xref: /freebsd/sbin/fdisk/fdisk.c (revision 884a2a699669ec61e2366e3e358342dbc94be24a)
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 NO_DISK_SECTORS ((u_int32_t)-1)
53 #define NO_TRACK_CYLINDERS 1023
54 #define NO_TRACK_HEADS 255
55 #define NO_TRACK_SECTORS 63
56 #define LBUF 100
57 static char lbuf[LBUF];
58 
59 /*
60  *
61  * Ported to 386bsd by Julian Elischer  Thu Oct 15 20:26:46 PDT 1992
62  *
63  * 14-Dec-89  Robert Baron (rvb) at Carnegie-Mellon University
64  *	Copyright (c) 1989	Robert. V. Baron
65  *	Created.
66  */
67 
68 #define Decimal(str, ans, tmp, maxval) if (decimal(str, &tmp, ans, maxval)) ans = tmp
69 
70 #define RoundCyl(x) ((((x) + cylsecs - 1) / cylsecs) * cylsecs)
71 
72 #define MAX_SEC_SIZE 2048	/* maximum section 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, disksecs;
79 
80 struct mboot {
81 	unsigned char *bootinst;  /* boot code */
82 	off_t bootinst_size;
83 	struct	dos_partition parts[NDOSPART];
84 };
85 
86 static struct mboot mboot;
87 static int fd;
88 
89 #define ACTIVE 0x80
90 
91 static uint dos_cyls;
92 static uint dos_heads;
93 static uint dos_sectors;
94 static uint dos_cylsecs;
95 
96 #define DOSSECT(s,c) ((s & 0x3f) | ((c >> 2) & 0xc0))
97 #define DOSCYL(c)	(c & 0xff)
98 
99 #define MAX_ARGS	10
100 
101 static int	current_line_number;
102 
103 static int	geom_processed = 0;
104 static int	part_processed = 0;
105 static int	active_processed = 0;
106 
107 typedef struct cmd {
108     char		cmd;
109     int			n_args;
110     struct arg {
111 	char	argtype;
112 	int	arg_val;
113 	char	*arg_str;
114     }			args[MAX_ARGS];
115 } CMD;
116 
117 static int B_flag  = 0;		/* replace boot code */
118 static int I_flag  = 0;		/* use entire disk for FreeBSD */
119 static int a_flag  = 0;		/* set active partition */
120 static char *b_flag = NULL;	/* path to boot code */
121 static int i_flag  = 0;		/* replace partition data */
122 static int q_flag  = 0;		/* Be quiet */
123 static int u_flag  = 0;		/* update partition data */
124 static int s_flag  = 0;		/* Print a summary and exit */
125 static int t_flag  = 0;		/* test only */
126 static char *f_flag = NULL;	/* Read config info from file */
127 static int v_flag  = 0;		/* Be verbose */
128 static int print_config_flag = 0;
129 
130 /*
131  * A list of partition types, probably outdated.
132  */
133 static const char *const part_types[256] = {
134 	[0x00] = "unused",
135 	[0x01] = "Primary DOS with 12 bit FAT",
136 	[0x02] = "XENIX / file system",
137 	[0x03] = "XENIX /usr file system",
138 	[0x04] = "Primary DOS with 16 bit FAT (< 32MB)",
139 	[0x05] = "Extended DOS",
140 	[0x06] = "Primary DOS, 16 bit FAT (>= 32MB)",
141 	[0x07] = "NTFS, OS/2 HPFS, QNX-2 (16 bit) or Advanced UNIX",
142 	[0x08] = "AIX file system or SplitDrive",
143 	[0x09] = "AIX boot partition or Coherent",
144 	[0x0A] = "OS/2 Boot Manager, OPUS or Coherent swap",
145 	[0x0B] = "DOS or Windows 95 with 32 bit FAT",
146 	[0x0C] = "DOS or Windows 95 with 32 bit FAT (LBA)",
147 	[0x0E] = "Primary 'big' DOS (>= 32MB, LBA)",
148 	[0x0F] = "Extended DOS (LBA)",
149 	[0x10] = "OPUS",
150 	[0x11] = "OS/2 BM: hidden DOS with 12-bit FAT",
151 	[0x12] = "Compaq diagnostics",
152 	[0x14] = "OS/2 BM: hidden DOS with 16-bit FAT (< 32MB)",
153 	[0x16] = "OS/2 BM: hidden DOS with 16-bit FAT (>= 32MB)",
154 	[0x17] = "OS/2 BM: hidden IFS (e.g. HPFS)",
155 	[0x18] = "AST Windows swapfile",
156 	[0x1b] = "ASUS Recovery partition (NTFS)",
157 	[0x24] = "NEC DOS",
158 	[0x3C] = "PartitionMagic recovery",
159 	[0x39] = "plan9",
160 	[0x40] = "VENIX 286",
161 	[0x41] = "Linux/MINIX (sharing disk with DRDOS)",
162 	[0x42] = "SFS or Linux swap (sharing disk with DRDOS)",
163 	[0x43] = "Linux native (sharing disk with DRDOS)",
164 	[0x4D] = "QNX 4.2 Primary",
165 	[0x4E] = "QNX 4.2 Secondary",
166 	[0x4F] = "QNX 4.2 Tertiary",
167 	[0x50] = "DM (disk manager)",
168 	[0x51] = "DM6 Aux1 (or Novell)",
169 	[0x52] = "CP/M or Microport SysV/AT",
170 	[0x53] = "DM6 Aux3",
171 	[0x54] = "DM6",
172 	[0x55] = "EZ-Drive (disk manager)",
173 	[0x56] = "Golden Bow (disk manager)",
174 	[0x5c] = "Priam Edisk (disk manager)", /* according to S. Widlake */
175 	[0x61] = "SpeedStor",
176 	[0x63] = "System V/386 (such as ISC UNIX), GNU HURD or Mach",
177 	[0x64] = "Novell Netware/286 2.xx",
178 	[0x65] = "Novell Netware/386 3.xx",
179 	[0x70] = "DiskSecure Multi-Boot",
180 	[0x75] = "PCIX",
181 	[0x77] = "QNX4.x",
182 	[0x78] = "QNX4.x 2nd part",
183 	[0x79] = "QNX4.x 3rd part",
184 	[0x80] = "Minix until 1.4a",
185 	[0x81] = "Minix since 1.4b, early Linux partition or Mitac disk manager",
186 	[0x82] = "Linux swap or Solaris x86",
187 	[0x83] = "Linux native",
188 	[0x84] = "OS/2 hidden C: drive",
189 	[0x85] = "Linux extended",
190 	[0x86] = "NTFS volume set??",
191 	[0x87] = "NTFS volume set??",
192 	[0x93] = "Amoeba file system",
193 	[0x94] = "Amoeba bad block table",
194 	[0x9F] = "BSD/OS",
195 	[0xA0] = "Suspend to Disk",
196 	[0xA5] = "FreeBSD/NetBSD/386BSD",
197 	[0xA6] = "OpenBSD",
198 	[0xA7] = "NeXTSTEP",
199 	[0xA9] = "NetBSD",
200 	[0xAC] = "IBM JFS",
201 	[0xAF] = "HFS+",
202 	[0xB7] = "BSDI BSD/386 file system",
203 	[0xB8] = "BSDI BSD/386 swap",
204 	[0xBE] = "Solaris x86 boot",
205 	[0xBF] = "Solaris x86 (new)",
206 	[0xC1] = "DRDOS/sec with 12-bit FAT",
