| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Configuration parsing |
| 4 | * |
| 5 | * (c) 1999 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of the `fw' port forwarder. |
| 11 | * |
| 12 | * `fw' is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU General Public License as published by |
| 14 | * the Free Software Foundation; either version 2 of the License, or |
| 15 | * (at your option) any later version. |
| 16 | * |
| 17 | * `fw' is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU General Public License |
| 23 | * along with `fw'; if not, write to the Free Software Foundation, |
| 24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 25 | */ |
| 26 | |
| 27 | #ifndef CONF_H |
| 28 | #define CONF_H |
| 29 | |
| 30 | #ifdef __cplusplus |
| 31 | extern "C" { |
| 32 | #endif |
| 33 | |
| 34 | /*----- Header files ------------------------------------------------------*/ |
| 35 | |
| 36 | #include <mLib/dstr.h> |
| 37 | |
| 38 | #ifndef SCAN_H |
| 39 | # include "scan.h" |
| 40 | #endif |
| 41 | |
| 42 | /*----- Magic numbers -----------------------------------------------------*/ |
| 43 | |
| 44 | #define CTOK_EOF (-1) |
| 45 | #define CTOK_WORD 256 |
| 46 | |
| 47 | /*----- Functions provided ------------------------------------------------*/ |
| 48 | |
| 49 | /* --- @conf_undelim@ --- * |
| 50 | * |
| 51 | * Arguments: @scanner *sc@ = pointer to scanner definition |
| 52 | * @const char *d, *dd@ = pointer to characters to escape |
| 53 | * |
| 54 | * Returns: --- |
| 55 | * |
| 56 | * Use: Modifies the tokenizer. Characters in the first list will |
| 57 | * always be considered to begin a word. Characters in the |
| 58 | * second list will always be allowed to continue a word. |
| 59 | */ |
| 60 | |
| 61 | extern void conf_undelim(scanner */*sc*/, |
| 62 | const char */*d*/, const char */*dd*/); |
| 63 | |
| 64 | /* --- @token@ --- * |
| 65 | * |
| 66 | * Arguments: @scanner *sc@ = pointer to scanner definition |
| 67 | * |
| 68 | * Returns: Type of token scanned. |
| 69 | * |
| 70 | * Use: Reads the next token from the character scanner. |
| 71 | */ |
| 72 | |
| 73 | extern int token(scanner */*sc*/); |
| 74 | |
| 75 | /* --- @error@ --- * |
| 76 | * |
| 77 | * Arguments: @scanner *sc@ = pointer to scanner definition |
| 78 | * @const char *msg@ = message skeleton string |
| 79 | * @...@ = extra arguments for the skeleton |
| 80 | * |
| 81 | * Returns: Doesn't |
| 82 | * |
| 83 | * Use: Reports an error at the current scanner location. |
| 84 | */ |
| 85 | |
| 86 | extern void error(scanner */*sc*/, const char */*msg*/, ...); |
| 87 | |
| 88 | /* --- @pushback@ --- * |
| 89 | * |
| 90 | * Arguments: @scanner *sc@ = pointer to scanner definition |
| 91 | * |
| 92 | * Returns: --- |
| 93 | * |
| 94 | * Use: Pushes the current token back. This is normally a precursor |
| 95 | * to pushing a new scanner source. |
| 96 | */ |
| 97 | |
| 98 | extern void pushback(scanner */*sc*/); |
| 99 | |
| 100 | /* --- @conf_enum@ --- * |
| 101 | * |
| 102 | * Arguments: @scanner *sc@ = pointer to a scanner object |
| 103 | * @const char *list@ = comma-separated things to allow |
| 104 | * @unsigned @f = flags for the search |
| 105 | * @const char *err@ = error message if not found |
| 106 | * |
| 107 | * Returns: Index into list, zero-based, or @-1@. |
