xref: /freebsd/sbin/fdisk/fdisk.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
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 *bootinst;  /* boot code */
78 	off_t bootinst_size;
79 	struct	dos_partition parts[NDOSPART];
80 };
81 
82 static struct mboot mboot;
83 static int fd;
84 
85 #define ACTIVE 0x80
86 
87 static uint dos_cyls;
88 static uint dos_heads;
89 static uint dos_sectors;
90 static uint dos_cylsecs;
91 
92 #define DOSSECT(s,c) ((s & 0x3f) | ((c >> 2) & 0xc0))
93 #define DOSCYL(c)	(c & 0xff)
94 
95 #define MAX_ARGS	10
96 
97 static int	current_line_number;
98 
99 static int	geom_processed = 0;
100 static int	part_processed = 0;
101 static int	active_processed = 0;
102 
103 typedef struct cmd {
104     char		cmd;
105     int			n_args;
106     struct arg {
107 	char	argtype;
108 	int	arg_val;
109     }			args[MAX_ARGS];
110 } CMD;
111 
112 static int B_flag  = 0;		/* replace boot code */
113 static int I_flag  = 0;		/* use entire disk for FreeBSD */
114 static int a_flag  = 0;		/* set active partition */
115 static char *b_flag = NULL;	/* path to boot code */
116 static int i_flag  = 0;		/* replace partition data */
117 static int q_flag  = 0;		/* Be quiet */
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 /*
126  * A list of partition types, probably outdated.
127  */
128 static const char *const part_types[256] = {
129 	[0x00] = "unused",
130 	[0x01] = "Primary DOS with 12 bit FAT",
131 	[0x02] = "XENIX / file system",
132 	[0x03] = "XENIX /usr file system",
133 	[0x04] = "Primary DOS with 16 bit FAT (< 32MB)",
134 	[0x05] = "Extended DOS",
135 	[0x06] = "Primary DOS, 16 bit FAT (>= 32MB)",
136 	[0x07] = "NTFS, OS/2 HPFS, QNX-2 (16 bit) or Advanced UNIX",
137 	[0x08] = "AIX file system or SplitDrive",
138 	[0x09] = "AIX boot partition or Coherent",
139 	[0x0A] = "OS/2 Boot Manager, OPUS or Coherent swap",
140 	[0x0B] = "DOS or Windows 95 with 32 bit FAT",
141 	[0x0C] = "DOS or Windows 95 with 32 bit FAT (LBA)",
142 	[0x0E] = "Primary 'big' DOS (>= 32MB, LBA)",
143 	[0x0F] = "Extended DOS (LBA)",
144 	[0x10] = "OPUS",
145 	[0x11] = "OS/2 BM: hidden DOS with 12-bit FAT",
146 	[0x12] = "Compaq diagnostics",
147 	[0x14] = "OS/2 BM: hidden DOS with 16-bit FAT (< 32MB)",
148 	[0x16] = "OS/2 BM: hidden DOS with 16-bit FAT (>= 32MB)",
149 	[0x17] = "OS/2 BM: hidden IFS (e.g. HPFS)",
150 	[0x18] = "AST Windows swapfile",
151 	[0x1b] = "ASUS Recovery partition (NTFS)",
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 	[0xDE] = "DELL Utilities - FAT filesystem",
207 	[0xE1] = "DOS access or SpeedStor with 12-bit FAT extended partition",
208 	[0xE3] = "DOS R/O or SpeedStor",
209 	[0xE4] = "SpeedStor with 16-bit FAT extended partition < 1024 cyl.",
210 	[0xEB] = "BeOS file system",
211 	[0xEE] = "EFI GPT",
212 	[0xEF] = "EFI System Partition",
213 	[0xF1] = "SpeedStor",
214 	[0xF2] = "DOS 3.3+ Secondary",
215 	[0xF4] = "SpeedStor large partition",
216 	[0xFE] = "SpeedStor >1024 cyl. or LANstep",
217 	[0xFF] = "Xenix bad blocks table",
218 };
219 
220 static const char *
221 get_type(int t)
222 {
223 	const char *ret;
224 
225 	ret = (t >= 0 && t <= 255) ? part_types[t] : NULL;
226 	return ret ? ret : "unknown";
227 }
228 
229 
230 static void print_s0(void);
231 static void print_part(const struct dos_partition *);
232 static void init_sector0(unsigned long start);
233 static void init_boot(void);
234 static void change_part(int i);
235 static void print_params(void);
236 static void change_active(int which);
237 static void change_code(void);
238 static void get_params_to_use(void);
239 static char *get_rootdisk(void);
240 static void dos(struct dos_partition *partp);
241 static int open_disk(int flag);
242 static ssize_t read_disk(off_t sector, void *buf);
243 static int write_disk(off_t sector, void *buf);
244 static int get_params(void);
245 static int read_s0(void);
246 static int write_s0(void);
247 static int ok(const char *str);
248 static int decimal(const char *str, int *num, int deflt);
249 static int read_config(char *config_file);
250 static void reset_boot(void);
251 static int sanitize_partition(struct dos_partition *);
252 static void usage(void);
253 
254 int
255 main(int argc, char *argv[])
256 {
257 	int	c, i;
258 	int	partition = -1;
259 	struct	dos_partition *partp;
260 
