xref: /freebsd/sbin/fdisk/fdisk.c (revision e8643b01e6312a56d1e44a760fb4e95f0b10b54c)
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 static 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 MAX_SEC_SIZE 65536	/* maximum sector size that is supported */
71 #define MIN_SEC_SIZE 512	/* the sector size to start sensing at */
72 static int secsize = 0;		/* the sensed sector size */
73 
74 static char *disk;
75 
76 static int cyls, sectors, heads, cylsecs;
77 static u_int32_t disksecs;
78 
79 struct mboot {
80 	unsigned char *bootinst;  /* boot code */
81 	off_t bootinst_size;
82 	struct	dos_partition parts[NDOSPART];
83 };
84 
85 static struct mboot mboot;
86 static int fd;
87 
88 #define ACTIVE 0x80
89 
90 static uint dos_cyls;
91 static uint dos_heads;
92 static uint dos_sectors;
93 static uint dos_cylsecs;
94 
95 #define DOSSECT(s,c) ((s & 0x3f) | ((c >> 2) & 0xc0))
96 #define DOSCYL(c)	(c & 0xff)
97 
98 #define MAX_ARGS	10
99 
100 static int	current_line_number;
101 
102 static int	geom_processed = 0;
103 static int	part_processed = 0;
104 static int	active_processed = 0;
105 
106 typedef struct cmd {
107     char		cmd;
108     int			n_args;
109     struct arg {
110 	char		argtype;
111 	unsigned long	arg_val;
112 	char *		arg_str;
113     }			args[MAX_ARGS];
114 } CMD;
115 
116 static int B_flag  = 0;		/* replace boot code */
117 static int I_flag  = 0;		/* use entire disk for FreeBSD */
118 static int a_flag  = 0;		/* set active partition */
119 static char *b_flag = NULL;	/* path to boot code */
120 static int i_flag  = 0;		/* replace partition data */
121 static int q_flag  = 0;		/* Be quiet */
122 static int u_flag  = 0;		/* update partition data */
123 static int s_flag  = 0;		/* Print a summary and exit */
124 static int t_flag  = 0;		/* test only */
125 static char *f_flag = NULL;	/* Read config info from file */
126 static int v_flag  = 0;		/* Be verbose */
127 static int print_config_flag = 0;
128 
129 /*
130  * A list of partition types, probably outdated.
131  */
132 static const char *const part_types[256] = {
133 	[0x00] = "unused",
134 	[0x01] = "Primary DOS with 12 bit FAT",
135 	[0x02] = "XENIX / file system",
136 	[0x03] = "XENIX /usr file system",
137 	[0x04] = "Primary DOS with 16 bit FAT (< 32MB)",
138 	[0x05] = "Extended DOS",
139 	[0x06] = "Primary DOS, 16 bit FAT (>= 32MB)",
140 	[0x07] = "NTFS, OS/2 HPFS, QNX-2 (16 bit) or Advanced UNIX",
141 	[0x08] = "AIX file system or SplitDrive",
142 	[0x09] = "AIX boot partition or Coherent",
143 	[0x0A] = "OS/2 Boot Manager, OPUS or Coherent swap",
144 	[0x0B] = "DOS or Windows 95 with 32 bit FAT",
145 	[0x0C] = "DOS or Windows 95 with 32 bit FAT (LBA)",
146 	[0x0E] = "Primary 'big' DOS (>= 32MB, LBA)",
147 	[0x0F] = "Extended DOS (LBA)",
148 	[0x10] = "OPUS",
149 	[0x11] = "OS/2 BM: hidden DOS with 12-bit FAT",
150 	[0x12] = "Compaq diagnostics",
151 	[0x14] = "OS/2 BM: hidden DOS with 16-bit FAT (< 32MB)",
152 	[0x16] = "OS/2 BM: hidden DOS with 16-bit FAT (>= 32MB)",
153 	[0x17] = "OS/2 BM: hidden IFS (e.g. HPFS)",
154 	[0x18] = "AST Windows swapfile",
155 	[0x1b] = "ASUS Recovery partition (NTFS)",
156 	[0x24] = "NEC DOS",
157 	[0x3C] = "PartitionMagic recovery",
158 	[0x39] = "plan9",
159 	[0x40] = "VENIX 286",
160 	[0x41] = "Linux/MINIX (sharing disk with DRDOS)",
161 	[0x42] = "SFS or Linux swap (sharing disk with DRDOS)",
162 	[0x43] = "Linux native (sharing disk with DRDOS)",
163 	[0x4D] = "QNX 4.2 Primary",
164 	[0x4E] = "QNX 4.2 Secondary",
165 	[0x4F] = "QNX 4.2 Tertiary",
166 	[0x50] = "DM (disk manager)",
167 	[0x51] = "DM6 Aux1 (or Novell)",
168 	[0x52] = "CP/M or Microport SysV/AT",
169 	[0x53] = "DM6 Aux3",
170 	[0x54] = "DM6",
171 	[0x55] = "EZ-Drive (disk manager)",
