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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: conf.h,v 1.7 2002/02/22 23:42:56 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 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: conf.h,v $ |
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32 | * Revision 1.7 2002/02/22 23:42:56 mdw |
33 | * `fw'-specific configuration code moved out. This file might become part |
34 | * of a library some day. |
35 | * |
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36 | * Revision 1.6 2002/01/13 14:48:16 mdw |
37 | * Make delimiters be a property of a scanner. Change the delimiter- |
38 | * changing functions' names. |
39 | * |
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40 | * Revision 1.5 1999/10/22 22:46:44 mdw |
41 | * Improve documentation for conf_enum. |
42 | * |
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43 | * Revision 1.4 1999/08/19 18:32:48 mdw |
44 | * Improve lexical analysis. In particular, `chmod' patterns don't have to |
45 | * be quoted any more. |
46 | * |
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47 | * Revision 1.3 1999/07/27 18:30:14 mdw |
48 | * Improve documentation and layout for @CONF_BEGIN@ and friends. Remove |
49 | * irritating warning about unused label by introducing a spurious `goto'. |
50 | * |
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51 | * Revision 1.2 1999/07/26 23:28:39 mdw |
52 | * Major reconstruction work for new design. |
53 | * |
54 | * Revision 1.1.1.1 1999/07/01 08:56:23 mdw |
55 | * Initial revision. |
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56 | * |
57 | */ |
58 | |
59 | #ifndef CONF_H |
60 | #define CONF_H |
61 | |
62 | #ifdef __cplusplus |
63 | extern "C" { |
64 | #endif |
65 | |
66 | /*----- Header files ------------------------------------------------------*/ |
67 | |
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68 | #include <mLib/dstr.h> |
69 | |
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70 | #ifndef SCAN_H |
71 | # include "scan.h" |
72 | #endif |
73 | |
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74 | /*----- Magic numbers -----------------------------------------------------*/ |
75 | |
76 | #define CTOK_EOF (-1) |
77 | #define CTOK_WORD 256 |
78 | |
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79 | /*----- Functions provided ------------------------------------------------*/ |
80 | |
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81 | /* --- @conf_undelim@ --- * |
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82 | * |
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83 | * Arguments: @scanner *sc@ = pointer to scanner definition |
84 | * @const char *d, *dd@ = pointer to characters to escape |
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85 | * |
86 | * Returns: --- |
87 | * |
88 | * Use: Modifies the tokenizer. Characters in the first list will |
89 | * always be considered to begin a word. Characters in the |
90 | * second list will always be allowed to continue a word. |
91 | */ |
92 | |
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93 | extern void conf_undelim(scanner */*sc*/, |
94 | const char */*d*/, const char */*dd*/); |
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95 | |
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96 | /* --- @token@ --- * |
97 | * |
98 | * Arguments: @scanner *sc@ = pointer to scanner definition |
99 | * |
100 | * Returns: Type of token scanned. |
101 | * |
102 | * Use: Reads the next token from the character scanner. |
103 | */ |
104 | |
105 | extern int token(scanner */*sc*/); |
106 | |
107 | /* --- @error@ --- * |
108 | * |
109 | * Arguments: @scanner *sc@ = pointer to scanner definition |
110 | * @const char *msg@ = message skeleton string |
111 | * @...@ = extra arguments for the skeleton |
112 | * |
113 | * Returns: Doesn't |
114 | * |
115 | * Use: Reports an error at the current scanner location. |
116 | */ |
117 | |
118 | extern void error(scanner */*sc*/, const char */*msg*/, ...); |
119 | |
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120 | /* --- @pushback@ --- * |
