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Conditional compilation for @getnetbyname@, since Cygwin doesn't have
[fwd] / conf.h
1 /* -*-c-*-
2 *
3 * $Id: conf.h,v 1.6 2002/01/13 14:48:16 mdw Exp $
4 *
5 * Configuration parsing
6 *
7 * (c) 1999 Straylight/Edgeware
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 $
32 * Revision 1.6 2002/01/13 14:48:16 mdw
33 * Make delimiters be a property of a scanner. Change the delimiter-
34 * changing functions' names.
35 *
36 * Revision 1.5 1999/10/22 22:46:44 mdw
37 * Improve documentation for conf_enum.
38 *
39 * Revision 1.4 1999/08/19 18:32:48 mdw
40 * Improve lexical analysis. In particular, `chmod' patterns don't have to
41 * be quoted any more.
42 *
43 * Revision 1.3 1999/07/27 18:30:14 mdw
44 * Improve documentation and layout for @CONF_BEGIN@ and friends. Remove
45 * irritating warning about unused label by introducing a spurious `goto'.
46 *
47 * Revision 1.2 1999/07/26 23:28:39 mdw
48 * Major reconstruction work for new design.
49 *
50 * Revision 1.1.1.1 1999/07/01 08:56:23 mdw
51 * Initial revision.
52 *
53 */
54
55 #ifndef CONF_H
56 #define CONF_H
57
58 #ifdef __cplusplus
59 extern "C" {
60 #endif
61
62 /*----- Header files ------------------------------------------------------*/
63
64 #include <mLib/dstr.h>
65
66 #ifndef SCAN_H
67 # include "scan.h"
68 #endif
69
70 /*----- Magic numbers -----------------------------------------------------*/
71
72 #define CTOK_EOF (-1)
73 #define CTOK_WORD 256
74
75 /*----- Functions provided ------------------------------------------------*/
76
77 /* --- @conf_undelim@ --- *
78 *
79 * Arguments: @scanner *sc@ = pointer to scanner definition
80 * @const char *d, *dd@ = pointer to characters to escape
81 *
82 * Returns: ---
83 *
84 * Use: Modifies the tokenizer. Characters in the first list will
85 * always be considered to begin a word. Characters in the
86 * second list will always be allowed to continue a word.
87 */
88
89 extern void conf_undelim(scanner */*sc*/,
90 const char */*d*/, const char */*dd*/);
91
92 /* --- @token@ --- *
93 *
94 * Arguments: @scanner *sc@ = pointer to scanner definition
95 *
96 * Returns: Type of token scanned.
97 *
98 * Use: Reads the next token from the character scanner.
99 */
100
101 extern int token(scanner */*sc*/);
102
103 /* --- @error@ --- *
104 *
105 * Arguments: @scanner *sc@ = pointer to scanner definition
106 * @const char *msg@ = message skeleton string
107 * @...@ = extra arguments for the skeleton
108 *
109 * Returns: Doesn't
110 *
111 * Use: Reports an error at the current scanner location.
112 */
113
114 extern void error(scanner */*sc*/, const char */*msg*/, ...);
115
116 /* --- @conf_enum@ --- *
117 *
118 * Arguments: @scanner *sc@ = pointer to a scanner object
119 * @const char *list@ = comma-separated things to allow
120 * @unsigned @f = flags for the search
121 * @const char *err@ = error message if not found
122 *
123 * Returns: Index into list, zero-based, or @-1@.
124 *
125 * Use: Checks whether the current token is a string which matches
126 * one of the comma-separated items given. The return value is
127 * the index (zero-based) of the matched string in the list.
128 *
129 * The flags control the behaviour if no exact match is found.
130 * If @ENUM_ABBREV@ is set, and the current token is a left
131 * substring of exactly one of the possibilities, then that one
132 * is chosen. If @ENUM_NONE@ is set, the value @-1@ is
133 * returned; otherwise an error is reported and the program is
134 * terminated.
135 */
136
137 #define ENUM_ABBREV 1u
138 #define ENUM_NONE 2u
139
140 extern int conf_enum(scanner */*sc*/, const char */*list*/,
141 unsigned /*flags*/, const char */*err*/);
142
143 /* --- @conf_prefix@ --- *
144 *
145 * Arguments: @scanner *sc@ = pointer to a scanner object
146 * @const char *p@ = pointer to prefix string to check
147 *
148 * Returns: Nonzero if the prefix matches.
149 *
150 * Use: If the current token is a word matching the given prefix
151 * string, then it and an optional `.' character are removed and
152 * a nonzero result is returned. Otherwise the current token is
153 * left as it is, and zero is returned.
154 *
155 * Typical options parsing code would remove an expected prefix,
156 * scan an option anyway (since qualifying prefixes are
157 * optional) and if a match is found, claim the option. If no
158 * match is found, and a prefix was stripped, then an error
159 * should be reported.