172 	[0x56] = "Golden Bow (disk manager)",
173 	[0x5c] = "Priam Edisk (disk manager)", /* according to S. Widlake */
174 	[0x61] = "SpeedStor",
175 	[0x63] = "System V/386 (such as ISC UNIX), GNU HURD or Mach",
176 	[0x64] = "Novell Netware/286 2.xx",
177 	[0x65] = "Novell Netware/386 3.xx",
178 	[0x70] = "DiskSecure Multi-Boot",
179 	[0x75] = "PCIX",
180 	[0x77] = "QNX4.x",
181 	[0x78] = "QNX4.x 2nd part",
182 	[0x79] = "QNX4.x 3rd part",
183 	[0x80] = "Minix until 1.4a",
184 	[0x81] = "Minix since 1.4b, early Linux partition or Mitac disk manager",
185 	[0x82] = "Linux swap or Solaris x86",
186 	[0x83] = "Linux native",
187 	[0x84] = "OS/2 hidden C: drive",
188 	[0x85] = "Linux extended",
189 	[0x86] = "NTFS volume set??",
190 	[0x87] = "NTFS volume set??",
191 	[0x93] = "Amoeba file system",
192 	[0x94] = "Amoeba bad block table",
193 	[0x9F] = "BSD/OS",
194 	[0xA0] = "Suspend to Disk",
195 	[0xA5] = "FreeBSD/NetBSD/386BSD",
196 	[0xA6] = "OpenBSD",
197 	[0xA7] = "NeXTSTEP",
198 	[0xA9] = "NetBSD",
199 	[0xAC] = "IBM JFS",
200 	[0xAF] = "HFS+",
201 	[0xB7] = "BSDI BSD/386 file system",
202 	[0xB8] = "BSDI BSD/386 swap",
203 	[0xBE] = "Solaris x86 boot",
204 	[0xBF] = "Solaris x86 (new)",
205 	[0xC1] = "DRDOS/sec with 12-bit FAT",
206 	[0xC4] = "DRDOS/sec with 16-bit FAT (< 32MB)",
207 	[0xC6] = "DRDOS/sec with 16-bit FAT (>= 32MB)",
208 	[0xC7] = "Syrinx",
209 	[0xDB] = "CP/M, Concurrent CP/M, Concurrent DOS or CTOS",
210 	[0xDE] = "DELL Utilities - FAT filesystem",
211 	[0xE1] = "DOS access or SpeedStor with 12-bit FAT extended partition",
212 	[0xE3] = "DOS R/O or SpeedStor",
213 	[0xE4] = "SpeedStor with 16-bit FAT extended partition < 1024 cyl.",
214 	[0xEB] = "BeOS file system",
215 	[0xEE] = "EFI GPT",
216 	[0xEF] = "EFI System Partition",
217 	[0xF1] = "SpeedStor",
218 	[0xF2] = "DOS 3.3+ Secondary",
219 	[0xF4] = "SpeedStor large partition",
220 	[0xFB] = "VMware VMFS",
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 int geom_class_available(const char *);
236 static void print_s0(void);
237 static void print_part(const struct dos_partition *);
238 static void init_sector0(unsigned long start);
239 static void init_boot(void);
240 static void change_part(int i);
241 static void print_params(void);
242 static void change_active(int which);
243 static void change_code(void);
244 static void get_params_to_use(void);
245 static char *get_rootdisk(void);
246 static void dos(struct dos_partition *partp);
247 static int open_disk(int flag);
248 static ssize_t read_disk(off_t sector, void *buf);
249 static int write_disk(off_t sector, void *buf);
250 static int get_params(void);
251 static int read_s0(void);
252 static int write_s0(void);
253 static int ok(const char *str);
254 static int decimal(const char *str, int *num, int deflt, uint32_t maxval);
255 static int read_config(char *config_file);
256 static void reset_boot(void);
257 static int sanitize_partition(struct dos_partition *);
258 static void usage(void);
259 
260 int
261 main(int argc, char *argv[])
262 {
263 	int	c, i;
264 	int	partition = -1;
265 	struct	dos_partition *partp;
266 
267 	while ((c = getopt(argc, argv, "BIab:f:ipqstuv1234")) != -1)
268 		switch (c) {
269 		case 'B':
270 			B_flag = 1;
271 			break;
272 		case 'I':
273 			I_flag = 1;
274 			break;
275 		case 'a':
276 			a_flag = 1;
277 			break;
278 		case 'b':
279 			b_flag = optarg;
280 			break;
281 		case 'f':
282 			f_flag = optarg;
283 			break;
284 		case 'i':
285 			i_flag = 1;
286 			break;
287 		case 'p':
288 			print_config_flag = 1;
289 			break;
290 		case 'q':
291 			q_flag = 1;
292 			break;
293 		case 's':
294 			s_flag = 1;
295 			break;
296 		case 't':
297 			t_flag = 1;
298 			break;
