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/capability.h> 10#include <linux/file.h> 11#include <linux/fs.h> 12#include <linux/security.h> 13#include <linux/export.h> 14#include <linux/uaccess.h> 15#include <linux/writeback.h> 16#include <linux/buffer_head.h> 17#include <linux/falloc.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 * returns -ENOTTY. 32 * 33 * Returns 0 on success, -errno on error. 34 */ 35static long vfs_ioctl(struct file *filp, unsigned int cmd, 36 unsigned long arg) 37{ 38 int error = -ENOTTY; 39 40 if (!filp->f_op->unlocked_ioctl) 41 goto out; 42 43 error = filp->f_op->unlocked_ioctl(filp, cmd, arg); 44 if (error == -ENOIOCTLCMD) 45 error = -ENOTTY; 46 out: 47 return error; 48} 49 50static int ioctl_fibmap(struct file *filp, int __user *p) 51{ 52 struct address_space *mapping = filp->f_mapping; 53 int res, block; 54 55 /* do we support this mess? */ 56 if (!mapping->a_ops->bmap) 57 return -EINVAL; 58 if (!capable(CAP_SYS_RAWIO)) 59 return -EPERM; 60 res = get_user(block, p); 61 if (res) 62 return res; 63 res = mapping->a_ops->bmap(mapping, block); 64 return put_user(res, p); 65} 66 67/** 68 * fiemap_fill_next_extent - Fiemap helper function 69 * @fieinfo: Fiemap context passed into ->fiemap 70 * @logical: Extent logical start offset, in bytes 71 * @phys: Extent physical start offset, in bytes 72 * @len: Extent length, in bytes 73 * @flags: FIEMAP_EXTENT flags that describe this extent 74 * 75 * Called from file system ->fiemap callback. Will populate extent 76 * info as passed in via arguments and copy to user memory. On 77 * success, extent count on fieinfo is incremented. 78 * 79 * Returns 0 on success, -errno on error, 1 if this was the last 80 * extent that will fit in user array. 81 */ 82#define SET_UNKNOWN_FLAGS (FIEMAP_EXTENT_DELALLOC) 83#define SET_NO_UNMOUNTED_IO_FLAGS (FIEMAP_EXTENT_DATA_ENCRYPTED) 84#define SET_NOT_ALIGNED_FLAGS (FIEMAP_EXTENT_DATA_TAIL|FIEMAP_EXTENT_DATA_INLINE) 85int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical, 86 u64 phys, u64 len, u32 flags) 87{ 88 struct fiemap_extent extent; 89 struct fiemap_extent __user *dest = fieinfo->fi_extents_start; 90 91 /* only count the extents */ 92 if (fieinfo->fi_extents_max == 0) { 93 fieinfo->fi_extents_mapped++; 94 return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0; 95 } 96 97 if (fieinfo->fi_extents_mapped >= fieinfo->fi_extents_max) 98 return 1; 99 100 if (flags & SET_UNKNOWN_FLAGS) 101 flags |= FIEMAP_EXTENT_UNKNOWN; 102 if (flags & SET_NO_UNMOUNTED_IO_FLAGS) 103 flags |= FIEMAP_EXTENT_ENCODED; 104 if (flags & SET_NOT_ALIGNED_FLAGS) 105 flags |= FIEMAP_EXTENT_NOT_ALIGNED; 106 107 memset(&extent, 0, sizeof(extent)); 108 extent.fe_logical = logical; 109 extent.fe_physical = phys; 110 extent.fe_length = len; 111 extent.fe_flags = flags; 112 113 dest += fieinfo->fi_extents_mapped; 114 if (copy_to_user(dest, &extent, sizeof(extent))) 115 return -EFAULT; 116 117 fieinfo->fi_extents_mapped++; 118 if (fieinfo->fi_extents_mapped == fieinfo->fi_extents_max) 119 return 1; 120 return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0; 121} 122EXPORT_SYMBOL(fiemap_fill_next_extent); 123 124/** 125 * fiemap_check_flags - check validity of requested flags for fiemap 126 * @fieinfo: Fiemap context passed into ->fiemap 127 * @fs_flags: Set of fiemap flags that the file system understands 128 * 129 * Called from file system ->fiemap callback. This will compute the 130 * intersection of valid fiemap flags and those that the fs supports. That 131 * value is then compared against the user supplied flags. In case of bad user 132 * flags, the invalid values will be written into the fieinfo structure, and 133 * -EBADR is returned, which tells ioctl_fiemap() to return those values to 134 * userspace. For this reason, a return code of -EBADR should be preserved. 