xref: /freebsd/sbin/fdisk/fdisk.c (revision 1669d8afc64812c8d2d1d147ae1fd42ff441e1b1)
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 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/disk.h>
31 #include <sys/disklabel.h>
32 #include <sys/diskmbr.h>
33 #include <sys/endian.h>
34 #include <sys/param.h>
35 #include <sys/stat.h>
36 #include <sys/mount.h>
37 #include <ctype.h>
38 #include <fcntl.h>
39 #include <err.h>
40 #include <errno.h>
41 #include <libgeom.h>
42 #include <paths.h>
43 #include <regex.h>
44 #include <stdint.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <unistd.h>
49 
50 int iotest;
51 
52 #define LBUF 100
53 static char lbuf[LBUF];
54 
55 /*
56  *
57  * Ported to 386bsd by Julian Elischer  Thu Oct 15 20:26:46 PDT 1992
58  *
59  * 14-Dec-89  Robert Baron (rvb) at Carnegie-Mellon University
60  *	Copyright (c) 1989	Robert. V. Baron
61  *	Created.
62  */
63 
64 #define Decimal(str, ans, tmp) if (decimal(str, &tmp, ans)) ans = tmp
65 
66 #define RoundCyl(x) ((((x) + cylsecs - 1) / cylsecs) * cylsecs)
67 
68 #define MAX_SEC_SIZE 2048	/* maximum section size that is supported */
69 #define MIN_SEC_SIZE 512	/* the sector size to start sensing at */
70 static int secsize = 0;		/* the sensed sector size */
71 
72 static char *disk;
73 
74 static int cyls, sectors, heads, cylsecs, disksecs;
75 
76 struct mboot {
77 	unsigned char padding[2]; /* force the longs to be long aligned */
78 	unsigned char *bootinst;  /* boot code */
79 	off_t bootinst_size;
80 	struct	dos_partition parts[NDOSPART];
81 };
82 
83 static struct mboot mboot;
84 static int fd;
85 
86 #define ACTIVE 0x80
87 
88 static uint dos_cyls;
89 static uint dos_heads;
90 static uint dos_sectors;
91 static uint dos_cylsecs;
92 
93 #define DOSSECT(s,c) ((s & 0x3f) | ((c >> 2) & 0xc0))
94 #define DOSCYL(c)	(c & 0xff)
95 
96 #define MAX_ARGS	10
97 
98 static int	current_line_number;
99 
100 static int	geom_processed = 0;
101 static int	part_processed = 0;
102 static int	active_processed = 0;
103 
104 typedef struct cmd {
105     char		cmd;
106     int			n_args;
107     struct arg {
108 	char	argtype;
109 	int	arg_val;
110     }			args[MAX_ARGS];
111 } CMD;
112 
113 static int B_flag  = 0;		/* replace boot code */
114 static int I_flag  = 0;		/* use entire disk for FreeBSD */
115 static int a_flag  = 0;		/* set active partition */
116 static char *b_flag = NULL;	/* path to boot code */
117 static int i_flag  = 0;		/* replace partition data */
118 static int u_flag  = 0;		/* update partition data */
119 static int s_flag  = 0;		/* Print a summary and exit */
120 static int t_flag  = 0;		/* test only */
121 static char *f_flag = NULL;	/* Read config info from file */
122 static int v_flag  = 0;		/* Be verbose */
123 static int print_config_flag = 0;
124 
125 static struct part_type
126 {
127 	unsigned char type;
128 	const char *name;
129 } part_types[] = {
130 	 {0x00, "unused"}
131 	,{0x01, "Primary DOS with 12 bit FAT"}
132 	,{0x02, "XENIX / file system"}
133 	,{0x03, "XENIX /usr file system"}
134 	,{0x04, "Primary DOS with 16 bit FAT (< 32MB)"}
135 	,{0x05, "Extended DOS"}
136 	,{0x06, "Primary 'big' DOS (>= 32MB)"}
137 	,{0x07, "OS/2 HPFS, NTFS, QNX-2 (16 bit) or Advanced UNIX"}
138 	,{0x08, "AIX file system or SplitDrive"}
139 	,{0x09, "AIX boot partition or Coherent"}
140 	,{0x0A, "OS/2 Boot Manager, OPUS or Coherent swap"}
141 	,{0x0B, "DOS or Windows 95 with 32 bit FAT"}
142 	,{0x0C, "DOS or Windows 95 with 32 bit FAT (LBA)"}
143 	,{0x0E, "Primary 'big' DOS (>= 32MB, LBA)"}
144 	,{0x0F, "Extended DOS (LBA)"}
145 	,{0x10, "OPUS"}
146 	,{0x11, "OS/2 BM: hidden DOS with 12-bit FAT"}
147 	,{0x12, "Compaq diagnostics"}
148 	,{0x14, "OS/2 BM: hidden DOS with 16-bit FAT (< 32MB)"}
149 	,{0x16, "OS/2 BM: hidden DOS with 16-bit FAT (>= 32MB)"}
150 	,{0x17, "OS/2 BM: hidden IFS (e.g. HPFS)"}
151 	,{0x18, "AST Windows swapfile"}
152 	,{0x24, "NEC DOS"}
153 	,{0x3C, "PartitionMagic recovery"}
154 	,{0x39, "plan9"}
155 	,{0x40, "VENIX 286"}
156 	,{0x41, "Linux/MINIX (sharing disk with DRDOS)"}
157 	,{0x42, "SFS or Linux swap (sharing disk with DRDOS)"}
158 	,{0x43, "Linux native (sharing disk with DRDOS)"}
159 	,{0x4D, "QNX 4.2 Primary"}
160 	,{0x4E, "QNX 4.2 Secondary"}
161 	,{0x4F, "QNX 4.2 Tertiary"}
162 	,{0x50, "DM (disk manager)"}
163 	,{0x51, "DM6 Aux1 (or Novell)"}
164 	,{0x52, "CP/M or Microport SysV/AT"}
165 	,{0x53, "DM6 Aux3"}
