summaryrefslogtreecommitdiffstats
path: root/discover/params.c
blob: 09c2b0f640a12b6d8c641fb45b64389ae8f83d41 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
/* This modules is based on the params.c module from Samba, written by Karl Auer
   and much modifed by Christopher Hertel. */

/*
 * This program 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.
 *
 * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>

#include <log/log.h>

#include "params.h"

#define new_array(type, num) ((type *)_new_array(sizeof(type), (num)))
#define realloc_array(ptr, type, num) \
	((type *)_realloc_array((ptr), sizeof(type), (num)))

#define rprintf(x, ...) do {pb_log(__VA_ARGS__); pb_log("\n");} while (0)
#define rsyserr(x, y, ...) do {pb_log(__VA_ARGS__); pb_log("\n");} while (0)

#define MALLOC_MAX 0x40000000
#define False 0
#define True 1

static void *_new_array(unsigned int size, unsigned long num)
{
	if (num >= MALLOC_MAX/size)
		return NULL;
	return malloc(size * num);
}

static void *_realloc_array(void *ptr, unsigned int size, unsigned long num)
{
	if (num >= MALLOC_MAX/size)
		return NULL;
	/* No realloc should need this, but just in case... */
	if (!ptr)
		return malloc(size * num);
	return realloc(ptr, size * num);
}


/* -------------------------------------------------------------------------- **
 *
 * Module name: params
 *
 * -------------------------------------------------------------------------- **
 *
 *  This module performs lexical analysis and initial parsing of a
 *  Windows-like parameter file.  It recognizes and handles four token
 *  types:  section-name, parameter-name, parameter-value, and
 *  end-of-file.  Comments and line continuation are handled
 *  internally.
 *
 *  The entry point to the module is function pm_process().  This
 *  function opens the source file, calls the Parse() function to parse
 *  the input, and then closes the file when either the EOF is reached
 *  or a fatal error is encountered.
 *
 *  A sample parameter file might look like this:
 *
 *  [section one]
 *  parameter one = value string
 *  parameter two = another value
 *  [section two]
 *  new parameter = some value or t'other
 *
 *  The parameter file is divided into sections by section headers:
 *  section names enclosed in square brackets (eg. [section one]).
 *  Each section contains parameter lines, each of which consist of a
 *  parameter name and value delimited by an equal sign.  Roughly, the
 *  syntax is:
 *
 *    <file>            :==  { <section> } EOF
 *
 *    <section>         :==  <section header> { <parameter line> }
 *
 *    <section header>  :==  '[' NAME ']'
 *
 *    <parameter line>  :==  NAME '=' VALUE '\n'
 *
 *  Blank lines and comment lines are ignored.  Comment lines are lines
 *  beginning with either a semicolon (';') or a pound sign ('#').
 *
 *  All whitespace in section names and parameter names is compressed
 *  to single spaces.  Leading and trailing whitespace is stipped from
 *  both names and values.
 *
 *  Only the first equals sign in a parameter line is significant.
 *  Parameter values may contain equals signs, square brackets and
 *  semicolons.  Internal whitespace is retained in parameter values,
 *  with the exception of the '\r' character, which is stripped for
 *  historic reasons.  Parameter names may not start with a left square
 *  bracket, an equal sign, a pound sign, or a semicolon, because these
 *  are used to identify other tokens.
 *
 * -------------------------------------------------------------------------- **
 */

/* -------------------------------------------------------------------------- **
 * Constants...
 */

#define BUFR_INC 1024


/* -------------------------------------------------------------------------- **
 * Variables...
 *
 *  bufr        - pointer to a global buffer.  This is probably a kludge,
 *                but it was the nicest kludge I could think of (for now).
 *  bSize       - The size of the global buffer <bufr>.
 */

static char *bufr  = NULL;
static int   bSize = 0;

/* -------------------------------------------------------------------------- **
 * Functions...
 */

static int EatWhitespace( FILE *InFile )
  /* ------------------------------------------------------------------------ **
   * Scan past whitespace (see ctype(3C)) and return the first non-whitespace
   * character, or newline, or EOF.
   *
   *  Input:  InFile  - Input source.
   *
   *  Output: The next non-whitespace character in the input stream.
   *
   *  Notes:  Because the config files use a line-oriented grammar, we
   *          explicitly exclude the newline character from the list of
   *          whitespace characters.
   *        - Note that both EOF (-1) and the nul character ('\0') are
   *          considered end-of-file markers.
   *
   * ------------------------------------------------------------------------ **
   */
  {
  int c;

  for( c = getc( InFile ); isspace( c ) && ('\n' != c); c = getc( InFile ) )
    ;
  return( c );
  } /* EatWhitespace */

