/*
   *  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)

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

  		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:

  		/* BKL needed to avoid races tweaking f_flags */
  		lock_kernel();

  		error = ioctl_fionbio(filp, argp);

  		unlock_kernel();

  		break;
  
  	case FIOASYNC:

  		/* BKL needed to avoid races tweaking f_flags */
  		lock_kernel();

  		error = ioctl_fioasync(fd, filp, argp);

  		unlock_kernel();

  		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;
  }