166 	,{0x54, "DM6"}
167 	,{0x55, "EZ-Drive (disk manager)"}
168 	,{0x56, "Golden Bow (disk manager)"}
169 	,{0x5c, "Priam Edisk (disk manager)"} /* according to S. Widlake */
170 	,{0x61, "SpeedStor"}
171 	,{0x63, "System V/386 (such as ISC UNIX), GNU HURD or Mach"}
172 	,{0x64, "Novell Netware/286 2.xx"}
173 	,{0x65, "Novell Netware/386 3.xx"}
174 	,{0x70, "DiskSecure Multi-Boot"}
175 	,{0x75, "PCIX"}
176 	,{0x77, "QNX4.x"}
177 	,{0x78, "QNX4.x 2nd part"}
178 	,{0x79, "QNX4.x 3rd part"}
179 	,{0x80, "Minix until 1.4a"}
180 	,{0x81, "Minix since 1.4b, early Linux partition or Mitac disk manager"}
181 	,{0x82, "Linux swap or Solaris x86"}
182 	,{0x83, "Linux native"}
183 	,{0x84, "OS/2 hidden C: drive"}
184 	,{0x85, "Linux extended"}
185 	,{0x86, "NTFS volume set??"}
186 	,{0x87, "NTFS volume set??"}
187 	,{0x93, "Amoeba file system"}
188 	,{0x94, "Amoeba bad block table"}
189 	,{0x9F, "BSD/OS"}
190 	,{0xA0, "Suspend to Disk"}
191 	,{0xA5, "FreeBSD/NetBSD/386BSD"}
192 	,{0xA6, "OpenBSD"}
193 	,{0xA7, "NeXTSTEP"}
194 	,{0xA9, "NetBSD"}
195 	,{0xAC, "IBM JFS"}
196 	,{0xAF, "HFS+"}
197 	,{0xB7, "BSDI BSD/386 file system"}
198 	,{0xB8, "BSDI BSD/386 swap"}
199 	,{0xBE, "Solaris x86 boot"}
200 	,{0xBF, "Solaris x86 (new)"}
201 	,{0xC1, "DRDOS/sec with 12-bit FAT"}
202 	,{0xC4, "DRDOS/sec with 16-bit FAT (< 32MB)"}
203 	,{0xC6, "DRDOS/sec with 16-bit FAT (>= 32MB)"}
204 	,{0xC7, "Syrinx"}
205 	,{0xDB, "CP/M, Concurrent CP/M, Concurrent DOS or CTOS"}
206 	,{0xE1, "DOS access or SpeedStor with 12-bit FAT extended partition"}
207 	,{0xE3, "DOS R/O or SpeedStor"}
208 	,{0xE4, "SpeedStor with 16-bit FAT extended partition < 1024 cyl."}
209 	,{0xEB, "BeOS file system"}
210 	,{0xEE, "EFI GPT"}
211 	,{0xEF, "EFI System Partition"}
212 	,{0xF1, "SpeedStor"}
213 	,{0xF2, "DOS 3.3+ Secondary"}
214 	,{0xF4, "SpeedStor large partition"}
215 	,{0xFE, "SpeedStor >1024 cyl. or LANstep"}
216 	,{0xFF, "Xenix bad blocks table"}
217 };
218 
219 static void print_s0(int which);
220 static void print_part(int i);
221 static void init_sector0(unsigned long start);
222 static void init_boot(void);
223 static void change_part(int i);
224 static void print_params(void);
225 static void change_active(int which);
226 static void change_code(void);
227 static void get_params_to_use(void);
228 static char *get_rootdisk(void);
229 static void dos(struct dos_partition *partp);
230 static int open_disk(int flag);
231 static ssize_t read_disk(off_t sector, void *buf);
232 static int write_disk(off_t sector, void *buf);
233 static int get_params(void);
234 static int read_s0(void);
235 static int write_s0(void);
236 static int ok(const char *str);
237 static int decimal(const char *str, int *num, int deflt);
238 static const char *get_type(int type);
239 static int read_config(char *config_file);
240 static void reset_boot(void);
241 static int sanitize_partition(struct dos_partition *);
242 static void usage(void);
243 
244 int
245 main(int argc, char *argv[])
246 {
247 	struct	stat sb;
248 	int	c, i;
249 	int	partition = -1;
250 	struct	dos_partition *partp;
251 
252 	while ((c = getopt(argc, argv, "BIab:f:ipstuv1234")) != -1)
253 		switch (c) {
254 		case 'B':
255 			B_flag = 1;
256 			break;
257 		case 'I':
258 			I_flag = 1;
259 			break;
260 		case 'a':
261 			a_flag = 1;
262 			break;
263 		case 'b':
264 			b_flag = optarg;
265 			break;
266 		case 'f':
267 			f_flag = optarg;
268 			break;
269 		case 'i':
270 			i_flag = 1;
271 			break;
272 		case 'p':
273 			print_config_flag = 1;
274 			break;
275 		case 's':
276 			s_flag = 1;
277 			break;
278 		case 't':
279 			t_flag = 1;
280 			break;
281 		case 'u':
282 			u_flag = 1;
283 			break;
284 		case 'v':
285 			v_flag = 1;
286 			break;
287 		case '1':
288 		case '2':
289 		case '3':
290 		case '4':
291 			partition = c - '0';
292 			break;
293 		default:
294 			usage();
295 		}
296 	if (f_flag || i_flag)
297 		u_flag = 1;
298 	if (t_flag)
299 		v_flag = 1;
300 	argc -= optind;
301 	argv += optind;
302 
303 	if (argc == 0) {
304 		disk = get_rootdisk();
305 	} else {
306 		if (stat(argv[0], &sb) == 0) {
307 			/* OK, full pathname given */
308 			disk = argv[0];
309 		} else if (errno == ENOENT && argv[0][0] != '/') {
310 			/* Try prepending "/dev" */
311 			asprintf(&disk, "%s%s", _PATH_DEV, argv[0]);
312 			if (disk == NULL)
313 				errx(1, "out of memory");
314 		} else {
