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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 | extern int posix_acl_chmod(struct inode *); | |
99 | ||
100 | static inline struct posix_acl **acl_by_type(struct inode *inode, int type) | |
101 | { | |
102 | switch (type) { | |
103 | case ACL_TYPE_ACCESS: | |
104 | return &inode->i_acl; | |
105 | case ACL_TYPE_DEFAULT: | |
106 | return &inode->i_default_acl; | |
107 | default: | |
108 | BUG(); | |
109 | } | |
110 | } | |
111 | ||
112 | static inline struct posix_acl *get_cached_acl(struct inode *inode, int type) | |
113 | { | |
114 | struct posix_acl **p = acl_by_type(inode, type); | |
115 | struct posix_acl *acl = ACCESS_ONCE(*p); | |
116 | if (acl) { | |
117 | spin_lock(&inode->i_lock); | |
118 | acl = *p; | |
119 | if (acl != ACL_NOT_CACHED) | |
120 | acl = posix_acl_dup(acl); | |
121 | spin_unlock(&inode->i_lock); | |
122 | } | |
123 | return acl; | |
124 | } | |
125 | ||
126 | static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) | |
127 | { | |
128 | return rcu_dereference(*acl_by_type(inode, type)); | |
129 | } | |
130 | ||
131 | static inline void set_cached_acl(struct inode *inode, | |
132 | int type, | |
133 | struct posix_acl *acl) | |
134 | { | |
135 | struct posix_acl **p = acl_by_type(inode, type); | |
136 | struct posix_acl *old; | |
137 | spin_lock(&inode->i_lock); | |
138 | old = *p; | |
139 | rcu_assign_pointer(*p, posix_acl_dup(acl)); | |
140 | spin_unlock(&inode->i_lock); | |
141 | if (old != ACL_NOT_CACHED) | |
142 | posix_acl_release(old); | |
143 | } | |
144 | ||
145 | static inline void forget_cached_acl(struct inode *inode, int type) | |
146 | { | |
147 | struct posix_acl **p = acl_by_type(inode, type); | |
148 | struct posix_acl *old; | |
149 | spin_lock(&inode->i_lock); | |
150 | old = *p; | |
151 | *p = ACL_NOT_CACHED; | |
152 | spin_unlock(&inode->i_lock); | |
153 | if (old != ACL_NOT_CACHED) | |
154 | posix_acl_release(old); | |
155 | } | |
156 | ||
157 | static inline void forget_all_cached_acls(struct inode *inode) | |
158 | { | |
159 | struct posix_acl *old_access, *old_default; | |
160 | spin_lock(&inode->i_lock); | |
161 | old_access = inode->i_acl; | |
162 | old_default = inode->i_default_acl; | |
163 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; | |
164 | spin_unlock(&inode->i_lock); | |
165 | if (old_access != ACL_NOT_CACHED) | |
166 | posix_acl_release(old_access); | |
167 | if (old_default != ACL_NOT_CACHED) | |
168 | posix_acl_release(old_default); | |
169 | } | |
170 | ||
171 | static inline void cache_no_acl(struct inode *inode) | |
172 | { | |
173 | inode->i_acl = NULL; | |
174 | inode->i_default_acl = NULL; | |
175 | } | |
176 | #else | |
177 | static inline int posix_acl_chmod(struct inode *inode) | |
178 | { | |
179 | return 0; | |
180 | } | |
181 | ||
182 | static inline void cache_no_acl(struct inode *inode) | |
183 | { | |
184 | } | |
185 | #endif /* CONFIG_FS_POSIX_ACL */ | |
186 | ||
187 | struct posix_acl *get_acl(struct inode *inode, int type); | |
188 | ||
189 | #endif /* __LINUX_POSIX_ACL_H */ |