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1 | /* |
2 | This modules is based on the params.c module from Samba, written by Karl Auer | |
3 | and much modifed by Christopher Hertel. | |
4 | ||
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
18 | * | |
19 | * -------------------------------------------------------------------------- ** | |
20 | * | |
21 | * Module name: params | |
22 | * | |
23 | * -------------------------------------------------------------------------- ** | |
24 | * | |
25 | * This module performs lexical analysis and initial parsing of a | |
26 | * Windows-like parameter file. It recognizes and handles four token | |
27 | * types: section-name, parameter-name, parameter-value, and | |
28 | * end-of-file. Comments and line continuation are handled | |
29 | * internally. | |
30 | * | |
31 | * The entry point to the module is function pm_process(). This | |
32 | * function opens the source file, calls the Parse() function to parse | |
33 | * the input, and then closes the file when either the EOF is reached | |
34 | * or a fatal error is encountered. | |
35 | * | |
36 | * A sample parameter file might look like this: | |
37 | * | |
38 | * [section one] | |
39 | * parameter one = value string | |
40 | * parameter two = another value | |
41 | * [section two] | |
42 | * new parameter = some value or t'other | |
43 | * | |
44 | * The parameter file is divided into sections by section headers: | |
45 | * section names enclosed in square brackets (eg. [section one]). | |
46 | * Each section contains parameter lines, each of which consist of a | |
47 | * parameter name and value delimited by an equal sign. Roughly, the | |
48 | * syntax is: | |
49 | * | |
50 | * <file> :== { <section> } EOF | |
51 | * | |
52 | * <section> :== <section header> { <parameter line> } | |
53 | * | |
54 | * <section header> :== '[' NAME ']' | |
55 | * | |
56 | * <parameter line> :== NAME '=' VALUE '\n' | |
57 | * | |
58 | * Blank lines and comment lines are ignored. Comment lines are lines | |
59 | * beginning with either a semicolon (';') or a pound sign ('#'). | |
60 | * | |
61 | * All whitespace in section names and parameter names is compressed | |
62 | * to single spaces. Leading and trailing whitespace is stipped from | |
63 | * both names and values. | |
64 | * | |
65 | * Only the first equals sign in a parameter line is significant. | |
66 | * Parameter values may contain equals signs, square brackets and | |
67 | * semicolons. Internal whitespace is retained in parameter values, | |
68 | * with the exception of the '\r' character, which is stripped for | |
69 | * historic reasons. Parameter names may not start with a left square | |
70 | * bracket, an equal sign, a pound sign, or a semicolon, because these | |
71 | * are used to identify other tokens. | |
72 | * | |
73 | * -------------------------------------------------------------------------- ** | |
74 | */ | |
75 | ||
76 | #include "rsync.h" | |
77 | #define BOOL int | |
78 | #define False 0 | |
79 | #define True 1 | |
80 | #define Realloc realloc | |
81 | ||
82 | /* -------------------------------------------------------------------------- ** | |
83 | * Constants... | |
84 | */ | |
85 | ||
86 | #define BUFR_INC 1024 | |
87 | ||
88 | ||
89 | /* -------------------------------------------------------------------------- ** | |
90 | * Variables... | |
91 | * | |
92 | * bufr - pointer to a global buffer. This is probably a kludge, | |
93 | * but it was the nicest kludge I could think of (for now). | |
94 | * bSize - The size of the global buffer <bufr>. | |
95 | */ | |
96 | ||
97 | static char *bufr = NULL; | |
98 | static int bSize = 0; | |
99 | ||
100 | /* -------------------------------------------------------------------------- ** | |
101 | * Functions... | |
102 | */ | |
103 | ||
104 | static int EatWhitespace( FILE *InFile ) | |
105 | /* ------------------------------------------------------------------------ ** | |
106 | * Scan past whitespace (see ctype(3C)) and return the first non-whitespace | |
107 | * character, or newline, or EOF. | |
108 | * | |
109 | * Input: InFile - Input source. | |