315 			/* other stat error, let it fail below */
316 			disk = argv[0];
317 		}
318 	}
319 	if (open_disk(u_flag) < 0)
320 		err(1, "cannot open disk %s", disk);
321 
322 	/* (abu)use mboot.bootinst to probe for the sector size */
323 	if ((mboot.bootinst = malloc(MAX_SEC_SIZE)) == NULL)
324 		err(1, "cannot allocate buffer to determine disk sector size");
325 	if (read_disk(0, mboot.bootinst) == -1)
326 		errx(1, "could not detect sector size");
327 	free(mboot.bootinst);
328 	mboot.bootinst = NULL;
329 
330 	if (print_config_flag) {
331 		if (read_s0())
332 			err(1, "read_s0");
333 
334 		printf("# %s\n", disk);
335 		printf("g c%d h%d s%d\n", dos_cyls, dos_heads, dos_sectors);
336 
337 		for (i = 0; i < NDOSPART; i++) {
338 			partp = ((struct dos_partition *)&mboot.parts) + i;
339 
340 			if (partp->dp_start == 0 && partp->dp_size == 0)
341 				continue;
342 
343 			printf("p %d 0x%02x %lu %lu\n", i + 1, partp->dp_typ,
344 			    (u_long)partp->dp_start, (u_long)partp->dp_size);
345 
346 			/* Fill flags for the partition. */
347 			if (partp->dp_flag & 0x80)
348 				printf("a %d\n", i + 1);
349 		}
350 		exit(0);
351 	}
352 	if (s_flag) {
353 		if (read_s0())
354 			err(1, "read_s0");
355 		printf("%s: %d cyl %d hd %d sec\n", disk, dos_cyls, dos_heads,
356 		    dos_sectors);
357 		printf("Part  %11s %11s Type Flags\n", "Start", "Size");
358 		for (i = 0; i < NDOSPART; i++) {
359 			partp = ((struct dos_partition *) &mboot.parts) + i;
360 			if (partp->dp_start == 0 && partp->dp_size == 0)
361 				continue;
362 			printf("%4d: %11lu %11lu 0x%02x 0x%02x\n", i + 1,
363 			    (u_long) partp->dp_start,
364 			    (u_long) partp->dp_size, partp->dp_typ,
365 			    partp->dp_flag);
366 		}
367 		exit(0);
368 	}
369 
370 	printf("******* Working on device %s *******\n",disk);
371 
372 	if (I_flag) {
373 		read_s0();
374 		reset_boot();
375 		partp = (struct dos_partition *) (&mboot.parts[0]);
376 		partp->dp_typ = DOSPTYP_386BSD;
377 		partp->dp_flag = ACTIVE;
378 		partp->dp_start = dos_sectors;
379 		partp->dp_size = (disksecs / dos_cylsecs) * dos_cylsecs -
380 		    dos_sectors;
381 		dos(partp);
382 		if (v_flag)
383 			print_s0(-1);
384 		if (!t_flag)
385 			write_s0();
386 		exit(0);
387 	}
388 	if (f_flag) {
389 	    if (read_s0() || i_flag)
390 		reset_boot();
391 	    if (!read_config(f_flag))
392 		exit(1);
393 	    if (v_flag)
394 		print_s0(-1);
395 	    if (!t_flag)
396 		write_s0();
397 	} else {
398 	    if(u_flag)
399 		get_params_to_use();
400 	    else
401 		print_params();
402 
403 	    if (read_s0())
404 		init_sector0(dos_sectors);
405 
406 	    printf("Media sector size is %d\n", secsize);
407 	    printf("Warning: BIOS sector numbering starts with sector 1\n");
408 	    printf("Information from DOS bootblock is:\n");
409 	    if (partition == -1)
410 		for (i = 1; i <= NDOSPART; i++)
411 		    change_part(i);
412 	    else
413 		change_part(partition);
414 
415 	    if (u_flag || a_flag)
416 		change_active(partition);
417 
418 	    if (B_flag)
419 		change_code();
420 
421 	    if (u_flag || a_flag || B_flag) {
422 		if (!t_flag) {
423 		    printf("\nWe haven't changed the partition table yet.  ");
424 		    printf("This is your last chance.\n");
425 		}
426 		print_s0(-1);
427 		if (!t_flag) {
428 		    if (ok("Should we write new partition table?"))
429 			write_s0();
430 		} else {
431 		    printf("\n-t flag specified -- partition table not written.\n");
432 		}
433 	    }
434 	}
435 
436 	exit(0);
437 }
438 
439 static void
440 usage()
441 {
442 	fprintf(stderr, "%s%s",
443 		"usage: fdisk [-BIaipstu] [-b bootcode] [-1234] [disk]\n",
444  		"       fdisk -f configfile [-itv] [disk]\n");
445         exit(1);
446 }
447 
448 static void
449 print_s0(int which)
450 {
451 	int	i;
452 
453 	print_params();
454 	printf("Information from DOS bootblock is:\n");
455 	if (which == -1)
456 		for (i = 1; i <= NDOSPART; i++)
457 			printf("%d: ", i), print_part(i);
458 	else
459 		print_part(which);
460 }
461 
462 static struct dos_partition mtpart;
463 
464 static void
465 print_part(int i)
466 {
467 	struct	  dos_partition *partp;
468 	u_int64_t part_mb;
469 
470 	partp = ((struct dos_partition *) &mboot.parts) + i - 1;
471 
472 	if (!bcmp(partp, &mtpart, sizeof (struct dos_partition))) {
473 		printf("<UNUSED>\n");
474 		return;
475 	}
476 	/*
477 	 * Be careful not to overflow.
