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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: conf.c,v 1.11 2004/04/08 01:36:25 mdw Exp $ |
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4 | * |
5 | * Configuration parsing |
6 | * |
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7 | * (c) 1999 Straylight/Edgeware |
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8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the `fw' port forwarder. |
13 | * |
14 | * `fw' is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
19 | * `fw' is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
25 | * along with `fw'; if not, write to the Free Software Foundation, |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | */ |
28 | |
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29 | /*----- Header files ------------------------------------------------------*/ |
30 | |
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31 | #include <ctype.h> |
32 | #include <errno.h> |
33 | #include <stdarg.h> |
34 | #include <stdio.h> |
35 | #include <stdlib.h> |
36 | #include <string.h> |
37 | |
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38 | #include <mLib/dstr.h> |
39 | #include <mLib/quis.h> |
40 | #include <mLib/report.h> |
41 | |
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42 | #include "conf.h" |
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43 | #include "scan.h" |
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44 | |
45 | /*----- Main code ---------------------------------------------------------*/ |
46 | |
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47 | /* --- @conf_undelim@ --- * |
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48 | * |
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49 | * Arguments: @scanner *sc@ = pointer to scanner definition |
50 | * @const char *d, *dd@ = pointer to characters to escape |
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51 | * |
52 | * Returns: --- |
53 | * |
54 | * Use: Modifies the tokenizer. Characters in the first list will |
55 | * always be considered to begin a word. Characters in the |
56 | * second list will always be allowed to continue a word. |
57 | */ |
58 | |
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59 | void conf_undelim(scanner *sc, const char *d, const char *dd) |
60 | { |
61 | sc->wbegin = d; |
62 | sc->wcont = dd; |
63 | } |
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64 | |
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65 | /* --- @token@ --- * |
66 | * |
67 | * Arguments: @scanner *sc@ = pointer to scanner definition |
68 | * |
69 | * Returns: Type of token scanned. |
70 | * |
71 | * Use: Reads the next token from the character scanner. |
72 | */ |
73 | |
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74 | int token(scanner *sc) |
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75 | { |
61e3dbdf |
76 | #define SELFDELIM \ |
77 | '{': case '}': case '/': case ',': \ |
78 | case '=': case ':': case ';': \ |
79 | case '.': case '[': case ']' |
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80 | |
81 | int ch; |
82 | |
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83 | DRESET(&sc->d); |
84 | |
85 | /* --- Main tokenization --- */ |
86 | |
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87 | for (;;) { |
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88 | ch = scan(sc); |
89 | |
90 | /* --- Deal with pushed-back tokens --- */ |
91 | |
92 | if (sc->head->tok) { |
93 | dstr_puts(&sc->d, sc->head->tok); |
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94 | xfree(sc->head->tok); |
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95 | sc->head->tok = 0; |
96 | sc->t = sc->head->t; |
97 | goto done; |
98 | } |
99 | |
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100 | else if (isspace(ch)) |
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101 | ; |
102 | else switch (ch) { |
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103 | |
104 | /* --- End of file --- */ |
105 | |
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106 | case EOF: |
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107 | sc->t = CTOK_EOF; |
108 | goto done; |
109 | |
110 | /* --- Comment character --- */ |
111 | |
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112 | case '#': |
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113 | do ch = scan(sc); while (ch != EOF && ch != '\n'); |
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114 | break; |
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115 | |
116 | /* --- Various self-delimiting characters --- */ |
117 | |
118 | case SELFDELIM: |
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119 | if (!sc->wbegin || strchr(sc->wbegin, ch) == 0) { |
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120 | dstr_putc(&sc->d, ch); |
121 | dstr_putz(&sc->d); |
122 | sc->t = ch; |
123 | goto done; |
124 | } |
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125 | |
126 | /* --- Bare words --- * |
127 | * |
128 | * These aren't as bare any more. You can now backslash-escape |
129 | * individual characters, and enclose sections in double-quotes. |
130 | */ |
131 | |
132 | default: { |
133 | int q = 0; |
134 | |
135 | for (;;) { |
136 | switch (ch) { |
137 | case EOF: |
138 | goto word; |