110 | * | |
111 | * Output: The next non-whitespace character in the input stream. | |
112 | * | |
113 | * Notes: Because the config files use a line-oriented grammar, we | |
114 | * explicitly exclude the newline character from the list of | |
115 | * whitespace characters. | |
116 | * - Note that both EOF (-1) and the nul character ('\0') are | |
117 | * considered end-of-file markers. | |
118 | * | |
119 | * ------------------------------------------------------------------------ ** | |
120 | */ | |
121 | { | |
122 | int c; | |
123 | ||
124 | for( c = getc( InFile ); isspace( c ) && ('\n' != c); c = getc( InFile ) ) | |
125 | ; | |
126 | return( c ); | |
127 | } /* EatWhitespace */ | |
128 | ||
129 | static int EatComment( FILE *InFile ) | |
130 | /* ------------------------------------------------------------------------ ** | |
131 | * Scan to the end of a comment. | |
132 | * | |
133 | * Input: InFile - Input source. | |
134 | * | |
135 | * Output: The character that marks the end of the comment. Normally, | |
136 | * this will be a newline, but it *might* be an EOF. | |
137 | * | |
138 | * Notes: Because the config files use a line-oriented grammar, we | |
139 | * explicitly exclude the newline character from the list of | |
140 | * whitespace characters. | |
141 | * - Note that both EOF (-1) and the nul character ('\0') are | |
142 | * considered end-of-file markers. | |
143 | * | |
144 | * ------------------------------------------------------------------------ ** | |
145 | */ | |
146 | { | |
147 | int c; | |
148 | ||
149 | for( c = getc( InFile ); ('\n'!=c) && (EOF!=c) && (c>0); c = getc( InFile ) ) | |
150 | ; | |
151 | return( c ); | |
152 | } /* EatComment */ | |
153 | ||
154 | static int Continuation( char *line, int pos ) | |
155 | /* ------------------------------------------------------------------------ ** | |
156 | * Scan backards within a string to discover if the last non-whitespace | |
157 | * character is a line-continuation character ('\\'). | |
158 | * | |
159 | * Input: line - A pointer to a buffer containing the string to be | |
160 | * scanned. | |
161 | * pos - This is taken to be the offset of the end of the | |
162 | * string. This position is *not* scanned. | |
163 | * | |
164 | * Output: The offset of the '\\' character if it was found, or -1 to | |
165 | * indicate that it was not. | |
166 | * | |
167 | * ------------------------------------------------------------------------ ** | |
168 | */ | |
169 | { | |
170 | pos--; | |
171 | while( (pos >= 0) && isspace(line[pos]) ) | |
172 | pos--; | |
173 | ||
174 | return( ((pos >= 0) && ('\\' == line[pos])) ? pos : -1 ); | |
175 | } /* Continuation */ | |
176 | ||
177 | ||
178 | static BOOL Section( FILE *InFile, BOOL (*sfunc)(char *) ) | |
179 | /* ------------------------------------------------------------------------ ** | |
180 | * Scan a section name, and pass the name to function sfunc(). | |
181 | * | |
182 | * Input: InFile - Input source. | |
183 | * sfunc - Pointer to the function to be called if the section | |
184 | * name is successfully read. | |
185 | * | |
186 | * Output: True if the section name was read and True was returned from | |
187 | * <sfunc>. False if <sfunc> failed or if a lexical error was | |
188 | * encountered. | |
189 | * | |
190 | * ------------------------------------------------------------------------ ** | |
191 | */ | |
192 | { | |
193 | int c; | |
194 | int i; | |
195 | int end; | |
196 | char *func = "params.c:Section() -"; | |
197 | ||
198 | i = 0; /* <i> is the offset of the next free byte in bufr[] and */ | |
199 | end = 0; /* <end> is the current "end of string" offset. In most */ | |
200 | /* cases these will be the same, but if the last */ | |
201 | /* character written to bufr[] is a space, then <end> */ | |
202 | /* will be one less than <i>. */ | |
203 | ||
204 | c = EatWhitespace( InFile ); /* We've already got the '['. Scan */ | |
205 | /* past initial white space. */ | |
206 | ||
207 | while( (EOF != c) && (c > 0) ) | |
208 | { | |
209 | ||
210 | /* Check that the buffer is big enough for the next character. */ | |
211 | if( i > (bSize - 2) ) | |
