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Minor fixings to wording.
[fwd] / conf.h
1 /* -*-c-*-
2 *
3 * $Id: conf.h,v 1.5 1999/10/22 22:46:44 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 1.5 1999/10/22 22:46:44 mdw
33 * Improve documentation for conf_enum.
34 *
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 *
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 *
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.
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
60 #include <mLib/dstr.h>
61
62 #ifndef SCAN_H
63 # include "scan.h"
64 #endif
65
66 /*----- Magic numbers -----------------------------------------------------*/
67
68 #define CTOK_EOF (-1)
69 #define CTOK_WORD 256
70
71 /*----- Functions provided ------------------------------------------------*/
72
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
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
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.
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
158 /* --- @CONF_BEGIN@, @CONF_END@ --- *
159 *
160 * Arguments: @sc@ = scanner to read from
161 * @prefix@ = prefix to scan for
162 * @desc@ = description of what we're parsing
163 *
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.
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; \
184 \
185 /* --- Read the initial prefix --- */ \
186 \
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 } \
198 \
199 /* --- Ensure the next token is a word --- */ \
200 \
201 if (_conf_sc->t != CTOK_WORD) \
202 error(_conf_sc, "parse error, expected option keyword"); \
203 do {
204
205 #define CONF_END \
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; \
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 } \
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 \
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); \
232 \
233 /* --- Check for a closing brace --- */ \
234 \
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 } \
241 \
242 /* --- Return an appropriate value --- */ \
243 \
244 return (_conf_state != CS_UNKNOWN); \
245 } while (0)
246
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
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
288 /* --- @conf_parse@ --- *
289 *
290 * Arguments: @scanner *sc@ = pointer to a scanner structure
291 *
292 * Returns: ---
293 *
294 * Use: Parses a configuration file fragment from the scanner
295 */
296
297 extern void conf_parse(scanner *sc);
298
299 /*----- That's all, folks -------------------------------------------------*/
300
301 #ifdef __cplusplus
302 }
303 #endif
304
305 #endif
Port forwarder with too many features