/*
   *  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

   * 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 || !filp->f_op->unlocked_ioctl)

  		goto out;

  	error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
  	if (error == -ENOIOCTLCMD)
  		error = -EINVAL;

   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;
  	}

  	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;

  	/* Freeze */

  	return freeze_super(sb);

  }
  
  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;

  	/* Thaw */

  	return thaw_super(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;
  }