135 * 136 * Returns 0 on success, -EBADR on bad flags. 137 */ 138int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags) 139{ 140 u32 incompat_flags; 141 142 incompat_flags = fieinfo->fi_flags & ~(FIEMAP_FLAGS_COMPAT & fs_flags); 143 if (incompat_flags) { 144 fieinfo->fi_flags = incompat_flags; 145 return -EBADR; 146 } 147 return 0; 148} 149EXPORT_SYMBOL(fiemap_check_flags); 150 151static int fiemap_check_ranges(struct super_block *sb, 152 u64 start, u64 len, u64 *new_len) 153{ 154 u64 maxbytes = (u64) sb->s_maxbytes; 155 156 *new_len = len; 157 158 if (len == 0) 159 return -EINVAL; 160 161 if (start > maxbytes) 162 return -EFBIG; 163 164 /* 165 * Shrink request scope to what the fs can actually handle. 166 */ 167 if (len > maxbytes || (maxbytes - len) < start) 168 *new_len = maxbytes - start; 169 170 return 0; 171} 172 173static int ioctl_fiemap(struct file *filp, unsigned long arg) 174{ 175 struct fiemap fiemap; 176 struct fiemap __user *ufiemap = (struct fiemap __user *) arg; 177 struct fiemap_extent_info fieinfo = { 0, }; 178 struct inode *inode = file_inode(filp); 179 struct super_block *sb = inode->i_sb; 180 u64 len; 181 int error; 182 183 if (!inode->i_op->fiemap) 184 return -EOPNOTSUPP; 185 186 if (copy_from_user(&fiemap, ufiemap, sizeof(fiemap))) 187 return -EFAULT; 188 189 if (fiemap.fm_extent_count > FIEMAP_MAX_EXTENTS) 190 return -EINVAL; 191 192 error = fiemap_check_ranges(sb, fiemap.fm_start, fiemap.fm_length, 193 &len); 194 if (error) 195 return error; 196 197 fieinfo.fi_flags = fiemap.fm_flags; 198 fieinfo.fi_extents_max = fiemap.fm_extent_count; 199 fieinfo.fi_extents_start = ufiemap->fm_extents; 200 201 if (fiemap.fm_extent_count != 0 && 202 !access_ok(VERIFY_WRITE, fieinfo.fi_extents_start, 203 fieinfo.fi_extents_max * sizeof(struct fiemap_extent))) 204 return -EFAULT; 205 206 if (fieinfo.fi_flags & FIEMAP_FLAG_SYNC) 207 filemap_write_and_wait(inode->i_mapping); 208 209 error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start, len); 210 fiemap.fm_flags = fieinfo.fi_flags; 211 fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped; 212 if (copy_to_user(ufiemap, &fiemap, sizeof(fiemap))) 213 error = -EFAULT; 214 215 return error; 216} 217 218#ifdef CONFIG_BLOCK 219 220static inline sector_t logical_to_blk(struct inode *inode, loff_t offset) 221{ 222 return (offset >> inode->i_blkbits); 223} 224 225static inline loff_t blk_to_logical(struct inode *inode, sector_t blk) 226{ 227 return (blk << inode->i_blkbits); 228} 229 230/** 231 * __generic_block_fiemap - FIEMAP for block based inodes (no locking) 232 * @inode: the inode to map 233 * @fieinfo: the fiemap info struct that will be passed back to userspace 234 * @start: where to start mapping in the inode 235 * @len: how much space to map 236 * @get_block: the fs's get_block function 237 * 238 * This does FIEMAP for block based inodes. Basically it will just loop 239 * through