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 13 #define ACL_UNDEFINED_ID (-1) 14 15 /* a_type field in acl_user_posix_entry_t */ 16 #define ACL_TYPE_ACCESS (0x8000) 17 #define ACL_TYPE_DEFAULT (0x4000) 18 19 /* e_tag entry in struct posix_acl_entry */ 20 #define ACL_USER_OBJ (0x01) 21 #define ACL_USER (0x02) 22 #define ACL_GROUP_OBJ (0x04) 23 #define ACL_GROUP (0x08) 24 #define ACL_MASK (0x10) 25 #define ACL_OTHER (0x20) 26 27 /* permissions in the e_perm field */ 28 #define ACL_READ (0x04) 29 #define ACL_WRITE (0x02) 30 #define ACL_EXECUTE (0x01) 31 //#define ACL_ADD (0x08) 32 //#define ACL_DELETE (0x10) 33 34 struct posix_acl_entry { 35 short e_tag; 36 unsigned short e_perm; 37 unsigned int e_id; 38 }; 39 40 struct posix_acl { 41 atomic_t a_refcount; 42 unsigned int a_count; 43 struct posix_acl_entry a_entries[0]; 44 }; 45 46 #define FOREACH_ACL_ENTRY(pa, acl, pe) \ 47 for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++) 48 49 50 /* 51 * Duplicate an ACL handle. 52 */ 53 static inline struct posix_acl * 54 posix_acl_dup(struct posix_acl *acl) 55 { 56 if (acl) 57 atomic_inc(&acl->a_refcount); 58 return acl; 59 } 60 61 /* 62 * Free an ACL handle. 63 */ 64 static inline void 65 posix_acl_release(struct posix_acl *acl) 66 { 67 if (acl && atomic_dec_and_test(&acl->a_refcount)) 68 kfree(acl); 69 } 70 71 72 /* posix_acl.c */ 73 74 extern void posix_acl_init(struct posix_acl *, int); 75 extern struct posix_acl *posix_acl_alloc(int, gfp_t); 76 extern struct posix_acl *posix_acl_clone(const struct posix_acl *, gfp_t); 77 extern int posix_acl_valid(const struct posix_acl *); 78 extern int posix_acl_permission(struct inode *, const struct posix_acl *, int); 79 extern struct posix_acl *posix_acl_from_mode(mode_t, gfp_t); 80 extern int posix_acl_equiv_mode(const struct posix_acl *, mode_t *); 81 extern int posix_acl_create_masq(struct posix_acl *, mode_t *); 82 extern int posix_acl_chmod_masq(struct posix_acl *, mode_t); 83 84 extern struct posix_acl *get_posix_acl(struct inode *, int); 85 extern int set_posix_acl(struct inode *, int, struct posix_acl *); 86 87 #ifdef CONFIG_FS_POSIX_ACL 88 static inline struct posix_acl *get_cached_acl(struct inode *inode, int type) 89 { 90 struct posix_acl **p, *acl; 91 switch (type) { 92 case ACL_TYPE_ACCESS: 93 p = &inode->i_acl; 94 break; 95 case ACL_TYPE_DEFAULT: 96 p = &inode->i_default_acl; 97 break; 98 default: 99 return ERR_PTR(-EINVAL); 100 } 101 acl = ACCESS_ONCE(*p); 102 if (acl) { 103 spin_lock(&inode->i_lock); 104 acl = *p; 105 if (acl != ACL_NOT_CACHED) 106 acl = posix_acl_dup(acl); 107 spin_unlock(&inode->i_lock); 108 } 109 return acl; 110 } 111 112 static inline int negative_cached_acl(struct inode *inode, int type) 113 { 114 struct posix_acl **p, *acl; 115 switch (type) { 116 case ACL_TYPE_ACCESS: 117 p = &inode->i_acl; 118 break; 119 case ACL_TYPE_DEFAULT: 120 p = &inode->i_default_acl; 121 break; 122 default: 123 BUG(); 124 } 125 acl = ACCESS_ONCE(*p); 126 if (acl) 127 return 0; 128 return 1; 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 *old = NULL; 136 spin_lock(&inode->i_lock); 137 switch (type) { 138 case ACL_TYPE_ACCESS: 139 old = inode->i_acl; 140 inode->i_acl = posix_acl_dup(acl); 141 break; 142 case ACL_TYPE_DEFAULT: 143 old = inode->i_default_acl; 144 inode->i_default_acl = posix_acl_dup(acl); 145 break; 146 } 147 spin_unlock(&inode->i_lock); 148 if (old != ACL_NOT_CACHED) 149 posix_acl_release(old); 150 } 151 152 static inline void forget_cached_acl(struct inode *inode, int type) 153 { 154 struct posix_acl *old = NULL; 155 spin_lock(&inode->i_lock); 156 switch (type) { 157 case ACL_TYPE_ACCESS: 158 old = inode->i_acl; 159 inode->i_acl = ACL_NOT_CACHED; 160 break; 161 case ACL_TYPE_DEFAULT: 162 old = inode->i_default_acl; 163 inode->i_default_acl = ACL_NOT_CACHED; 164 break; 165 } 166 spin_unlock(&inode->i_lock); 167 if (old != ACL_NOT_CACHED) 168 posix_acl_release(old); 169 } 170 171 static inline void forget_all_cached_acls(struct inode *inode) 172 { 173 struct posix_acl *old_access, *old_default; 174 spin_lock(&inode->i_lock); 175 old_access = inode->i_acl; 176 old_default = inode->i_default_acl; 177 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; 178 spin_unlock(&inode->i_lock); 179 if (old_access != ACL_NOT_CACHED) 180 posix_acl_release(old_access); 181 if (old_default != ACL_NOT_CACHED) 182 posix_acl_release(old_default); 183 } 184 #endif 185 186 static inline void cache_no_acl(struct inode *inode) 187 { 188 #ifdef CONFIG_FS_POSIX_ACL 189 inode->i_acl = NULL; 190 inode->i_default_acl = NULL; 191 #endif 192 } 193 194 #endif /* __LINUX_POSIX_ACL_H */ 195