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