xref: /freebsd/sbin/fdisk/fdisk.c (revision 090e9752d7291db0c251a5576892e3bbbaea2479)
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 #include "fdisk_mbr_enc.h"
51 
52 static int iotest;
53 
54 #define NO_DISK_SECTORS ((u_int32_t)-1)
55 #define NO_TRACK_CYLINDERS 1023
56 #define NO_TRACK_HEADS 255
57 #define NO_TRACK_SECTORS 63
58 #define LBUF 100
59 static char lbuf[LBUF];
60 
61 /*
62  *
63  * Ported to 386bsd by Julian Elischer  Thu Oct 15 20:26:46 PDT 1992
64  *
65  * 14-Dec-89  Robert Baron (rvb) at Carnegie-Mellon University
66  *	Copyright (c) 1989	Robert. V. Baron
67  *	Created.
68  */
69 
70 #define Decimal(str, ans, tmp, maxval) if (decimal(str, &tmp, ans, maxval)) ans = tmp
71 
72 #define MAX_SEC_SIZE 65536	/* maximum sector size that is supported */
73 #define MIN_SEC_SIZE 512	/* the sector size to start sensing at */
74 static int secsize = 0;		/* the sensed sector size */
75 
76 static char *disk;
77 
78 static int cyls, sectors, heads, cylsecs;
79 static u_int32_t disksecs;
80 
81 struct mboot {
82 	unsigned char *bootinst;  /* boot code */
83 	off_t bootinst_size;
84 	struct	dos_partition parts[NDOSPART];
85 };
86 
87 static struct mboot mboot;
88 static int fd;
89 
90 #define ACTIVE 0x80
91 
92 static uint dos_cyls;
93 static uint dos_heads;
94 static uint dos_sectors;
95 static uint dos_cylsecs;
96 
97 #define DOSSECT(s,c) ((s & 0x3f) | ((c >> 2) & 0xc0))
98 #define DOSCYL(c)	(c & 0xff)
99 
100 #define MAX_ARGS	10
101 
102 static int	current_line_number;
103 
104 static int	geom_processed = 0;
105 static int	part_processed = 0;
106 static int	active_processed = 0;
107 
108 typedef struct cmd {
109     char		cmd;
110     int			n_args;
111     struct arg {
112 	char		argtype;
113 	unsigned long	arg_val;
114 	char *		arg_str;
115     }			args[MAX_ARGS];
116 } CMD;
117 
118 static int B_flag  = 0;		/* replace boot code */
119 static int I_flag  = 0;		/* use entire disk for FreeBSD */
120 static int a_flag  = 0;		/* set active partition */
121 static char *b_flag = NULL;	/* path to boot code */
122 static int i_flag  = 0;		/* replace partition data */
123 static int q_flag  = 0;		/* Be quiet */
124 static int u_flag  = 0;		/* update partition data */
125 static int s_flag  = 0;		/* Print a summary and exit */
126 static int t_flag  = 0;		/* test only */
127 static char *f_flag = NULL;	/* Read config info from file */
128 static int v_flag  = 0;		/* Be verbose */
129 static int print_config_flag = 0;
130 
131 /*
132  * A list of partition types, probably outdated.
133  */
134 static const char *const part_types[256] = {
135 	[0x00] = "unused",
136 	[0x01] = "Primary DOS with 12 bit FAT",
137 	[0x02] = "XENIX / file system",
138 	[0x03] = "XENIX /usr file system",
139 	[0x04] = "Primary DOS with 16 bit FAT (< 32MB)",
140 	[0x05] = "Extended DOS",
141 	[0x06] = "Primary DOS, 16 bit FAT (>= 32MB)",
142 	[0x07] = "NTFS, OS/2 HPFS, QNX-2 (16 bit) or Advanced UNIX",
143 	[0x08] = "AIX file system or SplitDrive",
144 	[0x09] = "AIX boot partition or Coherent",
145 	[0x0A] = "OS/2 Boot Manager, OPUS or Coherent swap",
146 	[0x0B] = "DOS or Windows 95 with 32 bit FAT",
147 	[0x0C] = "DOS or Windows 95 with 32 bit FAT (LBA)",
148 	[0x0E] = "Primary 'big' DOS (>= 32MB, LBA)",
149 	[0x0F] = "Extended DOS (LBA)",
150 	[0x10] = "OPUS",
151 	[0x11] = "OS/2 BM: hidden DOS with 12-bit FAT",
152 	[0x12] = "Compaq diagnostics",
153 	[0x14] = "OS/2 BM: hidden DOS with 16-bit FAT (< 32MB)",
154 	[0x16] = "OS/2 BM: hidden DOS with 16-bit FAT (>= 32MB)",
155 	[0x17] = "OS/2 BM: hidden IFS (e.g. HPFS)",
156 	[0x18] = "AST Windows swapfile",
157 	[0x1b] = "ASUS Recovery partition (NTFS)",
158 	[0x24] = "NEC DOS",
159 	[0x3C] = "PartitionMagic recovery",
160 	[0x39] = "plan9",
161 	[0x40] = "VENIX 286",
162 	[0x41] = "Linux/MINIX (sharing disk with DRDOS)",
163 	[0x42] = "SFS or Linux swap (sharing disk with DRDOS)",
164 	[0x43] = "Linux native (sharing disk with DRDOS)",
165 	[0x4D] = "QNX 4.2 Primary",
166 	[0x4E] = "QNX 4.2 Secondary",
167 	[0x4F] = "QNX 4.2 Tertiary",
168 	[0x50] = "DM (disk manager)",
