aboutsummaryrefslogtreecommitdiffstats
path: root/cfg.c
blob: fe1a5515531effb55f28e757b1ae28899fc9c062 (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
/* $Id$
 * $URL$
 * $URL$
 *
 * config file stuff
 *
 * Copyright (C) 1999, 2000 Michael Reinelt <michael@reinelt.co.at>
 * Copyright (C) 2004, 2009 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.
 *
 */

/* 
 * 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_rename (section, old, new)
 *   changes the key of a existing entry
 *
 * 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, const int strip_comments)
{
    char *p;

    while (isblank(*s))
	s++;

    for (p = s; *p; p++) {
	if (*p == '"')
	    do
		p++;
	    while (*p && *p != '\n' && *p != '\r' && *p != '"');
	if (*p == '\'')
	    do
		p++;
	    while (*p && *p != '\n' && *p != '\r' && *p != '\'');
	if (*p == '\n' || (strip_comments && *p == '#' && (p == s || *(p - 1) != '\\'))) {
	    *p = '\0';
	    break;
	}
	if (*p == '\r' && *(p + 1) == '\n') {
	    /* replace <CR> from DOS <CR><LF> with blank */
	    *p = ' ';
	}
    }

    for (p--; p > s && isblank(*p); p--)
	*p = '\0';

    return s;
}


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

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


static void cfg_add(const char *section, const char *key, const char *val, const 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 = strdup(val);
	return;
    }

    nConfig++;
    Config = realloc(Config, nConfig * sizeof(ENTRY));
    Config[nConfig - 1].key = buffer;
    Config[nConfig - 1].val = strdup(val);
    Config[nConfig - 1].lock = lock;

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

}


int cfg_cmd(const char *arg)
{
    char *key, *val;
    char *buffer;

    buffer = strdup(arg);
    key = strip(buffer, 0);
    for (val = key; *val; val++) {
	if (*val == '=') {
	    *val++ = '\0';
	    break;
	}
    }
    if (*key == '\0' || *val == '\0') {
	free(buffer);
	return -1;
    }

    if (!validchars(key, 0)) {
	free(buffer);
	return -1;
    }

    cfg_add("", key, val, 1);

    free(buffer);
    return 0;
}


char *cfg_list(const 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;
}


int cfg_rename(const char *section, const char *old, const char *new)
{
    char *buffer;
    ENTRY *old_entry, *new_entry;

    /* prepare old section.key */
    buffer = malloc(strlen(section) + strlen(old) + 2);
    *buffer = '\0';
    if (section != NULL && *section != '\0') {
	strcpy(buffer, section);
	strcat(buffer, ".");
    }
    strcat(buffer, old);

    /* lookup old entry */
    old_entry = bsearch(buffer, Config, nConfig, sizeof(ENTRY), c_lookup);
    free(buffer);

    if (old_entry == NULL) {
	error("internal error: cfg_rename(%s, %s, %s) failed: entry not found!", section, old, new);
	return -1;
    }

    /* prepare new section.key */
    buffer = malloc(strlen(section) + strlen(new) + 2);
    *buffer = '\0';
    if (section != NULL && *section != '\0') {
	strcpy(buffer, section);
	strcat(buffer, ".");
    }
    strcat(buffer, new);

    /* lookup new entry */
    new_entry = bsearch(buffer, Config, nConfig, sizeof(ENTRY), c_lookup);

    if (new_entry != NULL) {
	info("cfg_rename(%s, %s, %s) failed: entry already exists!", section, old, new);
	free(buffer);
	return -1;
    }

    /* replace key */
    free(old_entry->key);
    old_entry->key = buffer;

    /* sort table again */
    qsort(Config, nConfig, sizeof(ENTRY), c_sort);

    return 0;
}


static char *cfg_lookup(const char *section, const 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 *cfg_get_raw(const char *section, const char *key, const char *defval)
{
    char *val = cfg_lookup(section, key);

    if (val != NULL)
	return val;

    return (char *) defval;
}


char *cfg_get(const char *section, const char *key, const char *defval)
{
    char *expression;
    char *retval;
    void *tree = NULL;
    RESULT result = { 0, 0, 0, NULL };

    expression = cfg_lookup(section, key);

    if (expression != NULL) {
	if (*expression == '\0')
	    return "";
	if (Compile(expression, &tree) == 0 && Eval(tree, &result) == 0) {
	    retval = strdup(R2S(&result));
	    DelTree(tree);
	    DelResult(&result);
	    return (retval);
	}
	DelTree(tree);
	DelResult(&result);
    }
    if (defval)
	return strdup(defval);
    return NULL;
}


int cfg_number(const char *section, const char *key, const int defval, const int min, const int max, int *value)
{
    char *expression;
    void *tree = NULL;
    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 || *expression == '\0') {
	return 0;
    }

    if (Compile(expression, &tree) != 0) {
	DelTree(tree);
	return -1;
    }
    if (Eval(tree, &result) != 0) {
	DelTree(tree);
	DelResult(&result);
	return -1;
    }
    *value = R2N(&result);
    DelTree(tree);
    DelResult(&result);

    if (*value < min) {
	error("bad '%s.%s' value '%d' in %s, minimum is %d", section, key, *value, cfg_source(), min);
	*value = min;
	return -1;
    }

    if (max > min && max != -1 && *value > max) {
	error("bad '%s.%s' value '%d' in %s, maximum is %d", section, key, *value, cfg_source(), max);
	*value = max;
	return -1;
    }

    return 1;
}


static int cfg_check_source(const 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 ! defined(__CYGWIN__)
    if (stbuf.st_mode & S_IRWXG || stbuf.st_mode & S_IRWXO) {
	error("security error: group or other have access to '%s'", file);
	error = -1;
    }
#endif
    return error;
}


static int cfg_read(const 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, 0)) {
	    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, 1)) {
	    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;
}


static void cfg_dump(void)
{
    int i, len;

    /* find longest key for pretty output */
    len = 1;
    for (i = 0; i < nConfig; i++) {
	int l = strlen(Config[i].key);
	if (l > len)
	    len = l;
    }

    info("Dump of %s:", Config_File);
    for (i = 0; i < nConfig; i++) {
	info("  %-*s %s", len, Config[i].key, Config[i].val);
    }
    info(" ");
}


int cfg_init(const char *file)
{
    if (cfg_check_source(file) == -1) {
	return -1;
    }

    if (cfg_read(file) < 0)
	return -1;

    if (Config_File)
	free(Config_File);

    Config_File = strdup(file);

    if (verbose_level > 1)
	cfg_dump();

    return 0;
}


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


int 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;
}