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1/*
2 File: linux/posix_acl.h
3
4 (C) 2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
5*/
6
7
8#ifndef __LINUX_POSIX_ACL_H
9#define __LINUX_POSIX_ACL_H
10
11#include <linux/slab.h>
12
13#define ACL_UNDEFINED_ID (-1)
14
15/* a_type field in acl_user_posix_entry_t */
16#define ACL_TYPE_ACCESS (0x8000)
17#define ACL_TYPE_DEFAULT (0x4000)
18
19/* e_tag entry in struct posix_acl_entry */
20#define ACL_USER_OBJ (0x01)
21#define ACL_USER (0x02)
22#define ACL_GROUP_OBJ (0x04)
23#define ACL_GROUP (0x08)
24#define ACL_MASK (0x10)
25#define ACL_OTHER (0x20)
26
27/* permissions in the e_perm field */
28#define ACL_READ (0x04)
29#define ACL_WRITE (0x02)
30#define ACL_EXECUTE (0x01)
31//#define ACL_ADD (0x08)
32//#define ACL_DELETE (0x10)
33
34struct posix_acl_entry {
35 short e_tag;
36 unsigned short e_perm;
37 unsigned int e_id;
38};
39
40struct posix_acl {
41 atomic_t a_refcount;
42 unsigned int a_count;
43 struct posix_acl_entry a_entries[0];
44};
45
46#define FOREACH_ACL_ENTRY(pa, acl, pe) \
47 for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)
48
49
50/*
51 * Duplicate an ACL handle.
52 */
53static inline struct posix_acl *
54posix_acl_dup(struct posix_acl *acl)
55{
56 if (acl)
57 atomic_inc(&acl->a_refcount);
58 return acl;
59}
60
61/*
62 * Free an ACL handle.
63 */
64static inline void
65posix_acl_release(struct posix_acl *acl)
66{
67 if (acl && atomic_dec_and_test(&acl->a_refcount))
68 kfree(acl);
69}
70
71
72/* posix_acl.c */
73
74extern void posix_acl_init(struct posix_acl *, int);
75extern struct posix_acl *posix_acl_alloc(int, gfp_t);
76extern struct posix_acl *posix_acl_clone(const struct posix_acl *, gfp_t);
77extern int posix_acl_valid(const struct posix_acl *);
78extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
79extern struct posix_acl *posix_acl_from_mode(mode_t, gfp_t);
80extern int posix_acl_equiv_mode(const struct posix_acl *, mode_t *);
81extern int posix_acl_create_masq(struct posix_acl *, mode_t *);
82extern int posix_acl_chmod_masq(struct posix_acl *, mode_t);
83
84extern struct posix_acl *get_posix_acl(struct inode *, int);
85extern int set_posix_acl(struct inode *, int, struct posix_acl *);
86
87#ifdef CONFIG_FS_POSIX_ACL
88static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
89{
90 struct posix_acl **p, *acl;
91 switch (type) {
92 case ACL_TYPE_ACCESS:
93 p = &inode->i_acl;
94 break;
95 case ACL_TYPE_DEFAULT:
96 p = &inode->i_default_acl;
97 break;
98 default:
99 return ERR_PTR(-EINVAL);
100 }
101 acl = ACCESS_ONCE(*p);
102 if (acl) {
103 spin_lock(&inode->i_lock);
104 acl = *p;
105 if (acl != ACL_NOT_CACHED)
106 acl = posix_acl_dup(acl);
107 spin_unlock(&inode->i_lock);
108 }
109 return acl;
110}
111
112static inline int negative_cached_acl(struct inode *inode, int type)
113{
114 struct posix_acl **p, *acl;
115 switch (type) {
116 case ACL_TYPE_ACCESS:
117 p = &inode->i_acl;
118 break;
119 case ACL_TYPE_DEFAULT:
120 p = &inode->i_default_acl;
121 break;
122 default:
123 BUG();
124 }
125 acl = ACCESS_ONCE(*p);
126 if (acl)
127 return 0;
128 return 1;
129}
130
131static inline void set_cached_acl(struct inode *inode,
132 int type,
133 struct posix_acl *acl)
134{
135 struct posix_acl *old = NULL;
136 spin_lock(&inode->i_lock);
137 switch (type) {
138 case ACL_TYPE_ACCESS:
139 old = inode->i_acl;
140 inode->i_acl = posix_acl_dup(acl);
141 break;
142 case ACL_TYPE_DEFAULT:
143 old = inode->i_default_acl;
144 inode->i_default_acl = posix_acl_dup(acl);
145 break;
146 }
147 spin_unlock(&inode->i_lock);
148 if (old != ACL_NOT_CACHED)
149 posix_acl_release(old);
150}
151
152static inline void forget_cached_acl(struct inode *inode, int type)
153{
154 struct posix_acl *old = NULL;
155 spin_lock(&inode->i_lock);
156 switch (type) {
157 case ACL_TYPE_ACCESS:
158 old = inode->i_acl;
159 inode->i_acl = ACL_NOT_CACHED;
160 break;
161 case ACL_TYPE_DEFAULT:
162 old = inode->i_default_acl;
163 inode->i_default_acl = ACL_NOT_CACHED;
164 break;
165 }
166 spin_unlock(&inode->i_lock);
167 if (old != ACL_NOT_CACHED)
168 posix_acl_release(old);
169}
170
171static inline void forget_all_cached_acls(struct inode *inode)
172{
173 struct posix_acl *old_access, *old_default;
174 spin_lock(&inode->i_lock);
175 old_access = inode->i_acl;
176 old_default = inode->i_default_acl;
177 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
178 spin_unlock(&inode->i_lock);
179 if (old_access != ACL_NOT_CACHED)
180 posix_acl_release(old_access);
181 if (old_default != ACL_NOT_CACHED)
182 posix_acl_release(old_default);
183}
184#endif
185
186static inline void cache_no_acl(struct inode *inode)
187{
188#ifdef CONFIG_FS_POSIX_ACL
189 inode->i_acl = NULL;
190 inode->i_default_acl = NULL;
191#endif
192}
193
194#endif /* __LINUX_POSIX_ACL_H */