1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef __LINUX_TEXTSEARCH_H |
3 | #define __LINUX_TEXTSEARCH_H |
4 | |
5 | #include <linux/types.h> |
6 | #include <linux/list.h> |
7 | #include <linux/kernel.h> |
8 | #include <linux/err.h> |
9 | #include <linux/slab.h> |
10 | |
11 | struct module; |
12 | |
13 | struct ts_config; |
14 | |
15 | #define TS_AUTOLOAD 1 /* Automatically load textsearch modules when needed */ |
16 | #define TS_IGNORECASE 2 /* Searches string case insensitively */ |
17 | |
18 | /** |
19 | * struct ts_state - search state |
20 | * @offset: offset for next match |
21 | * @cb: control buffer, for persistent variables of get_next_block() |
22 | */ |
23 | struct ts_state |
24 | { |
25 | unsigned int offset; |
26 | char cb[48]; |
27 | }; |
28 | |
29 | /** |
30 | * struct ts_ops - search module operations |
31 | * @name: name of search algorithm |
32 | * @init: initialization function to prepare a search |
33 | * @find: find the next occurrence of the pattern |
34 | * @destroy: destroy algorithm specific parts of a search configuration |
35 | * @get_pattern: return head of pattern |
36 | * @get_pattern_len: return length of pattern |
37 | * @owner: module reference to algorithm |
38 | */ |
39 | struct ts_ops |
40 | { |
41 | const char *name; |
42 | struct ts_config * (*init)(const void *, unsigned int, gfp_t, int); |
43 | unsigned int (*find)(struct ts_config *, |
44 | struct ts_state *); |
45 | void (*destroy)(struct ts_config *); |
46 | void * (*get_pattern)(struct ts_config *); |
47 | unsigned int (*get_pattern_len)(struct ts_config *); |
48 | struct module *owner; |
49 | struct list_head list; |
50 | }; |
51 | |
52 | /** |
53 | * struct ts_config - search configuration |
54 | * @ops: operations of chosen algorithm |
55 | * @flags: flags |
56 | * @get_next_block: callback to fetch the next block to search in |
57 | * @finish: callback to finalize a search |
58 | */ |
59 | struct ts_config |
60 | { |
61 | struct ts_ops *ops; |
62 | int flags; |
63 | |
64 | /** |
65 | * @get_next_block: fetch next block of data |
66 | * @consumed: number of bytes consumed by the caller |
67 | * @dst: destination buffer |
68 | * @conf: search configuration |
69 | * @state: search state |
70 | * |
71 | * Called repeatedly until 0 is returned. Must assign the |
72 | * head of the next block of data to &*dst and return the length |
73 | * of the block or 0 if at the end. consumed == 0 indicates |
74 | * a new search. May store/read persistent values in state->cb. |
75 | */ |
76 | unsigned int (*get_next_block)(unsigned int consumed, |
77 | const u8 **dst, |
78 | struct ts_config *conf, |
79 | struct ts_state *state); |
80 | |
81 | /** |
82 | * @finish: finalize/clean a series of get_next_block() calls |
83 | * @conf: search configuration |
84 | * @state: search state |
85 | * |
86 | * Called after the last use of get_next_block(), may be used |
87 | * to cleanup any leftovers. |
88 | */ |
89 | void (*finish)(struct ts_config *conf, |
90 | struct ts_state *state); |
91 | }; |
92 | |
93 | /** |
94 | * textsearch_next - continue searching for a pattern |
95 | * @conf: search configuration |
96 | * @state: search state |
97 | * |
98 | * Continues a search looking for more occurrences of the pattern. |
99 | * textsearch_find() must be called to find the first occurrence |
100 | * in order to reset the state. |
101 | * |
102 | * Returns the position of the next occurrence of the pattern or |
103 | * UINT_MAX if not match was found. |
104 | */ |
105 | static inline unsigned int textsearch_next(struct ts_config *conf, |
106 | struct ts_state *state) |
107 | { |
108 | unsigned int ret = conf->ops->find(conf, state); |
109 | |
110 | if (conf->finish) |
111 | conf->finish(conf, state); |
112 | |
113 | return ret; |
114 | } |
115 | |
116 | /** |
117 | * textsearch_find - start searching for a pattern |
118 | * @conf: search configuration |
119 | * @state: search state |
120 | * |
121 | * Returns the position of first occurrence of the pattern or |
122 | * UINT_MAX if no match was found. |
123 | */ |
124 | static inline unsigned int textsearch_find(struct ts_config *conf, |
125 | struct ts_state *state) |
126 | { |
127 | state->offset = 0; |
128 | return textsearch_next(conf, state); |
129 | } |
130 | |
131 | /** |
132 | * textsearch_get_pattern - return head of the pattern |
133 | * @conf: search configuration |
134 | */ |
135 | static inline void *textsearch_get_pattern(struct ts_config *conf) |
136 | { |
137 | return conf->ops->get_pattern(conf); |
138 | } |
139 | |
140 | /** |
141 | * textsearch_get_pattern_len - return length of the pattern |
142 | * @conf: search configuration |
143 | */ |
144 | static inline unsigned int textsearch_get_pattern_len(struct ts_config *conf) |
145 | { |
146 | return conf->ops->get_pattern_len(conf); |
147 | } |
148 | |
149 | extern int textsearch_register(struct ts_ops *); |
150 | extern int textsearch_unregister(struct ts_ops *); |
151 | extern struct ts_config *textsearch_prepare(const char *, const void *, |
152 | unsigned int, gfp_t, int); |
153 | extern void textsearch_destroy(struct ts_config *conf); |
154 | extern unsigned int textsearch_find_continuous(struct ts_config *, |
155 | struct ts_state *, |
156 | const void *, unsigned int); |
157 | |
158 | |
159 | #define TS_PRIV_ALIGNTO 8 |
160 | #define TS_PRIV_ALIGN(len) (((len) + TS_PRIV_ALIGNTO-1) & ~(TS_PRIV_ALIGNTO-1)) |
161 | |
162 | static inline struct ts_config *alloc_ts_config(size_t payload, |
163 | gfp_t gfp_mask) |
164 | { |
165 | struct ts_config *conf; |
166 | |
167 | conf = kzalloc(TS_PRIV_ALIGN(sizeof(*conf)) + payload, flags: gfp_mask); |
168 | if (conf == NULL) |
169 | return ERR_PTR(error: -ENOMEM); |
170 | |
171 | return conf; |
172 | } |
173 | |
174 | static inline void *ts_config_priv(struct ts_config *conf) |
175 | { |
176 | return ((u8 *) conf + TS_PRIV_ALIGN(sizeof(struct ts_config))); |
177 | } |
178 | |
179 | #endif |
180 | |