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DEFINITIONS
This source file includes following definitions.
- vfs_ioctl
- ioctl_fibmap
- fiemap_fill_next_extent
- fiemap_check_flags
- fiemap_check_ranges
- ioctl_fiemap
- generic_block_fiemap
- file_ioctl
- ioctl_fionbio
- ioctl_fioasync
- do_vfs_ioctl
- sys_ioctl
/*
* 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 <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;
lock_kernel();
res = mapping->a_ops->bmap(mapping, block);
unlock_kernel();
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)
{
*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;
}
#ifdef CONFIG_BLOCK
#define blk_to_logical(inode, blk) (blk << (inode)->i_blkbits)
#define logical_to_blk(inode, offset) (offset >> (inode)->i_blkbits);
/*
* @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
* beyond i_size
*/
int generic_block_fiemap(struct inode *inode,
struct fiemap_extent_info *fieinfo, u64 start,
u64 len, get_block_t *get_block)
{
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;
int ret = 0;
if ((ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC)))
return ret;
start_blk = logical_to_blk(inode, start);
/* guard against change */
mutex_lock(&inode->i_mutex);
length = (long long)min_t(u64, len, i_size_read(inode));
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)) {
/*
* first hole after going past the EOF, this is our
* last extent
*/
if (length <= 0) {
flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST;
ret = fiemap_fill_next_extent(fieinfo, logical,
phys, size,
flags);
break;
}
length -= blk_to_logical(inode, 1);
/* if we have holes up to/past EOF then we're done */
if (length <= 0)
break;
start_blk++;
} else {
if (length <= 0 && 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, tmp.b_blocknr);
size = tmp.b_size;
flags = FIEMAP_EXTENT_MERGED;
length -= tmp.b_size;
start_blk += logical_to_blk(inode, size);
/*
* if we are past the EOF we need to loop again to see
* if there is a hole so we can mark this extent as the
* last one, and if not keep mapping things until we
* find a hole, or we run out of slots in the extent
* array
*/
if (length <= 0)
continue;
ret = fiemap_fill_next_extent(fieinfo, logical, phys,
size, flags);
if (ret)
break;
}
cond_resched();
} while (1);
mutex_unlock(&inode->i_mutex);
/* 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);
#endif /* CONFIG_BLOCK */
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 FS_IOC_FIEMAP:
return ioctl_fiemap(filp, arg);
case FIGETBSZ:
return put_user(inode->i_sb->s_blocksize, p);
case FIONREAD:
return put_user(i_size_read(inode) - filp->f_pos, 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
if (on)
filp->f_flags |= flag;
else
filp->f_flags &= ~flag;
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) {
lock_kernel();
error = filp->f_op->fasync(fd, filp, on);
unlock_kernel();
} else
error = -ENOTTY;
}
if (error)
return error;
if (on)
filp->f_flags |= FASYNC;
else
filp->f_flags &= ~FASYNC;
return error;
}
/*
* 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;
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;
}
asmlinkage long sys_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;
}