207 	[0xC4] = "DRDOS/sec with 16-bit FAT (< 32MB)",
208 	[0xC6] = "DRDOS/sec with 16-bit FAT (>= 32MB)",
209 	[0xC7] = "Syrinx",
210 	[0xDB] = "CP/M, Concurrent CP/M, Concurrent DOS or CTOS",
211 	[0xDE] = "DELL Utilities - FAT filesystem",
212 	[0xE1] = "DOS access or SpeedStor with 12-bit FAT extended partition",
213 	[0xE3] = "DOS R/O or SpeedStor",
214 	[0xE4] = "SpeedStor with 16-bit FAT extended partition < 1024 cyl.",
215 	[0xEB] = "BeOS file system",
216 	[0xEE] = "EFI GPT",
217 	[0xEF] = "EFI System Partition",
218 	[0xF1] = "SpeedStor",
219 	[0xF2] = "DOS 3.3+ Secondary",
220 	[0xF4] = "SpeedStor large partition",
221 	[0xFE] = "SpeedStor >1024 cyl. or LANstep",
222 	[0xFF] = "Xenix bad blocks table",
223 };
224 
225 static const char *
226 get_type(int t)
227 {
228 	const char *ret;
229 
230 	ret = (t >= 0 && t <= 255) ? part_types[t] : NULL;
231 	return ret ? ret : "unknown";
232 }
233 
234 
235 static void print_s0(void);
236 static void print_part(const struct dos_partition *);
237 static void init_sector0(unsigned long start);
238 static void init_boot(void);
239 static void change_part(int i);
240 static void print_params(void);
241 static void change_active(int which);
242 static void change_code(void);
243 static void get_params_to_use(void);
244 static char *get_rootdisk(void);
245 static void dos(struct dos_partition *partp);
246 static int open_disk(int flag);
247 static ssize_t read_disk(off_t sector, void *buf);
248 static int write_disk(off_t sector, void *buf);
249 static int get_params(void);
250 static int read_s0(void);
251 static int write_s0(void);
252 static int ok(const char *str);
253 static int decimal(const char *str, int *num, int deflt, uint32_t maxval);
254 static int read_config(char *config_file);
255 static void reset_boot(void);
256 static int sanitize_partition(struct dos_partition *);
257 static void usage(void);
258 
259 int
260 main(int argc, char *argv[])
261 {
262 	int	c, i;
263 	int	partition = -1;
264 	struct	dos_partition *partp;
265 
266 	while ((c = getopt(argc, argv, "BIab:f:ipqstuv1234")) != -1)
267 		switch (c) {
268 		case 'B':
269 			B_flag = 1;
270 			break;
271 		case 'I':
272 			I_flag = 1;
273 			break;
274 		case 'a':
275 			a_flag = 1;
276 			break;
277 		case 'b':
278 			b_flag = optarg;
279 			break;
280 		case 'f':
281 			f_flag = optarg;
282 			break;
283 		case 'i':
284 			i_flag = 1;
285 			break;
286 		case 'p':
287 			print_config_flag = 1;
288 			break;
289 		case 'q':
290 			q_flag = 1;
291 			break;
292 		case 's':
293 			s_flag = 1;
294 			break;
295 		case 't':
296 			t_flag = 1;
297 			break;
298 		case 'u':
299 			u_flag = 1;
300 			break;
301 		case 'v':
302 			v_flag = 1;
303 			break;
304 		case '1':
305 		case '2':
306 		case '3':
307 		case '4':
308 			partition = c - '0';
309 			break;
310 		default:
311 			usage();
312 		}
313 	if (f_flag || i_flag)
314 		u_flag = 1;
315 	if (t_flag)
316 		v_flag = 1;
317 	argc -= optind;
318 	argv += optind;
319 
320 	if (argc == 0) {
321 		disk = get_rootdisk();
322 	} else {
323 		disk = g_device_path(argv[0]);
324 		if (disk == NULL)
325 			err(1, "unable to get correct path for %s", argv[0]);
326 	}
327 	if (open_disk(u_flag) < 0)
328 		err(1, "cannot open disk %s", disk);
329 
330 	/* (abu)use mboot.bootinst to probe for the sector size */
331 	if ((mboot.bootinst = malloc(MAX_SEC_SIZE)) == NULL)
332 		err(1, "cannot allocate buffer to determine disk sector size");
333 	if (read_disk(0, mboot.bootinst) == -1)
334 		errx(1, "could not detect sector size");
335 	free(mboot.bootinst);
336 	mboot.bootinst = NULL;
337 
338 	if (print_config_flag) {
339 		if (read_s0())
340 			err(1, "read_s0");
341 
342 		printf("# %s\n", disk);
343 		printf("g c%d h%d s%d\n", dos_cyls, dos_heads, dos_sectors);
344 
345 		for (i = 0; i < NDOSPART; i++) {
346 			partp = &mboot.parts[i];
347 
348 			if (partp->dp_start == 0 && partp->dp_size == 0)
349 				continue;
350 
351 			printf("p %d 0x%02x %lu %lu\n", i + 1, partp->dp_typ,
352 			    (u_long)partp->dp_start, (u_long)partp->dp_size);
353 
354 			/* Fill flags for the partition. */
355 			if (partp->dp_flag & 0x80)
356 				printf("a %d\n", i + 1);
357 		}
358 		exit(0);
359 	}
360 	if (s_flag) {
361 		if (read_s0())
362 			err(1, "read_s0");
363 		printf("%s: %d cyl %d hd %d sec\n", disk, dos_cyls, dos_heads,
364 		    dos_sectors);
365 		printf("Part  %11s %11s Type Flags\n", "Start", "Size");
366 		for (i = 0; i < NDOSPART; i++) {
367 			partp = &mboot.parts[i];
368 			if (partp->dp_start == 0 && partp->dp_size == 0)
369 				continue;
370 			printf("%4d: %11lu %11lu 0x%02x 0x%02x\n", i + 1,
371 			    (u_long) partp->dp_start,
372 			    (u_long) partp->dp_size, partp->dp_typ,
373 			    partp->dp_flag);
374 		}
375 		exit(0);
376 	}
377 
378 	printf("******* Working on device %s *******\n",disk);
379 
380 	if (I_flag) {
381 		read_s0();
382 		reset_boot();
383 		partp = &mboot.parts[0];
384 		partp->dp_typ = DOSPTYP_386BSD;
385 		partp->dp_flag = ACTIVE;
386 		partp->dp_start = dos_sectors;
387 		partp->dp_size = (disksecs / dos_cylsecs) * dos_cylsecs -
388 		    dos_sectors;
389 		dos(partp);
390 		if (v_flag)
391 			print_s0();
392 		if (!t_flag)
393 			write_s0();
394 		exit(0);
395 	}
396 	if (f_flag) {
