1 |
62 |
marcus.erl |
/*
|
2 |
|
|
* lib/ts_fsm.c A naive finite state machine text search approach
|
3 |
|
|
*
|
4 |
|
|
* This program is free software; you can redistribute it and/or
|
5 |
|
|
* modify it under the terms of the GNU General Public License
|
6 |
|
|
* as published by the Free Software Foundation; either version
|
7 |
|
|
* 2 of the License, or (at your option) any later version.
|
8 |
|
|
*
|
9 |
|
|
* Authors: Thomas Graf <tgraf@suug.ch>
|
10 |
|
|
*
|
11 |
|
|
* ==========================================================================
|
12 |
|
|
*
|
13 |
|
|
* A finite state machine consists of n states (struct ts_fsm_token)
|
14 |
|
|
* representing the pattern as a finite automation. The data is read
|
15 |
|
|
* sequentially on an octet basis. Every state token specifies the number
|
16 |
|
|
* of recurrences and the type of value accepted which can be either a
|
17 |
|
|
* specific character or ctype based set of characters. The available
|
18 |
|
|
* type of recurrences include 1, (0|1), [0 n], and [1 n].
|
19 |
|
|
*
|
20 |
|
|
* The algorithm differs between strict/non-strict mode specifying
|
21 |
|
|
* whether the pattern has to start at the first octet. Strict mode
|
22 |
|
|
* is enabled by default and can be disabled by inserting
|
23 |
|
|
* TS_FSM_HEAD_IGNORE as the first token in the chain.
|
24 |
|
|
*
|
25 |
|
|
* The runtime performance of the algorithm should be around O(n),
|
26 |
|
|
* however while in strict mode the average runtime can be better.
|
27 |
|
|
*/
|
28 |
|
|
|
29 |
|
|
#include <linux/module.h>
|
30 |
|
|
#include <linux/types.h>
|
31 |
|
|
#include <linux/string.h>
|
32 |
|
|
#include <linux/ctype.h>
|
33 |
|
|
#include <linux/textsearch.h>
|
34 |
|
|
#include <linux/textsearch_fsm.h>
|
35 |
|
|
|
36 |
|
|
struct ts_fsm
|
37 |
|
|
{
|
38 |
|
|
unsigned int ntokens;
|
39 |
|
|
struct ts_fsm_token tokens[0];
|
40 |
|
|
};
|
41 |
|
|
|
42 |
|
|
/* other values derived from ctype.h */
|
43 |
|
|
#define _A 0x100 /* ascii */
|
44 |
|
|
#define _W 0x200 /* wildcard */
|
45 |
|
|
|
46 |
|
|
/* Map to _ctype flags and some magic numbers */
|
47 |
|
|
static const u16 token_map[TS_FSM_TYPE_MAX+1] = {
|
48 |
|
|
[TS_FSM_SPECIFIC] = 0,
|
49 |
|
|
[TS_FSM_WILDCARD] = _W,
|
50 |
|
|
[TS_FSM_CNTRL] = _C,
|
51 |
|
|
[TS_FSM_LOWER] = _L,
|
52 |
|
|
[TS_FSM_UPPER] = _U,
|
53 |
|
|
[TS_FSM_PUNCT] = _P,
|
54 |
|
|
[TS_FSM_SPACE] = _S,
|
55 |
|
|
[TS_FSM_DIGIT] = _D,
|
56 |
|
|
[TS_FSM_XDIGIT] = _D | _X,
|
57 |
|
|
[TS_FSM_ALPHA] = _U | _L,
