Root/fs/ioctl.c

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#include <linux/falloc.h>
19
20#include <asm/ioctls.h>
21
22/* So that the fiemap access checks can't overflow on 32 bit machines. */
23#define FIEMAP_MAX_EXTENTS (UINT_MAX / sizeof(struct fiemap_extent))
24
25/**
26 * vfs_ioctl - call filesystem specific ioctl methods
27 * @filp: open file to invoke ioctl method on
28 * @cmd: ioctl command to execute
29 * @arg: command-specific argument for ioctl
30 *
31 * Invokes filesystem specific ->unlocked_ioctl, if one exists; otherwise
32 * invokes filesystem specific ->ioctl method. If neither method exists,
33 * returns -ENOTTY.
34 *
35 * Returns 0 on success, -errno on error.
36 */
37static long vfs_ioctl(struct file *filp, unsigned int cmd,
38              unsigned long arg)
39{
40    int error = -ENOTTY;
41
42    if (!filp->f_op)
43        goto out;
44
45    if (filp->f_op->unlocked_ioctl) {
46        error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
47        if (error == -ENOIOCTLCMD)
48            error = -EINVAL;
49        goto out;
50    } else if (filp->f_op->ioctl) {
51        lock_kernel();
52        error = filp->f_op->ioctl(filp->f_path.dentry->d_inode,
53                      filp, cmd, arg);
54        unlock_kernel();
55    }
56
57 out:
58    return error;
59}
60
61static int ioctl_fibmap(struct file *filp, int __user *p)
62{
63    struct address_space *mapping = filp->f_mapping;
64    int res, block;
65
66    /* do we support this mess? */
67    if (!mapping->a_ops->bmap)
68        return -EINVAL;
69    if (!capable(CAP_SYS_RAWIO))
70        return -EPERM;
71    res = get_user(block, p);
72    if (res)
73        return res;
74    res = mapping->a_ops->bmap(mapping, block);
75    return put_user(res, p);
76}
77
78/**
79 * fiemap_fill_next_extent - Fiemap helper function
80 * @fieinfo: Fiemap context passed into ->fiemap
81 * @logical: Extent logical start offset, in bytes
82 * @phys: Extent physical start offset, in bytes
83 * @len: Extent length, in bytes
84 * @flags: FIEMAP_EXTENT flags that describe this extent
85 *
86 * Called from file system ->fiemap callback. Will populate extent
87 * info as passed in via arguments and copy to user memory. On
88 * success, extent count on fieinfo is incremented.
89 *
90 * Returns 0 on success, -errno on error, 1 if this was the last
91 * extent that will fit in user array.
92 */
93#define SET_UNKNOWN_FLAGS (FIEMAP_EXTENT_DELALLOC)
94#define SET_NO_UNMOUNTED_IO_FLAGS (FIEMAP_EXTENT_DATA_ENCRYPTED)
95#define SET_NOT_ALIGNED_FLAGS (FIEMAP_EXTENT_DATA_TAIL|FIEMAP_EXTENT_DATA_INLINE)
96int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical,
97                u64 phys, u64 len, u32 flags)
98{
99    struct fiemap_extent extent;
100    struct fiemap_extent *dest = fieinfo->fi_extents_start;
101
102    /* only count the extents */
103    if (fieinfo->fi_extents_max == 0) {
104        fieinfo->fi_extents_mapped++;
105        return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
106    }
107
108    if (fieinfo->fi_extents_mapped >= fieinfo->fi_extents_max)
109        return 1;
110
111    if (flags & SET_UNKNOWN_FLAGS)
112        flags |= FIEMAP_EXTENT_UNKNOWN;
113    if (flags & SET_NO_UNMOUNTED_IO_FLAGS)
114        flags |= FIEMAP_EXTENT_ENCODED;
115    if (flags & SET_NOT_ALIGNED_FLAGS)
116        flags |= FIEMAP_EXTENT_NOT_ALIGNED;
117
118    memset(&extent, 0, sizeof(extent));
119    extent.fe_logical = logical;
120    extent.fe_physical = phys;
121    extent.fe_length = len;
122    extent.fe_flags = flags;
123
124    dest += fieinfo->fi_extents_mapped;
125    if (copy_to_user(dest, &extent, sizeof(extent)))
126        return -EFAULT;
127
128    fieinfo->fi_extents_mapped++;
129    if (fieinfo->fi_extents_mapped == fieinfo->fi_extents_max)
130        return 1;
131    return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
132}
133EXPORT_SYMBOL(fiemap_fill_next_extent);
134
135/**
136 * fiemap_check_flags - check validity of requested flags for fiemap
137 * @fieinfo: Fiemap context passed into ->fiemap
138 * @fs_flags: Set of fiemap flags that the file system understands
139 *
140 * Called from file system ->fiemap callback. This will compute the
141 * intersection of valid fiemap flags and those that the fs supports. That
142 * value is then compared against the user supplied flags. In case of bad user
143 * flags, the invalid values will be written into the fieinfo structure, and
144 * -EBADR is returned, which tells ioctl_fiemap() to return those values to
145 * userspace. For this reason, a return code of -EBADR should be preserved.
