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1 | /* -*-c-*- |
2 | * |
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3 | * Configuration parsing |
4 | * |
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5 | * (c) 1999 Straylight/Edgeware |
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6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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9 | * |
10 | * This file is part of the `fw' port forwarder. |
11 | * |
12 | * `fw' is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU General Public License as published by |
14 | * the Free Software Foundation; either version 2 of the License, or |
15 | * (at your option) any later version. |
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16 | * |
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17 | * `fw' is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU General Public License for more details. |
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21 | * |
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22 | * You should have received a copy of the GNU General Public License |
23 | * along with `fw'; if not, write to the Free Software Foundation, |
24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
25 | */ |
26 | |
47a7631f |
27 | #include "fw.h" |
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28 | |
29 | /*----- Main code ---------------------------------------------------------*/ |
30 | |
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31 | /* --- @conf_undelim@ --- * |
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32 | * |
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33 | * Arguments: @scanner *sc@ = pointer to scanner definition |
34 | * @const char *d, *dd@ = pointer to characters to escape |
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35 | * |
36 | * Returns: --- |
37 | * |
38 | * Use: Modifies the tokenizer. Characters in the first list will |
39 | * always be considered to begin a word. Characters in the |
40 | * second list will always be allowed to continue a word. |
41 | */ |
42 | |
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43 | void conf_undelim(scanner *sc, const char *d, const char *dd) |
44 | { |
45 | sc->wbegin = d; |
46 | sc->wcont = dd; |
47 | } |
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48 | |
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49 | /* --- @token@ --- * |
50 | * |
51 | * Arguments: @scanner *sc@ = pointer to scanner definition |
52 | * |
53 | * Returns: Type of token scanned. |
54 | * |
55 | * Use: Reads the next token from the character scanner. |
56 | */ |
57 | |
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58 | int token(scanner *sc) |
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59 | { |
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60 | #define SELFDELIM \ |
61 | '{': case '}': case '/': case ',': \ |
62 | case '=': case ':': case ';': \ |
63 | case '.': case '[': case ']' |
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64 | |
65 | int ch; |
66 | |
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67 | DRESET(&sc->d); |
68 | |
69 | /* --- Main tokenization --- */ |
70 | |
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71 | for (;;) { |
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72 | ch = scan(sc); |
73 | |
74 | /* --- Deal with pushed-back tokens --- */ |
75 | |
76 | if (sc->head->tok) { |
77 | dstr_puts(&sc->d, sc->head->tok); |
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78 | xfree(sc->head->tok); |
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79 | sc->head->tok = 0; |
80 | sc->t = sc->head->t; |
81 | goto done; |
82 | } |
83 | |
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84 | else if (isspace(ch)) |
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85 | ; |
86 | else switch (ch) { |
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87 | |
88 | /* --- End of file --- */ |
89 | |
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90 | case EOF: |
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91 | sc->t = CTOK_EOF; |
92 | goto done; |
93 | |
94 | /* --- Comment character --- */ |
95 | |
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96 | case '#': |
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97 | do ch = scan(sc); while (ch != EOF && ch != '\n'); |
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98 | break; |
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99 | |
100 | /* --- Various self-delimiting characters --- */ |
101 | |
102 | case SELFDELIM: |
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103 | if (!sc->wbegin || strchr(sc->wbegin, ch) == 0) { |
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104 | dstr_putc(&sc->d, ch); |
105 | dstr_putz(&sc->d); |
106 | sc->t = ch; |
107 | goto done; |
108 | } |
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109 | |
110 | /* --- Bare words --- * |
111 | * |
112 | * These aren't as bare any more. You can now backslash-escape |
113 | * individual characters, and enclose sections in double-quotes. |
114 | */ |
115 | |
116 | default: { |
117 | int q = 0; |
118 | |
119 | for (;;) { |
120 | switch (ch) { |
121 | case EOF: |
122 | goto word; |
123 | case '\\': |
124 | ch = scan(sc); |
125 | if (ch == EOF) |
