1 /* 2 File: linux/posix_acl.h 3 4 (C) 2002 Andreas Gruenbacher, <[email protected]> 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 35 struct posix_acl_entry { 36 short e_tag; 37 unsigned short e_perm; 38 unsigned int e_id; 39 }; 40 41 struct 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 */ 57 static inline struct posix_acl * 58 posix_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 */ 68 static inline void 69 posix_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 78 extern void posix_acl_init(struct posix_acl *, int); 79 extern struct posix_acl *posix_acl_alloc(int, gfp_t); 80 extern int posix_acl_valid(const struct posix_acl *); 81 extern int posix_acl_permission(struct inode *, const struct posix_acl *, int); 82 extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t); 83 extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *); 84 extern int posix_acl_create(struct posix_acl **, gfp_t, umode_t *); 85 extern int posix_acl_chmod(struct posix_acl **, gfp_t, umode_t); 86 87 extern struct posix_acl *get_posix_acl(struct inode *, int); 88 extern int set_posix_acl(struct inode *, int, struct posix_acl *); 89 90 #ifdef CONFIG_FS_POSIX_ACL 91 static 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 } 102 103 static 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 } 116 117 static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) 118 { 119 return rcu_dereference(*acl_by_type(inode, type)); 120 } 121 122 static 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 } 135 136 static 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 } 147 148 static 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 162 163 static 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 */ 172