aboutsummaryrefslogtreecommitdiffstats
path: root/cfg.c
blob: 355022bee86d19b37111fa5416f4f7a52fd516a9 (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
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
/* $Id: cfg.c,v 1.34 2004/02/18 06:39:20 reinelt Exp $^
 *
 * config file stuff
 *
 * Copyright 1999, 2000 Michael Reinelt <reinelt@eunet.at>
 * Copyright 2004 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net>
 *
 * This file is part of LCD4Linux.
 *
 * LCD4Linux 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, or (at your option)
 * any later version.
 *
 * LCD4Linux 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *
 * $Log: cfg.c,v $
 * Revision 1.34  2004/02/18 06:39:20  reinelt
 * T6963 driver for graphic displays finished
 *
 * Revision 1.33  2004/02/01 18:08:50  reinelt
 * removed strtok() from layout processing (took me hours to find this bug)
 * further strtok() removind should be done!
 *
 * Revision 1.32  2004/01/30 20:57:55  reinelt
 * HD44780 patch from Martin Hejl
 * dmalloc integrated
 *
 * Revision 1.31  2004/01/29 04:40:02  reinelt
 * every .c file includes "config.h" now
 *
 * Revision 1.30  2004/01/22 07:57:45  reinelt
 * several bugs fixed where segfaulting on layout>display
 * Crystalfontz driver optimized, 632 display already works
 *
 * Revision 1.29  2004/01/18 06:54:08  reinelt
 * bug in expr.c fixed (thanks to Xavier)
 * some progress with /proc/stat parsing
 *
 * Revision 1.28  2004/01/16 05:04:53  reinelt
 * started plugin proc_stat which should parse /proc/stat
 * which again is a paint in the a**
 * thinking over implementation methods of delta functions
 * (CPU load, ...)
 *
 * Revision 1.27  2004/01/14 11:33:00  reinelt
 * new plugin 'uname' which does what it's called
 * text widget nearly finished
 * first results displayed on MatrixOrbital
 *
 * Revision 1.26  2004/01/11 18:26:02  reinelt
 * further widget and layout processing
 *
 * Revision 1.25  2004/01/11 09:26:15  reinelt
 * layout starts to exist...
 *
 * Revision 1.24  2004/01/10 20:22:33  reinelt
 * added new function 'cfg_list()' (not finished yet)
 * added layout.c (will replace processor.c someday)
 * added widget_text.c (will be the first and most important widget)
 * modified lcd4linux.c so that old-style configs should work, too
 *
 * Revision 1.23  2004/01/09 04:16:06  reinelt
 * added 'section' argument to cfg_get(), but NULLed it on all calls by now.
 *
 * Revision 1.22  2004/01/08 06:00:28  reinelt
 * allowed '.' in key names
 * allowed empty section keys (not only "section anything {", but "anything {")
 *
 * Revision 1.21  2004/01/08 05:28:12  reinelt
 * Luk Claes added to AUTHORS
 * cfg: section handling ('{}') added
 *
 * Revision 1.20  2004/01/07 10:15:41  reinelt
 * small glitch in evaluator fixed
 * made config table sorted and access with bsearch(),
 * which should be much faster
 *
 * Revision 1.19  2003/12/19 05:35:14  reinelt
 * renamed 'client' to 'plugin'
 *
 * Revision 1.18  2003/10/11 06:01:52  reinelt
 *
 * renamed expression.{c,h} to client.{c,h}
 * added config file client
 * new functions 'AddNumericVariable()' and 'AddStringVariable()'
 * new parameter '-i' for interactive mode
 *
 * Revision 1.17  2003/10/05 17:58:50  reinelt
 * libtool junk; copyright messages cleaned up
 *
 * Revision 1.16  2003/09/09 06:54:43  reinelt
 * new function 'cfg_number()'
 *
 * Revision 1.15  2003/08/24 05:17:58  reinelt
 * liblcd4linux patch from Patrick Schemitz
 *
 * Revision 1.14  2003/08/14 03:47:40  reinelt
 * remove PID file if driver initialisation fails
 *
 * Revision 1.13  2003/02/22 07:53:10  reinelt
 * cfg_get(key,defval)
 *
 * Revision 1.12  2001/03/09 12:14:24  reinelt
 *
 * minor cleanups
 *
 * Revision 1.11  2001/03/08 15:25:38  ltoetsch
 * improved exec
 *
 * Revision 1.10  2001/03/07 18:10:21  ltoetsch
 * added e(x)ec commands
 *
 * Revision 1.9  2000/08/10 09:44:09  reinelt
 *
 * new debugging scheme: error(), info(), debug()
 * uses syslog if in daemon mode
 *
 * Revision 1.8  2000/07/31 06:46:35  reinelt
 *
 * eliminated some compiler warnings with glibc
 *
 * Revision 1.7  2000/04/15 11:13:54  reinelt
 *
 * added '-d' (debugging) switch
 * added several debugging messages
 * removed config entry 'Delay' for HD44780 driver
 * delay loop for HD44780 will be calibrated automatically
 *
 * Revision 1.6  2000/04/03 04:46:38  reinelt
 *
 * added '-c key=val' option
 *
 * Revision 1.5  2000/03/28 07:22:15  reinelt
 *
 * version 0.95 released
 * X11 driver up and running
 * minor bugs fixed
 *
 * Revision 1.4  2000/03/26 20:00:44  reinelt
 *
 * README.Raster added
 *
 * Revision 1.3  2000/03/26 19:03:52  reinelt
 *
 * more Pixmap renaming
 * quoting of '#' in config file
 *
 * Revision 1.2  2000/03/10 17:36:02  reinelt
 *
 * first unstable but running release
 *
 * Revision 1.1  2000/03/10 11:40:47  reinelt
 * *** empty log message ***
 *
 * Revision 1.3  2000/03/07 11:01:34  reinelt
 *
 * system.c cleanup
 *
 * Revision 1.2  2000/03/06 06:04:06  reinelt
 *
 * minor cleanups
 *
 */

