[fwd] / conf.h

/* -*-c-*-
 *
 * $Id: conf.h,v 1.5 1999/10/22 22:46:44 mdw Exp $
 *
 * Configuration parsing
 *
 * (c) 1999 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of the `fw' port forwarder.
 *
 * `fw' is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * `fw' is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with `fw'; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: conf.h,v $
 * Revision 1.5  1999/10/22 22:46:44  mdw
 * Improve documentation for conf_enum.
 *
 * Revision 1.4  1999/08/19 18:32:48  mdw
 * Improve lexical analysis.  In particular, `chmod' patterns don't have to
 * be quoted any more.
 *
 * Revision 1.3  1999/07/27 18:30:14  mdw
 * Improve documentation and layout for @CONF_BEGIN@ and friends.  Remove
 * irritating warning about unused label by introducing a spurious `goto'.
 *
 * Revision 1.2  1999/07/26 23:28:39  mdw
 * Major reconstruction work for new design.
 *
 * Revision 1.1.1.1  1999/07/01 08:56:23  mdw
 * Initial revision.
 *
 */

#ifndef CONF_H
#define CONF_H

#ifdef __cplusplus
  extern "C" {
#endif

/*----- Header files ------------------------------------------------------*/

#include <mLib/dstr.h>

#ifndef SCAN_H
#  include "scan.h"
#endif

/*----- Magic numbers -----------------------------------------------------*/

#define CTOK_EOF (-1)
#define CTOK_WORD 256

/*----- Functions provided ------------------------------------------------*/

/* --- @undelim@ --- *
 *
 * Arguments:	@const char *d, dd@ = pointer to characters to escape
 *
 * Returns:	---
 *
 * Use:		Modifies the tokenizer.  Characters in the first list will
 *		always be considered to begin a word.  Characters in the
 *		second list will always be allowed to continue a word.
 */

extern void undelim(const char */*d*/, const char */*dd*/);

/* --- @token@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to scanner definition
 *
 * Returns:	Type of token scanned.
 *
 * Use:		Reads the next token from the character scanner.
 */

extern int token(scanner */*sc*/);

/* --- @error@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to scanner definition
 *		@const char *msg@ = message skeleton string
 *		@...@ = extra arguments for the skeleton
 *
 * Returns:	Doesn't
 *
 * Use:		Reports an error at the current scanner location.
 */

extern void error(scanner */*sc*/, const char */*msg*/, ...);

/* --- @conf_enum@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to a scanner object
 *		@const char *list@ = comma-separated things to allow
 *		@unsigned @f = flags for the search
 *		@const char *err@ = error message if not found
 *
 * Returns:	Index into list, zero-based, or @-1@.
 *
 * Use:		Checks whether the current token is a string which matches
 *		one of the comma-separated items given.  The return value is
 *		the index (zero-based) of the matched string in the list.
 *
 *		The flags control the behaviour if no exact match is found.
 *		If @ENUM_ABBREV@ is set, and the current token is a left
 *		substring of exactly one of the possibilities, then that one
 *		is chosen.  If @ENUM_NONE@ is set, the value @-1@ is
 *		returned; otherwise an error is reported and the program is
 *		terminated.
 */

#define ENUM_ABBREV 1u
#define ENUM_NONE 2u

extern int conf_enum(scanner */*sc*/, const char */*list*/,
		     unsigned /*flags*/, const char */*err*/);

/* --- @conf_prefix@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to a scanner object
 *		@const char *p@ = pointer to prefix string to check
 *
 * Returns:	Nonzero if the prefix matches.
 *
 * Use:		If the current token is a word matching the given prefix
 *		string, then it and an optional `.' character are removed and
 *		a nonzero result is returned.  Otherwise the current token is
 *		left as it is, and zero is returned.
 *
 *		Typical options parsing code would remove an expected prefix,
 *		scan an option anyway (since qualifying prefixes are
 *		optional) and if a match is found, claim the option.  If no
 *		match is found, and a prefix was stripped, then an error
 *		should be reported.
 */

extern int conf_prefix(scanner */*sc*/, const char */*p*/);

