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 *
posix_acl_dup(struct posix_acl * 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
posix_acl_release(struct posix_acl * acl)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
get_cached_acl(struct inode * inode,int type)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
negative_cached_acl(struct inode * inode,int type)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
set_cached_acl(struct inode * inode,int type,struct posix_acl * acl)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
forget_cached_acl(struct inode * inode,int type)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
forget_all_cached_acls(struct inode * inode)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
cache_no_acl(struct inode * inode)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 */
195