summaryrefslogtreecommitdiffstats
path: root/sbin/fdisk/fdisk.c
blob: 90b34036965e148b1e26c3a5e8d04424caa81069 (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
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
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
/*
 * Mach Operating System
 * Copyright (c) 1992 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/disk.h>
#include <sys/disklabel.h>
#include <sys/diskmbr.h>
#include <sys/endian.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <ctype.h>
#include <fcntl.h>
#include <err.h>
#include <errno.h>
#include <libgeom.h>
#include <paths.h>
#include <regex.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

int iotest;

#define LBUF 100
static char lbuf[LBUF];

/*
 *
 * Ported to 386bsd by Julian Elischer  Thu Oct 15 20:26:46 PDT 1992
 *
 * 14-Dec-89  Robert Baron (rvb) at Carnegie-Mellon University
 *	Copyright (c) 1989	Robert. V. Baron
 *	Created.
 */

#define Decimal(str, ans, tmp) if (decimal(str, &tmp, ans)) ans = tmp

#define RoundCyl(x) ((((x) + cylsecs - 1) / cylsecs) * cylsecs)

#define MAX_SEC_SIZE 2048	/* maximum section size that is supported */
#define MIN_SEC_SIZE 512	/* the sector size to start sensing at */
static int secsize = 0;		/* the sensed sector size */

static char *disk;

static int cyls, sectors, heads, cylsecs, disksecs;

struct mboot {
	unsigned char padding[2]; /* force the longs to be long aligned */
	unsigned char *bootinst;  /* boot code */
	off_t bootinst_size;
	struct	dos_partition parts[NDOSPART];
};

static struct mboot mboot;
static int fd;

#define ACTIVE 0x80

static uint dos_cyls;
static uint dos_heads;
static uint dos_sectors;
static uint dos_cylsecs;

#define DOSSECT(s,c) ((s & 0x3f) | ((c >> 2) & 0xc0))
#define DOSCYL(c)	(c & 0xff)

#define MAX_ARGS	10

static int	current_line_number;

static int	geom_processed = 0;
static int	part_processed = 0;
static int	active_processed = 0;

typedef struct cmd {
    char		cmd;
    int			n_args;
    struct arg {
	char	argtype;
	int	arg_val;
    }			args[MAX_ARGS];
} CMD;

static int B_flag  = 0;		/* replace boot code */
static int I_flag  = 0;		/* use entire disk for FreeBSD */
static int a_flag  = 0;		/* set active partition */
static char *b_flag = NULL;	/* path to boot code */
static int i_flag  = 0;		/* replace partition data */
static int q_flag  = 0;		/* Be quiet */
static int u_flag  = 0;		/* update partition data */
static int s_flag  = 0;		/* Print a summary and exit */
static int t_flag  = 0;		/* test only */
static char *f_flag = NULL;	/* Read config info from file */
static int v_flag  = 0;		/* Be verbose */
static int print_config_flag = 0;

