3 * $Id: conf.h,v 1.7 2002/02/22 23:42:56 mdw Exp $
5 * Configuration parsing
7 * (c) 1999 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the `fw' port forwarder.
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.
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.
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.
29 /*----- Revision history --------------------------------------------------*
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.
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.
40 * Revision 1.5 1999/10/22 22:46:44 mdw
41 * Improve documentation for conf_enum.
43 * Revision 1.4 1999/08/19 18:32:48 mdw
44 * Improve lexical analysis. In particular, `chmod' patterns don't have to
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'.
51 * Revision 1.2 1999/07/26 23:28:39 mdw
52 * Major reconstruction work for new design.
54 * Revision 1.1.1.1 1999/07/01 08:56:23 mdw
66 /*----- Header files ------------------------------------------------------*/
68 #include <mLib/dstr.h>
74 /*----- Magic numbers -----------------------------------------------------*/
79 /*----- Functions provided ------------------------------------------------*/
81 /* --- @conf_undelim@ --- *
83 * Arguments: @scanner *sc@ = pointer to scanner definition
84 * @const char *d, *dd@ = pointer to characters to escape
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.
93 extern void conf_undelim(scanner */
*sc*/
,
94 const char */
*d*/
, const char */
*dd*/
);
98 * Arguments: @scanner *sc@ = pointer to scanner definition
100 * Returns: Type of token scanned.
102 * Use: Reads the next token from the character scanner.
105 extern int token(scanner */
*sc*/
);
109 * Arguments: @scanner *sc@ = pointer to scanner definition
110 * @const char *msg@ = message skeleton string
111 * @...@ = extra arguments for the skeleton
115 * Use: Reports an error at the current scanner location.
118 extern void error(scanner */
*sc*/
, const char */
*msg*/
, ...);
120 /* --- @pushback@ --- *
122 * Arguments: @scanner *sc@ = pointer to scanner definition
126 * Use: Pushes the current token back. This is normally a precursor
127 * to pushing a new scanner source.
130 extern void pushback(scanner */
*sc*/
);
132 /* --- @conf_enum@ --- *
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
139 * Returns: Index into list, zero-based, or @-1@.
141 * Use: Checks whether the current token is a string which matches
142 * one of the comma-separated items given. The return value is
143 * the index (zero-based) of the matched string in the list.
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
153 #define ENUM_ABBREV 1u
156 extern int conf_enum(scanner */
*sc*/
, const char */
*list*/
,
157 unsigned /*flags*/, const char */
*err*/
);
159 /* --- @conf_prefix@ --- *
161 * Arguments: @scanner *sc@ = pointer to a scanner object
162 * @const char *p@ = pointer to prefix string to check
164 * Returns: Nonzero if the prefix matches.
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.
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.
178 extern int conf_prefix(scanner */
*sc*/
, const char */
*p*/
);
180 /* --- @CONF_BEGIN@, @CONF_END@ --- *
182 * Arguments: @sc@ = scanner to read from
183 * @prefix@ = prefix to scan for
184 * @desc@ = description of what we're parsing
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
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; \
207 /* --- Read the initial prefix --- */ \
209 if (_conf_sc->t == CTOK_WORD && \
210 strcmp(_conf_sc->d.buf, (prefix)) == 0) { \
212 _conf_state = CS_PREFIX; \
213 if (_conf_sc->t == '.') \
215 else if (_conf_sc->t == '{') { \
217 _conf_state = CS_BRACE; \
221 /* --- Ensure the next token is a word --- */ \
223 if (_conf_sc->t != CTOK_WORD) \
224 error(_conf_sc, "parse error, expected option keyword"); \
229 /* --- Reject an option --- * \
231 * We could get here as a result of an explicit @CONF_REJECT@ or \
232 * because the option wasn't accepted. \
237 if (_conf_state == CS_PLAIN) \
238 _conf_state = CS_UNKNOWN; \
240 error(_conf_sc, "unknown %s option `%s'", \
241 _conf_desc, _conf_sc->d.buf); \
244 /* --- Accept an option --- * \
246 * It's safe to drop through from above. Either an error will have \
247 * been reported, or the state is not @CS_BRACE@. \
251 if (_conf_state == CS_BRACE && _conf_sc->t == ';') \
253 } while (_conf_state == CS_BRACE && _conf_sc->t == CTOK_WORD); \
255 /* --- Check for a closing brace --- */ \
257 if (_conf_state == CS_BRACE) { \
258 if (_conf_sc->t == '}') \
261 error(_conf_sc, "parse error, expected `}'"); \
264 /* --- Return an appropriate value --- */ \
266 return (_conf_state != CS_UNKNOWN); \
269 /* --- @CONF_ACCEPT@, @CONF_REJECT@ --- *
273 * Use: Within an options parser (between @CONF_BEGIN@ and
274 * @CONF_END@), accept or reject an option.
277 #define CONF_ACCEPT goto _conf_accept
278 #define CONF_REJECT goto _conf_reject
280 /* --- @CONF_QUAL@ --- *
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.
289 #define CONF_QUAL (_conf_state != CS_PLAIN)
291 /* --- @conf_name@ --- *
293 * Arguments: @scanner *sc@ = pointer to scanner
294 * @char delim@ = delimiter character to look for
295 * @dstr *d@ = pointer to dynamic string for output
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.
304 * Examples of compound names are filenames (delimited by `/')
305 * and IP addresses (delimited by `.').
308 extern void conf_name(scanner */
*sc*/
, char /*delim*/, dstr */
*d*/
);
310 /*----- That's all, folks -------------------------------------------------*/