/* 
 * exported functions:
 *
 * cfg_init (source)
 *   read configuration from source
 *   returns  0 if successful
 *   returns -1 in case of an error
 * 
 * cfg_source (void)
 *   returns the file the configuration was read from
 * 
 * cfg_cmd (arg)
 *   allows us to overwrite entries in the 
 *   config-file from the command line.
 *   arg is 'key=value'
 *   cfg_cmd can be called _before_ cfg_read()
 *   returns 0 if ok, -1 if arg cannot be parsed
 *
 * cfg_list (section)
 *   returns a list of all keys in the specified section
 *   This list was allocated be cfg_list() and must be 
 *   freed by the caller!
 *
 * cfg_get_raw (section, key, defval) 
 *   return the a value for a given key in a given section 
 *   or <defval> if key does not exist. Does NOT evaluate
 *   the expression. Therefore used to get the expression 
 *   itself!
 *
 * cfg_get (section, key, defval) 
 *   return the a value for a given key in a given section 
 *   or <defval> if key does not exist. The specified
 *   value in the config is treated as a expression and 
 *   is evaluated!
 *
 * cfg_number (section, key, defval, min, int max, *value) 
 *   return the a value for a given key in a given section 
 *   convert it into a number with syntax checking
 *   check if its in a given range. As it uses cfg_get()
 *   internally, the evaluator is used here, too.
 * 
 */


#include "config.h"

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

#include <unistd.h>
#include <sys/stat.h>

#include "debug.h"
#include "evaluator.h"
#include "cfg.h"

#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif

typedef struct {
  char *key;
  char *val;
  int lock;
} ENTRY;


static char  *Config_File=NULL;
static ENTRY *Config=NULL;
static int   nConfig=0;


