xref: /freebsd/sbin/fdisk/fdisk.c (revision eacee0ff7ec955b32e09515246bd97b6edcd2b0f)
1 /*
2  * Mach Operating System
3  * Copyright (c) 1992 Carnegie Mellon University
4  * All Rights Reserved.
5  *
6  * Permission to use, copy, modify and distribute this software and its
7  * documentation is hereby granted, provided that both the copyright
8  * notice and this permission notice appear in all copies of the
9  * software, derivative works or modified versions, and any portions
10  * thereof, and that both notices appear in supporting documentation.
11  *
12  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
13  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
15  *
16  * Carnegie Mellon requests users of this software to return to
17  *
18  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
19  *  School of Computer Science
20  *  Carnegie Mellon University
21  *  Pittsburgh PA 15213-3890
22  *
23  * any improvements or extensions that they make and grant Carnegie Mellon
24  * the rights to redistribute these changes.
25  */
26 
27 #ifndef lint
28 static const char rcsid[] =
29   "$FreeBSD$";
30 #endif /* not lint */
31 
32 #include <sys/disklabel.h>
33 #include <sys/param.h>
34 #include <sys/stat.h>
35 #include <sys/mount.h>
36 #include <ctype.h>
37 #include <fcntl.h>
38 #include <err.h>
39 #include <errno.h>
40 #include <paths.h>
41 #include <regex.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 
47 int iotest;
48 
49 #define LBUF 100
50 static char lbuf[LBUF];
51 
52 #define MBRSIGOFF	510
53 
54 /*
55  *
56  * Ported to 386bsd by Julian Elischer  Thu Oct 15 20:26:46 PDT 1992
57  *
58  * 14-Dec-89  Robert Baron (rvb) at Carnegie-Mellon University
59  *	Copyright (c) 1989	Robert. V. Baron
60  *	Created.
61  */
62 
63 #define Decimal(str, ans, tmp) if (decimal(str, &tmp, ans)) ans = tmp
64 #define Hex(str, ans, tmp) if (hex(str, &tmp, ans)) ans = tmp
65 #define String(str, ans, len) {char *z = ans; char **dflt = &z; if (string(str, dflt)) strncpy(ans, *dflt, len); }
66 
67 #define RoundCyl(x) ((((x) + cylsecs - 1) / cylsecs) * cylsecs)
68 
69 #define MAX_SEC_SIZE 2048	/* maximum section size that is supported */
70 #define MIN_SEC_SIZE 512	/* the sector size to start sensing at */
71 int secsize = 0;		/* the sensed sector size */
72 
73 char *disk;
74 
75 struct disklabel disklabel;		/* disk parameters */
76 
77 int cyls, sectors, heads, cylsecs, disksecs;
78 
79 struct mboot
80 {
81 	unsigned char padding[2]; /* force the longs to be long aligned */
82   	unsigned char *bootinst;  /* boot code */
83   	off_t bootinst_size;
84 	struct	dos_partition parts[4];
85 };
86 struct mboot mboot = {{0}, NULL, 0};
87 
88 #define ACTIVE 0x80
89 #define BOOT_MAGIC 0xAA55
90 
91 int dos_cyls;
92 int dos_heads;
93 int dos_sectors;
94 int dos_cylsecs;
95 
96 #define DOSSECT(s,c) ((s & 0x3f) | ((c >> 2) & 0xc0))
97 #define DOSCYL(c)	(c & 0xff)
98 static int partition = -1;
99 
100 
101 #define MAX_ARGS	10
102 
103 static int	current_line_number;
104 
105 static int	geom_processed = 0;
106 static int	part_processed = 0;
107 static int	active_processed = 0;
108 
109 
110 typedef struct cmd {
111     char		cmd;
112     int			n_args;
113     struct arg {
114 	char	argtype;
115 	int	arg_val;
116     }			args[MAX_ARGS];
117 } CMD;
118 
119 
120 static int B_flag  = 0;		/* replace boot code */
121 static int I_flag  = 0;		/* use entire disk for FreeBSD */
122 static int a_flag  = 0;		/* set active partition */
123 static char *b_flag = NULL;	/* path to boot code */
124 static int i_flag  = 0;		/* replace partition data */
125 static int u_flag  = 0;		/* update partition data */
126 static int s_flag  = 0;		/* Print a summary and exit */
127 static int t_flag  = 0;		/* test only, if f_flag is given */
128 static char *f_flag = NULL;	/* Read config info from file */
129 static int v_flag  = 0;		/* Be verbose */
130 
131 struct part_type
132 {
133  unsigned char type;
134  char *name;
135 }part_types[] =
136 {
137 	 {0x00, "unused"}
138 	,{0x01, "Primary DOS with 12 bit FAT"}
139 	,{0x02, "XENIX / filesystem"}
140 	,{0x03, "XENIX /usr filesystem"}
141 	,{0x04, "Primary DOS with 16 bit FAT (< 32MB)"}
142 	,{0x05, "Extended DOS"}
143 	,{0x06, "Primary 'big' DOS (>= 32MB)"}
144 	,{0x07, "OS/2 HPFS, NTFS, QNX-2 (16 bit) or Advanced UNIX"}
145 	,{0x08, "AIX filesystem or SplitDrive"}
146 	,{0x09, "AIX boot partition or Coherent"}
147 	,{0x0A, "OS/2 Boot Manager, OPUS or Coherent swap"}
148 	,{0x0B, "DOS or Windows 95 with 32 bit FAT"}
149 	,{0x0C, "DOS or Windows 95 with 32 bit FAT (LBA)"}
