LXR linux/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
  27struct ebitmap_node {
  28        struct ebitmap_node *next;
  29        unsigned long maps[EBITMAP_UNIT_NUMS];
  30        u32 startbit;
  31};
  32
  33struct 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
  41static 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
  54static inline void ebitmap_init(struct ebitmap *e)
  55{
  56        memset(e, 0, sizeof(*e));
  57}
  58
  59static 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
  82static 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
  94static 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
 104static 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
 119int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
 120int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
 121int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2);
 122int ebitmap_get_bit(struct ebitmap *e, unsigned long bit);
 123int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
 124void ebitmap_destroy(struct ebitmap *e);
 125int ebitmap_read(struct ebitmap *e, void *fp);
 126
 127#ifdef CONFIG_NETLABEL
 128int ebitmap_netlbl_export(struct ebitmap *ebmap,
 129                          struct netlbl_lsm_secattr_catmap **catmap);
 130int ebitmap_netlbl_import(struct ebitmap *ebmap,
 131                          struct netlbl_lsm_secattr_catmap *catmap);
 132#else
 133static inline int ebitmap_netlbl_export(struct ebitmap *ebmap,
 134                                struct netlbl_lsm_secattr_catmap **catmap)
 135{
 136        return -ENOMEM;
 137}
 138static 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_ */
 146