/* --- @CONF_BEGIN@, @CONF_END@ --- *
 *
 * Arguments:	@sc@ = scanner to read from
 *		@prefix@ = prefix to scan for
 *		@desc@ = description of what we're parsing
 *
 * Use:		Bracket an options parsing routine.  The current token is
 *		checked to see whether it matches the prefix.  If so, it is
 *		removed and the following token examined.  If that's a `.'
 *		then it's removed.  If it's a `{' then the enclosed
 *		option-parsing code is executed in a loop until a matching
 *		'}' is found.  If the options parser doesn't accept an
 *		option, the behaviour is dependent on whether a prefix was
 *		seen: if so, an error is reported; otherwse a zero return is
 *		made.
 */

#define CS_PLAIN 0
#define CS_PREFIX 1
#define CS_BRACE 2
#define CS_UNKNOWN 3

#define CONF_BEGIN(sc, prefix, desc) do {				\
  scanner *_conf_sc = (sc);						\
  const char *_conf_desc = (desc);					\
  int _conf_state = CS_PLAIN;						\
									\
  /* --- Read the initial prefix --- */					\
									\
  if (_conf_sc->t == CTOK_WORD &&					\
      strcmp(_conf_sc->d.buf, (prefix)) == 0) {				\
    token(_conf_sc);							\
    _conf_state = CS_PREFIX;						\
    if (_conf_sc->t == '.')						\
      token(_conf_sc);							\
    else if (_conf_sc->t == '{') {					\
      token(_conf_sc);							\
      _conf_state = CS_BRACE;						\
    }									\
  }									\
									\
  /* --- Ensure the next token is a word --- */				\
									\
  if (_conf_sc->t != CTOK_WORD)						\
    error(_conf_sc, "parse error, expected option keyword");		\
  do {

#define CONF_END							\
									\
    /* --- Reject an option --- *					\
     *									\
     * We could get here as a result of an explicit @CONF_REJECT@ or	\
     * because the option wasn't accepted.				\
     */									\
									\
     goto _conf_reject;							\
  _conf_reject:								\
    if (_conf_state == CS_PLAIN)					\
      _conf_state = CS_UNKNOWN;						\
    else {								\
      error(_conf_sc, "unknown %s option `%s'",				\
	    _conf_desc, _conf_sc->d.buf);				\
    }									\
									\
    /* --- Accept an option --- *					\
     *									\
     * It's safe to drop through from above.  Either an error will have	\
     * been reported, or the state is not @CS_BRACE@.			\
     */									\
									\
  _conf_accept:								\
    if (_conf_state == CS_BRACE && _conf_sc->t == ';')			\
      token(_conf_sc);							\
  } while (_conf_state == CS_BRACE && _conf_sc->t == CTOK_WORD);	\
									\
  /* --- Check for a closing brace --- */				\
									\
  if (_conf_state == CS_BRACE) {					\
    if (_conf_sc->t == '}')						\
      token(_conf_sc);							\
    else								\
      error(_conf_sc, "parse error, expected `}'");			\
  }									\
									\
  /* --- Return an appropriate value --- */				\
									\
  return (_conf_state != CS_UNKNOWN);					\
} while (0)

/* --- @CONF_ACCEPT@, @CONF_REJECT@ --- *
 *
 * Arguments:	---
 *
 * Use:		Within an options parser (between @CONF_BEGIN@ and
 *		@CONF_END@), accept or reject an option.
 */

#define CONF_ACCEPT goto _conf_accept
#define CONF_REJECT goto _conf_reject

/* --- @CONF_QUAL@ --- *
 *
 * Arguments:	---
 *
 * Use:		Evaluates to a nonzero value if the current option is
 *		qualified.  This can be used to decide whether abbreviations
 *		for options should be accepted.
 */