169 	[0x51] = "DM6 Aux1 (or Novell)",
170 	[0x52] = "CP/M or Microport SysV/AT",
171 	[0x53] = "DM6 Aux3",
172 	[0x54] = "DM6",
173 	[0x55] = "EZ-Drive (disk manager)",
174 	[0x56] = "Golden Bow (disk manager)",
175 	[0x5c] = "Priam Edisk (disk manager)", /* according to S. Widlake */
176 	[0x61] = "SpeedStor",
177 	[0x63] = "System V/386 (such as ISC UNIX), GNU HURD or Mach",
178 	[0x64] = "Novell Netware/286 2.xx",
179 	[0x65] = "Novell Netware/386 3.xx",
180 	[0x6C] = "DragonFlyBSD",
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 file system",
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 	[0xAC] = "IBM JFS",
203 	[0xAF] = "HFS+",
204 	[0xB7] = "BSDI BSD/386 file system",
205 	[0xB8] = "BSDI BSD/386 swap",
206 	[0xBE] = "Solaris x86 boot",
207 	[0xBF] = "Solaris x86 (new)",
208 	[0xC1] = "DRDOS/sec with 12-bit FAT",
209 	[0xC4] = "DRDOS/sec with 16-bit FAT (< 32MB)",
210 	[0xC6] = "DRDOS/sec with 16-bit FAT (>= 32MB)",
211 	[0xC7] = "Syrinx",
212 	[0xDB] = "CP/M, Concurrent CP/M, Concurrent DOS or CTOS",
213 	[0xDE] = "DELL Utilities - FAT filesystem",
214 	[0xE1] = "DOS access or SpeedStor with 12-bit FAT extended partition",
215 	[0xE3] = "DOS R/O or SpeedStor",
216 	[0xE4] = "SpeedStor with 16-bit FAT extended partition < 1024 cyl.",
217 	[0xEB] = "BeOS file system",
218 	[0xEE] = "EFI GPT",
219 	[0xEF] = "EFI System Partition",
220 	[0xF1] = "SpeedStor",
221 	[0xF2] = "DOS 3.3+ Secondary",
222 	[0xF4] = "SpeedStor large partition",
223 	[0xFB] = "VMware VMFS",
224 	[0xFE] = "SpeedStor >1024 cyl. or LANstep",
225 	[0xFF] = "Xenix bad blocks table",
226 };
227 
228 static const char *
229 get_type(int t)
230 {
231 	const char *ret;
232 
233 	ret = (t >= 0 && t <= 255) ? part_types[t] : NULL;
234 	return ret ? ret : "unknown";
235 }
236 
237 
238 static int geom_class_available(const char *);
239 static void print_s0(void);
240 static void print_part(const struct dos_partition *);
241 static void init_sector0(unsigned long start);
242 static void init_boot(void);
243 static void change_part(int i);
244 static void print_params(void);
245 static void change_active(int which);
246 static void change_code(void);
247 static void get_params_to_use(void);
248 static char *get_rootdisk(void);
249 static void dos(struct dos_partition *partp);
250 static int open_disk(int flag);
251 static ssize_t read_disk(off_t sector, void *buf);
252 static int write_disk(off_t sector, void *buf);
253 static int get_params(void);
254 static int read_s0(void);
255 static int write_s0(void);
256 static int ok(const char *str);
257 static int decimal(const char *str, int *num, int deflt, uint32_t maxval);
258 static int read_config(char *config_file);
259 static void reset_boot(void);
260 static int sanitize_partition(struct dos_partition *);
261 static void usage(void);
262 
263 int
264 main(int argc, char *argv[])
265 {
266 	int	c, i;
267 	int	partition = -1;
268 	struct	dos_partition *partp;
269 
270 	while ((c = getopt(argc, argv, "BIab:f:ipqstuv1234")) != -1)
271 		switch (c) {
272 		case 'B':
273 			B_flag = 1;
274 			break;
275 		case 'I':
276 			I_flag = 1;
277 			break;
278 		case 'a':
279 			a_flag = 1;
280 			break;
281 		case 'b':
282 			b_flag = optarg;
283 			break;
284 		case 'f':
285 			f_flag = optarg;
286 			break;
287 		case 'i':
288 			i_flag = 1;
289 			break;
290 		case 'p':
291 			print_config_flag = 1;
292 			break;
293 		case 'q':
294 			q_flag = 1;
295 			break;
296 		case 's':
297 			s_flag = 1;
298 			break;
299 		case 't':
300 			t_flag = 1;
301 			break;
302 		case 'u':
303 			u_flag = 1;
304 			break;
305 		case 'v':
306 			v_flag = 1;
307 			break;
308 		case '1':
309 		case '2':
310 		case '3':
311 		case '4':
312 			partition = c - '0';
313 			break;
314 		default:
315 			usage();
316 		}
317 	if (f_flag || i_flag)
318 		u_flag = 1;
319 	if (t_flag)
320 		v_flag = 1;
321 	argc -= optind;
322 	argv += optind;
323 
324 	if (argc == 0) {
325 		disk = get_rootdisk();
326 	} else {
327 		disk = g_device_path(argv[0]);
328 		if (disk == NULL)
329 			err(1, "unable to get correct path for %s", argv[0]);
330 	}