| 108 | * |
| 109 | * Use: Checks whether the current token is a string which matches |
| 110 | * one of the comma-separated items given. The return value is |
| 111 | * the index (zero-based) of the matched string in the list. |
| 112 | * |
| 113 | * The flags control the behaviour if no exact match is found. |
| 114 | * If @ENUM_ABBREV@ is set, and the current token is a left |
| 115 | * substring of exactly one of the possibilities, then that one |
| 116 | * is chosen. If @ENUM_NONE@ is set, the value @-1@ is |
| 117 | * returned; otherwise an error is reported and the program is |
| 118 | * terminated. |
| 119 | */ |
| 120 | |
| 121 | #define ENUM_ABBREV 1u |
| 122 | #define ENUM_NONE 2u |
| 123 | |
| 124 | extern int conf_enum(scanner */*sc*/, const char */*list*/, |
| 125 | unsigned /*flags*/, const char */*err*/); |
| 126 | |
| 127 | /* --- @conf_prefix@ --- * |
| 128 | * |
| 129 | * Arguments: @scanner *sc@ = pointer to a scanner object |
| 130 | * @const char *p@ = pointer to prefix string to check |
| 131 | * |
| 132 | * Returns: Nonzero if the prefix matches. |
| 133 | * |
| 134 | * Use: If the current token is a word matching the given prefix |
| 135 | * string, then it and an optional `.' character are removed and |
| 136 | * a nonzero result is returned. Otherwise the current token is |
| 137 | * left as it is, and zero is returned. |
| 138 | * |
| 139 | * Typical options parsing code would remove an expected prefix, |
| 140 | * scan an option anyway (since qualifying prefixes are |
| 141 | * optional) and if a match is found, claim the option. If no |
| 142 | * match is found, and a prefix was stripped, then an error |
| 143 | * should be reported. |
| 144 | */ |
| 145 | |
| 146 | extern int conf_prefix(scanner */*sc*/, const char */*p*/); |
| 147 | |
| 148 | /* --- @CONF_BEGIN@, @CONF_END@ --- * |
| 149 | * |
| 150 | * Arguments: @sc@ = scanner to read from |
| 151 | * @prefix@ = prefix to scan for |
| 152 | * @desc@ = description of what we're parsing |
| 153 | * |
| 154 | * Use: Bracket an options parsing routine. The current token is |
| 155 | * checked to see whether it matches the prefix. If so, it is |
| 156 | * removed and the following token examined. If that's a `.' |
| 157 | * then it's removed. If it's a `{' then the enclosed |
| 158 | * option-parsing code is executed in a loop until a matching |
| 159 | * '}' is found. If the options parser doesn't accept an |
| 160 | * option, the behaviour is dependent on whether a prefix was |
| 161 | * seen: if so, an error is reported; otherwse a zero return is |
| 162 | * made. |
| 163 | */ |
| 164 | |
| 165 | #define CS_PLAIN 0 |
| 166 | #define CS_PREFIX 1 |
| 167 | #define CS_BRACE 2 |
| 168 | #define CS_UNKNOWN 3 |
| 169 | |
| 170 | #define CONF_BEGIN(sc, prefix, desc) do { \ |
| 171 | scanner *_conf_sc = (sc); \ |
| 172 | const char *_conf_desc = (desc); \ |
| 173 | int _conf_state = CS_PLAIN; \ |
| 174 | \ |
| 175 | /* --- Read the initial prefix --- */ \ |
| 176 | \ |
| 177 | if (_conf_sc->t == CTOK_WORD && \ |
| 178 | strcmp(_conf_sc->d.buf, (prefix)) == 0) { \ |
| 179 | token(_conf_sc); \ |
| 180 | _conf_state = CS_PREFIX; \ |
| 181 | if (_conf_sc->t == '.') \ |
| 182 | token(_conf_sc); \ |
| 183 | else if (_conf_sc->t == '{') { \ |
| 184 | token(_conf_sc); \ |
| 185 | _conf_state = CS_BRACE; \ |