261 	while ((c = getopt(argc, argv, "BIab:f:ipqstuv1234")) != -1)
262 		switch (c) {
263 		case 'B':
264 			B_flag = 1;
265 			break;
266 		case 'I':
267 			I_flag = 1;
268 			break;
269 		case 'a':
270 			a_flag = 1;
271 			break;
272 		case 'b':
273 			b_flag = optarg;
274 			break;
275 		case 'f':
276 			f_flag = optarg;
277 			break;
278 		case 'i':
279 			i_flag = 1;
280 			break;
281 		case 'p':
282 			print_config_flag = 1;
283 			break;
284 		case 'q':
285 			q_flag = 1;
286 			break;
287 		case 's':
288 			s_flag = 1;
289 			break;
290 		case 't':
291 			t_flag = 1;
292 			break;
293 		case 'u':
294 			u_flag = 1;
295 			break;
296 		case 'v':
297 			v_flag = 1;
298 			break;
299 		case '1':
300 		case '2':
301 		case '3':
302 		case '4':
303 			partition = c - '0';
304 			break;
305 		default:
306 			usage();
307 		}
308 	if (f_flag || i_flag)
309 		u_flag = 1;
310 	if (t_flag)
311 		v_flag = 1;
312 	argc -= optind;
313 	argv += optind;
314 
315 	if (argc == 0) {
316 		disk = get_rootdisk();
317 	} else {
318 		disk = g_device_path(argv[0]);
319 		if (disk == NULL)
320 			err(1, "unable to get correct path for %s", argv[0]);
321 	}
322 	if (open_disk(u_flag) < 0)
323 		err(1, "cannot open disk %s", disk);
324 
325 	/* (abu)use mboot.bootinst to probe for the sector size */
326 	if ((mboot.bootinst = malloc(MAX_SEC_SIZE)) == NULL)
327 		err(1, "cannot allocate buffer to determine disk sector size");
328 	if (read_disk(0, mboot.bootinst) == -1)
329 		errx(1, "could not detect sector size");
330 	free(mboot.bootinst);
331 	mboot.bootinst = NULL;
332 
333 	if (print_config_flag) {
334 		if (read_s0())
335 			err(1, "read_s0");
336 
337 		printf("# %s\n", disk);
338 		printf("g c%d h%d s%d\n", dos_cyls, dos_heads, dos_sectors);
339 
340 		for (i = 0; i < NDOSPART; i++) {
341 			partp = &mboot.parts[i];
342 
343 			if (partp->dp_start == 0 && partp->dp_size == 0)
344 				continue;
345 
346 			printf("p %d 0x%02x %lu %lu\n", i + 1, partp->dp_typ,
347 			    (u_long)partp->dp_start, (u_long)partp->dp_size);
348 
349 			/* Fill flags for the partition. */
350 			if (partp->dp_flag & 0x80)
351 				printf("a %d\n", i + 1);
352 		}
353 		exit(0);
354 	}
355 	if (s_flag) {
356 		if (read_s0())
357 			err(1, "read_s0");
358 		printf("%s: %d cyl %d hd %d sec\n", disk, dos_cyls, dos_heads,
359 		    dos_sectors);
360 		printf("Part  %11s %11s Type Flags\n", "Start", "Size");
361 		for (i = 0; i < NDOSPART; i++) {
362 			partp = &mboot.parts[i];
363 			if (partp->dp_start == 0 && partp->dp_size == 0)
364 				continue;
365 			printf("%4d: %11lu %11lu 0x%02x 0x%02x\n", i + 1,
366 			    (u_long) partp->dp_start,
367 			    (u_long) partp->dp_size, partp->dp_typ,
368 			    partp->dp_flag);
369 		}
370 		exit(0);
371 	}
372 
373 	printf("******* Working on device %s *******\n",disk);
374 
375 	if (I_flag) {
376 		read_s0();
377 		reset_boot();
378 		partp = &mboot.parts[0];
379 		partp->dp_typ = DOSPTYP_386BSD;
380 		partp->dp_flag = ACTIVE;
381 		partp->dp_start = dos_sectors;
382 		partp->dp_size = (disksecs / dos_cylsecs) * dos_cylsecs -
383 		    dos_sectors;
384 		dos(partp);
385 		if (v_flag)
386 			print_s0();
387 		if (!t_flag)
388 			write_s0();
389 		exit(0);
390 	}
391 	if (f_flag) {
392 	    if (read_s0() || i_flag)
393 		reset_boot();
394 	    if (!read_config(f_flag))
395 		exit(1);
396 	    if (v_flag)
397 		print_s0();
398 	    if (!t_flag)
399 		write_s0();
400 	} else {
401 	    if(u_flag)
402 		get_params_to_use();
403 	    else
404 		print_params();
405 
406 	    if (read_s0())
407 		init_sector0(dos_sectors);
408 
409 	    printf("Media sector size is %d\n", secsize);
410 	    printf("Warning: BIOS sector numbering starts with sector 1\n");
411 	    printf("Information from DOS bootblock is:\n");
412 	    if (partition == -1)
413 		for (i = 1; i <= NDOSPART; i++)
414 		    change_part(i);
415 	    else
416 		change_part(partition);
417 
418 	    if (u_flag || a_flag)
419 		change_active(partition);
420 
421 	    if (B_flag)
422 		change_code();
423 
424 	    if (u_flag || a_flag || B_flag) {
425 		if (!t_flag) {
426 		    printf("\nWe haven't changed the partition table yet.  ");
427 		    printf("This is your last chance.\n");
428 		}
429 		print_s0();
430 		if (!t_flag) {
431 		    if (ok("Should we write new partition table?"))
432 			write_s0();
433 		} else {
434 		    printf("\n-t flag specified -- partition table not written.\n");
435 		}
436 	    }
437 	}
438 
439 	exit(0);
440 }
441 
442 static void
443 usage()
444 {
445 	fprintf(stderr, "%s%s",
446 		"usage: fdisk [-BIaipqstu] [-b bootcode] [-1234] [disk]\n",
447  		"       fdisk -f configfile [-itv] [disk]\n");
448         exit(1);
449 }
450 
451 static void
452 print_s0(void)
453 {
454 	int	i;
455 
456 	print_params();
457 	printf("Information from DOS bootblock is:\n");
458 	for (i = 1; i <= NDOSPART; i++) {
459 		printf("%d: ", i);
460 		print_part(&mboot.parts[i - 1]);
461 	}
462 }
463 
464 static struct dos_partition mtpart;
465 
466 static void
467 print_part(const struct dos_partition *partp)
468 {
469 	u_int64_t part_mb;
470 
471 	if (!bcmp(partp, &mtpart, sizeof (struct dos_partition))) {
472 		printf("<UNUSED>\n");
473 		return;
474 	}
475 	/*
476 	 * Be careful not to overflow.
477 	 */
478 	part_mb = partp->dp_size;
479 	part_mb *= secsize;
480 	part_mb /= (1024 * 1024);
481 	printf("sysid %d (%#04x),(%s)\n", partp->dp_typ, partp->dp_typ,
482 	    get_type(partp->dp_typ));
483 	printf("    start %lu, size %lu (%ju Meg), flag %x%s\n",
484 		(u_long)partp->dp_start,
485 		(u_long)partp->dp_size,
486 		(uintmax_t)part_mb,
487 		partp->dp_flag,
488 		partp->dp_flag == ACTIVE ? " (active)" : "");
489 	printf("\tbeg: cyl %d/ head %d/ sector %d;\n\tend: cyl %d/ head %d/ sector %d\n"
490 		,DPCYL(partp->dp_scyl, partp->dp_ssect)
491 		,partp->dp_shd
492 		,DPSECT(partp->dp_ssect)
493 		,DPCYL(partp->dp_ecyl, partp->dp_esect)
494 		,partp->dp_ehd
495 		,DPSECT(partp->dp_esect));
496 }
497 
498 
499 static void
500 init_boot(void)
501 {
502 #ifndef __ia64__
503 	const char *fname;
504 	int fdesc, n;
505 	struct stat sb;
506 
507 	fname = b_flag ? b_flag : "/boot/mbr";
508 	if ((fdesc = open(fname, O_RDONLY)) == -1 ||
509 	    fstat(fdesc, &sb) == -1)
510 		err(1, "%s", fname);
511 	if ((mboot.bootinst_size = sb.st_size) % secsize != 0)
512 		errx(1, "%s: length must be a multiple of sector size", fname);
513 	if (mboot.bootinst != NULL)
514 		free(mboot.bootinst);
515 	if ((mboot.bootinst = malloc(mboot.bootinst_size = sb.st_size)) == NULL)
516 		errx(1, "%s: unable to allocate read buffer", fname);
517 	if ((n = read(fdesc, mboot.bootinst, mboot.bootinst_size)) == -1 ||
518 	    close(fdesc))
519 		err(1, "%s", fname);
520 	if (n != mboot.bootinst_size)
521 		errx(1, "%s: short read", fname);
522 #else
523 	if (mboot.bootinst != NULL)
524 		free(mboot.bootinst);
525 	mboot.bootinst_size = secsize;
526 	if ((mboot.bootinst = malloc(mboot.bootinst_size)) == NULL)
527 		errx(1, "unable to allocate boot block buffer");
528 	memset(mboot.bootinst, 0, mboot.bootinst_size);
529 	le16enc(&mboot.bootinst[DOSMAGICOFFSET], DOSMAGIC);
530 #endif
531 }
532 
533 
534 static void
535 init_sector0(unsigned long start)
536 {
537 	struct dos_partition *partp = &mboot.parts[0];
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 = &mboot.parts[i - 1];
556 
557     printf("The data for partition %d is:\n", i);
558     print_part(partp);
559 
560     if (u_flag && ok("Do you want to change it?")) {
561 	int tmp;
562 
563 	if (i_flag) {
564 	    bzero(partp, sizeof (*partp));
565 	    if (i == 1) {
566 		init_sector0(1);
567 		printf("\nThe static data for the slice 1 has been reinitialized to:\n");
568 		print_part(partp);
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(partp);
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_cyls > 1023 || dos_heads > 255 || dos_sectors > 63)
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(struct dos_partition *partp)
694 {
695 	int cy, sec;
696 	u_int32_t end;
