security/selinux/ss/ebitmap.h

   1 /*
   2  * An extensible bitmap is a bitmap that supports an
   3  * arbitrary number of bits.  Extensible bitmaps are
   4  * used to represent sets of values, such as types,
   5  * roles, categories, and classes.
   6  *
   7  * Each extensible bitmap is implemented as a linked
   8  * list of bitmap nodes, where each bitmap node has
   9  * an explicitly specified starting bit position within
  10  * the total bitmap.
  11  *
  12  * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
  13  */
  14 #ifndef _SS_EBITMAP_H_
  15 #define _SS_EBITMAP_H_
  16
  17 #include <net/netlabel.h>
  18
  19 #define MAPTYPE u64                     /* portion of bitmap in each node */
  20 #define MAPSIZE (sizeof(MAPTYPE) * 8)   /* number of bits in node bitmap */
  21 #define MAPBIT  1ULL                    /* a bit in the node bitmap */
  22
  23 struct ebitmap_node {
  24         u32 startbit;           /* starting position in the total bitmap */
  25         MAPTYPE map;            /* this node's portion of the bitmap */
  26         struct ebitmap_node *next;
  27 };
  28
  29 struct ebitmap {
  30         struct ebitmap_node *node;      /* first node in the bitmap */
  31         u32 highbit;    /* highest position in the total bitmap */
  32 };
  33
  34 #define ebitmap_length(e) ((e)->highbit)
  35 #define ebitmap_startbit(e) ((e)->node ? (e)->node->startbit : 0)
  36
  37 static inline unsigned int ebitmap_start(struct ebitmap *e,
  38                                          struct ebitmap_node **n)
  39 {
  40         *n = e->node;
  41         return ebitmap_startbit(e);
  42 }
  43
  44 static inline void ebitmap_init(struct ebitmap *e)
  45 {
  46         memset(e, 0, sizeof(*e));
  47 }
  48
  49 static inline unsigned int ebitmap_next(struct ebitmap_node **n,
  50                                         unsigned int bit)
  51 {
  52         if ((bit == ((*n)->startbit + MAPSIZE - 1)) &&
  53             (*n)->next) {
  54                 *n = (*n)->next;
  55                 return (*n)->startbit;
  56         }
  57
  58         return (bit+1);
  59 }
  60
  61 static inline int ebitmap_node_get_bit(struct ebitmap_node * n,
  62                                        unsigned int bit)
  63 {
  64         if (n->map & (MAPBIT << (bit - n->startbit)))
  65                 return 1;
  66         return 0;
  67 }
  68
  69 #define ebitmap_for_each_bit(e, n, bit) \
  70         for (bit = ebitmap_start(e, &n); bit < ebitmap_length(e); bit = ebitmap_next(&n, bit)) \
  71
  72 int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
  73 int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
  74 int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2);
  75 int ebitmap_get_bit(struct ebitmap *e, unsigned long bit);
  76 int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
  77 void ebitmap_destroy(struct ebitmap *e);
  78 int ebitmap_read(struct ebitmap *e, void *fp);
  79
  80 #ifdef CONFIG_NETLABEL
  81 int ebitmap_netlbl_export(struct ebitmap *ebmap,
  82                           struct netlbl_lsm_secattr_catmap **catmap);
  83 int ebitmap_netlbl_import(struct ebitmap *ebmap,
  84                           struct netlbl_lsm_secattr_catmap *catmap);
  85 #else
  86 static inline int ebitmap_netlbl_export(struct ebitmap *ebmap,
  87                                 struct netlbl_lsm_secattr_catmap **catmap)
  88 {
  89         return -ENOMEM;
  90 }
  91 static inline int ebitmap_netlbl_import(struct ebitmap *ebmap,
  92                                 struct netlbl_lsm_secattr_catmap *catmap)
  93 {
  94         return -ENOMEM;
  95 }
  96 #endif
  97
  98 #endif  /* _SS_EBITMAP_H_ */