397 	    if (read_s0() || i_flag)
398 		reset_boot();
399 	    if (!read_config(f_flag))
400 		exit(1);
401 	    if (v_flag)
402 		print_s0();
403 	    if (!t_flag)
404 		write_s0();
405 	} else {
406 	    if(u_flag)
407 		get_params_to_use();
408 	    else
409 		print_params();
410 
411 	    if (read_s0())
412 		init_sector0(dos_sectors);
413 
414 	    printf("Media sector size is %d\n", secsize);
415 	    printf("Warning: BIOS sector numbering starts with sector 1\n");
416 	    printf("Information from DOS bootblock is:\n");
417 	    if (partition == -1)
418 		for (i = 1; i <= NDOSPART; i++)
419 		    change_part(i);
420 	    else
421 		change_part(partition);
422 
423 	    if (u_flag || a_flag)
424 		change_active(partition);
425 
426 	    if (B_flag)
427 		change_code();
428 
429 	    if (u_flag || a_flag || B_flag) {
430 		if (!t_flag) {
431 		    printf("\nWe haven't changed the partition table yet.  ");
432 		    printf("This is your last chance.\n");
433 		}
434 		print_s0();
435 		if (!t_flag) {
436 		    if (ok("Should we write new partition table?"))
437 			write_s0();
438 		} else {
439 		    printf("\n-t flag specified -- partition table not written.\n");
440 		}
441 	    }
442 	}
443 
444 	exit(0);
445 }
446 
447 static void
448 usage()
449 {
450 	fprintf(stderr, "%s%s",
451 		"usage: fdisk [-BIaipqstu] [-b bootcode] [-1234] [disk]\n",
452  		"       fdisk -f configfile [-itv] [disk]\n");
453         exit(1);
454 }
455 
456 static void
457 print_s0(void)
458 {
459 	int	i;
460 
461 	print_params();
462 	printf("Information from DOS bootblock is:\n");
463 	for (i = 1; i <= NDOSPART; i++) {
464 		printf("%d: ", i);
465 		print_part(&mboot.parts[i - 1]);
466 	}
467 }
468 
469 static struct dos_partition mtpart;
470 
471 static void
472 print_part(const struct dos_partition *partp)
473 {
474 	u_int64_t part_mb;
475 
476 	if (!bcmp(partp, &mtpart, sizeof (struct dos_partition))) {
477 		printf("<UNUSED>\n");
478 		return;
479 	}
480 	/*
481 	 * Be careful not to overflow.
482 	 */
483 	part_mb = partp->dp_size;
484 	part_mb *= secsize;
485 	part_mb /= (1024 * 1024);
486 	printf("sysid %d (%#04x),(%s)\n", partp->dp_typ, partp->dp_typ,
487 	    get_type(partp->dp_typ));
488 	printf("    start %lu, size %lu (%ju Meg), flag %x%s\n",
489 		(u_long)partp->dp_start,
490 		(u_long)partp->dp_size,
491 		(uintmax_t)part_mb,
492 		partp->dp_flag,
493 		partp->dp_flag == ACTIVE ? " (active)" : "");
494 	printf("\tbeg: cyl %d/ head %d/ sector %d;\n\tend: cyl %d/ head %d/ sector %d\n"
495 		,DPCYL(partp->dp_scyl, partp->dp_ssect)
496 		,partp->dp_shd
497 		,DPSECT(partp->dp_ssect)
498 		,DPCYL(partp->dp_ecyl, partp->dp_esect)
499 		,partp->dp_ehd
500 		,DPSECT(partp->dp_esect));
501 }
502 
503 
504 static void
505 init_boot(void)
506 {
507 #ifndef __ia64__
508 	const char *fname;
509 	int fdesc, n;
510 	struct stat sb;
511 
512 	fname = b_flag ? b_flag : "/boot/mbr";
513 	if ((fdesc = open(fname, O_RDONLY)) == -1 ||
514 	    fstat(fdesc, &sb) == -1)
515 		err(1, "%s", fname);
516 	if ((mboot.bootinst_size = sb.st_size) % secsize != 0)
517 		errx(1, "%s: length must be a multiple of sector size", fname);
518 	if (mboot.bootinst != NULL)
519 		free(mboot.bootinst);
520 	if ((mboot.bootinst = malloc(mboot.bootinst_size = sb.st_size)) == NULL)
521 		errx(1, "%s: unable to allocate read buffer", fname);
522 	if ((n = read(fdesc, mboot.bootinst, mboot.bootinst_size)) == -1 ||
523 	    close(fdesc))
524 		err(1, "%s", fname);
525 	if (n != mboot.bootinst_size)
526 		errx(1, "%s: short read", fname);
527 #else
528 	if (mboot.bootinst != NULL)
529 		free(mboot.bootinst);
530 	mboot.bootinst_size = secsize;
531 	if ((mboot.bootinst = malloc(mboot.bootinst_size)) == NULL)
532 		errx(1, "unable to allocate boot block buffer");
533 	memset(mboot.bootinst, 0, mboot.bootinst_size);
534 	le16enc(&mboot.bootinst[DOSMAGICOFFSET], DOSMAGIC);
535 #endif
536 }
537 
538 
539 static void
540 init_sector0(unsigned long start)
541 {
542 	struct dos_partition *partp = &mboot.parts[0];
543 
544 	init_boot();
545 
546 	partp->dp_typ = DOSPTYP_386BSD;
547 	partp->dp_flag = ACTIVE;
548 	start = ((start + dos_sectors - 1) / dos_sectors) * dos_sectors;
549 	if(start == 0)
550 		start = dos_sectors;
551 	partp->dp_start = start;
552 	partp->dp_size = (disksecs / dos_cylsecs) * dos_cylsecs - start;
553 
554 	dos(partp);
555 }
556 
557 static void
558 change_part(int i)
559 {
560     struct dos_partition *partp = &mboot.parts[i - 1];
561 
562     printf("The data for partition %d is:\n", i);
563     print_part(partp);
564 
565     if (u_flag && ok("Do you want to change it?")) {
566 	int tmp;
567 
568 	if (i_flag) {
569 	    bzero(partp, sizeof (*partp));
570 	    if (i == 1) {
571 		init_sector0(1);
572 		printf("\nThe static data for the slice 1 has been reinitialized to:\n");
573 		print_part(partp);
574 	    }
575 	}
576 
577 	do {
578 		Decimal("sysid (165=FreeBSD)", partp->dp_typ, tmp, 255);
579 		Decimal("start", partp->dp_start, tmp, NO_DISK_SECTORS);
580 		Decimal("size", partp->dp_size, tmp, NO_DISK_SECTORS);
581 		if (!sanitize_partition(partp)) {
582 			warnx("ERROR: failed to adjust; setting sysid to 0");
583 			partp->dp_typ = 0;
584 		}
585 
586 		if (ok("Explicitly specify beg/end address ?"))
