| 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);
|