ioctl.c 15.1 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1 2 3 4 5 6 7 8 9
/*
 *  linux/fs/ioctl.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <linux/syscalls.h>
#include <linux/mm.h>
#include <linux/smp_lock.h>
10
#include <linux/capability.h>
Linus Torvalds's avatar
Linus Torvalds committed
11 12 13 14
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/module.h>
15
#include <linux/uaccess.h>
16 17
#include <linux/writeback.h>
#include <linux/buffer_head.h>
Linus Torvalds's avatar
Linus Torvalds committed
18 19 20

#include <asm/ioctls.h>

Mark Fasheh's avatar
Mark Fasheh committed
21 22 23
/* So that the fiemap access checks can't overflow on 32 bit machines. */
#define FIEMAP_MAX_EXTENTS	(UINT_MAX / sizeof(struct fiemap_extent))

24 25
/**
 * vfs_ioctl - call filesystem specific ioctl methods
26 27 28
 * @filp:	open file to invoke ioctl method on
 * @cmd:	ioctl command to execute
 * @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 33 34 35
 * returns -ENOTTY.
 *
 * Returns 0 on success, -errno on error.
 */
Adrian Bunk's avatar
Adrian Bunk committed
36 37
static long vfs_ioctl(struct file *filp, unsigned int cmd,
		      unsigned long arg)
Linus Torvalds's avatar
Linus Torvalds committed
38 39 40 41 42 43 44 45 46 47 48
{
	int error = -ENOTTY;

	if (!filp->f_op)
		goto out;

	if (filp->f_op->unlocked_ioctl) {
		error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
		if (error == -ENOIOCTLCMD)
			error = -EINVAL;
		goto out;
49
	} else if (filp->f_op->ioctl) {
Linus Torvalds's avatar
Linus Torvalds committed
50
		lock_kernel();
51 52
		error = filp->f_op->ioctl(filp->f_path.dentry->d_inode,
					  filp, cmd, arg);
Linus Torvalds's avatar
Linus Torvalds committed
53 54 55 56 57 58 59
		unlock_kernel();
	}

 out:
	return error;
}

60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76
static int ioctl_fibmap(struct file *filp, int __user *p)
{
	struct address_space *mapping = filp->f_mapping;
	int res, block;

	/* do we support this mess? */
	if (!mapping->a_ops->bmap)
		return -EINVAL;
	if (!capable(CAP_SYS_RAWIO))
		return -EPERM;
	res = get_user(block, p);
	if (res)
		return res;
	res = mapping->a_ops->bmap(mapping, block);
	return put_user(res, p);
}

Mark Fasheh's avatar
Mark Fasheh committed
77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226
/**
 * fiemap_fill_next_extent - Fiemap helper function
 * @fieinfo:	Fiemap context passed into ->fiemap
 * @logical:	Extent logical start offset, in bytes
 * @phys:	Extent physical start offset, in bytes
 * @len:	Extent length, in bytes
 * @flags:	FIEMAP_EXTENT flags that describe this extent
 *
 * Called from file system ->fiemap callback. Will populate extent
 * info as passed in via arguments and copy to user memory. On
 * success, extent count on fieinfo is incremented.
 *
 * Returns 0 on success, -errno on error, 1 if this was the last
 * extent that will fit in user array.
 */
#define SET_UNKNOWN_FLAGS	(FIEMAP_EXTENT_DELALLOC)
#define SET_NO_UNMOUNTED_IO_FLAGS	(FIEMAP_EXTENT_DATA_ENCRYPTED)
#define SET_NOT_ALIGNED_FLAGS	(FIEMAP_EXTENT_DATA_TAIL|FIEMAP_EXTENT_DATA_INLINE)
int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical,
			    u64 phys, u64 len, u32 flags)
{
	struct fiemap_extent extent;
	struct fiemap_extent *dest = fieinfo->fi_extents_start;