get_block until we hit the number of extents we want to map, or we 240 * go past the end of the file and hit a hole. 241 * 242 * If it is possible to have data blocks beyond a hole past @inode->i_size, then 243 * please do not use this function, it will stop at the first unmapped block 244 * beyond i_size. 245 * 246 * If you use this function directly, you need to do your own locking. Use 247 * generic_block_fiemap if you want the locking done for you. 248 */ 249 250int __generic_block_fiemap(struct inode *inode, 251 struct fiemap_extent_info *fieinfo, loff_t start, 252 loff_t len, get_block_t *get_block) 253{ 254 struct buffer_head map_bh; 255 sector_t start_blk, last_blk; 256 loff_t isize = i_size_read(inode); 257 u64 logical = 0, phys = 0, size = 0; 258 u32 flags = FIEMAP_EXTENT_MERGED; 259 bool past_eof = false, whole_file = false; 260 int ret = 0; 261 262 ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC); 263 if (ret) 264 return ret; 265 266 /* 267 * Either the i_mutex or other appropriate locking needs to be held 268 * since we expect isize to not change at all through the duration of 269 * this call. 270 */ 271 if (len >= isize) { 272 whole_file = true; 273 len = isize; 274 } 275 276 /* 277 * Some filesystems can't deal with being asked to map less than 278 * blocksize, so make sure our len is at least block length. 279 */ 280 if (logical_to_blk(inode, len) == 0) 281 len = blk_to_logical(inode, 1); 282 283 start_blk = logical_to_blk(inode, start); 284 last_blk = logical_to_blk(inode, start + len - 1); 285 286 do { 287 /* 288 * we set b_size to the total size we want so it will map as 289 * many contiguous blocks as possible at once 290 */ 291 memset(&map_bh, 0, sizeof(struct buffer_head)); 292 map_bh.b_size = len; 293 294 ret = get_block(inode, start_blk, &map_bh, 0); 295 if (ret) 296 break; 297 298 /* HOLE */ 299 if (!buffer_mapped(&map_bh)) { 300 start_blk++; 301 302 /* 303 * We want to handle the case where there is an 304 * allocated block at the front of the file, and then 305 * nothing but holes up to the end of the file properly, 306 * to make sure that extent at the front gets properly 307 * marked with FIEMAP_EXTENT_LAST 308 */ 309 if (!past_eof && 310 blk_to_logical(inode, start_blk) >= isize) 311 past_eof = 1; 312 313 /* 314 * First hole after going past the EOF, this is our 315 * last extent 316 */ 317 if (past_eof && size) { 318 flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST; 319 ret = fiemap_fill_next_extent(fieinfo, logical, 320 phys, size, 321 flags); 322 } else if (size) { 323 ret = fiemap_fill_next_extent(fieinfo, logical, 324 phys, size, flags); 325 size = 0; 326 } 327 328 /* if we have holes up to/past EOF then we're done */ 329 if (start_blk > last_blk || past_eof || ret) 330 break; 331 } else { 332 /* 333 * We have gone over the length of what we wanted to 334 * map, and it wasn't the entire file, so add the extent 335 * we got last time and exit. 336 * 337 * This is for the case where say we want to map all the 338 * way up to the second to the last block in a file, but 339 * the last block is a hole, making the second to last 340 * block FIEMAP_EXTENT_LAST. In this case we want to 341 * see if there is a hole after the second to last block 342 * so we can mark it properly. If we found data after 343 * we exceeded the length we were requesting, then we 344 * are good