299 		case 'u':
300 			u_flag = 1;
301 			break;
302 		case 'v':
303 			v_flag = 1;
304 			break;
305 		case '1':
306 		case '2':
307 		case '3':
308 		case '4':
309 			partition = c - '0';
310 			break;
311 		default:
312 			usage();
313 		}
314 	if (f_flag || i_flag)
315 		u_flag = 1;
316 	if (t_flag)
317 		v_flag = 1;
318 	argc -= optind;
319 	argv += optind;
320 
321 	if (argc == 0) {
322 		disk = get_rootdisk();
323 	} else {
324 		disk = g_device_path(argv[0]);
325 		if (disk == NULL)
326 			err(1, "unable to get correct path for %s", argv[0]);
327 	}
328 	if (open_disk(u_flag) < 0)
329 		err(1, "cannot open disk %s", disk);
330 
331 	/* (abu)use mboot.bootinst to probe for the sector size */
332 	if ((mboot.bootinst = malloc(MAX_SEC_SIZE)) == NULL)
333 		err(1, "cannot allocate buffer to determine disk sector size");
334 	if (read_disk(0, mboot.bootinst) == -1)
335 		errx(1, "could not detect sector size");
336 	free(mboot.bootinst);
337 	mboot.bootinst = NULL;
338 
339 	if (print_config_flag) {
340 		if (read_s0())
341 			err(1, "read_s0");
342 
343 		printf("# %s\n", disk);
344 		printf("g c%d h%d s%d\n", dos_cyls, dos_heads, dos_sectors);
345 
346 		for (i = 0; i < NDOSPART; i++) {
347 			partp = &mboot.parts[i];
348 
349 			if (partp->dp_start == 0 && partp->dp_size == 0)
350 				continue;
351 
352 			printf("p %d 0x%02x %lu %lu\n", i + 1, partp->dp_typ,
353 			    (u_long)partp->dp_start, (u_long)partp->dp_size);
354 
355 			/* Fill flags for the partition. */
356 			if (partp->dp_flag & 0x80)
357 				printf("a %d\n", i + 1);
358 		}
359 		exit(0);
360 	}
361 	if (s_flag) {
362 		if (read_s0())
363 			err(1, "read_s0");
364 		printf("%s: %d cyl %d hd %d sec\n", disk, dos_cyls, dos_heads,
365 		    dos_sectors);
366 		printf("Part  %11s %11s Type Flags\n", "Start", "Size");
367 		for (i = 0; i < NDOSPART; i++) {
368 			partp = &mboot.parts[i];
369 			if (partp->dp_start == 0 && partp->dp_size == 0)
370 				continue;
371 			printf("%4d: %11lu %11lu 0x%02x 0x%02x\n", i + 1,
372 			    (u_long) partp->dp_start,
373 			    (u_long) partp->dp_size, partp->dp_typ,
374 			    partp->dp_flag);
375 		}
376 		exit(0);
377 	}
378 
379 	printf("******* Working on device %s *******\n",disk);
380 
381 	if (I_flag) {
382 		read_s0();
383 		reset_boot();
384 		partp = &mboot.parts[0];
385 		partp->dp_typ = DOSPTYP_386BSD;
386 		partp->dp_flag = ACTIVE;
387 		partp->dp_start = dos_sectors;
388 		partp->dp_size = rounddown(disksecs, dos_cylsecs) -
389 		    dos_sectors;
390 		dos(partp);
391 		if (v_flag)
392 			print_s0();
393 		if (!t_flag)
394 			write_s0();
395 		exit(0);
396 	}
397 	if (f_flag) {
398 	    if (read_s0() || i_flag)
399 		reset_boot();
400 	    if (!read_config(f_flag))
401 		exit(1);
402 	    if (v_flag)
403 		print_s0();
404 	    if (!t_flag)
405 		write_s0();
406 	} else {
407 	    if(u_flag)
408 		get_params_to_use();
409 	    else
410 		print_params();
411 
412 	    if (read_s0())
413 		init_sector0(dos_sectors);
414 
415 	    printf("Media sector size is %d\n", secsize);
416 	    printf("Warning: BIOS sector numbering starts with sector 1\n");
417 	    printf("Information from DOS bootblock is:\n");
418 	    if (partition == -1)
419 		for (i = 1; i <= NDOSPART; i++)
420 		    change_part(i);
421 	    else
422 		change_part(partition);
423 
424 	    if (u_flag || a_flag)
425 		change_active(partition);
426 
427 	    if (B_flag)
428 		change_code();
429 
430 	    if (u_flag || a_flag || B_flag) {
431 		if (!t_flag) {
432 		    printf("\nWe haven't changed the partition table yet.  ");
433 		    printf("This is your last chance.\n");
434 		}
435 		print_s0();
436 		if (!t_flag) {
437 		    if (ok("Should we write new partition table?"))