static int EatComment( FILE *InFile )
  /* ------------------------------------------------------------------------ **
   * Scan to the end of a comment.
   *
   *  Input:  InFile  - Input source.
   *
   *  Output: The character that marks the end of the comment.  Normally,
   *          this will be a newline, but it *might* be an EOF.
   *
   *  Notes:  Because the config files use a line-oriented grammar, we
   *          explicitly exclude the newline character from the list of
   *          whitespace characters.
   *        - Note that both EOF (-1) and the nul character ('\0') are
   *          considered end-of-file markers.
   *
   * ------------------------------------------------------------------------ **
   */
  {
  int c;

  for( c = getc( InFile ); ('\n'!=c) && (EOF!=c) && (c>0); c = getc( InFile ) )
    ;
  return( c );
  } /* EatComment */

static int Continuation( char *line, int pos )
  /* ------------------------------------------------------------------------ **
   * Scan backards within a string to discover if the last non-whitespace
   * character is a line-continuation character ('\\').
   *
   *  Input:  line  - A pointer to a buffer containing the string to be
   *                  scanned.
   *          pos   - This is taken to be the offset of the end of the
   *                  string.  This position is *not* scanned.
   *
   *  Output: The offset of the '\\' character if it was found, or -1 to
   *          indicate that it was not.
   *
   * ------------------------------------------------------------------------ **
   */
  {
  pos--;
  while( (pos >= 0) && isspace(((unsigned char *)line)[pos]) )
     pos--;

  return( ((pos >= 0) && ('\\' == line[pos])) ? pos : -1 );
  } /* Continuation */


static BOOL Section( FILE *InFile, BOOL (*sfunc)(char *) )
  /* ------------------------------------------------------------------------ **
   * Scan a section name, and pass the name to function sfunc().
   *
   *  Input:  InFile  - Input source.
   *          sfunc   - Pointer to the function to be called if the section
   *                    name is successfully read.
   *
   *  Output: True if the section name was read and True was returned from
   *          <sfunc>.  False if <sfunc> failed or if a lexical error was
   *          encountered.
   *
   * ------------------------------------------------------------------------ **
   */
  {
  int   c;
  int   i;
  int   end;
  char *func  = "params.c:Section() -";

  i = 0;      /* <i> is the offset of the next free byte in bufr[] and  */
  end = 0;    /* <end> is the current "end of string" offset.  In most  */
              /* cases these will be the same, but if the last          */
              /* character written to bufr[] is a space, then <end>     */
              /* will be one less than <i>.                             */

  c = EatWhitespace( InFile );    /* We've already got the '['.  Scan */
                                  /* past initial white space.        */

  while( (EOF != c) && (c > 0) )
    {

    /* Check that the buffer is big enough for the next character. */
    if( i > (bSize - 2) )
      {
      bSize += BUFR_INC;
      bufr   = realloc_array( bufr, char, bSize );
      if( NULL == bufr )
        {
        rprintf(FERROR, "%s Memory re-allocation failure.", func);
        return( False );
        }
      }

    /* Handle a single character. */
    switch( c )
      {
      case ']':                       /* Found the closing bracket.         */
        bufr[end] = '\0';
        if( 0 == end )                  /* Don't allow an empty name.       */
          {
          rprintf(FERROR, "%s Empty section name in configuration file.\n", func );
          return( False );
          }
        if( !sfunc( bufr ) )            /* Got a valid name.  Deal with it. */
          return( False );
        (void)EatComment( InFile );     /* Finish off the line.             */
        return( True );

      case '\n':                      /* Got newline before closing ']'.    */
        i = Continuation( bufr, i );    /* Check for line continuation.     */
        if( i < 0 )
          {
          bufr[end] = '\0';
          rprintf(FERROR, "%s Badly formed line in configuration file: %s\n",
                   func, bufr );
          return( False );
          }
        end = ( (i > 0) && (' ' == bufr[i - 1]) ) ? (i - 1) : (i);
        c = getc( InFile );             /* Continue with next line.         */
        break;

      default:                        /* All else are a valid name chars.   */
        if( isspace( c ) )              /* One space per whitespace region. */
          {
          bufr[end] = ' ';
          i = end + 1;
          c = EatWhitespace( InFile );
          }
        else                            /* All others copy verbatim.        */
          {
          bufr[i++] = c;
          end = i;
          c = getc( InFile );
          }
      }
    }

