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