File: ksym.c

package info (click to toggle)
sysklogd 1.4.1-17
  • links: PTS
  • area: main
  • in suites: sarge
  • size: 464 kB
  • ctags: 303
  • sloc: ansic: 3,799; sh: 354; perl: 200; makefile: 184
file content (901 lines) | stat: -rw-r--r-- 23,809 bytes parent folder | download | duplicates (3)
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
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
/*
    ksym.c - functions for kernel address->symbol translation
    Copyright (c) 1995, 1996  Dr. G.W. Wettstein <greg@wind.rmcc.com>
    Copyright (c) 1996 Enjellic Systems Development

    This file is part of the sysklogd package, a kernel and system log daemon.

    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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

/*
 * This file contains functions which handle the translation of kernel
 * numeric addresses into symbols for the klogd utility.
 *
 * Sat Oct 28 09:00:14 CDT 1995:  Dr. Wettstein
 *	Initial Version.
 *
 * Fri Nov 24 12:50:52 CST 1995:  Dr. Wettstein
 *	Added VERBOSE_DEBUGGING define to make debugging output more
 *	manageable.
 *
 *	Added support for verification of the loaded kernel symbols.  If
 *	no version information can be be found in the mapfile a warning
 *	message is issued but translation will still take place.  This
 *	will be the default case if kernel versions < 1.3.43 are used.
 *
 *	If the symbols in the mapfile are of the same version as the kernel
 *	that is running an informative message is issued.  If the symbols
 *	in the mapfile do not match the current kernel version a warning
 *	message is issued and translation is disabled.
 *
 * Wed Dec  6 16:14:11 CST 1995:  Dr. Wettstein
 *	Added /boot/System.map to the list of symbol maps to search for.
 *	Also made this map the first item in the search list.  I am open
 *	to CONSTRUCTIVE suggestions for any additions or corrections to
 *	the list of symbol maps to search for.  Be forewarned that the
 *	list in use is the consensus agreement between myself, Linus and
 *	some package distributers.  It is a given that no list will suit
 *	everyone's taste.  If you have rabid concerns about the list
 *	please feel free to edit the system_maps array and compile your
 *	own binaries.
 *
 *	Added support for searching of the list of symbol maps.  This
 *	allows support for access to multiple symbol maps.  The theory
 *	behind this is that a production kernel may have a system map in
 *	/boot/System.map.  If a test kernel is booted this system map
 *	would be skipped in favor of one found in /usr/src/linux.
 *
 * Thu Jan 18 11:18:31 CST 1996:  Dr. Wettstein
 *	Added patch from beta-testers to allow for reading of both
 *	ELF and a.out map files.
 *
 * Wed Aug 21 09:15:49 CDT 1996:  Dr. Wettstein
 *	Reloading of kernel module symbols is now turned on by the
 *	SetParanoiaLevel function.  The default behavior is to NOT reload
 *	the kernel module symbols when a protection fault is detected.
 *
 *	Added support for freeing of the current kernel module symbols.
 *	This was necessary to support reloading of the kernel module symbols.
 *
 *	When a matching static symbol table is loaded the kernel version
 *	number is printed.
 *
 * Mon Jun  9 17:12:42 CST 1997:  Martin Schulze
 *	Added #1 and #2 to some error messages in order to being able
 *	to divide them (ulmo@Q.Net)
 *
 * Fri Jun 13 10:50:23 CST 1997:  Martin Schulze
 *	Changed definition of LookupSymbol to non-static because it is
 *	used in klogd.c, too.
 *
 * Fri Jan  9 23:00:08 CET 1998: Martin Schulze <joey@infodrom.north.de>
 *	Fixed bug that caused klogd to die if there is no System.map available.
 *
 * Sun 29 Mar 18:14:07 BST 1998: Mark Simon Phillips <M.S.Phillips@nortel.co.uk>
 *	Switched to fgets() as gets() is not buffer overrun secure.
 *
 * Mon Apr 13 18:18:45 CEST 1998: Martin Schulze <joey@infodrom.north.de>
 *	Modified loop for detecting the correct system map.  Now it won't
 *	stop if a file has been found but doesn't contain the correct map.
 *	Special thanks go go Mark Simon Phillips for the hint.
 *
 * Mon Oct 12 00:42:30 CEST 1998: Martin Schulze <joey@infodrom.north.de>
 *	Modified CheckVersion()
 *	. Use shift to decode the kernel version
 *	. Compare integers of kernel version
 *	. extract major.minor.patch from utsname.release via sscanf()
 *	The reason lays in possible use of kernel flavours which
 *	modify utsname.release but no the Version_ symbol.
 *
 * Sun Feb 21 22:27:49 EST 1999: Keith Owens <kaos@ocs.com.au>
 *	Fixed bug that caused klogd to die if there is no sym_array available.
 *
 * Tue Sep 12 23:48:12 CEST 2000: Martin Schulze <joey@infodrom.ffis.de>
 *	Close symbol file in InitKsyms() when an error occurred.
 */