150 	,{0x0E, "Primary 'big' DOS (>= 32MB, LBA)"}
151 	,{0x0F, "Extended DOS (LBA)"}
152 	,{0x10, "OPUS"}
153 	,{0x11, "OS/2 BM: hidden DOS with 12-bit FAT"}
154 	,{0x12, "Compaq diagnostics"}
155 	,{0x14, "OS/2 BM: hidden DOS with 16-bit FAT (< 32MB)"}
156 	,{0x16, "OS/2 BM: hidden DOS with 16-bit FAT (>= 32MB)"}
157 	,{0x17, "OS/2 BM: hidden IFS (e.g. HPFS)"}
158 	,{0x18, "AST Windows swapfile"}
159 	,{0x24, "NEC DOS"}
160 	,{0x3C, "PartitionMagic recovery"}
161 	,{0x39, "plan9"}
162 	,{0x40, "VENIX 286"}
163 	,{0x41, "Linux/MINIX (sharing disk with DRDOS)"}
164 	,{0x42, "SFS or Linux swap (sharing disk with DRDOS)"}
165 	,{0x43, "Linux native (sharing disk with DRDOS)"}
166 	,{0x4D, "QNX 4.2 Primary"}
167 	,{0x4E, "QNX 4.2 Secondary"}
168 	,{0x4F, "QNX 4.2 Tertiary"}
169 	,{0x50, "DM (disk manager)"}
170 	,{0x51, "DM6 Aux1 (or Novell)"}
171 	,{0x52, "CP/M or Microport SysV/AT"}
172 	,{0x53, "DM6 Aux3"}
173 	,{0x54, "DM6"}
174 	,{0x55, "EZ-Drive (disk manager)"}
175 	,{0x56, "Golden Bow (disk manager)"}
176 	,{0x5c, "Priam Edisk (disk manager)"} /* according to S. Widlake */
177 	,{0x61, "SpeedStor"}
178 	,{0x63, "System V/386 (such as ISC UNIX), GNU HURD or Mach"}
179 	,{0x64, "Novell Netware/286 2.xx"}
180 	,{0x65, "Novell Netware/386 3.xx"}
181 	,{0x70, "DiskSecure Multi-Boot"}
182 	,{0x75, "PCIX"}
183 	,{0x77, "QNX4.x"}
184 	,{0x78, "QNX4.x 2nd part"}
185 	,{0x79, "QNX4.x 3rd part"}
186 	,{0x80, "Minix until 1.4a"}
187 	,{0x81, "Minix since 1.4b, early Linux partition or Mitac (disk manager)"}
188 	,{0x82, "Linux swap or Solaris x86"}
189 	,{0x83, "Linux native"}
190 	,{0x84, "OS/2 hidden C: drive"}
191 	,{0x85, "Linux extended"}
192 	,{0x86, "NTFS volume set??"}
193 	,{0x87, "NTFS volume set??"}
194 	,{0x93, "Amoeba filesystem"}
195 	,{0x94, "Amoeba bad block table"}
196 	,{0x9F, "BSD/OS"}
197 	,{0xA0, "Suspend to Disk"}
198 	,{0xA5, "FreeBSD/NetBSD/386BSD"}
199 	,{0xA6, "OpenBSD"}
200 	,{0xA7, "NeXTSTEP"}
201 	,{0xA9, "NetBSD"}
202 	,{0xB7, "BSDI BSD/386 filesystem"}
203 	,{0xB8, "BSDI BSD/386 swap"}
204 	,{0xC1, "DRDOS/sec with 12-bit FAT"}
205 	,{0xC4, "DRDOS/sec with 16-bit FAT (< 32MB)"}
206 	,{0xC6, "DRDOS/sec with 16-bit FAT (>= 32MB)"}
207 	,{0xC7, "Syrinx"}
208 	,{0xDB, "CP/M, Concurrent CP/M, Concurrent DOS or CTOS"}
209 	,{0xE1, "DOS access or SpeedStor with 12-bit FAT extended partition"}
210 	,{0xE3, "DOS R/O or SpeedStor"}
211 	,{0xE4, "SpeedStor with 16-bit FAT extended partition < 1024 cyl."}
212 	,{0xEB, "BeOS filesystem"}
213 	,{0xEE, "EFI GPT"}
214 	,{0xEF, "EFI System Partition"}
215 	,{0xF1, "SpeedStor"}
216 	,{0xF2, "DOS 3.3+ Secondary"}
217 	,{0xF4, "SpeedStor large partition"}
218 	,{0xFE, "SpeedStor >1024 cyl. or LANstep"}
219 	,{0xFF, "Xenix bad blocks table"}
220 };
221 
222 static void print_s0(int which);
223 static void print_part(int i);
224 static void init_sector0(unsigned long start);
225 static void init_boot(void);
226 static void change_part(int i);
227 static void print_params();
228 static void change_active(int which);
229 static void change_code();
230 static void get_params_to_use();
231 static char *get_rootdisk(void);
232 static void dos(struct dos_partition *partp);
233 static int open_disk(int u_flag);
234 static ssize_t read_disk(off_t sector, void *buf);
235 static ssize_t write_disk(off_t sector, void *buf);
236 static int get_params();
237 static int read_s0();
238 static int write_s0();
239 static int ok(char *str);
240 static int decimal(char *str, int *num, int deflt);
241 static char *get_type(int type);
242 static int read_config(char *config_file);
243 static void reset_boot(void);
244 static int sanitize_partition(struct dos_partition *);
245 static void usage(void);
246 #if 0
247 static int hex(char *str, int *num, int deflt);
248 static int string(char *str, char **ans);
249 #endif
250 
251 
252 int
253 main(int argc, char *argv[])
254 {
255 	struct	stat sb;
256 	int	c, i;
257 
258 	while ((c = getopt(argc, argv, "BIab:f:istuv1234")) != -1)
259 		switch (c) {
260 		case 'B':
261 			B_flag = 1;
262 			break;
263 		case 'I':
264 			I_flag = 1;
265 			break;
266 		case 'a':
267 			a_flag = 1;
268 			break;
269 		case 'b':
270 			b_flag = optarg;
271 			break;
272 		case 'f':
273 			f_flag = optarg;
274 			break;
275 		case 'i':
276 			i_flag = 1;
277 			break;
278 		case 's':
279 			s_flag = 1;
280 			break;
281 		case 't':
282 			t_flag = 1;
283 			break;
284 		case 'u':
285 			u_flag = 1;
286 			break;
287 		case 'v':
288 			v_flag = 1;
289 			break;
290 		case '1':
291 		case '2':
292 		case '3':
293 		case '4':
294 			partition = c - '0';
