/*

* linux/fs/ioctl.c

*

* Copyright (C) 1991, 1992 Linus Torvalds

*/

#include <linux/syscalls.h>

#include <linux/mm.h>

#include <linux/smp_lock.h>

#include <linux/capability.h>

#include <linux/file.h>

#include <linux/fs.h>

#include <linux/security.h>

#include <linux/module.h>

#include <linux/uaccess.h>

#include <linux/writeback.h>

#include <linux/buffer_head.h>

#include <linux/falloc.h>

#include <asm/ioctls.h>

/* So that the fiemap access checks can't overflow on 32 bit machines. */

#define FIEMAP_MAX_EXTENTS (UINT_MAX / sizeof(struct fiemap_extent))

/**

* vfs_ioctl - call filesystem specific ioctl methods

* @filp: open file to invoke ioctl method on

* @cmd: ioctl command to execute

* @arg: command-specific argument for ioctl

*

* Invokes filesystem specific ->unlocked_ioctl, if one exists; otherwise

* invokes filesystem specific ->ioctl method. If neither method exists,

* returns -ENOTTY.

*

* Returns 0 on success, -errno on error.

*/

static long vfs_ioctl(struct file *filp, unsigned int cmd,

unsigned long arg)

{

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;

} else if (filp->f_op->ioctl) {

lock_kernel();

error = filp->f_op->ioctl(filp->f_path.dentry->d_inode,

filp, cmd, arg);

unlock_kernel();

}

out:

return error;

}

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);

}

/**

* 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)

{

u64 maxbytes = (u64) sb->s_maxbytes;

*new_len = len;

if (len == 0)

return -EINVAL;

if (start > maxbytes)

return -EFBIG;

/*

* Shrink request scope to what the fs can actually handle.

*/

if (len > maxbytes || (maxbytes - len) < start)

*new_len = 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;

}

#ifdef CONFIG_BLOCK

static inline sector_t logical_to_blk(struct inode *inode, loff_t offset)

{

return (offset >> inode->i_blkbits);

}

static inline loff_t blk_to_logical(struct inode *inode, sector_t blk)

{

return (blk << inode->i_blkbits);

}

/**

* __generic_block_fiemap - FIEMAP for block based inodes (no locking)

* @inode: the inode to map

* @fieinfo: the fiemap info struct that will be passed back to userspace

* @start: where to start mapping in the inode

* @len: how much space to map

* @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

* 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.

*/

int __generic_block_fiemap(struct inode *inode,

struct fiemap_extent_info *fieinfo, loff_t start,

loff_t len, get_block_t *get_block)

{

struct buffer_head map_bh;

sector_t start_blk, last_blk;

loff_t isize = i_size_read(inode);

u64 logical = 0, phys = 0, size = 0;

u32 flags = FIEMAP_EXTENT_MERGED;

bool past_eof = false, whole_file = false;

int ret = 0;

ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);

if (ret)

return ret;

/*

* Either the i_mutex or other appropriate locking needs to be held

* since we expect isize to not change at all through the duration of

* this call.

*/

if (len >= isize) {

whole_file = true;

len = isize;

}

/*

* Some filesystems can't deal with being asked to map less than

* blocksize, so make sure our len is at least block length.

*/

if (logical_to_blk(inode, len) == 0)

len = blk_to_logical(inode, 1);

start_blk = logical_to_blk(inode, start);

last_blk = logical_to_blk(inode, start + len - 1);

do {

/*

* we set b_size to the total size we want so it will map as

* many contiguous blocks as possible at once

*/

memset(&map_bh, 0, sizeof(struct buffer_head));

map_bh.b_size = len;

ret = get_block(inode, start_blk, &map_bh, 0);

if (ret)

break;

/* HOLE */

if (!buffer_mapped(&map_bh)) {

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) >= isize)

past_eof = 1;

