/*
   * 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/xattr.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"

  static const char *gfs2_acl_name(int type)

  {

  	switch (type) {
  	case ACL_TYPE_ACCESS:
  		return GFS2_POSIX_ACL_ACCESS;
  	case ACL_TYPE_DEFAULT:
  		return GFS2_POSIX_ACL_DEFAULT;
  	}
  	return NULL;
  }

  static struct posix_acl *gfs2_acl_get(struct gfs2_inode *ip, int type)
  {
  	struct posix_acl *acl;
  	const char *name;
  	char *data;
  	int len;

  	if (!ip->i_eattr)

  		return NULL;

  	acl = get_cached_acl(&ip->i_inode, type);
  	if (acl != ACL_NOT_CACHED)
  		return acl;

  	name = gfs2_acl_name(type);
  	if (name == NULL)
  		return ERR_PTR(-EINVAL);

  	len = gfs2_xattr_acl_get(ip, name, &data);
  	if (len < 0)
  		return ERR_PTR(len);
  	if (len == 0)
  		return NULL;

  	acl = posix_acl_from_xattr(data, len);
  	kfree(data);
  	return acl;

  }

  struct posix_acl *gfs2_get_acl(struct inode *inode, int type)

  {

  	return gfs2_acl_get(GFS2_I(inode), type);

  }

  static int gfs2_set_mode(struct inode *inode, umode_t mode)

  {

  	int error = 0;

  	if (mode != inode->i_mode) {
  		struct iattr iattr;

  		iattr.ia_valid = ATTR_MODE;
  		iattr.ia_mode = mode;

  		error = gfs2_setattr_simple(GFS2_I(inode), &iattr);
  	}

  	return error;

  }

  static int gfs2_acl_set(struct inode *inode, int type, struct posix_acl *acl)

  {

  	int error;

  	int len;
  	char *data;
  	const char *name = gfs2_acl_name(type);
  
  	BUG_ON(name == NULL);
  	len = posix_acl_to_xattr(acl, NULL, 0);
  	if (len == 0)
  		return 0;
  	data = kmalloc(len, GFP_NOFS);
  	if (data == NULL)
  		return -ENOMEM;
  	error = posix_acl_to_xattr(acl, data, len);
  	if (error < 0)
  		goto out;

  	error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);

  	if (!error)
  		set_cached_acl(inode, type, acl);

  out:
  	kfree(data);
  	return error;
  }
  
  int gfs2_acl_create(struct gfs2_inode *dip, struct inode *inode)
  {
  	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);

  	struct posix_acl *acl;

  	umode_t mode = inode->i_mode;

  	int error = 0;

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

  	if (S_ISLNK(inode->i_mode))

  		return 0;

  	acl = gfs2_acl_get(dip, ACL_TYPE_DEFAULT);
  	if (IS_ERR(acl))
  		return PTR_ERR(acl);

  	if (!acl) {

  		mode &= ~current_umask();

  		if (mode != inode->i_mode)
  			error = gfs2_set_mode(inode, mode);

  		return error;
  	}

  	if (S_ISDIR(inode->i_mode)) {
  		error = gfs2_acl_set(inode, ACL_TYPE_DEFAULT, acl);
  		if (error)
  			goto out;
  	}

  	error = posix_acl_create(&acl, GFP_NOFS, &mode);

  	if (error < 0)

  		return error;

  	if (error == 0)
  		goto munge;

  	error = gfs2_acl_set(inode, ACL_TYPE_ACCESS, acl);

  	if (error)
  		goto out;
  munge:

  	error = gfs2_set_mode(inode, mode);

  out:

  	posix_acl_release(acl);

  	return error;
  }
  
  int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr)
  {

  	struct posix_acl *acl;

  	char *data;
  	unsigned int len;
  	int error;

  	acl = gfs2_acl_get(ip, ACL_TYPE_ACCESS);
  	if (IS_ERR(acl))
  		return PTR_ERR(acl);