  /* We arrive here if we've met the EOF before the closing bracket. */
  rprintf(FERROR, "%s Unexpected EOF in the configuration file: %s\n", func, bufr );
  return( False );
  } /* Section */

static BOOL Parameter( FILE *InFile, BOOL (*pfunc)(char *, char *), int c )
  /* ------------------------------------------------------------------------ **
   * Scan a parameter name and value, and pass these two fields to pfunc().
   *
   *  Input:  InFile  - The input source.
   *          pfunc   - A pointer to the function that will be called to
   *                    process the parameter, once it has been scanned.
   *          c       - The first character of the parameter name, which
   *                    would have been read by Parse().  Unlike a comment
   *                    line or a section header, there is no lead-in
   *                    character that can be discarded.
   *
   *  Output: True if the parameter name and value were scanned and processed
   *          successfully, else False.
   *
   *  Notes:  This function is in two parts.  The first loop scans the
   *          parameter name.  Internal whitespace is compressed, and an
   *          equal sign (=) terminates the token.  Leading and trailing
   *          whitespace is discarded.  The second loop scans the parameter
   *          value.  When both have been successfully identified, they are
   *          passed to pfunc() for processing.
   *
   * ------------------------------------------------------------------------ **
   */
  {
  int   i       = 0;    /* Position within bufr. */
  int   end     = 0;    /* bufr[end] is current end-of-string. */
  int   vstart  = 0;    /* Starting position of the parameter value. */
  char *func    = "params.c:Parameter() -";

  /* Read the parameter name. */
  while( 0 == vstart )  /* Loop until we've found the start of the value. */
    {

    if( i > (bSize - 2) )       /* Ensure there's space for next char.    */
      {
      bSize += BUFR_INC;
      bufr   = realloc_array( bufr, char, bSize );
      if( NULL == bufr )
        {
        rprintf(FERROR, "%s Memory re-allocation failure.", func) ;
        return( False );
        }
      }

    switch( c )
      {
      case '=':                 /* Equal sign marks end of param name. */
        if( 0 == end )              /* Don't allow an empty name.      */
          {
          rprintf(FERROR, "%s Invalid parameter name in config. file.\n", func );
          return( False );
          }
        bufr[end++] = '\0';         /* Mark end of string & advance.   */
        i       = end;              /* New string starts here.         */
        vstart  = end;              /* New string is parameter value.  */
        bufr[i] = '\0';             /* New string is nul, for now.     */
        break;

      case '\n':                /* Find continuation char, else error. */
        i = Continuation( bufr, i );
        if( i < 0 )
          {
          bufr[end] = '\0';
          rprintf(FERROR, "%s Ignoring badly formed line in configuration file: %s\n",
                   func, bufr );
          return( True );
          }
        end = ( (i > 0) && (' ' == bufr[i - 1]) ) ? (i - 1) : (i);
        c = getc( InFile );       /* Read past eoln.                   */
        break;

      case '\0':                /* Shouldn't have EOF within param name. */
      case EOF:
        bufr[i] = '\0';
        rprintf(FERROR, "%s Unexpected end-of-file at: %s\n", func, bufr );
        return( True );

      default:
        if( isspace( c ) )     /* One ' ' per whitespace region.       */
          {
          bufr[end] = ' ';
          i = end + 1;
          c = EatWhitespace( InFile );
          }
        else                   /* All others verbatim.                 */
          {
          bufr[i++] = c;
          end = i;
          c = getc( InFile );
          }
      }
    }

  /* Now parse the value. */
  c = EatWhitespace( InFile );  /* Again, trim leading whitespace. */
  while( (EOF !=c) && (c > 0) )
    {

    if( i > (bSize - 2) )       /* Make sure there's enough room. */
      {
      bSize += BUFR_INC;
      bufr   = realloc_array( bufr, char, bSize );
      if( NULL == bufr )
        {
        rprintf(FERROR, "%s Memory re-allocation failure.", func) ;
        return( False );
        }
      }

    switch( c )
      {
      case '\r':              /* Explicitly remove '\r' because the older */
        c = getc( InFile );   /* version called fgets_slash() which also  */
        break;                /* removes them.                            */

      case '\n':              /* Marks end of value unless there's a '\'. */
        i = Continuation( bufr, i );
        if( i < 0 )
          c = 0;
        else
          {
          for( end = i; (end >= 0) && isspace(((unsigned char *) bufr)[end]); end-- )
            ;
          c = getc( InFile );
          }
        break;

      default:               /* All others verbatim.  Note that spaces do */
        bufr[i++] = c;       /* not advance <end>.  This allows trimming  */
        if( !isspace( c ) )  /* of whitespace at the end of the line.     */
          end = i;
        c = getc( InFile );
        break;
      }
    }
  bufr[end] = '\0';          /* End of value. */