static struct part_type
{
	unsigned char type;
	const char *name;
} part_types[] = {
	 {0x00, "unused"}
	,{0x01, "Primary DOS with 12 bit FAT"}
	,{0x02, "XENIX / file system"}
	,{0x03, "XENIX /usr file system"}
	,{0x04, "Primary DOS with 16 bit FAT (< 32MB)"}
	,{0x05, "Extended DOS"}
	,{0x06, "Primary 'big' DOS (>= 32MB)"}
	,{0x07, "OS/2 HPFS, NTFS, QNX-2 (16 bit) or Advanced UNIX"}
	,{0x08, "AIX file system or SplitDrive"}
	,{0x09, "AIX boot partition or Coherent"}
	,{0x0A, "OS/2 Boot Manager, OPUS or Coherent swap"}
	,{0x0B, "DOS or Windows 95 with 32 bit FAT"}
	,{0x0C, "DOS or Windows 95 with 32 bit FAT (LBA)"}
	,{0x0E, "Primary 'big' DOS (>= 32MB, LBA)"}
	,{0x0F, "Extended DOS (LBA)"}
	,{0x10, "OPUS"}
	,{0x11, "OS/2 BM: hidden DOS with 12-bit FAT"}
	,{0x12, "Compaq diagnostics"}
	,{0x14, "OS/2 BM: hidden DOS with 16-bit FAT (< 32MB)"}
	,{0x16, "OS/2 BM: hidden DOS with 16-bit FAT (>= 32MB)"}
	,{0x17, "OS/2 BM: hidden IFS (e.g. HPFS)"}
	,{0x18, "AST Windows swapfile"}
	,{0x24, "NEC DOS"}
	,{0x3C, "PartitionMagic recovery"}
	,{0x39, "plan9"}
	,{0x40, "VENIX 286"}
	,{0x41, "Linux/MINIX (sharing disk with DRDOS)"}
	,{0x42, "SFS or Linux swap (sharing disk with DRDOS)"}
	,{0x43, "Linux native (sharing disk with DRDOS)"}
	,{0x4D, "QNX 4.2 Primary"}
	,{0x4E, "QNX 4.2 Secondary"}
	,{0x4F, "QNX 4.2 Tertiary"}
	,{0x50, "DM (disk manager)"}
	,{0x51, "DM6 Aux1 (or Novell)"}
	,{0x52, "CP/M or Microport SysV/AT"}
	,{0x53, "DM6 Aux3"}
	,{0x54, "DM6"}
	,{0x55, "EZ-Drive (disk manager)"}
	,{0x56, "Golden Bow (disk manager)"}
	,{0x5c, "Priam Edisk (disk manager)"} /* according to S. Widlake */
	,{0x61, "SpeedStor"}
	,{0x63, "System V/386 (such as ISC UNIX), GNU HURD or Mach"}
	,{0x64, "Novell Netware/286 2.xx"}
	,{0x65, "Novell Netware/386 3.xx"}
	,{0x70, "DiskSecure Multi-Boot"}
	,{0x75, "PCIX"}
	,{0x77, "QNX4.x"}
	,{0x78, "QNX4.x 2nd part"}
	,{0x79, "QNX4.x 3rd part"}
	,{0x80, "Minix until 1.4a"}
	,{0x81, "Minix since 1.4b, early Linux partition or Mitac disk manager"}
	,{0x82, "Linux swap or Solaris x86"}
	,{0x83, "Linux native"}
	,{0x84, "OS/2 hidden C: drive"}
	,{0x85, "Linux extended"}
	,{0x86, "NTFS volume set??"}
	,{0x87, "NTFS volume set??"}
	,{0x93, "Amoeba file system"}
	,{0x94, "Amoeba bad block table"}
	,{0x9F, "BSD/OS"}
	,{0xA0, "Suspend to Disk"}
	,{0xA5, "FreeBSD/NetBSD/386BSD"}
	,{0xA6, "OpenBSD"}
	,{0xA7, "NeXTSTEP"}
	,{0xA9, "NetBSD"}
	,{0xAC, "IBM JFS"}
	,{0xAF, "HFS+"}
	,{0xB7, "BSDI BSD/386 file system"}
	,{0xB8, "BSDI BSD/386 swap"}
	,{0xBE, "Solaris x86 boot"}
	,{0xBF, "Solaris x86 (new)"}
	,{0xC1, "DRDOS/sec with 12-bit FAT"}
	,{0xC4, "DRDOS/sec with 16-bit FAT (< 32MB)"}
	,{0xC6, "DRDOS/sec with 16-bit FAT (>= 32MB)"}
	,{0xC7, "Syrinx"}
	,{0xDB, "CP/M, Concurrent CP/M, Concurrent DOS or CTOS"}
	,{0xE1, "DOS access or SpeedStor with 12-bit FAT extended partition"}
	,{0xE3, "DOS R/O or SpeedStor"}
	,{0xE4, "SpeedStor with 16-bit FAT extended partition < 1024 cyl."}
	,{0xEB, "BeOS file system"}
	,{0xEE, "EFI GPT"}
	,{0xEF, "EFI System Partition"}
	,{0xF1, "SpeedStor"}
	,{0xF2, "DOS 3.3+ Secondary"}
	,{0xF4, "SpeedStor large partition"}
	,{0xFE, "SpeedStor >1024 cyl. or LANstep"}
	,{0xFF, "Xenix bad blocks table"}
};

static void print_s0(int which);
static void print_part(int i);
static void init_sector0(unsigned long start);
static void init_boot(void);
static void change_part(int i);
static void print_params(void);
static void change_active(int which);
static void change_code(void);
static void get_params_to_use(void);
static char *get_rootdisk(void);
static void dos(struct dos_partition *partp);
static int open_disk(int flag);
static ssize_t read_disk(off_t sector, void *buf);
static int write_disk(off_t sector, void *buf);
static int get_params(void);
static int read_s0(void);
static int write_s0(void);
static int ok(const char *str);
static int decimal(const char *str, int *num, int deflt);
static const char *get_type(int type);
static int read_config(char *config_file);
static void reset_boot(void);
static int sanitize_partition(struct dos_partition *);
static void usage(void);

int
main(int argc, char *argv[])
{
	int	c, i;
	int	partition = -1;
	struct	dos_partition *partp;

	while ((c = getopt(argc, argv, "BIab:f:ipqstuv1234")) != -1)
		switch (c) {
		case 'B':
			B_flag = 1;
			break;
		case 'I':
			I_flag = 1;
			break;
		case 'a':
			a_flag = 1;
			break;
		case 'b':
			b_flag = optarg;
			break;
		case 'f':
			f_flag = optarg;
			break;
		case 'i':
			i_flag = 1;
			break;
		case 'p':
			print_config_flag = 1;
			break;
		case 'q':
			q_flag = 1;
			break;
		case 's':
			s_flag = 1;
			break;
		case 't':
			t_flag = 1;
			break;
		case 'u':
			u_flag = 1;
			break;
		case 'v':
			v_flag = 1;
			break;
		case '1':
		case '2':
		case '3':
		case '4':
			partition = c - '0';
			break;
		default:
			usage();
		}
	if (f_flag || i_flag)
		u_flag = 1;
	if (t_flag)
		v_flag = 1;
	argc -= optind;
	argv += optind;

	if (argc == 0) {
		disk = get_rootdisk();
	} else {
		disk = g_device_path(argv[0]);
		if (disk == NULL)
			err(1, "unable to get correct path for %s\n", argv[0]);
	}
	if (open_disk(u_flag) < 0)
		err(1, "cannot open disk %s", disk);

