1 #ifndef __LINUX_TEXTSEARCH_H
2 #define __LINUX_TEXTSEARCH_H
3
4 #include <linux/types.h>
5 #include <linux/list.h>
6 #include <linux/kernel.h>
7 #include <linux/err.h>
8 #include <linux/slab.h>
9
10 struct module;
11
12 struct ts_config;
13
14 #define TS_AUTOLOAD 1 /* Automatically load textsearch modules when needed */
15 #define TS_IGNORECASE 2 /* Searches string case insensitively */
16
17 /**
18 * struct ts_state - search state
19 * @offset: offset for next match
20 * @cb: control buffer, for persistent variables of get_next_block()
21 */
22 struct ts_state
23 {
24 unsigned int offset;
25 char cb[40];
26 };
27
28 /**
29 * struct ts_ops - search module operations
30 * @name: name of search algorithm
31 * @init: initialization function to prepare a search
32 * @find: find the next occurrence of the pattern
33 * @destroy: destroy algorithm specific parts of a search configuration
34 * @get_pattern: return head of pattern
35 * @get_pattern_len: return length of pattern
36 * @owner: module reference to algorithm
37 */
38 struct ts_ops
39 {
40 const char *name;
41 struct ts_config * (*init)(const void *, unsigned int, gfp_t, int);
42 unsigned int (*find)(struct ts_config *,
43 struct ts_state *);
44 void (*destroy)(struct ts_config *);
45 void * (*get_pattern)(struct ts_config *);
46 unsigned int (*get_pattern_len)(struct ts_config *);
47 struct module *owner;
48 struct list_head list;
49 };
50
51 /**
52 * struct ts_config - search configuration
53 * @ops: operations of chosen algorithm
54 * @flags: flags
55 * @get_next_block: callback to fetch the next block to search in
56 * @finish: callback to finalize a search
57 */
58 struct ts_config
59 {
60 struct ts_ops *ops;
61 int flags;
62
63 /**
64 * get_next_block - fetch next block of data
65 * @consumed: number of bytes consumed by the caller
66 * @dst: destination buffer
67 * @conf: search configuration
68 * @state: search state
69 *
70 * Called repeatedly until 0 is returned. Must assign the
71 * head of the next block of data to &*dst and return the length
72 * of the block or 0 if at the end. consumed == 0 indicates
73 * a new search. May store/read persistent values in state->cb.
74 */
75 unsigned int (*get_next_block)(unsigned int consumed,
76 const u8 **dst,
77 struct ts_config *conf,
78 struct ts_state *state);
79
80 /**
81 * finish - finalize/clean a series of get_next_block() calls
82 * @conf: search configuration
83 * @state: search state
84 *
85 * Called after the last use of get_next_block(), may be used
86 * to cleanup any leftovers.
87 */
88 void (*finish)(struct ts_config *conf,
89 struct ts_state *state);
90 };
91
92 /**
93 * textsearch_next - continue searching for a pattern
94 * @conf: search configuration
95 * @state: search state
96 *
97 * Continues a search looking for more occurrences of the pattern.
98 * textsearch_find() must be called to find the first occurrence
99 * in order to reset the state.
100 *
101 * Returns the position of the next occurrence of the pattern or
102 * UINT_MAX if not match was found.
103 */
textsearch_next(struct ts_config * conf,struct ts_state * state)104 static inline unsigned int textsearch_next(struct ts_config *conf,
105 struct ts_state *state)
106 {
107 unsigned int ret = conf->ops->find(conf, state);
108
109 if (conf->finish)
110 conf->finish(conf, state);
111
112 return ret;
113 }
114
115 /**
116 * textsearch_find - start searching for a pattern
117 * @conf: search configuration
118 * @state: search state
119 *
120 * Returns the position of first occurrence of the pattern or
121 * UINT_MAX if no match was found.
122 */
textsearch_find(struct ts_config * conf,struct ts_state * state)123 static inline unsigned int textsearch_find(struct ts_config *conf,
124 struct ts_state *state)
125 {
126 state->offset = 0;
127 return textsearch_next(conf, state);
128 }
129
130 /**
131 * textsearch_get_pattern - return head of the pattern
132 * @conf: search configuration
133 */
textsearch_get_pattern(struct ts_config * conf)134 static inline void *textsearch_get_pattern(struct ts_config *conf)
135 {
136 return conf->ops->get_pattern(conf);
137 }
138
139 /**
140 * textsearch_get_pattern_len - return length of the pattern
141 * @conf: search configuration
142 */
textsearch_get_pattern_len(struct ts_config * conf)143 static inline unsigned int textsearch_get_pattern_len(struct ts_config *conf)
144 {
145 return conf->ops->get_pattern_len(conf);
146 }
147
148 extern int textsearch_register(struct ts_ops *);
149 extern int textsearch_unregister(struct ts_ops *);
150 extern struct ts_config *textsearch_prepare(const char *, const void *,
151 unsigned int, gfp_t, int);
152 extern void textsearch_destroy(struct ts_config *conf);
153 extern unsigned int textsearch_find_continuous(struct ts_config *,
154 struct ts_state *,
155 const void *, unsigned int);
156
157
158 #define TS_PRIV_ALIGNTO 8
159 #define TS_PRIV_ALIGN(len) (((len) + TS_PRIV_ALIGNTO-1) & ~(TS_PRIV_ALIGNTO-1))
160
alloc_ts_config(size_t payload,gfp_t gfp_mask)161 static inline struct ts_config *alloc_ts_config(size_t payload,
162 gfp_t gfp_mask)
163 {
164 struct ts_config *conf;
165
166 conf = kzalloc(TS_PRIV_ALIGN(sizeof(*conf)) + payload, gfp_mask);
167 if (conf == NULL)
168 return ERR_PTR(-ENOMEM);
169
170 return conf;
171 }
172
ts_config_priv(struct ts_config * conf)173 static inline void *ts_config_priv(struct ts_config *conf)
174 {
175 return ((u8 *) conf + TS_PRIV_ALIGN(sizeof(struct ts_config)));
176 }
177
178 #endif
179