summaryrefslogtreecommitdiffstats
path: root/fs/9p/acl.c
blob: a8c013615a22b6b2e7232018077ff4562f100150 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
/*
 * Copyright IBM Corporation, 2010
 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2.1 of the GNU Lesser General Public License
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include <linux/slab.h>
#include <linux/posix_acl_xattr.h>
#include "xattr.h"
#include "acl.h"

static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name)
{
	ssize_t size;
	void *value = NULL;
	struct posix_acl *acl = NULL;;

	size = v9fs_fid_xattr_get(fid, name, NULL, 0);
	if (size > 0) {
		value = kzalloc(size, GFP_NOFS);
		if (!value)
			return ERR_PTR(-ENOMEM);
		size = v9fs_fid_xattr_get(fid, name, value, size);
		if (size > 0) {
			acl = posix_acl_from_xattr(value, size);
			if (IS_ERR(acl))
				goto err_out;
		}
	} else if (size == -ENODATA || size == 0 ||
		   size == -ENOSYS || size == -EOPNOTSUPP) {
		acl = NULL;
	} else
		acl = ERR_PTR(-EIO);

err_out:
	kfree(value);
	return acl;
}

int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
{
	int retval = 0;
	struct posix_acl *pacl, *dacl;

	/* get the default/access acl values and cache them */
	dacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_DEFAULT);
	pacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_ACCESS);

	if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
		set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
		set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
		posix_acl_release(dacl);
		posix_acl_release(pacl);
	} else
		retval = -EIO;

	return retval;
}

static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
{
	struct posix_acl *acl;
	/*
	 * 9p Always cache the acl value when
	 * instantiating the inode (v9fs_inode_from_fid)
	 */
	acl = get_cached_acl(inode, type);
	BUG_ON(acl == ACL_NOT_CACHED);
	return acl;
}

int v9fs_check_acl(struct inode *inode, int mask)
{
	struct posix_acl *acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);

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