	/* (abu)use mboot.bootinst to probe for the sector size */
	if ((mboot.bootinst = malloc(MAX_SEC_SIZE)) == NULL)
		err(1, "cannot allocate buffer to determine disk sector size");
	if (read_disk(0, mboot.bootinst) == -1)
		errx(1, "could not detect sector size");
	free(mboot.bootinst);
	mboot.bootinst = NULL;

	if (print_config_flag) {
		if (read_s0())
			err(1, "read_s0");

		printf("# %s\n", disk);
		printf("g c%d h%d s%d\n", dos_cyls, dos_heads, dos_sectors);

		for (i = 0; i < NDOSPART; i++) {
			partp = ((struct dos_partition *)&mboot.parts) + i;

			if (partp->dp_start == 0 && partp->dp_size == 0)
				continue;

			printf("p %d 0x%02x %lu %lu\n", i + 1, partp->dp_typ,
			    (u_long)partp->dp_start, (u_long)partp->dp_size);

			/* Fill flags for the partition. */
			if (partp->dp_flag & 0x80)
				printf("a %d\n", i + 1);
		}
		exit(0);
	}
	if (s_flag) {
		if (read_s0())
			err(1, "read_s0");
		printf("%s: %d cyl %d hd %d sec\n", disk, dos_cyls, dos_heads,
		    dos_sectors);
		printf("Part  %11s %11s Type Flags\n", "Start", "Size");
		for (i = 0; i < NDOSPART; i++) {
			partp = ((struct dos_partition *) &mboot.parts) + i;
			if (partp->dp_start == 0 && partp->dp_size == 0)
				continue;
			printf("%4d: %11lu %11lu 0x%02x 0x%02x\n", i + 1,
			    (u_long) partp->dp_start,
			    (u_long) partp->dp_size, partp->dp_typ,
			    partp->dp_flag);
		}
		exit(0);
	}

	printf("******* Working on device %s *******\n",disk);

	if (I_flag) {
		read_s0();
		reset_boot();
		partp = (struct dos_partition *) (&mboot.parts[0]);
		partp->dp_typ = DOSPTYP_386BSD;
		partp->dp_flag = ACTIVE;
		partp->dp_start = dos_sectors;
		partp->dp_size = (disksecs / dos_cylsecs) * dos_cylsecs -
		    dos_sectors;
		dos(partp);
		if (v_flag)
			print_s0(-1);
		if (!t_flag)
			write_s0();
		exit(0);
	}
	if (f_flag) {
	    if (read_s0() || i_flag)
		reset_boot();
	    if (!read_config(f_flag))
		exit(1);
	    if (v_flag)
		print_s0(-1);
	    if (!t_flag)
		write_s0();
	} else {
	    if(u_flag)
		get_params_to_use();
	    else
		print_params();

	    if (read_s0())
		init_sector0(dos_sectors);

	    printf("Media sector size is %d\n", secsize);
	    printf("Warning: BIOS sector numbering starts with sector 1\n");
	    printf("Information from DOS bootblock is:\n");
	    if (partition == -1)
		for (i = 1; i <= NDOSPART; i++)
		    change_part(i);
	    else
		change_part(partition);

	    if (u_flag || a_flag)
		change_active(partition);

	    if (B_flag)
		change_code();

	    if (u_flag || a_flag || B_flag) {
		if (!t_flag) {
		    printf("\nWe haven't changed the partition table yet.  ");
		    printf("This is your last chance.\n");
		}
		print_s0(-1);
		if (!t_flag) {
		    if (ok("Should we write new partition table?"))
			write_s0();
		} else {
		    printf("\n-t flag specified -- partition table not written.\n");
		}
	    }
	}

	exit(0);
}

static void
usage()
{
	fprintf(stderr, "%s%s",
		"usage: fdisk [-BIaipqstu] [-b bootcode] [-1234] [disk]\n",
 		"       fdisk -f configfile [-itv] [disk]\n");
        exit(1);
}

static void
print_s0(int which)
{
	int	i;

	print_params();
	printf("Information from DOS bootblock is:\n");
	if (which == -1)
		for (i = 1; i <= NDOSPART; i++)
			printf("%d: ", i), print_part(i);
	else
		print_part(which);
}

static struct dos_partition mtpart;

static void
print_part(int i)
{
	struct	  dos_partition *partp;
	u_int64_t part_mb;

	partp = ((struct dos_partition *) &mboot.parts) + i - 1;

	if (!bcmp(partp, &mtpart, sizeof (struct dos_partition))) {
		printf("<UNUSED>\n");
		return;
	}
	/*
	 * Be careful not to overflow.
	 */
	part_mb = partp->dp_size;
	part_mb *= secsize;
	part_mb /= (1024 * 1024);
	printf("sysid %d (%#04x),(%s)\n", partp->dp_typ, partp->dp_typ,
	    get_type(partp->dp_typ));
	printf("    start %lu, size %lu (%ju Meg), flag %x%s\n",
		(u_long)partp->dp_start,
		(u_long)partp->dp_size, 
		(uintmax_t)part_mb,
		partp->dp_flag,
		partp->dp_flag == ACTIVE ? " (active)" : "");
	printf("\tbeg: cyl %d/ head %d/ sector %d;\n\tend: cyl %d/ head %d/ sector %d\n"
		,DPCYL(partp->dp_scyl, partp->dp_ssect)
		,partp->dp_shd
		,DPSECT(partp->dp_ssect)
		,DPCYL(partp->dp_ecyl, partp->dp_esect)
		,partp->dp_ehd
		,DPSECT(partp->dp_esect));
}