126 | goto word; |
127 | DPUTC(&sc->d, ch); |
128 | break; |
129 | case '\"': |
130 | q = !q; |
131 | break; |
132 | case SELFDELIM: |
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133 | if (q || (sc->wcont && strchr(sc->wcont, ch))) |
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134 | goto insert; |
135 | goto word; |
136 | default: |
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137 | if (!q && isspace(ch)) |
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138 | goto word; |
139 | insert: |
140 | DPUTC(&sc->d, ch); |
141 | break; |
142 | } |
143 | ch = scan(sc); |
144 | } |
145 | word: |
146 | unscan(sc, ch); |
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147 | DPUTZ(&sc->d); |
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148 | sc->t = CTOK_WORD; |
149 | goto done; |
150 | } |
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151 | } |
152 | } |
153 | |
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154 | done: |
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155 | return (sc->t); |
156 | } |
157 | |
158 | /* --- @pushback@ --- * |
159 | * |
160 | * Arguments: @scanner *sc@ = pointer to scanner definition |
161 | * |
162 | * Returns: --- |
163 | * |
164 | * Use: Pushes the current token back. This is normally a precursor |
165 | * to pushing a new scanner source. |
166 | */ |
167 | |
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168 | void pushback(scanner *sc) |
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169 | { |
170 | sc->head->tok = xstrdup(sc->d.buf); |
171 | sc->head->t = sc->t; |
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172 | } |
173 | |
174 | /* --- @error@ --- * |
175 | * |
176 | * Arguments: @scanner *sc@ = pointer to scanner definition |
177 | * @const char *msg@ = message skeleton string |
178 | * @...@ = extra arguments for the skeleton |
179 | * |
180 | * Returns: Doesn't |
181 | * |
182 | * Use: Reports an error at the current scanner location. |
183 | */ |
184 | |
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185 | void error(scanner *sc, const char *msg, ...) |
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186 | { |
187 | va_list ap; |
188 | va_start(ap, msg); |
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189 | fprintf(stderr, "%s: %s:%i: ", QUIS, sc->head->src, sc->head->line); |
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190 | vfprintf(stderr, msg, ap); |
191 | fputc('\n', stderr); |
192 | exit(1); |
193 | } |
194 | |
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195 | /* --- @conf_enum@ --- * |
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196 | * |
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197 | * Arguments: @scanner *sc@ = pointer to a scanner object |
198 | * @const char *list@ = comma-separated things to allow |
199 | * @unsigned f@ = flags for the search |
200 | * @const char *err@ = error message if not found |
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201 | * |
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202 | * Returns: Index into list, zero-based, or @-1@. |
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203 | * |
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204 | * Use: Checks whether the current token is a string which matches |
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205 | * one of the comma-separated items given. The return value is |
206 | * the index (zero-based) of the matched string in the list. |
207 | * |
208 | * The flags control the behaviour if no exact match is found. |
209 | * If @ENUM_ABBREV@ is set, and the current token is a left |
210 | * substring of exactly one of the possibilities, then that one |
211 | * is chosen. If @ENUM_NONE@ is set, the value @-1@ is |
212 | * returned; otherwise an error is reported and the program is |
213 | * terminated. |
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214 | */ |
215 | |
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216 | int conf_enum(scanner *sc, const char *list, unsigned f, const char *err) |
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217 | { |
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218 | const char *p, *q; |
219 | int chosen = -1; |
220 | int ok; |
221 | int index; |
222 | |
223 | /* --- Make sure it's a string --- */ |
224 | |
225 | if (sc->t != CTOK_WORD) |
226 | error(sc, "parse error, expected %s", err); |
227 | |
228 | /* --- Grind through the list --- */ |
229 | |
230 | q = sc->d.buf; |
231 | ok = 1; |
232 | index = 0; |
233 | p = list; |
234 | for (;;) { |
235 | switch (*p) { |
236 | case 0: |
237 | if (ok && !*q) { |
238 | token(sc); |
239 | return (index); |
240 | } else if (chosen != -1) { |
241 | token(sc); |
242 | return (chosen); |
243 | } |
244 | else if (f & ENUM_NONE) |
245 | return (-1); |
246 | else |
247 | error(sc, "unknown %s `%s'", err, sc->d.buf); |
248 | break; |
249 | case ',': |
250 | if (ok && !*q) { |
251 | token(sc); |
252 | return (index); |
253 | } |
254 | ok = 1; |
255 | q = sc->d.buf; |
256 | index++; |
257 | break; |
258 | default: |
259 | if (!ok) |
260 | break; |
261 | if ((f & ENUM_ABBREV) && !*q) { |
262 | if (chosen != -1) |
263 | error(sc, "ambiguous %s `%s'", err, sc->d.buf); |
264 | chosen = index; |
265 | ok = 0; |
266 | } |
267 | if (*p == *q) |