146 *
147 * Returns 0 on success, -EBADR on bad flags.
148 */
149int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags)
150{
151    u32 incompat_flags;
152
153    incompat_flags = fieinfo->fi_flags & ~(FIEMAP_FLAGS_COMPAT & fs_flags);
154    if (incompat_flags) {
155        fieinfo->fi_flags = incompat_flags;
156        return -EBADR;
157    }
158    return 0;
159}
160EXPORT_SYMBOL(fiemap_check_flags);
161
162static int fiemap_check_ranges(struct super_block *sb,
163                   u64 start, u64 len, u64 *new_len)
164{
165    u64 maxbytes = (u64) sb->s_maxbytes;
166
167    *new_len = len;
168
169    if (len == 0)
170        return -EINVAL;
171
172    if (start > maxbytes)
173        return -EFBIG;
174
175    /*
176     * Shrink request scope to what the fs can actually handle.
177     */
178    if (len > maxbytes || (maxbytes - len) < start)
179        *new_len = maxbytes - start;
180
181    return 0;
182}
183
184static 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
231static inline sector_t logical_to_blk(struct inode *inode, loff_t offset)
232{
233    return (offset >> inode->i_blkbits);
234}
235
236static inline loff_t blk_to_logical(struct inode *inode, sector_t blk)
237{
238    return (blk << inode->i_blkbits);
239}
240
241/**
242 * __generic_block_fiemap - FIEMAP for block based inodes (no locking)
243 * @inode: the inode to map
244 * @fieinfo: the fiemap info struct that will be passed back to userspace
245 * @start: where to start mapping in the inode
246 * @len: how much space to map
247 * @get_block: the fs's get_block function
248 *
249 * This does FIEMAP for block based inodes. Basically it will just loop
250 * through get_block until we hit the number of extents we want to map, or we
251 * go past the end of the file and hit a hole.
252 *
253 * If it is possible to have data blocks beyond a hole past @inode->i_size, then
254 * please do not use this function, it will stop at the first unmapped block
255 * beyond i_size.
256 *
257 * If you use this function directly, you need to do your own locking. Use
258 * generic_block_fiemap if you want the locking done for you.
259 */
260
261int __generic_block_fiemap(struct inode *inode,
262               struct fiemap_extent_info *fieinfo, loff_t start,
263               loff_t len, get_block_t *get_block)
264{
265    struct buffer_head map_bh;
266    sector_t start_blk, last_blk;
267    loff_t isize = i_size_read(inode);
268    u64 logical = 0, phys = 0, size = 0;
269    u32 flags = FIEMAP_EXTENT_MERGED;
270    bool past_eof = false, whole_file = false;
271    int ret = 0;
272
273    ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
274    if (ret)
275        return ret;
276
277    /*
278     * Either the i_mutex or other appropriate locking needs to be held
279     * since we expect isize to not change at all through the duration of
280     * this call.
281     */
282    if (len >= isize) {
283        whole_file = true;
284        len = isize;
285    }
286
287    start_blk = logical_to_blk(inode, start);
288    last_blk = logical_to_blk(inode, start + len - 1);
289
290    do {
291        /*
292         * we set b_size to the total size we want so it will map as
293         * many contiguous blocks as possible at once
294         */
295        memset(&map_bh, 0, sizeof(struct buffer_head));
296        map_bh.b_size = len;
297
298        ret = get_block(inode, start_blk, &map_bh, 0);
299        if (ret)
300            break;
301
302        /* HOLE */
303        if (!buffer_mapped(&map_bh)) {
304            start_blk++;
305
306            /*
307             * We want to handle the case where there is an
308             * allocated block at the front of the file, and then
309             * nothing but holes up to the end of the file properly,
310             * to make sure that extent at the front gets properly
311             * marked with FIEMAP_EXTENT_LAST
312             */
313            if (!past_eof &&
314                blk_to_logical(inode, start_blk) >= isize)
315                past_eof = 1;
316
317            /*
318             * First hole after going past the EOF, this is our
319             * last extent
320             */
321            if (past_eof && size) {
322                flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST;
323                ret = fiemap_fill_next_extent(fieinfo, logical,
324                                  phys, size,
325                                  flags);
326            } else if (size) {
327                ret = fiemap_fill_next_extent(fieinfo, logical,
328                                  phys, size, flags);
329                size = 0;
330            }
331
332            /* if we have holes up to/past EOF then we're done */
333            if (start_blk > last_blk || past_eof || ret)
334                break;
335        } else {
336            /*
337             * We have gone over the length of what we wanted to
338             * map, and it wasn't the entire file, so add the extent
339             * we got last time and exit.