// bsearch compare function for config entries
static int c_lookup (const void *a, const void *b)
{
  char *key=(char*)a;
  ENTRY *entry=(ENTRY*)b;

  return strcasecmp(key, entry->key);
}


// qsort compare function for variables
static int c_sort (const void *a, const void *b)
{
  ENTRY *ea=(ENTRY*)a;
  ENTRY *eb=(ENTRY*)b;

  return strcasecmp(ea->key, eb->key);
}


// remove leading and trailing whitespace
static char *strip (char *s, int strip_comments)
{
  char *p;
  
  while (isblank(*s)) s++;
  for (p=s; *p; p++) {
    if (*p=='"')  do p++; while (*p && *p!='\n' && *p!='"');
    if (*p=='\'') do p++; while (*p && *p!='\n' && *p!='\'');
    if (*p=='\n' || (strip_comments && *p=='#' && (p==s || *(p-1)!='\\'))) {
      *p='\0';
      break;
    }
  }
  for (p--; p>s && isblank(*p); p--) *p='\0';
  return s;
}


// unquote a string
static char *dequote (char *string)
{
  char *s=string;
  char *p=string;
  
  do {
    if (*s=='\\' && *(s+1)=='#') {
      *p++=*++s;
    } else {
      *p++=*s;
    }
  } while (*s++);
  
  return string;
}


// which if a string contains only valid chars
// i.e. start with a char and contains chars and nums
static int validchars (char *string)
{
  char *c;

  for (c=string; *c; c++) {
    // first and following chars
    if ((*c>='A' && *c<='Z') || (*c>='a' && *c<='z') || (*c=='_')) continue;
    // only following chars
    if ((c>string) && ((*c>='0' && *c<='9') || (*c=='.') || (*c=='-'))) continue;
    return 0;
  }
  return 1;
}


static void cfg_add (char *section, char *key, char *val, int lock)
{
  char *buffer;
  ENTRY *entry;
  
  // allocate buffer 
  buffer=malloc(strlen(section)+strlen(key)+2);
  *buffer='\0';
  
  // prepare section.key
  if (section!=NULL && *section!='\0') {
    strcpy(buffer, section);
    strcat(buffer, ".");
  }
  strcat (buffer, key);
  
  // does the key already exist?
  entry=bsearch(buffer, Config, nConfig, sizeof(ENTRY), c_lookup);
  
  if (entry!=NULL) {
    if (entry->lock>lock) return;
    debug ("Warning: key <%s>: value <%s> overwritten with <%s>", buffer, entry->val, val);
    free (buffer);
    if (entry->val) free (entry->val);
    entry->val=dequote(strdup(val));
    return;
  }
  
  nConfig++;
  Config=realloc(Config, nConfig*sizeof(ENTRY));
  Config[nConfig-1].key=buffer;
  Config[nConfig-1].val=dequote(strdup(val));
  Config[nConfig-1].lock=lock;

  qsort(Config, nConfig, sizeof(ENTRY), c_sort);

}


int l4l_cfg_cmd (char *arg)
{
  char *key, *val;
  char buffer[256];
  
  strncpy (buffer, arg, sizeof(buffer));
  key=strip(buffer, 0);
  for (val=key; *val; val++) {
    if (*val=='=') {
      *val++='\0';
      break;
    }
  }
  if (*key=='\0' || *val=='\0') return -1;
  if (!validchars(key)) return -1;
  cfg_add ("", key, val, 1);
  return 0;
}


char *l4l_cfg_list (char *section)
{
  int i, len;
  char *key, *list;
  
  // calculate key length
  len=strlen(section)+1;

  // prepare search key
  key=malloc(len+1);
  strcpy (key, section);
  strcat (key, ".");
  
  // start with empty string
  list=malloc(1);
  *list='\0';
  
  // search matching entries
  for (i=0; i<nConfig; i++) {
    if (strncasecmp(Config[i].key, key, len)==0) {
      list=realloc(list, strlen(list)+strlen(Config[i].key)-len+2);
      if (*list!='\0') strcat (list, "|");
      strcat (list, Config[i].key+len);
    }
  }
  
  free (key);
  return list;
}


static char *cfg_lookup (char *section, char *key)
{
  int len;
  char *buffer;
  ENTRY *entry;

