1/*
2 * linux/fs/xattr_acl.c
3 *
4 * Almost all from linux/fs/ext2/acl.c:
5 * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
6 */
7
8#include <linux/module.h>
9#include <linux/slab.h>
10#include <linux/fs.h>
11#include <linux/posix_acl_xattr.h>
12
13
14/*
15 * Convert from extended attribute to in-memory representation.
16 */
17struct posix_acl *
18posix_acl_from_xattr(const void *value, size_t size)
19{
20	posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
21	posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
22	int count;
23	struct posix_acl *acl;
24	struct posix_acl_entry *acl_e;
25
26	if (!value)
27		return NULL;
28	if (size < sizeof(posix_acl_xattr_header))
29		 return ERR_PTR(-EINVAL);
30	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
31		return ERR_PTR(-EOPNOTSUPP);
32
33	count = posix_acl_xattr_count(size);
34	if (count < 0)
35		return ERR_PTR(-EINVAL);
36	if (count == 0)
37		return NULL;
38
39	acl = posix_acl_alloc(count, GFP_KERNEL);
40	if (!acl)
41		return ERR_PTR(-ENOMEM);
42	acl_e = acl->a_entries;
43
44	for (end = entry + count; entry != end; acl_e++, entry++) {
45		acl_e->e_tag  = le16_to_cpu(entry->e_tag);
46		acl_e->e_perm = le16_to_cpu(entry->e_perm);
47
48		switch(acl_e->e_tag) {
49			case ACL_USER_OBJ:
50			case ACL_GROUP_OBJ:
51			case ACL_MASK:
52			case ACL_OTHER:
53				acl_e->e_id = ACL_UNDEFINED_ID;
54				break;
55
56			case ACL_USER:
57			case ACL_GROUP:
58				acl_e->e_id = le32_to_cpu(entry->e_id);
59				break;
60
61			default:
62				goto fail;
63		}
64	}
65	return acl;
66
67fail:
68	posix_acl_release(acl);
69	return ERR_PTR(-EINVAL);
70}
71EXPORT_SYMBOL (posix_acl_from_xattr);
72
73/*
74 * Convert from in-memory to extended attribute representation.
75 */
76int
77posix_acl_to_xattr(const struct posix_acl *acl, void *buffer, size_t size)
78{
79	posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
80	posix_acl_xattr_entry *ext_entry = ext_acl->a_entries;
81	int real_size, n;
82
83	real_size = posix_acl_xattr_size(acl->a_count);
84	if (!buffer)
85		return real_size;
86	if (real_size > size)
87		return -ERANGE;
88
89	ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
90
91	for (n=0; n < acl->a_count; n++, ext_entry++) {
92		ext_entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
93		ext_entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
94		ext_entry->e_id   = cpu_to_le32(acl->a_entries[n].e_id);
95	}
96	return real_size;
97}
98EXPORT_SYMBOL (posix_acl_to_xattr);
99