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 #ifdef CONFIG_64BIT
  20 #define EBITMAP_NODE_SIZE       64
  21 #else
  22 #define EBITMAP_NODE_SIZE       32
  23 #endif
  24
  25 #define EBITMAP_UNIT_NUMS       ((EBITMAP_NODE_SIZE-sizeof(void *)-sizeof(u32))\
  26                                         / sizeof(unsigned long))
  27 #define EBITMAP_UNIT_SIZE       BITS_PER_LONG
  28 #define EBITMAP_SIZE            (EBITMAP_UNIT_NUMS * EBITMAP_UNIT_SIZE)
  29 #define EBITMAP_BIT             1ULL
  30 #define EBITMAP_SHIFT_UNIT_SIZE(x)                                      \
  31         (((x) >> EBITMAP_UNIT_SIZE / 2) >> EBITMAP_UNIT_SIZE / 2)
  32
  33 struct ebitmap_node {
  34         struct ebitmap_node *next;
  35         unsigned long maps[EBITMAP_UNIT_NUMS];
  36         u32 startbit;
  37 };
  38
  39 struct ebitmap {
  40         struct ebitmap_node *node;      /* first node in the bitmap */
  41         u32 highbit;    /* highest position in the total bitmap */
  42 };
  43
  44 #define ebitmap_length(e) ((e)->highbit)
  45
  46 static inline unsigned int ebitmap_start_positive(struct ebitmap *e,
  47                                                   struct ebitmap_node **n)
  48 {
  49         unsigned int ofs;
  50
  51         for (*n = e->node; *n; *n = (*n)->next) {
  52                 ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
  53                 if (ofs < EBITMAP_SIZE)
  54                         return (*n)->startbit + ofs;
  55         }
  56         return ebitmap_length(e);
  57 }
  58
  59 static inline void ebitmap_init(struct ebitmap *e)
  60 {
  61         memset(e, 0, sizeof(*e));
  62 }
  63
  64 static inline unsigned int ebitmap_next_positive(struct ebitmap *e,
  65                                                  struct ebitmap_node **n,
  66                                                  unsigned int bit)
  67 {
  68         unsigned int ofs;
  69
  70         ofs = find_next_bit((*n)->maps, EBITMAP_SIZE, bit - (*n)->startbit + 1);
  71         if (ofs < EBITMAP_SIZE)
  72                 return ofs + (*n)->startbit;
  73
  74         for (*n = (*n)->next; *n; *n = (*n)->next) {
  75                 ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
  76                 if (ofs < EBITMAP_SIZE)
  77                         return ofs + (*n)->startbit;
  78         }
  79         return ebitmap_length(e);
  80 }
  81
  82 #define EBITMAP_NODE_INDEX(node, bit)   \
  83         (((bit) - (node)->startbit) / EBITMAP_UNIT_SIZE)
  84 #define EBITMAP_NODE_OFFSET(node, bit)  \
  85         (((bit) - (node)->startbit) % EBITMAP_UNIT_SIZE)
  86
  87 static inline int ebitmap_node_get_bit(struct ebitmap_node *n,
  88                                        unsigned int bit)
  89 {
  90         unsigned int index = EBITMAP_NODE_INDEX(n, bit);
  91         unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
  92
  93         BUG_ON(index >= EBITMAP_UNIT_NUMS);
  94         if ((n->maps[index] & (EBITMAP_BIT << ofs)))
  95                 return 1;
  96         return 0;
  97 }
  98
  99 static inline void ebitmap_node_set_bit(struct ebitmap_node *n,
 100                                         unsigned int bit)
 101 {
 102         unsigned int index = EBITMAP_NODE_INDEX(n, bit);
 103         unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
 104
 105         BUG_ON(index >= EBITMAP_UNIT_NUMS);
 106         n->maps[index] |= (EBITMAP_BIT << ofs);
 107 }
 108
 109 static inline void ebitmap_node_clr_bit(struct ebitmap_node *n,
 110                                         unsigned int bit)
 111 {
 112         unsigned int index = EBITMAP_NODE_INDEX(n, bit);
 113         unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
 114
 115         BUG_ON(index >= EBITMAP_UNIT_NUMS);
 116         n->maps[index] &= ~(EBITMAP_BIT << ofs);
 117 }
 118
 119 #define ebitmap_for_each_positive_bit(e, n, bit)        \
 120         for (bit = ebitmap_start_positive(e, &n);       \
 121              bit < ebitmap_length(e);                   \
 122              bit = ebitmap_next_positive(e, &n, bit))   \
 123
 124 int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
 125 int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
 126 int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2, u32 last_e2bit);
 127 int ebitmap_get_bit(struct ebitmap *e, unsigned long bit);
 128 int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
 129 void ebitmap_destroy(struct ebitmap *e);
 130 int ebitmap_read(struct ebitmap *e, void *fp);
 131 int ebitmap_write(struct ebitmap *e, void *fp);
 132
 133 #ifdef CONFIG_NETLABEL
 134 int ebitmap_netlbl_export(struct ebitmap *ebmap,
 135                           struct netlbl_lsm_catmap **catmap);
 136 int ebitmap_netlbl_import(struct ebitmap *ebmap,
 137                           struct netlbl_lsm_catmap *catmap);
 138 #else
 139 static inline int ebitmap_netlbl_export(struct ebitmap *ebmap,
 140                                         struct netlbl_lsm_catmap **catmap)
 141 {
 142         return -ENOMEM;
 143 }
 144 static inline int ebitmap_netlbl_import(struct ebitmap *ebmap,
 145                                         struct netlbl_lsm_catmap *catmap)
 146 {
 147         return -ENOMEM;
 148 }
 149 #endif
 150
 151 #endif  /* _SS_EBITMAP_H_ */