212 | { | |
213 | bSize += BUFR_INC; | |
214 | bufr = Realloc( bufr, bSize ); | |
215 | if( NULL == bufr ) | |
216 | { | |
217 | rprintf(FERROR, "%s Memory re-allocation failure.", func); | |
218 | return( False ); | |
219 | } | |
220 | } | |
221 | ||
222 | /* Handle a single character. */ | |
223 | switch( c ) | |
224 | { | |
225 | case ']': /* Found the closing bracket. */ | |
226 | bufr[end] = '\0'; | |
227 | if( 0 == end ) /* Don't allow an empty name. */ | |
228 | { | |
229 | rprintf(FERROR, "%s Empty section name in configuration file.\n", func ); | |
230 | return( False ); | |
231 | } | |
232 | if( !sfunc( bufr ) ) /* Got a valid name. Deal with it. */ | |
233 | return( False ); | |
234 | (void)EatComment( InFile ); /* Finish off the line. */ | |
235 | return( True ); | |
236 | ||
237 | case '\n': /* Got newline before closing ']'. */ | |
238 | i = Continuation( bufr, i ); /* Check for line continuation. */ | |
239 | if( i < 0 ) | |
240 | { | |
241 | bufr[end] = '\0'; | |
242 | rprintf(FERROR, "%s Badly formed line in configuration file: %s\n", | |
243 | func, bufr ); | |
244 | return( False ); | |
245 | } | |
246 | end = ( (i > 0) && (' ' == bufr[i - 1]) ) ? (i - 1) : (i); | |
247 | c = getc( InFile ); /* Continue with next line. */ | |
248 | break; | |
249 | ||
250 | default: /* All else are a valid name chars. */ | |
251 | if( isspace( c ) ) /* One space per whitespace region. */ | |
252 | { | |
253 | bufr[end] = ' '; | |
254 | i = end + 1; | |
255 | c = EatWhitespace( InFile ); | |
256 | } | |
257 | else /* All others copy verbatim. */ | |
258 | { | |
259 | bufr[i++] = c; | |
260 | end = i; | |
261 | c = getc( InFile ); | |
262 | } | |
263 | } | |
264 | } | |
265 | ||
266 | /* We arrive here if we've met the EOF before the closing bracket. */ | |
267 | rprintf(FERROR, "%s Unexpected EOF in the configuration file: %s\n", func, bufr ); | |
268 | return( False ); | |
269 | } /* Section */ | |
270 | ||
271 | static BOOL Parameter( FILE *InFile, BOOL (*pfunc)(char *, char *), int c ) | |
272 | /* ------------------------------------------------------------------------ ** | |
273 | * Scan a parameter name and value, and pass these two fields to pfunc(). | |
274 | * | |
275 | * Input: InFile - The input source. | |
276 | * pfunc - A pointer to the function that will be called to | |
277 | * process the parameter, once it has been scanned. | |
278 | * c - The first character of the parameter name, which | |
279 | * would have been read by Parse(). Unlike a comment | |
280 | * line or a section header, there is no lead-in | |
281 | * character that can be discarded. | |
282 | * | |
283 | * Output: True if the parameter name and value were scanned and processed | |
284 | * successfully, else False. | |
285 | * | |
286 | * Notes: This function is in two parts. The first loop scans the | |
287 | * parameter name. Internal whitespace is compressed, and an | |
288 | * equal sign (=) terminates the token. Leading and trailing | |
289 | * whitespace is discarded. The second loop scans the parameter | |
290 | * value. When both have been successfully identified, they are | |
291 | * passed to pfunc() for processing. | |
292 | * | |
293 | * ------------------------------------------------------------------------ ** | |
294 | */ | |
295 | { | |
296 | int i = 0; /* Position within bufr. */ | |
297 | int end = 0; /* bufr[end] is current end-of-string. */ | |
298 | int vstart = 0; /* Starting position of the parameter value. */ | |
299 | char *func = "params.c:Parameter() -"; | |
300 | ||
301 | /* Read the parameter name. */ | |
302 | while( 0 == vstart ) /* Loop until we've found the start of the value. */ | |
303 | { | |
304 | ||
305 | if( i > (bSize - 2) ) /* Ensure there's space for next char. */ | |
306 | { | |
307 | bSize += BUFR_INC; | |
308 | bufr = Realloc( bufr, bSize ); | |
309 | if( NULL == bufr ) | |
310 | { | |
311 | rprintf(FERROR, "%s Memory re-allocation failure.", func) ; | |
312 | return( False ); | |
313 | } | |
314 | } | |
315 | ||
316 | switch( c ) | |
317 | { | |
318 | case '=': /* Equal sign marks end of param name. */ | |
