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
  34 struct ebitmap_node {
  35         struct ebitmap_node *next;
  36         unsigned long maps[EBITMAP_UNIT_NUMS];
  37         u32 startbit;
  38 };
  39
  40 struct 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
  47 static 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
  60 static inline void ebitmap_init(struct ebitmap *e)
  61 {
  62         memset(e, 0, sizeof(*e));
  63 }
  64
  65 static 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
  88 static 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
 100 static 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
 110 static 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
 125 int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
 126 int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
 127 int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2, u32 last_e2bit);
 128 int ebitmap_get_bit(struct ebitmap *e, unsigned long bit);
 129 int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
 130 void ebitmap_destroy(struct ebitmap *e);
 131 int ebitmap_read(struct ebitmap *e, void *fp);
 132 int ebitmap_write(struct ebitmap *e, void *fp);
 133
 134 void ebitmap_cache_init(void);
 135 void ebitmap_cache_destroy(void);
 136
 137 #ifdef CONFIG_NETLABEL
 138 int ebitmap_netlbl_export(struct ebitmap *ebmap,
 139                           struct netlbl_lsm_catmap **catmap);
 140 int ebitmap_netlbl_import(struct ebitmap *ebmap,
 141                           struct netlbl_lsm_catmap *catmap);
 142 #else
 143 static inline int ebitmap_netlbl_export(struct ebitmap *ebmap,
 144                                         struct netlbl_lsm_catmap **catmap)
 145 {
 146         return -ENOMEM;
 147 }
 148 static inline int ebitmap_netlbl_import(struct ebitmap *ebmap,
 149                                         struct netlbl_lsm_catmap *catmap)
 150 {
 151         return -ENOMEM;
 152 }
 153 #endif
 154
 155 #endif  /* _SS_EBITMAP_H_ */