summaryrefslogtreecommitdiffstats
path: root/parseconfig.c
blob: 3a763bc0c9f072cea1f26e620b2e90f8d62116f5 (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
#ident "$Id$"
/* ----------------------------------------------------------------------- *
 *   
 *   Copyright 1995-1998 H. Peter Anvin - All Rights Reserved
 *
 *   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, Inc., 675 Mass Ave, Cambridge MA 02139,
 *   USA; either version 2 of the License, or (at your option) any later
 *   version; incorporated herein by reference.
 *
 * ----------------------------------------------------------------------- */

/*
 * parseconfig.c
 * 
 * Routine library for parsing the configuration file
 *
 */

#include "magicfilter.h"

/*
 * int getoffset(char *startpos, char **endpos)
 *
 * Returns the parsing offset (a decimal, octal or hex number, or "default").
 * Returns the number, or one of the negative numbers
 *    MAG_DEFAULT      ... is default
 *    MAG_COMMENT      ... comment line
 *    MAG_ERR          ... invalid offset
 *
 * *endpos is set to the first character after the offset, unless NULL
 */

int getoffset(char *p, char **endpos)
{
  int offset = 0;		/* So far */
  enum { st_start, st_zero, st_oct, st_dec, st_hex, st_done } state = st_start;

#if DEBUG > 3
  fprintf(stderr,"getoffset %s\n", p);
#endif

  while ( isspace(*p) ) p++;	/* Skip leading whitespace */

  while ( state != st_done )
    {
      switch( state )
	{
	case st_start:
	  switch ( *p )
	    {
	    case '\b':		/* Whitespace */
	    case '\t':
	    case '\n':
	    case '\v':
	    case '\f':
	    case '\r':
	    case ' ':
	      p++;
	      break;
	      
	    case '#':
	    case '\0':		/* Blank line counts as comment */
	      offset = MAG_COMMENT;
	      state = st_done;
	      break;

	    case '0':
	      state = st_zero;
	      p++;
	      break;

	    case '1':
	    case '2':
	    case '3':
	    case '4':
	    case '5':
	    case '6':
	    case '7':
	    case '8':
	    case '9':
	      offset = *p - '0';
	      state = st_dec;
	      p++;
	      break;
	      
	    case 'd':
	      if ( strncmp(p, "default", 7) )
		{
		  offset = MAG_ERR;
		}
	      else
		{
		  p += 7;
		  offset = MAG_DEFAULT;
		}
	      state = st_done;
	      break;

	    default:
	      offset = MAG_ERR;
	      state = st_done;
	      break;
	    }
	  break;

	case st_zero:
	  if ( *p == 'x' || *p == 'X' )
	    {
	      state = st_hex;
	      p++;
	      break;
	    }
	  /* else fall through */

	case st_oct:
	  if ( *p < '0' || *p > '7' )
	    {
	      state = st_done;
	    }
	  else
	    {
	      offset <<= 3;
	      offset += *(p++) - '0';
	    }
	  break;

	case st_dec:
	  if ( *p < '0' || *p > '9' )
	    {
	      state = st_done;
	    }
	  else
	    {
	      offset *= 10;
	      offset += *(p++) - '0';
	    }
	  break;

	case st_hex:
	  if ( *p >= '0' && *p <= '9' )
	    {
	      offset <<= 4;
	      offset += *(p++) - '0';
	    }
	  else if ( *p >= 'A' && *p <= 'F' )
	    {
	      offset <<= 4;
	      offset += *(p++) - 'A' + 10;
	    }
	  else if ( *p >= 'a' && *p <= 'f' )
	    {
	      offset <<= 4;
	      offset += *(p++) - 'a' + 10;
	    }
	  else
	    {
	      state = st_done;
	    }
	}
    }

  if ( endpos )
    *endpos = p;		/* Where did we end? */

  return offset;
}

/*
 * int getmagic(char *startpos, char **endpos, char *magic, char *mask)
 *
 * Parse a magic string, returning the number of bytes in the magic string.
 * Stores the endpoint in *endpos if requested.  If magic and/or mask
 * is NULL, do not store; used to count the number of characters in the
 * magic/mask string.
 *
 * Each character in mask is either 0 for \? (don't care) or (char)-1 for
 * any other (do care).
 *
 * If mask is set to the senitel value NO_WILD (a unique pointer value
 * pointing to a bogus static string) the \? will not be interpreted
 * as don't care; just as a regular escaped questionmark.
 *
 */
char NO_WILD[1] = "";		/* Used as senitel value */

int getmagic(char *p, char **endpos, char *magic, char *mask)
{
  int count = 0;		/* Count of bytes */
  int quote = 0;		/* Quoted? */
  int ch;
  int wildcards = 1;		/* Wildcards allowed by default */
  enum { st_def, st_backsl, st_oct, st_hex, st_done } state = st_def;

#if DEBUG > 3
  fprintf(stderr,"getmagic %s\n", p);
#endif

  if ( mask == NO_WILD )	/* If wildcards forbidden */
    {
      mask = NULL;		/* Don't store a mask */
      wildcards = 0;		/* Don't accept wildcards */
    }

  while ( isspace(*p) ) p++;	/* Skip leading whitespace */
  
  while ( state != st_done )
    {
      switch ( state )
	{
	case st_def:
	  switch ( *p )
	    {
	    case '\n':		/* Unconditional whitespace */
	    case '\r':
	    case '\f':
	    case '\0':
	      if ( quote )
		count = MAG_ERR;
	      state = st_done;
	      break;

	    case '\\':		/* Backslash */
	      p++;
	      state = st_backsl;
	      break;

	    case '\"':		/* Quote */
	      p++;
	      quote = !quote;
	      break;