	/* only count the extents */
	if (fieinfo->fi_extents_max == 0) {
		fieinfo->fi_extents_mapped++;
		return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
	}

	if (fieinfo->fi_extents_mapped >= fieinfo->fi_extents_max)
		return 1;

	if (flags & SET_UNKNOWN_FLAGS)
		flags |= FIEMAP_EXTENT_UNKNOWN;
	if (flags & SET_NO_UNMOUNTED_IO_FLAGS)
		flags |= FIEMAP_EXTENT_ENCODED;
	if (flags & SET_NOT_ALIGNED_FLAGS)
		flags |= FIEMAP_EXTENT_NOT_ALIGNED;

	memset(&extent, 0, sizeof(extent));
	extent.fe_logical = logical;
	extent.fe_physical = phys;
	extent.fe_length = len;
	extent.fe_flags = flags;

	dest += fieinfo->fi_extents_mapped;
	if (copy_to_user(dest, &extent, sizeof(extent)))
		return -EFAULT;

	fieinfo->fi_extents_mapped++;
	if (fieinfo->fi_extents_mapped == fieinfo->fi_extents_max)
		return 1;
	return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
}
EXPORT_SYMBOL(fiemap_fill_next_extent);

/**
 * fiemap_check_flags - check validity of requested flags for fiemap
 * @fieinfo:	Fiemap context passed into ->fiemap
 * @fs_flags:	Set of fiemap flags that the file system understands
 *
 * Called from file system ->fiemap callback. This will compute the
 * intersection of valid fiemap flags and those that the fs supports. That
 * value is then compared against the user supplied flags. In case of bad user
 * flags, the invalid values will be written into the fieinfo structure, and
 * -EBADR is returned, which tells ioctl_fiemap() to return those values to
 * userspace. For this reason, a return code of -EBADR should be preserved.
 *
 * Returns 0 on success, -EBADR on bad flags.
 */
int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags)
{
	u32 incompat_flags;

	incompat_flags = fieinfo->fi_flags & ~(FIEMAP_FLAGS_COMPAT & fs_flags);
	if (incompat_flags) {
		fieinfo->fi_flags = incompat_flags;
		return -EBADR;
	}
	return 0;
}
EXPORT_SYMBOL(fiemap_check_flags);

static int fiemap_check_ranges(struct super_block *sb,
			       u64 start, u64 len, u64 *new_len)
{
	*new_len = len;

	if (len == 0)
		return -EINVAL;

	if (start > sb->s_maxbytes)
		return -EFBIG;

	/*
	 * Shrink request scope to what the fs can actually handle.
	 */
	if ((len > sb->s_maxbytes) ||
	    (sb->s_maxbytes - len) < start)
		*new_len = sb->s_maxbytes - start;

	return 0;
}

static int ioctl_fiemap(struct file *filp, unsigned long arg)
{
	struct fiemap fiemap;
	struct fiemap_extent_info fieinfo = { 0, };
	struct inode *inode = filp->f_path.dentry->d_inode;
	struct super_block *sb = inode->i_sb;
	u64 len;
	int error;

	if (!inode->i_op->fiemap)
		return -EOPNOTSUPP;

	if (copy_from_user(&fiemap, (struct fiemap __user *)arg,
			   sizeof(struct fiemap)))
		return -EFAULT;

	if (fiemap.fm_extent_count > FIEMAP_MAX_EXTENTS)
		return -EINVAL;

	error = fiemap_check_ranges(sb, fiemap.fm_start, fiemap.fm_length,
				    &len);
	if (error)
		return error;

	fieinfo.fi_flags = fiemap.fm_flags;
	fieinfo.fi_extents_max = fiemap.fm_extent_count;
	fieinfo.fi_extents_start = (struct fiemap_extent *)(arg + sizeof(fiemap));

	if (fiemap.fm_extent_count != 0 &&
	    !access_ok(VERIFY_WRITE, fieinfo.fi_extents_start,
		       fieinfo.fi_extents_max * sizeof(struct fiemap_extent)))
		return -EFAULT;

	if (fieinfo.fi_flags & FIEMAP_FLAG_SYNC)
		filemap_write_and_wait(inode->i_mapping);

	error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start, len);
	fiemap.fm_flags = fieinfo.fi_flags;
	fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped;
	if (copy_to_user((char *)arg, &fiemap, sizeof(fiemap)))
		error = -EFAULT;

	return error;
}

227 228
#ifdef CONFIG_BLOCK

229 230 231
#define blk_to_logical(inode, blk) (blk << (inode)->i_blkbits)
#define logical_to_blk(inode, offset) (offset >> (inode)->i_blkbits);

