/*

   * linux/fs/ext4/acl.c

   *
   * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
   */

  #include "ext4_jbd2.h"
  #include "ext4.h"

  #include "xattr.h"
  #include "acl.h"
  
  /*
   * Convert from filesystem to in-memory representation.
   */
  static struct posix_acl *

  ext4_acl_from_disk(const void *value, size_t size)

  {
  	const char *end = (char *)value + size;
  	int n, count;
  	struct posix_acl *acl;
  
  	if (!value)
  		return NULL;

  	if (size < sizeof(ext4_acl_header))

  		 return ERR_PTR(-EINVAL);

  	if (((ext4_acl_header *)value)->a_version !=
  	    cpu_to_le32(EXT4_ACL_VERSION))

  		return ERR_PTR(-EINVAL);

  	value = (char *)value + sizeof(ext4_acl_header);
  	count = ext4_acl_count(size);

  	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++) {

  		ext4_acl_entry *entry =
  			(ext4_acl_entry *)value;
  		if ((char *)value + sizeof(ext4_acl_entry_short) > end)

  			goto fail;
  		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
  		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);

  
  		switch (acl->a_entries[n].e_tag) {
  		case ACL_USER_OBJ:
  		case ACL_GROUP_OBJ:
  		case ACL_MASK:
  		case ACL_OTHER:
  			value = (char *)value +
  				sizeof(ext4_acl_entry_short);

  			break;
  
  		case ACL_USER:

  			value = (char *)value + sizeof(ext4_acl_entry);
  			if ((char *)value > end)
  				goto fail;
  			acl->a_entries[n].e_uid =
  				make_kuid(&init_user_ns,
  					  le32_to_cpu(entry->e_id));
  			break;

  		case ACL_GROUP:
  			value = (char *)value + sizeof(ext4_acl_entry);
  			if ((char *)value > end)

  				goto fail;

  			acl->a_entries[n].e_gid =
  				make_kgid(&init_user_ns,
  					  le32_to_cpu(entry->e_id));

  			break;
  
  		default:
  			goto fail;

  		}
  	}
  	if (value != end)
  		goto fail;
  	return acl;
  
  fail:
  	posix_acl_release(acl);
  	return ERR_PTR(-EINVAL);
  }
  
  /*
   * Convert from in-memory to filesystem representation.
   */
  static void *

  ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)

  {

  	ext4_acl_header *ext_acl;

  	char *e;
  	size_t n;

  	*size = ext4_acl_size(acl->a_count);
  	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *

  			sizeof(ext4_acl_entry), GFP_NOFS);

  	if (!ext_acl)
  		return ERR_PTR(-ENOMEM);

  	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
  	e = (char *)ext_acl + sizeof(ext4_acl_header);

  	for (n = 0; n < acl->a_count; n++) {

  		const struct posix_acl_entry *acl_e = &acl->a_entries[n];

  		ext4_acl_entry *entry = (ext4_acl_entry *)e;

  		entry->e_tag  = cpu_to_le16(acl_e->e_tag);
  		entry->e_perm = cpu_to_le16(acl_e->e_perm);
  		switch (acl_e->e_tag) {

  		case ACL_USER:

  			entry->e_id = cpu_to_le32(
  				from_kuid(&init_user_ns, acl_e->e_uid));
  			e += sizeof(ext4_acl_entry);
  			break;

  		case ACL_GROUP:

  			entry->e_id = cpu_to_le32(
  				from_kgid(&init_user_ns, acl_e->e_gid));

  			e += sizeof(ext4_acl_entry);
  			break;
  
  		case ACL_USER_OBJ:
  		case ACL_GROUP_OBJ:
  		case ACL_MASK:
  		case ACL_OTHER:
  			e += sizeof(ext4_acl_entry_short);
  			break;
  
  		default:
  			goto fail;

  		}
  	}
  	return (char *)ext_acl;
  
  fail:
  	kfree(ext_acl);
  	return ERR_PTR(-EINVAL);
  }

  /*
   * Inode operation get_posix_acl().
   *
   * inode->i_mutex: don't care
   */

  struct posix_acl *

  ext4_get_acl(struct inode *inode, int type)

  {

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

  	switch (type) {
  	case ACL_TYPE_ACCESS:

  		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
  		break;

  	case ACL_TYPE_DEFAULT:

  		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
  		break;

  	default:

  		BUG();

  	}

  	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);

  	if (retval > 0) {

  		value = kmalloc(retval, GFP_NOFS);

  		if (!value)
  			return ERR_PTR(-ENOMEM);

  		retval = ext4_xattr_get(inode, name_index, "", value, retval);

  	}
  	if (retval > 0)

  		acl = ext4_acl_from_disk(value, retval);

  	else if (retval == -ENODATA || retval == -ENOSYS)
  		acl = NULL;
  	else
  		acl = ERR_PTR(retval);
  	kfree(value);

  	return acl;
  }
  
  /*
   * Set the access or default ACL of an inode.
   *

   * inode->i_mutex: down unless called from ext4_new_inode

   */
  static int

  __ext4_set_acl(handle_t *handle, struct inode *inode, int type,

  	     struct posix_acl *acl)
  {

  	int name_index;
  	void *value = NULL;
  	size_t size = 0;
  	int error;

  	switch (type) {
  	case ACL_TYPE_ACCESS:
  		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
  		if (acl) {

  			error = posix_acl_update_mode(inode, &inode->i_mode, &acl);
  			if (error)

  				return error;

  			inode->i_ctime = ext4_current_time(inode);
  			ext4_mark_inode_dirty(handle, inode);

  		}
  		break;

  	case ACL_TYPE_DEFAULT:
  		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
  		if (!S_ISDIR(inode->i_mode))
  			return acl ? -EACCES : 0;
  		break;

  	default:
  		return -EINVAL;

  	}
  	if (acl) {

  		value = ext4_acl_to_disk(acl, &size);

  		if (IS_ERR(value))
  			return (int)PTR_ERR(value);
  	}

  	error = ext4_xattr_set_handle(handle, inode, name_index, "",

  				      value, size, 0);
  
  	kfree(value);

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

  	return error;
  }

  int

  ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)

  {

  	handle_t *handle;

  	int error, retries = 0;

  retry:

  	handle = ext4_journal_start(inode, EXT4_HT_XATTR,

  				    ext4_jbd2_credits_xattr(inode));

  	if (IS_ERR(handle))
  		return PTR_ERR(handle);
  
  	error = __ext4_set_acl(handle, inode, type, acl);

  	ext4_journal_stop(handle);

  	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))

  		goto retry;

  	return error;
  }
  
  /*

   * Initialize the ACLs of a new inode. Called from ext4_new_inode.
   *
   * dir->i_mutex: down
   * inode->i_mutex: up (access to inode is still exclusive)

   */

  int
  ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)

  {

  	struct posix_acl *default_acl, *acl;

  	int error;

  	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
  	if (error)
  		return error;

  	if (default_acl) {
  		error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
  				       default_acl);
  		posix_acl_release(default_acl);
  	}
  	if (acl) {
  		if (!error)
  			error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
  					       acl);
  		posix_acl_release(acl);

  	}

  	return error;
  }