340             *
341             * This is for the case where say we want to map all the
342             * way up to the second to the last block in a file, but
343             * the last block is a hole, making the second to last
344             * block FIEMAP_EXTENT_LAST. In this case we want to
345             * see if there is a hole after the second to last block
346             * so we can mark it properly. If we found data after
347             * we exceeded the length we were requesting, then we
348             * are good to go, just add the extent to the fieinfo
349             * and break
350             */
351            if (start_blk > last_blk && !whole_file) {
352                ret = fiemap_fill_next_extent(fieinfo, logical,
353                                  phys, size,
354                                  flags);
355                break;
356            }
357
358            /*
359             * if size != 0 then we know we already have an extent
360             * to add, so add it.
361             */
362            if (size) {
363                ret = fiemap_fill_next_extent(fieinfo, logical,
364                                  phys, size,
365                                  flags);
366                if (ret)
367                    break;
368            }
369
370            logical = blk_to_logical(inode, start_blk);
371            phys = blk_to_logical(inode, map_bh.b_blocknr);
372            size = map_bh.b_size;
373            flags = FIEMAP_EXTENT_MERGED;
374
375            start_blk += logical_to_blk(inode, size);
376
377            /*
378             * If we are past the EOF, then we need to make sure as
379             * soon as we find a hole that the last extent we found
380             * is marked with FIEMAP_EXTENT_LAST
381             */
382            if (!past_eof && logical + size >= isize)
383                past_eof = true;
384        }
385        cond_resched();
386    } while (1);
387
388    /* If ret is 1 then we just hit the end of the extent array */
389    if (ret == 1)
390        ret = 0;
391
392    return ret;
393}
394EXPORT_SYMBOL(__generic_block_fiemap);
395
396/**
397 * generic_block_fiemap - FIEMAP for block based inodes
398 * @inode: The inode to map
399 * @fieinfo: The mapping information
400 * @start: The initial block to map
401 * @len: The length of the extect to attempt to map
402 * @get_block: The block mapping function for the fs
403 *
404 * Calls __generic_block_fiemap to map the inode, after taking
405 * the inode's mutex lock.
406 */
407
408int generic_block_fiemap(struct inode *inode,
409             struct fiemap_extent_info *fieinfo, u64 start,
410             u64 len, get_block_t *get_block)
411{
412    int ret;
413    mutex_lock(&inode->i_mutex);
414    ret = __generic_block_fiemap(inode, fieinfo, start, len, get_block);
415    mutex_unlock(&inode->i_mutex);
416    return ret;
417}
418EXPORT_SYMBOL(generic_block_fiemap);
419
420#endif /* CONFIG_BLOCK */
421
422/*
423 * This provides compatibility with legacy XFS pre-allocation ioctls
424 * which predate the fallocate syscall.
425 *
426 * Only the l_start, l_len and l_whence fields of the 'struct space_resv'
427 * are used here, rest are ignored.
428 */
429int ioctl_preallocate(struct file *filp, void __user *argp)
430{
431    struct inode *inode = filp->f_path.dentry->d_inode;
432    struct space_resv sr;
433
434    if (copy_from_user(&sr, argp, sizeof(sr)))
435        return -EFAULT;
436
437    switch (sr.l_whence) {
438    case SEEK_SET:
439        break;
440    case SEEK_CUR:
441        sr.l_start += filp->f_pos;
442        break;
443    case SEEK_END:
444        sr.l_start += i_size_read(inode);
445        break;
446    default:
447        return -EINVAL;
448    }
449
450    return do_fallocate(filp, FALLOC_FL_KEEP_SIZE, sr.l_start, sr.l_len);
451}
452
453static int file_ioctl(struct file *filp, unsigned int cmd,
454        unsigned long arg)
455{
456    struct inode *inode = filp->f_path.dentry->d_inode;
457    int __user *p = (int __user *)arg;
458
459    switch (cmd) {
460    case FIBMAP:
461        return ioctl_fibmap(filp, p);
462    case FIONREAD:
463        return put_user(i_size_read(inode) - filp->f_pos, p);
464    case FS_IOC_RESVSP:
465    case FS_IOC_RESVSP64:
466        return ioctl_preallocate(filp, p);
467    }
468
469    return vfs_ioctl(filp, cmd, arg);
470}
471
472static int ioctl_fionbio(struct file *filp, int __user *argp)
473{
474    unsigned int flag;
475    int on, error;
476
477    error = get_user(on, argp);