232 233
/**
 * __generic_block_fiemap - FIEMAP for block based inodes (no locking)
234 235 236 237 238 239 240 241 242 243
 * @inode - the inode to map
 * @arg - the pointer to userspace where we copy everything to
 * @get_block - the fs's get_block function
 *
 * This does FIEMAP for block based inodes.  Basically it will just loop
 * through get_block until we hit the number of extents we want to map, or we
 * go past the end of the file and hit a hole.
 *
 * If it is possible to have data blocks beyond a hole past @inode->i_size, then
 * please do not use this function, it will stop at the first unmapped block
244 245 246 247
 * beyond i_size.
 *
 * If you use this function directly, you need to do your own locking. Use
 * generic_block_fiemap if you want the locking done for you.
248
 */
249 250 251 252

int __generic_block_fiemap(struct inode *inode,
			   struct fiemap_extent_info *fieinfo, u64 start,
			   u64 len, get_block_t *get_block)
253 254 255 256 257 258
{
	struct buffer_head tmp;
	unsigned int start_blk;
	long long length = 0, map_len = 0;
	u64 logical = 0, phys = 0, size = 0;
	u32 flags = FIEMAP_EXTENT_MERGED;
259
	int ret = 0, past_eof = 0, whole_file = 0;
260 261 262 263 264 265 266

	if ((ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC)))
		return ret;

	start_blk = logical_to_blk(inode, start);

	length = (long long)min_t(u64, len, i_size_read(inode));
267 268 269
	if (length < len)
		whole_file = 1;

270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285
	map_len = length;

	do {
		/*
		 * we set b_size to the total size we want so it will map as
		 * many contiguous blocks as possible at once
		 */
		memset(&tmp, 0, sizeof(struct buffer_head));
		tmp.b_size = map_len;

		ret = get_block(inode, start_blk, &tmp, 0);
		if (ret)
			break;

		/* HOLE */
		if (!buffer_mapped(&tmp)) {
286 287 288 289 290 291 292 293 294 295 296 297 298 299 300
			length -= blk_to_logical(inode, 1);
			start_blk++;

			/*
			 * we want to handle the case where there is an
			 * allocated block at the front of the file, and then
			 * nothing but holes up to the end of the file properly,
			 * to make sure that extent at the front gets properly
			 * marked with FIEMAP_EXTENT_LAST
			 */
			if (!past_eof &&
			    blk_to_logical(inode, start_blk) >=
			    blk_to_logical(inode, 0)+i_size_read(inode))
				past_eof = 1;

301 302 303 304
			/*
			 * first hole after going past the EOF, this is our
			 * last extent
			 */
305
			if (past_eof && size) {
306 307 308 309 310 311 312 313
				flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST;
				ret = fiemap_fill_next_extent(fieinfo, logical,
							      phys, size,
							      flags);
				break;
			}

			/* if we have holes up to/past EOF then we're done */
314
			if (length <= 0 || past_eof)
315 316
				break;
		} else {
317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343
			/*
			 * we have gone over the length of what we wanted to
			 * map, and it wasn't the entire file, so add the extent
			 * we got last time and exit.
			 *
			 * This is for the case where say we want to map all the
			 * way up to the second to the last block in a file, but
			 * the last block is a hole, making the second to last
			 * block FIEMAP_EXTENT_LAST.  In this case we want to
			 * see if there is a hole after the second to last block
			 * so we can mark it properly.  If we found data after
			 * we exceeded the length we were requesting, then we
			 * are good to go, just add the extent to the fieinfo
			 * and break
			 */
			if (length <= 0 && !whole_file) {
				ret = fiemap_fill_next_extent(fieinfo, logical,
							      phys, size,
							      flags);
				break;
			}