295 			break;
296 		default:
297 			usage();
298 		}
299 	if (f_flag || i_flag)
300 		u_flag = 1;
301 	if (t_flag)
302 		v_flag = 1;
303 	argc -= optind;
304 	argv += optind;
305 
306 	if (argc == 0) {
307 		disk = get_rootdisk();
308 	} else {
309 		if (stat(argv[0], &sb) == 0) {
310 			/* OK, full pathname given */
311 			disk = argv[0];
312 		} else if (errno == ENOENT) {
313 			/* Try prepending "/dev" */
314 			if ((disk = malloc(strlen(argv[0]) + strlen(_PATH_DEV) +
315 			     1)) == NULL)
316 				errx(1, "out of memory");
317 			strcpy(disk, _PATH_DEV);
318 			strcat(disk, argv[0]);
319 		} else {
320 			/* other stat error, let it fail below */
321 			disk = argv[0];
322 		}
323 	}
324 	if (open_disk(u_flag) < 0)
325 		err(1, "cannot open disk %s", disk);
326 
327 	/* (abu)use mboot.bootinst to probe for the sector size */
328 	if ((mboot.bootinst = malloc(MAX_SEC_SIZE)) == NULL)
329 		err(1, "cannot allocate buffer to determine disk sector size");
330 	read_disk(0, mboot.bootinst);
331 	free(mboot.bootinst);
332 	mboot.bootinst = NULL;
333 
334 	if (s_flag)
335 	{
336 		int i;
337 		struct dos_partition *partp;
338 
339 		if (read_s0())
340 			err(1, "read_s0");
341 		printf("%s: %d cyl %d hd %d sec\n", disk, dos_cyls, dos_heads,
342 		    dos_sectors);
343 		printf("Part  %11s %11s Type Flags\n", "Start", "Size");
344 		for (i = 0; i < NDOSPART; i++) {
345 			partp = ((struct dos_partition *) &mboot.parts) + i;
346 			if (partp->dp_start == 0 && partp->dp_size == 0)
347 				continue;
348 			printf("%4d: %11lu %11lu 0x%02x 0x%02x\n", i + 1,
349 			    (u_long) partp->dp_start,
350 			    (u_long) partp->dp_size, partp->dp_typ,
351 			    partp->dp_flag);
352 		}
353 		exit(0);
354 	}
355 
356 	printf("******* Working on device %s *******\n",disk);
357 
358 	if (I_flag)
359 	{
360 		struct dos_partition *partp;
361 
362 		read_s0();
363 		reset_boot();
364 		partp = (struct dos_partition *) (&mboot.parts[0]);
365 		partp->dp_typ = DOSPTYP_386BSD;
366 		partp->dp_flag = ACTIVE;
367 		partp->dp_start = dos_sectors;
368 		partp->dp_size = (disksecs / dos_cylsecs) * dos_cylsecs -
369 		    dos_sectors;
370 
371 		dos(partp);
372 		if (v_flag)
373 			print_s0(-1);
374 		write_s0();
375 		exit(0);
376 	}
377 	if (f_flag)
378 	{
379 	    if (read_s0() || i_flag)
380 	    {
381 		reset_boot();
382 	    }
383 
384 	    if (!read_config(f_flag))
385 	    {
386 		exit(1);
387 	    }
388 	    if (v_flag)
389 	    {
390 		print_s0(-1);
391 	    }
392 	    if (!t_flag)
393 	    {
394 		write_s0();
395 	    }
396 	}
397 	else
398 	{
399 	    if(u_flag)
400 	    {
401 		get_params_to_use();
402 	    }
403 	    else
404 	    {
405 		print_params();
406 	    }
407 
408 	    if (read_s0())
409 		init_sector0(dos_sectors);
410 
411 	    printf("Media sector size is %d\n", secsize);
412 	    printf("Warning: BIOS sector numbering starts with sector 1\n");
413 	    printf("Information from DOS bootblock is:\n");
414 	    if (partition == -1)
415 		for (i = 1; i <= NDOSPART; i++)
416 		    change_part(i);
417 	    else
418 		change_part(partition);
419 
420 	    if (u_flag || a_flag)
421 		change_active(partition);
422 
423 	    if (B_flag)
424 		change_code();
425 
426 	    if (u_flag || a_flag || B_flag) {
427 		if (!t_flag)
428 		{
429 		    printf("\nWe haven't changed the partition table yet.  ");
430 		    printf("This is your last chance.\n");
431 		}
432 		print_s0(-1);
433 		if (!t_flag)
434 		{
435 		    if (ok("Should we write new partition table?"))
436 			write_s0();
437 		}
438 		else
439 		{
440 		    printf("\n-t flag specified -- partition table not written.\n");
441 		}
442 	    }
443 	}
444 
445 	exit(0);
446 }
447 
448 static void
449 usage()
450 {
451 	fprintf(stderr, "%s%s",
452 		"usage: fdisk [-BIaistu] [-b bootcode] [-1234] [disk]\n",
453  		"       fdisk -f configfile [-itv] [disk]\n");
454         exit(1);
455 }
456 
457 static void
458 print_s0(int which)
459 {
460 int	i;
461 
462 	print_params();
463 	printf("Information from DOS bootblock is:\n");
464 	if (which == -1)
465 		for (i = 1; i <= NDOSPART; i++)
466 			printf("%d: ", i), print_part(i);
467 	else
468 		print_part(which);
469 }
470 
471 static struct dos_partition mtpart = { 0 };
472 
473 static void
474 print_part(int i)
475 {
476 	struct	  dos_partition *partp;
477 	u_int64_t part_mb;
478 
479 	partp = ((struct dos_partition *) &mboot.parts) + i - 1;
480 
481 	if (!bcmp(partp, &mtpart, sizeof (struct dos_partition))) {
482 		printf("<UNUSED>\n");
483 		return;
484 	}
485 	/*
486 	 * Be careful not to overflow.