697 
698 	if (partp->dp_typ == 0 && partp->dp_start == 0 && partp->dp_size == 0) {
699 		memcpy(partp, &mtpart, sizeof(*partp));
700 		return;
701 	}
702 
703 	/* Start c/h/s. */
704 	partp->dp_shd = partp->dp_start % dos_cylsecs / dos_sectors;
705 	cy = partp->dp_start / dos_cylsecs;
706 	sec = partp->dp_start % dos_sectors + 1;
707 	partp->dp_scyl = DOSCYL(cy);
708 	partp->dp_ssect = DOSSECT(sec, cy);
709 
710 	/* End c/h/s. */
711 	end = partp->dp_start + partp->dp_size - 1;
712 	partp->dp_ehd = end % dos_cylsecs / dos_sectors;
713 	cy = end / dos_cylsecs;
714 	sec = end % dos_sectors + 1;
715 	partp->dp_ecyl = DOSCYL(cy);
716 	partp->dp_esect = DOSSECT(sec, cy);
717 }
718 
719 static int
720 open_disk(int flag)
721 {
722 	int rwmode;
723 
724 	/* Write mode if one of these flags are set. */
725 	rwmode = (a_flag || I_flag || B_flag || flag);
726 	fd = g_open(disk, rwmode);
727 	/* If the mode fails, try read-only if we didn't. */
728 	if (fd == -1 && errno == EPERM && rwmode)
729 		fd = g_open(disk, 0);
730 	if (fd == -1 && errno == ENXIO)
731 		return -2;
732 	if (fd == -1) {
733 		warnx("can't open device %s", disk);
734 		return -1;
735 	}
736 	if (get_params() == -1) {
737 		warnx("can't get disk parameters on %s", disk);
738 		return -1;
739 	}
740 	return fd;
741 }
742 
743 static ssize_t
744 read_disk(off_t sector, void *buf)
745 {
746 
747 	lseek(fd, (sector * 512), 0);
748 	if (secsize == 0)
749 		for (secsize = MIN_SEC_SIZE; secsize <= MAX_SEC_SIZE;
750 		     secsize *= 2) {
751 			/* try the read */
752 			int size = read(fd, buf, secsize);
753 			if (size == secsize)
754 				/* it worked so return */
755 				return secsize;
756 		}
757 	else
758 		return read(fd, buf, secsize);
759 
760 	/* we failed to read at any of the sizes */
761 	return -1;
762 }
763 
764 static int
765 write_disk(off_t sector, void *buf)
766 {
767 	int error;
768 	struct gctl_req *grq;
769 	const char *errmsg;
770 	char fbuf[BUFSIZ], *pname;
771 	int i, fdw;
772 
773 	grq = gctl_get_handle();
774 	gctl_ro_param(grq, "verb", -1, "write MBR");
775 	gctl_ro_param(grq, "class", -1, "MBR");
776 	pname = g_providername(fd);
777 	if (pname == NULL) {
778 		warn("Error getting providername for %s", disk);
779 		return (-1);
780 	}
781 	gctl_ro_param(grq, "geom", -1, pname);
782 	gctl_ro_param(grq, "data", secsize, buf);
783 	errmsg = gctl_issue(grq);
784 	free(pname);
785 	if (errmsg == NULL) {
786 		gctl_free(grq);
787 		return(0);
788 	}
789 	if (!q_flag)	/* GEOM errors are benign, not all devices supported */
790 		warnx("%s", errmsg);
791 	gctl_free(grq);
792 
793 	error = pwrite(fd, buf, secsize, (sector * 512));
794 	if (error == secsize)
795 		return (0);
796 
797 	for (i = 1; i < 5; i++) {
798 		sprintf(fbuf, "%ss%d", disk, i);
799 		fdw = open(fbuf, O_RDWR, 0);
800 		if (fdw < 0)
801 			continue;
802 		error = ioctl(fdw, DIOCSMBR, buf);
803 		close(fdw);
804 		if (error == 0)
805 			return (0);
806 	}
807 	warnx("Failed to write sector zero");
808 	return(EINVAL);
809 }
810 
811 static int
812 get_params()
813 {
814 	int error;
815 	u_int u;
816 	off_t o;
817 
818 	error = ioctl(fd, DIOCGFWSECTORS, &u);
819 	if (error == 0)
820 		sectors = dos_sectors = u;
821 	else
822 		sectors = dos_sectors = 63;
823 
824 	error = ioctl(fd, DIOCGFWHEADS, &u);
825 	if (error == 0)
826 		heads = dos_heads = u;
827 	else
828 		heads = dos_heads = 255;
829 
830 	dos_cylsecs = cylsecs = heads * sectors;
831 	disksecs = cyls * heads * sectors;
832 
833 	u = g_sectorsize(fd);
834 	if (u <= 0)
835 		return (-1);
836 
837 	o = g_mediasize(fd);
838 	if (o < 0)
839 		return (-1);
840 	disksecs = o / u;
841 	cyls = dos_cyls = o / (u * dos_heads * dos_sectors);
842 
843 	return (disksecs);
844 }
845 
846 static int
847 read_s0()
848 {
849 	int i;
850 
851 	mboot.bootinst_size = secsize;
852 	if (mboot.bootinst != NULL)
853 		free(mboot.bootinst);
854 	if ((mboot.bootinst = malloc(mboot.bootinst_size)) == NULL) {
855 		warnx("unable to allocate buffer to read fdisk "
856 		      "partition table");
857 		return -1;
858 	}
859 	if (read_disk(0, mboot.bootinst) == -1) {
860 		warnx("can't read fdisk partition table");
861 		return -1;
862 	}
863 	if (le16dec(&mboot.bootinst[DOSMAGICOFFSET]) != DOSMAGIC) {
864 		warnx("invalid fdisk partition table found");
865 		/* So should we initialize things */
866 		return -1;
867 	}
868 	for (i = 0; i < NDOSPART; i++)
869 		dos_partition_dec(
870 		    &mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
871 		    &mboot.parts[i]);
872 	return 0;
873 }
874 
875 static int
876 write_s0()
877 {
878 	int	sector, i;
879 
880 	if (iotest) {
881 		print_s0();
882 		return 0;
883 	}
884 	for(i = 0; i < NDOSPART; i++)
885 		dos_partition_enc(&mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
886 		    &mboot.parts[i]);
887 	le16enc(&mboot.bootinst[DOSMAGICOFFSET], DOSMAGIC);
888 	for(sector = 0; sector < mboot.bootinst_size / secsize; sector++)
889 		if (write_disk(sector,
890 			       &mboot.bootinst[sector * secsize]) == -1) {
891 			warn("can't write fdisk partition table");
892 			return -1;
893 		}
894 	return(0);
895 }
896 
897 
898 static int
899 ok(const char *str)
900 {
901 	printf("%s [n] ", str);
902 	fflush(stdout);
903 	if (fgets(lbuf, LBUF, stdin) == NULL)
904 		exit(1);
905 	lbuf[strlen(lbuf)-1] = 0;
906 
907 	if (*lbuf &&
908 		(!strcmp(lbuf, "yes") || !strcmp(lbuf, "YES") ||
909 		 !strcmp(lbuf, "y") || !strcmp(lbuf, "Y")))
910 		return 1;
911 	else
912 		return 0;
913 }
914 
915 static int
916 decimal(const char *str, int *num, int deflt)
917 {
918 	int acc = 0, c;
919 	char *cp;
920 
921 	while (1) {
922 		printf("Supply a decimal value for \"%s\" [%d] ", str, deflt);
923 		fflush(stdout);
924 		if (fgets(lbuf, LBUF, stdin) == NULL)
925 			exit(1);
926 		lbuf[strlen(lbuf)-1] = 0;
927 
928 		if (!*lbuf)
929 			return 0;
930 
931 		cp = lbuf;
932 		while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
933 		if (!c)
934 			return 0;
935 		while ((c = *cp++)) {
936 			if (c <= '9' && c >= '0')
937 				acc = acc * 10 + c - '0';
938 			else
939 				break;
940 		}
941 		if (c == ' ' || c == '\t')
942 			while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
943 		if (!c) {
944 			*num = acc;
945 			return 1;
946 		} else
947 			printf("%s is an invalid decimal number.  Try again.\n",
948 				lbuf);
949 	}
950 
951 }
952 
953 
954 static void
955 parse_config_line(char *line, CMD *command)
956 {
957     char	*cp, *end;
958 
959     cp = line;
960     while (1) {
961 	memset(command, 0, sizeof(*command));
962 
963 	while (isspace(*cp)) ++cp;
964 	if (*cp == '\0' || *cp == '#')
965 	    break;
966 	command->cmd = *cp++;
967 
968 	/*
969 	 * Parse args
970 	 */
971 	    while (1) {
972 	    while (isspace(*cp)) ++cp;
973 	    if (*cp == '#')
974 		break;		/* found comment */
975 	    if (isalpha(*cp))
976 		command->args[command->n_args].argtype = *cp++;
977 	    if (!isdigit(*cp))
978 		break;		/* assume end of line */
979 	    end = NULL;
980 	    command->args[command->n_args].arg_val = strtol(cp, &end, 0);
981 	    if (cp == end)
982 		break;		/* couldn't parse number */
983 	    cp = end;
984 	    command->n_args++;
985 	}
986 	break;
987     }
988 }
989 
990 
991 static int
992 process_geometry(CMD *command)
993 {
994     int		status = 1, i;
995 
996     while (1) {
997 	geom_processed = 1;
998 	    if (part_processed) {
999 	    warnx(
1000 	"ERROR line %d: the geometry specification line must occur before\n\
1001     all partition specifications",
1002 		    current_line_number);
1003 	    status = 0;
1004 	    break;
1005 	}
1006 	    if (command->n_args != 3) {
1007 	    warnx("ERROR line %d: incorrect number of geometry args",
1008 		    current_line_number);
1009 	    status = 0;
1010 	    break;
1011 	}
1012 	    dos_cyls = 0;
1013 	    dos_heads = 0;
1014 	    dos_sectors = 0;
1015 	    for (i = 0; i < 3; ++i) {
1016 		    switch (command->args[i].argtype) {
1017 	    case 'c':
1018 		dos_cyls = command->args[i].arg_val;
1019 		break;
1020 	    case 'h':
1021 		dos_heads = command->args[i].arg_val;
1022 		break;
1023 	    case 's':
1024 		dos_sectors = command->args[i].arg_val;
1025 		break;
1026 	    default:
1027 		warnx(
1028 		"ERROR line %d: unknown geometry arg type: '%c' (0x%02x)",
1029 			current_line_number, command->args[i].argtype,
1030 			command->args[i].argtype);
1031 		status = 0;
1032 		break;
1033 	    }
1034 	}
1035 	if (status == 0)
1036 	    break;
1037 
1038 	dos_cylsecs = dos_heads * dos_sectors;
1039 
1040 	/*
1041 	 * Do sanity checks on parameter values
1042 	 */
1043 	    if (dos_cyls == 0) {
1044 	    warnx("ERROR line %d: number of cylinders not specified",
1045 		    current_line_number);
1046 	    status = 0;
1047 	}
1048 	    if (dos_cyls > 1024) {
1049 	    warnx(
1050 	"WARNING line %d: number of cylinders (%d) may be out-of-range\n\
1051     (must be within 1-1024 for normal BIOS operation, unless the entire disk\n\
1052     is dedicated to FreeBSD)",
1053 		    current_line_number, dos_cyls);
1054 	}
1055 
1056 	    if (dos_heads == 0) {
1057 	    warnx("ERROR line %d: number of heads not specified",
1058 		    current_line_number);
1059 	    status = 0;
1060 	    } else if (dos_heads > 256) {
1061 	    warnx("ERROR line %d: number of heads must be within (1-256)",
1062 		    current_line_number);
1063 	    status = 0;
1064 	}
1065 
1066 	    if (dos_sectors == 0) {
1067 	    warnx("ERROR line %d: number of sectors not specified",
1068 		    current_line_number);
1069 	    status = 0;
1070 	    } else if (dos_sectors > 63) {
1071 	    warnx("ERROR line %d: number of sectors must be within (1-63)",
1072 		    current_line_number);
1073 	    status = 0;
1074 	}
1075 
1076 	break;
1077     }
1078     return (status);
1079 }
1080 
1081 
1082 static int
1083 process_partition(CMD *command)
1084 {
1085     int				status = 0, partition;
1086     u_int32_t			prev_head_boundary, prev_cyl_boundary;
1087     u_int32_t			adj_size, max_end;
1088     struct dos_partition	*partp;
1089 
1090 	while (1) {
1091 	part_processed = 1;
1092 		if (command->n_args != 4) {
1093 	    warnx("ERROR line %d: incorrect number of partition args",
1094 		    current_line_number);
1095 	    break;
1096 	}
1097 	partition = command->args[0].arg_val;
1098 		if (partition < 1 || partition > 4) {
1099 	    warnx("ERROR line %d: invalid partition number %d",
1100 		    current_line_number, partition);
1101 	    break;
1102 	}
1103 	partp = &mboot.parts[partition - 1];
1104 	bzero(partp, sizeof (*partp));
1105 	partp->dp_typ = command->args[1].arg_val;
1106 	partp->dp_start = command->args[2].arg_val;
1107 	partp->dp_size = command->args[3].arg_val;
1108 	max_end = partp->dp_start + partp->dp_size;
1109 
1110 	if (partp->dp_typ == 0) {
1111 	    /*
1112 	     * Get out, the partition is marked as unused.
1113 	     */
1114 	    /*
1115 	     * Insure that it's unused.
1116 	     */
1117 	    bzero(partp, sizeof(*partp));
1118 	    status = 1;
1119 	    break;
1120 	}
1121 
1122 	/*
1123 	 * Adjust start upwards, if necessary, to fall on a head boundary.