478 	 */
479 	part_mb = partp->dp_size;
480 	part_mb *= secsize;
481 	part_mb /= (1024 * 1024);
482 	printf("sysid %d (%#04x),(%s)\n", partp->dp_typ, partp->dp_typ,
483 	    get_type(partp->dp_typ));
484 	printf("    start %lu, size %lu (%ju Meg), flag %x%s\n",
485 		(u_long)partp->dp_start,
486 		(u_long)partp->dp_size,
487 		(uintmax_t)part_mb,
488 		partp->dp_flag,
489 		partp->dp_flag == ACTIVE ? " (active)" : "");
490 	printf("\tbeg: cyl %d/ head %d/ sector %d;\n\tend: cyl %d/ head %d/ sector %d\n"
491 		,DPCYL(partp->dp_scyl, partp->dp_ssect)
492 		,partp->dp_shd
493 		,DPSECT(partp->dp_ssect)
494 		,DPCYL(partp->dp_ecyl, partp->dp_esect)
495 		,partp->dp_ehd
496 		,DPSECT(partp->dp_esect));
497 }
498 
499 
500 static void
501 init_boot(void)
502 {
503 #ifndef __ia64__
504 	const char *fname;
505 	int fdesc, n;
506 	struct stat sb;
507 
508 	fname = b_flag ? b_flag : "/boot/mbr";
509 	if ((fdesc = open(fname, O_RDONLY)) == -1 ||
510 	    fstat(fdesc, &sb) == -1)
511 		err(1, "%s", fname);
512 	if ((mboot.bootinst_size = sb.st_size) % secsize != 0)
513 		errx(1, "%s: length must be a multiple of sector size", fname);
514 	if (mboot.bootinst != NULL)
515 		free(mboot.bootinst);
516 	if ((mboot.bootinst = malloc(mboot.bootinst_size = sb.st_size)) == NULL)
517 		errx(1, "%s: unable to allocate read buffer", fname);
518 	if ((n = read(fdesc, mboot.bootinst, mboot.bootinst_size)) == -1 ||
519 	    close(fdesc))
520 		err(1, "%s", fname);
521 	if (n != mboot.bootinst_size)
522 		errx(1, "%s: short read", fname);
523 #else
524 	if (mboot.bootinst != NULL)
525 		free(mboot.bootinst);
526 	mboot.bootinst_size = secsize;
527 	if ((mboot.bootinst = malloc(mboot.bootinst_size)) == NULL)
528 		errx(1, "unable to allocate boot block buffer");
529 	memset(mboot.bootinst, 0, mboot.bootinst_size);
530 	le16enc(&mboot.bootinst[DOSMAGICOFFSET], DOSMAGIC);
531 #endif
532 }
533 
534 
535 static void
536 init_sector0(unsigned long start)
537 {
538 	struct dos_partition *partp = (struct dos_partition *) (&mboot.parts[0]);
539 
540 	init_boot();
541 
542 	partp->dp_typ = DOSPTYP_386BSD;
543 	partp->dp_flag = ACTIVE;
544 	start = ((start + dos_sectors - 1) / dos_sectors) * dos_sectors;
545 	if(start == 0)
546 		start = dos_sectors;
547 	partp->dp_start = start;
548 	partp->dp_size = (disksecs / dos_cylsecs) * dos_cylsecs - start;
549 
550 	dos(partp);
551 }
552 
553 static void
554 change_part(int i)
555 {
556 	struct dos_partition *partp = ((struct dos_partition *) &mboot.parts) + i - 1;
557 
558     printf("The data for partition %d is:\n", i);
559     print_part(i);
560 
561     if (u_flag && ok("Do you want to change it?")) {
562 	int tmp;
563 
564 	if (i_flag) {
565 		bzero((char *)partp, sizeof (struct dos_partition));
566 		if (i == 1) {
567 			init_sector0(1);
568 			printf("\nThe static data for the slice 1 has been reinitialized to:\n");
569 			print_part(i);
570 		}
571 	}
572 
573 	do {
574 		Decimal("sysid (165=FreeBSD)", partp->dp_typ, tmp);
575 		Decimal("start", partp->dp_start, tmp);
576 		Decimal("size", partp->dp_size, tmp);
577 		if (!sanitize_partition(partp)) {
578 			warnx("ERROR: failed to adjust; setting sysid to 0");
579 			partp->dp_typ = 0;
580 		}
581 
582 		if (ok("Explicitly specify beg/end address ?"))
583 		{
584 			int	tsec,tcyl,thd;
585 			tcyl = DPCYL(partp->dp_scyl,partp->dp_ssect);
586 			thd = partp->dp_shd;
587 			tsec = DPSECT(partp->dp_ssect);
588 			Decimal("beginning cylinder", tcyl, tmp);
589 			Decimal("beginning head", thd, tmp);
590 			Decimal("beginning sector", tsec, tmp);
591 			partp->dp_scyl = DOSCYL(tcyl);
592 			partp->dp_ssect = DOSSECT(tsec,tcyl);
593 			partp->dp_shd = thd;
594 
595 			tcyl = DPCYL(partp->dp_ecyl,partp->dp_esect);
596 			thd = partp->dp_ehd;
597 			tsec = DPSECT(partp->dp_esect);
598 			Decimal("ending cylinder", tcyl, tmp);
599 			Decimal("ending head", thd, tmp);
600 			Decimal("ending sector", tsec, tmp);
601 			partp->dp_ecyl = DOSCYL(tcyl);
602 			partp->dp_esect = DOSSECT(tsec,tcyl);
603 			partp->dp_ehd = thd;
604 		} else
605 			dos(partp);
606 
607 		print_part(i);
608 	} while (!ok("Are we happy with this entry?"));
609     }
610 }
611 
612 static void
613 print_params()
614 {
615 	printf("parameters extracted from in-core disklabel are:\n");
616 	printf("cylinders=%d heads=%d sectors/track=%d (%d blks/cyl)\n\n"
617 			,cyls,heads,sectors,cylsecs);
618 	if (dos_cyls > 1023 || dos_heads > 255 || dos_sectors > 63)
619 		printf("Figures below won't work with BIOS for partitions not in cyl 1\n");
620 	printf("parameters to be used for BIOS calculations are:\n");
621 	printf("cylinders=%d heads=%d sectors/track=%d (%d blks/cyl)\n\n"
622 		,dos_cyls,dos_heads,dos_sectors,dos_cylsecs);
623 }
624 
625 static void
626 change_active(int which)
627 {
628 	struct dos_partition *partp = &mboot.parts[0];
629 	int active, i, new, tmp;
630 
631 	active = -1;
632 	for (i = 0; i < NDOSPART; i++) {
633 		if ((partp[i].dp_flag & ACTIVE) == 0)
634 			continue;
635 		printf("Partition %d is marked active\n", i + 1);
636 		if (active == -1)
637 			active = i + 1;
638 	}
639 	if (a_flag && which != -1)
640 		active = which;
641 	else if (active == -1)
642 		active = 1;
643 
644 	if (!ok("Do you want to change the active partition?"))
645 		return;
646 setactive:
647 	do {
648 		new = active;
649 		Decimal("active partition", new, tmp);
650 		if (new < 1 || new > 4) {
651 			printf("Active partition number must be in range 1-4."
652 					"  Try again.\n");
653 			goto setactive;
654 		}
655 		active = new;
656 	} while (!ok("Are you happy with this choice"));
657 	for (i = 0; i < NDOSPART; i++)
658 		partp[i].dp_flag = 0;
659 	if (active > 0 && active <= NDOSPART)
660 		partp[active-1].dp_flag = ACTIVE;
661 }
662 
663 static void
664 change_code()
665 {
666 	if (ok("Do you want to change the boot code?"))
667 		init_boot();
668 }
669 
670 void
671 get_params_to_use()
672 {
673 	int	tmp;
674 	print_params();
675 	if (ok("Do you want to change our idea of what BIOS thinks ?"))
676 	{
677 		do
678 		{
679 			Decimal("BIOS's idea of #cylinders", dos_cyls, tmp);
680 			Decimal("BIOS's idea of #heads", dos_heads, tmp);
681 			Decimal("BIOS's idea of #sectors", dos_sectors, tmp);
682 			dos_cylsecs = dos_heads * dos_sectors;
683 			print_params();
684 		}
685 		while(!ok("Are you happy with this choice"));
686 	}
687 }
688 
689 
690 /***********************************************\
691 * Change real numbers into strange dos numbers	*
692 \***********************************************/
693 static void
694 dos(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 static int
721 open_disk(int flag)
722 {
723 	struct stat 	st;
724 	int rwmode;
725 
726 	if (stat(disk, &st) == -1) {
727 		if (errno == ENOENT)
728 			return -2;
729 		warnx("can't get file status of %s", disk);
730 		return -1;
731 	}
732 	if ( !(st.st_mode & S_IFCHR) )
733 		warnx("device %s is not character special", disk);
734 	rwmode = a_flag || I_flag || B_flag || flag ? O_RDWR : O_RDONLY;
735 	fd = open(disk, rwmode);
736 	if (fd == -1 && errno == EPERM && rwmode == O_RDWR)
737 		fd = open(disk, O_RDONLY);
738 	if (fd == -1 && errno == ENXIO)
739 		return -2;
740 	if (fd == -1) {
741 		warnx("can't open device %s", disk);
742 		return -1;
743 	}
744 	if (get_params() == -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 
755 	lseek(fd, (sector * 512), 0);
756 	if (secsize == 0)
757 		for (secsize = MIN_SEC_SIZE; secsize <= MAX_SEC_SIZE;
758 		     secsize *= 2) {
759 			/* try the read */
760 			int size = read(fd, buf, secsize);
761 			if (size == secsize)
762 				/* it worked so return */
763 				return secsize;
764 		}
765 	else
766 		return read(fd, buf, secsize);
767 
768 	/* we failed to read at any of the sizes */
769 	return -1;
770 }
771 
772 static int
773 write_disk(off_t sector, void *buf)
774 {
775 	int error;
776 	struct gctl_req *grq;
777 	const char *q;
778 	char fbuf[BUFSIZ];
779 	int i, fdw;
780 
781 	grq = gctl_get_handle();
782 	gctl_ro_param(grq, "verb", -1, "write MBR");
783 	gctl_ro_param(grq, "class", -1, "MBR");
784 	q = strrchr(disk, '/');
785 	if (q == NULL)
786 		q = disk;
787 	else
788 		q++;
789 	gctl_ro_param(grq, "geom", -1, q);
790 	gctl_ro_param(grq, "data", secsize, buf);
791 	q = gctl_issue(grq);
792 	if (q == NULL) {
793 		gctl_free(grq);
794 		return(0);
795 	}
796 	warnx("%s", q);
797 	gctl_free(grq);
798 
799 	error = pwrite(fd, buf, secsize, (sector * 512));
800 	if (error == secsize)
801 		return (0);
802 
803 	for (i = 1; i < 5; i++) {
804 		sprintf(fbuf, "%ss%d", disk, i);
805 		fdw = open(fbuf, O_RDWR, 0);
806 		if (fdw < 0)
807 			continue;
808 		error = ioctl(fdw, DIOCSMBR, buf);
809 		close(fdw);
810 		if (error == 0)
811 			return (0);
812 	}
813 	warnx("Failed to write sector zero");
814 	return(EINVAL);
815 }
816 
817 static int
818 get_params()
819 {
820 	int error;
821 	u_int u;
822 	off_t o;
823 
824 	error = ioctl(fd, DIOCGFWSECTORS, &u);
825 	if (error == 0)
826 		sectors = dos_sectors = u;
827 	else
828 		sectors = dos_sectors = 63;
829 
830 	error = ioctl(fd, DIOCGFWHEADS, &u);
831 	if (error == 0)
832 		heads = dos_heads = u;
833 	else
834 		heads = dos_heads = 255;
835 
836 	dos_cylsecs = cylsecs = heads * sectors;
837 	disksecs = cyls * heads * sectors;
838 
839 	error = ioctl(fd, DIOCGSECTORSIZE, &u);
840 	if (error != 0 || u == 0)
841 		u = 512;
842 	else
843 		secsize = u;
844 
845 	error = ioctl(fd, DIOCGMEDIASIZE, &o);
846 	if (error == 0) {
847 		disksecs = o / u;
848 		cyls = dos_cyls = o / (u * dos_heads * dos_sectors);
849 	}
850 
851 	return (disksecs);
852 }
853 
854 
855 static int
856 read_s0()
857 {
858 	int i;
859 
860 	mboot.bootinst_size = secsize;
861 	if (mboot.bootinst != NULL)
862 		free(mboot.bootinst);
863 	if ((mboot.bootinst = malloc(mboot.bootinst_size)) == NULL) {
864 		warnx("unable to allocate buffer to read fdisk "
865 		      "partition table");
866 		return -1;
867 	}
868 	if (read_disk(0, mboot.bootinst) == -1) {
869 		warnx("can't read fdisk partition table");
870 		return -1;
871 	}
872 	if (le16dec(&mboot.bootinst[DOSMAGICOFFSET]) != DOSMAGIC) {
873 		warnx("invalid fdisk partition table found");
874 		/* So should we initialize things */
875 		return -1;
876 	}
877 	for (i = 0; i < NDOSPART; i++)
878 		dos_partition_dec(
879 		    &mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
880 		    &mboot.parts[i]);
881 	return 0;
882 }
883 
884 static int
885 write_s0()
886 {
887 	int	sector, i;
888 
889 	if (iotest) {
