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 unsigned int e_id; 40 }; 41 42 struct posix_acl { 43 union { 44 atomic_t a_refcount; 45 struct rcu_head a_rcu; 46 }; 47 unsigned int a_count; 48 struct posix_acl_entry a_entries[0]; 49 }; 50 51 #define FOREACH_ACL_ENTRY(pa, acl, pe) \ 52 for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++) 53 54 55 /* 56 * Duplicate an ACL handle. 57 */ 58 static inline struct posix_acl * 59 posix_acl_dup(struct posix_acl *acl) 60 { 61 if (acl) 62 atomic_inc(&acl->a_refcount); 63 return acl; 64 } 65 66 /* 67 * Free an ACL handle. 68 */ 69 static inline void 70 posix_acl_release(struct posix_acl *acl) 71 { 72 if (acl && atomic_dec_and_test(&acl->a_refcount)) 73 kfree_rcu(acl, a_rcu); 74 } 75 76 77 /* posix_acl.c */ 78 79 extern void posix_acl_init(struct posix_acl *, int); 80 extern struct posix_acl *posix_acl_alloc(int, gfp_t); 81 extern int posix_acl_valid(const struct posix_acl *); 82 extern int posix_acl_permission(struct inode *, const struct posix_acl *, int); 83 extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t); 84 extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *); 85 extern int posix_acl_create(struct posix_acl **, gfp_t, umode_t *); 86 extern int posix_acl_chmod(struct posix_acl **, gfp_t, umode_t); 87 88 extern struct posix_acl *get_posix_acl(struct inode *, int); 89 extern int set_posix_acl(struct inode *, int, struct posix_acl *); 90 91 #ifdef CONFIG_FS_POSIX_ACL 92 static inline struct posix_acl **acl_by_type(struct inode *inode, int type) 93 { 94 switch (type) { 95 case ACL_TYPE_ACCESS: 96 return &inode->i_acl; 97 case ACL_TYPE_DEFAULT: 98 return &inode->i_default_acl; 99 default: 100 BUG(); 101 } 102 } 103 104 static inline struct posix_acl *get_cached_acl(struct inode *inode, int type) 105 { 106 struct posix_acl **p = acl_by_type(inode, type); 107 struct posix_acl *acl = ACCESS_ONCE(*p); 108 if (acl) { 109 spin_lock(&inode->i_lock); 110 acl = *p; 111 if (acl != ACL_NOT_CACHED) 112 acl = posix_acl_dup(acl); 113 spin_unlock(&inode->i_lock); 114 } 115 return acl; 116 } 117 118 static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) 119 { 120 return rcu_dereference(*acl_by_type(inode, type)); 121 } 122 123 static inline void set_cached_acl(struct inode *inode, 124 int type, 125 struct posix_acl *acl) 126 { 127 struct posix_acl **p = acl_by_type(inode, type); 128 struct posix_acl *old; 129 spin_lock(&inode->i_lock); 130 old = *p; 131 rcu_assign_pointer(*p, posix_acl_dup(acl)); 132 spin_unlock(&inode->i_lock); 133 if (old != ACL_NOT_CACHED) 134 posix_acl_release(old); 135 } 136 137 static inline void forget_cached_acl(struct inode *inode, int type) 138 { 139 struct posix_acl **p = acl_by_type(inode, type); 140 struct posix_acl *old; 141 spin_lock(&inode->i_lock); 142 old = *p; 143 *p = ACL_NOT_CACHED; 144 spin_unlock(&inode->i_lock); 145 if (old != ACL_NOT_CACHED) 146 posix_acl_release(old); 147 } 148 149 static inline void forget_all_cached_acls(struct inode *inode) 150 { 151 struct posix_acl *old_access, *old_default; 152 spin_lock(&inode->i_lock); 153 old_access = inode->i_acl; 154 old_default = inode->i_default_acl; 155 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; 156 spin_unlock(&inode->i_lock); 157 if (old_access != ACL_NOT_CACHED) 158 posix_acl_release(old_access); 159 if (old_default != ACL_NOT_CACHED) 160 posix_acl_release(old_default); 161 } 162 #endif 163 164 static inline void cache_no_acl(struct inode *inode) 165 { 166 #ifdef CONFIG_FS_POSIX_ACL 167 inode->i_acl = NULL; 168 inode->i_default_acl = NULL; 169 #endif 170 } 171 172 #endif /* __LINUX_POSIX_ACL_H */ 173