to go, just add the extent to the fieinfo 345 * and break 346 */ 347 if (start_blk > last_blk && !whole_file) { 348 ret = fiemap_fill_next_extent(fieinfo, logical, 349 phys, size, 350 flags); 351 break; 352 } 353 354 /* 355 * if size != 0 then we know we already have an extent 356 * to add, so add it. 357 */ 358 if (size) { 359 ret = fiemap_fill_next_extent(fieinfo, logical, 360 phys, size, 361 flags); 362 if (ret) 363 break; 364 } 365 366 logical = blk_to_logical(inode, start_blk); 367 phys = blk_to_logical(inode, map_bh.b_blocknr); 368 size = map_bh.b_size; 369 flags = FIEMAP_EXTENT_MERGED; 370 371 start_blk += logical_to_blk(inode, size); 372 373 /* 374 * If we are past the EOF, then we need to make sure as 375 * soon as we find a hole that the last extent we found 376 * is marked with FIEMAP_EXTENT_LAST 377 */ 378 if (!past_eof && logical + size >= isize) 379 past_eof = true; 380 } 381 cond_resched(); 382 if (fatal_signal_pending(current)) { 383 ret = -EINTR; 384 break; 385 } 386 387 } while (1); 388 389 /* If ret is 1 then we just hit the end of the extent array */ 390 if (ret == 1) 391 ret = 0; 392 393 return ret; 394} 395EXPORT_SYMBOL(__generic_block_fiemap); 396 397/** 398 * generic_block_fiemap - FIEMAP for block based inodes 399 * @inode: The inode to map 400 * @fieinfo: The mapping information 401 * @start: The initial block to map 402 * @len: The length of the extect to attempt to map 403 * @get_block: The block mapping function for the fs 404 * 405 * Calls __generic_block_fiemap to map the inode, after taking 406 * the inode's mutex lock. 407 */ 408 409int generic_block_fiemap(struct inode *inode, 410 struct fiemap_extent_info *fieinfo, u64 start, 411 u64 len, get_block_t *get_block) 412{ 413 int ret; 414 mutex_lock(&inode->i_mutex); 415 ret = __generic_block_fiemap(inode, fieinfo, start, len, get_block); 416 mutex_unlock(&inode->i_mutex); 417 return ret; 418} 419EXPORT_SYMBOL(generic_block_fiemap); 420 421#endif /* CONFIG_BLOCK */ 422 423/* 424 * This provides compatibility with legacy XFS pre-allocation ioctls 425 * which predate the fallocate syscall. 426 * 427 * Only the l_start, l_len and l_whence fields of the 'struct space_resv' 428 * are used here, rest are ignored. 429 */ 430int ioctl_preallocate(struct file *filp, void __user *argp) 431{ 432 struct inode *inode = file_inode(filp); 433 struct space_resv sr; 434 435 if (copy_from_user(&sr, argp, sizeof(sr))) 436 return -EFAULT; 437 438 switch (sr.l_whence) { 439 case SEEK_SET: 440 break; 441 case SEEK_CUR: 442 sr.l_start += filp->f_pos; 443 break; 444 case SEEK_END: 445 sr.l_start += i_size_read(inode); 446 break; 447 default: 448 return -EINVAL; 449 } 450 451 return vfs_fallocate(filp, FALLOC_FL_KEEP_SIZE, sr.l_start, sr.l_len); 452} 453 454static int file_ioctl(struct file *filp, unsigned int cmd, 455 unsigned long arg) 456{ 457 struct inode *inode = file_inode(filp); 458 int __user *p = (int __user *)arg; 459 460 switch (cmd) { 461 case FIBMAP: 462 return ioctl_fibmap(filp, p); 463 case FIONREAD: 464 return put_user(i_size_read(inode) - filp->f_pos, p); 465 case FS_IOC_RESVSP: 466 case FS_IOC_RESVSP64: 467 return ioctl_preallocate(filp, p); 468 } 469 470 return vfs_ioctl(filp, cmd, arg); 471} 472 473static int ioctl_fionbio(struct file *filp, int __user *argp) 474{ 475 unsigned int flag; 476 int on, error; 477 478 error = get_user(on, argp); 