587 		{
588 			int	tsec,tcyl,thd;
589 			tcyl = DPCYL(partp->dp_scyl,partp->dp_ssect);
590 			thd = partp->dp_shd;
591 			tsec = DPSECT(partp->dp_ssect);
592 			Decimal("beginning cylinder", tcyl, tmp, NO_TRACK_CYLINDERS);
593 			Decimal("beginning head", thd, tmp, NO_TRACK_HEADS);
594 			Decimal("beginning sector", tsec, tmp, NO_TRACK_SECTORS);
595 			partp->dp_scyl = DOSCYL(tcyl);
596 			partp->dp_ssect = DOSSECT(tsec,tcyl);
597 			partp->dp_shd = thd;
598 
599 			tcyl = DPCYL(partp->dp_ecyl,partp->dp_esect);
600 			thd = partp->dp_ehd;
601 			tsec = DPSECT(partp->dp_esect);
602 			Decimal("ending cylinder", tcyl, tmp, NO_TRACK_CYLINDERS);
603 			Decimal("ending head", thd, tmp, NO_TRACK_HEADS);
604 			Decimal("ending sector", tsec, tmp, NO_TRACK_SECTORS);
605 			partp->dp_ecyl = DOSCYL(tcyl);
606 			partp->dp_esect = DOSSECT(tsec,tcyl);
607 			partp->dp_ehd = thd;
608 		} else
609 			dos(partp);
610 
611 		print_part(partp);
612 	} while (!ok("Are we happy with this entry?"));
613     }
614 }
615 
616 static void
617 print_params()
618 {
619 	printf("parameters extracted from in-core disklabel are:\n");
620 	printf("cylinders=%d heads=%d sectors/track=%d (%d blks/cyl)\n\n"
621 			,cyls,heads,sectors,cylsecs);
622 	if (dos_cyls > 1023 || dos_heads > 255 || dos_sectors > 63)
623 		printf("Figures below won't work with BIOS for partitions not in cyl 1\n");
624 	printf("parameters to be used for BIOS calculations are:\n");
625 	printf("cylinders=%d heads=%d sectors/track=%d (%d blks/cyl)\n\n"
626 		,dos_cyls,dos_heads,dos_sectors,dos_cylsecs);
627 }
628 
629 static void
630 change_active(int which)
631 {
632 	struct dos_partition *partp = &mboot.parts[0];
633 	int active, i, new, tmp;
634 
635 	active = -1;
636 	for (i = 0; i < NDOSPART; i++) {
637 		if ((partp[i].dp_flag & ACTIVE) == 0)
638 			continue;
639 		printf("Partition %d is marked active\n", i + 1);
640 		if (active == -1)
641 			active = i + 1;
642 	}
643 	if (a_flag && which != -1)
644 		active = which;
645 	else if (active == -1)
646 		active = 1;
647 
648 	if (!ok("Do you want to change the active partition?"))
649 		return;
650 setactive:
651 	do {
652 		new = active;
653 		Decimal("active partition", new, tmp, 0);
654 		if (new < 1 || new > 4) {
655 			printf("Active partition number must be in range 1-4."
656 					"  Try again.\n");
657 			goto setactive;
658 		}
659 		active = new;
660 	} while (!ok("Are you happy with this choice"));
661 	for (i = 0; i < NDOSPART; i++)
662 		partp[i].dp_flag = 0;
663 	if (active > 0 && active <= NDOSPART)
664 		partp[active-1].dp_flag = ACTIVE;
665 }
666 
667 static void
668 change_code()
669 {
670 	if (ok("Do you want to change the boot code?"))
671 		init_boot();
672 }
673 
674 void
675 get_params_to_use()
676 {
677 	int	tmp;
678 	print_params();
679 	if (ok("Do you want to change our idea of what BIOS thinks ?"))
680 	{
681 		do
682 		{
683 			Decimal("BIOS's idea of #cylinders", dos_cyls, tmp, 0);
684 			Decimal("BIOS's idea of #heads", dos_heads, tmp, 0);
685 			Decimal("BIOS's idea of #sectors", dos_sectors, tmp, 0);
686 			dos_cylsecs = dos_heads * dos_sectors;
687 			print_params();
688 		}
689 		while(!ok("Are you happy with this choice"));
690 	}
691 }
692 
693 
694 /***********************************************\
695 * Change real numbers into strange dos numbers	*
696 \***********************************************/
697 static void
698 dos(struct dos_partition *partp)
699 {
700 	int cy, sec;
701 	u_int32_t end;
702 
703 	if (partp->dp_typ == 0 && partp->dp_start == 0 && partp->dp_size == 0) {
704 		memcpy(partp, &mtpart, sizeof(*partp));
705 		return;
706 	}
707 
708 	/* Start c/h/s. */
709 	partp->dp_shd = partp->dp_start % dos_cylsecs / dos_sectors;
710 	cy = partp->dp_start / dos_cylsecs;
711 	sec = partp->dp_start % dos_sectors + 1;
712 	partp->dp_scyl = DOSCYL(cy);
713 	partp->dp_ssect = DOSSECT(sec, cy);
714 
715 	/* End c/h/s. */
716 	end = partp->dp_start + partp->dp_size - 1;
717 	partp->dp_ehd = end % dos_cylsecs / dos_sectors;
718 	cy = end / dos_cylsecs;
719 	sec = end % dos_sectors + 1;
720 	partp->dp_ecyl = DOSCYL(cy);
721 	partp->dp_esect = DOSSECT(sec, cy);
722 }
723 
724 static int
725 open_disk(int flag)
726 {
727 	int rwmode;
728 
729 	/* Write mode if one of these flags are set. */
730 	rwmode = (a_flag || I_flag || B_flag || flag);
731 	fd = g_open(disk, rwmode);
732 	/* If the mode fails, try read-only if we didn't. */
733 	if (fd == -1 && errno == EPERM && rwmode)
734 		fd = g_open(disk, 0);
735 	if (fd == -1 && errno == ENXIO)
736 		return -2;
737 	if (fd == -1) {
738 		warnx("can't open device %s", disk);
739 		return -1;
740 	}
741 	if (get_params() == -1) {
742 		warnx("can't get disk parameters on %s", disk);
743 		return -1;
744 	}
745 	return fd;
746 }
747 
748 static ssize_t
749 read_disk(off_t sector, void *buf)
750 {
751 
752 	lseek(fd, (sector * 512), 0);
753 	if (secsize == 0)
754 		for (secsize = MIN_SEC_SIZE; secsize <= MAX_SEC_SIZE;
755 		     secsize *= 2) {
756 			/* try the read */
757 			int size = read(fd, buf, secsize);
758 			if (size == secsize)
759 				/* it worked so return */
760 				return secsize;
761 		}
762 	else
763 		return read(fd, buf, secsize);
764 
765 	/* we failed to read at any of the sizes */
766 	return -1;
767 }
768 
769 static int
770 write_disk(off_t sector, void *buf)
771 {
772 	int error;
773 	struct gctl_req *grq;
774 	const char *errmsg;
775 	char fbuf[BUFSIZ], *pname;
776 	int i, fdw;
777 
778 	grq = gctl_get_handle();
779 	gctl_ro_param(grq, "verb", -1, "write MBR");
780 	gctl_ro_param(grq, "class", -1, "MBR");
781 	pname = g_providername(fd);
782 	if (pname == NULL) {
783 		warn("Error getting providername for %s", disk);
784 		return (-1);
785 	}
786 	gctl_ro_param(grq, "geom", -1, pname);
787 	gctl_ro_param(grq, "data", secsize, buf);
788 	errmsg = gctl_issue(grq);
789 	free(pname);
790 	if (errmsg == NULL) {
791 		gctl_free(grq);
792 		return(0);
793 	}
794 	if (!q_flag)	/* GEOM errors are benign, not all devices supported */
795 		warnx("%s", errmsg);
796 	gctl_free(grq);
797 
798 	error = pwrite(fd, buf, secsize, (sector * 512));
799 	if (error == secsize)
800 		return (0);
801 
802 	for (i = 1; i < 5; i++) {
803 		sprintf(fbuf, "%ss%d", disk, i);
804 		fdw = open(fbuf, O_RDWR, 0);
805 		if (fdw < 0)
806 			continue;
807 		error = ioctl(fdw, DIOCSMBR, buf);
808 		close(fdw);
809 		if (error == 0)
810 			return (0);
811 	}
812 	warnx("Failed to write sector zero");
813 	return(EINVAL);
814 }
815 
816 static int
817 get_params()
818 {
819 	int error;
820 	u_int u;
821 	off_t o;
822 
823 	error = ioctl(fd, DIOCGFWSECTORS, &u);
824 	if (error == 0)
825 		sectors = dos_sectors = u;
826 	else
827 		sectors = dos_sectors = 63;
828 
829 	error = ioctl(fd, DIOCGFWHEADS, &u);
830 	if (error == 0)
831 		heads = dos_heads = u;
832 	else
833 		heads = dos_heads = 255;
834 
835 	dos_cylsecs = cylsecs = heads * sectors;
836 	disksecs = cyls * heads * sectors;
837 
838 	u = g_sectorsize(fd);
839 	if (u <= 0)
840 		return (-1);
841 
842 	o = g_mediasize(fd);
843 	if (o < 0)
844 		return (-1);
845 	disksecs = o / u;
846 	cyls = dos_cyls = o / (u * dos_heads * dos_sectors);
847 
848 	return (disksecs);
849 }
850 
851 static int
852 read_s0()
853 {
854 	int i;
855 
856 	mboot.bootinst_size = secsize;
857 	if (mboot.bootinst != NULL)
858 		free(mboot.bootinst);
859 	if ((mboot.bootinst = malloc(mboot.bootinst_size)) == NULL) {
860 		warnx("unable to allocate buffer to read fdisk "
861 		      "partition table");
862 		return -1;
863 	}
864 	if (read_disk(0, mboot.bootinst) == -1) {
865 		warnx("can't read fdisk partition table");
866 		return -1;
867 	}
868 	if (le16dec(&mboot.bootinst[DOSMAGICOFFSET]) != DOSMAGIC) {
869 		warnx("invalid fdisk partition table found");
870 		/* So should we initialize things */
871 		return -1;
872 	}
873 	for (i = 0; i < NDOSPART; i++)
874 		dos_partition_dec(
875 		    &mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
876 		    &mboot.parts[i]);
877 	return 0;
878 }
879 
880 static int
881 write_s0()
882 {
883 	int	sector, i;
884 
885 	if (iotest) {
886 		print_s0();
887 		return 0;
888 	}
889 	for(i = 0; i < NDOSPART; i++)
890 		dos_partition_enc(&mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
891 		    &mboot.parts[i]);
892 	le16enc(&mboot.bootinst[DOSMAGICOFFSET], DOSMAGIC);
893 	for(sector = 0; sector < mboot.bootinst_size / secsize; sector++)
894 		if (write_disk(sector,
895 			       &mboot.bootinst[sector * secsize]) == -1) {
896 			warn("can't write fdisk partition table");
897 			return -1;
898 		}
899 	return(0);
900 }
901 
902 
903 static int
904 ok(const char *str)
905 {
906 	printf("%s [n] ", str);
907 	fflush(stdout);
908 	if (fgets(lbuf, LBUF, stdin) == NULL)
909 		exit(1);
910 	lbuf[strlen(lbuf)-1] = 0;
911 
912 	if (*lbuf &&
913 		(!strcmp(lbuf, "yes") || !strcmp(lbuf, "YES") ||
914 		 !strcmp(lbuf, "y") || !strcmp(lbuf, "Y")))
915 		return 1;
916 	else
917 		return 0;
918 }
919 
920 static int
921 decimal(const char *str, int *num, int deflt, uint32_t maxval)
922 {
923 	long long acc = 0;
924 	int c;
925 	char *cp;
926 
927 	while (1) {
928 		printf("Supply a decimal value for \"%s\" [%d] ", str, deflt);
929 		fflush(stdout);
930 		if (fgets(lbuf, LBUF, stdin) == NULL)
931 			exit(1);
932 		lbuf[strlen(lbuf)-1] = 0;
933 
934 		if (!*lbuf)
935 			return 0;
936 
937 		cp = lbuf;
938 		while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
939 		if (!c)
940 			return 0;
941 		while ((c = *cp++)) {
942 			if (c <= '9' && c >= '0') {
943 				if (maxval > 0 && acc <= maxval)
944 					acc = acc * 10 + c - '0';
945 			} else
946 				break;
947 		}
948 		if (c == ' ' || c == '\t')
949 			while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
950 		if (!c) {
951 			if (maxval > 0 && acc > maxval) {
952 				acc = maxval;
953 				printf("%s exceeds maximum value allowed for "
954 				  "this field. The value has been reduced "
955 				  "to %lld\n", lbuf, acc);
956 			}
957 			*num = acc;
958 			return 1;
959 		} else
960 			printf("%s is an invalid decimal number.  Try again.\n",
961 				lbuf);
962 	}
963 
964 }
965 
966 
967 static void
968 parse_config_line(char *line, CMD *command)
969 {
970     char	*cp, *end;
971 
972     cp = line;
973     while (1) {
974 	memset(command, 0, sizeof(*command));
975 
976 	while (isspace(*cp)) ++cp;
977 	if (*cp == '\0' || *cp == '#')
978 	    break;
979 	command->cmd = *cp++;
980 
981 	/*
982 	 * Parse args
983 	 */
984 	    while (1) {
985 	    while (isspace(*cp)) ++cp;
986 	    if (*cp == '\0')
987 		break;		/* eol */
988 	    if (*cp == '#')
989 		break;		/* found comment */
990 	    if (isalpha(*cp))
991 		command->args[command->n_args].argtype = *cp++;
992 	    end = NULL;
993 	    command->args[command->n_args].arg_val = strtol(cp, &end, 0);
994  	    if (cp == end || (!isspace(*end) && *end != '\0')) {
995  		char ch;
996  		end = cp;
997  		while (!isspace(*end) && *end != '\0') ++end;
998  		ch = *end; *end = '\0';
999  		command->args[command->n_args].arg_str = strdup(cp);
1000  		*end = ch;
1001  	    } else
1002  		command->args[command->n_args].arg_str = NULL;
1003 	    cp = end;
1004 	    command->n_args++;
1005 	}
1006 	break;
1007     }
1008 }
1009 
1010 
1011 static int
1012 process_geometry(CMD *command)
1013 {
1014     int		status = 1, i;
1015 
1016     while (1) {
1017 	geom_processed = 1;
1018 	    if (part_processed) {
1019 	    warnx(
1020 	"ERROR line %d: the geometry specification line must occur before\n\
1021     all partition specifications",
1022 		    current_line_number);
1023 	    status = 0;
1024 	    break;
1025 	}
1026 	    if (command->n_args != 3) {
1027 	    warnx("ERROR line %d: incorrect number of geometry args",
1028 		    current_line_number);
1029 	    status = 0;
1030 	    break;
1031 	}
1032 	    dos_cyls = 0;
1033 	    dos_heads = 0;
1034 	    dos_sectors = 0;
1035 	    for (i = 0; i < 3; ++i) {
1036 		    switch (command->args[i].argtype) {
1037 	    case 'c':
1038 		dos_cyls = command->args[i].arg_val;
1039 		break;
1040 	    case 'h':
1041 		dos_heads = command->args[i].arg_val;
1042 		break;
1043 	    case 's':
1044 		dos_sectors = command->args[i].arg_val;
1045 		break;
1046 	    default:
1047 		warnx(
1048 		"ERROR line %d: unknown geometry arg type: '%c' (0x%02x)",
1049 			current_line_number, command->args[i].argtype,
1050 			command->args[i].argtype);
1051 		status = 0;
1052 		break;
1053 	    }
1054 	}
1055 	if (status == 0)
1056 	    break;
1057 
1058 	dos_cylsecs = dos_heads * dos_sectors;
1059 
1060 	/*
1061 	 * Do sanity checks on parameter values
1062 	 */
1063 	    if (dos_cyls == 0) {
1064 	    warnx("ERROR line %d: number of cylinders not specified",
1065 		    current_line_number);
1066 	    status = 0;
1067 	}
1068 	    if (dos_cyls > 1024) {
1069 	    warnx(
1070 	"WARNING line %d: number of cylinders (%d) may be out-of-range\n\
1071     (must be within 1-1024 for normal BIOS operation, unless the entire disk\n\
1072     is dedicated to FreeBSD)",
1073 		    current_line_number, dos_cyls);
1074 	}
1075 
1076 	    if (dos_heads == 0) {
1077 	    warnx("ERROR line %d: number of heads not specified",
1078 		    current_line_number);
1079 	    status = 0;
1080 	    } else if (dos_heads > 256) {
1081 	    warnx("ERROR line %d: number of heads must be within (1-256)",
1082 		    current_line_number);
1083 	    status = 0;
1084 	}
1085 
1086 	    if (dos_sectors == 0) {
1087 	    warnx("ERROR line %d: number of sectors not specified",
1088 		    current_line_number);
1089 	    status = 0;
1090 	    } else if (dos_sectors > 63) {
1091 	    warnx("ERROR line %d: number of sectors must be within (1-63)",
1092 		    current_line_number);
1093 	    status = 0;
1094 	}
1095 
1096 	break;
1097     }
1098     return (status);
1099 }
1100 
1101 static u_int32_t
1102 str2sectors(const char *str)
1103 {
1104 	char *end;
1105 	unsigned long val;
1106 
1107 	val = strtoul(str, &end, 0);
1108 	if (str == end || *end == '\0') {
1109 		warnx("ERROR line %d: unexpected size: \'%s\'",
1110 		    current_line_number, str);
1111 		return NO_DISK_SECTORS;
1112 	}
1113 
1114 	if (*end == 'K')
1115 		val *= 1024UL / secsize;
1116 	else if (*end == 'M')
1117 		val *= 1024UL * 1024UL / secsize;
1118 	else if (*end == 'G')
1119 		val *= 1024UL * 1024UL * 1024UL / secsize;
1120 	else {
1121 		warnx("ERROR line %d: unexpected modifier: %c "
1122 		    "(not K/M/G)", current_line_number, *end);
1123 		return NO_DISK_SECTORS;
1124 	}
1125 
1126 	return val;
1127 }
1128 
1129 static int
1130 process_partition(CMD *command)
1131 {
1132     int				status = 0, partition;
1133     u_int32_t			prev_head_boundary, prev_cyl_boundary;
1134     u_int32_t			adj_size, max_end;
1135     struct dos_partition	*partp;
1136 
1137 	while (1) {
1138 	part_processed = 1;
1139 		if (command->n_args != 4) {
1140 	    warnx("ERROR line %d: incorrect number of partition args",
1141 		    current_line_number);
1142 	    break;
1143 	}
1144 	partition = command->args[0].arg_val;
1145 		if (partition < 1 || partition > 4) {
1146 	    warnx("ERROR line %d: invalid partition number %d",
1147 		    current_line_number, partition);
1148 	    break;
1149 	}
1150 	partp = &mboot.parts[partition - 1];
1151 	bzero(partp, sizeof (*partp));
1152 	partp->dp_typ = command->args[1].arg_val;
1153 	if (command->args[2].arg_str != NULL) {
1154 		if (strcmp(command->args[2].arg_str, "*") == 0) {
1155 			int i;
1156 			partp->dp_start = dos_sectors;
1157 			for (i = 1; i < partition; i++) {
1158     				struct dos_partition *prev_partp;
1159 				prev_partp = ((struct dos_partition *)
1160 				    &mboot.parts) + i - 1;
1161 				if (prev_partp->dp_typ != 0)
1162 					partp->dp_start = prev_partp->dp_start +
1163 					    prev_partp->dp_size;
1164 			}
1165 			if (partp->dp_start % dos_sectors != 0) {
1166 		    		prev_head_boundary = partp->dp_start /
1167 				    dos_sectors * dos_sectors;
1168 		    		partp->dp_start = prev_head_boundary +
1169 				    dos_sectors;
1170 			}
1171 		} else {
1172 			partp->dp_start = str2sectors(command->args[2].arg_str);
1173 			if (partp->dp_start == NO_DISK_SECTORS)
1174 				break;
1175 		}
1176 	} else
1177 		partp->dp_start = command->args[2].arg_val;
1178 
1179 	if (command->args[3].arg_str != NULL) {
1180 		if (strcmp(command->args[3].arg_str, "*") == 0)
1181 			partp->dp_size = ((disksecs / dos_cylsecs) *
1182 			    dos_cylsecs) - partp->dp_start;
1183 		else {
1184 			partp->dp_size = str2sectors(command->args[3].arg_str);
1185 			if (partp->dp_size == NO_DISK_SECTORS)
1186 				break;
1187 		}
1188 		prev_cyl_boundary = ((partp->dp_start + partp->dp_size) /
1189 		    dos_cylsecs) * dos_cylsecs;
1190 		if (prev_cyl_boundary > partp->dp_start)
1191 			partp->dp_size = prev_cyl_boundary - partp->dp_start;
1192 	} else
1193 		partp->dp_size = command->args[3].arg_val;
1194 
1195 	max_end = partp->dp_start + partp->dp_size;
1196 
1197 	if (partp->dp_typ == 0) {
1198 	    /*
1199 	     * Get out, the partition is marked as unused.
1200 	     */
1201 	    /*
1202 	     * Insure that it's unused.
1203 	     */
1204 	    bzero(partp, sizeof(*partp));
1205 	    status = 1;
1206 	    break;
1207 	}
1208 
1209 	/*
1210 	 * Adjust start upwards, if necessary, to fall on a head boundary.
1211 	 */
1212 		if (partp->dp_start % dos_sectors != 0) {
1213 	    prev_head_boundary = partp->dp_start / dos_sectors * dos_sectors;
1214 	    if (max_end < dos_sectors ||
1215 			    prev_head_boundary > max_end - dos_sectors) {
1216 		/*
1217 		 * Can't go past end of partition
1218 		 */
1219 		warnx(
1220 	"ERROR line %d: unable to adjust start of partition %d to fall on\n\
1221     a head boundary",
1222 			current_line_number, partition);
1223 		break;
1224 	    }
1225 	    warnx(
1226 	"WARNING: adjusting start offset of partition %d\n\
1227     from %u to %u, to fall on a head boundary",
1228 		    partition, (u_int)partp->dp_start,
1229 		    (u_int)(prev_head_boundary + dos_sectors));
1230 	    partp->dp_start = prev_head_boundary + dos_sectors;
1231 	}
1232 
1233 	/*
1234 	 * Adjust size downwards, if necessary, to fall on a cylinder
1235 	 * boundary.
1236 	 */
1237 	prev_cyl_boundary =
1238 	    ((partp->dp_start + partp->dp_size) / dos_cylsecs) * dos_cylsecs;
1239 	if (prev_cyl_boundary > partp->dp_start)
1240 	    adj_size = prev_cyl_boundary - partp->dp_start;
1241 		else {
1242 	    warnx(
1243 	"ERROR: could not adjust partition to start on a head boundary\n\
1244     and end on a cylinder boundary.");
1245 	    return (0);
1246 	}
1247 		if (adj_size != partp->dp_size) {
1248 	    warnx(
1249 	"WARNING: adjusting size of partition %d from %u to %u\n\
1250     to end on a cylinder boundary",
1251 		    partition, (u_int)partp->dp_size, (u_int)adj_size);
1252 	    partp->dp_size = adj_size;
1253 	}
1254 		if (partp->dp_size == 0) {
1255 	    warnx("ERROR line %d: size of partition %d is zero",
1256 		    current_line_number, partition);
1257 	    break;
1258 	}
1259 
1260 	dos(partp);
1261 	status = 1;
1262 	break;
1263     }
1264     return (status);
1265 }
1266 
1267 
1268 static int
1269 process_active(CMD *command)
1270 {
1271     int				status = 0, partition, i;
1272     struct dos_partition	*partp;
1273 
1274 	while (1) {
1275 	active_processed = 1;
1276 		if (command->n_args != 1) {
1277 	    warnx("ERROR line %d: incorrect number of active args",
1278 		    current_line_number);
1279 	    status = 0;
1280 	    break;
1281 	}
1282 	partition = command->args[0].arg_val;
1283 		if (partition < 1 || partition > 4) {
1284 	    warnx("ERROR line %d: invalid partition number %d",
1285 		    current_line_number, partition);
1286 	    break;
1287 	}
1288 	/*
1289 	 * Reset active partition
1290 	 */
1291 	partp = mboot.parts;
1292 	for (i = 0; i < NDOSPART; i++)
1293 	    partp[i].dp_flag = 0;
1294 	partp[partition-1].dp_flag = ACTIVE;
1295 
1296 	status = 1;
1297 	break;
1298     }
1299     return (status);
1300 }
1301 
1302 
1303 static int
1304 process_line(char *line)
1305 {
1306     CMD		command;
1307     int		status = 1;
1308 
1309 	while (1) {
1310 	parse_config_line(line, &command);