121 | * |
122 | * Arguments: @scanner *sc@ = pointer to scanner definition |
123 | * |
124 | * Returns: --- |
125 | * |
126 | * Use: Pushes the current token back. This is normally a precursor |
127 | * to pushing a new scanner source. |
128 | */ |
129 | |
130 | extern void pushback(scanner */*sc*/); |
131 | |
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132 | /* --- @conf_enum@ --- * |
133 | * |
134 | * Arguments: @scanner *sc@ = pointer to a scanner object |
135 | * @const char *list@ = comma-separated things to allow |
136 | * @unsigned @f = flags for the search |
137 | * @const char *err@ = error message if not found |
138 | * |
139 | * Returns: Index into list, zero-based, or @-1@. |
140 | * |
141 | * Use: Checks whether the current token is a string which matches |
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142 | * one of the comma-separated items given. The return value is |
143 | * the index (zero-based) of the matched string in the list. |
144 | * |
145 | * The flags control the behaviour if no exact match is found. |
146 | * If @ENUM_ABBREV@ is set, and the current token is a left |
147 | * substring of exactly one of the possibilities, then that one |
148 | * is chosen. If @ENUM_NONE@ is set, the value @-1@ is |
149 | * returned; otherwise an error is reported and the program is |
150 | * terminated. |
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151 | */ |
152 | |
153 | #define ENUM_ABBREV 1u |
154 | #define ENUM_NONE 2u |
155 | |
156 | extern int conf_enum(scanner */*sc*/, const char */*list*/, |
157 | unsigned /*flags*/, const char */*err*/); |
158 | |
159 | /* --- @conf_prefix@ --- * |
160 | * |
161 | * Arguments: @scanner *sc@ = pointer to a scanner object |
162 | * @const char *p@ = pointer to prefix string to check |
163 | * |
164 | * Returns: Nonzero if the prefix matches. |
165 | * |
166 | * Use: If the current token is a word matching the given prefix |
167 | * string, then it and an optional `.' character are removed and |
168 | * a nonzero result is returned. Otherwise the current token is |
169 | * left as it is, and zero is returned. |
170 | * |
171 | * Typical options parsing code would remove an expected prefix, |
172 | * scan an option anyway (since qualifying prefixes are |
173 | * optional) and if a match is found, claim the option. If no |
174 | * match is found, and a prefix was stripped, then an error |
175 | * should be reported. |
176 | */ |
177 | |
178 | extern int conf_prefix(scanner */*sc*/, const char */*p*/); |
179 | |
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180 | /* --- @CONF_BEGIN@, @CONF_END@ --- * |
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181 | * |
182 | * Arguments: @sc@ = scanner to read from |
183 | * @prefix@ = prefix to scan for |
184 | * @desc@ = description of what we're parsing |
185 | * |
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186 | * Use: Bracket an options parsing routine. The current token is |
187 | * checked to see whether it matches the prefix. If so, it is |
188 | * removed and the following token examined. If that's a `.' |
189 | * then it's removed. If it's a `{' then the enclosed |
190 | * option-parsing code is executed in a loop until a matching |
191 | * '}' is found. If the options parser doesn't accept an |
192 | * option, the behaviour is dependent on whether a prefix was |
193 | * seen: if so, an error is reported; otherwse a zero return is |
194 | * made. |
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195 | */ |
196 | |
197 | #define CS_PLAIN 0 |
198 | #define CS_PREFIX 1 |
199 | #define CS_BRACE 2 |
200 | #define CS_UNKNOWN 3 |
201 | |
202 | #define CONF_BEGIN(sc, prefix, desc) do { \ |
203 | scanner *_conf_sc = (sc); \ |
204 | const char *_conf_desc = (desc); \ |
205 | int _conf_state = CS_PLAIN; \ |
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206 | \ |
207 | /* --- Read the initial prefix --- */ \ |
208 | \ |
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209 | if (_conf_sc->t == CTOK_WORD && \ |
210 | strcmp(_conf_sc->d.buf, (prefix)) == 0) { \ |