438 			write_s0();
439 		} else {
440 		    printf("\n-t flag specified -- partition table not written.\n");
441 		}
442 	    }
443 	}
444 
445 	exit(0);
446 }
447 
448 static void
449 usage()
450 {
451 	fprintf(stderr, "%s%s",
452 		"usage: fdisk [-BIaipqstu] [-b bootcode] [-1234] [disk]\n",
453  		"       fdisk -f configfile [-itv] [disk]\n");
454         exit(1);
455 }
456 
457 static void
458 print_s0(void)
459 {
460 	int	i;
461 
462 	print_params();
463 	printf("Information from DOS bootblock is:\n");
464 	for (i = 1; i <= NDOSPART; i++) {
465 		printf("%d: ", i);
466 		print_part(&mboot.parts[i - 1]);
467 	}
468 }
469 
470 static struct dos_partition mtpart;
471 
472 static void
473 print_part(const struct dos_partition *partp)
474 {
475 	u_int64_t part_mb;
476 
477 	if (!bcmp(partp, &mtpart, sizeof (struct dos_partition))) {
478 		printf("<UNUSED>\n");
479 		return;
480 	}
481 	/*
482 	 * Be careful not to overflow.
483 	 */
484 	part_mb = partp->dp_size;
485 	part_mb *= secsize;
486 	part_mb /= (1024 * 1024);
487 	printf("sysid %d (%#04x),(%s)\n", partp->dp_typ, partp->dp_typ,
488 	    get_type(partp->dp_typ));
489 	printf("    start %lu, size %lu (%ju Meg), flag %x%s\n",
490 		(u_long)partp->dp_start,
491 		(u_long)partp->dp_size,
492 		(uintmax_t)part_mb,
493 		partp->dp_flag,
494 		partp->dp_flag == ACTIVE ? " (active)" : "");
495 	printf("\tbeg: cyl %d/ head %d/ sector %d;\n\tend: cyl %d/ head %d/ sector %d\n"
496 		,DPCYL(partp->dp_scyl, partp->dp_ssect)
497 		,partp->dp_shd
498 		,DPSECT(partp->dp_ssect)
499 		,DPCYL(partp->dp_ecyl, partp->dp_esect)
500 		,partp->dp_ehd
501 		,DPSECT(partp->dp_esect));
502 }
503 
504 
505 static void
506 init_boot(void)
507 {
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 (sb.st_size == 0)
517 		errx(1, "%s is empty, must not be.", fname);
518 	if ((mboot.bootinst_size = sb.st_size) % secsize != 0)
519 		errx(1, "%s: length must be a multiple of sector size", fname);
520 	if (mboot.bootinst != NULL)
521 		free(mboot.bootinst);
522 	if ((mboot.bootinst = malloc(mboot.bootinst_size = sb.st_size)) == NULL)
523 		errx(1, "%s: unable to allocate read buffer", fname);
524 	if ((n = read(fdesc, mboot.bootinst, mboot.bootinst_size)) == -1 ||
525 	    close(fdesc))
526 		err(1, "%s", fname);
527 	if (n != mboot.bootinst_size)
528 		errx(1, "%s: short read", fname);
529 }
530 
531 
532 static void
533 init_sector0(unsigned long start)
534 {
535 	struct dos_partition *partp = &mboot.parts[0];
536 
537 	init_boot();
538 
539 	partp->dp_typ = DOSPTYP_386BSD;
540 	partp->dp_flag = ACTIVE;
541 	start = roundup(start, dos_sectors);
542 	if(start == 0)
543 		start = dos_sectors;
544 	partp->dp_start = start;
545 	partp->dp_size = rounddown(disksecs, dos_cylsecs) - start;
546 
547 	dos(partp);
548 }
549 
550 static void
551 change_part(int i)
552 {
553     struct dos_partition *partp = &mboot.parts[i - 1];
554 
555     printf("The data for partition %d is:\n", i);
556     print_part(partp);
557 
558     if (u_flag && ok("Do you want to change it?")) {
559 	int tmp;
560 
561 	if (i_flag) {
562 	    bzero(partp, sizeof (*partp));
563 	    if (i == 1) {
564 		init_sector0(1);
565 		printf("\nThe static data for the slice 1 has been reinitialized to:\n");
566 		print_part(partp);
567 	    }
568 	}
569 
570 	do {
571 		Decimal("sysid (165=FreeBSD)", partp->dp_typ, tmp, 255);
572 		Decimal("start", partp->dp_start, tmp, NO_DISK_SECTORS);
573 		Decimal("size", partp->dp_size, tmp, NO_DISK_SECTORS);
574 		if (!sanitize_partition(partp)) {
575 			warnx("ERROR: failed to adjust; setting sysid to 0");
576 			partp->dp_typ = 0;
577 		}
578 
579 		if (ok("Explicitly specify beg/end address ?"))