/* Includes. */
#include <stdlib.h>
#include <malloc.h>
#include <sys/utsname.h>
#include "klogd.h"
#include "ksyms.h"

#define VERBOSE_DEBUGGING 0


/* Variables static to this module. */
struct sym_table
{
	unsigned long value;
	char *name;
};

static int num_syms = 0;
static int i_am_paranoid = 0;
static char vstring[12];
static struct sym_table *sym_array = (struct sym_table *) 0;

static char *system_maps[] =
{
	"/boot/System.map",
	"/System.map",
#if defined(TEST)
	"./System.map",
#endif
	(char *) 0
};


#if defined(TEST)
int debugging;
#else
extern int debugging;
#endif


/* Function prototypes. */
static char * FindSymbolFile(void);
static int AddSymbol(unsigned long, char*);
static void FreeSymbols(void);
static int CheckVersion(char *);
static int CheckMapVersion(char *);


/**************************************************************************
 * Function:	InitKsyms
 *
 * Purpose:	This function is responsible for initializing and loading
 *		the data tables used by the kernel address translations.
 *
 * Arguements:	(char *) mapfile
 *
 *			mapfile:->	A pointer to a complete path
 *					specification of the file containing
 *					the kernel map to use.
 *
 * Return:	int
 *
 *		A boolean style context is returned.  The return value will
 *		be true if initialization was successful.  False if not.
 **************************************************************************/

extern int InitKsyms(mapfile)

	char *mapfile;

{
	auto char	type,
			sym[512];

	auto int version = 0;

	auto unsigned long int address;

	auto FILE *sym_file;


	/* Check and make sure that we are starting with a clean slate. */
	if ( num_syms > 0 )
		FreeSymbols();


	/*
	 * Search for and open the file containing the kernel symbols.
	 */
	if ( mapfile != (char *) 0 )
	{
		if ( (sym_file = fopen(mapfile, "r")) == (FILE *) 0 )
		{
			Syslog(LOG_WARNING, "Cannot open map file: %s.", \
			       mapfile);
			return(0);
		}
	}
	else
	{
		if ( (mapfile = FindSymbolFile()) == (char *) 0 ) 
		{
			Syslog(LOG_WARNING, "Cannot find map file.");
			if ( debugging )
				fputs("Cannot find map file.\n", stderr);
			return(0);
		}
		
		if ( (sym_file = fopen(mapfile, "r")) == (FILE *) 0 )
		{
			Syslog(LOG_WARNING, "Cannot open map file.");
			if ( debugging )
				fputs("Cannot open map file.\n", stderr);
			return(0);
		}
	}
	

	/*
	 * Read the kernel symbol table file and add entries for each
	 * line.  I suspect that the use of fscanf is not really in vogue
	 * but it was quick and dirty and IMHO suitable for fixed format
	 * data such as this.  If anybody doesn't agree with this please
	 * e-mail me a diff containing a parser with suitable political
	 * correctness -- GW.
	 */
	while ( !feof(sym_file) )
	{
		if ( fscanf(sym_file, "%lx %c %s\n", &address, &type, sym)
		    != 3 )
		{
			Syslog(LOG_ERR, "Error in symbol table input (#1).");
			fclose(sym_file);
			return(0);
		}
		if ( VERBOSE_DEBUGGING && debugging )
			fprintf(stderr, "Address: %lx, Type: %c, Symbol: %s\n",
				address, type, sym);

