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 *
posix_acl_dup(struct posix_acl * 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
posix_acl_release(struct posix_acl * acl)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 extern int posix_acl_update_mode(struct inode *, umode_t *, struct posix_acl **);
94
95 extern struct posix_acl *get_posix_acl(struct inode *, int);
96 extern int set_posix_acl(struct inode *, int, struct posix_acl *);
97
98 #ifdef CONFIG_FS_POSIX_ACL
acl_by_type(struct inode * inode,int type)99 static inline struct posix_acl **acl_by_type(struct inode *inode, int type)
100 {
101 switch (type) {
102 case ACL_TYPE_ACCESS:
103 return &inode->i_acl;
104 case ACL_TYPE_DEFAULT:
105 return &inode->i_default_acl;
106 default:
107 BUG();
108 }
109 }
110
get_cached_acl(struct inode * inode,int type)111 static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
112 {
113 struct posix_acl **p = acl_by_type(inode, type);
114 struct posix_acl *acl = ACCESS_ONCE(*p);
115 if (acl) {
116 spin_lock(&inode->i_lock);
117 acl = *p;
118 if (acl != ACL_NOT_CACHED)
119 acl = posix_acl_dup(acl);
120 spin_unlock(&inode->i_lock);
121 }
122 return acl;
123 }
124
get_cached_acl_rcu(struct inode * inode,int type)125 static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
126 {
127 return rcu_dereference(*acl_by_type(inode, type));
128 }
129
set_cached_acl(struct inode * inode,int type,struct posix_acl * acl)130 static inline void set_cached_acl(struct inode *inode,
131 int type,
132 struct posix_acl *acl)
133 {
134 struct posix_acl **p = acl_by_type(inode, type);
135 struct posix_acl *old;
136 spin_lock(&inode->i_lock);
137 old = *p;
138 rcu_assign_pointer(*p, posix_acl_dup(acl));
139 spin_unlock(&inode->i_lock);
140 if (old != ACL_NOT_CACHED)
141 posix_acl_release(old);
142 }
143
forget_cached_acl(struct inode * inode,int type)144 static inline void forget_cached_acl(struct inode *inode, int type)
145 {
146 struct posix_acl **p = acl_by_type(inode, type);
147 struct posix_acl *old;
148 spin_lock(&inode->i_lock);
149 old = *p;
150 *p = ACL_NOT_CACHED;
151 spin_unlock(&inode->i_lock);
152 if (old != ACL_NOT_CACHED)
153 posix_acl_release(old);
154 }
155
forget_all_cached_acls(struct inode * inode)156 static inline void forget_all_cached_acls(struct inode *inode)
157 {
158 struct posix_acl *old_access, *old_default;
159 spin_lock(&inode->i_lock);
160 old_access = inode->i_acl;
161 old_default = inode->i_default_acl;
162 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
163 spin_unlock(&inode->i_lock);
164 if (old_access != ACL_NOT_CACHED)
165 posix_acl_release(old_access);
166 if (old_default != ACL_NOT_CACHED)
167 posix_acl_release(old_default);
168 }
169 #endif
170
cache_no_acl(struct inode * inode)171 static inline void cache_no_acl(struct inode *inode)
172 {
173 #ifdef CONFIG_FS_POSIX_ACL
174 inode->i_acl = NULL;
175 inode->i_default_acl = NULL;
176 #endif
177 }
178
179 #endif /* __LINUX_POSIX_ACL_H */
180