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