319 | if( 0 == end ) /* Don't allow an empty name. */ | |
320 | { | |
321 | rprintf(FERROR, "%s Invalid parameter name in config. file.\n", func ); | |
322 | return( False ); | |
323 | } | |
324 | bufr[end++] = '\0'; /* Mark end of string & advance. */ | |
325 | i = end; /* New string starts here. */ | |
326 | vstart = end; /* New string is parameter value. */ | |
327 | bufr[i] = '\0'; /* New string is nul, for now. */ | |
328 | break; | |
329 | ||
330 | case '\n': /* Find continuation char, else error. */ | |
331 | i = Continuation( bufr, i ); | |
332 | if( i < 0 ) | |
333 | { | |
334 | bufr[end] = '\0'; | |
335 | rprintf(FERROR, "%s Ignoring badly formed line in configuration file: %s\n", | |
336 | func, bufr ); | |
337 | return( True ); | |
338 | } | |
339 | end = ( (i > 0) && (' ' == bufr[i - 1]) ) ? (i - 1) : (i); | |
340 | c = getc( InFile ); /* Read past eoln. */ | |
341 | break; | |
342 | ||
343 | case '\0': /* Shouldn't have EOF within param name. */ | |
344 | case EOF: | |
345 | bufr[i] = '\0'; | |
346 | rprintf(FERROR, "%s Unexpected end-of-file at: %s\n", func, bufr ); | |
347 | return( True ); | |
348 | ||
349 | default: | |
350 | if( isspace( c ) ) /* One ' ' per whitespace region. */ | |
351 | { | |
352 | bufr[end] = ' '; | |
353 | i = end + 1; | |
354 | c = EatWhitespace( InFile ); | |
355 | } | |
356 | else /* All others verbatim. */ | |
357 | { | |
358 | bufr[i++] = c; | |
359 | end = i; | |
360 | c = getc( InFile ); | |
361 | } | |
362 | } | |
363 | } | |
364 | ||
365 | /* Now parse the value. */ | |
366 | c = EatWhitespace( InFile ); /* Again, trim leading whitespace. */ | |
367 | while( (EOF !=c) && (c > 0) ) | |
368 | { | |
369 | ||
370 | if( i > (bSize - 2) ) /* Make sure there's enough room. */ | |
371 | { | |
372 | bSize += BUFR_INC; | |
373 | bufr = Realloc( bufr, bSize ); | |
374 | if( NULL == bufr ) | |
375 | { | |
376 | rprintf(FERROR, "%s Memory re-allocation failure.", func) ; | |
377 | return( False ); | |
378 | } | |
379 | } | |
380 | ||
381 | switch( c ) | |
382 | { | |
383 | case '\r': /* Explicitly remove '\r' because the older */ | |
384 | c = getc( InFile ); /* version called fgets_slash() which also */ | |
385 | break; /* removes them. */ | |
386 | ||
387 | case '\n': /* Marks end of value unless there's a '\'. */ | |
388 | i = Continuation( bufr, i ); | |
389 | if( i < 0 ) | |
390 | c = 0; | |
391 | else | |
392 | { | |
393 | for( end = i; (end >= 0) && isspace(bufr[end]); end-- ) | |
394 | ; | |
395 | c = getc( InFile ); | |
396 | } | |
397 | break; | |
398 | ||
399 | default: /* All others verbatim. Note that spaces do */ | |
400 | bufr[i++] = c; /* not advance <end>. This allows trimming */ | |
401 | if( !isspace( c ) ) /* of whitespace at the end of the line. */ | |
402 | end = i; | |
403 | c = getc( InFile ); | |
404 | break; | |
405 | } | |
406 | } | |
407 | bufr[end] = '\0'; /* End of value. */ | |
408 | ||
409 | return( pfunc( bufr, &bufr[vstart] ) ); /* Pass name & value to pfunc(). */ | |
410 | } /* Parameter */ | |
411 | ||
412 | static BOOL Parse( FILE *InFile, | |
413 | BOOL (*sfunc)(char *), | |
414 | BOOL (*pfunc)(char *, char *) ) | |
415 | /* ------------------------------------------------------------------------ ** | |
416 | * Scan & parse the input. | |
417 | * | |
418 | * Input: InFile - Input source. | |
419 | * sfunc - Function to be called when a section name is scanned. | |
420 | * See Section(). | |
421 | * pfunc - Function to be called when a parameter is scanned. | |
422 | * See Parameter(). | |
423 | * | |
424 | * Output: True if the file was successfully scanned, else False. | |
425 | * | |
426 | * Notes: The input can be viewed in terms of 'lines'. There are four | |
427 | * types of lines: | |
428 | * Blank - May contain whitespace, otherwise empty. | |
429 | * Comment - First non-whitespace character is a ';' or '#'. | |
430 | * The remainder of the line is ignored. | |
431 | * Section - First non-whitespace character is a '['. | |
432 | * Parameter - The default case. | |
433 | * | |
434 | * ------------------------------------------------------------------------ ** | |
435 | */ | |
436 | { | |
