| 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_update_mode(struct inode *, umode_t *, struct posix_acl **); |
| 93 | extern int posix_acl_chmod(struct posix_acl **, gfp_t, umode_t); |
| 94 | |
| 95 | extern struct posix_acl *get_posix_acl(struct inode *, int); |
| 96 | extern int set_posix_acl(struct inode *, int, struct posix_acl *); |
| 97 | |
| 98 | #ifdef CONFIG_FS_POSIX_ACL |
| 99 | static inline struct posix_acl **acl_by_type(struct inode *inode, int type) |
| 100 | { |
| 101 | switch (type) { |
| 102 | case ACL_TYPE_ACCESS: |
| 103 | return &inode->i_acl; |
| 104 | case ACL_TYPE_DEFAULT: |
| 105 | return &inode->i_default_acl; |
| 106 | default: |
| 107 | BUG(); |
| 108 | } |
| 109 | } |
| 110 | |
| 111 | static inline struct posix_acl *get_cached_acl(struct inode *inode, int type) |
| 112 | { |
| 113 | struct posix_acl **p = acl_by_type(inode, type); |
| 114 | struct posix_acl *acl = ACCESS_ONCE(*p); |
| 115 | if (acl) { |
| 116 | spin_lock(&inode->i_lock); |
| 117 | acl = *p; |
| 118 | if (acl != ACL_NOT_CACHED) |
| 119 | acl = posix_acl_dup(acl); |
| 120 | spin_unlock(&inode->i_lock); |
| 121 | } |
| 122 | return acl; |
| 123 | } |
| 124 | |
| 125 | static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) |
| 126 | { |
| 127 | return rcu_dereference(*acl_by_type(inode, type)); |
| 128 | } |
| 129 | |
| 130 | static inline void set_cached_acl(struct inode *inode, |
| 131 | int type, |
| 132 | struct posix_acl *acl) |
| 133 | { |
| 134 | struct posix_acl **p = acl_by_type(inode, type); |
| 135 | struct posix_acl *old; |
| 136 | spin_lock(&inode->i_lock); |
| 137 | old = *p; |
| 138 | rcu_assign_pointer(*p, posix_acl_dup(acl)); |
| 139 | spin_unlock(&inode->i_lock); |
| 140 | if (old != ACL_NOT_CACHED) |
| 141 | posix_acl_release(old); |
| 142 | } |
| 143 | |
| 144 | static inline void forget_cached_acl(struct inode *inode, int type) |
| 145 | { |
| 146 | struct posix_acl **p = acl_by_type(inode, type); |
| 147 | struct posix_acl *old; |
| 148 | spin_lock(&inode->i_lock); |
| 149 | old = *p; |
| 150 | *p = ACL_NOT_CACHED; |
| 151 | spin_unlock(&inode->i_lock); |
| 152 | if (old != ACL_NOT_CACHED) |
| 153 | posix_acl_release(old); |
| 154 | } |
| 155 | |
| 156 | static inline void forget_all_cached_acls(struct inode *inode) |
| 157 | { |
| 158 | struct posix_acl *old_access, *old_default; |
| 159 | spin_lock(&inode->i_lock); |
| 160 | old_access = inode->i_acl; |
| 161 | old_default = inode->i_default_acl; |
| 162 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; |
| 163 | spin_unlock(&inode->i_lock); |
| 164 | if (old_access != ACL_NOT_CACHED) |
| 165 | posix_acl_release(old_access); |
| 166 | if (old_default != ACL_NOT_CACHED) |
| 167 | posix_acl_release(old_default); |
| 168 | } |
| 169 | #endif |
| 170 | |
| 171 | static inline void cache_no_acl(struct inode *inode) |
| 172 | { |
| 173 | #ifdef CONFIG_FS_POSIX_ACL |
| 174 | inode->i_acl = NULL; |
| 175 | inode->i_default_acl = NULL; |
| 176 | #endif |
| 177 | } |
| 178 | |
| 179 | #endif /* __LINUX_POSIX_ACL_H */ |