/* -*- mode: c; c-basic-offset: 8; -*-
   * vim: noexpandtab sw=8 ts=8 sts=0:
   *
   * acl.c
   *
   * Copyright (C) 2004, 2008 Oracle.  All rights reserved.
   *
   * CREDITS:
   * Lots of code in this file is copy from linux/fs/ext3/acl.c.
   * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public
   * License version 2 as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will 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.
   */
  
  #include <linux/init.h>
  #include <linux/module.h>

  #include <linux/slab.h>

  #include <linux/string.h>

  #include <cluster/masklog.h>
  
  #include "ocfs2.h"
  #include "alloc.h"
  #include "dlmglue.h"
  #include "file.h"

  #include "inode.h"
  #include "journal.h"

  #include "ocfs2_fs.h"
  
  #include "xattr.h"
  #include "acl.h"
  
  /*
   * Convert from xattr value to acl struct.
   */
  static struct posix_acl *ocfs2_acl_from_xattr(const void *value, size_t size)
  {
  	int n, count;
  	struct posix_acl *acl;
  
  	if (!value)
  		return NULL;
  	if (size < sizeof(struct posix_acl_entry))
  		return ERR_PTR(-EINVAL);
  
  	count = size / sizeof(struct posix_acl_entry);
  	if (count < 0)
  		return ERR_PTR(-EINVAL);
  	if (count == 0)
  		return NULL;
  
  	acl = posix_acl_alloc(count, GFP_NOFS);
  	if (!acl)
  		return ERR_PTR(-ENOMEM);
  	for (n = 0; n < count; n++) {
  		struct ocfs2_acl_entry *entry =
  			(struct ocfs2_acl_entry *)value;
  
  		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
  		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
  		acl->a_entries[n].e_id   = le32_to_cpu(entry->e_id);
  		value += sizeof(struct posix_acl_entry);
  
  	}
  	return acl;
  }
  
  /*
   * Convert acl struct to xattr value.
   */
  static void *ocfs2_acl_to_xattr(const struct posix_acl *acl, size_t *size)
  {
  	struct ocfs2_acl_entry *entry = NULL;
  	char *ocfs2_acl;
  	size_t n;
  
  	*size = acl->a_count * sizeof(struct posix_acl_entry);
  
  	ocfs2_acl = kmalloc(*size, GFP_NOFS);
  	if (!ocfs2_acl)
  		return ERR_PTR(-ENOMEM);
  
  	entry = (struct ocfs2_acl_entry *)ocfs2_acl;
  	for (n = 0; n < acl->a_count; n++, entry++) {
  		entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
  		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
  		entry->e_id   = cpu_to_le32(acl->a_entries[n].e_id);
  	}
  	return ocfs2_acl;
  }
  
  static struct posix_acl *ocfs2_get_acl_nolock(struct inode *inode,
  					      int type,
  					      struct buffer_head *di_bh)
  {

  	int name_index;
  	char *value = NULL;
  	struct posix_acl *acl;
  	int retval;

  	switch (type) {
  	case ACL_TYPE_ACCESS:
  		name_index = OCFS2_XATTR_INDEX_POSIX_ACL_ACCESS;
  		break;
  	case ACL_TYPE_DEFAULT:
  		name_index = OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT;
  		break;
  	default:
  		return ERR_PTR(-EINVAL);
  	}
  
  	retval = ocfs2_xattr_get_nolock(inode, di_bh, name_index, "", NULL, 0);
  	if (retval > 0) {
  		value = kmalloc(retval, GFP_NOFS);
  		if (!value)
  			return ERR_PTR(-ENOMEM);
  		retval = ocfs2_xattr_get_nolock(inode, di_bh, name_index,
  						"", value, retval);
  	}
  
  	if (retval > 0)
  		acl = ocfs2_acl_from_xattr(value, retval);
  	else if (retval == -ENODATA || retval == 0)
  		acl = NULL;
  	else
  		acl = ERR_PTR(retval);
  
  	kfree(value);
  
  	return acl;
  }
  
  
  /*
   * Get posix acl.
   */
  static struct posix_acl *ocfs2_get_acl(struct inode *inode, int type)
  {
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	struct buffer_head *di_bh = NULL;
  	struct posix_acl *acl;
  	int ret;
  
  	if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
  		return NULL;
  
  	ret = ocfs2_inode_lock(inode, &di_bh, 0);
  	if (ret < 0) {
  		mlog_errno(ret);
  		acl = ERR_PTR(ret);
  		return acl;
  	}
  
  	acl = ocfs2_get_acl_nolock(inode, type, di_bh);
  
  	ocfs2_inode_unlock(inode, 0);
  
  	brelse(di_bh);
  
  	return acl;
  }
  
  /*

   * Helper function to set i_mode in memory and disk. Some call paths
   * will not have di_bh or a journal handle to pass, in which case it
   * will create it's own.
   */
  static int ocfs2_acl_set_mode(struct inode *inode, struct buffer_head *di_bh,
  			      handle_t *handle, umode_t new_mode)
  {
  	int ret, commit_handle = 0;
  	struct ocfs2_dinode *di;
  
