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 */
vfs_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)35 static 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
ioctl_fibmap(struct file * filp,int __user * p)50 static 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)
fiemap_fill_next_extent(struct fiemap_extent_info * fieinfo,u64 logical,u64 phys,u64 len,u32 flags)85 int 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 }
122 EXPORT_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 */
fiemap_check_flags(struct fiemap_extent_info * fieinfo,u32 fs_flags)138 int 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 }
149 EXPORT_SYMBOL(fiemap_check_flags);
150
fiemap_check_ranges(struct super_block * sb,u64 start,u64 len,u64 * new_len)151 static 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
ioctl_fiemap(struct file * filp,unsigned long arg)173 static 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
logical_to_blk(struct inode * inode,loff_t offset)220 static inline sector_t logical_to_blk(struct inode *inode, loff_t offset)
221 {
222 return (offset >> inode->i_blkbits);
223 }
224
blk_to_logical(struct inode * inode,sector_t blk)225 static 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
__generic_block_fiemap(struct inode * inode,struct fiemap_extent_info * fieinfo,loff_t start,loff_t len,get_block_t * get_block)250 int __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 } while (1);
383
384 /* If ret is 1 then we just hit the end of the extent array */
385 if (ret == 1)
386 ret = 0;
387
388 return ret;
389 }
390 EXPORT_SYMBOL(__generic_block_fiemap);
391
392 /**
393 * generic_block_fiemap - FIEMAP for block based inodes
394 * @inode: The inode to map
395 * @fieinfo: The mapping information
396 * @start: The initial block to map
397 * @len: The length of the extect to attempt to map
398 * @get_block: The block mapping function for the fs
399 *
400 * Calls __generic_block_fiemap to map the inode, after taking
401 * the inode's mutex lock.
402 */
403
generic_block_fiemap(struct inode * inode,struct fiemap_extent_info * fieinfo,u64 start,u64 len,get_block_t * get_block)404 int generic_block_fiemap(struct inode *inode,
405 struct fiemap_extent_info *fieinfo, u64 start,
406 u64 len, get_block_t *get_block)
407 {
408 int ret;
409 mutex_lock(&inode->i_mutex);
410 ret = __generic_block_fiemap(inode, fieinfo, start, len, get_block);
411 mutex_unlock(&inode->i_mutex);
412 return ret;
413 }
414 EXPORT_SYMBOL(generic_block_fiemap);
415
416 #endif /* CONFIG_BLOCK */
417
418 /*
419 * This provides compatibility with legacy XFS pre-allocation ioctls
420 * which predate the fallocate syscall.
421 *
422 * Only the l_start, l_len and l_whence fields of the 'struct space_resv'
423 * are used here, rest are ignored.
424 */
ioctl_preallocate(struct file * filp,void __user * argp)425 int ioctl_preallocate(struct file *filp, void __user *argp)
426 {
427 struct inode *inode = file_inode(filp);
428 struct space_resv sr;
429
430 if (copy_from_user(&sr, argp, sizeof(sr)))
431 return -EFAULT;
432
433 switch (sr.l_whence) {
434 case SEEK_SET:
435 break;
436 case SEEK_CUR:
437 sr.l_start += filp->f_pos;
438 break;
439 case SEEK_END:
440 sr.l_start += i_size_read(inode);
441 break;
442 default:
443 return -EINVAL;
444 }
445
446 return do_fallocate(filp, FALLOC_FL_KEEP_SIZE, sr.l_start, sr.l_len);
447 }
448
file_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)449 static int file_ioctl(struct file *filp, unsigned int cmd,
450 unsigned long arg)
451 {
452 struct inode *inode = file_inode(filp);
453 int __user *p = (int __user *)arg;
454
455 switch (cmd) {
456 case FIBMAP:
457 return ioctl_fibmap(filp, p);
458 case FIONREAD:
459 return put_user(i_size_read(inode) - filp->f_pos, p);
460 case FS_IOC_RESVSP:
