path: root/fs/xfs/linux-2.6/xfs_ioctl.c

/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_alloc.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_attr_sf.h"
#include "xfs_dir2_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_rtalloc.h"
#include "xfs_itable.h"
#include "xfs_error.h"
#include "xfs_rw.h"
#include "xfs_acl.h"
#include "xfs_attr.h"
#include "xfs_bmap.h"
#include "xfs_buf_item.h"
#include "xfs_utils.h"
#include "xfs_dfrag.h"
#include "xfs_fsops.h"
#include "xfs_vnodeops.h"
#include "xfs_quota.h"
#include "xfs_inode_item.h"

#include <linux/capability.h>
#include <linux/dcache.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/pagemap.h>

/*
 * xfs_find_handle maps from userspace xfs_fsop_handlereq structure to
 * a file or fs handle.
 *
 * XFS_IOC_PATH_TO_FSHANDLE
 *    returns fs handle for a mount point or path within that mount point
 * XFS_IOC_FD_TO_HANDLE
 *    returns full handle for a FD opened in user space
 * XFS_IOC_PATH_TO_HANDLE
 *    returns full handle for a path
 */
STATIC int
xfs_find_handle(
	unsigned int		cmd,
	void			__user *arg)
{
	int			hsize;
	xfs_handle_t		handle;
	xfs_fsop_handlereq_t	hreq;
	struct inode		*inode;

	if (copy_from_user(&hreq, arg, sizeof(hreq)))
		return -XFS_ERROR(EFAULT);

	memset((char *)&handle, 0, sizeof(handle));

	switch (cmd) {
	case XFS_IOC_PATH_TO_FSHANDLE:
	case XFS_IOC_PATH_TO_HANDLE: {
		struct path path;
		int error = user_lpath((const char __user *)hreq.path, &path);
		if (error)
			return error;

		ASSERT(path.dentry);
		ASSERT(path.dentry->d_inode);
		inode = igrab(path.dentry->d_inode);
		path_put(&path);
		break;
	}

	case XFS_IOC_FD_TO_HANDLE: {
		struct file	*file;

		file = fget(hreq.fd);
		if (!file)
		    return -EBADF;

		ASSERT(file->f_path.dentry);
		ASSERT(file->f_path.dentry->d_inode);
		inode = igrab(file->f_path.dentry->d_inode);
		fput(file);
		break;
	}

	default:
		ASSERT(0);
		return -XFS_ERROR(EINVAL);
	}

	if (inode->i_sb->s_magic != XFS_SB_MAGIC) {
		/* we're not in XFS anymore, Toto */
		iput(inode);
		return -XFS_ERROR(EINVAL);
	}

	switch (inode->i_mode & S_IFMT) {
	case S_IFREG:
	case S_IFDIR:
	case S_IFLNK:
		break;
	default:
		iput(inode);
		return -XFS_ERROR(EBADF);
	}

	/* now we can grab the fsid */
	memcpy(&handle.ha_fsid, XFS_I(inode)->i_mount->m_fixedfsid,
			sizeof(xfs_fsid_t));
	hsize = sizeof(xfs_fsid_t);

	if (cmd != XFS_IOC_PATH_TO_FSHANDLE) {
		xfs_inode_t	*ip = XFS_I(inode);
		int		lock_mode;

		/* need to get access to the xfs_inode to read the generation */
		lock_mode = xfs_ilock_map_shared(ip);

		/* fill in fid section of handle from inode */
		handle.ha_fid.fid_len = sizeof(xfs_fid_t) -
					sizeof(handle.ha_fid.fid_len);
		handle.ha_fid.fid_pad = 0;
		handle.ha_fid.fid_gen = ip->i_d.di_gen;
		handle.ha_fid.fid_ino = ip->i_ino;

		xfs_iunlock_map_shared(ip, lock_mode);

		hsize = XFS_HSIZE(handle);
	}

	/* now copy our handle into the user buffer & write out the size */
	if (copy_to_user(hreq.ohandle, &handle, hsize) ||
	    copy_to_user(hreq.ohandlen, &hsize, sizeof(__s32))) {
		iput(inode);
		return -XFS_ERROR(EFAULT);
	}

	iput(inode);
	return 0;
}


/*
 * Convert userspace handle data into inode.
 *
 * We use the fact that all the fsop_handlereq ioctl calls have a data
 * structure argument whose first component is always a xfs_fsop_handlereq_t,
 * so we can pass that sub structure into this handy, shared routine.
 *
 * If no error, caller must always iput the returned inode.
 */
STATIC int
xfs_vget_fsop_handlereq(
	xfs_mount_t		*mp,
	struct inode		*parinode,	/* parent inode pointer    */
	xfs_fsop_handlereq_t	*hreq,
	struct inode		**inode)
{
	void			__user *hanp;
	size_t			hlen;
	xfs_fid_t		*xfid;
	xfs_handle_t		*handlep;
	xfs_handle_t		handle;
	xfs_inode_t		*ip;
	xfs_ino_t		ino;
	__u32			igen;
	int			error;

	/*
	 * Only allow handle opens under a directory.
	 */
	if (!S_ISDIR(parinode->i_mode))
		return XFS_ERROR(ENOTDIR);

	hanp = hreq->ihandle;
	hlen = hreq->ihandlen;
	handlep = &handle;

	if (hlen < sizeof(handlep->ha_fsid) || hlen > sizeof(*handlep))
		return XFS_ERROR(EINVAL);
	if (copy_from_user(handlep, hanp, hlen))
		return XFS_ERROR(EFAULT);
	if (hlen < sizeof(*handlep))
		memset(((char *)handlep) + hlen, 0, sizeof(*handlep) - hlen);
	if (hlen > sizeof(handlep->ha_fsid)) {
		if (handlep->ha_fid.fid_len !=
		    (hlen - sizeof(handlep->ha_fsid) -
		            sizeof(handlep->ha_fid.fid_len)) ||