487 	 */
488 	part_mb = partp->dp_size;
489 	part_mb *= secsize;
490 	part_mb /= (1024 * 1024);
491 	printf("sysid %d (%#04x),(%s)\n", partp->dp_typ, partp->dp_typ,
492 	    get_type(partp->dp_typ));
493 	printf("    start %lu, size %lu (%qd Meg), flag %x%s\n",
494 		(u_long)partp->dp_start,
495 		(u_long)partp->dp_size,
496 		part_mb,
497 		partp->dp_flag,
498 		partp->dp_flag == ACTIVE ? " (active)" : "");
499 	printf("\tbeg: cyl %d/ head %d/ sector %d;\n\tend: cyl %d/ head %d/ sector %d\n"
500 		,DPCYL(partp->dp_scyl, partp->dp_ssect)
501 		,partp->dp_shd
502 		,DPSECT(partp->dp_ssect)
503 		,DPCYL(partp->dp_ecyl, partp->dp_esect)
504 		,partp->dp_ehd
505 		,DPSECT(partp->dp_esect));
506 }
507 
508 
509 static void
510 init_boot(void)
511 {
512 	const char *fname;
513 	int fd, n;
514 	struct stat sb;
515 
516 	fname = b_flag ? b_flag : "/boot/mbr";
517 	if ((fd = open(fname, O_RDONLY)) == -1 ||
518 	    fstat(fd, &sb) == -1)
519 		err(1, "%s", fname);
520 	if ((mboot.bootinst_size = sb.st_size) % secsize != 0)
521 		errx(1, "%s: length must be a multiple of sector size", fname);
522 	if (mboot.bootinst != NULL)
523 		free(mboot.bootinst);
524 	if ((mboot.bootinst = malloc(mboot.bootinst_size = sb.st_size)) == NULL)
525 		errx(1, "%s: unable to allocate read buffer", fname);
526 	if ((n = read(fd, mboot.bootinst, mboot.bootinst_size)) == -1 ||
527 	    close(fd))
528 		err(1, "%s", fname);
529 	if (n != mboot.bootinst_size)
530 		errx(1, "%s: short read", fname);
531 }
532 
533 
534 static void
535 init_sector0(unsigned long start)
536 {
537 struct dos_partition *partp = (struct dos_partition *) (&mboot.parts[3]);
538 
539 	init_boot();
540 
541 	partp->dp_typ = DOSPTYP_386BSD;
542 	partp->dp_flag = ACTIVE;
543 	start = ((start + dos_sectors - 1) / dos_sectors) * dos_sectors;
544 	if(start == 0)
545 		start = dos_sectors;
546 	partp->dp_start = start;
547 	partp->dp_size = (disksecs / dos_cylsecs) * dos_cylsecs - start;
548 
549 	dos(partp);
550 }
551 
552 static void
553 change_part(int i)
554 {
555 struct dos_partition *partp = ((struct dos_partition *) &mboot.parts) + i - 1;
556 
557     printf("The data for partition %d is:\n", i);
558     print_part(i);
559 
560     if (u_flag && ok("Do you want to change it?")) {
561 	int tmp;
562 
563 	if (i_flag) {
564 		bzero((char *)partp, sizeof (struct dos_partition));
565 		if (i == 4) {
566 			init_sector0(1);
567 			printf("\nThe static data for the DOS partition 4 has been reinitialized to:\n");
568 			print_part(i);
569 		}
570 	}
571 
572 	do {
573 		Decimal("sysid (165=FreeBSD)", partp->dp_typ, tmp);
574 		Decimal("start", partp->dp_start, tmp);
575 		Decimal("size", partp->dp_size, tmp);
576 		if (!sanitize_partition(partp)) {
577 			warnx("ERROR: failed to adjust; setting sysid to 0");
578 			partp->dp_typ = 0;
579 		}
580 
581 		if (ok("Explicitly specify beg/end address ?"))
582 		{
583 			int	tsec,tcyl,thd;
584 			tcyl = DPCYL(partp->dp_scyl,partp->dp_ssect);
585 			thd = partp->dp_shd;
586 			tsec = DPSECT(partp->dp_ssect);
587 			Decimal("beginning cylinder", tcyl, tmp);
588 			Decimal("beginning head", thd, tmp);
589 			Decimal("beginning sector", tsec, tmp);
590 			partp->dp_scyl = DOSCYL(tcyl);
591 			partp->dp_ssect = DOSSECT(tsec,tcyl);
592 			partp->dp_shd = thd;
593 
594 			tcyl = DPCYL(partp->dp_ecyl,partp->dp_esect);
595 			thd = partp->dp_ehd;
596 			tsec = DPSECT(partp->dp_esect);
597 			Decimal("ending cylinder", tcyl, tmp);
598 			Decimal("ending head", thd, tmp);
599 			Decimal("ending sector", tsec, tmp);
600 			partp->dp_ecyl = DOSCYL(tcyl);
601 			partp->dp_esect = DOSSECT(tsec,tcyl);
602 			partp->dp_ehd = thd;
603 		} else
604 			dos(partp);
605 
606 		print_part(i);
607 	} while (!ok("Are we happy with this entry?"));
608     }
609 }
610 
611 static void
612 print_params()
613 {
614 	printf("parameters extracted from in-core disklabel are:\n");
615 	printf("cylinders=%d heads=%d sectors/track=%d (%d blks/cyl)\n\n"
616 			,cyls,heads,sectors,cylsecs);
617 	if((dos_sectors > 63) || (dos_cyls > 1023) || (dos_heads > 255))
618 		printf("Figures below won't work with BIOS for partitions not in cyl 1\n");
619 	printf("parameters to be used for BIOS calculations are:\n");
620 	printf("cylinders=%d heads=%d sectors/track=%d (%d blks/cyl)\n\n"
621 		,dos_cyls,dos_heads,dos_sectors,dos_cylsecs);
622 }
623 
624 static void
625 change_active(int which)
626 {
627 	struct dos_partition *partp = &mboot.parts[0];
628 	int active, i, new, tmp;
629 
630 	active = -1;
631 	for (i = 0; i < NDOSPART; i++) {
632 		if ((partp[i].dp_flag & ACTIVE) == 0)
633 			continue;
634 		printf("Partition %d is marked active\n", i + 1);
635 		if (active == -1)
636 			active = i + 1;
637 	}
638 	if (a_flag && which != -1)
639 		active = which;
640 	else if (active == -1)
641 		active = 1;
642 
643 	if (!ok("Do you want to change the active partition?"))
644 		return;
645 setactive:
646 	do {
647 		new = active;
648 		Decimal("active partition", new, tmp);
649 		if (new < 1 || new > 4) {
650 			printf("Active partition number must be in range 1-4."
651 					"  Try again.\n");
652 			goto setactive;
653 		}
654 		active = new;
655 	} while (!ok("Are you happy with this choice"));
656 	for (i = 0; i < NDOSPART; i++)
657 		partp[i].dp_flag = 0;
658 	if (active > 0 && active <= NDOSPART)
659 		partp[active-1].dp_flag = ACTIVE;
660 }
661 
662 static void
663 change_code()
664 {
665 	if (ok("Do you want to change the boot code?"))
666 		init_boot();
667 }
668 
669 void
670 get_params_to_use()
671 {
672 	int	tmp;
673 	print_params();
674 	if (ok("Do you want to change our idea of what BIOS thinks ?"))