#define CONF_QUAL (_conf_state != CS_PLAIN)

/* --- @conf_name@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to scanner
 *		@char delim@ = delimiter character to look for
 *		@dstr *d@ = pointer to dynamic string for output
 *
 * Returns:	---
 *
 * Use:		Reads in a compound name consisting of words separated by
 *		delimiters.  Leading and trailing delimiters are permitted,
 *		although they'll probably cause confusion if used.  The name
 *		may be enclosed in square brackets if that helps at all.
 *
 *		Examples of compound names are filenames (delimited by `/')
 *		and IP addresses (delimited by `.').
 */

extern void conf_name(scanner */*sc*/, char /*delim*/, dstr */*d*/);

/* --- @conf_parse@ --- *
 *
 * Arguments:	@scanner *sc@ = pointer to a scanner structure
 *
 * Returns:	---
 *
 * Use:		Parses a configuration file fragment from the scanner
 */

extern void conf_parse(scanner *sc);

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif
Commit	Line	Data
e82f7154	1	/* --c--
e82f7154	2	*
82793759	3	* $Id: conf.h,v 1.5 1999/10/22 22:46:44 mdw Exp $
e82f7154	4	*
	5	* Configuration parsing
	6	*
61e3dbdf	7	* (c) 1999 Straylight/Edgeware
e82f7154	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 $
82793759	32	* Revision 1.5 1999/10/22 22:46:44 mdw
	33	* Improve documentation for conf_enum.
	34	*
e73034b0	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	*
022008ac	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	*
61e3dbdf	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.
e82f7154	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
61e3dbdf	60	#include <mLib/dstr.h>
61e3dbdf	61
e82f7154	62	#ifndef SCAN_H
	63	# include "scan.h"
	64	#endif
	65
61e3dbdf	66	/----- Magic numbers -----------------------------------------------------/
	67
	68	#define CTOK_EOF (-1)
	69	#define CTOK_WORD 256
	70
e82f7154	71	/----- Functions provided ------------------------------------------------/
e82f7154	72
e73034b0	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
61e3dbdf	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
82793759	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.
61e3dbdf	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
022008ac	158	/* --- @CONF_BEGIN@, @CONF_END@ --- *
61e3dbdf	159	*
	160	* Arguments: @sc@ = scanner to read from
	161	* @prefix@ = prefix to scan for
	162	* @desc@ = description of what we're parsing
	163	*
022008ac	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.
61e3dbdf	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; \
022008ac	184	\
	185	/* --- Read the initial prefix --- */ \
	186	\
61e3dbdf	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	} \
022008ac	198	\
	199	/* --- Ensure the next token is a word --- */ \
	200	\
61e3dbdf	201	if (_conf_sc->t != CTOK_WORD) \
	202	error(_conf_sc, "parse error, expected option keyword"); \
	203	do {
	204
61e3dbdf	205	#define CONF_END \
022008ac	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; \
61e3dbdf	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	} \
022008ac	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	\
61e3dbdf	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); \
022008ac	232	\
	233	/* --- Check for a closing brace --- */ \
	234	\
61e3dbdf	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	} \
022008ac	241	\
	242	/* --- Return an appropriate value --- */ \
	243	\
61e3dbdf	244	return (_conf_state != CS_UNKNOWN); \
	245	} while (0)
	246
022008ac	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
61e3dbdf	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
e82f7154	288	/* --- @conf_parse@ --- *
e82f7154	289	*
61e3dbdf	290	* Arguments: @scanner *sc@ = pointer to a scanner structure
e82f7154	291	*
	292	* Returns: ---
	293	*
	294	* Use: Parses a configuration file fragment from the scanner
	295	*/
	296
61e3dbdf	297	extern void conf_parse(scanner *sc);
e82f7154	298
	299	/----- That's all, folks -------------------------------------------------/
	300
	301	#ifdef __cplusplus
	302	}
	303	#endif
	304
	305	#endif