890 		print_s0(-1);
891 		return 0;
892 	}
893 	for(i = 0; i < NDOSPART; i++)
894 		dos_partition_enc(&mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
895 		    &mboot.parts[i]);
896 	le16enc(&mboot.bootinst[DOSMAGICOFFSET], DOSMAGIC);
897 	for(sector = 0; sector < mboot.bootinst_size / secsize; sector++)
898 		if (write_disk(sector,
899 			       &mboot.bootinst[sector * secsize]) == -1) {
900 			warn("can't write fdisk partition table");
901 			return -1;
902 		}
903 	return(0);
904 }
905 
906 
907 static int
908 ok(const char *str)
909 {
910 	printf("%s [n] ", str);
911 	fflush(stdout);
912 	if (fgets(lbuf, LBUF, stdin) == NULL)
913 		exit(1);
914 	lbuf[strlen(lbuf)-1] = 0;
915 
916 	if (*lbuf &&
917 		(!strcmp(lbuf, "yes") || !strcmp(lbuf, "YES") ||
918 		 !strcmp(lbuf, "y") || !strcmp(lbuf, "Y")))
919 		return 1;
920 	else
921 		return 0;
922 }
923 
924 static int
925 decimal(const char *str, int *num, int deflt)
926 {
927 	int acc = 0, c;
928 	char *cp;
929 
930 	while (1) {
931 		printf("Supply a decimal value for \"%s\" [%d] ", str, deflt);
932 		fflush(stdout);
933 		if (fgets(lbuf, LBUF, stdin) == NULL)
934 			exit(1);
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 * 10 + c - '0';
947 			else
948 				break;
949 		}
950 		if (c == ' ' || c == '\t')
951 			while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
952 		if (!c) {
953 			*num = acc;
954 			return 1;
955 		} else
956 			printf("%s is an invalid decimal number.  Try again.\n",
957 				lbuf);
958 	}
959 
960 }
961 
962 static const char *
963 get_type(int type)
964 {
965 	int	numentries = (sizeof(part_types)/sizeof(struct part_type));
966 	int	counter = 0;
967 	struct	part_type *ptr = part_types;
968 
969 
970 	while(counter < numentries) {
971 		if(ptr->type == type)
972 			return(ptr->name);
973 		ptr++;
974 		counter++;
975 	}
976 	return("unknown");
977 }
978 
979 
980 static void
981 parse_config_line(char *line, CMD *command)
982 {
983     char	*cp, *end;
984 
985     cp = line;
986     while (1) {
987 	memset(command, 0, sizeof(*command));
988 
989 	while (isspace(*cp)) ++cp;
990 	if (*cp == '\0' || *cp == '#')
991 	    break;
992 	command->cmd = *cp++;
993 
994 	/*
995 	 * Parse args
996 	 */
997 	    while (1) {
998 	    while (isspace(*cp)) ++cp;
999 	    if (*cp == '#')
1000 		break;		/* found comment */
1001 	    if (isalpha(*cp))
1002 		command->args[command->n_args].argtype = *cp++;
1003 	    if (!isdigit(*cp))
1004 		break;		/* assume end of line */
1005 	    end = NULL;
1006 	    command->args[command->n_args].arg_val = strtol(cp, &end, 0);
1007 	    if (cp == end)
1008 		break;		/* couldn't parse number */
1009 	    cp = end;
1010 	    command->n_args++;
1011 	}
1012 	break;
1013     }
1014 }
1015 
1016 
1017 static int
1018 process_geometry(CMD *command)
1019 {
1020     int		status = 1, i;
1021 
1022     while (1) {
1023 	geom_processed = 1;
1024 	    if (part_processed) {
1025 	    warnx(
1026 	"ERROR line %d: the geometry specification line must occur before\n\
1027     all partition specifications",
1028 		    current_line_number);
1029 	    status = 0;
1030 	    break;
1031 	}
1032 	    if (command->n_args != 3) {
1033 	    warnx("ERROR line %d: incorrect number of geometry args",
1034 		    current_line_number);
1035 	    status = 0;
1036 	    break;
1037 	}
1038 	    dos_cyls = 0;
1039 	    dos_heads = 0;
1040 	    dos_sectors = 0;
1041 	    for (i = 0; i < 3; ++i) {
1042 		    switch (command->args[i].argtype) {
1043 	    case 'c':
1044 		dos_cyls = command->args[i].arg_val;
1045 		break;
1046 	    case 'h':
1047 		dos_heads = command->args[i].arg_val;
1048 		break;
1049 	    case 's':
1050 		dos_sectors = command->args[i].arg_val;
1051 		break;
1052 	    default:
1053 		warnx(
1054 		"ERROR line %d: unknown geometry arg type: '%c' (0x%02x)",
1055 			current_line_number, command->args[i].argtype,
1056 			command->args[i].argtype);
1057 		status = 0;
1058 		break;
1059 	    }
1060 	}
1061 	if (status == 0)
1062 	    break;
1063 
1064 	dos_cylsecs = dos_heads * dos_sectors;
1065 
1066 	/*
1067 	 * Do sanity checks on parameter values
1068 	 */
1069 	    if (dos_cyls == 0) {
1070 	    warnx("ERROR line %d: number of cylinders not specified",
1071 		    current_line_number);
1072 	    status = 0;
1073 	}
1074 	    if (dos_cyls > 1024) {
1075 	    warnx(
1076 	"WARNING line %d: number of cylinders (%d) may be out-of-range\n\
1077     (must be within 1-1024 for normal BIOS operation, unless the entire disk\n\
1078     is dedicated to FreeBSD)",
1079 		    current_line_number, dos_cyls);
1080 	}
1081 
1082 	    if (dos_heads == 0) {
1083 	    warnx("ERROR line %d: number of heads not specified",
1084 		    current_line_number);
1085 	    status = 0;
1086 	    } else if (dos_heads > 256) {
1087 	    warnx("ERROR line %d: number of heads must be within (1-256)",
1088 		    current_line_number);
1089 	    status = 0;
1090 	}
1091 
1092 	    if (dos_sectors == 0) {
1093 	    warnx("ERROR line %d: number of sectors not specified",
1094 		    current_line_number);