580 		{
581 			int	tsec,tcyl,thd;
582 			tcyl = DPCYL(partp->dp_scyl,partp->dp_ssect);
583 			thd = partp->dp_shd;
584 			tsec = DPSECT(partp->dp_ssect);
585 			Decimal("beginning cylinder", tcyl, tmp, NO_TRACK_CYLINDERS);
586 			Decimal("beginning head", thd, tmp, NO_TRACK_HEADS);
587 			Decimal("beginning sector", tsec, tmp, NO_TRACK_SECTORS);
588 			partp->dp_scyl = DOSCYL(tcyl);
589 			partp->dp_ssect = DOSSECT(tsec,tcyl);
590 			partp->dp_shd = thd;
591 
592 			tcyl = DPCYL(partp->dp_ecyl,partp->dp_esect);
593 			thd = partp->dp_ehd;
594 			tsec = DPSECT(partp->dp_esect);
595 			Decimal("ending cylinder", tcyl, tmp, NO_TRACK_CYLINDERS);
596 			Decimal("ending head", thd, tmp, NO_TRACK_HEADS);
597 			Decimal("ending sector", tsec, tmp, NO_TRACK_SECTORS);
598 			partp->dp_ecyl = DOSCYL(tcyl);
599 			partp->dp_esect = DOSSECT(tsec,tcyl);
600 			partp->dp_ehd = thd;
601 		} else
602 			dos(partp);
603 
604 		print_part(partp);
605 	} while (!ok("Are we happy with this entry?"));
606     }
607 }
608 
609 static void
610 print_params()
611 {
612 	printf("parameters extracted from in-core disklabel are:\n");
613 	printf("cylinders=%d heads=%d sectors/track=%d (%d blks/cyl)\n\n"
614 			,cyls,heads,sectors,cylsecs);
615 	if (dos_cyls > 1023 || dos_heads > 255 || dos_sectors > 63)
616 		printf("Figures below won't work with BIOS for partitions not in cyl 1\n");
617 	printf("parameters to be used for BIOS calculations are:\n");
618 	printf("cylinders=%d heads=%d sectors/track=%d (%d blks/cyl)\n\n"
619 		,dos_cyls,dos_heads,dos_sectors,dos_cylsecs);
620 }
621 
622 static void
623 change_active(int which)
624 {
625 	struct dos_partition *partp = &mboot.parts[0];
626 	int active, i, new, tmp;
627 
628 	active = -1;
629 	for (i = 0; i < NDOSPART; i++) {
630 		if ((partp[i].dp_flag & ACTIVE) == 0)
631 			continue;
632 		printf("Partition %d is marked active\n", i + 1);
633 		if (active == -1)
634 			active = i + 1;
635 	}
636 	if (a_flag && which != -1)
637 		active = which;
638 	else if (active == -1)
639 		active = 1;
640 
641 	if (!ok("Do you want to change the active partition?"))
642 		return;
643 setactive:
644 	do {
645 		new = active;
646 		Decimal("active partition", new, tmp, 0);
647 		if (new < 1 || new > 4) {
648 			printf("Active partition number must be in range 1-4."
649 					"  Try again.\n");
650 			goto setactive;
651 		}
652 		active = new;
653 	} while (!ok("Are you happy with this choice"));
654 	for (i = 0; i < NDOSPART; i++)
655 		partp[i].dp_flag = 0;
656 	if (active > 0 && active <= NDOSPART)
657 		partp[active-1].dp_flag = ACTIVE;
658 }
659 
660 static void
661 change_code()
662 {
663 	if (ok("Do you want to change the boot code?"))
664 		init_boot();
665 }
666 
667 void
668 get_params_to_use()
669 {
670 	int	tmp;
671 	print_params();
672 	if (ok("Do you want to change our idea of what BIOS thinks ?"))