	    case '\b':		/* Whitespace */
	    case '\t':
	    case '\v':
	    case ' ':
	      if ( !quote )
		{
		  state = st_done;
		  break;
		}
	      /* else fall though */

	    default:
	      if ( magic ) *(magic++) = *p;
	      if ( mask ) *(mask++) = (char)(-1);
	      p++; count++;
	      break;
	    }
	  break;
	  
	case st_backsl:		/* After backslash */
	  ch = -1;
	  switch ( *p )
	    {
	    case 'a':
	      ch = 7;		/* Bell */
	      break;
	    case 'b':
	      ch = '\b';	/* Backspace */
	      break;
	    case 'e':
	      ch = 27;		/* Escape */
	      break;
	    case 'f':
	      ch = '\f';	/* Form feed */
	      break;
	    case 'n':
	      ch = '\n';	/* Newline */
	      break;
	    case 'r':
	      ch = '\r';	/* Return */
	      break;
	    case 't':
	      ch = '\t';	/* Tab */
	      break;
	    case 'v':
	      ch = '\v';	/* Vtab */
	      break;
	    case 'x':
	    case 'X':
	      state = st_hex;	/* Hex prefix */
	      ch = 0;
	      break;
	    case '0':
	    case '1':
	    case '2':
	    case '3':
	    case '4':
	    case '5':
	    case '6':
	    case '7':
	      state = st_oct;	/* Octal prefix */
	      ch = *p - '0';
	      break;
	    case '?':
	      if ( wildcards )
		{
		  if ( magic ) *(magic++) = (char)0; /* Ignore byte */
		  if ( mask ) *(mask++) = (char)0;
		  count++;
		  state = st_def;
		  break;
		}
	      /* else fall through */
	    default:
	      ch = *p;		/* Preserve character (e.g. " or \) */
	      break;
	    }
	  
	  p++;
	  
	  if ( state == st_backsl )
	    {
	      if ( magic ) *(magic++) = ch;
	      if ( mask ) *(mask++) = (char)(-1);
	      count++;
	      state = st_def;
	    }
	  break;

	case st_oct:
	  if ( *p >= '0' && *p <='7' )
	    {
	      ch <<= 3;
	      ch += *(p++) - '0';
	    }
	  else
	    {
	      if ( magic ) *(magic++) = ch;
	      if ( mask ) *(mask++) = (char)(-1);
	      count++;
	      state = st_def;	/* Do not advance p */
	    }
	  break;

	case st_hex:
	  if ( *p >= '0' && *p <= '9' )
	    {
	      ch <<= 4;
	      ch += *(p++) - '0';
	    }
	  else if ( *p >= 'A' && *p <= 'F' )
	    {
	      ch <<= 4;
	      ch += *(p++) - 'A' + 10;
	    }
	  else if ( *p >= 'a' && *p <= 'f' )
	    {
	      ch <<= 4;
	      ch += *(p++) - 'a' + 10;
	    }
	  else
	    {
	      if ( magic ) *(magic++) = ch;
	      if ( mask ) *(mask++) = (char)(-1);
	      count++;
	      state = st_def;	/* Do not advance p */
	    }
	  break;
	}
    }

  if (endpos) *endpos = p;
  return count;
}

/*
 * enum actions getaction(char *pos, char **cmd)
 *
 * Reads the action proposed and returns:
 *
 * ACT_CAT       ... output file raw
 * ACT_DROP      ... silently ignore
 * ACT_REJECT    ... mail user and complain
 * ACT_FILTER    ... run through once, then done
 * ACT_PIPE      ... run through command, then feed back through filter
 * ACT_ADDCR     ... \n -> \r\n, \f -> \r\f
 * ACT_PS        ... same as ADDCR, but add Ctrl-D at end
 * ACT_FFILTER   ... same as FILTER, but use a temp file
 * ACT_FPIPE     ... same as PIPE, but use a temp file
 * ACT_RFILTER   ... same as FILTER, but redirect to a different filedes
 * ACT_RPIPE     ... same as PIPE, but redirect to a different filedes
 * ACT_RFFILTER  ... R+F+FILTER
 * ACT_RFPIPE    ... R+F+PIPE
 *
 * If the command takes an argument, point cmd to it if non-NULL
 *
 * IMPORTANT: The matching algorithm is a bit simplistic.  If any action
 * is a proper prefix of any other action, the longer action must be first
 * in the list.
 */

enum actions getaction(char *pos, char **cmd)
{
  enum actions act;
  static char *act_strs[] = { "cat", "ignore", "reject", "filter",
			      "pipe", "text", "postscript",
			      "ffilter", "fpipe", "rfilter", "rpipe",
			      "rffilter", "rfpipe", NULL };
  char **act_str;
  int i;

#if DEBUG > 3
  fprintf(stderr,"getaction %s\n", pos);
#endif
  
  while ( isspace(*pos) ) pos++; /* Ignore leading whitespace */
  
  if ( ! *pos )
    return ACT_ERR;		/* Syntax error */
    
  for ( act = ACT_CAT, act_str = act_strs ; *act_str ; act++, act_str++ )
    if ( strncmp(pos, *act_str, i = strlen(*act_str)) == 0 )
      {
	pos += i;
	break;
      }
  
  if ( ! *act_str )
    {
#if DEBUG > 3
      fprintf(stderr,"No match\n");
#endif
      return ACT_ERR;		/* Unknown action */
    }
  
  if ( *pos && !isspace(*pos) )
    {
#if DEBUG > 3
      fprintf(stderr,"Garbage at end: %s\n", pos);
#endif
      return ACT_ERR;		/* Garbage after action name */
    }

  if ( cmd )
    {
      while ( isspace(*pos) ) pos++; /* Skip leading whitespace again */
      *cmd = pos;
    }
  
  return act;
}