331 	if (open_disk(u_flag) < 0)
332 		err(1, "cannot open disk %s", disk);
333 
334 	/* (abu)use mboot.bootinst to probe for the sector size */
335 	if ((mboot.bootinst = malloc(MAX_SEC_SIZE)) == NULL)
336 		err(1, "cannot allocate buffer to determine disk sector size");
337 	if (read_disk(0, mboot.bootinst) == -1)
338 		errx(1, "could not detect sector size");
339 	free(mboot.bootinst);
340 	mboot.bootinst = NULL;
341 
342 	if (print_config_flag) {
343 		if (read_s0())
344 			err(1, "read_s0");
345 
346 		printf("# %s\n", disk);
347 		printf("g c%d h%d s%d\n", dos_cyls, dos_heads, dos_sectors);
348 
349 		for (i = 0; i < NDOSPART; i++) {
350 			partp = &mboot.parts[i];
351 
352 			if (partp->dp_start == 0 && partp->dp_size == 0)
353 				continue;
354 
355 			printf("p %d 0x%02x %lu %lu\n", i + 1, partp->dp_typ,
356 			    (u_long)partp->dp_start, (u_long)partp->dp_size);
357 
358 			/* Fill flags for the partition. */
359 			if (partp->dp_flag & 0x80)
360 				printf("a %d\n", i + 1);
361 		}
362 		exit(0);
363 	}
364 	if (s_flag) {
365 		if (read_s0())
366 			err(1, "read_s0");
367 		printf("%s: %d cyl %d hd %d sec\n", disk, dos_cyls, dos_heads,
368 		    dos_sectors);
369 		printf("Part  %11s %11s Type Flags\n", "Start", "Size");
370 		for (i = 0; i < NDOSPART; i++) {
371 			partp = &mboot.parts[i];
372 			if (partp->dp_start == 0 && partp->dp_size == 0)
373 				continue;
374 			printf("%4d: %11lu %11lu 0x%02x 0x%02x\n", i + 1,
375 			    (u_long) partp->dp_start,
376 			    (u_long) partp->dp_size, partp->dp_typ,
377 			    partp->dp_flag);
378 		}
379 		exit(0);
380 	}
381 
382 	printf("******* Working on device %s *******\n",disk);
383 
384 	if (I_flag) {
385 		read_s0();
386 		reset_boot();
387 		partp = &mboot.parts[0];
388 		partp->dp_typ = DOSPTYP_386BSD;
389 		partp->dp_flag = ACTIVE;
390 		partp->dp_start = dos_sectors;
391 		partp->dp_size = rounddown(disksecs, dos_cylsecs) -
392 		    dos_sectors;
393 		dos(partp);
394 		if (v_flag)
395 			print_s0();
396 		if (!t_flag)
397 			write_s0();
398 		exit(0);
399 	}
400 	if (f_flag) {
401 	    if (read_s0() || i_flag)
402 		reset_boot();
403 	    if (!read_config(f_flag))
404 		exit(1);
405 	    if (v_flag)
406 		print_s0();
407 	    if (!t_flag)
408 		write_s0();
409 	} else {
410 	    if(u_flag)
411 		get_params_to_use();
412 	    else
413 		print_params();
414 
415 	    if (read_s0())
416 		init_sector0(dos_sectors);
417 
418 	    printf("Media sector size is %d\n", secsize);
419 	    printf("Warning: BIOS sector numbering starts with sector 1\n");
420 	    printf("Information from DOS bootblock is:\n");
421 	    if (partition == -1)
422 		for (i = 1; i <= NDOSPART; i++)
423 		    change_part(i);
424 	    else
425 		change_part(partition);
426 
427 	    if (u_flag || a_flag)
428 		change_active(partition);
429 
430 	    if (B_flag)
431 		change_code();
432 
433 	    if (u_flag || a_flag || B_flag) {
434 		if (!t_flag) {
435 		    printf("\nWe haven't changed the partition table yet.  ");
436 		    printf("This is your last chance.\n");
437 		}
438 		print_s0();
439 		if (!t_flag) {
440 		    if (ok("Should we write new partition table?"))
441 			write_s0();
442 		} else {
443 		    printf("\n-t flag specified -- partition table not written.\n");
444 		}
445 	    }
446 	}
447 
448 	exit(0);
449 }
450 
451 static void
452 usage(void)
453 {
454 	fprintf(stderr, "%s%s",
455 		"usage: fdisk [-BIaipqstu] [-b bootcode] [-1234] [disk]\n",
456  		"       fdisk -f configfile [-itv] [disk]\n");
457         exit(1);
458 }
459 
460 static void
461 print_s0(void)
462 {
463 	int	i;
464 
465 	print_params();
466 	printf("Information from DOS bootblock is:\n");
467 	for (i = 1; i <= NDOSPART; i++) {
468 		printf("%d: ", i);
469 		print_part(&mboot.parts[i - 1]);
470 	}
471 }
472 
473 static struct dos_partition mtpart;
474 
475 static void
476 print_part(const struct dos_partition *partp)
477 {
478 	u_int64_t part_mb;
479 
480 	if (!bcmp(partp, &mtpart, sizeof (struct dos_partition))) {
481 		printf("<UNUSED>\n");
482 		return;
483 	}
484 	/*
485 	 * Be careful not to overflow.
