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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 * |
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 |
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 | |
94 | extern struct posix_acl *get_posix_acl(struct inode *, int); |
95 | extern int set_posix_acl(struct inode *, int, struct posix_acl *); |
96 | |
97 | #ifdef CONFIG_FS_POSIX_ACL |
98 | static 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 | |
110 | static 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 | |
124 | static 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 | |
129 | static 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 | |
143 | static 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 | |
155 | static 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 | |
170 | static 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 */ |
179 |
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