXPORT_SYMBOL(__generic_block_fiemap); 381 382 /** 383 * generic_block_fiemap - FIEMAP for block based inodes 384 * @inode: The inode to map 385 * @fieinfo: The mapping information 386 * @start: The initial block to map 387 * @len: The length of the extect to attempt to map 388 * @get_block: The block mapping function for the fs 389 * 390 * Calls __generic_block_fiemap to map the inode, after taking 391 * the inode's mutex lock. 392 */ 393 394 int generic_block_fiemap(struct inode *inode, 395 struct fiemap_extent_info *fieinfo, u64 start, 396 u64 len, get_block_t *get_block) 397 { 398 int ret; 399 mutex_lock(&inode->i_mutex); 400 ret = __generic_block_fiemap(inode, fieinfo, start, len, get_block); 401 mutex_unlock(&inode->i_mutex); 402 return ret; 403 } 404 EXPORT_SYMBOL(generic_block_fiemap); 405 406 #endif /* CONFIG_BLOCK */ 407 408 static int file_ioctl(struct file *filp, unsigned int cmd, 409 unsigned long arg) 410 { 411 struct inode *inode = filp->f_path.dentry->d_inode; 412 int __user *p = (int __user *)arg; 413 414 switch (cmd) { 415 case FIBMAP: 416 return ioctl_fibmap(filp, p); 417 case FS_IOC_FIEMAP: 418 return ioctl_fiemap(filp, arg); 419 case FIGETBSZ: 420 return put_user(inode->i_sb->s_blocksize, p); 421 case FIONREAD: 422 return put_user(i_size_read(inode) - filp->f_pos, p); 423 } 424 425 return vfs_ioctl(filp, cmd, arg); 426 } 427 428 static int ioctl_fionbio(struct file *filp, int __user *argp) 429 { 430 unsigned int flag; 431 int on, error; 432 433 error = get_user(on, argp); 434 if (error) 435 return error; 436 flag = O_NONBLOCK; 437 #ifdef __sparc__ 438 /* SunOS compatibility item. */ 439 if (O_NONBLOCK != O_NDELAY) 440 flag |= O_NDELAY; 441 #endif 442 spin_lock(&filp->f_lock); 443 if (on) 444 filp->f_flags |= flag; 445 else 446 filp->f_flags &= ~flag; 447 spin_unlock(&filp->f_lock); 448 return error; 449 } 450 451 static int ioctl_fioasync(unsigned int fd, struct file *filp, 452 int __user *argp) 453 { 454 unsigned int flag; 455 int on, error; 456 457 error = get_user(on, argp); 458 if (error) 459 return error; 460 flag = on ? FASYNC : 0; 461 462 /* Did FASYNC state change ? */ 463 if ((flag ^ filp->f_flags) & FASYNC) { 464 if (filp->f_op && filp->f_op->fasync) 465 /* fasync() adjusts filp->f_flags */ 466 error = filp->f_op->fasync(fd, filp, on); 467 else 468 error = -ENOTTY; 469 } 470 return error < 0 ? error : 0; 471 } 472 473 static int ioctl_fsfreeze(struct file *filp) 474 { 475 struct super_block *sb = filp->f_path.dentry->d_inode->i_sb; 476 477 if (!capable(CAP_SYS_ADMIN)) 478 return -EPERM; 479 480 /* If filesystem doesn't support freeze feature, return. */ 481 if (sb->s_op->freeze_fs == NULL) 482 return -EOPNOTSUPP; 483 484 /* If a blockdevice-backed filesystem isn't specified, return. */ 485 if (sb->s_bdev == NULL) 486 return -EINVAL; 487 488 /* Freeze */ 489 sb = freeze_bdev(sb->s_bdev); 490 if (IS_ERR(sb)) 491 return PTR_ERR(sb); 492 return 0; 493 } 494 495 static int ioctl_fsthaw(struct file *filp) 496 { 497 struct super_block *sb = filp->f_path.dentry->d_inode->i_sb; 498 499 if (!capable(CAP_SYS_ADMIN)) 500 return -EPERM; 501 502 /* If a blockdevice-backed filesystem isn't specified, return EINVAL. */ 503 if (sb->s_bdev == NULL) 504 return -EINVAL; 505 506 /* Thaw */ 507 return thaw_bdev(sb->s_bdev, sb); 508 } 509 510 /* 511 * When you add any new common ioctls to the switches above and below 512 * please update compat_sys_ioctl() too. 513 * 514 * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d. 515 * It's just a simple helper for sys_ioctl and compat_sys_ioctl. 516 */ 517 int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, 518 unsigned long arg) 519 { 520 int error = 0; 521 int __user *argp = (int __user *)arg; 522 523 switch (cmd) { 524 case FIOCLEX: 525 set_close_on_exec(fd, 1); 526 break; 527 528 case FIONCLEX: 529 set_close_on_exec(fd, 0); 530 break; 531 532 case FIONBIO: 533 error = ioctl_fionbio(filp, argp); 534 break; 535 536 case FIOASYNC: 537 error = ioctl_fioasync(fd, filp, argp); 538 break; 539 540 case FIOQSIZE: 541 if (S_ISDIR(filp->f_path.dentry->d_inode->i_mode) || 542 S_ISREG(filp->f_path.dentry->d_inode->i_mode) || 543 S_ISLNK(filp->f_path.dentry->d_inode->i_mode)) { 544 loff_t res = 545 inode_get_bytes(filp->f_path.dentry->d_inode); 546 error = copy_to_user((loff_t __user *)arg, &res, 547 sizeof(res)) ? -EFAULT : 0; 548 } else 549 error = -ENOTTY; 550 break; 551 552 case FIFREEZE: 553 error = ioctl_fsfreeze(filp); 554 break; 555 556 case FITHAW: 557 error = ioctl_fsthaw(filp); 558 break; 559 560 default: 561 if (S_ISREG(filp->f_path.dentry->d_inode->i_mode)) 562 error = file_ioctl(filp, cmd, arg); 563 else 564 error = vfs_ioctl(filp, cmd, arg); 565 break; 566 } 567 return error; 568 } 569 570 SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) 571 { 572 struct file *filp; 573 int error = -EBADF; 574 int fput_needed; 575 576 filp = fget_light(fd, &fput_needed); 577 if (!filp) 578 goto out; 579 580 error = security_file_ioctl(filp, cmd, arg); 581 if (error) 582 goto out_fput; 583 584 error = do_vfs_ioctl(filp, fd, cmd, arg); 585 out_fput: 586 fput_light(filp, fput_needed); 587 out: 588 return error; 589 } 590