486 	 */
487 	part_mb = partp->dp_size;
488 	part_mb *= secsize;
489 	part_mb /= (1024 * 1024);
490 	printf("sysid %d (%#04x),(%s)\n", partp->dp_typ, partp->dp_typ,
491 	    get_type(partp->dp_typ));
492 	printf("    start %lu, size %lu (%ju Meg), flag %x%s\n",
493 		(u_long)partp->dp_start,
494 		(u_long)partp->dp_size,
495 		(uintmax_t)part_mb,
496 		partp->dp_flag,
497 		partp->dp_flag == ACTIVE ? " (active)" : "");
498 	printf("\tbeg: cyl %d/ head %d/ sector %d;\n\tend: cyl %d/ head %d/ sector %d\n"
499 		,DPCYL(partp->dp_scyl, partp->dp_ssect)
500 		,partp->dp_shd
501 		,DPSECT(partp->dp_ssect)
502 		,DPCYL(partp->dp_ecyl, partp->dp_esect)
503 		,partp->dp_ehd
504 		,DPSECT(partp->dp_esect));
505 }
506 
507 
508 static void
509 init_boot(void)
510 {
511 	const char *fname;
512 	int fdesc, n;
513 	struct stat sb;
514 
515 	fname = b_flag ? b_flag : "/boot/mbr";
516 	if ((fdesc = open(fname, O_RDONLY)) == -1 ||
517 	    fstat(fdesc, &sb) == -1)
518 		err(1, "%s", fname);
519 	if (sb.st_size == 0)
520 		errx(1, "%s is empty, must not be.", fname);
521 	if ((mboot.bootinst_size = sb.st_size) % secsize != 0)
522 		errx(1, "%s: length must be a multiple of sector size", fname);
523 	if (mboot.bootinst != NULL)
524 		free(mboot.bootinst);
525 	if ((mboot.bootinst = malloc(mboot.bootinst_size = sb.st_size)) == NULL)
526 		errx(1, "%s: unable to allocate read buffer", fname);
527 	if ((n = read(fdesc, mboot.bootinst, mboot.bootinst_size)) == -1 ||
528 	    close(fdesc))
529 		err(1, "%s", fname);
530 	if (n != mboot.bootinst_size)
531 		errx(1, "%s: short read", fname);
532 }
533 
534 
535 static void
536 init_sector0(unsigned long start)
537 {
538 	struct dos_partition *partp = &mboot.parts[0];
539 
540 	init_boot();
541 
542 	partp->dp_typ = DOSPTYP_386BSD;
543 	partp->dp_flag = ACTIVE;
544 	start = roundup(start, dos_sectors);
545 	if(start == 0)
546 		start = dos_sectors;
547 	partp->dp_start = start;
548 	partp->dp_size = rounddown(disksecs, dos_cylsecs) - start;
549 
550 	dos(partp);
551 }
552 
553 static void
554 change_part(int i)
555 {
556     struct dos_partition *partp = &mboot.parts[i - 1];
557 
558     printf("The data for partition %d is:\n", i);
559     print_part(partp);
560 
561     if (u_flag && ok("Do you want to change it?")) {
562 	int tmp;
563 
564 	if (i_flag) {
565 	    bzero(partp, sizeof (*partp));
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(partp);
570 	    }
571 	}
572 
573 	do {
574 		Decimal("sysid (165=FreeBSD)", partp->dp_typ, tmp, 255);
575 		Decimal("start", partp->dp_start, tmp, NO_DISK_SECTORS);
576 		Decimal("size", partp->dp_size, tmp, NO_DISK_SECTORS);
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, NO_TRACK_CYLINDERS);
589 			Decimal("beginning head", thd, tmp, NO_TRACK_HEADS);
590 			Decimal("beginning sector", tsec, tmp, NO_TRACK_SECTORS);
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, NO_TRACK_CYLINDERS);
599 			Decimal("ending head", thd, tmp, NO_TRACK_HEADS);
600 			Decimal("ending sector", tsec, tmp, NO_TRACK_SECTORS);
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(partp);
608 	} while (!ok("Are we happy with this entry?"));
609     }
610 }
611 
612 static void
613 print_params(void)
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, 0);
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(void)
665 {
666 	if (ok("Do you want to change the boot code?"))
667 		init_boot();
668 }
669 
670 void
671 get_params_to_use(void)
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, 0);
680 			Decimal("BIOS's idea of #heads", dos_heads, tmp, 0);
681 			Decimal("BIOS's idea of #sectors", dos_sectors, tmp, 0);
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 	int rwmode;
724 
725 	/* Write mode if one of these flags are set. */
726 	rwmode = (a_flag || I_flag || B_flag || flag);
727 	fd = g_open(disk, rwmode);
728 	/* If the mode fails, try read-only if we didn't. */
729 	if (fd == -1 && errno == EPERM && rwmode)
730 		fd = g_open(disk, 0);
731 	if (fd == -1 && errno == ENXIO)
732 		return -2;
733 	if (fd == -1) {
734 		warnx("can't open device %s", disk);
735 		return -1;
736 	}
737 	if (get_params() == -1) {
738 		warnx("can't get disk parameters on %s", disk);
739 		return -1;
740 	}
741 	return fd;
742 }
743 
744 static ssize_t
745 read_disk(off_t sector, void *buf)
746 {
747 
748 	lseek(fd, (sector * 512), 0);
749 	if (secsize == 0)
750 		for (secsize = MIN_SEC_SIZE; secsize <= MAX_SEC_SIZE;
751 		     secsize *= 2) {
752 			/* try the read */
753 			int size = read(fd, buf, secsize);
754 			if (size == secsize)
755 				/* it worked so return */
756 				return secsize;
757 		}
758 	else
759 		return read(fd, buf, secsize);
760 
761 	/* we failed to read at any of the sizes */
762 	return -1;
763 }
764 
765 static int
766 geom_class_available(const char *name)
767 {
768 	struct gclass *class;
769 	struct gmesh mesh;
770 	int error;
771 
772 	error = geom_gettree(&mesh);
773 	if (error != 0)
774 		errc(1, error, "Cannot get GEOM tree");
775 
776 	LIST_FOREACH(class, &mesh.lg_class, lg_class) {
777 		if (strcmp(class->lg_name, name) == 0) {
778 			geom_deletetree(&mesh);
779 			return (1);
780 		}
781 	}
782 
783 	geom_deletetree(&mesh);
784 
785 	return (0);
786 }
787 
788 static int
789 write_disk(off_t sector, void *buf)
790 {
791 	ssize_t wr;
792 
793 	/*
794 	 * Try to write MBR directly. This may help when disk
795 	 * is not in use.