/*

* First hole after going past the EOF, this is our

* last extent

*/

if (past_eof && size) {

flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST;

ret = fiemap_fill_next_extent(fieinfo, logical,

phys, size,

flags);

} else if (size) {

ret = fiemap_fill_next_extent(fieinfo, logical,

phys, size, flags);

size = 0;

}

/* if we have holes up to/past EOF then we're done */

if (start_blk > last_blk || past_eof || ret)

break;

} else {

/*

* 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 (start_blk > last_blk && !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) {

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, map_bh.b_blocknr);

size = map_bh.b_size;

flags = FIEMAP_EXTENT_MERGED;

start_blk += logical_to_blk(inode, size);

/*

* 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

*/

if (!past_eof && logical + size >= isize)

past_eof = true;

}

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;

}

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;

}

EXPORT_SYMBOL(generic_block_fiemap);

#endif /* CONFIG_BLOCK */

/*

* This provides compatibility with legacy XFS pre-allocation ioctls

* which predate the fallocate syscall.

*

* Only the l_start, l_len and l_whence fields of the 'struct space_resv'

* are used here, rest are ignored.

*/

int ioctl_preallocate(struct file *filp, void __user *argp)

{

struct inode *inode = filp->f_path.dentry->d_inode;

struct space_resv sr;

if (copy_from_user(&sr, argp, sizeof(sr)))

return -EFAULT;

switch (sr.l_whence) {

case SEEK_SET:

break;

case SEEK_CUR:

sr.l_start += filp->f_pos;

break;

case SEEK_END:

sr.l_start += i_size_read(inode);

break;

default:

return -EINVAL;

}

return do_fallocate(filp, FALLOC_FL_KEEP_SIZE, sr.l_start, sr.l_len);

}

static int file_ioctl(struct file *filp, unsigned int cmd,

unsigned long arg)

{

struct inode *inode = filp->f_path.dentry->d_inode;

int __user *p = (int __user *)arg;

switch (cmd) {

case FIBMAP:

return ioctl_fibmap(filp, p);

case FIONREAD:

return put_user(i_size_read(inode) - filp->f_pos, p);

case FS_IOC_RESVSP:

case FS_IOC_RESVSP64:

return ioctl_preallocate(filp, p);

}

return vfs_ioctl(filp, cmd, arg);

}

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

spin_lock(&filp->f_lock);

if (on)

filp->f_flags |= flag;

else

filp->f_flags &= ~flag;

spin_unlock(&filp->f_lock);

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) {

if (filp->f_op && filp->f_op->fasync)

/* fasync() adjusts filp->f_flags */

error = filp->f_op->fasync(fd, filp, on);

else

error = -ENOTTY;

}

return error < 0 ? error : 0;

}

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);

}

/*

* When you add any new common ioctls to the switches above and below

* please update compat_sys_ioctl() too.

*

* do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.

* It's just a simple helper for sys_ioctl and compat_sys_ioctl.

*/

int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,

unsigned long arg)

{

int error = 0;

int __user *argp = (int __user *)arg;

switch (cmd) {

case FIOCLEX:

set_close_on_exec(fd, 1);

break;

case FIONCLEX:

set_close_on_exec(fd, 0);

break;

case FIONBIO:

error = ioctl_fionbio(filp, argp);

break;

case FIOASYNC:

error = ioctl_fioasync(fd, filp, argp);

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;

case FIFREEZE:

error = ioctl_fsfreeze(filp);

break;

case FITHAW:

error = ioctl_fsthaw(filp);

break;

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);

}

default:

if (S_ISREG(filp->f_path.dentry->d_inode->i_mode))

error = file_ioctl(filp, cmd, arg);

else

error = vfs_ioctl(filp, cmd, arg);

break;

}

return error;

}

SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)

{

struct file *filp;

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;

error = do_vfs_ioctl(filp, fd, cmd, arg);

out_fput:

fput_light(filp, fput_needed);

out:

return error;

}