|
58 |
|
|
[TS_FSM_ALNUM] = _U | _L | _D,
|
59 |
|
|
[TS_FSM_PRINT] = _P | _U | _L | _D | _SP,
|
60 |
|
|
[TS_FSM_GRAPH] = _P | _U | _L | _D,
|
61 |
|
|
[TS_FSM_ASCII] = _A,
|
62 |
|
|
};
|
63 |
|
|
|
64 |
|
|
static const u16 token_lookup_tbl[256] = {
|
65 |
|
|
_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 0- 3 */
|
66 |
|
|
_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 4- 7 */
|
67 |
|
|
_W|_A|_C, _W|_A|_C|_S, _W|_A|_C|_S, _W|_A|_C|_S, /* 8- 11 */
|
68 |
|
|
_W|_A|_C|_S, _W|_A|_C|_S, _W|_A|_C, _W|_A|_C, /* 12- 15 */
|
69 |
|
|
_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 16- 19 */
|
70 |
|
|
_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 20- 23 */
|
71 |
|
|
_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 24- 27 */
|
72 |
|
|
_W|_A|_C, _W|_A|_C, _W|_A|_C, _W|_A|_C, /* 28- 31 */
|
73 |
|
|
_W|_A|_S|_SP, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 32- 35 */
|
74 |
|
|
_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 36- 39 */
|
75 |
|
|
_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 40- 43 */
|
76 |
|
|
_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 44- 47 */
|
77 |
|
|
_W|_A|_D, _W|_A|_D, _W|_A|_D, _W|_A|_D, /* 48- 51 */
|
78 |
|
|
_W|_A|_D, _W|_A|_D, _W|_A|_D, _W|_A|_D, /* 52- 55 */
|
79 |
|
|
_W|_A|_D, _W|_A|_D, _W|_A|_P, _W|_A|_P, /* 56- 59 */
|
80 |
|
|
_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 60- 63 */
|
81 |
|
|
_W|_A|_P, _W|_A|_U|_X, _W|_A|_U|_X, _W|_A|_U|_X, /* 64- 67 */
|
82 |
|
|
_W|_A|_U|_X, _W|_A|_U|_X, _W|_A|_U|_X, _W|_A|_U, /* 68- 71 */
|
83 |
|
|
_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 72- 75 */
|
84 |
|
|
_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 76- 79 */
|
85 |
|
|
_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 80- 83 */
|
86 |
|
|
_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_U, /* 84- 87 */
|
87 |
|
|
_W|_A|_U, _W|_A|_U, _W|_A|_U, _W|_A|_P, /* 88- 91 */
|
88 |
|
|
_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_P, /* 92- 95 */
|
89 |
|
|
_W|_A|_P, _W|_A|_L|_X, _W|_A|_L|_X, _W|_A|_L|_X, /* 96- 99 */
|
90 |
|
|
_W|_A|_L|_X, _W|_A|_L|_X, _W|_A|_L|_X, _W|_A|_L, /* 100-103 */
|
91 |
|
|
_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 104-107 */
|
92 |
|
|
_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 108-111 */
|
93 |
|
|
_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 112-115 */
|
94 |
|
|
_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_L, /* 116-119 */
|
95 |
|
|