796 	 * XXX: hardcoded sectorsize
797 	 */
798 	wr = pwrite(fd, buf, secsize, (sector * 512));
799 	if (wr == secsize)
800 		return (0);
801 
802 	if (geom_class_available("PART") != 0)
803 		warnx("Failed to write MBR. Try to use gpart(8).");
804 	else
805 		warnx("Failed to write sector zero");
806 	return(EINVAL);
807 }
808 
809 static int
810 get_params(void)
811 {
812 	int error;
813 	u_int u;
814 	off_t o;
815 
816 	error = ioctl(fd, DIOCGFWSECTORS, &u);
817 	if (error == 0)
818 		sectors = dos_sectors = u;
819 	else
820 		sectors = dos_sectors = 63;
821 
822 	error = ioctl(fd, DIOCGFWHEADS, &u);
823 	if (error == 0)
824 		heads = dos_heads = u;
825 	else
826 		heads = dos_heads = 255;
827 
828 	dos_cylsecs = cylsecs = heads * sectors;
829 	disksecs = cyls * heads * sectors;
830 
831 	u = g_sectorsize(fd);
832 	if (u <= 0)
833 		return (-1);
834 
835 	o = g_mediasize(fd);
836 	if (o < 0)
837 		return (-1);
838 	if (o / u <= NO_DISK_SECTORS)
839 		disksecs = o / u;
840 	else
841 		disksecs = NO_DISK_SECTORS;
842 	cyls = dos_cyls = o / (u * dos_heads * dos_sectors);
843 
844 	return (0);
845 }
846 
847 static int
848 read_s0(void)
849 {
850 	int i;
851 
852 	mboot.bootinst_size = secsize;
853 	if (mboot.bootinst != NULL)
854 		free(mboot.bootinst);
855 	if ((mboot.bootinst = malloc(mboot.bootinst_size)) == NULL) {
856 		warnx("unable to allocate buffer to read fdisk "
857 		      "partition table");
858 		return -1;
859 	}
860 	if (read_disk(0, mboot.bootinst) == -1) {
861 		warnx("can't read fdisk partition table");
862 		return -1;
863 	}
864 	if (le16dec(&mboot.bootinst[DOSMAGICOFFSET]) != DOSMAGIC) {
865 		warnx("invalid fdisk partition table found");
866 		/* So should we initialize things */
867 		return -1;
868 	}
869 	for (i = 0; i < NDOSPART; i++)
870 		dos_partition_dec(
871 		    &mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
872 		    &mboot.parts[i]);
873 	return 0;
874 }
875 
876 static int
877 write_s0(void)
878 {
879 	int	sector, i;
880 
881 	if (iotest) {
882 		print_s0();
883 		return 0;
884 	}
885 	for(i = 0; i < NDOSPART; i++)
886 		dos_partition_enc(&mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
887 		    &mboot.parts[i]);
888 	le16enc(&mboot.bootinst[DOSMAGICOFFSET], DOSMAGIC);
889 	for(sector = 0; sector < mboot.bootinst_size / secsize; sector++)
890 		if (write_disk(sector,
891 			       &mboot.bootinst[sector * secsize]) == -1) {
892 			warn("can't write fdisk partition table");
893 			return -1;
894 		}
895 	return(0);
896 }
897 
898 
899 static int
900 ok(const char *str)
901 {
902 	printf("%s [n] ", str);
903 	fflush(stdout);
904 	if (fgets(lbuf, LBUF, stdin) == NULL)
905 		exit(1);
906 	lbuf[strlen(lbuf)-1] = 0;
907 
908 	if (*lbuf &&
909 		(!strcmp(lbuf, "yes") || !strcmp(lbuf, "YES") ||
910 		 !strcmp(lbuf, "y") || !strcmp(lbuf, "Y")))
911 		return 1;
912 	else
913 		return 0;
914 }
915 
916 static int
917 decimal(const char *str, int *num, int deflt, uint32_t maxval)
918 {
919 	long long acc;
920 	int c;
921 	char *cp;
922 
923 	while (1) {
924 		acc = 0;
925 		printf("Supply a decimal value for \"%s\" [%d] ", str, deflt);
926 		fflush(stdout);
927 		if (fgets(lbuf, LBUF, stdin) == NULL)
928 			exit(1);
929 		lbuf[strlen(lbuf)-1] = 0;
930 
931 		if (!*lbuf)
932 			return 0;
933 
934 		cp = lbuf;
935 		while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
936 		if (!c)
937 			return 0;
938 		while ((c = *cp++)) {
939 			if (c <= '9' && c >= '0') {
940 				if (acc <= maxval || maxval == 0)
941 					acc = acc * 10 + c - '0';
942 			} else
943 				break;
944 		}
945 		if (c == ' ' || c == '\t')
946 			while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
947 		if (!c) {
948 			if (maxval > 0 && acc > maxval) {
949 				acc = maxval;
950 				printf("%s exceeds maximum value allowed for "
951 				  "this field. The value has been reduced "
952 				  "to %lld\n", lbuf, acc);
953 			}
954 			*num = acc;
955 			return 1;
956 		} else
957 			printf("%s is an invalid decimal number.  Try again.\n",
958 				lbuf);
959 	}
960 }
961 
962 
963 static void
964 parse_config_line(char *line, CMD *command)
965 {
966     char	*cp, *end;
967 
968     cp = line;
969     while (1) {
970 	memset(command, 0, sizeof(*command));
971 
972 	while (isspace(*cp)) ++cp;
973 	if (*cp == '\0' || *cp == '#')
974 	    break;
975 	command->cmd = *cp++;
976 
977 	/*
978 	 * Parse args
979 	 */
980 	    while (1) {
981 	    while (isspace(*cp)) ++cp;
982 	    if (*cp == '\0')
983 		break;		/* eol */
984 	    if (*cp == '#')
985 		break;		/* found comment */
986 	    if (isalpha(*cp))
987 		command->args[command->n_args].argtype = *cp++;
988 	    end = NULL;
989 	    command->args[command->n_args].arg_val = strtoul(cp, &end, 0);
990  	    if (cp == end || (!isspace(*end) && *end != '\0')) {
991  		char ch;
992  		end = cp;
993  		while (!isspace(*end) && *end != '\0') ++end;
994  		ch = *end; *end = '\0';
995  		command->args[command->n_args].arg_str = strdup(cp);
996  		*end = ch;
997  	    } else
998  		command->args[command->n_args].arg_str = NULL;
999 	    cp = end;
1000 	    command->n_args++;
1001 	}
1002 	break;
1003     }
1004 }
1005 
1006 
1007 static int
1008 process_geometry(CMD *command)
1009 {
1010     int		status = 1, i;
1011 
1012     while (1) {
1013 	geom_processed = 1;
1014 	    if (part_processed) {
1015 	    warnx(
1016 	"ERROR line %d: the geometry specification line must occur before\n\
1017     all partition specifications",
1018 		    current_line_number);
1019 	    status = 0;
1020 	    break;
1021 	}
1022 	    if (command->n_args != 3) {
1023 	    warnx("ERROR line %d: incorrect number of geometry args",
1024 		    current_line_number);
1025 	    status = 0;
1026 	    break;
1027 	}
1028 	    dos_cyls = 0;
1029 	    dos_heads = 0;
1030 	    dos_sectors = 0;
1031 	    for (i = 0; i < 3; ++i) {
1032 		    switch (command->args[i].argtype) {
1033 	    case 'c':
1034 		dos_cyls = command->args[i].arg_val;
1035 		break;
1036 	    case 'h':
1037 		dos_heads = command->args[i].arg_val;
1038 		break;
1039 	    case 's':
1040 		dos_sectors = command->args[i].arg_val;
1041 		break;
1042 	    default:
1043 		warnx(
1044 		"ERROR line %d: unknown geometry arg type: '%c' (0x%02x)",
1045 			current_line_number, command->args[i].argtype,
1046 			command->args[i].argtype);
1047 		status = 0;
1048 		break;
1049 	    }
1050 	}
1051 	if (status == 0)
1052 	    break;
1053 
1054 	dos_cylsecs = dos_heads * dos_sectors;
1055 
1056 	/*
1057 	 * Do sanity checks on parameter values
1058 	 */
1059 	    if (dos_cyls == 0) {
1060 	    warnx("ERROR line %d: number of cylinders not specified",
1061 		    current_line_number);
1062 	    status = 0;
1063 	}
1064 	    if (dos_cyls > 1024) {
1065 	    warnx(
1066 	"WARNING line %d: number of cylinders (%d) may be out-of-range\n\
1067     (must be within 1-1024 for normal BIOS operation, unless the entire disk\n\
1068     is dedicated to FreeBSD)",
1069 		    current_line_number, dos_cyls);
1070 	}
1071 
1072 	    if (dos_heads == 0) {
1073 	    warnx("ERROR line %d: number of heads not specified",
1074 		    current_line_number);
1075 	    status = 0;
1076 	    } else if (dos_heads > 256) {
1077 	    warnx("ERROR line %d: number of heads must be within (1-256)",
1078 		    current_line_number);
1079 	    status = 0;
1080 	}
1081 
1082 	    if (dos_sectors == 0) {
1083 	    warnx("ERROR line %d: number of sectors not specified",
1084 		    current_line_number);
1085 	    status = 0;
1086 	    } else if (dos_sectors > 63) {
1087 	    warnx("ERROR line %d: number of sectors must be within (1-63)",
1088 		    current_line_number);
1089 	    status = 0;
1090 	}
1091 
1092 	break;
1093     }
1094     return (status);
1095 }
1096 
1097 static u_int32_t
1098 str2sectors(const char *str)
1099 {
1100 	char *end;
1101 	unsigned long val;
1102 
1103 	val = strtoul(str, &end, 0);
1104 	if (str == end || *end == '\0') {
1105 		warnx("ERROR line %d: unexpected size: \'%s\'",
1106 		    current_line_number, str);
1107 		return NO_DISK_SECTORS;
1108 	}
1109 
1110 	if (*end == 'K')
1111 		val *= 1024UL / secsize;
1112 	else if (*end == 'M')
1113 		val *= 1024UL * 1024UL / secsize;
1114 	else if (*end == 'G')
1115 		val *= 1024UL * 1024UL * 1024UL / secsize;
1116 	else {
1117 		warnx("ERROR line %d: unexpected modifier: %c "
1118 		    "(not K/M/G)", current_line_number, *end);
1119 		return NO_DISK_SECTORS;
1120 	}
1121 
1122 	return val;
1123 }
1124 
1125 static int
1126 process_partition(CMD *command)
1127 {
1128     int				status = 0, partition;
1129     u_int32_t			prev_head_boundary, prev_cyl_boundary;
1130     u_int32_t			adj_size, max_end;
1131     struct dos_partition	*partp;
1132 
1133 	while (1) {
1134 	part_processed = 1;
1135 		if (command->n_args != 4) {
1136 	    warnx("ERROR line %d: incorrect number of partition args",
1137 		    current_line_number);
1138 	    break;
1139 	}
1140 	partition = command->args[0].arg_val;
1141 		if (partition < 1 || partition > 4) {
1142 	    warnx("ERROR line %d: invalid partition number %d",
1143 		    current_line_number, partition);
1144 	    break;
1145 	}
1146 	partp = &mboot.parts[partition - 1];
1147 	bzero(partp, sizeof (*partp));
1148 	partp->dp_typ = command->args[1].arg_val;
1149 	if (command->args[2].arg_str != NULL) {
1150 		if (strcmp(command->args[2].arg_str, "*") == 0) {
1151 			int i;
1152 			partp->dp_start = dos_sectors;
1153 			for (i = 1; i < partition; i++) {
1154     				struct dos_partition *prev_partp;
1155 				prev_partp = ((struct dos_partition *)
1156 				    &mboot.parts) + i - 1;
1157 				if (prev_partp->dp_typ != 0)
1158 					partp->dp_start = prev_partp->dp_start +
1159 					    prev_partp->dp_size;
1160 			}
1161 			if (partp->dp_start % dos_sectors != 0) {
1162 				prev_head_boundary = rounddown(partp->dp_start,
1163 				    dos_sectors);
1164 		    		partp->dp_start = prev_head_boundary +
1165 				    dos_sectors;
1166 			}
1167 		} else {
1168 			partp->dp_start = str2sectors(command->args[2].arg_str);
1169 			if (partp->dp_start == NO_DISK_SECTORS)
1170 				break;
1171 		}
1172 	} else
1173 		partp->dp_start = command->args[2].arg_val;
1174 
1175 	if (command->args[3].arg_str != NULL) {
1176 		if (strcmp(command->args[3].arg_str, "*") == 0)
1177 			partp->dp_size = rounddown(disksecs, dos_cylsecs) -
1178 			    partp->dp_start;
1179 		else {
1180 			partp->dp_size = str2sectors(command->args[3].arg_str);
1181 			if (partp->dp_size == NO_DISK_SECTORS)
1182 				break;
1183 		}
1184 		prev_cyl_boundary = rounddown(partp->dp_start + partp->dp_size,
1185 		    dos_cylsecs);
1186 		if (prev_cyl_boundary > partp->dp_start)
1187 			partp->dp_size = prev_cyl_boundary - partp->dp_start;
1188 	} else
1189 		partp->dp_size = command->args[3].arg_val;
1190 
1191 	max_end = partp->dp_start + partp->dp_size;
1192 
1193 	if (partp->dp_typ == 0) {
1194 	    /*
1195 	     * Get out, the partition is marked as unused.