461 case FS_IOC_RESVSP64:
462 return ioctl_preallocate(filp, p);
463 }
464
465 return vfs_ioctl(filp, cmd, arg);
466 }
467
ioctl_fionbio(struct file * filp,int __user * argp)468 static int ioctl_fionbio(struct file *filp, int __user *argp)
469 {
470 unsigned int flag;
471 int on, error;
472
473 error = get_user(on, argp);
474 if (error)
475 return error;
476 flag = O_NONBLOCK;
477 #ifdef __sparc__
478 /* SunOS compatibility item. */
479 if (O_NONBLOCK != O_NDELAY)
480 flag |= O_NDELAY;
481 #endif
482 spin_lock(&filp->f_lock);
483 if (on)
484 filp->f_flags |= flag;
485 else
486 filp->f_flags &= ~flag;
487 spin_unlock(&filp->f_lock);
488 return error;
489 }
490
ioctl_fioasync(unsigned int fd,struct file * filp,int __user * argp)491 static int ioctl_fioasync(unsigned int fd, struct file *filp,
492 int __user *argp)
493 {
494 unsigned int flag;
495 int on, error;
496
497 error = get_user(on, argp);
498 if (error)
499 return error;
500 flag = on ? FASYNC : 0;
501
502 /* Did FASYNC state change ? */
503 if ((flag ^ filp->f_flags) & FASYNC) {
504 if (filp->f_op->fasync)
505 /* fasync() adjusts filp->f_flags */
506 error = filp->f_op->fasync(fd, filp, on);
507 else
508 error = -ENOTTY;
509 }
510 return error < 0 ? error : 0;
511 }
512
ioctl_fsfreeze(struct file * filp)513 static int ioctl_fsfreeze(struct file *filp)
514 {
515 struct super_block *sb = file_inode(filp)->i_sb;
516
517 if (!capable(CAP_SYS_ADMIN))
518 return -EPERM;
519
520 /* If filesystem doesn't support freeze feature, return. */
521 if (sb->s_op->freeze_fs == NULL)
522 return -EOPNOTSUPP;
523
524 /* Freeze */
525 return freeze_super(sb);
526 }
527
ioctl_fsthaw(struct file * filp)528 static int ioctl_fsthaw(struct file *filp)
529 {
530 struct super_block *sb = file_inode(filp)->i_sb;
531
532 if (!capable(CAP_SYS_ADMIN))
533 return -EPERM;
534
535 /* Thaw */
536 return thaw_super(sb);
537 }
538
539 /*
540 * When you add any new common ioctls to the switches above and below
541 * please update compat_sys_ioctl() too.
542 *
543 * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
544 * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
545 */
do_vfs_ioctl(struct file * filp,unsigned int fd,unsigned int cmd,unsigned long arg)546 int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
547 unsigned long arg)
548 {
549 int error = 0;
550 int __user *argp = (int __user *)arg;
551 struct inode *inode = file_inode(filp);
552
553 switch (cmd) {
554 case FIOCLEX:
555 set_close_on_exec(fd, 1);
556 break;
557
558 case FIONCLEX:
559 set_close_on_exec(fd, 0);
560 break;
561
562 case FIONBIO:
563 error = ioctl_fionbio(filp, argp);
564 break;
565
566 case FIOASYNC:
567 error = ioctl_fioasync(fd, filp, argp);
568 break;
569
570 case FIOQSIZE:
571 if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode) ||
572 S_ISLNK(inode->i_mode)) {
573 loff_t res = inode_get_bytes(inode);
574 error = copy_to_user(argp, &res, sizeof(res)) ?
575 -EFAULT : 0;
576 } else
577 error = -ENOTTY;
578 break;
579
580 case FIFREEZE:
581 error = ioctl_fsfreeze(filp);
582 break;
583
584 case FITHAW:
585 error = ioctl_fsthaw(filp);
586 break;
587
588 case FS_IOC_FIEMAP:
589 return ioctl_fiemap(filp, arg);
590
591 case FIGETBSZ:
592 return put_user(inode->i_sb->s_blocksize, argp);
593
594 default:
595 if (S_ISREG(inode->i_mode))
596 error = file_ioctl(filp, cmd, arg);
597 else
598 error = vfs_ioctl(filp, cmd, arg);
599 break;
600 }
601 return error;
602 }
603
SYSCALL_DEFINE3(ioctl,unsigned int,fd,unsigned int,cmd,unsigned long,arg)604 SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
605 {
606 int error;
607 struct fd f = fdget(fd);
608
609 if (!f.file)
610 return -EBADF;
611 error = security_file_ioctl(f.file, cmd, arg);
612 if (!error)
613 error = do_vfs_ioctl(f.file, fd, cmd, arg);
614 fdput(f);
615 return error;
616 }
617