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/slab.h>
12#include <linux/rcupdate.h>
13
14#define ACL_UNDEFINED_ID (-1)
15
16/* a_type field in acl_user_posix_entry_t */
17#define ACL_TYPE_ACCESS (0x8000)
18#define ACL_TYPE_DEFAULT (0x4000)
19
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)
27
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)
34
35struct posix_acl_entry {
36 short e_tag;
37 unsigned short e_perm;
38 unsigned int e_id;
39};
40
41struct posix_acl {
42 union {
43 atomic_t a_refcount;
44 struct rcu_head a_rcu;
45 };
46 unsigned int a_count;
47 struct posix_acl_entry a_entries[0];
48};
49
50#define FOREACH_ACL_ENTRY(pa, acl, pe) \
51 for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)
52
53
54/*
55 * Duplicate an ACL handle.
56 */
57static inline struct posix_acl *
58posix_acl_dup(struct posix_acl *acl)
59{
60 if (acl)
61 atomic_inc(&acl->a_refcount);
62 return acl;
63}
64
65/*
66 * Free an ACL handle.
67 */
68static inline void
69posix_acl_release(struct posix_acl *acl)
70{
71 if (acl && atomic_dec_and_test(&acl->a_refcount))
72 kfree_rcu(acl, a_rcu);
73}
74
75
76/* posix_acl.c */
77
78extern void posix_acl_init(struct posix_acl *, int);
79extern struct posix_acl *posix_acl_alloc(int, gfp_t);
80extern int posix_acl_valid(const struct posix_acl *);
81extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
82extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
83extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
84extern int posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
85extern int posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
86
87extern struct posix_acl *get_posix_acl(struct inode *, int);
88extern int set_posix_acl(struct inode *, int, struct posix_acl *);
89
90#ifdef CONFIG_FS_POSIX_ACL
91static inline struct posix_acl **acl_by_type(struct inode *inode, int type)
92{
93 switch (type) {
94 case ACL_TYPE_ACCESS:
95 return &inode->i_acl;
96 case ACL_TYPE_DEFAULT:
97 return &inode->i_default_acl;
98 default:
99 BUG();
100 }
101}
102
103static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
104{
105 struct posix_acl **p = acl_by_type(inode, type);
106 struct posix_acl *acl = ACCESS_ONCE(*p);
107 if (acl) {
108 spin_lock(&inode->i_lock);
109 acl = *p;
110 if (acl != ACL_NOT_CACHED)
111 acl = posix_acl_dup(acl);
112 spin_unlock(&inode->i_lock);
113 }
114 return acl;
115}
116
117static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
118{
119 return rcu_dereference(*acl_by_type(inode, type));
120}
121
122static inline void set_cached_acl(struct inode *inode,
123 int type,
124 struct posix_acl *acl)
125{
126 struct posix_acl **p = acl_by_type(inode, type);
127 struct posix_acl *old;
128 spin_lock(&inode->i_lock);
129 old = *p;
130 rcu_assign_pointer(*p, posix_acl_dup(acl));
131 spin_unlock(&inode->i_lock);
132 if (old != ACL_NOT_CACHED)
133 posix_acl_release(old);
134}
135
136static inline void forget_cached_acl(struct inode *inode, int type)
137{
138 struct posix_acl **p = acl_by_type(inode, type);
139 struct posix_acl *old;
140 spin_lock(&inode->i_lock);
141 old = *p;
142 *p = ACL_NOT_CACHED;
143 spin_unlock(&inode->i_lock);
144 if (old != ACL_NOT_CACHED)
145 posix_acl_release(old);
146}
147
148static inline void forget_all_cached_acls(struct inode *inode)
149{
150 struct posix_acl *old_access, *old_default;
151 spin_lock(&inode->i_lock);
152 old_access = inode->i_acl;
153 old_default = inode->i_default_acl;
154 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
155 spin_unlock(&inode->i_lock);
156 if (old_access != ACL_NOT_CACHED)
157 posix_acl_release(old_access);
158 if (old_default != ACL_NOT_CACHED)
159 posix_acl_release(old_default);
160}
161#endif
162
163static inline void cache_no_acl(struct inode *inode)
164{
165#ifdef CONFIG_FS_POSIX_ACL
166 inode->i_acl = NULL;
167 inode->i_default_acl = NULL;
168#endif
169}
170
171#endif /* __LINUX_POSIX_ACL_H */