  // calculate key length
  len=strlen(key)+1;
  if (section!=NULL)
    len+=strlen(section)+1;

  // allocate buffer 
  buffer=malloc(len);
  *buffer='\0';
  
  // prepare section:key
  if (section!=NULL && *section!='\0') {
    strcpy(buffer, section);
    strcat(buffer, ".");
  }
  strcat (buffer, key);
  
  // search entry
  entry=bsearch(buffer, Config, nConfig, sizeof(ENTRY), c_lookup);

  // free buffer again
  free (buffer);
  
  if (entry!=NULL)
    return entry->val;

  return NULL;
}


char *l4l_cfg_get_raw (char *section, char *key, char *defval)
{
  char *val=cfg_lookup(section, key);
  
  if (val!=NULL) return val;
  return defval;
}


char *l4l_cfg_get (char *section, char *key, char *defval)
{
  char *expression;
  RESULT result = {0, 0.0, NULL};
  
  expression=cfg_lookup(section, key);
  
  if (expression!=NULL) {
    if (*expression=='\0') return "";
    if (Eval(expression, &result)==0) {
      return R2S(&result);
    }
  }
  return strdup(defval);
}


int l4l_cfg_number (char *section, char *key, int defval, int min, int max, int *value) 
{
  char *expression;
  RESULT result = {0, 0.0, NULL};
   
  // start with default value
  // in case of an (uncatched) error, you have the
  // default value set, which may be handy...
  *value=defval;

  expression=cfg_get_raw(section, key, NULL);
  if (expression==NULL) {
    return 0;
  }
  
  if (Eval(expression, &result)!=0) {
    return -1;
  }
  *value=R2N(&result);
  DelResult(&result);
  
  if (*value<min) {
    error ("bad %s value '%d' in %s, minimum is %d", key, *value, cfg_source(), min);
    *value=min;
    return -1;
  }
  
  if (*value>max) {
    error ("bad %s value '%d' in %s, maximum is %d", key, *value, cfg_source(), max);
    *value=max;
    return -1;
  }

  return 0;
}


static int cfg_check_source(char *file)
{
  /* as passwords and commands are stored in the config file,
   * we will check that:
   * - file is a normal file (or /dev/null)
   * - file owner is owner of program
   * - file is not accessible by group
   * - file is not accessible by other
   */

  struct stat stbuf;
  uid_t uid, gid;
  int error;

  uid = geteuid();
  gid = getegid();
  
  if (stat(file, &stbuf) == -1) {
    error ("stat(%s) failed: %s", file, strerror(errno));
    return -1;
  }
  if (S_ISCHR(stbuf.st_mode) && strcmp(file, "/dev/null") == 0)
    return 0;
  
  error=0;
  if (!S_ISREG(stbuf.st_mode)) {
    error ("security error: '%s' is not a regular file", file);
    error=-1;
  }
  if (stbuf.st_uid != uid || stbuf.st_gid != gid) {
    error ("security error: owner and/or group of '%s' don't match", file);
    error=-1;
  }
  if (stbuf.st_mode & S_IRWXG || stbuf.st_mode & S_IRWXO) {
    error ("security error: group or other have access to '%s'", file);
    error=-1;
  }
  return error;
}


static int cfg_read (char *file)
{
  FILE *stream;
  char buffer[256];
  char section[256];
  char *line, *key, *val, *end;
  int section_open, section_close;
  int error, lineno;
  
  stream=fopen (file, "r");
  if (stream==NULL) {
    error ("open(%s) failed: %s", file, strerror(errno));
    return -1;
  }

  // start with empty section
  strcpy(section, "");
  
  error=0;
  lineno=0;
  while ((line=fgets(buffer,256,stream))!=NULL) {

    // increment line number
    lineno++;
  
    // skip empty lines
    if (*(line=strip(line, 1))=='\0') continue;

    // reset section flags
    section_open=0;
    section_close=0;
    