  	if (di_bh == NULL) {
  		ret = ocfs2_read_inode_block(inode, &di_bh);
  		if (ret) {
  			mlog_errno(ret);
  			goto out;
  		}
  	} else
  		get_bh(di_bh);
  
  	if (handle == NULL) {
  		handle = ocfs2_start_trans(OCFS2_SB(inode->i_sb),
  					   OCFS2_INODE_UPDATE_CREDITS);
  		if (IS_ERR(handle)) {
  			ret = PTR_ERR(handle);
  			mlog_errno(ret);
  			goto out_brelse;
  		}
  
  		commit_handle = 1;
  	}
  
  	di = (struct ocfs2_dinode *)di_bh->b_data;
  	ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
  				      OCFS2_JOURNAL_ACCESS_WRITE);
  	if (ret) {
  		mlog_errno(ret);
  		goto out_commit;
  	}
  
  	inode->i_mode = new_mode;

  	inode->i_ctime = CURRENT_TIME;

  	di->i_mode = cpu_to_le16(inode->i_mode);

  	di->i_ctime = cpu_to_le64(inode->i_ctime.tv_sec);
  	di->i_ctime_nsec = cpu_to_le32(inode->i_ctime.tv_nsec);

  
  	ocfs2_journal_dirty(handle, di_bh);
  
  out_commit:
  	if (commit_handle)
  		ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle);
  out_brelse:
  	brelse(di_bh);
  out:
  	return ret;
  }
  
  /*

   * Set the access or default ACL of an inode.
   */
  static int ocfs2_set_acl(handle_t *handle,
  			 struct inode *inode,
  			 struct buffer_head *di_bh,
  			 int type,
  			 struct posix_acl *acl,
  			 struct ocfs2_alloc_context *meta_ac,
  			 struct ocfs2_alloc_context *data_ac)
  {
  	int name_index;
  	void *value = NULL;
  	size_t size = 0;
  	int ret;
  
  	if (S_ISLNK(inode->i_mode))
  		return -EOPNOTSUPP;
  
  	switch (type) {
  	case ACL_TYPE_ACCESS:
  		name_index = OCFS2_XATTR_INDEX_POSIX_ACL_ACCESS;
  		if (acl) {

  			umode_t mode = inode->i_mode;

  			ret = posix_acl_equiv_mode(acl, &mode);
  			if (ret < 0)
  				return ret;
  			else {

  				if (ret == 0)
  					acl = NULL;

  
  				ret = ocfs2_acl_set_mode(inode, di_bh,
  							 handle, mode);
  				if (ret)
  					return ret;

  			}
  		}
  		break;
  	case ACL_TYPE_DEFAULT:
  		name_index = OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT;
  		if (!S_ISDIR(inode->i_mode))
  			return acl ? -EACCES : 0;
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	if (acl) {
  		value = ocfs2_acl_to_xattr(acl, &size);
  		if (IS_ERR(value))
  			return (int)PTR_ERR(value);
  	}
  
  	if (handle)
  		ret = ocfs2_xattr_set_handle(handle, inode, di_bh, name_index,
  					     "", value, size, 0,
  					     meta_ac, data_ac);
  	else
  		ret = ocfs2_xattr_set(inode, name_index, "", value, size, 0);
  
  	kfree(value);
  
  	return ret;
  }

  struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type)

  {

  	struct ocfs2_super *osb;

  	struct buffer_head *di_bh = NULL;
  	struct posix_acl *acl;
  	int ret = -EAGAIN;

  	osb = OCFS2_SB(inode->i_sb);

  	if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))

  		return NULL;

  	ret = ocfs2_read_inode_block(inode, &di_bh);

  	if (ret < 0)
  		return ERR_PTR(ret);

  	acl = ocfs2_get_acl_nolock(inode, type, di_bh);

  
  	brelse(di_bh);

  	return acl;

  }

  int ocfs2_acl_chmod(struct inode *inode)
  {
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

  	struct posix_acl *acl;

  	int ret;
  
  	if (S_ISLNK(inode->i_mode))
  		return -EOPNOTSUPP;
  
  	if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
  		return 0;
  
  	acl = ocfs2_get_acl(inode, ACL_TYPE_ACCESS);
  	if (IS_ERR(acl) || !acl)
  		return PTR_ERR(acl);

  	ret = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
  	if (ret)
  		return ret;
  	ret = ocfs2_set_acl(NULL, inode, NULL, ACL_TYPE_ACCESS,
  			    acl, NULL, NULL);

  	posix_acl_release(acl);

  	return ret;
  }

  /*
   * Initialize the ACLs of a new inode. If parent directory has default ACL,
   * then clone to new inode. Called from ocfs2_mknod.
   */
  int ocfs2_init_acl(handle_t *handle,
  		   struct inode *inode,
  		   struct inode *dir,
  		   struct buffer_head *di_bh,
  		   struct buffer_head *dir_bh,
  		   struct ocfs2_alloc_context *meta_ac,
  		   struct ocfs2_alloc_context *data_ac)
  {
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	struct posix_acl *acl = NULL;