static void
init_boot(void)
{
#ifndef __ia64__
	const char *fname;
	int fdesc, n;
	struct stat sb;

	fname = b_flag ? b_flag : "/boot/mbr";
	if ((fdesc = open(fname, O_RDONLY)) == -1 ||
	    fstat(fdesc, &sb) == -1)
		err(1, "%s", fname);
	if ((mboot.bootinst_size = sb.st_size) % secsize != 0)
		errx(1, "%s: length must be a multiple of sector size", fname);
	if (mboot.bootinst != NULL)
		free(mboot.bootinst);
	if ((mboot.bootinst = malloc(mboot.bootinst_size = sb.st_size)) == NULL)
		errx(1, "%s: unable to allocate read buffer", fname);
	if ((n = read(fdesc, mboot.bootinst, mboot.bootinst_size)) == -1 ||
	    close(fdesc))
		err(1, "%s", fname);
	if (n != mboot.bootinst_size)
		errx(1, "%s: short read", fname);
#else
	if (mboot.bootinst != NULL)
		free(mboot.bootinst);
	mboot.bootinst_size = secsize;
	if ((mboot.bootinst = malloc(mboot.bootinst_size)) == NULL)
		errx(1, "unable to allocate boot block buffer");
	memset(mboot.bootinst, 0, mboot.bootinst_size);
	le16enc(&mboot.bootinst[DOSMAGICOFFSET], DOSMAGIC);
#endif
}


static void
init_sector0(unsigned long start)
{
	struct dos_partition *partp = (struct dos_partition *) (&mboot.parts[0]);

	init_boot();

	partp->dp_typ = DOSPTYP_386BSD;
	partp->dp_flag = ACTIVE;
	start = ((start + dos_sectors - 1) / dos_sectors) * dos_sectors;
	if(start == 0)
		start = dos_sectors;
	partp->dp_start = start;
	partp->dp_size = (disksecs / dos_cylsecs) * dos_cylsecs - start;

	dos(partp);
}

static void
change_part(int i)
{
	struct dos_partition *partp = ((struct dos_partition *) &mboot.parts) + i - 1;

    printf("The data for partition %d is:\n", i);
    print_part(i);

    if (u_flag && ok("Do you want to change it?")) {
	int tmp;

	if (i_flag) {
		bzero((char *)partp, sizeof (struct dos_partition));
		if (i == 1) {
			init_sector0(1);
			printf("\nThe static data for the slice 1 has been reinitialized to:\n");
			print_part(i);
		}
	}

	do {
		Decimal("sysid (165=FreeBSD)", partp->dp_typ, tmp);
		Decimal("start", partp->dp_start, tmp);
		Decimal("size", partp->dp_size, tmp);
		if (!sanitize_partition(partp)) {
			warnx("ERROR: failed to adjust; setting sysid to 0");
			partp->dp_typ = 0;
		}

		if (ok("Explicitly specify beg/end address ?"))
		{
			int	tsec,tcyl,thd;
			tcyl = DPCYL(partp->dp_scyl,partp->dp_ssect);
			thd = partp->dp_shd;
			tsec = DPSECT(partp->dp_ssect);
			Decimal("beginning cylinder", tcyl, tmp);
			Decimal("beginning head", thd, tmp);
			Decimal("beginning sector", tsec, tmp);
			partp->dp_scyl = DOSCYL(tcyl);
			partp->dp_ssect = DOSSECT(tsec,tcyl);
			partp->dp_shd = thd;

			tcyl = DPCYL(partp->dp_ecyl,partp->dp_esect);
			thd = partp->dp_ehd;
			tsec = DPSECT(partp->dp_esect);
			Decimal("ending cylinder", tcyl, tmp);
			Decimal("ending head", thd, tmp);
			Decimal("ending sector", tsec, tmp);
			partp->dp_ecyl = DOSCYL(tcyl);
			partp->dp_esect = DOSSECT(tsec,tcyl);
			partp->dp_ehd = thd;
		} else
			dos(partp);

		print_part(i);
	} while (!ok("Are we happy with this entry?"));
    }
}

static void
print_params()
{
	printf("parameters extracted from in-core disklabel are:\n");
	printf("cylinders=%d heads=%d sectors/track=%d (%d blks/cyl)\n\n"
			,cyls,heads,sectors,cylsecs);
	if (dos_cyls > 1023 || dos_heads > 255 || dos_sectors > 63)
		printf("Figures below won't work with BIOS for partitions not in cyl 1\n");
	printf("parameters to be used for BIOS calculations are:\n");
	printf("cylinders=%d heads=%d sectors/track=%d (%d blks/cyl)\n\n"
		,dos_cyls,dos_heads,dos_sectors,dos_cylsecs);
}

static void
change_active(int which)
{
	struct dos_partition *partp = &mboot.parts[0];
	int active, i, new, tmp;

	active = -1;
	for (i = 0; i < NDOSPART; i++) {
		if ((partp[i].dp_flag & ACTIVE) == 0)
			continue;
		printf("Partition %d is marked active\n", i + 1);
		if (active == -1)
			active = i + 1;
	}
	if (a_flag && which != -1)
		active = which;
	else if (active == -1)
		active = 1;