675 	{
676 		do
677 		{
678 			Decimal("BIOS's idea of #cylinders", dos_cyls, tmp);
679 			Decimal("BIOS's idea of #heads", dos_heads, tmp);
680 			Decimal("BIOS's idea of #sectors", dos_sectors, tmp);
681 			dos_cylsecs = dos_heads * dos_sectors;
682 			print_params();
683 		}
684 		while(!ok("Are you happy with this choice"));
685 	}
686 }
687 
688 
689 /***********************************************\
690 * Change real numbers into strange dos numbers	*
691 \***********************************************/
692 static void
693 dos(partp)
694 	struct dos_partition *partp;
695 {
696 	int cy, sec;
697 	u_int32_t end;
698 
699 	if (partp->dp_typ == 0 && partp->dp_start == 0 && partp->dp_size == 0) {
700 		memcpy(partp, &mtpart, sizeof(*partp));
701 		return;
702 	}
703 
704 	/* Start c/h/s. */
705 	partp->dp_shd = partp->dp_start % dos_cylsecs / dos_sectors;
706 	cy = partp->dp_start / dos_cylsecs;
707 	sec = partp->dp_start % dos_sectors + 1;
708 	partp->dp_scyl = DOSCYL(cy);
709 	partp->dp_ssect = DOSSECT(sec, cy);
710 
711 	/* End c/h/s. */
712 	end = partp->dp_start + partp->dp_size - 1;
713 	partp->dp_ehd = end % dos_cylsecs / dos_sectors;
714 	cy = end / dos_cylsecs;
715 	sec = end % dos_sectors + 1;
716 	partp->dp_ecyl = DOSCYL(cy);
717 	partp->dp_esect = DOSSECT(sec, cy);
718 }
719 
720 int fd;
721 
722 	/* Getting device status */
723 
724 static int
725 open_disk(int u_flag)
726 {
727 	struct stat 	st;
728 
729 	if (stat(disk, &st) == -1) {
730 		if (errno == ENOENT)
731 			return -2;
732 		warnx("can't get file status of %s", disk);
733 		return -1;
734 	}
735 	if ( !(st.st_mode & S_IFCHR) )
736 		warnx("device %s is not character special", disk);
737 	if ((fd = open(disk,
738 	    a_flag || I_flag || B_flag || u_flag ? O_RDWR : O_RDONLY)) == -1) {
739 		if(errno == ENXIO)
740 			return -2;
741 		warnx("can't open device %s", disk);
742 		return -1;
743 	}
744 	if (get_params(0) == -1) {
745 		warnx("can't get disk parameters on %s", disk);
746 		return -1;
747 	}
748 	return fd;
749 }
750 
751 static ssize_t
752 read_disk(off_t sector, void *buf)
753 {
754 	lseek(fd,(sector * 512), 0);
755 	if( secsize == 0 )
756 		for( secsize = MIN_SEC_SIZE; secsize <= MAX_SEC_SIZE; secsize *= 2 )
757 			{
758 			/* try the read */
759 			int size = read(fd, buf, secsize);
760 			if( size == secsize )
761 				/* it worked so return */
762 				return secsize;
763 			}
764 	else
765 		return read( fd, buf, secsize );
766 
767 	/* we failed to read at any of the sizes */
768 	return -1;
769 }
770 
771 static ssize_t
772 write_disk(off_t sector, void *buf)
773 {
774 	lseek(fd,(sector * 512), 0);
775 	/* write out in the size that the read_disk found worked */
776 	return write(fd, buf, secsize);
777 }
778 
779 static int
780 get_params()
781 {
782 
783     if (ioctl(fd, DIOCGDINFO, &disklabel) == -1) {
784 	warnx("can't get disk parameters on %s; supplying dummy ones", disk);
785 	dos_cyls = cyls = 1;
786 	dos_heads = heads = 1;
787 	dos_sectors = sectors = 1;
788 	dos_cylsecs = cylsecs = heads * sectors;
789 	disksecs = cyls * heads * sectors;
790 	return disksecs;
791     }
792 
793     dos_cyls = cyls = disklabel.d_ncylinders;
794     dos_heads = heads = disklabel.d_ntracks;
795     dos_sectors = sectors = disklabel.d_nsectors;
796     dos_cylsecs = cylsecs = heads * sectors;
797     disksecs = cyls * heads * sectors;
798 
799     return (disksecs);
800 }
801 
802 
803 static int
804 read_s0()
805 {
806 	mboot.bootinst_size = secsize;
807 	if (mboot.bootinst != NULL)
808 		free(mboot.bootinst);
809 	if ((mboot.bootinst = malloc(mboot.bootinst_size)) == NULL) {
810 		warnx("unable to allocate buffer to read fdisk "
811 		      "partition table");
812 		return -1;
813 	}
814 	if (read_disk(0, mboot.bootinst) == -1) {
815 		warnx("can't read fdisk partition table");
816 		return -1;
817 	}
818 	if (*(uint16_t *)&mboot.bootinst[MBRSIGOFF] != BOOT_MAGIC) {
819 		warnx("invalid fdisk partition table found");
820 		/* So should we initialize things */
821 		return -1;
822 	}
823 	memcpy(mboot.parts, &mboot.bootinst[DOSPARTOFF], sizeof(mboot.parts));
824 	return 0;
825 }
826 
827 static int
828 write_s0()
829 {
830 #ifdef NOT_NOW
831 	int	flag;
832 #endif
833 	int	sector;
834 
835 	if (iotest) {
836 		print_s0(-1);
837 		return 0;
838 	}
839 	memcpy(&mboot.bootinst[DOSPARTOFF], mboot.parts, sizeof(mboot.parts));
840 	/*
841 	 * write enable label sector before write (if necessary),
842 	 * disable after writing.