437 | int c; | |
438 | ||
439 | c = EatWhitespace( InFile ); | |
440 | while( (EOF != c) && (c > 0) ) | |
441 | { | |
442 | switch( c ) | |
443 | { | |
444 | case '\n': /* Blank line. */ | |
445 | c = EatWhitespace( InFile ); | |
446 | break; | |
447 | ||
448 | case ';': /* Comment line. */ | |
449 | case '#': | |
450 | c = EatComment( InFile ); | |
451 | break; | |
452 | ||
453 | case '[': /* Section Header. */ | |
454 | if( !Section( InFile, sfunc ) ) | |
455 | return( False ); | |
456 | c = EatWhitespace( InFile ); | |
457 | break; | |
458 | ||
459 | case '\\': /* Bogus backslash. */ | |
460 | c = EatWhitespace( InFile ); | |
461 | break; | |
462 | ||
463 | default: /* Parameter line. */ | |
464 | if( !Parameter( InFile, pfunc, c ) ) | |
465 | return( False ); | |
466 | c = EatWhitespace( InFile ); | |
467 | break; | |
468 | } | |
469 | } | |
470 | return( True ); | |
471 | } /* Parse */ | |
472 | ||
473 | static FILE *OpenConfFile( char *FileName ) | |
474 | /* ------------------------------------------------------------------------ ** | |
475 | * Open a configuration file. | |
476 | * | |
477 | * Input: FileName - The pathname of the config file to be opened. | |
478 | * | |
479 | * Output: A pointer of type (FILE *) to the opened file, or NULL if the | |
480 | * file could not be opened. | |
481 | * | |
482 | * ------------------------------------------------------------------------ ** | |
483 | */ | |
484 | { | |
485 | FILE *OpenedFile; | |
486 | char *func = "params.c:OpenConfFile() -"; | |
487 | ||
488 | if( NULL == FileName || 0 == *FileName ) | |
489 | { | |
490 | rprintf(FERROR,"%s No configuration filename specified.\n", func); | |
491 | return( NULL ); | |
492 | } | |
493 | ||
494 | OpenedFile = fopen( FileName, "r" ); | |
495 | if( NULL == OpenedFile ) | |
496 | { | |
497 | rprintf(FERROR,"%s Unable to open configuration file \"%s\":\n\t%s\n", | |
498 | func, FileName, strerror(errno)); | |
499 | } | |
500 | ||
501 | return( OpenedFile ); | |
502 | } /* OpenConfFile */ | |
503 | ||
504 | BOOL pm_process( char *FileName, | |
505 | BOOL (*sfunc)(char *), | |
506 | BOOL (*pfunc)(char *, char *) ) | |
507 | /* ------------------------------------------------------------------------ ** | |
508 | * Process the named parameter file. | |
509 | * | |
510 | * Input: FileName - The pathname of the parameter file to be opened. | |
511 | * sfunc - A pointer to a function that will be called when | |
512 | * a section name is discovered. | |
513 | * pfunc - A pointer to a function that will be called when | |
514 | * a parameter name and value are discovered. | |
515 | * | |
516 | * Output: TRUE if the file was successfully parsed, else FALSE. | |
517 | * | |
518 | * ------------------------------------------------------------------------ ** | |
519 | */ | |
520 | { | |
521 | int result; | |
522 | FILE *InFile; | |
523 | char *func = "params.c:pm_process() -"; | |
524 | ||
525 | InFile = OpenConfFile( FileName ); /* Open the config file. */ | |
526 | if( NULL == InFile ) | |
527 | return( False ); | |
528 | ||
529 | if( NULL != bufr ) /* If we already have a buffer */ | |
530 | result = Parse( InFile, sfunc, pfunc ); /* (recursive call), then just */ | |
531 | /* use it. */ | |
532 | ||
533 | else /* If we don't have a buffer */ | |
534 | { /* allocate one, then parse, */ | |
535 | bSize = BUFR_INC; /* then free. */ | |
536 | bufr = (char *)malloc( bSize ); | |
537 | if( NULL == bufr ) | |
538 | { | |
539 | rprintf(FERROR,"%s memory allocation failure.\n", func); | |
540 | fclose(InFile); | |
541 | return( False ); | |
542 | } | |
543 | result = Parse( InFile, sfunc, pfunc ); | |
544 | free( bufr ); | |
545 | bufr = NULL; | |
546 | bSize = 0; | |
547 | } | |
548 | ||
549 | fclose(InFile); | |
550 | ||
551 | if( !result ) /* Generic failure. */ | |
552 | { | |
553 | rprintf(FERROR,"%s Failed. Error returned from params.c:parse().\n", func); | |
554 | return( False ); | |
555 | } | |
556 | ||
557 | return( True ); /* Generic success. */ | |
558 | } /* pm_process */ | |
559 | ||
560 | /* -------------------------------------------------------------------------- */ |