			/*
			 * if size != 0 then we know we already have an extent
			 * to add, so add it.
			 */
			if (size) {
344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359
				ret = fiemap_fill_next_extent(fieinfo, logical,
							      phys, size,
							      flags);
				if (ret)
					break;
			}

			logical = blk_to_logical(inode, start_blk);
			phys = blk_to_logical(inode, tmp.b_blocknr);
			size = tmp.b_size;
			flags = FIEMAP_EXTENT_MERGED;

			length -= tmp.b_size;
			start_blk += logical_to_blk(inode, size);

			/*
360 361 362
			 * If we are past the EOF, then we need to make sure as
			 * soon as we find a hole that the last extent we found
			 * is marked with FIEMAP_EXTENT_LAST
363
			 */
364 365 366 367
			if (!past_eof &&
			    logical+size >=
			    blk_to_logical(inode, 0)+i_size_read(inode))
				past_eof = 1;
368 369 370 371 372 373 374 375 376 377
		}
		cond_resched();
	} while (1);

	/* if ret is 1 then we just hit the end of the extent array */
	if (ret == 1)
		ret = 0;

	return ret;
}
378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401
EXPORT_SYMBOL(__generic_block_fiemap);

/**
 * generic_block_fiemap - FIEMAP for block based inodes
 * @inode: The inode to map
 * @fieinfo: The mapping information
 * @start: The initial block to map
 * @len: The length of the extect to attempt to map
 * @get_block: The block mapping function for the fs
 *
 * Calls __generic_block_fiemap to map the inode, after taking
 * the inode's mutex lock.
 */

int generic_block_fiemap(struct inode *inode,
			 struct fiemap_extent_info *fieinfo, u64 start,
			 u64 len, get_block_t *get_block)
{
	int ret;
	mutex_lock(&inode->i_mutex);
	ret = __generic_block_fiemap(inode, fieinfo, start, len, get_block);
	mutex_unlock(&inode->i_mutex);
	return ret;
}
402 403
EXPORT_SYMBOL(generic_block_fiemap);

404 405
#endif  /*  CONFIG_BLOCK  */

Linus Torvalds's avatar
Linus Torvalds committed
406 407 408
static int file_ioctl(struct file *filp, unsigned int cmd,
		unsigned long arg)
{
409
	struct inode *inode = filp->f_path.dentry->d_inode;
Linus Torvalds's avatar
Linus Torvalds committed
410 411 412
	int __user *p = (int __user *)arg;

	switch (cmd) {
413
	case FIBMAP:
414
		return ioctl_fibmap(filp, p);
415 416
	case FIONREAD:
		return put_user(i_size_read(inode) - filp->f_pos, p);
Linus Torvalds's avatar
Linus Torvalds committed
417 418
	}

419
	return vfs_ioctl(filp, cmd, arg);
Linus Torvalds's avatar
Linus Torvalds committed
420 421
}

422 423 424 425 426 427 428 429 430 431 432 433 434 435
static int ioctl_fionbio(struct file *filp, int __user *argp)
{
	unsigned int flag;
	int on, error;

	error = get_user(on, argp);
	if (error)
		return error;
	flag = O_NONBLOCK;
#ifdef __sparc__
	/* SunOS compatibility item. */
	if (O_NONBLOCK != O_NDELAY)
		flag |= O_NDELAY;
#endif
436
	spin_lock(&filp->f_lock);
437 438 439 440
	if (on)
		filp->f_flags |= flag;
	else
		filp->f_flags &= ~flag;
441
	spin_unlock(&filp->f_lock);
442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457
	return error;
}

static int ioctl_fioasync(unsigned int fd, struct file *filp,
			  int __user *argp)
{
	unsigned int flag;
	int on, error;

	error = get_user(on, argp);
	if (error)
		return error;
	flag = on ? FASYNC : 0;

	/* Did FASYNC state change ? */
	if ((flag ^ filp->f_flags) & FASYNC) {
458
		if (filp->f_op && filp->f_op->fasync)
459
			/* fasync() adjusts filp->f_flags */
460
			error = filp->f_op->fasync(fd, filp, on);
461
		else
462 463
			error = -ENOTTY;
	}
464
	return error < 0 ? error : 0;
465 466
}