673 	{
674 		do
675 		{
676 			Decimal("BIOS's idea of #cylinders", dos_cyls, tmp, 0);
677 			Decimal("BIOS's idea of #heads", dos_heads, tmp, 0);
678 			Decimal("BIOS's idea of #sectors", dos_sectors, tmp, 0);
679 			dos_cylsecs = dos_heads * dos_sectors;
680 			print_params();
681 		}
682 		while(!ok("Are you happy with this choice"));
683 	}
684 }
685 
686 
687 /***********************************************\
688 * Change real numbers into strange dos numbers	*
689 \***********************************************/
690 static void
691 dos(struct dos_partition *partp)
692 {
693 	int cy, sec;
694 	u_int32_t end;
695 
696 	if (partp->dp_typ == 0 && partp->dp_start == 0 && partp->dp_size == 0) {
697 		memcpy(partp, &mtpart, sizeof(*partp));
698 		return;
699 	}
700 
701 	/* Start c/h/s. */
702 	partp->dp_shd = partp->dp_start % dos_cylsecs / dos_sectors;
703 	cy = partp->dp_start / dos_cylsecs;
704 	sec = partp->dp_start % dos_sectors + 1;
705 	partp->dp_scyl = DOSCYL(cy);
706 	partp->dp_ssect = DOSSECT(sec, cy);
707 
708 	/* End c/h/s. */
709 	end = partp->dp_start + partp->dp_size - 1;
710 	partp->dp_ehd = end % dos_cylsecs / dos_sectors;
711 	cy = end / dos_cylsecs;
712 	sec = end % dos_sectors + 1;
713 	partp->dp_ecyl = DOSCYL(cy);
714 	partp->dp_esect = DOSSECT(sec, cy);
715 }
716 
717 static int
718 open_disk(int flag)
719 {
720 	int rwmode;
721 
722 	/* Write mode if one of these flags are set. */
723 	rwmode = (a_flag || I_flag || B_flag || flag);
724 	fd = g_open(disk, rwmode);
725 	/* If the mode fails, try read-only if we didn't. */
726 	if (fd == -1 && errno == EPERM && rwmode)
727 		fd = g_open(disk, 0);
728 	if (fd == -1 && errno == ENXIO)
729 		return -2;
730 	if (fd == -1) {
731 		warnx("can't open device %s", disk);
732 		return -1;
733 	}
734 	if (get_params() == -1) {
735 		warnx("can't get disk parameters on %s", disk);
736 		return -1;
737 	}
738 	return fd;
739 }
740 
741 static ssize_t
742 read_disk(off_t sector, void *buf)
743 {
744 
745 	lseek(fd, (sector * 512), 0);
746 	if (secsize == 0)
747 		for (secsize = MIN_SEC_SIZE; secsize <= MAX_SEC_SIZE;
748 		     secsize *= 2) {
749 			/* try the read */
750 			int size = read(fd, buf, secsize);
751 			if (size == secsize)
752 				/* it worked so return */
753 				return secsize;
754 		}
755 	else
756 		return read(fd, buf, secsize);
757 
758 	/* we failed to read at any of the sizes */
759 	return -1;
760 }
761 
762 static int
763 geom_class_available(const char *name)
764 {
765 	struct gclass *class;
766 	struct gmesh mesh;
767 	int error;
768 
769 	error = geom_gettree(&mesh);
770 	if (error != 0)
771 		errc(1, error, "Cannot get GEOM tree");
772 
773 	LIST_FOREACH(class, &mesh.lg_class, lg_class) {
774 		if (strcmp(class->lg_name, name) == 0) {
775 			geom_deletetree(&mesh);
776 			return (1);
777 		}
778 	}
779 
780 	geom_deletetree(&mesh);
781 
782 	return (0);
783 }
784 
785 static int
786 write_disk(off_t sector, void *buf)
787 {
788 	struct gctl_req *grq;
789 	const char *errmsg;
790 	char *pname;
791 	int error;
792 
793 	/* Check that GEOM_MBR is available */
794 	if (geom_class_available("MBR") != 0) {
795 		grq = gctl_get_handle();
796 		gctl_ro_param(grq, "verb", -1, "write MBR");
797 		gctl_ro_param(grq, "class", -1, "MBR");
798 		pname = g_providername(fd);
799 		if (pname == NULL) {
800 			warn("Error getting providername for %s", disk);
801 			return (-1);
802 		}
803 		gctl_ro_param(grq, "geom", -1, pname);
804 		gctl_ro_param(grq, "data", secsize, buf);
805 		errmsg = gctl_issue(grq);
806 		free(pname);
807 		if (errmsg == NULL) {
808 			gctl_free(grq);
809 			return(0);
810 		}
811 		if (!q_flag)
812 			warnx("GEOM_MBR: %s", errmsg);
813 		gctl_free(grq);
814 	} else {
815 		/*
816 		 * Try to write MBR directly. This may help when disk
817 		 * is not in use.
