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