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