		if ( AddSymbol(address, sym) == 0 )
		{
			Syslog(LOG_ERR, "Error adding symbol - %s.", sym);
			fclose(sym_file);
			return(0);
		}

		if ( version == 0 )
			version = CheckVersion(sym);
	}
	

	Syslog(LOG_INFO, "Loaded %d symbols from %s.", num_syms, mapfile);
	switch ( version )
	{
	    case -1:
		Syslog(LOG_WARNING, "Symbols do not match kernel version.");
		num_syms = 0;
		break;

	    case 0:
		Syslog(LOG_WARNING, "Cannot verify that symbols match " \
		       "kernel version.");
		break;
		
	    case 1:
		Syslog(LOG_INFO, "Symbols match kernel version %s.", vstring);
		break;
	}
		
	fclose(sym_file);
	return(1);
}


/**************************************************************************
 * Function:	FindSymbolFile
 *
 * Purpose:	This function is responsible for encapsulating the search
 *		for a valid symbol file.  Encapsulating the search for
 *		the map file in this function allows an intelligent search
 *		process to be implemented.
 *
 *		The list of symbol files will be searched until either a
 *		symbol file is found whose version matches the currently
 *		executing kernel or the end of the list is encountered.  If
 *		the end of the list is encountered the first available
 *		symbol file is returned to the caller.
 *
 *		This strategy allows klogd to locate valid symbol files
 *		for both a production and an experimental kernel.  For
 *		example a map for a production kernel could be installed
 *		in /boot.  If an experimental kernel is loaded the map
 *		in /boot will be skipped and the map in /usr/src/linux would
 *		be used if its version number matches the executing kernel.
 *
 * Arguements:	None specified.
 *
 * Return:	char *
 *
 *		If a valid system map cannot be located a null pointer
 *		is returned to the caller.
 *
 *		If the search is succesful a pointer is returned to the
 *		caller which points to the name of the file containing
 *		the symbol table to be used.
 **************************************************************************/

static char * FindSymbolFile()

{
	auto char	*file = (char *) 0,
			**mf = system_maps;

	auto struct utsname utsname;
	static char symfile[100];

	auto FILE *sym_file = (FILE *) 0;

        if ( uname(&utsname) < 0 )
        {
                Syslog(LOG_ERR, "Cannot get kernel version information.");
                return(0);
        }

	if ( debugging )
		fputs("Searching for symbol map.\n", stderr);
	
	for (mf = system_maps; *mf != (char *) 0 && file == (char *) 0; ++mf)
	{
 
		sprintf (symfile, "%s-%s", *mf, utsname.release);
		if ( debugging )
			fprintf(stderr, "Trying %s.\n", symfile);
		if ( (sym_file = fopen(symfile, "r")) != (FILE *) 0 ) {
			if (CheckMapVersion(symfile) == 1)
				file = symfile;
		}
		if (sym_file == (FILE *) 0 || file == (char *) 0) {
			sprintf (symfile, "%s", *mf);
			if ( debugging )
				fprintf(stderr, "Trying %s.\n", symfile);
			if ( (sym_file = fopen(symfile, "r")) != (FILE *) 0 ) {
				if (CheckMapVersion(symfile) == 1)
					file = symfile;
			}
		}

	}

	/*
	 * At this stage of the game we are at the end of the symbol
	 * tables.
	 */
	if ( debugging )
		fprintf(stderr, "End of search list encountered.\n");
	return(file);
}


/**************************************************************************
 * Function:	CheckVersion
 *
 * Purpose:	This function is responsible for determining whether or
 *		the system map being loaded matches the version of the
 *		currently running kernel.
 *
 *		The kernel version is checked by examing a variable which
 *		is of the form:	_Version_66347 (a.out) or Version_66437 (ELF).
 *
 *		The suffix of this variable is the current kernel version
 *		of the kernel encoded in base 256.  For example the
 *		above variable would be decoded as:
 *
 *			(66347 = 1*65536 + 3*256 + 43 = 1.3.43)
 *
 *		(Insert appropriate deities here) help us if Linus ever
 *		needs more than 255 patch levels to get a kernel out the
 *		door... :-)
 *
 * Arguements:	(char *) version
 *
 *			version:->	A pointer to the string which
 *					is to be decoded as a kernel
 *					version variable.
 *
 * Return:	int
 *
 *		       -1:->	The currently running kernel version does
 *				not match this version string.
 *
 *			0:->	The string is not a kernel version variable.
 *
 *			1:->	The executing kernel is of the same version
 *				as the version string.
 **************************************************************************/

static int CheckVersion(version)

	char *version;
	