    // key is first word
    key=line;
    
    // search first blank between key and value
    for (val=line; *val; val++) {
      if (isblank(*val)) {
	*val++='\0';
	break;
      }
    }

    // strip value
    val=strip(val, 1);

    // search end of value
    if (*val) for (end=val; *(end+1); end++);
    else end=val;

    // if last char is '{', a section has been opened
    if (*end=='{') {
      section_open=1;
      *end='\0';
      val=strip(val, 0);
    }

    // provess "value" in double-quotes
    if (*val=='"' && *end=='"') {
      *end='\0';
      val++;
    }

    // if key is '}', a section has been closed
    if (strcmp(key, "}")==0) {
      section_close=1;
      *key='\0';
    }

    // sanity check: '}' should be the only char in a line
    if (section_close && (section_open || *val!='\0')) {
      error ("error in config file '%s' line %d: garbage after '}'", file, lineno);
      error=1;
      break;
    }
    
    // check key for valid chars
    if (!validchars(key)) {
      error ("error in config file '%s' line %d: key '%s' is invalid", file, lineno, key);
      error=1;
      break;
    }

    // on section-open, check value for valid chars
    if (section_open && !validchars(val)) {
      error ("error in config file '%s' line %d: section '%s' is invalid", file, lineno, val);
      error=1;
      break;
    }

    // on section-open, append new section name
    if (section_open) {
      // is the section[] array big enough?
      if (strlen(section)+strlen(key)+3 > sizeof(section)) {
	error ("error in config file '%s' line %d: section buffer overflow", file, lineno);
	error=1;
	break;
      }
      if (*section!='\0') strcat (section, ".");
      strcat (section, key);
      if (*val!='\0') {
	strcat (section, ":");
	strcat (section, val);
      }
      continue;
    }

    // on section-close, remove last section name
    if (section_close) {
      // sanity check: section already empty?
      if (*section=='\0') {
	error ("error in config file '%s' line %d: unmatched closing brace", file, lineno);
	error=1;
	break;
      }
	
      end=strrchr(section, '.');
      if (end==NULL)
	*section='\0';
      else
	*end='\0';
      continue;
    }

    // finally: add key
    cfg_add (section, key, val, 0);
    
  }
  
  // sanity check: are the braces balanced?
  if (!error && *section!='\0') {
    error ("error in config file '%s' line %d: unbalanced braces", file, lineno);
    error=1;
  }

  fclose (stream);

  return -error;
}


int l4l_cfg_init (char *file)
{
  if (cfg_check_source(file) == -1) {
    error("config file '%s' is insecure, aborting", file);
    return -1;
  }
  
  if (cfg_read(file)<0) return -1;
  
  if (Config_File) free (Config_File);
  Config_File=strdup(file);
  
  return 0;
}


char *l4l_cfg_source (void)
{
  if (Config_File)
    return Config_File;
  else
    return "";
}


int l4l_cfg_exit (void)
{
  int i;
  
  for (i=0; i<nConfig; i++) {
    if (Config[i].key) free (Config[i].key);
    if (Config[i].val) free (Config[i].val);
  }
  
  if (Config) {
    free (Config);
    Config=NULL;
  }

  if (Config_File) {
    free (Config_File);
    Config_File=NULL;
  }
  
  return 0;
}


int   (*cfg_init)    (char *source)                           = l4l_cfg_init;
char *(*cfg_source)  (void)                                   = l4l_cfg_source;
int   (*cfg_cmd)     (char *arg)                              = l4l_cfg_cmd;
char *(*cfg_list)    (char *section)                          = l4l_cfg_list;
char *(*cfg_get_raw) (char *section, char *key, char *defval) = l4l_cfg_get_raw;
char *(*cfg_get)     (char *section, char *key, char *defval) = l4l_cfg_get;
int   (*cfg_number)  (char *section, char *key, int   defval, 
		      int min, int max, int *value)           = l4l_cfg_number;
int   (*cfg_exit)    (void)                                   = l4l_cfg_exit;