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
  40static 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
  53static inline void ebitmap_init(struct ebitmap *e)
  54{
  55        memset(e, 0, sizeof(*e));
  56}
  57
  58static 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
  81static 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
  93static 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
 103static 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
 118int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
 119int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
 120int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2);
 121int ebitmap_get_bit(struct ebitmap *e, unsigned long bit);
 122int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
 123void ebitmap_destroy(struct ebitmap *e);
 124int ebitmap_read(struct ebitmap *e, void *fp);
 125int ebitmap_write(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