LXR linux/include/linux/posix

   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
  34struct posix_acl_entry {
  35        short                   e_tag;
  36        unsigned short          e_perm;
  37        unsigned int            e_id;
  38};
  39
  40struct 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 */
  53static inline struct posix_acl *
  54posix_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 */
  64static inline void
  65posix_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
  74extern struct posix_acl *posix_acl_alloc(int, gfp_t);
  75extern struct posix_acl *posix_acl_clone(const struct posix_acl *, gfp_t);
  76extern int posix_acl_valid(const struct posix_acl *);
  77extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
  78extern struct posix_acl *posix_acl_from_mode(mode_t, gfp_t);
  79extern int posix_acl_equiv_mode(const struct posix_acl *, mode_t *);
  80extern int posix_acl_create_masq(struct posix_acl *, mode_t *);
  81extern int posix_acl_chmod_masq(struct posix_acl *, mode_t);
  82
  83extern struct posix_acl *get_posix_acl(struct inode *, int);
  84extern int set_posix_acl(struct inode *, int, struct posix_acl *);
  85
  86#ifdef CONFIG_FS_POSIX_ACL
  87static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
  88{
  89        struct posix_acl **p, *acl;
  90        switch (type) {
  91        case ACL_TYPE_ACCESS:
  92                p = &inode->i_acl;
  93                break;
  94        case ACL_TYPE_DEFAULT:
  95                p = &inode->i_default_acl;
  96                break;
  97        default:
  98                return ERR_PTR(-EINVAL);
  99        }
 100        acl = ACCESS_ONCE(*p);
 101        if (acl) {
 102                spin_lock(&inode->i_lock);
 103                acl = *p;
 104                if (acl != ACL_NOT_CACHED)
 105                        acl = posix_acl_dup(acl);
 106                spin_unlock(&inode->i_lock);
 107        }
 108        return acl;
 109}
 110
 111static inline void set_cached_acl(struct inode *inode,
 112                                  int type,
 113                                  struct posix_acl *acl)
 114{
 115        struct posix_acl *old = NULL;
 116        spin_lock(&inode->i_lock);
 117        switch (type) {
 118        case ACL_TYPE_ACCESS:
 119                old = inode->i_acl;
 120                inode->i_acl = posix_acl_dup(acl);
 121                break;
 122        case ACL_TYPE_DEFAULT:
 123                old = inode->i_default_acl;
 124                inode->i_default_acl = posix_acl_dup(acl);
 125                break;
 126        }
 127        spin_unlock(&inode->i_lock);
 128        if (old != ACL_NOT_CACHED)
 129                posix_acl_release(old);
 130}
 131
 132static inline void forget_cached_acl(struct inode *inode, int type)
 133{
 134        struct posix_acl *old = NULL;
 135        spin_lock(&inode->i_lock);
 136        switch (type) {
 137        case ACL_TYPE_ACCESS:
 138                old = inode->i_acl;
 139                inode->i_acl = ACL_NOT_CACHED;
 140                break;
 141        case ACL_TYPE_DEFAULT:
 142                old = inode->i_default_acl;
 143                inode->i_default_acl = ACL_NOT_CACHED;
 144                break;
 145        }
 146        spin_unlock(&inode->i_lock);
 147        if (old != ACL_NOT_CACHED)
 148                posix_acl_release(old);
 149}
 150#endif
 151
 152static inline void cache_no_acl(struct inode *inode)
 153{
 154#ifdef CONFIG_FS_POSIX_ACL
 155        inode->i_acl = NULL;
 156        inode->i_default_acl = NULL;
 157#endif
 158}
 159
 160#endif  /* __LINUX_POSIX_ACL_H */
 161