9a53b99818e28d2302cd004eaf7ef0f05005d1af
[linux-3.10.git] / include / linux / posix_acl.h
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
34 struct posix_acl_entry {
35         short                   e_tag;
36         unsigned short          e_perm;
37         unsigned int            e_id;
38 };
39
40 struct 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  */
53 static inline struct posix_acl *
54 posix_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  */
64 static inline void
65 posix_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
74 extern void posix_acl_init(struct posix_acl *, int);
75 extern struct posix_acl *posix_acl_alloc(int, gfp_t);
76 extern int posix_acl_valid(const struct posix_acl *);
77 extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
78 extern struct posix_acl *posix_acl_from_mode(mode_t, gfp_t);
79 extern int posix_acl_equiv_mode(const struct posix_acl *, mode_t *);
80 extern int posix_acl_create(struct posix_acl **, gfp_t, mode_t *);
81 extern int posix_acl_chmod(struct posix_acl **, gfp_t, mode_t);
82
83 extern struct posix_acl *get_posix_acl(struct inode *, int);
84 extern int set_posix_acl(struct inode *, int, struct posix_acl *);
85
86 #ifdef CONFIG_FS_POSIX_ACL
87 static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
88 {
89         struct posix_acl **p, *acl;
90         switch (type) {
91         case ACL_TYPE_ACCESS:
92                 p = &inode->i_acl;
93                 break;
94         case ACL_TYPE_DEFAULT:
95                 p = &inode->i_default_acl;
96                 break;
97         default:
98                 return ERR_PTR(-EINVAL);
99         }
100         acl = ACCESS_ONCE(*p);
101         if (acl) {
102                 spin_lock(&inode->i_lock);
103                 acl = *p;
104                 if (acl != ACL_NOT_CACHED)
105                         acl = posix_acl_dup(acl);
106                 spin_unlock(&inode->i_lock);
107         }
108         return acl;
109 }
110
111 static inline int negative_cached_acl(struct inode *inode, int type)
112 {
113         struct posix_acl **p, *acl;
114         switch (type) {
115         case ACL_TYPE_ACCESS:
116                 p = &inode->i_acl;
117                 break;
118         case ACL_TYPE_DEFAULT:
119                 p = &inode->i_default_acl;
120                 break;
121         default:
122                 BUG();
123         }
124         acl = ACCESS_ONCE(*p);
125         if (acl)
126                 return 0;
127         return 1;
128 }
129
130 static inline void set_cached_acl(struct inode *inode,
131                                   int type,
132                                   struct posix_acl *acl)
133 {
134         struct posix_acl *old = NULL;
135         spin_lock(&inode->i_lock);
136         switch (type) {
137         case ACL_TYPE_ACCESS:
138                 old = inode->i_acl;
139                 inode->i_acl = posix_acl_dup(acl);
140                 break;
141         case ACL_TYPE_DEFAULT:
142                 old = inode->i_default_acl;
143                 inode->i_default_acl = posix_acl_dup(acl);
144                 break;
145         }
146         spin_unlock(&inode->i_lock);
147         if (old != ACL_NOT_CACHED)
148                 posix_acl_release(old);
149 }
150
151 static inline void forget_cached_acl(struct inode *inode, int type)
152 {
153         struct posix_acl *old = NULL;
154         spin_lock(&inode->i_lock);
155         switch (type) {
156         case ACL_TYPE_ACCESS:
157                 old = inode->i_acl;
158                 inode->i_acl = ACL_NOT_CACHED;
159                 break;
160         case ACL_TYPE_DEFAULT:
161                 old = inode->i_default_acl;
162                 inode->i_default_acl = ACL_NOT_CACHED;
163                 break;
164         }
165         spin_unlock(&inode->i_lock);
166         if (old != ACL_NOT_CACHED)
167                 posix_acl_release(old);
168 }
169
170 static inline void forget_all_cached_acls(struct inode *inode)
171 {
172         struct posix_acl *old_access, *old_default;
173         spin_lock(&inode->i_lock);
174         old_access = inode->i_acl;
175         old_default = inode->i_default_acl;
176         inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
177         spin_unlock(&inode->i_lock);
178         if (old_access != ACL_NOT_CACHED)
179                 posix_acl_release(old_access);
180         if (old_default != ACL_NOT_CACHED)
181                 posix_acl_release(old_default);
182 }
183 #endif
184
185 static inline void cache_no_acl(struct inode *inode)
186 {
187 #ifdef CONFIG_FS_POSIX_ACL
188         inode->i_acl = NULL;
189         inode->i_default_acl = NULL;
190 #endif
191 }
192
193 #endif  /* __LINUX_POSIX_ACL_H */