818 		 * XXX: hardcoded sectorsize
819 		 */
820 		error = pwrite(fd, buf, secsize, (sector * 512));
821 		if (error == secsize)
822 			return (0);
823 	}
824 
825 	/*
826 	 * GEOM_MBR is not available or failed to write MBR.
827 	 * Now check that we have GEOM_PART and recommend to use gpart (8).
828 	 */
829 	if (geom_class_available("PART") != 0)
830 		warnx("Failed to write MBR. Try to use gpart(8).");
831 	else
832 		warnx("Failed to write sector zero");
833 	return(EINVAL);
834 }
835 
836 static int
837 get_params()
838 {
839 	int error;
840 	u_int u;
841 	off_t o;
842 
843 	error = ioctl(fd, DIOCGFWSECTORS, &u);
844 	if (error == 0)
845 		sectors = dos_sectors = u;
846 	else
847 		sectors = dos_sectors = 63;
848 
849 	error = ioctl(fd, DIOCGFWHEADS, &u);
850 	if (error == 0)
851 		heads = dos_heads = u;
852 	else
853 		heads = dos_heads = 255;
854 
855 	dos_cylsecs = cylsecs = heads * sectors;
856 	disksecs = cyls * heads * sectors;
857 
858 	u = g_sectorsize(fd);
859 	if (u <= 0)
860 		return (-1);
861 
862 	o = g_mediasize(fd);
863 	if (o < 0)
864 		return (-1);
865 	if (o / u <= NO_DISK_SECTORS)
866 		disksecs = o / u;
867 	else
868 		disksecs = NO_DISK_SECTORS;
869 	cyls = dos_cyls = o / (u * dos_heads * dos_sectors);
870 
871 	return (0);
872 }
873 
874 static int
875 read_s0()
876 {
877 	int i;
878 
879 	mboot.bootinst_size = secsize;
880 	if (mboot.bootinst != NULL)
881 		free(mboot.bootinst);
882 	if ((mboot.bootinst = malloc(mboot.bootinst_size)) == NULL) {
883 		warnx("unable to allocate buffer to read fdisk "
884 		      "partition table");
885 		return -1;
886 	}
887 	if (read_disk(0, mboot.bootinst) == -1) {
888 		warnx("can't read fdisk partition table");
889 		return -1;
890 	}
891 	if (le16dec(&mboot.bootinst[DOSMAGICOFFSET]) != DOSMAGIC) {
892 		warnx("invalid fdisk partition table found");
893 		/* So should we initialize things */
894 		return -1;
895 	}
896 	for (i = 0; i < NDOSPART; i++)
897 		dos_partition_dec(
898 		    &mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
899 		    &mboot.parts[i]);
900 	return 0;
901 }
902 
903 static int
904 write_s0()
905 {
906 	int	sector, i;
907 
908 	if (iotest) {
909 		print_s0();
910 		return 0;
911 	}
912 	for(i = 0; i < NDOSPART; i++)
913 		dos_partition_enc(&mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
914 		    &mboot.parts[i]);
915 	le16enc(&mboot.bootinst[DOSMAGICOFFSET], DOSMAGIC);
916 	for(sector = 0; sector < mboot.bootinst_size / secsize; sector++)
917 		if (write_disk(sector,
918 			       &mboot.bootinst[sector * secsize]) == -1) {
919 			warn("can't write fdisk partition table");
920 			return -1;
921 		}
922 	return(0);
923 }
924 
925 
926 static int
927 ok(const char *str)
928 {
929 	printf("%s [n] ", str);
930 	fflush(stdout);
931 	if (fgets(lbuf, LBUF, stdin) == NULL)
932 		exit(1);
933 	lbuf[strlen(lbuf)-1] = 0;
934 
935 	if (*lbuf &&
936 		(!strcmp(lbuf, "yes") || !strcmp(lbuf, "YES") ||
937 		 !strcmp(lbuf, "y") || !strcmp(lbuf, "Y")))
938 		return 1;
939 	else
940 		return 0;
941 }
942 
943 static int
944 decimal(const char *str, int *num, int deflt, uint32_t maxval)
945 {
946 	long long acc;
947 	int c;
948 	char *cp;
949 
950 	while (1) {
951 		acc = 0;
952 		printf("Supply a decimal value for \"%s\" [%d] ", str, deflt);
953 		fflush(stdout);
954 		if (fgets(lbuf, LBUF, stdin) == NULL)
955 			exit(1);
956 		lbuf[strlen(lbuf)-1] = 0;
957 
958 		if (!*lbuf)
959 			return 0;
960 
961 		cp = lbuf;
962 		while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
963 		if (!c)
964 			return 0;
