LXR linux/security/selinux/ss/ebitmap.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * An extensible bitmap is a bitmap that supports an
   4 * arbitrary number of bits.  Extensible bitmaps are
   5 * used to represent sets of values, such as types,
   6 * roles, categories, and classes.
   7 *
   8 * Each extensible bitmap is implemented as a linked
   9 * list of bitmap nodes, where each bitmap node has
  10 * an explicitly specified starting bit position within
  11 * the total bitmap.
  12 *
  13 * Author : Stephen Smalley, <sds@tycho.nsa.gov>
  14 */
  15#ifndef _SS_EBITMAP_H_
  16#define _SS_EBITMAP_H_
  17
  18#include <net/netlabel.h>
  19
  20#ifdef CONFIG_64BIT
  21#define EBITMAP_NODE_SIZE       64
  22#else
  23#define EBITMAP_NODE_SIZE       32
  24#endif
  25
  26#define EBITMAP_UNIT_NUMS       ((EBITMAP_NODE_SIZE-sizeof(void *)-sizeof(u32))\
  27                                        / sizeof(unsigned long))
  28#define EBITMAP_UNIT_SIZE       BITS_PER_LONG
  29#define EBITMAP_SIZE            (EBITMAP_UNIT_NUMS * EBITMAP_UNIT_SIZE)
  30#define EBITMAP_BIT             1ULL
  31#define EBITMAP_SHIFT_UNIT_SIZE(x)                                      \
  32        (((x) >> EBITMAP_UNIT_SIZE / 2) >> EBITMAP_UNIT_SIZE / 2)
  33
  34struct ebitmap_node {
  35        struct ebitmap_node *next;
  36        unsigned long maps[EBITMAP_UNIT_NUMS];
  37        u32 startbit;
  38};
  39
  40struct ebitmap {
  41        struct ebitmap_node *node;      /* first node in the bitmap */
  42        u32 highbit;    /* highest position in the total bitmap */
  43};
  44
  45#define ebitmap_length(e) ((e)->highbit)
  46
  47static inline unsigned int ebitmap_start_positive(struct ebitmap *e,
  48                                                  struct ebitmap_node **n)
  49{
  50        unsigned int ofs;
  51
  52        for (*n = e->node; *n; *n = (*n)->next) {
  53                ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
  54                if (ofs < EBITMAP_SIZE)
  55                        return (*n)->startbit + ofs;
  56        }
  57        return ebitmap_length(e);
  58}
  59
  60static inline void ebitmap_init(struct ebitmap *e)
  61{
  62        memset(e, 0, sizeof(*e));
  63}
  64
  65static inline unsigned int ebitmap_next_positive(struct ebitmap *e,
  66                                                 struct ebitmap_node **n,
  67                                                 unsigned int bit)
  68{
  69        unsigned int ofs;
  70
  71        ofs = find_next_bit((*n)->maps, EBITMAP_SIZE, bit - (*n)->startbit + 1);
  72        if (ofs < EBITMAP_SIZE)
  73                return ofs + (*n)->startbit;
  74
  75        for (*n = (*n)->next; *n; *n = (*n)->next) {
  76                ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
  77                if (ofs < EBITMAP_SIZE)
  78                        return ofs + (*n)->startbit;
  79        }
  80        return ebitmap_length(e);
  81}
  82
  83#define EBITMAP_NODE_INDEX(node, bit)   \
  84        (((bit) - (node)->startbit) / EBITMAP_UNIT_SIZE)
  85#define EBITMAP_NODE_OFFSET(node, bit)  \
  86        (((bit) - (node)->startbit) % EBITMAP_UNIT_SIZE)
  87
  88static inline int ebitmap_node_get_bit(struct ebitmap_node *n,
  89                                       unsigned int bit)
  90{
  91        unsigned int index = EBITMAP_NODE_INDEX(n, bit);
  92        unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
  93
  94        BUG_ON(index >= EBITMAP_UNIT_NUMS);
  95        if ((n->maps[index] & (EBITMAP_BIT << ofs)))
  96                return 1;
  97        return 0;
  98}
  99
 100static inline void ebitmap_node_set_bit(struct ebitmap_node *n,
 101                                        unsigned int bit)
 102{
 103        unsigned int index = EBITMAP_NODE_INDEX(n, bit);
 104        unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
 105
 106        BUG_ON(index >= EBITMAP_UNIT_NUMS);
 107        n->maps[index] |= (EBITMAP_BIT << ofs);
 108}
 109
 110static inline void ebitmap_node_clr_bit(struct ebitmap_node *n,
 111                                        unsigned int bit)
 112{
 113        unsigned int index = EBITMAP_NODE_INDEX(n, bit);
 114        unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
 115
 116        BUG_ON(index >= EBITMAP_UNIT_NUMS);
 117        n->maps[index] &= ~(EBITMAP_BIT << ofs);
 118}
 119
 120#define ebitmap_for_each_positive_bit(e, n, bit)        \
 121        for (bit = ebitmap_start_positive(e, &n);       \
 122             bit < ebitmap_length(e);                   \
 123             bit = ebitmap_next_positive(e, &n, bit))   \
 124
 125int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
 126int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
 127int ebitmap_and(struct ebitmap *dst, struct ebitmap *e1, struct ebitmap *e2);
 128int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2, u32 last_e2bit);
 129int ebitmap_get_bit(struct ebitmap *e, unsigned long bit);
 130int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
 131void ebitmap_destroy(struct ebitmap *e);
 132int ebitmap_read(struct ebitmap *e, void *fp);
 133int ebitmap_write(struct ebitmap *e, void *fp);
 134u32 ebitmap_hash(const struct ebitmap *e, u32 hash);
 135
 136#ifdef CONFIG_NETLABEL
 137int ebitmap_netlbl_export(struct ebitmap *ebmap,
 138                          struct netlbl_lsm_catmap **catmap);
 139int ebitmap_netlbl_import(struct ebitmap *ebmap,
 140                          struct netlbl_lsm_catmap *catmap);
 141#else
 142static inline int ebitmap_netlbl_export(struct ebitmap *ebmap,
 143                                        struct netlbl_lsm_catmap **catmap)
 144{
 145        return -ENOMEM;
 146}
 147static inline int ebitmap_netlbl_import(struct ebitmap *ebmap,
 148                                        struct netlbl_lsm_catmap *catmap)
 149{
 150        return -ENOMEM;
 151}
 152#endif
 153
 154#endif  /* _SS_EBITMAP_H_ */
 155