{
	auto int	vnum,
			major,
			minor,
			patch;

#ifndef TESTING
	int kvnum;
	auto struct utsname utsname;
#endif

	static char *prefix = { "Version_" };


	/* Early return if there is no hope. */
	if ( strncmp(version, prefix, strlen(prefix)) == 0  /* ELF */ ||
	   (*version == '_' &&
		strncmp(++version, prefix, strlen(prefix)) == 0 ) /* a.out */ )
		;
	else
		return(0);


	/*
	 * Since the symbol looks like a kernel version we can start
	 * things out by decoding the version string into its component
	 * parts.
	 */
	vnum = atoi(version + strlen(prefix));
	patch = vnum & 0x000000FF;
	minor = (vnum >> 8) & 0x000000FF;
	major = (vnum >> 16) & 0x000000FF;
	if ( debugging )
		fprintf(stderr, "Version string = %s, Major = %d, " \
		       "Minor = %d, Patch = %d.\n", version +
		       strlen(prefix), major, minor, \
		       patch);
	sprintf(vstring, "%d.%d.%d", major, minor, patch);

#ifndef TESTING
	/*
	 * We should now have the version string in the vstring variable in
	 * the same format that it is stored in by the kernel.  We now
	 * ask the kernel for its version information and compare the two
	 * values to determine if our system map matches the kernel
	 * version level.
	 */
	if ( uname(&utsname) < 0 )
	{
		Syslog(LOG_ERR, "Cannot get kernel version information.");
		return(0);
	}
	if ( debugging )
		fprintf(stderr, "Comparing kernel %s with symbol table %s.\n",\
		       utsname.release, vstring);

	if ( sscanf (utsname.release, "%d.%d.%d", &major, &minor, &patch) < 3 )
	{
		Syslog(LOG_ERR, "Kernel send bogus release string `%s'.",
		       utsname.release);
		return(0);
	}

	/* Compute the version code from data sent by the kernel */
	kvnum = (major << 16) | (minor << 8) | patch;

	/* Failure. */
	if ( vnum != kvnum )
		return(-1);

	/* Success. */
#endif
	return(1);
}


/**************************************************************************
 * Function:	CheckMapVersion
 *
 * Purpose:	This function is responsible for determining whether or
 *		the system map being loaded matches the version of the
 *		currently running kernel.  It uses CheckVersion as
 *		backend.
 *
 * Arguements:	(char *) fname
 *
 *			fname:->	A pointer to the string which
 *					references the system map file to
 *					be used.
 *
 * Return:	int
 *
 *		       -1:->	The currently running kernel version does
 *				not match the version in the given file.
 *
 *			0:->	No system map file or no version information.
 *
 *			1:->	The executing kernel is of the same version
 *				as the version of the map file.
 **************************************************************************/

static int CheckMapVersion(fname)

	char *fname;
	

{
	int	version;
	FILE	*sym_file;
	auto unsigned long int address;
	auto char	type,
			sym[512];

	if ( (sym_file = fopen(fname, "r")) != (FILE *) 0 ) {
		/*
		 * At this point a map file was successfully opened.  We
		 * now need to search this file and look for version
		 * information.
		 */
		Syslog(LOG_INFO, "Inspecting %s", fname);

		version = 0;
		while ( !feof(sym_file) && (version == 0) )
		{
			if ( fscanf(sym_file, "%lx %c %s\n", &address, \
				    &type, sym) != 3 )
			{
				Syslog(LOG_ERR, "Error in symbol table input (#2).");
				fclose(sym_file);
				return(0);
			}
			if ( VERBOSE_DEBUGGING && debugging )
				fprintf(stderr, "Address: %lx, Type: %c, " \
				    "Symbol: %s\n", address, type, sym);

			version = CheckVersion(sym);
		}
		fclose(sym_file);

		switch ( version )
		{
		    case -1:
			Syslog(LOG_ERR, "Symbol table has incorrect " \
				"version number.\n");
			break;
			