467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503
static int ioctl_fsfreeze(struct file *filp)
{
	struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	/* If filesystem doesn't support freeze feature, return. */
	if (sb->s_op->freeze_fs == NULL)
		return -EOPNOTSUPP;

	/* If a blockdevice-backed filesystem isn't specified, return. */
	if (sb->s_bdev == NULL)
		return -EINVAL;

	/* Freeze */
	sb = freeze_bdev(sb->s_bdev);
	if (IS_ERR(sb))
		return PTR_ERR(sb);
	return 0;
}

static int ioctl_fsthaw(struct file *filp)
{
	struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	/* If a blockdevice-backed filesystem isn't specified, return EINVAL. */
	if (sb->s_bdev == NULL)
		return -EINVAL;

	/* Thaw */
	return thaw_bdev(sb->s_bdev, sb);
}

Linus Torvalds's avatar
Linus Torvalds committed
504 505 506 507
/*
 * When you add any new common ioctls to the switches above and below
 * please update compat_sys_ioctl() too.
 *
508
 * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
Linus Torvalds's avatar
Linus Torvalds committed
509 510
 * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
 */
511 512
int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
	     unsigned long arg)
Linus Torvalds's avatar
Linus Torvalds committed
513
{
514 515
	int error = 0;
	int __user *argp = (int __user *)arg;
Linus Torvalds's avatar
Linus Torvalds committed
516 517

	switch (cmd) {
518 519 520
	case FIOCLEX:
		set_close_on_exec(fd, 1);
		break;
Linus Torvalds's avatar
Linus Torvalds committed
521

522 523 524
	case FIONCLEX:
		set_close_on_exec(fd, 0);
		break;
Linus Torvalds's avatar
Linus Torvalds committed
525

526
	case FIONBIO:
527
		error = ioctl_fionbio(filp, argp);
528 529 530
		break;

	case FIOASYNC:
531
		error = ioctl_fioasync(fd, filp, argp);
532 533 534 535 536 537 538 539 540 541 542 543 544
		break;

	case FIOQSIZE:
		if (S_ISDIR(filp->f_path.dentry->d_inode->i_mode) ||
		    S_ISREG(filp->f_path.dentry->d_inode->i_mode) ||
		    S_ISLNK(filp->f_path.dentry->d_inode->i_mode)) {
			loff_t res =
				inode_get_bytes(filp->f_path.dentry->d_inode);
			error = copy_to_user((loff_t __user *)arg, &res,
					     sizeof(res)) ? -EFAULT : 0;
		} else
			error = -ENOTTY;
		break;
545 546 547 548 549 550 551 552 553

	case FIFREEZE:
		error = ioctl_fsfreeze(filp);
		break;

	case FITHAW:
		error = ioctl_fsthaw(filp);
		break;

554 555 556 557 558 559 560 561 562 563
	case FS_IOC_FIEMAP:
		return ioctl_fiemap(filp, arg);

	case FIGETBSZ:
	{
		struct inode *inode = filp->f_path.dentry->d_inode;
		int __user *p = (int __user *)arg;
		return put_user(inode->i_sb->s_blocksize, p);
	}

564 565 566 567
	default:
		if (S_ISREG(filp->f_path.dentry->d_inode->i_mode))
			error = file_ioctl(filp, cmd, arg);
		else
568
			error = vfs_ioctl(filp, cmd, arg);
569
		break;
Linus Torvalds's avatar
Linus Torvalds committed
570 571 572 573
	}
	return error;
}

574
SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
Linus Torvalds's avatar
Linus Torvalds committed
575
{
576
	struct file *filp;
Linus Torvalds's avatar
Linus Torvalds committed
577 578 579 580 581 582 583 584 585 586 587
	int error = -EBADF;
	int fput_needed;

	filp = fget_light(fd, &fput_needed);
	if (!filp)
		goto out;

	error = security_file_ioctl(filp, cmd, arg);
	if (error)
		goto out_fput;

588
	error = do_vfs_ioctl(filp, fd, cmd, arg);
Linus Torvalds's avatar
Linus Torvalds committed
589 590 591 592 593
 out_fput:
	fput_light(filp, fput_needed);
 out:
	return error;
}