  	int ret = 0, ret2;

  	umode_t mode;

  
  	if (!S_ISLNK(inode->i_mode)) {
  		if (osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL) {
  			acl = ocfs2_get_acl_nolock(dir, ACL_TYPE_DEFAULT,
  						   dir_bh);
  			if (IS_ERR(acl))
  				return PTR_ERR(acl);
  		}

  		if (!acl) {
  			mode = inode->i_mode & ~current_umask();
  			ret = ocfs2_acl_set_mode(inode, di_bh, handle, mode);
  			if (ret) {
  				mlog_errno(ret);
  				goto cleanup;
  			}
  		}

  	}
  	if ((osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL) && acl) {

  		if (S_ISDIR(inode->i_mode)) {
  			ret = ocfs2_set_acl(handle, inode, di_bh,
  					    ACL_TYPE_DEFAULT, acl,
  					    meta_ac, data_ac);
  			if (ret)
  				goto cleanup;
  		}

  		mode = inode->i_mode;

  		ret = posix_acl_create(&acl, GFP_NOFS, &mode);
  		if (ret < 0)
  			return ret;
  
  		ret2 = ocfs2_acl_set_mode(inode, di_bh, handle, mode);
  		if (ret2) {
  			mlog_errno(ret2);
  			ret = ret2;
  			goto cleanup;
  		}
  		if (ret > 0) {
  			ret = ocfs2_set_acl(handle, inode,
  					    di_bh, ACL_TYPE_ACCESS,
  					    acl, meta_ac, data_ac);

  		}

  	}
  cleanup:
  	posix_acl_release(acl);
  	return ret;
  }

  static size_t ocfs2_xattr_list_acl_access(struct dentry *dentry,

  					  char *list,
  					  size_t list_len,
  					  const char *name,

  					  size_t name_len,
  					  int type)

  {

  	struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);

  	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
  
  	if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
  		return 0;
  
  	if (list && size <= list_len)
  		memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
  	return size;
  }

  static size_t ocfs2_xattr_list_acl_default(struct dentry *dentry,

  					   char *list,
  					   size_t list_len,
  					   const char *name,

  					   size_t name_len,
  					   int type)

  {

  	struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);

  	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
  
  	if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
  		return 0;
  
  	if (list && size <= list_len)
  		memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
  	return size;
  }

  static int ocfs2_xattr_get_acl(struct dentry *dentry, const char *name,
  		void *buffer, size_t size, int type)

  {

  	struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);

  	struct posix_acl *acl;
  	int ret;

  	if (strcmp(name, "") != 0)
  		return -EINVAL;

  	if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
  		return -EOPNOTSUPP;

  	acl = ocfs2_get_acl(dentry->d_inode, type);

  	if (IS_ERR(acl))
  		return PTR_ERR(acl);
  	if (acl == NULL)
  		return -ENODATA;
  	ret = posix_acl_to_xattr(acl, buffer, size);
  	posix_acl_release(acl);
  
  	return ret;
  }

  static int ocfs2_xattr_set_acl(struct dentry *dentry, const char *name,
  		const void *value, size_t size, int flags, int type)

  {

  	struct inode *inode = dentry->d_inode;

  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	struct posix_acl *acl;
  	int ret = 0;

  	if (strcmp(name, "") != 0)
  		return -EINVAL;

  	if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
  		return -EOPNOTSUPP;

  	if (!inode_owner_or_capable(inode))

  		return -EPERM;
  
  	if (value) {
  		acl = posix_acl_from_xattr(value, size);
  		if (IS_ERR(acl))
  			return PTR_ERR(acl);
  		else if (acl) {
  			ret = posix_acl_valid(acl);
  			if (ret)
  				goto cleanup;
  		}
  	} else
  		acl = NULL;
  
  	ret = ocfs2_set_acl(NULL, inode, NULL, type, acl, NULL, NULL);
  
  cleanup:
  	posix_acl_release(acl);
  	return ret;
  }

  const struct xattr_handler ocfs2_xattr_acl_access_handler = {

  	.prefix	= POSIX_ACL_XATTR_ACCESS,

  	.flags	= ACL_TYPE_ACCESS,

  	.list	= ocfs2_xattr_list_acl_access,

  	.get	= ocfs2_xattr_get_acl,
  	.set	= ocfs2_xattr_set_acl,

  };

  const struct xattr_handler ocfs2_xattr_acl_default_handler = {

  	.prefix	= POSIX_ACL_XATTR_DEFAULT,

  	.flags	= ACL_TYPE_DEFAULT,

  	.list	= ocfs2_xattr_list_acl_default,

  	.get	= ocfs2_xattr_get_acl,
  	.set	= ocfs2_xattr_set_acl,

  };