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/bug.h>
12 #include <linux/slab.h>
13 #include <linux/rcupdate.h>
15 #define ACL_UNDEFINED_ID (-1)
17 /* a_type field in acl_user_posix_entry_t */
18 #define ACL_TYPE_ACCESS (0x8000)
19 #define ACL_TYPE_DEFAULT (0x4000)
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)
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)
36 struct posix_acl_entry {
38 unsigned short e_perm;
48 struct rcu_head a_rcu;
51 struct posix_acl_entry a_entries[0];
54 #define FOREACH_ACL_ENTRY(pa, acl, pe) \
55 for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)
59 * Duplicate an ACL handle.
61 static inline struct posix_acl *
62 posix_acl_dup(struct posix_acl *acl)
65 atomic_inc(&acl->a_refcount);
73 posix_acl_release(struct posix_acl *acl)
75 if (acl && atomic_dec_and_test(&acl->a_refcount))
76 kfree_rcu(acl, a_rcu);
82 extern void posix_acl_init(struct posix_acl *, int);
83 extern struct posix_acl *posix_acl_alloc(int, gfp_t);
84 extern int posix_acl_valid(const struct posix_acl *);
85 extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
86 extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
87 extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
88 extern int posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
89 extern int posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
91 extern struct posix_acl *get_posix_acl(struct inode *, int);
92 extern int set_posix_acl(struct inode *, int, struct posix_acl *);
94 #ifdef CONFIG_FS_POSIX_ACL
95 static inline struct posix_acl **acl_by_type(struct inode *inode, int type)
100 case ACL_TYPE_DEFAULT:
101 return &inode->i_default_acl;
107 static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
109 struct posix_acl **p = acl_by_type(inode, type);
110 struct posix_acl *acl = ACCESS_ONCE(*p);
112 spin_lock(&inode->i_lock);
114 if (acl != ACL_NOT_CACHED)
115 acl = posix_acl_dup(acl);
116 spin_unlock(&inode->i_lock);
121 static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
123 return rcu_dereference(*acl_by_type(inode, type));
126 static inline void set_cached_acl(struct inode *inode,
128 struct posix_acl *acl)
130 struct posix_acl **p = acl_by_type(inode, type);
131 struct posix_acl *old;
132 spin_lock(&inode->i_lock);
134 rcu_assign_pointer(*p, posix_acl_dup(acl));
135 spin_unlock(&inode->i_lock);
136 if (old != ACL_NOT_CACHED)
137 posix_acl_release(old);
140 static inline void forget_cached_acl(struct inode *inode, int type)
142 struct posix_acl **p = acl_by_type(inode, type);
143 struct posix_acl *old;
144 spin_lock(&inode->i_lock);
147 spin_unlock(&inode->i_lock);
148 if (old != ACL_NOT_CACHED)
149 posix_acl_release(old);
152 static inline void forget_all_cached_acls(struct inode *inode)
154 struct posix_acl *old_access, *old_default;
155 spin_lock(&inode->i_lock);
156 old_access = inode->i_acl;
157 old_default = inode->i_default_acl;
158 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
159 spin_unlock(&inode->i_lock);
160 if (old_access != ACL_NOT_CACHED)
161 posix_acl_release(old_access);
162 if (old_default != ACL_NOT_CACHED)
163 posix_acl_release(old_default);
167 static inline void cache_no_acl(struct inode *inode)
169 #ifdef CONFIG_FS_POSIX_ACL
171 inode->i_default_acl = NULL;
175 #endif /* __LINUX_POSIX_ACL_H */