1095 	    status = 0;
1096 	    } else if (dos_sectors > 63) {
1097 	    warnx("ERROR line %d: number of sectors must be within (1-63)",
1098 		    current_line_number);
1099 	    status = 0;
1100 	}
1101 
1102 	break;
1103     }
1104     return (status);
1105 }
1106 
1107 
1108 static int
1109 process_partition(CMD *command)
1110 {
1111     int				status = 0, partition;
1112     u_int32_t			prev_head_boundary, prev_cyl_boundary;
1113     u_int32_t			adj_size, max_end;
1114     struct dos_partition	*partp;
1115 
1116 	while (1) {
1117 	part_processed = 1;
1118 		if (command->n_args != 4) {
1119 	    warnx("ERROR line %d: incorrect number of partition args",
1120 		    current_line_number);
1121 	    break;
1122 	}
1123 	partition = command->args[0].arg_val;
1124 		if (partition < 1 || partition > 4) {
1125 	    warnx("ERROR line %d: invalid partition number %d",
1126 		    current_line_number, partition);
1127 	    break;
1128 	}
1129 	partp = ((struct dos_partition *) &mboot.parts) + partition - 1;
1130 	bzero((char *)partp, sizeof (struct dos_partition));
1131 	partp->dp_typ = command->args[1].arg_val;
1132 	partp->dp_start = command->args[2].arg_val;
1133 	partp->dp_size = command->args[3].arg_val;
1134 	max_end = partp->dp_start + partp->dp_size;
1135 
1136 		if (partp->dp_typ == 0) {
1137 	    /*
1138 	     * Get out, the partition is marked as unused.
1139 	     */
1140 	    /*
1141 	     * Insure that it's unused.
1142 	     */
1143 	    bzero((char *)partp, sizeof (struct dos_partition));
1144 	    status = 1;
1145 	    break;
1146 	}
1147 
1148 	/*
1149 	 * Adjust start upwards, if necessary, to fall on a head boundary.
1150 	 */
1151 		if (partp->dp_start % dos_sectors != 0) {
1152 	    prev_head_boundary = partp->dp_start / dos_sectors * dos_sectors;
1153 	    if (max_end < dos_sectors ||
1154 			    prev_head_boundary > max_end - dos_sectors) {
1155 		/*
1156 		 * Can't go past end of partition
1157 		 */
1158 		warnx(
1159 	"ERROR line %d: unable to adjust start of partition %d to fall on\n\
1160     a head boundary",
1161 			current_line_number, partition);
1162 		break;
1163 	    }
1164 	    warnx(
1165 	"WARNING: adjusting start offset of partition %d\n\
1166     from %u to %u, to fall on a head boundary",
1167 		    partition, (u_int)partp->dp_start,
1168 		    (u_int)(prev_head_boundary + dos_sectors));
1169 	    partp->dp_start = prev_head_boundary + dos_sectors;
1170 	}
1171 
1172 	/*
1173 	 * Adjust size downwards, if necessary, to fall on a cylinder
1174 	 * boundary.
1175 	 */
1176 	prev_cyl_boundary =
1177 	    ((partp->dp_start + partp->dp_size) / dos_cylsecs) * dos_cylsecs;
1178 	if (prev_cyl_boundary > partp->dp_start)
1179 	    adj_size = prev_cyl_boundary - partp->dp_start;
1180 		else {
1181 	    warnx(
1182 	"ERROR: could not adjust partition to start on a head boundary\n\
1183     and end on a cylinder boundary.");
1184 	    return (0);
1185 	}
1186 		if (adj_size != partp->dp_size) {
1187 	    warnx(
1188 	"WARNING: adjusting size of partition %d from %u to %u\n\
1189     to end on a cylinder boundary",
1190 		    partition, (u_int)partp->dp_size, (u_int)adj_size);
1191 	    partp->dp_size = adj_size;
1192 	}
1193 		if (partp->dp_size == 0) {
1194 	    warnx("ERROR line %d: size of partition %d is zero",
1195 		    current_line_number, partition);
1196 	    break;
1197 	}
1198 
1199 	dos(partp);
1200 	status = 1;
1201 	break;
1202     }
1203     return (status);
1204 }
1205 
1206 
1207 static int
1208 process_active(CMD *command)
1209 {
1210     int				status = 0, partition, i;
1211     struct dos_partition	*partp;
1212 
1213 	while (1) {
1214 	active_processed = 1;
1215 		if (command->n_args != 1) {
1216 	    warnx("ERROR line %d: incorrect number of active args",
1217 		    current_line_number);
1218 	    status = 0;
1219 	    break;
1220 	}
1221 	partition = command->args[0].arg_val;
1222 		if (partition < 1 || partition > 4) {
1223 	    warnx("ERROR line %d: invalid partition number %d",
1224 		    current_line_number, partition);
1225 	    break;
1226 	}
1227 	/*
1228 	 * Reset active partition
1229 	 */
1230 	partp = ((struct dos_partition *) &mboot.parts);
1231 	for (i = 0; i < NDOSPART; i++)
1232 	    partp[i].dp_flag = 0;
1233 	partp[partition-1].dp_flag = ACTIVE;
1234 
1235 	status = 1;
1236 	break;
1237     }
1238     return (status);
1239 }
1240 
1241 
1242 static int
1243 process_line(char *line)
1244 {
1245     CMD		command;
1246     int		status = 1;
1247 
1248 	while (1) {
1249 	parse_config_line(line, &command);
1250 		switch (command.cmd) {
1251 	case 0:
1252 	    /*
1253 	     * Comment or blank line
1254 	     */
1255 	    break;
1256 	case 'g':
1257 	    /*
1258 	     * Set geometry
1259 	     */
1260 	    status = process_geometry(&command);
1261 	    break;
1262 	case 'p':
1263 	    status = process_partition(&command);
1264 	    break;
1265 	case 'a':
1266 	    status = process_active(&command);
1267 	    break;
1268 	default:
1269 	    status = 0;
1270 	    break;
1271 	}
1272 	break;