139 | case '\\': |
140 | ch = scan(sc); |
141 | if (ch == EOF) |
142 | goto word; |
143 | DPUTC(&sc->d, ch); |
144 | break; |
145 | case '\"': |
146 | q = !q; |
147 | break; |
148 | case SELFDELIM: |
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149 | if (q || (sc->wcont && strchr(sc->wcont, ch))) |
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150 | goto insert; |
151 | goto word; |
152 | default: |
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153 | if (!q && isspace(ch)) |
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154 | goto word; |
155 | insert: |
156 | DPUTC(&sc->d, ch); |
157 | break; |
158 | } |
159 | ch = scan(sc); |
160 | } |
161 | word: |
162 | unscan(sc, ch); |
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163 | DPUTZ(&sc->d); |
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164 | sc->t = CTOK_WORD; |
165 | goto done; |
166 | } |
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167 | } |
168 | } |
169 | |
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170 | done: |
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171 | return (sc->t); |
172 | } |
173 | |
174 | /* --- @pushback@ --- * |
175 | * |
176 | * Arguments: @scanner *sc@ = pointer to scanner definition |
177 | * |
178 | * Returns: --- |
179 | * |
180 | * Use: Pushes the current token back. This is normally a precursor |
181 | * to pushing a new scanner source. |
182 | */ |
183 | |
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184 | void pushback(scanner *sc) |
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185 | { |
186 | sc->head->tok = xstrdup(sc->d.buf); |
187 | sc->head->t = sc->t; |
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188 | } |
189 | |
190 | /* --- @error@ --- * |
191 | * |
192 | * Arguments: @scanner *sc@ = pointer to scanner definition |
193 | * @const char *msg@ = message skeleton string |
194 | * @...@ = extra arguments for the skeleton |
195 | * |
196 | * Returns: Doesn't |
197 | * |
198 | * Use: Reports an error at the current scanner location. |
199 | */ |
200 | |
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201 | void error(scanner *sc, const char *msg, ...) |
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202 | { |
203 | va_list ap; |
204 | va_start(ap, msg); |
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205 | fprintf(stderr, "%s: %s:%i: ", QUIS, sc->head->src, sc->head->line); |
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206 | vfprintf(stderr, msg, ap); |
207 | fputc('\n', stderr); |
208 | exit(1); |
209 | } |
210 | |
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211 | /* --- @conf_enum@ --- * |
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212 | * |
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213 | * Arguments: @scanner *sc@ = pointer to a scanner object |
214 | * @const char *list@ = comma-separated things to allow |
215 | * @unsigned f@ = flags for the search |
216 | * @const char *err@ = error message if not found |
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217 | * |
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218 | * Returns: Index into list, zero-based, or @-1@. |
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219 | * |
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220 | * Use: Checks whether the current token is a string which matches |
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221 | * one of the comma-separated items given. The return value is |
222 | * the index (zero-based) of the matched string in the list. |
223 | * |
224 | * The flags control the behaviour if no exact match is found. |
225 | * If @ENUM_ABBREV@ is set, and the current token is a left |
226 | * substring of exactly one of the possibilities, then that one |
227 | * is chosen. If @ENUM_NONE@ is set, the value @-1@ is |
228 | * returned; otherwise an error is reported and the program is |
229 | * terminated. |
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230 | */ |
231 | |
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232 | int conf_enum(scanner *sc, const char *list, unsigned f, const char *err) |
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233 | { |
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234 | const char *p, *q; |
235 | int chosen = -1; |
236 | int ok; |
237 | int index; |
238 | |
239 | /* --- Make sure it's a string --- */ |
240 | |
241 | if (sc->t != CTOK_WORD) |
242 | error(sc, "parse error, expected %s", err); |
243 | |
244 | /* --- Grind through the list --- */ |
245 | |
246 | q = sc->d.buf; |
247 | ok = 1; |
248 | index = 0; |
249 | p = list; |
250 | for (;;) { |
251 | switch (*p) { |
252 | case 0: |
253 | if (ok && !*q) { |
254 | token(sc); |
255 | return (index); |
256 | } else if (chosen != -1) { |
257 | token(sc); |
258 | return (chosen); |
259 | } |
260 | else if (f & ENUM_NONE) |
261 | return (-1); |
262 | else |
263 | error(sc, "unknown %s `%s'", err, sc->d.buf); |
264 | break; |
265 | case ',': |
266 | if (ok && !*q) { |
267 | token(sc); |
268 | return (index); |
269 | } |
270 | ok = 1; |
271 | q = sc->d.buf; |
272 | index++; |
273 | break; |
274 | default: |
275 | if (!ok) |
276 | break; |
277 | if ((f & ENUM_ABBREV) && !*q) { |
278 | if (chosen != -1) |
279 | error(sc, "ambiguous %s `%s'", err, sc->d.buf); |
280 | chosen = index; |