478    if (error)
479        return error;
480    flag = O_NONBLOCK;
481#ifdef __sparc__
482    /* SunOS compatibility item. */
483    if (O_NONBLOCK != O_NDELAY)
484        flag |= O_NDELAY;
485#endif
486    spin_lock(&filp->f_lock);
487    if (on)
488        filp->f_flags |= flag;
489    else
490        filp->f_flags &= ~flag;
491    spin_unlock(&filp->f_lock);
492    return error;
493}
494
495static int ioctl_fioasync(unsigned int fd, struct file *filp,
496              int __user *argp)
497{
498    unsigned int flag;
499    int on, error;
500
501    error = get_user(on, argp);
502    if (error)
503        return error;
504    flag = on ? FASYNC : 0;
505
506    /* Did FASYNC state change ? */
507    if ((flag ^ filp->f_flags) & FASYNC) {
508        if (filp->f_op && filp->f_op->fasync)
509            /* fasync() adjusts filp->f_flags */
510            error = filp->f_op->fasync(fd, filp, on);
511        else
512            error = -ENOTTY;
513    }
514    return error < 0 ? error : 0;
515}
516
517static int ioctl_fsfreeze(struct file *filp)
518{
519    struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
520
521    if (!capable(CAP_SYS_ADMIN))
522        return -EPERM;
523
524    /* If filesystem doesn't support freeze feature, return. */
525    if (sb->s_op->freeze_fs == NULL)
526        return -EOPNOTSUPP;
527
528    /* If a blockdevice-backed filesystem isn't specified, return. */
529    if (sb->s_bdev == NULL)
530        return -EINVAL;
531
532    /* Freeze */
533    sb = freeze_bdev(sb->s_bdev);
534    if (IS_ERR(sb))
535        return PTR_ERR(sb);
536    return 0;
537}
538
539static int ioctl_fsthaw(struct file *filp)
540{
541    struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
542
543    if (!capable(CAP_SYS_ADMIN))
544        return -EPERM;
545
546    /* If a blockdevice-backed filesystem isn't specified, return EINVAL. */
547    if (sb->s_bdev == NULL)
548        return -EINVAL;
549
550    /* Thaw */
551    return thaw_bdev(sb->s_bdev, sb);
552}
553
554/*
555 * When you add any new common ioctls to the switches above and below
556 * please update compat_sys_ioctl() too.
557 *
558 * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
559 * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
560 */
561int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
562         unsigned long arg)
563{
564    int error = 0;
565    int __user *argp = (int __user *)arg;
566
567    switch (cmd) {
568    case FIOCLEX:
569        set_close_on_exec(fd, 1);
570        break;
571
572    case FIONCLEX:
573        set_close_on_exec(fd, 0);
574        break;
575
576    case FIONBIO:
577        error = ioctl_fionbio(filp, argp);
578        break;
579
580    case FIOASYNC:
581        error = ioctl_fioasync(fd, filp, argp);
582        break;
583
584    case FIOQSIZE:
585        if (S_ISDIR(filp->f_path.dentry->d_inode->i_mode) ||
586            S_ISREG(filp->f_path.dentry->d_inode->i_mode) ||
587            S_ISLNK(filp->f_path.dentry->d_inode->i_mode)) {
588            loff_t res =
589                inode_get_bytes(filp->f_path.dentry->d_inode);
590            error = copy_to_user((loff_t __user *)arg, &res,
591                         sizeof(res)) ? -EFAULT : 0;
592        } else
593            error = -ENOTTY;
594        break;
595
596    case FIFREEZE:
597        error = ioctl_fsfreeze(filp);
598        break;
599
600    case FITHAW:
601        error = ioctl_fsthaw(filp);
602        break;
603
604    case FS_IOC_FIEMAP:
605        return ioctl_fiemap(filp, arg);
606
607    case FIGETBSZ:
608    {
609        struct inode *inode = filp->f_path.dentry->d_inode;
610        int __user *p = (int __user *)arg;
611        return put_user(inode->i_sb->s_blocksize, p);
612    }
613
614    default:
615        if (S_ISREG(filp->f_path.dentry->d_inode->i_mode))
616            error = file_ioctl(filp, cmd, arg);
617        else
618            error = vfs_ioctl(filp, cmd, arg);
619        break;
620    }
621    return error;
622}
623
624SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
625{
626    struct file *filp;
627    int error = -EBADF;
628    int fput_needed;
629
630    filp = fget_light(fd, &fput_needed);
631    if (!filp)
632        goto out;
633
634    error = security_file_ioctl(filp, cmd, arg);
635    if (error)
636        goto out_fput;
637
638    error = do_vfs_ioctl(filp, fd, cmd, arg);
639 out_fput:
640    fput_light(filp, fput_needed);
641 out:
642    return error;
643}
644

Archive Download this file

Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive