summaryrefslogtreecommitdiff
path: root/mm/shmem_acl.c
blob: f5664c5b9eb1433425501486562c3c6bb98b2237 (plain) (blame)
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
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
/*
 * mm/shmem_acl.c
 *
 * (C) 2005 Andreas Gruenbacher <agruen@suse.de>
 *
 * This file is released under the GPL.
 */

#include <linux/fs.h>
#include <linux/shmem_fs.h>
#include <linux/xattr.h>
#include <linux/generic_acl.h>

/**
 * shmem_get_acl  -   generic_acl_operations->getacl() operation
 */
static struct posix_acl *
shmem_get_acl(struct inode *inode, int type)
{
	struct posix_acl *acl = NULL;

	spin_lock(&inode->i_lock);
	switch(type) {
		case ACL_TYPE_ACCESS:
			acl = posix_acl_dup(SHMEM_I(inode)->i_acl);
			break;

		case ACL_TYPE_DEFAULT:
			acl = posix_acl_dup(SHMEM_I(inode)->i_default_acl);
			break;
	}
	spin_unlock(&inode->i_lock);

	return acl;
}

/**
 * shmem_set_acl  -   generic_acl_operations->setacl() operation
 */
static void
shmem_set_acl(struct inode *inode, int type, struct posix_acl *acl)
{
	struct posix_acl *free = NULL;

	spin_lock(&inode->i_lock);
	switch(type) {
		case ACL_TYPE_ACCESS:
			free = SHMEM_I(inode)->i_acl;
			SHMEM_I(inode)->i_acl = posix_acl_dup(acl);
			break;

		case ACL_TYPE_DEFAULT:
			free = SHMEM_I(inode)->i_default_acl;
			SHMEM_I(inode)->i_default_acl = posix_acl_dup(acl);
			break;
	}
	spin_unlock(&inode->i_lock);
	posix_acl_release(free);
}

struct generic_acl_operations shmem_acl_ops = {
	.getacl = shmem_get_acl,
	.setacl = shmem_set_acl,
};

/**
 * shmem_list_acl_access, shmem_get_acl_access, shmem_set_acl_access,
 * shmem_xattr_acl_access_handler  -  plumbing code to implement the
 * system.posix_acl_access xattr using the generic acl functions.
 */

static size_t
shmem_list_acl_access(struct inode *inode, char *list, size_t list_size,
		      const char *name, size_t name_len)
{
	return generic_acl_list(inode, &shmem_acl_ops, ACL_TYPE_ACCESS,
				list, list_size);
}

static int
shmem_get_acl_access(struct inode *inode, const char *name, void *buffer,
		     size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return generic_acl_get(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, buffer,
			       size);
}

static int
shmem_set_acl_access(struct inode *inode, const char *name, const void *value,
		     size_t size, int flags)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return generic_acl_set(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, value,
			       size);
}

struct xattr_handler shmem_xattr_acl_access_handler = {
	.prefix = POSIX_ACL_XATTR_ACCESS,
	.list	= shmem_list_acl_access,
	.get	= shmem_get_acl_access,
	.set	= shmem_set_acl_access,
};

/**
 * shmem_list_acl_default, shmem_get_acl_default, shmem_set_acl_default,
 * shmem_xattr_acl_default_handler  -  plumbing code to implement the
 * system.posix_acl_default xattr using the generic acl functions.
 */

static size_t
shmem_list_acl_default(struct inode *inode, char *list, size_t list_size,
		       const char *name, size_t name_len)
{
	return generic_acl_list(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT,
				list, list_size);
}

static int
shmem_get_acl_default(struct inode *inode, const char *name, void *buffer,
		      size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return generic_acl_get(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, buffer,
			       size);
}

static int
shmem_set_acl_default(struct inode *inode, const char *name, const void *value,
		      size_t size, int flags)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return generic_acl_set(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, value,
			       size);
}

struct xattr_handler shmem_xattr_acl_default_handler = {
	.prefix = POSIX_ACL_XATTR_DEFAULT,
	.list	= shmem_list_acl_default,
	.get	= shmem_get_acl_default,
	.set	= shmem_set_acl_default,
};

/**
 * shmem_acl_init  -  Inizialize the acl(s) of a new inode
 */
int
shmem_acl_init(struct inode *inode, struct inode *dir)
{
	return generic_acl_init(inode, dir, &shmem_acl_ops);
}

/**
 * shmem_acl_destroy_inode  -  destroy acls hanging off the in-memory inode
 *
 * This is done before destroying the actual inode.
 */

void
shmem_acl_destroy_inode(struct inode *inode)
{
	if (SHMEM_I(inode)->i_acl)
		posix_acl_release(SHMEM_I(inode)->i_acl);
	SHMEM_I(inode)->i_acl = NULL;
	if (SHMEM_I(inode)->i_default_acl)
		posix_acl_release(SHMEM_I(inode)->i_default_acl);
	SHMEM_I(inode)->i_default_acl = NULL;
}

/**
 * shmem_check_acl  -  check_acl() callback for generic_permission()
 */
static int
shmem_check_acl(struct inode *inode, int mask)
{
	struct posix_acl *acl = shmem_get_acl(inode, ACL_TYPE_ACCESS);

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

/**
 * shmem_permission  -  permission() inode operation
 */
int
shmem_permission(struct inode *inode, int mask, struct nameidata *nd)
{
	return generic_permission(inode, mask, shmem_check_acl);
}