1311 		switch (command.cmd) {
1312 	case 0:
1313 	    /*
1314 	     * Comment or blank line
1315 	     */
1316 	    break;
1317 	case 'g':
1318 	    /*
1319 	     * Set geometry
1320 	     */
1321 	    status = process_geometry(&command);
1322 	    break;
1323 	case 'p':
1324 	    status = process_partition(&command);
1325 	    break;
1326 	case 'a':
1327 	    status = process_active(&command);
1328 	    break;
1329 	default:
1330 	    status = 0;
1331 	    break;
1332 	}
1333 	break;
1334     }
1335     return (status);
1336 }
1337 
1338 
1339 static int
1340 read_config(char *config_file)
1341 {
1342     FILE	*fp = NULL;
1343     int		status = 1;
1344     char	buf[1010];
1345 
1346 	while (1) {
1347 		if (strcmp(config_file, "-") != 0) {
1348 	    /*
1349 	     * We're not reading from stdin
1350 	     */
1351 			if ((fp = fopen(config_file, "r")) == NULL) {
1352 		status = 0;
1353 		break;
1354 	    }
1355 		} else {
1356 	    fp = stdin;
1357 	}
1358 	current_line_number = 0;
1359 		while (!feof(fp)) {
1360 	    if (fgets(buf, sizeof(buf), fp) == NULL)
1361 		break;
1362 	    ++current_line_number;
1363 	    status = process_line(buf);
1364 	    if (status == 0)
1365 		break;
1366 	    }
1367 	break;
1368     }
1369 	if (fp) {
1370 	/*
1371 	 * It doesn't matter if we're reading from stdin, as we've reached EOF
1372 	 */
1373 	fclose(fp);
1374     }
1375     return (status);
1376 }
1377 
1378 
1379 static void
1380 reset_boot(void)
1381 {
1382     int				i;
1383     struct dos_partition	*partp;
1384 
1385     init_boot();
1386     for (i = 0; i < 4; ++i) {
1387 	partp = &mboot.parts[i];
1388 	bzero(partp, sizeof(*partp));
1389     }
1390 }
1391 
1392 static int
1393 sanitize_partition(struct dos_partition *partp)
1394 {
1395     u_int32_t			prev_head_boundary, prev_cyl_boundary;
1396     u_int32_t			max_end, size, start;
1397 
1398     start = partp->dp_start;
1399     size = partp->dp_size;
1400     max_end = start + size;
1401     /* Only allow a zero size if the partition is being marked unused. */
1402     if (size == 0) {
1403 	if (start == 0 && partp->dp_typ == 0)
1404 	    return (1);
1405 	warnx("ERROR: size of partition is zero");
1406 	return (0);
1407     }
1408     /* Return if no adjustment is necessary. */
1409     if (start % dos_sectors == 0 && (start + size) % dos_sectors == 0)
1410 	return (1);
1411 
1412     if (start == 0) {
1413 	    warnx("WARNING: partition overlaps with partition table");
1414 	    if (ok("Correct this automatically?"))
1415 		    start = dos_sectors;
1416     }
1417     if (start % dos_sectors != 0)
1418 	warnx("WARNING: partition does not start on a head boundary");
1419     if ((start  +size) % dos_sectors != 0)
1420 	warnx("WARNING: partition does not end on a cylinder boundary");
1421     warnx("WARNING: this may confuse the BIOS or some operating systems");
1422     if (!ok("Correct this automatically?"))
1423 	return (1);
1424 
1425     /*
1426      * Adjust start upwards, if necessary, to fall on a head boundary.
1427      */
1428     if (start % dos_sectors != 0) {
1429 	prev_head_boundary = start / dos_sectors * dos_sectors;
1430 	if (max_end < dos_sectors ||
1431 	    prev_head_boundary >= max_end - dos_sectors) {
1432 	    /*
1433 	     * Can't go past end of partition
1434 	     */
1435 	    warnx(
1436     "ERROR: unable to adjust start of partition to fall on a head boundary");
1437 	    return (0);
1438         }
1439 	start = prev_head_boundary + dos_sectors;
1440     }
1441 
1442     /*
1443      * Adjust size downwards, if necessary, to fall on a cylinder
1444      * boundary.
1445      */
1446     prev_cyl_boundary = ((start + size) / dos_cylsecs) * dos_cylsecs;
1447     if (prev_cyl_boundary > start)
1448 	size = prev_cyl_boundary - start;
1449     else {
1450 	warnx("ERROR: could not adjust partition to start on a head boundary\n\
1451     and end on a cylinder boundary.");
1452 	return (0);
1453     }
1454 
1455     /* Finally, commit any changes to partp and return. */
1456     if (start != partp->dp_start) {
1457 	warnx("WARNING: adjusting start offset of partition to %u",
1458 	    (u_int)start);
1459 	partp->dp_start = start;
1460     }
1461     if (size != partp->dp_size) {
1462 	warnx("WARNING: adjusting size of partition to %u", (u_int)size);
1463 	partp->dp_size = size;
1464     }
1465 
1466     return (1);
1467 }
1468 
1469 /*
1470  * Try figuring out the root device's canonical disk name.
1471  * The following choices are considered:
1472  *   /dev/ad0s1a     => /dev/ad0
1473  *   /dev/da0a       => /dev/da0
1474  *   /dev/vinum/root => /dev/vinum/root
1475  * A ".eli" part is removed if it exists (see geli(8)).
1476  * A ".journal" ending is removed if it exists (see gjournal(8)).
1477  */
1478 static char *
1479 get_rootdisk(void)
1480 {
1481 	struct statfs rootfs;
1482 	regex_t re;
1483 #define NMATCHES 2
1484 	regmatch_t rm[NMATCHES];
1485 	char dev[PATH_MAX], *s;
1486 	int rv;
1487 
1488 	if (statfs("/", &rootfs) == -1)
1489 		err(1, "statfs(\"/\")");
1490 
1491 	if ((rv = regcomp(&re, "^(/dev/[a-z/]+[0-9]*)([sp][0-9]+)?[a-h]?(\\.journal)?$",
1492 		    REG_EXTENDED)) != 0)
1493 		errx(1, "regcomp() failed (%d)", rv);
1494 	strlcpy(dev, rootfs.f_mntfromname, sizeof (dev));
1495 	if ((s = strstr(dev, ".eli")) != NULL)
1496 	    memmove(s, s+4, strlen(s + 4) + 1);
1497 
1498 	if ((rv = regexec(&re, dev, NMATCHES, rm, 0)) != 0)
1499 		errx(1,
1500 "mounted root fs resource doesn't match expectations (regexec returned %d)",
1501 		    rv);
1502 	if ((s = malloc(rm[1].rm_eo - rm[1].rm_so + 1)) == NULL)
1503 		errx(1, "out of memory");
1504 	memcpy(s, rootfs.f_mntfromname + rm[1].rm_so,
1505 	    rm[1].rm_eo - rm[1].rm_so);
1506 	s[rm[1].rm_eo - rm[1].rm_so] = 0;
1507 
1508 	return s;
1509 }
1510