479 if (error) 480 return error; 481 flag = O_NONBLOCK; 482#ifdef __sparc__ 483 /* SunOS compatibility item. */ 484 if (O_NONBLOCK != O_NDELAY) 485 flag |= O_NDELAY; 486#endif 487 spin_lock(&filp->f_lock); 488 if (on) 489 filp->f_flags |= flag; 490 else 491 filp->f_flags &= ~flag; 492 spin_unlock(&filp->f_lock); 493 return error; 494} 495 496static int ioctl_fioasync(unsigned int fd, struct file *filp, 497 int __user *argp) 498{ 499 unsigned int flag; 500 int on, error; 501 502 error = get_user(on, argp); 503 if (error) 504 return error; 505 flag = on ? FASYNC : 0; 506 507 /* Did FASYNC state change ? */ 508 if ((flag ^ filp->f_flags) & FASYNC) { 509 if (filp->f_op->fasync) 510 /* fasync() adjusts filp->f_flags */ 511 error = filp->f_op->fasync(fd, filp, on); 512 else 513 error = -ENOTTY; 514 } 515 return error < 0 ? error : 0; 516} 517 518static int ioctl_fsfreeze(struct file *filp) 519{ 520 struct super_block *sb = file_inode(filp)->i_sb; 521 522 if (!capable(CAP_SYS_ADMIN)) 523 return -EPERM; 524 525 /* If filesystem doesn't support freeze feature, return. */ 526 if (sb->s_op->freeze_fs == NULL && sb->s_op->freeze_super == NULL) 527 return -EOPNOTSUPP; 528 529 /* Freeze */ 530 if (sb->s_op->freeze_super) 531 return sb->s_op->freeze_super(sb); 532 return freeze_super(sb); 533} 534 535static int ioctl_fsthaw(struct file *filp) 536{ 537 struct super_block *sb = file_inode(filp)->i_sb; 538 539 if (!capable(CAP_SYS_ADMIN)) 540 return -EPERM; 541 542 /* Thaw */ 543 if (sb->s_op->thaw_super) 544 return sb->s_op->thaw_super(sb); 545 return thaw_super(sb); 546} 547 548/* 549 * When you add any new common ioctls to the switches above and below 550 * please update compat_sys_ioctl() too. 551 * 552 * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d. 553 * It's just a simple helper for sys_ioctl and compat_sys_ioctl. 554 */ 555int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, 556 unsigned long arg) 557{ 558 int error = 0; 559 int __user *argp = (int __user *)arg; 560 struct inode *inode = file_inode(filp); 561 562 switch (cmd) { 563 case FIOCLEX: 564 set_close_on_exec(fd, 1); 565 break; 566 567 case FIONCLEX: 568 set_close_on_exec(fd, 0); 569 break; 570 571 case FIONBIO: 572 error = ioctl_fionbio(filp, argp); 573 break; 574 575 case FIOASYNC: 576 error = ioctl_fioasync(fd, filp, argp); 577 break; 578 579 case FIOQSIZE: 580 if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode) || 581 S_ISLNK(inode->i_mode)) { 582 loff_t res = inode_get_bytes(inode); 583 error = copy_to_user(argp, &res, sizeof(res)) ? 584 -EFAULT : 0; 585 } else 586 error = -ENOTTY; 587 break; 588 589 case FIFREEZE: 590 error = ioctl_fsfreeze(filp); 591 break; 592 593 case FITHAW: 594 error = ioctl_fsthaw(filp); 595 break; 596 597 case FS_IOC_FIEMAP: 598 return ioctl_fiemap(filp, arg); 599 600 case FIGETBSZ: 601 return put_user(inode->i_sb->s_blocksize, argp); 602 603 default: 604 if (S_ISREG(inode->i_mode)) 605 error = file_ioctl(filp, cmd, arg); 606 else 607 error = vfs_ioctl(filp, cmd, arg); 608 break; 609 } 610 return error; 611} 612 613SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) 614{ 615 int error; 616 struct fd f = fdget(fd); 617 618 if (!f.file) 619 return -EBADF; 620 error = security_file_ioctl(f.file, cmd, arg); 621 if (!error) 622 error = do_vfs_ioctl(f.file, fd, cmd, arg); 623 fdput(f); 624 return error; 625} 626