1196 	     */
1197 	    /*
1198 	     * Insure that it's unused.
1199 	     */
1200 	    bzero(partp, sizeof(*partp));
1201 	    status = 1;
1202 	    break;
1203 	}
1204 
1205 	/*
1206 	 * Adjust start upwards, if necessary, to fall on a head boundary.
1207 	 */
1208 		if (partp->dp_start % dos_sectors != 0) {
1209 	    prev_head_boundary = rounddown(partp->dp_start, dos_sectors);
1210 	    if (max_end < dos_sectors ||
1211 			    prev_head_boundary > max_end - dos_sectors) {
1212 		/*
1213 		 * Can't go past end of partition
1214 		 */
1215 		warnx(
1216 	"ERROR line %d: unable to adjust start of partition %d to fall on\n\
1217     a head boundary",
1218 			current_line_number, partition);
1219 		break;
1220 	    }
1221 	    warnx(
1222 	"WARNING: adjusting start offset of partition %d\n\
1223     from %u to %u, to fall on a head boundary",
1224 		    partition, (u_int)partp->dp_start,
1225 		    (u_int)(prev_head_boundary + dos_sectors));
1226 	    partp->dp_start = prev_head_boundary + dos_sectors;
1227 	}
1228 
1229 	/*
1230 	 * Adjust size downwards, if necessary, to fall on a cylinder
1231 	 * boundary.
1232 	 */
1233 	prev_cyl_boundary = rounddown(partp->dp_start + partp->dp_size,
1234 	    dos_cylsecs);
1235 	if (prev_cyl_boundary > partp->dp_start)
1236 	    adj_size = prev_cyl_boundary - partp->dp_start;
1237 		else {
1238 	    warnx(
1239 	"ERROR: could not adjust partition to start on a head boundary\n\
1240     and end on a cylinder boundary.");
1241 	    return (0);
1242 	}
1243 		if (adj_size != partp->dp_size) {
1244 	    warnx(
1245 	"WARNING: adjusting size of partition %d from %u to %u\n\
1246     to end on a cylinder boundary",
1247 		    partition, (u_int)partp->dp_size, (u_int)adj_size);
1248 	    partp->dp_size = adj_size;
1249 	}
1250 		if (partp->dp_size == 0) {
1251 	    warnx("ERROR line %d: size of partition %d is zero",
1252 		    current_line_number, partition);
1253 	    break;
1254 	}
1255 
1256 	dos(partp);
1257 	status = 1;
1258 	break;
1259     }
1260     return (status);
1261 }
1262 
1263 
1264 static int
1265 process_active(CMD *command)
1266 {
1267     int				status = 0, partition, i;
1268     struct dos_partition	*partp;
1269 
1270 	while (1) {
1271 	active_processed = 1;
1272 		if (command->n_args != 1) {
1273 	    warnx("ERROR line %d: incorrect number of active args",
1274 		    current_line_number);
1275 	    status = 0;
1276 	    break;
1277 	}
1278 	partition = command->args[0].arg_val;
1279 		if (partition < 1 || partition > 4) {
1280 	    warnx("ERROR line %d: invalid partition number %d",
1281 		    current_line_number, partition);
1282 	    break;
1283 	}
1284 	/*
1285 	 * Reset active partition
1286 	 */
1287 	partp = mboot.parts;
1288 	for (i = 0; i < NDOSPART; i++)
1289 	    partp[i].dp_flag = 0;
1290 	partp[partition-1].dp_flag = ACTIVE;
1291 
1292 	status = 1;
1293 	break;
1294     }
1295     return (status);
1296 }
1297 
1298 
1299 static int
1300 process_line(char *line)
1301 {
1302     CMD		command;
1303     int		status = 1;
1304 
1305 	while (1) {
1306 	parse_config_line(line, &command);
1307 		switch (command.cmd) {
1308 	case 0:
1309 	    /*
1310 	     * Comment or blank line
1311 	     */
1312 	    break;
1313 	case 'g':
1314 	    /*
1315 	     * Set geometry
1316 	     */
1317 	    status = process_geometry(&command);
1318 	    break;
1319 	case 'p':
1320 	    status = process_partition(&command);
1321 	    break;
1322 	case 'a':
1323 	    status = process_active(&command);
1324 	    break;
1325 	default:
1326 	    status = 0;
1327 	    break;
1328 	}
1329 	break;
1330     }
1331     return (status);
1332 }
1333 
1334 
1335 static int
1336 read_config(char *config_file)
1337 {
1338     FILE	*fp = NULL;
1339     int		status = 1;
1340     char	buf[1010];
1341 
1342 	while (1) {
1343 		if (strcmp(config_file, "-") != 0) {
1344 	    /*
1345 	     * We're not reading from stdin
1346 	     */
1347 			if ((fp = fopen(config_file, "r")) == NULL) {
1348 		status = 0;
1349 		break;
1350 	    }
1351 		} else {
1352 	    fp = stdin;
1353 	}
1354 	current_line_number = 0;
1355 		while (!feof(fp)) {
1356 	    if (fgets(buf, sizeof(buf), fp) == NULL)
1357 		break;
1358 	    ++current_line_number;
1359 	    status = process_line(buf);
1360 	    if (status == 0)
1361 		break;
1362 	    }
1363 	break;
1364     }
1365 	if (fp) {
1366 	/*
1367 	 * It doesn't matter if we're reading from stdin, as we've reached EOF