1124 	 */
1125 		if (partp->dp_start % dos_sectors != 0) {
1126 	    prev_head_boundary = partp->dp_start / dos_sectors * dos_sectors;
1127 	    if (max_end < dos_sectors ||
1128 			    prev_head_boundary > max_end - dos_sectors) {
1129 		/*
1130 		 * Can't go past end of partition
1131 		 */
1132 		warnx(
1133 	"ERROR line %d: unable to adjust start of partition %d to fall on\n\
1134     a head boundary",
1135 			current_line_number, partition);
1136 		break;
1137 	    }
1138 	    warnx(
1139 	"WARNING: adjusting start offset of partition %d\n\
1140     from %u to %u, to fall on a head boundary",
1141 		    partition, (u_int)partp->dp_start,
1142 		    (u_int)(prev_head_boundary + dos_sectors));
1143 	    partp->dp_start = prev_head_boundary + dos_sectors;
1144 	}
1145 
1146 	/*
1147 	 * Adjust size downwards, if necessary, to fall on a cylinder
1148 	 * boundary.
1149 	 */
1150 	prev_cyl_boundary =
1151 	    ((partp->dp_start + partp->dp_size) / dos_cylsecs) * dos_cylsecs;
1152 	if (prev_cyl_boundary > partp->dp_start)
1153 	    adj_size = prev_cyl_boundary - partp->dp_start;
1154 		else {
1155 	    warnx(
1156 	"ERROR: could not adjust partition to start on a head boundary\n\
1157     and end on a cylinder boundary.");
1158 	    return (0);
1159 	}
1160 		if (adj_size != partp->dp_size) {
1161 	    warnx(
1162 	"WARNING: adjusting size of partition %d from %u to %u\n\
1163     to end on a cylinder boundary",
1164 		    partition, (u_int)partp->dp_size, (u_int)adj_size);
1165 	    partp->dp_size = adj_size;
1166 	}
1167 		if (partp->dp_size == 0) {
1168 	    warnx("ERROR line %d: size of partition %d is zero",
1169 		    current_line_number, partition);
1170 	    break;
1171 	}
1172 
1173 	dos(partp);
1174 	status = 1;
1175 	break;
1176     }
1177     return (status);
1178 }
1179 
1180 
1181 static int
1182 process_active(CMD *command)
1183 {
1184     int				status = 0, partition, i;
1185     struct dos_partition	*partp;
1186 
1187 	while (1) {
1188 	active_processed = 1;
1189 		if (command->n_args != 1) {
1190 	    warnx("ERROR line %d: incorrect number of active args",
1191 		    current_line_number);
1192 	    status = 0;
1193 	    break;
1194 	}
1195 	partition = command->args[0].arg_val;
1196 		if (partition < 1 || partition > 4) {
1197 	    warnx("ERROR line %d: invalid partition number %d",
1198 		    current_line_number, partition);
1199 	    break;
1200 	}
1201 	/*
1202 	 * Reset active partition
1203 	 */
1204 	partp = mboot.parts;
1205 	for (i = 0; i < NDOSPART; i++)
1206 	    partp[i].dp_flag = 0;
1207 	partp[partition-1].dp_flag = ACTIVE;
1208 
1209 	status = 1;
1210 	break;
1211     }
1212     return (status);
1213 }
1214 
1215 
1216 static int
1217 process_line(char *line)
1218 {
1219     CMD		command;
1220     int		status = 1;
1221 
1222 	while (1) {
1223 	parse_config_line(line, &command);
1224 		switch (command.cmd) {
1225 	case 0:
1226 	    /*
1227 	     * Comment or blank line
1228 	     */
1229 	    break;
1230 	case 'g':
1231 	    /*
1232 	     * Set geometry
1233 	     */
1234 	    status = process_geometry(&command);
1235 	    break;
1236 	case 'p':
1237 	    status = process_partition(&command);
1238 	    break;
1239 	case 'a':
1240 	    status = process_active(&command);
1241 	    break;
1242 	default:
1243 	    status = 0;
1244 	    break;
1245 	}
1246 	break;
1247     }
1248     return (status);
1249 }
1250 
1251 
1252 static int
1253 read_config(char *config_file)
1254 {
1255     FILE	*fp = NULL;
1256     int		status = 1;
1257     char	buf[1010];
1258 
1259 	while (1) {
1260 		if (strcmp(config_file, "-") != 0) {
1261 	    /*
1262 	     * We're not reading from stdin
1263 	     */
1264 			if ((fp = fopen(config_file, "r")) == NULL) {
1265 		status = 0;
1266 		break;
1267 	    }
1268 		} else {
1269 	    fp = stdin;
1270 	}
1271 	current_line_number = 0;
1272 		while (!feof(fp)) {
1273 	    if (fgets(buf, sizeof(buf), fp) == NULL)
1274 		break;
1275 	    ++current_line_number;
1276 	    status = process_line(buf);
1277 	    if (status == 0)
1278 		break;
1279 	    }
1280 	break;
1281     }
1282 	if (fp) {
1283 	/*
1284 	 * It doesn't matter if we're reading from stdin, as we've reached EOF
1285 	 */
1286 	fclose(fp);
1287     }
1288     return (status);
1289 }
1290 
1291 
1292 static void
1293 reset_boot(void)
1294 {
1295     int				i;
1296     struct dos_partition	*partp;
1297 
1298     init_boot();
1299     for (i = 0; i < 4; ++i) {
1300 	partp = &mboot.parts[i];
1301 	bzero(partp, sizeof(*partp));
1302     }
1303 }
1304 
1305 static int
1306 sanitize_partition(struct dos_partition *partp)
1307 {
1308     u_int32_t			prev_head_boundary, prev_cyl_boundary;
1309     u_int32_t			max_end, size, start;
1310 
1311     start = partp->dp_start;
1312     size = partp->dp_size;
1313     max_end = start + size;
1314     /* Only allow a zero size if the partition is being marked unused. */
1315     if (size == 0) {
1316 	if (start == 0 && partp->dp_typ == 0)
1317 	    return (1);
1318 	warnx("ERROR: size of partition is zero");
1319 	return (0);
1320     }
1321     /* Return if no adjustment is necessary. */
1322     if (start % dos_sectors == 0 && (start + size) % dos_sectors == 0)
1323 	return (1);
1324 
1325     if (start == 0) {
1326 	    warnx("WARNING: partition overlaps with partition table");
1327 	    if (ok("Correct this automatically?"))