843 	 * needed if the disklabel protected area also protects
844 	 * sector 0. (e.g. empty disk)
845 	 */
846 #ifdef NOT_NOW
847 	flag = 1;
848 	if (ioctl(fd, DIOCWLABEL, &flag) < 0)
849 		warn("ioctl DIOCWLABEL");
850 #endif
851 	for(sector = 0; sector < mboot.bootinst_size / secsize; sector++)
852 		if (write_disk(sector,
853 			       &mboot.bootinst[sector * secsize]) == -1) {
854 			warn("can't write fdisk partition table");
855 			return -1;
856 #ifdef NOT_NOW
857 			flag = 0;
858 			(void) ioctl(fd, DIOCWLABEL, &flag);
859 #endif
860 		}
861 #ifdef NOT_NOW
862 	flag = 0;
863 	(void) ioctl(fd, DIOCWLABEL, &flag);
864 #endif
865 	return(0);
866 }
867 
868 
869 static int
870 ok(str)
871 char *str;
872 {
873 	printf("%s [n] ", str);
874 	fflush(stdout);
875 	if (fgets(lbuf, LBUF, stdin) == NULL)
876 		exit(1);
877 	lbuf[strlen(lbuf)-1] = 0;
878 
879 	if (*lbuf &&
880 		(!strcmp(lbuf, "yes") || !strcmp(lbuf, "YES") ||
881 		 !strcmp(lbuf, "y") || !strcmp(lbuf, "Y")))
882 		return 1;
883 	else
884 		return 0;
885 }
886 
887 static int
888 decimal(char *str, int *num, int deflt)
889 {
890 int acc = 0, c;
891 char *cp;
892 
893 	while (1) {
894 		printf("Supply a decimal value for \"%s\" [%d] ", str, deflt);
895 		fflush(stdout);
896 		if (fgets(lbuf, LBUF, stdin) == NULL)
897 			exit(1);
898 		lbuf[strlen(lbuf)-1] = 0;
899 
900 		if (!*lbuf)
901 			return 0;
902 
903 		cp = lbuf;
904 		while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
905 		if (!c)
906 			return 0;
907 		while ((c = *cp++)) {
908 			if (c <= '9' && c >= '0')
909 				acc = acc * 10 + c - '0';
910 			else
911 				break;
912 		}
913 		if (c == ' ' || c == '\t')
914 			while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
915 		if (!c) {
916 			*num = acc;
917 			return 1;
918 		} else
919 			printf("%s is an invalid decimal number.  Try again.\n",
920 				lbuf);
921 	}
922 
923 }
924 
925 #if 0
926 static int
927 hex(char *str, int *num, int deflt)
928 {
929 int acc = 0, c;
930 char *cp;
931 
932 	while (1) {
933 		printf("Supply a hex value for \"%s\" [%x] ", str, deflt);
934 		fgets(lbuf, LBUF, stdin);
935 		lbuf[strlen(lbuf)-1] = 0;
936 
937 		if (!*lbuf)
938 			return 0;
939 
940 		cp = lbuf;
941 		while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
942 		if (!c)
943 			return 0;
944 		while ((c = *cp++)) {
945 			if (c <= '9' && c >= '0')
946 				acc = (acc << 4) + c - '0';
947 			else if (c <= 'f' && c >= 'a')
948 				acc = (acc << 4) + c - 'a' + 10;
949 			else if (c <= 'F' && c >= 'A')
950 				acc = (acc << 4) + c - 'A' + 10;
951 			else
952 				break;
953 		}
954 		if (c == ' ' || c == '\t')
955 			while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
956 		if (!c) {
957 			*num = acc;
958 			return 1;
959 		} else
960 			printf("%s is an invalid hex number.  Try again.\n",
961 				lbuf);
962 	}
963 
964 }
965 
966 static int
967 string(char *str, char **ans)
968 {
969 int c;
970 char *cp = lbuf;
971 
972 	while (1) {
973 		printf("Supply a string value for \"%s\" [%s] ", str, *ans);
974 		fgets(lbuf, LBUF, stdin);
975 		lbuf[strlen(lbuf)-1] = 0;
976 
977 		if (!*lbuf)
978 			return 0;
979 
980 		while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
981 		if (c == '"') {
982 			c = *++cp;
983 			*ans = cp;
984 			while ((c = *cp) && c != '"') cp++;
985 		} else {
986 			*ans = cp;
987 			while ((c = *cp) && c != ' ' && c != '\t') cp++;
988 		}
989 
990 		if (c)
991 			*cp = 0;
992 		return 1;
993 	}
994 }
995 #endif
996 
997 static char *
998 get_type(int type)
999 {
1000 	int	numentries = (sizeof(part_types)/sizeof(struct part_type));
1001 	int	counter = 0;
1002 	struct	part_type *ptr = part_types;
1003 
1004 
1005 	while(counter < numentries)
1006 	{
1007 		if(ptr->type == type)
1008 		{
1009 			return(ptr->name);
1010 		}
1011 		ptr++;
1012 		counter++;
1013 	}
1014 	return("unknown");
1015 }
1016 
1017 
1018 static void
1019 parse_config_line(line, command)
1020     char	*line;
1021     CMD		*command;
1022 {
1023     char	*cp, *end;
1024 
1025     cp = line;
1026     while (1)	/* dirty trick used to insure one exit point for this
1027 		   function */
1028     {
1029 	memset(command, 0, sizeof(*command));
1030 
1031 	while (isspace(*cp)) ++cp;
1032 	if (*cp == '\0' || *cp == '#')
1033 	{
1034 	    break;
1035 	}
1036 	command->cmd = *cp++;
1037 
1038 	/*
1039 	 * Parse args
1040 	 */
1041 	while (1)
1042 	{
1043 	    while (isspace(*cp)) ++cp;
1044 	    if (*cp == '#')
1045 	    {
1046 		break;		/* found comment */
1047 	    }
1048 	    if (isalpha(*cp))
1049 	    {
1050 		command->args[command->n_args].argtype = *cp++;
1051 	    }
1052 	    if (!isdigit(*cp))
1053 	    {
1054 		break;		/* assume end of line */
1055 	    }
1056 	    end = NULL;
1057 	    command->args[command->n_args].arg_val = strtol(cp, &end, 0);
1058 	    if (cp == end)
1059 	    {
1060 		break;		/* couldn't parse number */
1061 	    }
1062 	    cp = end;
1063 	    command->n_args++;
1064 	}
1065 	break;
1066     }
1067 }
1068 
1069 
1070 static int
1071 process_geometry(command)
1072     CMD		*command;
1073 {
1074     int		status = 1, i;
1075 
1076     while (1)
1077     {
1078 	geom_processed = 1;
1079 	if (part_processed)
1080 	{
1081 	    warnx(
1082 	"ERROR line %d: the geometry specification line must occur before\n\
1083     all partition specifications",
1084 		    current_line_number);
1085 	    status = 0;
1086 	    break;
1087 	}
1088 	if (command->n_args != 3)
1089 	{
1090 	    warnx("ERROR line %d: incorrect number of geometry args",
1091 		    current_line_number);
1092 	    status = 0;
1093 	    break;
1094 	}
1095 	dos_cyls = -1;
1096 	dos_heads = -1;
1097 	dos_sectors = -1;
1098 	for (i = 0; i < 3; ++i)
1099 	{
1100 	    switch (command->args[i].argtype)
1101 	    {
1102 	    case 'c':
1103 		dos_cyls = command->args[i].arg_val;
1104 		break;
1105 	    case 'h':
1106 		dos_heads = command->args[i].arg_val;
