Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
36struct 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
48struct 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 */
64static inline struct posix_acl *
65posix_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 */
75static inline void
76posix_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
85extern void posix_acl_init(struct posix_acl *, int);
86extern struct posix_acl *posix_acl_alloc(int, gfp_t);
87extern int posix_acl_valid(const struct posix_acl *);
88extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
89extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
90extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
91extern int posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
92extern int posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
93
94extern struct posix_acl *get_posix_acl(struct inode *, int);
95extern int set_posix_acl(struct inode *, int, struct posix_acl *);
96
97#ifdef CONFIG_FS_POSIX_ACL
98static 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
110static 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
124static 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
129static 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
143static 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
155static 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
170static 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 */