2 File: linux/posix_acl.h
4 (C) 2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
8 #ifndef __LINUX_POSIX_ACL_H
9 #define __LINUX_POSIX_ACL_H
11 #include <linux/slab.h>
12 #include <linux/rcupdate.h>
14 #define ACL_UNDEFINED_ID (-1)
16 /* a_type field in acl_user_posix_entry_t */
17 #define ACL_TYPE_ACCESS (0x8000)
18 #define ACL_TYPE_DEFAULT (0x4000)
20 /* e_tag entry in struct posix_acl_entry */
21 #define ACL_USER_OBJ (0x01)
22 #define ACL_USER (0x02)
23 #define ACL_GROUP_OBJ (0x04)
24 #define ACL_GROUP (0x08)
25 #define ACL_MASK (0x10)
26 #define ACL_OTHER (0x20)
28 /* permissions in the e_perm field */
29 #define ACL_READ (0x04)
30 #define ACL_WRITE (0x02)
31 #define ACL_EXECUTE (0x01)
32 //#define ACL_ADD (0x08)
33 //#define ACL_DELETE (0x10)
35 struct posix_acl_entry {
37 unsigned short e_perm;
44 struct rcu_head a_rcu;
47 struct posix_acl_entry a_entries[0];
50 #define FOREACH_ACL_ENTRY(pa, acl, pe) \
51 for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)
55 * Duplicate an ACL handle.
57 static inline struct posix_acl *
58 posix_acl_dup(struct posix_acl *acl)
61 atomic_inc(&acl->a_refcount);
69 posix_acl_release(struct posix_acl *acl)
71 if (acl && atomic_dec_and_test(&acl->a_refcount))
72 kfree_rcu(acl, a_rcu);
78 extern void posix_acl_init(struct posix_acl *, int);
79 extern struct posix_acl *posix_acl_alloc(int, gfp_t);
80 extern int posix_acl_valid(const struct posix_acl *);
81 extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
82 extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
83 extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
84 extern int posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
85 extern int posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
86 extern int posix_acl_update_mode(struct inode *, umode_t *, struct posix_acl **);
88 extern struct posix_acl *get_posix_acl(struct inode *, int);
89 extern int set_posix_acl(struct inode *, int, struct posix_acl *);
91 #ifdef CONFIG_FS_POSIX_ACL
92 static inline struct posix_acl **acl_by_type(struct inode *inode, int type)
97 case ACL_TYPE_DEFAULT:
98 return &inode->i_default_acl;
104 static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
106 struct posix_acl **p = acl_by_type(inode, type);
107 struct posix_acl *acl = ACCESS_ONCE(*p);
109 spin_lock(&inode->i_lock);
111 if (acl != ACL_NOT_CACHED)
112 acl = posix_acl_dup(acl);
113 spin_unlock(&inode->i_lock);
118 static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
120 return rcu_dereference(*acl_by_type(inode, type));
123 static inline void set_cached_acl(struct inode *inode,
125 struct posix_acl *acl)
127 struct posix_acl **p = acl_by_type(inode, type);
128 struct posix_acl *old;
129 spin_lock(&inode->i_lock);
131 rcu_assign_pointer(*p, posix_acl_dup(acl));
132 spin_unlock(&inode->i_lock);
133 if (old != ACL_NOT_CACHED)
134 posix_acl_release(old);
137 static inline void forget_cached_acl(struct inode *inode, int type)
139 struct posix_acl **p = acl_by_type(inode, type);
140 struct posix_acl *old;
141 spin_lock(&inode->i_lock);
144 spin_unlock(&inode->i_lock);
145 if (old != ACL_NOT_CACHED)
146 posix_acl_release(old);
149 static inline void forget_all_cached_acls(struct inode *inode)
151 struct posix_acl *old_access, *old_default;
152 spin_lock(&inode->i_lock);
153 old_access = inode->i_acl;
154 old_default = inode->i_default_acl;
155 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
156 spin_unlock(&inode->i_lock);
157 if (old_access != ACL_NOT_CACHED)
158 posix_acl_release(old_access);
159 if (old_default != ACL_NOT_CACHED)
160 posix_acl_release(old_default);
164 static inline void cache_no_acl(struct inode *inode)
166 #ifdef CONFIG_FS_POSIX_ACL
168 inode->i_default_acl = NULL;
172 #endif /* __LINUX_POSIX_ACL_H */