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