1328 		    start = dos_sectors;
1329     }
1330     if (start % dos_sectors != 0)
1331 	warnx("WARNING: partition does not start on a head boundary");
1332     if ((start  +size) % dos_sectors != 0)
1333 	warnx("WARNING: partition does not end on a cylinder boundary");
1334     warnx("WARNING: this may confuse the BIOS or some operating systems");
1335     if (!ok("Correct this automatically?"))
1336 	return (1);
1337 
1338     /*
1339      * Adjust start upwards, if necessary, to fall on a head boundary.
1340      */
1341     if (start % dos_sectors != 0) {
1342 	prev_head_boundary = start / dos_sectors * dos_sectors;
1343 	if (max_end < dos_sectors ||
1344 	    prev_head_boundary >= max_end - dos_sectors) {
1345 	    /*
1346 	     * Can't go past end of partition
1347 	     */
1348 	    warnx(
1349     "ERROR: unable to adjust start of partition to fall on a head boundary");
1350 	    return (0);
1351         }
1352 	start = prev_head_boundary + dos_sectors;
1353     }
1354 
1355     /*
1356      * Adjust size downwards, if necessary, to fall on a cylinder
1357      * boundary.
1358      */
1359     prev_cyl_boundary = ((start + size) / dos_cylsecs) * dos_cylsecs;
1360     if (prev_cyl_boundary > start)
1361 	size = prev_cyl_boundary - start;
1362     else {
1363 	warnx("ERROR: could not adjust partition to start on a head boundary\n\
1364     and end on a cylinder boundary.");
1365 	return (0);
1366     }
1367 
1368     /* Finally, commit any changes to partp and return. */
1369     if (start != partp->dp_start) {
1370 	warnx("WARNING: adjusting start offset of partition to %u",
1371 	    (u_int)start);
1372 	partp->dp_start = start;
1373     }
1374     if (size != partp->dp_size) {
1375 	warnx("WARNING: adjusting size of partition to %u", (u_int)size);
1376 	partp->dp_size = size;
1377     }
1378 
1379     return (1);
1380 }
1381 
1382 /*
1383  * Try figuring out the root device's canonical disk name.
1384  * The following choices are considered:
1385  *   /dev/ad0s1a     => /dev/ad0
1386  *   /dev/da0a       => /dev/da0
1387  *   /dev/vinum/root => /dev/vinum/root
1388  */
1389 static char *
1390 get_rootdisk(void)
1391 {
1392 	struct statfs rootfs;
1393 	regex_t re;
1394 #define NMATCHES 2
1395 	regmatch_t rm[NMATCHES];
1396 	char *s;
1397 	int rv;
1398 
1399 	if (statfs("/", &rootfs) == -1)
1400 		err(1, "statfs(\"/\")");
1401 
1402 	if ((rv = regcomp(&re, "^(/dev/[a-z/]+[0-9]+)([sp][0-9]+)?[a-h]?$",
1403 		    REG_EXTENDED)) != 0)
1404 		errx(1, "regcomp() failed (%d)", rv);
1405 	if ((rv = regexec(&re, rootfs.f_mntfromname, NMATCHES, rm, 0)) != 0)
1406 		errx(1,
1407 "mounted root fs resource doesn't match expectations (regexec returned %d)",
1408 		    rv);
1409 	if ((s = malloc(rm[1].rm_eo - rm[1].rm_so + 1)) == NULL)
1410 		errx(1, "out of memory");
1411 	memcpy(s, rootfs.f_mntfromname + rm[1].rm_so,
1412 	    rm[1].rm_eo - rm[1].rm_so);
1413 	s[rm[1].rm_eo - rm[1].rm_so] = 0;
1414 
1415 	return s;
1416 }
1417