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