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#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
  33struct ebitmap_node {
  34        struct ebitmap_node *next;
  35        unsigned long maps[EBITMAP_UNIT_NUMS];
  36        u32 startbit;
  37};
  38
  39struct 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
  46static 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
  59static inline void ebitmap_init(struct ebitmap *e)
  60{
  61        memset(e, 0, sizeof(*e));
  62}
  63
  64static 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
  87static 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
  99static 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
 109static 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
 124int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
 125int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
 126int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2, u32 last_e2bit);
 127int ebitmap_get_bit(struct ebitmap *e, unsigned long bit);
 128int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
 129void ebitmap_destroy(struct ebitmap *e);
 130int ebitmap_read(struct ebitmap *e, void *fp);
 131int ebitmap_write(struct ebitmap *e, void *fp);
 132
 133#ifdef CONFIG_NETLABEL
 134int ebitmap_netlbl_export(struct ebitmap *ebmap,
 135                          struct netlbl_lsm_catmap **catmap);
 136int ebitmap_netlbl_import(struct ebitmap *ebmap,
 137                          struct netlbl_lsm_catmap *catmap);
 138#else
 139static inline int ebitmap_netlbl_export(struct ebitmap *ebmap,
 140                                        struct netlbl_lsm_catmap **catmap)
 141{
 142        return -ENOMEM;
 143}
 144static 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_ */
 152