160 */
161
162 extern int conf_prefix(scanner */*sc*/, const char */*p*/);
163
164 /* --- @CONF_BEGIN@, @CONF_END@ --- *
165 *
166 * Arguments: @sc@ = scanner to read from
167 * @prefix@ = prefix to scan for
168 * @desc@ = description of what we're parsing
169 *
170 * Use: Bracket an options parsing routine. The current token is
171 * checked to see whether it matches the prefix. If so, it is
172 * removed and the following token examined. If that's a `.'
173 * then it's removed. If it's a `{' then the enclosed
174 * option-parsing code is executed in a loop until a matching
175 * '}' is found. If the options parser doesn't accept an
176 * option, the behaviour is dependent on whether a prefix was
177 * seen: if so, an error is reported; otherwse a zero return is
178 * made.
179 */
180
181 #define CS_PLAIN 0
182 #define CS_PREFIX 1
183 #define CS_BRACE 2
184 #define CS_UNKNOWN 3
185
186 #define CONF_BEGIN(sc, prefix, desc) do { \
187 scanner *_conf_sc = (sc); \
188 const char *_conf_desc = (desc); \
189 int _conf_state = CS_PLAIN; \
190 \
191 /* --- Read the initial prefix --- */ \
192 \
193 if (_conf_sc->t == CTOK_WORD && \
194 strcmp(_conf_sc->d.buf, (prefix)) == 0) { \
195 token(_conf_sc); \
196 _conf_state = CS_PREFIX; \
197 if (_conf_sc->t == '.') \
198 token(_conf_sc); \
199 else if (_conf_sc->t == '{') { \
200 token(_conf_sc); \
201 _conf_state = CS_BRACE; \
202 } \
203 } \
204 \
205 /* --- Ensure the next token is a word --- */ \
206 \
207 if (_conf_sc->t != CTOK_WORD) \
208 error(_conf_sc, "parse error, expected option keyword"); \
209 do {
210
211 #define CONF_END \
212 \
213 /* --- Reject an option --- * \
214 * \
215 * We could get here as a result of an explicit @CONF_REJECT@ or \
216 * because the option wasn't accepted. \
217 */ \
218 \
219 goto _conf_reject; \
220 _conf_reject: \
221 if (_conf_state == CS_PLAIN) \
222 _conf_state = CS_UNKNOWN; \
223 else { \
224 error(_conf_sc, "unknown %s option `%s'", \
225 _conf_desc, _conf_sc->d.buf); \
226 } \
227 \
228 /* --- Accept an option --- * \
229 * \
230 * It's safe to drop through from above. Either an error will have \
231 * been reported, or the state is not @CS_BRACE@. \
232 */ \
233 \
234 _conf_accept: \
235 if (_conf_state == CS_BRACE && _conf_sc->t == ';') \
236 token(_conf_sc); \
237 } while (_conf_state == CS_BRACE && _conf_sc->t == CTOK_WORD); \
238 \
239 /* --- Check for a closing brace --- */ \
240 \
241 if (_conf_state == CS_BRACE) { \
242 if (_conf_sc->t == '}') \
243 token(_conf_sc); \
244 else \
245 error(_conf_sc, "parse error, expected `}'"); \
246 } \
247 \
248 /* --- Return an appropriate value --- */ \
249 \
250 return (_conf_state != CS_UNKNOWN); \
251 } while (0)
252
253 /* --- @CONF_ACCEPT@, @CONF_REJECT@ --- *
254 *
255 * Arguments: ---
256 *
257 * Use: Within an options parser (between @CONF_BEGIN@ and
258 * @CONF_END@), accept or reject an option.
259 */
260
261 #define CONF_ACCEPT goto _conf_accept
262 #define CONF_REJECT goto _conf_reject
263
264 /* --- @CONF_QUAL@ --- *
265 *
266 * Arguments: ---
267 *
268 * Use: Evaluates to a nonzero value if the current option is
269 * qualified. This can be used to decide whether abbreviations
270 * for options should be accepted.
271 */
272
273 #define CONF_QUAL (_conf_state != CS_PLAIN)
274
275 /* --- @conf_name@ --- *
276 *
277 * Arguments: @scanner *sc@ = pointer to scanner
278 * @char delim@ = delimiter character to look for
279 * @dstr *d@ = pointer to dynamic string for output
280 *
281 * Returns: ---
282 *
283 * Use: Reads in a compound name consisting of words separated by
284 * delimiters. Leading and trailing delimiters are permitted,
285 * although they'll probably cause confusion if used. The name
286 * may be enclosed in square brackets if that helps at all.
287 *
288 * Examples of compound names are filenames (delimited by `/')
289 * and IP addresses (delimited by `.').
290 */
291
292 extern void conf_name(scanner */*sc*/, char /*delim*/, dstr */*d*/);
293
294 /* --- @conf_parse@ --- *
295 *
296 * Arguments: @scanner *sc@ = pointer to a scanner structure
297 *
298 * Returns: ---
299 *
300 * Use: Parses a configuration file fragment from the scanner
301 */
302
303 extern void conf_parse(scanner *sc);
304
305 /*----- That's all, folks -------------------------------------------------*/
306
307 #ifdef __cplusplus
308 }
309 #endif
310
311 #endif
Port forwarder with too many features