	if (!ok("Do you want to change the active partition?"))
		return;
setactive:
	do {
		new = active;
		Decimal("active partition", new, tmp);
		if (new < 1 || new > 4) {
			printf("Active partition number must be in range 1-4."
					"  Try again.\n");
			goto setactive;
		}
		active = new;
	} while (!ok("Are you happy with this choice"));
	for (i = 0; i < NDOSPART; i++)
		partp[i].dp_flag = 0;
	if (active > 0 && active <= NDOSPART)
		partp[active-1].dp_flag = ACTIVE;
}

static void
change_code()
{
	if (ok("Do you want to change the boot code?"))
		init_boot();
}

void
get_params_to_use()
{
	int	tmp;
	print_params();
	if (ok("Do you want to change our idea of what BIOS thinks ?"))
	{
		do
		{
			Decimal("BIOS's idea of #cylinders", dos_cyls, tmp);
			Decimal("BIOS's idea of #heads", dos_heads, tmp);
			Decimal("BIOS's idea of #sectors", dos_sectors, tmp);
			dos_cylsecs = dos_heads * dos_sectors;
			print_params();
		}
		while(!ok("Are you happy with this choice"));
	}
}


/***********************************************\
* Change real numbers into strange dos numbers	*
\***********************************************/
static void
dos(struct dos_partition *partp)
{
	int cy, sec;
	u_int32_t end;

	if (partp->dp_typ == 0 && partp->dp_start == 0 && partp->dp_size == 0) {
		memcpy(partp, &mtpart, sizeof(*partp));
		return;
	}

	/* Start c/h/s. */
	partp->dp_shd = partp->dp_start % dos_cylsecs / dos_sectors;
	cy = partp->dp_start / dos_cylsecs;
	sec = partp->dp_start % dos_sectors + 1;
	partp->dp_scyl = DOSCYL(cy);
	partp->dp_ssect = DOSSECT(sec, cy);

	/* End c/h/s. */
	end = partp->dp_start + partp->dp_size - 1;
	partp->dp_ehd = end % dos_cylsecs / dos_sectors;
	cy = end / dos_cylsecs;
	sec = end % dos_sectors + 1;
	partp->dp_ecyl = DOSCYL(cy);
	partp->dp_esect = DOSSECT(sec, cy);
}

static int
open_disk(int flag)
{
	int rwmode;

	/* Write mode if one of these flags are set. */
	rwmode = (a_flag || I_flag || B_flag || flag);
	fd = g_open(disk, rwmode);
	/* If the mode fails, try read-only if we didn't. */
	if (fd == -1 && errno == EPERM && rwmode)
		fd = g_open(disk, 0);
	if (fd == -1 && errno == ENXIO)
		return -2;
	if (fd == -1) {
		warnx("can't open device %s", disk);
		return -1;
	}
	if (get_params() == -1) {
		warnx("can't get disk parameters on %s", disk);
		return -1;
	}
	return fd;
}

static ssize_t
read_disk(off_t sector, void *buf)
{

	lseek(fd, (sector * 512), 0);
	if (secsize == 0)
		for (secsize = MIN_SEC_SIZE; secsize <= MAX_SEC_SIZE;
		     secsize *= 2) {
			/* try the read */
			int size = read(fd, buf, secsize);
			if (size == secsize)
				/* it worked so return */
				return secsize;
		}
	else
		return read(fd, buf, secsize);

	/* we failed to read at any of the sizes */
	return -1;
}

static int
write_disk(off_t sector, void *buf)
{
	int error;
	struct gctl_req *grq;
	const char *errmsg;
	char fbuf[BUFSIZ], *pname;
	int i, fdw;

	grq = gctl_get_handle();
	gctl_ro_param(grq, "verb", -1, "write MBR");
	gctl_ro_param(grq, "class", -1, "MBR");
	pname = g_providername(fd);
	if (pname == NULL) {
		warn("Error getting providername for %s", disk);
		return (-1);
	}
	gctl_ro_param(grq, "geom", -1, pname);
	gctl_ro_param(grq, "data", secsize, buf);
	errmsg = gctl_issue(grq);
	free(pname);
	if (errmsg == NULL) {
		gctl_free(grq);
		return(0);
	}
	if (!q_flag)	/* GEOM errors are benign, not all devices supported */
		warnx("%s", errmsg);
	gctl_free(grq);

	error = pwrite(fd, buf, secsize, (sector * 512));
	if (error == secsize)
		return (0);

	for (i = 1; i < 5; i++) {
		sprintf(fbuf, "%ss%d", disk, i);
		fdw = open(fbuf, O_RDWR, 0);
		if (fdw < 0)
			continue;
		error = ioctl(fdw, DIOCSMBR, buf);
		close(fdw);
		if (error == 0)
			return (0);
	}
	warnx("Failed to write sector zero");
	return(EINVAL);
}

static int
get_params()
{
	int error;
	u_int u;
	off_t o;

	error = ioctl(fd, DIOCGFWSECTORS, &u);
	if (error == 0)
		sectors = dos_sectors = u;
	else
		sectors = dos_sectors = 63;

	error = ioctl(fd, DIOCGFWHEADS, &u);
	if (error == 0)
		heads = dos_heads = u;
	else
		heads = dos_heads = 255;

	dos_cylsecs = cylsecs = heads * sectors;
	disksecs = cyls * heads * sectors;

	u = g_sectorsize(fd);
	if (u <= 0)
		return (-1);