1368 	 */
1369 	fclose(fp);
1370     }
1371     return (status);
1372 }
1373 
1374 
1375 static void
1376 reset_boot(void)
1377 {
1378     int				i;
1379     struct dos_partition	*partp;
1380 
1381     init_boot();
1382     for (i = 0; i < 4; ++i) {
1383 	partp = &mboot.parts[i];
1384 	bzero(partp, sizeof(*partp));
1385     }
1386 }
1387 
1388 static int
1389 sanitize_partition(struct dos_partition *partp)
1390 {
1391     u_int32_t			prev_head_boundary, prev_cyl_boundary;
1392     u_int32_t			max_end, size, start;
1393 
1394     start = partp->dp_start;
1395     size = partp->dp_size;
1396     max_end = start + size;
1397     /* Only allow a zero size if the partition is being marked unused. */
1398     if (size == 0) {
1399 	if (start == 0 && partp->dp_typ == 0)
1400 	    return (1);
1401 	warnx("ERROR: size of partition is zero");
1402 	return (0);
1403     }
1404     /* Return if no adjustment is necessary. */
1405     if (start % dos_sectors == 0 && (start + size) % dos_sectors == 0)
1406 	return (1);
1407 
1408     if (start == 0) {
1409 	    warnx("WARNING: partition overlaps with partition table");
1410 	    if (ok("Correct this automatically?"))
1411 		    start = dos_sectors;
1412     }
1413     if (start % dos_sectors != 0)
1414 	warnx("WARNING: partition does not start on a head boundary");
1415     if ((start  +size) % dos_sectors != 0)
1416 	warnx("WARNING: partition does not end on a cylinder boundary");
1417     warnx("WARNING: this may confuse the BIOS or some operating systems");
1418     if (!ok("Correct this automatically?"))
1419 	return (1);
1420 
1421     /*
1422      * Adjust start upwards, if necessary, to fall on a head boundary.
1423      */
1424     if (start % dos_sectors != 0) {
1425 	prev_head_boundary = rounddown(start, dos_sectors);
1426 	if (max_end < dos_sectors ||
1427 	    prev_head_boundary >= max_end - dos_sectors) {
1428 	    /*
1429 	     * Can't go past end of partition
1430 	     */
1431 	    warnx(
1432     "ERROR: unable to adjust start of partition to fall on a head boundary");
1433 	    return (0);
1434         }
1435 	start = prev_head_boundary + dos_sectors;
1436     }
1437 
1438     /*
1439      * Adjust size downwards, if necessary, to fall on a cylinder
1440      * boundary.
1441      */
1442     prev_cyl_boundary = rounddown(start + size, dos_cylsecs);
1443     if (prev_cyl_boundary > start)
1444 	size = prev_cyl_boundary - start;
1445     else {
1446 	warnx("ERROR: could not adjust partition to start on a head boundary\n\
1447     and end on a cylinder boundary.");
1448 	return (0);
1449     }
1450 
1451     /* Finally, commit any changes to partp and return. */
1452     if (start != partp->dp_start) {
1453 	warnx("WARNING: adjusting start offset of partition to %u",
1454 	    (u_int)start);
1455 	partp->dp_start = start;
1456     }
1457     if (size != partp->dp_size) {
1458 	warnx("WARNING: adjusting size of partition to %u", (u_int)size);
1459 	partp->dp_size = size;
1460     }
1461 
1462     return (1);
1463 }
1464 
1465 /*
1466  * Try figuring out the root device's canonical disk name.
1467  * The following choices are considered:
1468  *   /dev/ad0s1a     => /dev/ad0
1469  *   /dev/da0a       => /dev/da0
1470  *   /dev/vinum/root => /dev/vinum/root
1471  * A ".eli" part is removed if it exists (see geli(8)).
1472  * A ".journal" ending is removed if it exists (see gjournal(8)).
1473  */
1474 static char *
1475 get_rootdisk(void)
1476 {
1477 	struct statfs rootfs;
1478 	regex_t re;
1479 #define NMATCHES 2
1480 	regmatch_t rm[NMATCHES];
1481 	char dev[PATH_MAX], *s;
1482 	int rv;
1483 
1484 	if (statfs("/", &rootfs) == -1)
1485 		err(1, "statfs(\"/\")");
1486 
1487 	if ((rv = regcomp(&re, "^(/dev/[a-z/]+[0-9]*)([sp][0-9]+)?[a-h]?(\\.journal)?$",
1488 		    REG_EXTENDED)) != 0)
1489 		errx(1, "regcomp() failed (%d)", rv);
1490 	strlcpy(dev, rootfs.f_mntfromname, sizeof (dev));
1491 	if ((s = strstr(dev, ".eli")) != NULL)
1492 	    memmove(s, s+4, strlen(s + 4) + 1);
1493 
1494 	if ((rv = regexec(&re, dev, NMATCHES, rm, 0)) != 0)
1495 		errx(1,
1496 "mounted root fs resource doesn't match expectations (regexec returned %d)",
1497 		    rv);
1498 	if ((s = malloc(rm[1].rm_eo - rm[1].rm_so + 1)) == NULL)
1499 		errx(1, "out of memory");
1500 	memcpy(s, rootfs.f_mntfromname + rm[1].rm_so,
1501 	    rm[1].rm_eo - rm[1].rm_so);
1502 	s[rm[1].rm_eo - rm[1].rm_so] = 0;
1503 
1504 	return s;
1505 }
1506