Merge branch 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
[linux-2.6.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 struct posix_acl *posix_acl_clone(const struct posix_acl *, gfp_t);
77 extern int posix_acl_valid(const struct posix_acl *);
78 extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
79 extern struct posix_acl *posix_acl_from_mode(mode_t, gfp_t);
80 extern int posix_acl_equiv_mode(const struct posix_acl *, mode_t *);
81 extern int posix_acl_create_masq(struct posix_acl *, mode_t *);
82 extern int posix_acl_chmod_masq(struct posix_acl *, mode_t);
83
84 extern struct posix_acl *get_posix_acl(struct inode *, int);
85 extern int set_posix_acl(struct inode *, int, struct posix_acl *);
86
87 #ifdef CONFIG_FS_POSIX_ACL
88 static 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
112 static 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
131 static 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
152 static 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
171 static 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
186 static 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 */