	o = g_mediasize(fd);
	if (o < 0)
		return (-1);
	disksecs = o / u;
	cyls = dos_cyls = o / (u * dos_heads * dos_sectors);

	return (disksecs);
}

static int
read_s0()
{
	int i;

	mboot.bootinst_size = secsize;
	if (mboot.bootinst != NULL)
		free(mboot.bootinst);
	if ((mboot.bootinst = malloc(mboot.bootinst_size)) == NULL) {
		warnx("unable to allocate buffer to read fdisk "
		      "partition table");
		return -1;
	}
	if (read_disk(0, mboot.bootinst) == -1) {
		warnx("can't read fdisk partition table");
		return -1;
	}
	if (le16dec(&mboot.bootinst[DOSMAGICOFFSET]) != DOSMAGIC) {
		warnx("invalid fdisk partition table found");
		/* So should we initialize things */
		return -1;
	}
	for (i = 0; i < NDOSPART; i++)
		dos_partition_dec(
		    &mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
		    &mboot.parts[i]);
	return 0;
}

static int
write_s0()
{
	int	sector, i;

	if (iotest) {
		print_s0(-1);
		return 0;
	}
	for(i = 0; i < NDOSPART; i++)
		dos_partition_enc(&mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
		    &mboot.parts[i]);
	le16enc(&mboot.bootinst[DOSMAGICOFFSET], DOSMAGIC);
	for(sector = 0; sector < mboot.bootinst_size / secsize; sector++) 
		if (write_disk(sector,
			       &mboot.bootinst[sector * secsize]) == -1) {
			warn("can't write fdisk partition table");
			return -1;
		}
	return(0);
}


static int
ok(const char *str)
{
	printf("%s [n] ", str);
	fflush(stdout);
	if (fgets(lbuf, LBUF, stdin) == NULL)
		exit(1);
	lbuf[strlen(lbuf)-1] = 0;

	if (*lbuf &&
		(!strcmp(lbuf, "yes") || !strcmp(lbuf, "YES") ||
		 !strcmp(lbuf, "y") || !strcmp(lbuf, "Y")))
		return 1;
	else
		return 0;
}

static int
decimal(const char *str, int *num, int deflt)
{
	int acc = 0, c;
	char *cp;

	while (1) {
		printf("Supply a decimal value for \"%s\" [%d] ", str, deflt);
		fflush(stdout);
		if (fgets(lbuf, LBUF, stdin) == NULL)
			exit(1);
		lbuf[strlen(lbuf)-1] = 0;

		if (!*lbuf)
			return 0;

		cp = lbuf;
		while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
		if (!c)
			return 0;
		while ((c = *cp++)) {
			if (c <= '9' && c >= '0')
				acc = acc * 10 + c - '0';
			else
				break;
		}
		if (c == ' ' || c == '\t')
			while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
		if (!c) {
			*num = acc;
			return 1;
		} else
			printf("%s is an invalid decimal number.  Try again.\n",
				lbuf);
	}

}

static const char *
get_type(int type)
{
	int	numentries = (sizeof(part_types)/sizeof(struct part_type));
	int	counter = 0;
	struct	part_type *ptr = part_types;


	while(counter < numentries) {
		if(ptr->type == type)
			return(ptr->name);
		ptr++;
		counter++;
	}
	return("unknown");
}


static void
parse_config_line(char *line, CMD *command)
{
    char	*cp, *end;

    cp = line;
    while (1) {
	memset(command, 0, sizeof(*command));

	while (isspace(*cp)) ++cp;
	if (*cp == '\0' || *cp == '#')
	    break;
	command->cmd = *cp++;

	/*
	 * Parse args
	 */
	    while (1) {
	    while (isspace(*cp)) ++cp;
	    if (*cp == '#')
		break;		/* found comment */
	    if (isalpha(*cp))
		command->args[command->n_args].argtype = *cp++;
	    if (!isdigit(*cp))
		break;		/* assume end of line */
	    end = NULL;
	    command->args[command->n_args].arg_val = strtol(cp, &end, 0);
	    if (cp == end)
		break;		/* couldn't parse number */
	    cp = end;
	    command->n_args++;
	}
	break;
    }
}


static int
process_geometry(CMD *command)
{
    int		status = 1, i;

    while (1) {
	geom_processed = 1;
	    if (part_processed) {
	    warnx(
	"ERROR line %d: the geometry specification line must occur before\n\
    all partition specifications",
		    current_line_number);
	    status = 0;
	    break;
	}
	    if (command->n_args != 3) {
	    warnx("ERROR line %d: incorrect number of geometry args",
		    current_line_number);
	    status = 0;
	    break;
	}
	    dos_cyls = 0;
	    dos_heads = 0;
	    dos_sectors = 0;
	    for (i = 0; i < 3; ++i) {
		    switch (command->args[i].argtype) {
	    case 'c':
		dos_cyls = command->args[i].arg_val;
		break;
	    case 'h':
		dos_heads = command->args[i].arg_val;
		break;
	    case 's':
		dos_sectors = command->args[i].arg_val;
		break;
	    default:
		warnx(
		"ERROR line %d: unknown geometry arg type: '%c' (0x%02x)",
			current_line_number, command->args[i].argtype,
			command->args[i].argtype);
		status = 0;
		break;
	    }
	}
	if (status == 0)
	    break;

	dos_cylsecs = dos_heads * dos_sectors;