281 | ok = 0; |
282 | } |
283 | if (*p == *q) |
284 | q++; |
285 | else |
286 | ok = 0; |
287 | break; |
288 | } |
289 | p++; |
290 | } |
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291 | } |
292 | |
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293 | /* --- @conf_prefix@ --- * |
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294 | * |
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295 | * Arguments: @scanner *sc@ = pointer to a scanner object |
296 | * @const char *p@ = pointer to prefix string to check |
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297 | * |
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298 | * Returns: Nonzero if the prefix matches. |
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299 | * |
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300 | * Use: If the current token is a word matching the given prefix |
301 | * string, then it and an optional `.' character are removed and |
302 | * a nonzero result is returned. Otherwise the current token is |
303 | * left as it is, and zero is returned. |
304 | * |
305 | * Typical options parsing code would remove an expected prefix, |
306 | * scan an option anyway (since qualifying prefixes are |
307 | * optional) and if a match is found, claim the option. If no |
308 | * match is found, and a prefix was stripped, then an error |
309 | * should be reported. |
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310 | */ |
311 | |
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312 | int conf_prefix(scanner *sc, const char *p) |
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313 | { |
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314 | if (sc->t == CTOK_WORD && strcmp(p, sc->d.buf) == 0) { |
315 | token(sc); |
316 | if (sc->t == '.') |
317 | token(sc); |
318 | return (1); |
319 | } |
320 | return (0); |
321 | } |
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322 | |
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323 | /* --- @conf_name@ --- * |
324 | * |
325 | * Arguments: @scanner *sc@ = pointer to scanner |
326 | * @char delim@ = delimiter character to look for |
327 | * @dstr *d@ = pointer to dynamic string for output |
328 | * |
329 | * Returns: --- |
330 | * |
331 | * Use: Reads in a compound name consisting of words separated by |
332 | * delimiters. Leading and trailing delimiters are permitted, |
333 | * although they'll probably cause confusion if used. The name |
334 | * may be enclosed in square brackets if that helps at all. |
335 | * |
336 | * Examples of compound names are filenames (delimited by `/') |
337 | * and IP addresses (delimited by `.'). |
338 | */ |
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339 | |
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340 | void conf_name(scanner *sc, char delim, dstr *d) |
341 | { |
342 | unsigned f = 0; |
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343 | |
344 | #define f_ok 1u |
345 | #define f_bra 2u |
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346 | |
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347 | /* --- Read an optional opening bracket --- */ |
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348 | |
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349 | if (sc->t == '[') { |
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350 | token(sc); |
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351 | f |= f_bra | f_ok; |
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352 | } |
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353 | |
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354 | /* --- Do the main reading sequence --- */ |
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355 | |
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356 | do { |
357 | if (sc->t == delim) { |
358 | DPUTC(d, delim); |
359 | f |= f_ok; |
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360 | token(sc); |
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361 | } |
362 | if (sc->t == CTOK_WORD) { |
363 | DPUTD(d, &sc->d); |
364 | f |= f_ok; |
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365 | token(sc); |
366 | } |
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367 | } while (sc->t == delim); |
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368 | |
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369 | /* --- Check that the string was OK --- */ |
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370 | |
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371 | if (!(f & f_ok)) |
372 | error(sc, "parse error, name expected"); |
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373 | |
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374 | /* --- Read a closing bracket --- */ |
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375 | |
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376 | if (f & f_bra) { |
377 | if (sc->t == ']') |
378 | token(sc); |
379 | else |
380 | error(sc, "parse error, missing `]'"); |
381 | } |
382 | DPUTZ(d); |
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383 | |
384 | #undef f_ok |
385 | #undef f_bra |
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386 | } |
387 | |
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388 | /*----- That's all, folks -------------------------------------------------*/ |