1273     }
1274     return (status);
1275 }
1276 
1277 
1278 static int
1279 read_config(char *config_file)
1280 {
1281     FILE	*fp = NULL;
1282     int		status = 1;
1283     char	buf[1010];
1284 
1285 	while (1) {
1286 		if (strcmp(config_file, "-") != 0) {
1287 	    /*
1288 	     * We're not reading from stdin
1289 	     */
1290 			if ((fp = fopen(config_file, "r")) == NULL) {
1291 		status = 0;
1292 		break;
1293 	    }
1294 		} else {
1295 	    fp = stdin;
1296 	}
1297 	current_line_number = 0;
1298 		while (!feof(fp)) {
1299 	    if (fgets(buf, sizeof(buf), fp) == NULL)
1300 		break;
1301 	    ++current_line_number;
1302 	    status = process_line(buf);
1303 	    if (status == 0)
1304 		break;
1305 	    }
1306 	break;
1307     }
1308 	if (fp) {
1309 	/*
1310 	 * It doesn't matter if we're reading from stdin, as we've reached EOF
1311 	 */
1312 	fclose(fp);
1313     }
1314     return (status);
1315 }
1316 
1317 
1318 static void
1319 reset_boot(void)
1320 {
1321     int				i;
1322     struct dos_partition	*partp;
1323 
1324     init_boot();
1325 	for (i = 0; i < 4; ++i) {
1326 	partp = ((struct dos_partition *) &mboot.parts) + i;
1327 	bzero((char *)partp, sizeof (struct dos_partition));
1328     }
1329 }
1330 
1331 static int
1332 sanitize_partition(struct dos_partition *partp)
1333 {
1334     u_int32_t			prev_head_boundary, prev_cyl_boundary;
1335     u_int32_t			max_end, size, start;
1336 
1337     start = partp->dp_start;
1338     size = partp->dp_size;
1339     max_end = start + size;
1340     /* Only allow a zero size if the partition is being marked unused. */
1341     if (size == 0) {
1342 	if (start == 0 && partp->dp_typ == 0)
1343 	    return (1);
1344 	warnx("ERROR: size of partition is zero");
1345 	return (0);
1346     }
1347     /* Return if no adjustment is necessary. */
1348     if (start % dos_sectors == 0 && (start + size) % dos_sectors == 0)
1349 	return (1);
1350 
1351     if (start == 0) {
1352 	    warnx("WARNING: partition overlaps with partition table");
1353 	    if (ok("Correct this automatically?"))
1354 		    start = dos_sectors;
1355     }
1356     if (start % dos_sectors != 0)
1357 	warnx("WARNING: partition does not start on a head boundary");
1358     if ((start  +size) % dos_sectors != 0)
1359 	warnx("WARNING: partition does not end on a cylinder boundary");
1360     warnx("WARNING: this may confuse the BIOS or some operating systems");
1361     if (!ok("Correct this automatically?"))
1362 	return (1);
1363 
1364     /*
1365      * Adjust start upwards, if necessary, to fall on a head boundary.
1366      */
1367     if (start % dos_sectors != 0) {
1368 	prev_head_boundary = start / dos_sectors * dos_sectors;
1369 	if (max_end < dos_sectors ||
1370 	    prev_head_boundary >= max_end - dos_sectors) {
1371 	    /*
1372 	     * Can't go past end of partition
1373 	     */
1374 	    warnx(
1375     "ERROR: unable to adjust start of partition to fall on a head boundary");
1376 	    return (0);
1377         }
1378 	start = prev_head_boundary + dos_sectors;
1379     }
1380 
1381     /*
1382      * Adjust size downwards, if necessary, to fall on a cylinder
1383      * boundary.
1384      */
1385     prev_cyl_boundary = ((start + size) / dos_cylsecs) * dos_cylsecs;
1386     if (prev_cyl_boundary > start)
1387 	size = prev_cyl_boundary - start;
1388     else {
1389 	warnx("ERROR: could not adjust partition to start on a head boundary\n\
1390     and end on a cylinder boundary.");
1391 	return (0);
1392     }
1393 
1394     /* Finally, commit any changes to partp and return. */
1395     if (start != partp->dp_start) {
1396 	warnx("WARNING: adjusting start offset of partition to %u",
1397 	    (u_int)start);
1398 	partp->dp_start = start;
1399     }
1400     if (size != partp->dp_size) {
1401 	warnx("WARNING: adjusting size of partition to %u", (u_int)size);
1402 	partp->dp_size = size;
1403     }
1404 
1405     return (1);
1406 }
1407 
1408 /*
1409  * Try figuring out the root device's canonical disk name.
1410  * The following choices are considered:
1411  *   /dev/ad0s1a     => /dev/ad0
1412  *   /dev/da0a       => /dev/da0
1413  *   /dev/vinum/root => /dev/vinum/root
1414  */
1415 static char *
1416 get_rootdisk(void)
1417 {
1418 	struct statfs rootfs;
1419 	regex_t re;
1420 #define NMATCHES 2
1421 	regmatch_t rm[NMATCHES];
1422 	char *s;
1423 	int rv;
1424 
1425 	if (statfs("/", &rootfs) == -1)
1426 		err(1, "statfs(\"/\")");
1427 
1428 	if ((rv = regcomp(&re, "^(/dev/[a-z/]+[0-9]+)([sp][0-9]+)?[a-h]?$",
1429 		    REG_EXTENDED)) != 0)
1430 		errx(1, "regcomp() failed (%d)", rv);
1431 	if ((rv = regexec(&re, rootfs.f_mntfromname, NMATCHES, rm, 0)) != 0)
1432 		errx(1,
1433 "mounted root fs resource doesn't match expectations (regexec returned %d)",
1434 		    rv);
1435 	if ((s = malloc(rm[1].rm_eo - rm[1].rm_so + 1)) == NULL)
1436 		errx(1, "out of memory");
1437 	memcpy(s, rootfs.f_mntfromname + rm[1].rm_so,
1438 	    rm[1].rm_eo - rm[1].rm_so);
1439 	s[rm[1].rm_eo - rm[1].rm_so] = 0;
1440 
1441 	return s;
1442 }
1443