_W|_A|_L, _W|_A|_L, _W|_A|_L, _W|_A|_P, /* 120-123 */
|
96 |
|
|
_W|_A|_P, _W|_A|_P, _W|_A|_P, _W|_A|_C, /* 124-127 */
|
97 |
|
|
_W, _W, _W, _W, /* 128-131 */
|
98 |
|
|
_W, _W, _W, _W, /* 132-135 */
|
99 |
|
|
_W, _W, _W, _W, /* 136-139 */
|
100 |
|
|
_W, _W, _W, _W, /* 140-143 */
|
101 |
|
|
_W, _W, _W, _W, /* 144-147 */
|
102 |
|
|
_W, _W, _W, _W, /* 148-151 */
|
103 |
|
|
_W, _W, _W, _W, /* 152-155 */
|
104 |
|
|
_W, _W, _W, _W, /* 156-159 */
|
105 |
|
|
_W|_S|_SP, _W|_P, _W|_P, _W|_P, /* 160-163 */
|
106 |
|
|
_W|_P, _W|_P, _W|_P, _W|_P, /* 164-167 */
|
107 |
|
|
_W|_P, _W|_P, _W|_P, _W|_P, /* 168-171 */
|
108 |
|
|
_W|_P, _W|_P, _W|_P, _W|_P, /* 172-175 */
|
109 |
|
|
_W|_P, _W|_P, _W|_P, _W|_P, /* 176-179 */
|
110 |
|
|
_W|_P, _W|_P, _W|_P, _W|_P, /* 180-183 */
|
111 |
|
|
_W|_P, _W|_P, _W|_P, _W|_P, /* 184-187 */
|
112 |
|
|
_W|_P, _W|_P, _W|_P, _W|_P, /* 188-191 */
|
113 |
|
|
_W|_U, _W|_U, _W|_U, _W|_U, /* 192-195 */
|
114 |
|
|
_W|_U, _W|_U, _W|_U, _W|_U, /* 196-199 */
|
115 |
|
|
_W|_U, _W|_U, _W|_U, _W|_U, /* 200-203 */
|
116 |
|
|
_W|_U, _W|_U, _W|_U, _W|_U, /* 204-207 */
|
117 |
|
|
_W|_U, _W|_U, _W|_U, _W|_U, /* 208-211 */
|
118 |
|
|
_W|_U, _W|_U, _W|_U, _W|_P, /* 212-215 */
|
119 |
|
|
_W|_U, _W|_U, _W|_U, _W|_U, /* 216-219 */
|
120 |
|
|
_W|_U, _W|_U, _W|_U, _W|_L, /* 220-223 */
|
121 |
|
|
_W|_L, _W|_L, _W|_L, _W|_L, /* 224-227 */
|
122 |
|
|
_W|_L, _W|_L, _W|_L, _W|_L, /* 228-231 */
|
123 |
|
|
_W|_L, _W|_L, _W|_L, _W|_L, /* 232-235 */
|
124 |
|
|
_W|_L, _W|_L, _W|_L, _W|_L, /* 236-239 */
|
125 |
|
|
_W|_L, _W|_L, _W|_L, _W|_L, /* 240-243 */
|
126 |
|
|
_W|_L, _W|_L, _W|_L, _W|_P, /* 244-247 */
|
127 |
|
|
_W|_L, _W|_L, _W|_L, _W|_L, /* 248-251 */
|
128 |
|
|
_W|_L, _W|_L, _W|_L, _W|_L}; /* 252-255 */
|
129 |
|
|
|
130 |
|
|
static inline int match_token(struct ts_fsm_token *t, u8 d)
|
131 |
|
|
{
|
132 |
|
|
if (t->type)
|
133 |
|
|
return (token_lookup_tbl[d] & t->type) != 0;
|
134 |
|
|
else
|
135 |
|
|
return t->value == d;
|
136 |
|
|
}
|
137 |
|
|
|
138 |
|
|
static unsigned int fsm_find(struct ts_config *conf, struct ts_state *state)
|
139 |
|
|
{
|
140 |
|
|
struct ts_fsm *fsm = ts_config_priv(conf);
|
141 |
|
|
struct ts_fsm_token *cur = NULL, *next;
|
142 |
|
|
unsigned int match_start, block_idx = 0, tok_idx;
|
143 |
|
|
unsigned block_len = 0, strict, consumed = state->offset;
|
144 |
|
|
const u8 *data;
|
145 |
|
|
|
146 |
|
|
#define GET_NEXT_BLOCK() \
|
147 |
|
|
({ consumed += block_idx; \
|
148 |
|
|
block_idx = 0; \
|
149 |
|
|