	/*
	 * Do sanity checks on parameter values
	 */
	    if (dos_cyls == 0) {
	    warnx("ERROR line %d: number of cylinders not specified",
		    current_line_number);
	    status = 0;
	}
	    if (dos_cyls > 1024) {
	    warnx(
	"WARNING line %d: number of cylinders (%d) may be out-of-range\n\
    (must be within 1-1024 for normal BIOS operation, unless the entire disk\n\
    is dedicated to FreeBSD)",
		    current_line_number, dos_cyls);
	}

	    if (dos_heads == 0) {
	    warnx("ERROR line %d: number of heads not specified",
		    current_line_number);
	    status = 0;
	    } else if (dos_heads > 256) {
	    warnx("ERROR line %d: number of heads must be within (1-256)",
		    current_line_number);
	    status = 0;
	}

	    if (dos_sectors == 0) {
	    warnx("ERROR line %d: number of sectors not specified",
		    current_line_number);
	    status = 0;
	    } else if (dos_sectors > 63) {
	    warnx("ERROR line %d: number of sectors must be within (1-63)",
		    current_line_number);
	    status = 0;
	}

	break;
    }
    return (status);
}


static int
process_partition(CMD *command)
{
    int				status = 0, partition;
    u_int32_t			prev_head_boundary, prev_cyl_boundary;
    u_int32_t			adj_size, max_end;
    struct dos_partition	*partp;

	while (1) {
	part_processed = 1;
		if (command->n_args != 4) {
	    warnx("ERROR line %d: incorrect number of partition args",
		    current_line_number);
	    break;
	}
	partition = command->args[0].arg_val;
		if (partition < 1 || partition > 4) {
	    warnx("ERROR line %d: invalid partition number %d",
		    current_line_number, partition);
	    break;
	}
	partp = ((struct dos_partition *) &mboot.parts) + partition - 1;
	bzero((char *)partp, sizeof (struct dos_partition));
	partp->dp_typ = command->args[1].arg_val;
	partp->dp_start = command->args[2].arg_val;
	partp->dp_size = command->args[3].arg_val;
	max_end = partp->dp_start + partp->dp_size;

		if (partp->dp_typ == 0) {
	    /*
	     * Get out, the partition is marked as unused.
	     */
	    /*
	     * Insure that it's unused.
	     */
	    bzero((char *)partp, sizeof (struct dos_partition));
	    status = 1;
	    break;
	}

	/*
	 * Adjust start upwards, if necessary, to fall on a head boundary.
	 */
		if (partp->dp_start % dos_sectors != 0) {
	    prev_head_boundary = partp->dp_start / dos_sectors * dos_sectors;
	    if (max_end < dos_sectors ||
			    prev_head_boundary > max_end - dos_sectors) {
		/*
		 * Can't go past end of partition
		 */
		warnx(
	"ERROR line %d: unable to adjust start of partition %d to fall on\n\
    a head boundary",
			current_line_number, partition);
		break;
	    }
	    warnx(
	"WARNING: adjusting start offset of partition %d\n\
    from %u to %u, to fall on a head boundary",
		    partition, (u_int)partp->dp_start,
		    (u_int)(prev_head_boundary + dos_sectors));
	    partp->dp_start = prev_head_boundary + dos_sectors;
	}

	/*
	 * Adjust size downwards, if necessary, to fall on a cylinder
	 * boundary.
	 */
	prev_cyl_boundary =
	    ((partp->dp_start + partp->dp_size) / dos_cylsecs) * dos_cylsecs;
	if (prev_cyl_boundary > partp->dp_start)
	    adj_size = prev_cyl_boundary - partp->dp_start;
		else {
	    warnx(
	"ERROR: could not adjust partition to start on a head boundary\n\
    and end on a cylinder boundary.");
	    return (0);
	}
		if (adj_size != partp->dp_size) {
	    warnx(
	"WARNING: adjusting size of partition %d from %u to %u\n\
    to end on a cylinder boundary",
		    partition, (u_int)partp->dp_size, (u_int)adj_size);
	    partp->dp_size = adj_size;
	}
		if (partp->dp_size == 0) {
	    warnx("ERROR line %d: size of partition %d is zero",
		    current_line_number, partition);
	    break;
	}

	dos(partp);
	status = 1;
	break;
    }
    return (status);
}


static int
process_active(CMD *command)
{
    int				status = 0, partition, i;
    struct dos_partition	*partp;

	while (1) {
	active_processed = 1;
		if (command->n_args != 1) {
	    warnx("ERROR line %d: incorrect number of active args",
		    current_line_number);
	    status = 0;
	    break;
	}
	partition = command->args[0].arg_val;
		if (partition < 1 || partition > 4) {
	    warnx("ERROR line %d: invalid partition number %d",
		    current_line_number, partition);
	    break;
	}
	/*
	 * Reset active partition
	 */
	partp = ((struct dos_partition *) &mboot.parts);
	for (i = 0; i < NDOSPART; i++)
	    partp[i].dp_flag = 0;
	partp[partition-1].dp_flag = ACTIVE;

	status = 1;
	break;
    }
    return (status);
}


static int
process_line(char *line)
{
    CMD		command;
    int		status = 1;

