/*
   * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.

   * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.

   *
   * This copyrighted material is made available to anyone wishing to use,
   * modify, copy, or redistribute it subject to the terms and conditions

   * of the GNU General Public License version 2.

   */
  
  #include <linux/sched.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>
  #include <linux/completion.h>
  #include <linux/buffer_head.h>
  #include <linux/posix_acl.h>
  #include <linux/posix_acl_xattr.h>

  #include <linux/gfs2_ondisk.h>

  
  #include "gfs2.h"

  #include "incore.h"

  #include "acl.h"

  #include "xattr.h"

  #include "glock.h"
  #include "inode.h"
  #include "meta_io.h"
  #include "trans.h"

  #include "util.h"

  
  #define ACL_ACCESS 1
  #define ACL_DEFAULT 0
  
  int gfs2_acl_validate_set(struct gfs2_inode *ip, int access,

  			  struct gfs2_ea_request *er, int *remove, mode_t *mode)

  {
  	struct posix_acl *acl;
  	int error;
  
  	error = gfs2_acl_validate_remove(ip, access);
  	if (error)
  		return error;
  
  	if (!er->er_data)
  		return -EINVAL;
  
  	acl = posix_acl_from_xattr(er->er_data, er->er_data_len);
  	if (IS_ERR(acl))
  		return PTR_ERR(acl);
  	if (!acl) {
  		*remove = 1;
  		return 0;
  	}
  
  	error = posix_acl_valid(acl);
  	if (error)
  		goto out;
  
  	if (access) {
  		error = posix_acl_equiv_mode(acl, mode);
  		if (!error)
  			*remove = 1;
  		else if (error > 0)
  			error = 0;
  	}

  out:

  	posix_acl_release(acl);

  	return error;
  }
  
  int gfs2_acl_validate_remove(struct gfs2_inode *ip, int access)
  {

  	if (!GFS2_SB(&ip->i_inode)->sd_args.ar_posix_acl)

  		return -EOPNOTSUPP;

  	if (!is_owner_or_cap(&ip->i_inode))

  		return -EPERM;

  	if (S_ISLNK(ip->i_inode.i_mode))

  		return -EOPNOTSUPP;

  	if (!access && !S_ISDIR(ip->i_inode.i_mode))

  		return -EACCES;
  
  	return 0;
  }

  static int acl_get(struct gfs2_inode *ip, const char *name,
  		   struct posix_acl **acl, struct gfs2_ea_location *el,
  		   char **datap, unsigned int *lenp)

  {

  	char *data;
  	unsigned int len;

  	int error;

  	el->el_bh = NULL;

  	if (!ip->i_eattr)

  		return 0;

  	error = gfs2_ea_find(ip, GFS2_EATYPE_SYS, name, el);

  	if (error)
  		return error;
  	if (!el->el_ea)
  		return 0;
  	if (!GFS2_EA_DATA_LEN(el->el_ea))
  		goto out;

  	len = GFS2_EA_DATA_LEN(el->el_ea);
  	data = kmalloc(len, GFP_NOFS);

  	error = -ENOMEM;

  	if (!data)

  		goto out;

  	error = gfs2_ea_get_copy(ip, el, data, len);
  	if (error < 0)

  		goto out_kfree;

  	error = 0;

  
  	if (acl) {

  		*acl = posix_acl_from_xattr(data, len);

  		if (IS_ERR(*acl))
  			error = PTR_ERR(*acl);
  	}

  out_kfree:

  	if (error || !datap) {
  		kfree(data);
  	} else {
  		*datap = data;
  		*lenp = len;

  	}

  out:

  	return error;
  }
  
  /**

   * gfs2_check_acl - Check an ACL to see if we're allowed to do something

   * @inode: the file we want to do something to
   * @mask: what we want to do
   *
   * Returns: errno
   */

  int gfs2_check_acl(struct inode *inode, int mask)