1107 		break;
1108 	    case 's':
1109 		dos_sectors = command->args[i].arg_val;
1110 		break;
1111 	    default:
1112 		warnx(
1113 		"ERROR line %d: unknown geometry arg type: '%c' (0x%02x)",
1114 			current_line_number, command->args[i].argtype,
1115 			command->args[i].argtype);
1116 		status = 0;
1117 		break;
1118 	    }
1119 	}
1120 	if (status == 0)
1121 	{
1122 	    break;
1123 	}
1124 
1125 	dos_cylsecs = dos_heads * dos_sectors;
1126 
1127 	/*
1128 	 * Do sanity checks on parameter values
1129 	 */
1130 	if (dos_cyls < 0)
1131 	{
1132 	    warnx("ERROR line %d: number of cylinders not specified",
1133 		    current_line_number);
1134 	    status = 0;
1135 	}
1136 	if (dos_cyls == 0 || dos_cyls > 1024)
1137 	{
1138 	    warnx(
1139 	"WARNING line %d: number of cylinders (%d) may be out-of-range\n\
1140     (must be within 1-1024 for normal BIOS operation, unless the entire disk\n\
1141     is dedicated to FreeBSD)",
1142 		    current_line_number, dos_cyls);
1143 	}
1144 
1145 	if (dos_heads < 0)
1146 	{
1147 	    warnx("ERROR line %d: number of heads not specified",
1148 		    current_line_number);
1149 	    status = 0;
1150 	}
1151 	else if (dos_heads < 1 || dos_heads > 256)
1152 	{
1153 	    warnx("ERROR line %d: number of heads must be within (1-256)",
1154 		    current_line_number);
1155 	    status = 0;
1156 	}
1157 
1158 	if (dos_sectors < 0)
1159 	{
1160 	    warnx("ERROR line %d: number of sectors not specified",
1161 		    current_line_number);
1162 	    status = 0;
1163 	}
1164 	else if (dos_sectors < 1 || dos_sectors > 63)
1165 	{
1166 	    warnx("ERROR line %d: number of sectors must be within (1-63)",
1167 		    current_line_number);
1168 	    status = 0;
1169 	}
1170 
1171 	break;
1172     }
1173     return (status);
1174 }
1175 
1176 
1177 static int
1178 process_partition(command)
1179     CMD		*command;
1180 {
1181     int				status = 0, partition;
1182     u_int32_t			prev_head_boundary, prev_cyl_boundary;
1183     u_int32_t			adj_size, max_end;
1184     struct dos_partition	*partp;
1185 
1186     while (1)
1187     {
1188 	part_processed = 1;
1189 	if (command->n_args != 4)
1190 	{
1191 	    warnx("ERROR line %d: incorrect number of partition args",
1192 		    current_line_number);
1193 	    break;
1194 	}
1195 	partition = command->args[0].arg_val;
1196 	if (partition < 1 || partition > 4)
1197 	{
1198 	    warnx("ERROR line %d: invalid partition number %d",
1199 		    current_line_number, partition);
1200 	    break;
1201 	}
1202 	partp = ((struct dos_partition *) &mboot.parts) + partition - 1;
1203 	bzero((char *)partp, sizeof (struct dos_partition));
1204 	partp->dp_typ = command->args[1].arg_val;
1205 	partp->dp_start = command->args[2].arg_val;
1206 	partp->dp_size = command->args[3].arg_val;
1207 	max_end = partp->dp_start + partp->dp_size;
1208 
1209 	if (partp->dp_typ == 0)
1210 	{
1211 	    /*
1212 	     * Get out, the partition is marked as unused.
1213 	     */
1214 	    /*
1215 	     * Insure that it's unused.
1216 	     */
1217 	    bzero((char *)partp, sizeof (struct dos_partition));
1218 	    status = 1;
1219 	    break;
1220 	}
1221 
1222 	/*
1223 	 * Adjust start upwards, if necessary, to fall on an head boundary.
1224 	 */
1225 	if (partp->dp_start % dos_sectors != 0)
1226 	{
1227 	    prev_head_boundary = partp->dp_start / dos_sectors * dos_sectors;
1228 	    if (max_end < dos_sectors ||
1229 		prev_head_boundary > max_end - dos_sectors)
1230 	    {
1231 		/*
1232 		 * Can't go past end of partition
1233 		 */
1234 		warnx(
1235 	"ERROR line %d: unable to adjust start of partition %d to fall on\n\
1236     a head boundary",
1237 			current_line_number, partition);
1238 		break;
1239 	    }
1240 	    warnx(
1241 	"WARNING: adjusting start offset of partition %d\n\
1242     from %u to %u, to fall on a head boundary",
1243 		    partition, (u_int)partp->dp_start,
1244 		    (u_int)(prev_head_boundary + dos_sectors));
1245 	    partp->dp_start = prev_head_boundary + dos_sectors;
1246 	}
1247 
1248 	/*
1249 	 * Adjust size downwards, if necessary, to fall on a cylinder
1250 	 * boundary.
1251 	 */
1252 	prev_cyl_boundary =
1253 	    ((partp->dp_start + partp->dp_size) / dos_cylsecs) * dos_cylsecs;
1254 	if (prev_cyl_boundary > partp->dp_start)
1255 	    adj_size = prev_cyl_boundary - partp->dp_start;
1256 	else
1257 	{
1258 	    warnx(
1259 	"ERROR: could not adjust partition to start on a head boundary\n\
1260     and end on a cylinder boundary.");
1261 	    return (0);
1262 	}
1263 	if (adj_size != partp->dp_size)
1264 	{
1265 	    warnx(
1266 	"WARNING: adjusting size of partition %d from %u to %u\n\
1267     to end on a cylinder boundary",
1268 		    partition, (u_int)partp->dp_size, (u_int)adj_size);
1269 	    partp->dp_size = adj_size;
1270 	}
1271 	if (partp->dp_size == 0)
1272 	{
1273 	    warnx("ERROR line %d: size of partition %d is zero",
1274 		    current_line_number, partition);
1275 	    break;
1276 	}
1277 
1278 	dos(partp);
1279 	status = 1;
1280 	break;
1281     }
1282     return (status);
1283 }
1284 
1285 
1286 static int
1287 process_active(command)
1288     CMD		*command;
1289 {
1290     int				status = 0, partition, i;
1291     struct dos_partition	*partp;
1292 
1293     while (1)
1294     {
1295 	active_processed = 1;
1296 	if (command->n_args != 1)
1297 	{
1298 	    warnx("ERROR line %d: incorrect number of active args",
1299 		    current_line_number);
1300 	    status = 0;
1301 	    break;
1302 	}
1303 	partition = command->args[0].arg_val;
1304 	if (partition < 1 || partition > 4)
1305 	{
1306 	    warnx("ERROR line %d: invalid partition number %d",
1307 		    current_line_number, partition);
1308 	    break;
1309 	}
1310 	/*
1311 	 * Reset active partition
1312 	 */
1313 	partp = ((struct dos_partition *) &mboot.parts);
1314 	for (i = 0; i < NDOSPART; i++)
1315 	    partp[i].dp_flag = 0;