	while (1) {
	parse_config_line(line, &command);
		switch (command.cmd) {
	case 0:
	    /*
	     * Comment or blank line
	     */
	    break;
	case 'g':
	    /*
	     * Set geometry
	     */
	    status = process_geometry(&command);
	    break;
	case 'p':
	    status = process_partition(&command);
	    break;
	case 'a':
	    status = process_active(&command);
	    break;
	default:
	    status = 0;
	    break;
	}
	break;
    }
    return (status);
}


static int
read_config(char *config_file)
{
    FILE	*fp = NULL;
    int		status = 1;
    char	buf[1010];

	while (1) {
		if (strcmp(config_file, "-") != 0) {
	    /*
	     * We're not reading from stdin
	     */
			if ((fp = fopen(config_file, "r")) == NULL) {
		status = 0;
		break;
	    }
		} else {
	    fp = stdin;
	}
	current_line_number = 0;
		while (!feof(fp)) {
	    if (fgets(buf, sizeof(buf), fp) == NULL)
		break;
	    ++current_line_number;
	    status = process_line(buf);
	    if (status == 0)
		break;
	    }
	break;
    }
	if (fp) {
	/*
	 * It doesn't matter if we're reading from stdin, as we've reached EOF
	 */
	fclose(fp);
    }
    return (status);
}


static void
reset_boot(void)
{
    int				i;
    struct dos_partition	*partp;

    init_boot();
	for (i = 0; i < 4; ++i) {
	partp = ((struct dos_partition *) &mboot.parts) + i;
	bzero((char *)partp, sizeof (struct dos_partition));
    }
}

static int
sanitize_partition(struct dos_partition *partp)
{
    u_int32_t			prev_head_boundary, prev_cyl_boundary;
    u_int32_t			max_end, size, start;

    start = partp->dp_start;
    size = partp->dp_size;
    max_end = start + size;
    /* Only allow a zero size if the partition is being marked unused. */
    if (size == 0) {
	if (start == 0 && partp->dp_typ == 0)
	    return (1);
	warnx("ERROR: size of partition is zero");
	return (0);
    }
    /* Return if no adjustment is necessary. */
    if (start % dos_sectors == 0 && (start + size) % dos_sectors == 0)
	return (1);

    if (start == 0) {
	    warnx("WARNING: partition overlaps with partition table");
	    if (ok("Correct this automatically?"))
		    start = dos_sectors;
    }
    if (start % dos_sectors != 0)
	warnx("WARNING: partition does not start on a head boundary");
    if ((start  +size) % dos_sectors != 0)
	warnx("WARNING: partition does not end on a cylinder boundary");
    warnx("WARNING: this may confuse the BIOS or some operating systems");
    if (!ok("Correct this automatically?"))
	return (1);

    /*
     * Adjust start upwards, if necessary, to fall on a head boundary.
     */
    if (start % dos_sectors != 0) {
	prev_head_boundary = start / dos_sectors * dos_sectors;
	if (max_end < dos_sectors ||
	    prev_head_boundary >= max_end - dos_sectors) {
	    /*
	     * Can't go past end of partition
	     */
	    warnx(
    "ERROR: unable to adjust start of partition to fall on a head boundary");
	    return (0);
        }
	start = prev_head_boundary + dos_sectors;
    }

    /*
     * Adjust size downwards, if necessary, to fall on a cylinder
     * boundary.
     */
    prev_cyl_boundary = ((start + size) / dos_cylsecs) * dos_cylsecs;
    if (prev_cyl_boundary > start)
	size = prev_cyl_boundary - start;
    else {
	warnx("ERROR: could not adjust partition to start on a head boundary\n\
    and end on a cylinder boundary.");
	return (0);
    }

    /* Finally, commit any changes to partp and return. */
    if (start != partp->dp_start) {
	warnx("WARNING: adjusting start offset of partition to %u",
	    (u_int)start);
	partp->dp_start = start;
    }
    if (size != partp->dp_size) {
	warnx("WARNING: adjusting size of partition to %u", (u_int)size);
	partp->dp_size = size;
    }

    return (1);
}

/*
 * Try figuring out the root device's canonical disk name.
 * The following choices are considered:
 *   /dev/ad0s1a     => /dev/ad0
 *   /dev/da0a       => /dev/da0
 *   /dev/vinum/root => /dev/vinum/root
 */
static char *
get_rootdisk(void)
{
	struct statfs rootfs;
	regex_t re;
#define NMATCHES 2
	regmatch_t rm[NMATCHES];
	char *s;
	int rv;

	if (statfs("/", &rootfs) == -1)
		err(1, "statfs(\"/\")");

	if ((rv = regcomp(&re, "^(/dev/[a-z/]+[0-9]+)([sp][0-9]+)?[a-h]?$",
		    REG_EXTENDED)) != 0)
		errx(1, "regcomp() failed (%d)", rv);
	if ((rv = regexec(&re, rootfs.f_mntfromname, NMATCHES, rm, 0)) != 0)
		errx(1,
"mounted root fs resource doesn't match expectations (regexec returned %d)",
		    rv);
	if ((s = malloc(rm[1].rm_eo - rm[1].rm_so + 1)) == NULL)
		errx(1, "out of memory");
	memcpy(s, rootfs.f_mntfromname + rm[1].rm_so,
	    rm[1].rm_eo - rm[1].rm_so);
	s[rm[1].rm_eo - rm[1].rm_so] = 0;

	return s;
}
OpenPOWER on IntegriCloud