  {

  	struct gfs2_ea_location el;

  	struct posix_acl *acl = NULL;
  	int error;

  	error = acl_get(GFS2_I(inode), GFS2_POSIX_ACL_ACCESS, &acl, &el, NULL, NULL);
  	brelse(el.el_bh);

  	if (error)
  		return error;
  
  	if (acl) {
  		error = posix_acl_permission(inode, acl, mask);
  		posix_acl_release(acl);
  		return error;
  	}
  
  	return -EAGAIN;
  }

  static int munge_mode(struct gfs2_inode *ip, mode_t mode)
  {

  	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);

  	struct buffer_head *dibh;
  	int error;
  
  	error = gfs2_trans_begin(sdp, RES_DINODE, 0);
  	if (error)
  		return error;
  
  	error = gfs2_meta_inode_buffer(ip, &dibh);
  	if (!error) {
  		gfs2_assert_withdraw(sdp,

  				(ip->i_inode.i_mode & S_IFMT) == (mode & S_IFMT));
  		ip->i_inode.i_mode = mode;

  		gfs2_trans_add_bh(ip->i_gl, dibh, 1);

  		gfs2_dinode_out(ip, dibh->b_data);

  		brelse(dibh);
  	}
  
  	gfs2_trans_end(sdp);
  
  	return 0;
  }
  
  int gfs2_acl_create(struct gfs2_inode *dip, struct gfs2_inode *ip)
  {

  	struct gfs2_ea_location el;

  	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);

  	struct posix_acl *acl = NULL, *clone;

  	mode_t mode = ip->i_inode.i_mode;

  	char *data = NULL;
  	unsigned int len;

  	int error;
  
  	if (!sdp->sd_args.ar_posix_acl)
  		return 0;

  	if (S_ISLNK(ip->i_inode.i_mode))

  		return 0;

  	error = acl_get(dip, GFS2_POSIX_ACL_DEFAULT, &acl, &el, &data, &len);
  	brelse(el.el_bh);

  	if (error)
  		return error;
  	if (!acl) {

  		mode &= ~current_umask();

  		if (mode != ip->i_inode.i_mode)

  			error = munge_mode(ip, mode);
  		return error;
  	}

  	clone = posix_acl_clone(acl, GFP_NOFS);

  	error = -ENOMEM;
  	if (!clone)
  		goto out;
  	posix_acl_release(acl);
  	acl = clone;

  	if (S_ISDIR(ip->i_inode.i_mode)) {

  		error = gfs2_xattr_set(&ip->i_inode, GFS2_EATYPE_SYS,
  				       GFS2_POSIX_ACL_DEFAULT, data, len, 0);

  		if (error)
  			goto out;
  	}
  
  	error = posix_acl_create_masq(acl, &mode);
  	if (error < 0)
  		goto out;

  	if (error == 0)
  		goto munge;

  	posix_acl_to_xattr(acl, data, len);
  	error = gfs2_xattr_set(&ip->i_inode, GFS2_EATYPE_SYS,
  			       GFS2_POSIX_ACL_ACCESS, data, len, 0);
  	if (error)
  		goto out;
  munge:
  	error = munge_mode(ip, mode);

  out:

  	posix_acl_release(acl);

  	kfree(data);

  	return error;
  }
  
  int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr)
  {
  	struct posix_acl *acl = NULL, *clone;
  	struct gfs2_ea_location el;
  	char *data;
  	unsigned int len;
  	int error;

  	error = acl_get(ip, GFS2_POSIX_ACL_ACCESS, &acl, &el, &data, &len);

  	if (error)

  		goto out_brelse;

  	if (!acl)
  		return gfs2_setattr_simple(ip, attr);

  	clone = posix_acl_clone(acl, GFP_NOFS);

  	error = -ENOMEM;
  	if (!clone)
  		goto out;
  	posix_acl_release(acl);
  	acl = clone;
  
  	error = posix_acl_chmod_masq(acl, attr->ia_mode);
  	if (!error) {
  		posix_acl_to_xattr(acl, data, len);
  		error = gfs2_ea_acl_chmod(ip, &el, attr, data);
  	}

  out:

  	posix_acl_release(acl);

  	kfree(data);

  out_brelse:
  	brelse(el.el_bh);

  	return error;
  }