		    case 0:
			if ( debugging )
				fprintf(stderr, "No version information " \
					"found.\n");
			break;
		    case 1:
			if ( debugging )
				fprintf(stderr, "Found table with " \
					"matching version number.\n");
			break;
		}

		return(version);
	}

	return(0);
}

	
/**************************************************************************
 * Function:	AddSymbol
 *
 * Purpose:	This function is responsible for adding a symbol name
 *		and its address to the symbol table.
 *
 * Arguements:	(unsigned long) address, (char *) symbol
 *
 * Return:	int
 *
 *		A boolean value is assumed.  True if the addition is
 *		successful.  False if not.
 **************************************************************************/

static int AddSymbol(address, symbol)

	unsigned long address;
	
	char *symbol;
	
{
	/* Allocate the the symbol table entry. */
	sym_array = (struct sym_table *) realloc(sym_array, (num_syms+1) * \
						 sizeof(struct sym_table));
	if ( sym_array == (struct sym_table *) 0 )
		return(0);

	/* Then the space for the symbol. */
	sym_array[num_syms].name = (char *) malloc(strlen(symbol)*sizeof(char)\
						   + 1);
	if ( sym_array[num_syms].name == (char *) 0 )
		return(0);
	
	sym_array[num_syms].value = address;
	strcpy(sym_array[num_syms].name, symbol);
	++num_syms;
	return(1);
}


/**************************************************************************
 * Function:	LookupSymbol
 *
 * Purpose:	Find the symbol which is related to the given kernel
 *		address.
 *
 * Arguements:	(long int) value, (struct symbol *) sym
 *
 *		value:->	The address to be located.
 * 
 *		sym:->		A pointer to a structure which will be
 *				loaded with the symbol's parameters.
 *
 * Return:	(char *)
 *
 *		If a match cannot be found a diagnostic string is printed.
 *		If a match is found the pointer to the symbolic name most
 *		closely matching the address is returned.
 **************************************************************************/

char * LookupSymbol(value, sym)

	unsigned long value;

	struct symbol *sym;
	
{
	auto int lp;
	
	auto char *last;

	if (!sym_array)
		return((char *) 0);

	last = sym_array[0].name;
	sym->offset = 0;
	sym->size = 0;
	if ( value < sym_array[0].value )
		return((char *) 0);
	
	for(lp= 0; lp <= num_syms; ++lp)
	{
		if ( sym_array[lp].value > value )
		{		
			sym->offset = value - sym_array[lp-1].value;
			sym->size = sym_array[lp].value - \
				sym_array[lp-1].value;
			return(last);
		}
		last = sym_array[lp].name;
	}

	if ( (last = LookupModuleSymbol(value, sym)) != (char *) 0 )
		return(last);

	return((char *) 0);
}


/**************************************************************************
 * Function:	FreeSymbols
 *
 * Purpose:	This function is responsible for freeing all memory which
 *		has been allocated to hold the static symbol table.  It
 *		also initializes the symbol count and in general prepares
 *		for a re-read of a static symbol table.
 *
 * Arguements:  void
 *
 * Return:	void
 **************************************************************************/

static void FreeSymbols()

{
	auto int lp;

	/* Free each piece of memory allocated for symbol names. */
	for(lp= 0; lp < num_syms; ++lp)
		free(sym_array[lp].name);

	/* Whack the entire array and initialize everything. */
	free(sym_array);
	sym_array = (struct sym_table *) 0;
	num_syms = 0;

	return;
}


/**************************************************************************
 * Function:	LogExpanded
 *
 * Purpose:	This function is responsible for logging a kernel message
 *		line after all potential numeric kernel addresses have
 *		been resolved symolically.
 *
 * Arguements:	(char *) line, (char *) el
 *
 *		line:->	A pointer to the buffer containing the kernel
 *			message to be expanded and logged.
 *
 *		el:->	A pointer to the buffer into which the expanded
 *			kernel line will be written.
 *
 * Return:	void
 **************************************************************************/

extern char * ExpandKadds(line, el)

	char *line;

	char *el;
	
{
	auto char	dlm,
			*kp,
			*sl = line,
			*elp = el,
			*symbol;

	char num[15];
	auto unsigned long int value;

	auto struct symbol sym;