| 186 | } \ |
| 187 | } \ |
| 188 | \ |
| 189 | /* --- Ensure the next token is a word --- */ \ |
| 190 | \ |
| 191 | if (_conf_sc->t != CTOK_WORD) \ |
| 192 | error(_conf_sc, "parse error, expected option keyword"); \ |
| 193 | do { |
| 194 | |
| 195 | #define CONF_END \ |
| 196 | \ |
| 197 | /* --- Reject an option --- * \ |
| 198 | * \ |
| 199 | * We could get here as a result of an explicit @CONF_REJECT@ or \ |
| 200 | * because the option wasn't accepted. \ |
| 201 | */ \ |
| 202 | \ |
| 203 | goto _conf_reject; \ |
| 204 | _conf_reject: \ |
| 205 | if (_conf_state == CS_PLAIN) \ |
| 206 | _conf_state = CS_UNKNOWN; \ |
| 207 | else { \ |
| 208 | error(_conf_sc, "unknown %s option `%s'", \ |
| 209 | _conf_desc, _conf_sc->d.buf); \ |
| 210 | } \ |
| 211 | \ |
| 212 | /* --- Accept an option --- * \ |
| 213 | * \ |
| 214 | * It's safe to drop through from above. Either an error will have \ |
| 215 | * been reported, or the state is not @CS_BRACE@. \ |
| 216 | */ \ |
| 217 | \ |
| 218 | _conf_accept: \ |
| 219 | if (_conf_state == CS_BRACE && _conf_sc->t == ';') \ |
| 220 | token(_conf_sc); \ |
| 221 | } while (_conf_state == CS_BRACE && _conf_sc->t == CTOK_WORD); \ |
| 222 | \ |
| 223 | /* --- Check for a closing brace --- */ \ |
| 224 | \ |
| 225 | if (_conf_state == CS_BRACE) { \ |
| 226 | if (_conf_sc->t == '}') \ |
| 227 | token(_conf_sc); \ |
| 228 | else \ |
| 229 | error(_conf_sc, "parse error, expected `}'"); \ |
| 230 | } \ |
| 231 | \ |
| 232 | /* --- Return an appropriate value --- */ \ |
| 233 | \ |
| 234 | return (_conf_state != CS_UNKNOWN); \ |
| 235 | } while (0) |
| 236 | |
| 237 | /* --- @CONF_ACCEPT@, @CONF_REJECT@ --- * |
| 238 | * |
| 239 | * Arguments: --- |
| 240 | * |
| 241 | * Use: Within an options parser (between @CONF_BEGIN@ and |
| 242 | * @CONF_END@), accept or reject an option. |
| 243 | */ |
| 244 | |
| 245 | #define CONF_ACCEPT goto _conf_accept |
| 246 | #define CONF_REJECT goto _conf_reject |
| 247 | |
| 248 | /* --- @CONF_QUAL@ --- * |
| 249 | * |
| 250 | * Arguments: --- |
| 251 | * |
| 252 | * Use: Evaluates to a nonzero value if the current option is |
| 253 | * qualified. This can be used to decide whether abbreviations |
| 254 | * for options should be accepted. |
| 255 | */ |
| 256 | |
| 257 | #define CONF_QUAL (_conf_state != CS_PLAIN) |
| 258 | |
| 259 | /* --- @conf_name@ --- * |
| 260 | * |
| 261 | * Arguments: @scanner *sc@ = pointer to scanner |
| 262 | * @char delim@ = delimiter character to look for |
| 263 | * @dstr *d@ = pointer to dynamic string for output |
| 264 | * |
| 265 | * Returns: --- |
| 266 | * |
| 267 | * Use: Reads in a compound name consisting of words separated by |
| 268 | * delimiters. Leading and trailing delimiters are permitted, |
| 269 | * although they'll probably cause confusion if used. The name |
| 270 | * may be enclosed in square brackets if that helps at all. |
| 271 | * |
| 272 | * Examples of compound names are filenames (delimited by `/') |
| 273 | * and IP addresses (delimited by `.'). |
| 274 | */ |
| 275 | |
| 276 | extern void conf_name(scanner */*sc*/, char /*delim*/, dstr */*d*/); |
| 277 | |
| 278 | /*----- That's all, folks -------------------------------------------------*/ |
| 279 | |
| 280 | #ifdef __cplusplus |
| 281 | } |
| 282 | #endif |
| 283 | |
| 284 | #endif |