1316 	partp[partition-1].dp_flag = ACTIVE;
1317 
1318 	status = 1;
1319 	break;
1320     }
1321     return (status);
1322 }
1323 
1324 
1325 static int
1326 process_line(line)
1327     char	*line;
1328 {
1329     CMD		command;
1330     int		status = 1;
1331 
1332     while (1)
1333     {
1334 	parse_config_line(line, &command);
1335 	switch (command.cmd)
1336 	{
1337 	case 0:
1338 	    /*
1339 	     * Comment or blank line
1340 	     */
1341 	    break;
1342 	case 'g':
1343 	    /*
1344 	     * Set geometry
1345 	     */
1346 	    status = process_geometry(&command);
1347 	    break;
1348 	case 'p':
1349 	    status = process_partition(&command);
1350 	    break;
1351 	case 'a':
1352 	    status = process_active(&command);
1353 	    break;
1354 	default:
1355 	    status = 0;
1356 	    break;
1357 	}
1358 	break;
1359     }
1360     return (status);
1361 }
1362 
1363 
1364 static int
1365 read_config(config_file)
1366     char *config_file;
1367 {
1368     FILE	*fp = NULL;
1369     int		status = 1;
1370     char	buf[1010];
1371 
1372     while (1)	/* dirty trick used to insure one exit point for this
1373 		   function */
1374     {
1375 	if (strcmp(config_file, "-") != 0)
1376 	{
1377 	    /*
1378 	     * We're not reading from stdin
1379 	     */
1380 	    if ((fp = fopen(config_file, "r")) == NULL)
1381 	    {
1382 		status = 0;
1383 		break;
1384 	    }
1385 	}
1386 	else
1387 	{
1388 	    fp = stdin;
1389 	}
1390 	current_line_number = 0;
1391 	while (!feof(fp))
1392 	{
1393 	    if (fgets(buf, sizeof(buf), fp) == NULL)
1394 	    {
1395 		break;
1396 	    }
1397 	    ++current_line_number;
1398 	    status = process_line(buf);
1399 	    if (status == 0)
1400 	    {
1401 		break;
1402 	    }
1403 	}
1404 	break;
1405     }
1406     if (fp)
1407     {
1408 	/*
1409 	 * It doesn't matter if we're reading from stdin, as we've reached EOF
1410 	 */
1411 	fclose(fp);
1412     }
1413     return (status);
1414 }
1415 
1416 
1417 static void
1418 reset_boot(void)
1419 {
1420     int				i;
1421     struct dos_partition	*partp;
1422 
1423     init_boot();
1424     for (i = 0; i < 4; ++i)
1425     {
1426 	partp = ((struct dos_partition *) &mboot.parts) + i;
1427 	bzero((char *)partp, sizeof (struct dos_partition));
1428     }
1429 }
1430 
1431 static int
1432 sanitize_partition(partp)
1433     struct dos_partition	*partp;
1434 {
1435     u_int32_t			prev_head_boundary, prev_cyl_boundary;
1436     u_int32_t			max_end, size, start;
1437 
1438     start = partp->dp_start;
1439     size = partp->dp_size;
1440     max_end = start + size;
1441     /* Only allow a zero size if the partition is being marked unused. */
1442     if (size == 0) {
1443 	if (start == 0 && partp->dp_typ == 0)
1444 	    return (1);
1445 	warnx("ERROR: size of partition is zero");
1446 	return (0);
1447     }
1448     /* Return if no adjustment is necessary. */
1449     if (start % dos_sectors == 0 && (start + size) % dos_sectors == 0)
1450 	return (1);
1451 
1452     if (start % dos_sectors != 0)
1453 	warnx("WARNING: partition does not start on a head boundary");
1454     if ((start  +size) % dos_sectors != 0)
1455 	warnx("WARNING: partition does not end on a cylinder boundary");
1456     warnx("WARNING: this may confuse the BIOS or some operating systems");
1457     if (!ok("Correct this automatically?"))
1458 	return (1);
1459 
1460     /*
1461      * Adjust start upwards, if necessary, to fall on an head boundary.
1462      */
1463     if (start % dos_sectors != 0) {
1464 	prev_head_boundary = start / dos_sectors * dos_sectors;
1465 	if (max_end < dos_sectors ||
1466 	    prev_head_boundary >= max_end - dos_sectors) {
1467 	    /*
1468 	     * Can't go past end of partition
1469 	     */
1470 	    warnx(
1471     "ERROR: unable to adjust start of partition to fall on a head boundary");
1472 	    return (0);
1473         }
1474 	start = prev_head_boundary + dos_sectors;
1475     }
1476 
1477     /*
1478      * Adjust size downwards, if necessary, to fall on a cylinder
1479      * boundary.
1480      */
1481     prev_cyl_boundary = ((start + size) / dos_cylsecs) * dos_cylsecs;
1482     if (prev_cyl_boundary > start)
1483 	size = prev_cyl_boundary - start;
1484     else {
1485 	warnx("ERROR: could not adjust partition to start on a head boundary\n\
1486     and end on a cylinder boundary.");
1487 	return (0);
1488     }
1489 
1490     /* Finally, commit any changes to partp and return. */
1491     if (start != partp->dp_start) {
1492 	warnx("WARNING: adjusting start offset of partition to %u",
1493 	    (u_int)start);
1494 	partp->dp_start = start;
1495     }
1496     if (size != partp->dp_size) {
1497 	warnx("WARNING: adjusting size of partition to %u", (u_int)size);
1498 	partp->dp_size = size;
1499     }
1500 
1501     return (1);
1502 }
1503 
1504 /*
1505  * Try figuring out the root device's canonical disk name.
1506  * The following choices are considered:
1507  *   /dev/ad0s1a     => /dev/ad0
1508  *   /dev/da0a       => /dev/da0
1509  *   /dev/vinum/root => /dev/vinum/root
1510  */
1511 static char *
1512 get_rootdisk(void)
1513 {
1514 	struct statfs rootfs;
1515 	regex_t re;
1516 #define NMATCHES 2
1517 	regmatch_t rm[NMATCHES];
1518 	char *s;
1519 	int rv;
1520 
1521 	if (statfs("/", &rootfs) == -1)
1522 		err(1, "statfs(\"/\")");
1523 
1524 	if ((rv = regcomp(&re, "^(/dev/.*)(\\d+(s\\d+)?[a-h])?$",
1525 		    REG_EXTENDED)) != 0)
1526 		errx(1, "regcomp() failed (%d)", rv);
1527 	if ((rv = regexec(&re, rootfs.f_mntfromname, NMATCHES, rm, 0)) != 0)
1528 		errx(1,
1529 "mounted root fs resource doesn't match expectations (regexec returned %d)",
1530 		    rv);
1531 	if ((s = malloc(rm[1].rm_eo - rm[1].rm_so + 1)) == NULL)
1532 		errx(1, "out of memory");
1533 	memcpy(s, rootfs.f_mntfromname + rm[1].rm_so,
1534 	    rm[1].rm_eo - rm[1].rm_so);
1535 	s[rm[1].rm_eo - rm[1].rm_so] = 0;
1536 
1537 	return s;
1538 }
1539