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
10struct module;
11
12struct 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 */
22struct 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 */
38struct 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 */
58struct 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 */
104static 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 */
123static 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 */
134static 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 */
143static inline unsigned int textsearch_get_pattern_len(struct ts_config *conf)
144{
145	return conf->ops->get_pattern_len(conf);
146}
147
148extern int textsearch_register(struct ts_ops *);
149extern int textsearch_unregister(struct ts_ops *);
150extern struct ts_config *textsearch_prepare(const char *, const void *,
151					    unsigned int, gfp_t, int);
152extern void textsearch_destroy(struct ts_config *conf);
153extern 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
161static 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
173static 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