268 | q++; |
269 | else |
270 | ok = 0; |
271 | break; |
272 | } |
273 | p++; |
274 | } |
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275 | } |
276 | |
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277 | /* --- @conf_prefix@ --- * |
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278 | * |
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279 | * Arguments: @scanner *sc@ = pointer to a scanner object |
280 | * @const char *p@ = pointer to prefix string to check |
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281 | * |
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282 | * Returns: Nonzero if the prefix matches. |
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283 | * |
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284 | * Use: If the current token is a word matching the given prefix |
285 | * string, then it and an optional `.' character are removed and |
286 | * a nonzero result is returned. Otherwise the current token is |
287 | * left as it is, and zero is returned. |
288 | * |
289 | * Typical options parsing code would remove an expected prefix, |
290 | * scan an option anyway (since qualifying prefixes are |
291 | * optional) and if a match is found, claim the option. If no |
292 | * match is found, and a prefix was stripped, then an error |
293 | * should be reported. |
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294 | */ |
295 | |
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296 | int conf_prefix(scanner *sc, const char *p) |
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297 | { |
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298 | if (sc->t == CTOK_WORD && strcmp(p, sc->d.buf) == 0) { |
299 | token(sc); |
300 | if (sc->t == '.') |
301 | token(sc); |
302 | return (1); |
303 | } |
304 | return (0); |
305 | } |
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306 | |
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307 | /* --- @conf_name@ --- * |
308 | * |
309 | * Arguments: @scanner *sc@ = pointer to scanner |
310 | * @char delim@ = delimiter character to look for |
311 | * @dstr *d@ = pointer to dynamic string for output |
312 | * |
313 | * Returns: --- |
314 | * |
315 | * Use: Reads in a compound name consisting of words separated by |
316 | * delimiters. Leading and trailing delimiters are permitted, |
317 | * although they'll probably cause confusion if used. The name |
318 | * may be enclosed in square brackets if that helps at all. |
319 | * |
320 | * Examples of compound names are filenames (delimited by `/') |
321 | * and IP addresses (delimited by `.'). |
322 | */ |
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323 | |
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324 | void conf_name(scanner *sc, char delim, dstr *d) |
325 | { |
326 | unsigned f = 0; |
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327 | |
328 | #define f_ok 1u |
329 | #define f_bra 2u |
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330 | |
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331 | /* --- Read an optional opening bracket --- */ |
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332 | |
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333 | if (sc->t == '[') { |
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334 | token(sc); |
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335 | f |= f_bra | f_ok; |
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336 | } |
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337 | |
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338 | /* --- Do the main reading sequence --- */ |
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339 | |
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340 | do { |
341 | if (sc->t == delim) { |
342 | DPUTC(d, delim); |
343 | f |= f_ok; |
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344 | token(sc); |
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345 | } |
346 | if (sc->t == CTOK_WORD) { |
347 | DPUTD(d, &sc->d); |
348 | f |= f_ok; |
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349 | token(sc); |
350 | } |
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351 | } while (sc->t == delim); |
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352 | |
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353 | /* --- Check that the string was OK --- */ |
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354 | |
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355 | if (!(f & f_ok)) |
356 | error(sc, "parse error, name expected"); |
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357 | |
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358 | /* --- Read a closing bracket --- */ |
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359 | |
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360 | if (f & f_bra) { |
361 | if (sc->t == ']') |
362 | token(sc); |
363 | else |
364 | error(sc, "parse error, missing `]'"); |
365 | } |
366 | DPUTZ(d); |
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367 | |
368 | #undef f_ok |
369 | #undef f_bra |
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370 | } |
371 | |
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372 | /*----- That's all, folks -------------------------------------------------*/ |