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

  	error = posix_acl_chmod(&acl, GFP_NOFS, attr->ia_mode);
  	if (error)
  		return error;
  
  	len = posix_acl_to_xattr(acl, NULL, 0);
  	data = kmalloc(len, GFP_NOFS);

  	error = -ENOMEM;

  	if (data == NULL)

  		goto out;

  	posix_acl_to_xattr(acl, data, len);
  	error = gfs2_xattr_acl_chmod(ip, attr, data);
  	kfree(data);
  	set_cached_acl(&ip->i_inode, ACL_TYPE_ACCESS, acl);

  out:

  	posix_acl_release(acl);

  	return error;
  }

  static int gfs2_acl_type(const char *name)
  {
  	if (strcmp(name, GFS2_POSIX_ACL_ACCESS) == 0)
  		return ACL_TYPE_ACCESS;
  	if (strcmp(name, GFS2_POSIX_ACL_DEFAULT) == 0)
  		return ACL_TYPE_DEFAULT;
  	return -EINVAL;
  }

  static int gfs2_xattr_system_get(struct dentry *dentry, const char *name,
  				 void *buffer, size_t size, int xtype)

  {

  	struct inode *inode = dentry->d_inode;

  	struct gfs2_sbd *sdp = GFS2_SB(inode);

  	struct posix_acl *acl;

  	int type;

  	int error;

  	if (!sdp->sd_args.ar_posix_acl)
  		return -EOPNOTSUPP;

  	type = gfs2_acl_type(name);
  	if (type < 0)
  		return type;

  	acl = gfs2_acl_get(GFS2_I(inode), type);
  	if (IS_ERR(acl))
  		return PTR_ERR(acl);
  	if (acl == NULL)
  		return -ENODATA;

  	error = posix_acl_to_xattr(acl, buffer, size);
  	posix_acl_release(acl);
  
  	return error;
  }

  static int gfs2_xattr_system_set(struct dentry *dentry, const char *name,
  				 const void *value, size_t size, int flags,
  				 int xtype)

  {

  	struct inode *inode = dentry->d_inode;

  	struct gfs2_sbd *sdp = GFS2_SB(inode);
  	struct posix_acl *acl = NULL;
  	int error = 0, type;
  
  	if (!sdp->sd_args.ar_posix_acl)
  		return -EOPNOTSUPP;
  
  	type = gfs2_acl_type(name);
  	if (type < 0)
  		return type;
  	if (flags & XATTR_CREATE)
  		return -EINVAL;
  	if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
  		return value ? -EACCES : 0;
  	if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
  		return -EPERM;
  	if (S_ISLNK(inode->i_mode))
  		return -EOPNOTSUPP;
  
  	if (!value)
  		goto set_acl;
  
  	acl = posix_acl_from_xattr(value, size);
  	if (!acl) {
  		/*
  		 * acl_set_file(3) may request that we set default ACLs with
  		 * zero length -- defend (gracefully) against that here.
  		 */
  		goto out;
  	}
  	if (IS_ERR(acl)) {
  		error = PTR_ERR(acl);
  		goto out;
  	}
  
  	error = posix_acl_valid(acl);
  	if (error)
  		goto out_release;
  
  	error = -EINVAL;
  	if (acl->a_count > GFS2_ACL_MAX_ENTRIES)
  		goto out_release;
  
  	if (type == ACL_TYPE_ACCESS) {

  		umode_t mode = inode->i_mode;

  		error = posix_acl_equiv_mode(acl, &mode);
  
  		if (error <= 0) {
  			posix_acl_release(acl);
  			acl = NULL;
  
  			if (error < 0)
  				return error;
  		}
  
  		error = gfs2_set_mode(inode, mode);
  		if (error)
  			goto out_release;
  	}
  
  set_acl:

  	error = __gfs2_xattr_set(inode, name, value, size, 0, GFS2_EATYPE_SYS);

  	if (!error) {
  		if (acl)
  			set_cached_acl(inode, type, acl);
  		else
  			forget_cached_acl(inode, type);
  	}

  out_release:
  	posix_acl_release(acl);
  out:
  	return error;
  }

  const struct xattr_handler gfs2_xattr_system_handler = {

  	.prefix = XATTR_SYSTEM_PREFIX,

  	.flags  = GFS2_EATYPE_SYS,

  	.get    = gfs2_xattr_system_get,
  	.set    = gfs2_xattr_system_set,
  };