  return( pfunc( bufr, &bufr[vstart] ) );   /* Pass name & value to pfunc().  */
  } /* Parameter */

static BOOL Parse( FILE *InFile,
                   BOOL (*sfunc)(char *),
                   BOOL (*pfunc)(char *, char *) )
  /* ------------------------------------------------------------------------ **
   * Scan & parse the input.
   *
   *  Input:  InFile  - Input source.
   *          sfunc   - Function to be called when a section name is scanned.
   *                    See Section().
   *          pfunc   - Function to be called when a parameter is scanned.
   *                    See Parameter().
   *
   *  Output: True if the file was successfully scanned, else False.
   *
   *  Notes:  The input can be viewed in terms of 'lines'.  There are four
   *          types of lines:
   *            Blank      - May contain whitespace, otherwise empty.
   *            Comment    - First non-whitespace character is a ';' or '#'.
   *                         The remainder of the line is ignored.
   *            Section    - First non-whitespace character is a '['.
   *            Parameter  - The default case.
   * 
   * ------------------------------------------------------------------------ **
   */
  {
  int    c;

  c = EatWhitespace( InFile );
  while( (EOF != c) && (c > 0) )
    {
    switch( c )
      {
      case '\n':                        /* Blank line. */
        c = EatWhitespace( InFile );
        break;

      case ';':                         /* Comment line. */
      case '#':
        c = EatComment( InFile );
        break;

      case '[':                         /* Section Header. */
	      if (!sfunc) return True;
	      if( !Section( InFile, sfunc ) )
		      return( False );
	      c = EatWhitespace( InFile );
	      break;

      case '\\':                        /* Bogus backslash. */
        c = EatWhitespace( InFile );
        break;

      default:                          /* Parameter line. */
        if( !Parameter( InFile, pfunc, c ) )
          return( False );
        c = EatWhitespace( InFile );
        break;
      }
    }
  return( True );
  } /* Parse */

static FILE *OpenConfFile( char *FileName )
  /* ------------------------------------------------------------------------ **
   * Open a configuration file.
   *
   *  Input:  FileName  - The pathname of the config file to be opened.
   *
   *  Output: A pointer of type (FILE *) to the opened file, or NULL if the
   *          file could not be opened.
   *
   * ------------------------------------------------------------------------ **
   */
  {
  FILE *OpenedFile;
  char *func = "params.c:OpenConfFile() -";

  if( NULL == FileName || 0 == *FileName )
    {
    rprintf(FERROR,"%s No configuration filename specified.\n", func);
    return( NULL );
    }

  OpenedFile = fopen( FileName, "r" );
  if( NULL == OpenedFile )
    {
    rsyserr(FERROR, errno, "unable to open configuration file \"%s\"",
	    FileName);
    }

  return( OpenedFile );
  } /* OpenConfFile */

BOOL pm_process( char *FileName,
                 BOOL (*sfunc)(char *),
                 BOOL (*pfunc)(char *, char *) )
  /* ------------------------------------------------------------------------ **
   * Process the named parameter file.
   *
   *  Input:  FileName  - The pathname of the parameter file to be opened.
   *          sfunc     - A pointer to a function that will be called when
   *                      a section name is discovered.
   *          pfunc     - A pointer to a function that will be called when
   *                      a parameter name and value are discovered.
   *
   *  Output: TRUE if the file was successfully parsed, else FALSE.
   *
   * ------------------------------------------------------------------------ **
   */
  {
  int   result;
  FILE *InFile;
  char *func = "params.c:pm_process() -";

  InFile = OpenConfFile( FileName );          /* Open the config file. */
  if( NULL == InFile )
    return( False );

  if( NULL != bufr )                          /* If we already have a buffer */
    result = Parse( InFile, sfunc, pfunc );   /* (recursive call), then just */
                                              /* use it.                     */

  else                                        /* If we don't have a buffer   */
    {                                         /* allocate one, then parse,   */
    bSize = BUFR_INC;                         /* then free.                  */
    bufr = new_array( char, bSize );
    if( NULL == bufr )
      {
      rprintf(FERROR,"%s memory allocation failure.\n", func);
      fclose(InFile);
      return( False );
      }
    result = Parse( InFile, sfunc, pfunc );
    free( bufr );
    bufr  = NULL;
    bSize = 0;
    }

  fclose(InFile);

  if( !result )                               /* Generic failure. */
    {
    rprintf(FERROR,"%s Failed.  Error returned from params.c:parse().\n", func);
    return( False );
    }

  return( True );                             /* Generic success. */
  } /* pm_process */

/* -------------------------------------------------------------------------- */

OpenPOWER on IntegriCloud