block_len = conf->get_next_block(consumed, &data, conf, state); })
|
150 |
|
|
|
151 |
|
|
#define TOKEN_MISMATCH() \
|
152 |
|
|
do { \
|
153 |
|
|
if (strict) \
|
154 |
|
|
goto no_match; \
|
155 |
|
|
block_idx++; \
|
156 |
|
|
goto startover; \
|
157 |
|
|
} while(0)
|
158 |
|
|
|
159 |
|
|
#define end_of_data() unlikely(block_idx >= block_len && !GET_NEXT_BLOCK())
|
160 |
|
|
|
161 |
|
|
if (end_of_data())
|
162 |
|
|
goto no_match;
|
163 |
|
|
|
164 |
|
|
strict = fsm->tokens[0].recur != TS_FSM_HEAD_IGNORE;
|
165 |
|
|
|
166 |
|
|
startover:
|
167 |
|
|
match_start = consumed + block_idx;
|
168 |
|
|
|
169 |
|
|
for (tok_idx = 0; tok_idx < fsm->ntokens; tok_idx++) {
|
170 |
|
|
cur = &fsm->tokens[tok_idx];
|
171 |
|
|
|
172 |
|
|
if (likely(tok_idx < (fsm->ntokens - 1)))
|
173 |
|
|
next = &fsm->tokens[tok_idx + 1];
|
174 |
|
|
else
|
175 |
|
|
next = NULL;
|
176 |
|
|
|
177 |
|
|
switch (cur->recur) {
|
178 |
|
|
case TS_FSM_SINGLE:
|
179 |
|
|
if (end_of_data())
|
180 |
|
|
goto no_match;
|
181 |
|
|
|
182 |
|
|
if (!match_token(cur, data[block_idx]))
|
183 |
|
|
TOKEN_MISMATCH();
|
184 |
|
|
break;
|
185 |
|
|
|
186 |
|
|
case TS_FSM_PERHAPS:
|
187 |
|
|
if (end_of_data() ||
|
188 |
|
|
!match_token(cur, data[block_idx]))
|
189 |
|
|
continue;
|
190 |
|
|
break;
|
191 |
|
|
|
192 |
|
|
case TS_FSM_MULTI:
|
193 |
|
|
if (end_of_data())
|
194 |
|
|
goto no_match;
|
195 |
|
|
|
196 |
|
|
if (!match_token(cur, data[block_idx]))
|
197 |
|
|
TOKEN_MISMATCH();
|
198 |
|
|
|
199 |
|
|
block_idx++;
|
200 |
|
|
/* fall through */
|
201 |
|
|
|
202 |
|
|
case TS_FSM_ANY:
|
203 |
|
|
if (next == NULL)
|
204 |
|
|
goto found_match;
|
205 |
|
|
|
206 |
|
|
if (end_of_data())
|
207 |
|
|
continue;
|
208 |
|
|
|
209 |
|
|
while (!match_token(next, data[block_idx])) {
|
210 |
|
|
if (!match_token(cur, data[block_idx]))
|
211 |
|
|
TOKEN_MISMATCH();
|
212 |
|
|
block_idx++;
|
213 |
|
|
if (end_of_data())
|
214 |
|
|
goto no_match;
|
215 |
|
|
}
|
216 |
|
|
continue;
|
217 |
|
|
|
218 |
|
|
/*
|
219 |
|
|
* Optimization: Prefer small local loop over jumping
|
220 |
|
|
* back and forth until garbage at head is munched.
|
221 |
|
|
*/
|
222 |
|
|
case TS_FSM_HEAD_IGNORE:
|
223 |
|
|
if (end_of_data())
|
224 |
|
|
continue;
|
225 |
|
|
|
226 |
|
|
while (!match_token(next, data[block_idx])) {
|
227 |
|
|
/*
|
228 |
|
|
* Special case, don't start over upon
|
229 |
|
|
* a mismatch, give the user the
|
230 |
|
|
* chance to specify the type of data
|
231 |
|
|
* allowed to be ignored.