211 | token(_conf_sc); \ |
212 | _conf_state = CS_PREFIX; \ |
213 | if (_conf_sc->t == '.') \ |
214 | token(_conf_sc); \ |
215 | else if (_conf_sc->t == '{') { \ |
216 | token(_conf_sc); \ |
217 | _conf_state = CS_BRACE; \ |
218 | } \ |
219 | } \ |
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220 | \ |
221 | /* --- Ensure the next token is a word --- */ \ |
222 | \ |
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223 | if (_conf_sc->t != CTOK_WORD) \ |
224 | error(_conf_sc, "parse error, expected option keyword"); \ |
225 | do { |
226 | |
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227 | #define CONF_END \ |
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228 | \ |
229 | /* --- Reject an option --- * \ |
230 | * \ |
231 | * We could get here as a result of an explicit @CONF_REJECT@ or \ |
232 | * because the option wasn't accepted. \ |
233 | */ \ |
234 | \ |
235 | goto _conf_reject; \ |
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236 | _conf_reject: \ |
237 | if (_conf_state == CS_PLAIN) \ |
238 | _conf_state = CS_UNKNOWN; \ |
239 | else { \ |
240 | error(_conf_sc, "unknown %s option `%s'", \ |
241 | _conf_desc, _conf_sc->d.buf); \ |
242 | } \ |
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243 | \ |
244 | /* --- Accept an option --- * \ |
245 | * \ |
246 | * It's safe to drop through from above. Either an error will have \ |
247 | * been reported, or the state is not @CS_BRACE@. \ |
248 | */ \ |
249 | \ |
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250 | _conf_accept: \ |
251 | if (_conf_state == CS_BRACE && _conf_sc->t == ';') \ |
252 | token(_conf_sc); \ |
253 | } while (_conf_state == CS_BRACE && _conf_sc->t == CTOK_WORD); \ |
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254 | \ |
255 | /* --- Check for a closing brace --- */ \ |
256 | \ |
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257 | if (_conf_state == CS_BRACE) { \ |
258 | if (_conf_sc->t == '}') \ |
259 | token(_conf_sc); \ |
260 | else \ |
261 | error(_conf_sc, "parse error, expected `}'"); \ |
262 | } \ |
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263 | \ |
264 | /* --- Return an appropriate value --- */ \ |
265 | \ |
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266 | return (_conf_state != CS_UNKNOWN); \ |
267 | } while (0) |
268 | |
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269 | /* --- @CONF_ACCEPT@, @CONF_REJECT@ --- * |
270 | * |
271 | * Arguments: --- |
272 | * |
273 | * Use: Within an options parser (between @CONF_BEGIN@ and |
274 | * @CONF_END@), accept or reject an option. |
275 | */ |
276 | |
277 | #define CONF_ACCEPT goto _conf_accept |
278 | #define CONF_REJECT goto _conf_reject |
279 | |
280 | /* --- @CONF_QUAL@ --- * |
281 | * |
282 | * Arguments: --- |
283 | * |
284 | * Use: Evaluates to a nonzero value if the current option is |
285 | * qualified. This can be used to decide whether abbreviations |
286 | * for options should be accepted. |
287 | */ |
288 | |
289 | #define CONF_QUAL (_conf_state != CS_PLAIN) |
290 | |
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291 | /* --- @conf_name@ --- * |
292 | * |
293 | * Arguments: @scanner *sc@ = pointer to scanner |
294 | * @char delim@ = delimiter character to look for |
295 | * @dstr *d@ = pointer to dynamic string for output |
296 | * |
297 | * Returns: --- |
298 | * |
299 | * Use: Reads in a compound name consisting of words separated by |
300 | * delimiters. Leading and trailing delimiters are permitted, |
301 | * although they'll probably cause confusion if used. The name |
302 | * may be enclosed in square brackets if that helps at all. |
303 | * |
304 | * Examples of compound names are filenames (delimited by `/') |
305 | * and IP addresses (delimited by `.'). |
306 | */ |
307 | |
308 | extern void conf_name(scanner */*sc*/, char /*delim*/, dstr */*d*/); |
309 | |
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310 | /*----- That's all, folks -------------------------------------------------*/ |
311 | |
312 | #ifdef __cplusplus |
313 | } |
314 | #endif |
315 | |
316 | #endif |