	/*
	 * This is as handy a place to put this as anyplace.
	 *
	 * Since the insertion of kernel modules can occur in a somewhat
	 * dynamic fashion we need some mechanism to insure that the
	 * kernel symbol tables get read just prior to when they are
	 * needed.
	 *
	 * To accomplish this we look for the Oops string and use its
	 * presence as a signal to load the module symbols.
	 *
	 * This is not the best solution of course, especially if the
	 * kernel is rapidly going out to lunch.  What really needs to
	 * be done is to somehow generate a callback from the
	 * kernel whenever a module is loaded or unloaded.  I am
	 * open for patches.
	 */
	if ( i_am_paranoid &&
	     (strstr(line, "Oops:") != (char *) 0) && !InitMsyms() )
		Syslog(LOG_WARNING, "Cannot load kernel module symbols.\n");
	

	/*
	 * Early return if there do not appear to be any kernel
	 * messages in this line.
	 */
	if ( (num_syms == 0) ||
	     (kp = strstr(line, "[<")) == (char *) 0 )
	{
		strcpy(el, line);
		return(el);
	}

	/* Loop through and expand all kernel messages. */
	do
	{
		while ( sl < kp+1 )
			*elp++ = *sl++;

		/* Now poised at a kernel delimiter. */
	        if ( (kp = strstr(sl, ">]")) == (char *) 0 )
		{
			strcpy(el, sl);
			return(el);
		}
		dlm = *kp;
		strncpy(num,sl+1,kp-sl-1);
		num[kp-sl-1] = '\0';
		value = strtoul(num, (char **) 0, 16);
		if ( (symbol = LookupSymbol(value, &sym)) == (char *) 0 )
			symbol = sl;
			
		strcat(elp, symbol);
		elp += strlen(symbol);
		if ( debugging )
			fprintf(stderr, "Symbol: %s = %lx = %s, %x/%d\n", \
				sl+1, value, \
				(sym.size==0) ? symbol+1 : symbol, \
				sym.offset, sym.size);

		value = 2;
		if ( sym.size != 0 )
		{
			--value;
			++kp;
			elp += sprintf(elp, "+%x/%d", sym.offset, sym.size);
		}
		strncat(elp, kp, value);
		elp += value;
		sl = kp + value;
		if ( (kp = strstr(sl, "[<")) == (char *) 0 )
			strcat(elp, sl);
	}
	while ( kp != (char *) 0);
		
	if ( debugging )
		fprintf(stderr, "Expanded line: %s\n", el);
	return(el);
}


/**************************************************************************
 * Function:	SetParanoiaLevel
 *
 * Purpose:	This function is an interface function for setting the
 *		mode of loadable module symbol lookups.  Probably overkill
 *		but it does slay another global variable.
 *
 * Arguements:	(int) level
 *
 *		level:->	The amount of paranoia which is to be
 *				present when resolving kernel exceptions.
 * Return:	void
 **************************************************************************/

extern void SetParanoiaLevel(level)

	int level;

{
	i_am_paranoid = level;
	return;
}


/*
 * Setting the -DTEST define enables the following code fragment to
 * be compiled.  This produces a small standalone program which will
 * echo the standard input of the process to stdout while translating
 * all numeric kernel addresses into their symbolic equivalent.
 */
#if defined(TEST)

#include <stdarg.h>

extern int main(int, char **);


extern int main(int argc, char *argv[])
{
	auto char line[1024], eline[2048];

	debugging = 1;
	
	
	if ( !InitKsyms((char *) 0) )
	{
		fputs("ksym: Error loading system map.\n", stderr);
		return(1);
	}

	while ( !feof(stdin) )
	{
		fgets(line, sizeof(line), stdin);
		if (line[strlen(line)-1] == '\n') line[strlen(line)-1] = '\0'; /* Trash NL char */
		memset(eline, '\0', sizeof(eline));
		ExpandKadds(line, eline);
		fprintf(stdout, "%s\n", eline);
	}
	

	return(0);
}

extern void Syslog(int priority, char *fmt, ...)

{
	va_list ap;

	va_start(ap, fmt);
	fprintf(stdout, "Pr: %d, ", priority);
	vfprintf(stdout, fmt, ap);
	va_end(ap);
	fputc('\n', stdout);

	return;
}
#endif