|
232 |
|
|
*/
|
233 |
|
|
if (!match_token(cur, data[block_idx]))
|
234 |
|
|
goto no_match;
|
235 |
|
|
|
236 |
|
|
block_idx++;
|
237 |
|
|
if (end_of_data())
|
238 |
|
|
goto no_match;
|
239 |
|
|
}
|
240 |
|
|
|
241 |
|
|
match_start = consumed + block_idx;
|
242 |
|
|
continue;
|
243 |
|
|
}
|
244 |
|
|
|
245 |
|
|
block_idx++;
|
246 |
|
|
}
|
247 |
|
|
|
248 |
|
|
if (end_of_data())
|
249 |
|
|
goto found_match;
|
250 |
|
|
|
251 |
|
|
no_match:
|
252 |
|
|
return UINT_MAX;
|
253 |
|
|
|
254 |
|
|
found_match:
|
255 |
|
|
state->offset = consumed + block_idx;
|
256 |
|
|
return match_start;
|
257 |
|
|
}
|
258 |
|
|
|
259 |
|
|
static struct ts_config *fsm_init(const void *pattern, unsigned int len,
|
260 |
|
|
gfp_t gfp_mask)
|
261 |
|
|
{
|
262 |
|
|
int i, err = -EINVAL;
|
263 |
|
|
struct ts_config *conf;
|
264 |
|
|
struct ts_fsm *fsm;
|
265 |
|
|
struct ts_fsm_token *tokens = (struct ts_fsm_token *) pattern;
|
266 |
|
|
unsigned int ntokens = len / sizeof(*tokens);
|
267 |
|
|
size_t priv_size = sizeof(*fsm) + len;
|
268 |
|
|
|
269 |
|
|
if (len % sizeof(struct ts_fsm_token) || ntokens < 1)
|
270 |
|
|
goto errout;
|
271 |
|
|
|
272 |
|
|
for (i = 0; i < ntokens; i++) {
|
273 |
|
|
struct ts_fsm_token *t = &tokens[i];
|
274 |
|
|
|
275 |
|
|
if (t->type > TS_FSM_TYPE_MAX || t->recur > TS_FSM_RECUR_MAX)
|
276 |
|
|
goto errout;
|
277 |
|
|
|
278 |
|
|
if (t->recur == TS_FSM_HEAD_IGNORE &&
|
279 |
|
|
(i != 0 || i == (ntokens - 1)))
|
280 |
|
|
goto errout;
|
281 |
|
|
}
|
282 |
|
|
|
283 |
|
|
conf = alloc_ts_config(priv_size, gfp_mask);
|
284 |
|
|
if (IS_ERR(conf))
|
285 |
|
|
return conf;
|
286 |
|
|
|
287 |
|
|
fsm = ts_config_priv(conf);
|
288 |
|
|
fsm->ntokens = ntokens;
|
289 |
|
|
memcpy(fsm->tokens, pattern, len);
|
290 |
|
|
|
291 |
|
|
for (i = 0; i < fsm->ntokens; i++) {
|
292 |
|
|
struct ts_fsm_token *t = &fsm->tokens[i];
|
293 |
|
|
t->type = token_map[t->type];
|
294 |
|
|
}
|
295 |
|
|
|
296 |
|
|
return conf;
|
297 |
|
|
|
298 |
|
|
errout:
|
299 |
|
|
return ERR_PTR(err);
|
300 |
|
|
}
|
301 |
|
|
|
302 |
|
|
static void *fsm_get_pattern(struct ts_config *conf)
|
303 |
|
|
{
|
304 |
|
|
struct ts_fsm *fsm = ts_config_priv(conf);
|
305 |
|
|
return fsm->tokens;
|
306 |
|
|
}
|
307 |
|
|
|
308 |
|
|
static unsigned int fsm_get_pattern_len(struct ts_config *conf)
|
309 |
|
|
{
|
310 |
|
|
struct ts_fsm *fsm = ts_config_priv(conf);
|
311 |
|
|
return fsm->ntokens * sizeof(struct ts_fsm_token);
|
312 |
|
|
}
|
313 |
|
|
|
314 |
|
|
static struct ts_ops fsm_ops = {
|
315 |
|
|
.name = "fsm",
|
316 |
|
|
.find = fsm_find,
|
317 |
|
|
.init = fsm_init,
|
318 |
|
|
.get_pattern = fsm_get_pattern,
|
319 |
|
|
.get_pattern_len = fsm_get_pattern_len,
|
320 |
|
|
.owner = THIS_MODULE,
|
321 |
|
|
.list = LIST_HEAD_INIT(fsm_ops.list)
|
322 |
|
|
};
|
323 |
|
|
|
324 |
|
|
static int __init init_fsm(void)
|
325 |
|
|
{
|
326 |
|
|
return textsearch_register(&fsm_ops);
|
327 |
|
|
}
|
328 |
|
|
|
329 |
|
|
static void __exit exit_fsm(void)
|
330 |
|
|
{
|
331 |
|
|
textsearch_unregister(&fsm_ops);
|
332 |
|
|
}
|
333 |
|
|
|
334 |
|
|
MODULE_LICENSE("GPL");
|
335 |
|
|
|
336 |
|
|
module_init(init_fsm);
|
337 |
|
|
module_exit(exit_fsm);
|