965 		while ((c = *cp++)) {
966 			if (c <= '9' && c >= '0') {
967 				if (acc <= maxval || maxval == 0)
968 					acc = acc * 10 + c - '0';
969 			} else
970 				break;
971 		}
972 		if (c == ' ' || c == '\t')
973 			while ((c = *cp) && (c == ' ' || c == '\t')) cp++;
974 		if (!c) {
975 			if (maxval > 0 && acc > maxval) {
976 				acc = maxval;
977 				printf("%s exceeds maximum value allowed for "
978 				  "this field. The value has been reduced "
979 				  "to %lld\n", lbuf, acc);
980 			}
981 			*num = acc;
982 			return 1;
983 		} else
984 			printf("%s is an invalid decimal number.  Try again.\n",
985 				lbuf);
986 	}
987 }
988 
989 
990 static void
991 parse_config_line(char *line, CMD *command)
992 {
993     char	*cp, *end;
994 
995     cp = line;
996     while (1) {
997 	memset(command, 0, sizeof(*command));
998 
999 	while (isspace(*cp)) ++cp;
1000 	if (*cp == '\0' || *cp == '#')
1001 	    break;
1002 	command->cmd = *cp++;
1003 
1004 	/*
1005 	 * Parse args
1006 	 */
1007 	    while (1) {
1008 	    while (isspace(*cp)) ++cp;
1009 	    if (*cp == '\0')
1010 		break;		/* eol */
1011 	    if (*cp == '#')
1012 		break;		/* found comment */
1013 	    if (isalpha(*cp))
1014 		command->args[command->n_args].argtype = *cp++;
1015 	    end = NULL;
1016 	    command->args[command->n_args].arg_val = strtoul(cp, &end, 0);
1017  	    if (cp == end || (!isspace(*end) && *end != '\0')) {
1018  		char ch;
1019  		end = cp;
1020  		while (!isspace(*end) && *end != '\0') ++end;
1021  		ch = *end; *end = '\0';
1022  		command->args[command->n_args].arg_str = strdup(cp);
1023  		*end = ch;
1024  	    } else
1025  		command->args[command->n_args].arg_str = NULL;
1026 	    cp = end;
1027 	    command->n_args++;
1028 	}
1029 	break;
1030     }
1031 }
1032 
1033 
1034 static int
1035 process_geometry(CMD *command)
1036 {
1037     int		status = 1, i;
1038 
1039     while (1) {
1040 	geom_processed = 1;
1041 	    if (part_processed) {
1042 	    warnx(
1043 	"ERROR line %d: the geometry specification line must occur before\n\
1044     all partition specifications",
1045 		    current_line_number);
1046 	    status = 0;
1047 	    break;
1048 	}
1049 	    if (command->n_args != 3) {
1050 	    warnx("ERROR line %d: incorrect number of geometry args",
1051 		    current_line_number);
1052 	    status = 0;
1053 	    break;
1054 	}
1055 	    dos_cyls = 0;
1056 	    dos_heads = 0;
1057 	    dos_sectors = 0;
1058 	    for (i = 0; i < 3; ++i) {
1059 		    switch (command->args[i].argtype) {
1060 	    case 'c':
1061 		dos_cyls = command->args[i].arg_val;
1062 		break;
1063 	    case 'h':
1064 		dos_heads = command->args[i].arg_val;
1065 		break;
1066 	    case 's':
1067 		dos_sectors = command->args[i].arg_val;
1068 		break;
1069 	    default:
1070 		warnx(
1071 		"ERROR line %d: unknown geometry arg type: '%c' (0x%02x)",
1072 			current_line_number, command->args[i].argtype,
1073 			command->args[i].argtype);
1074 		status = 0;
1075 		break;
1076 	    }
1077 	}
1078 	if (status == 0)
1079 	    break;
1080 
1081 	dos_cylsecs = dos_heads * dos_sectors;
1082 
1083 	/*
1084 	 * Do sanity checks on parameter values
1085 	 */
1086 	    if (dos_cyls == 0) {
1087 	    warnx("ERROR line %d: number of cylinders not specified",
1088 		    current_line_number);
1089 	    status = 0;
1090 	}
1091 	    if (dos_cyls > 1024) {
1092 	    warnx(
1093 	"WARNING line %d: number of cylinders (%d) may be out-of-range\n\
1094     (must be within 1-1024 for normal BIOS operation, unless the entire disk\n\
1095     is dedicated to FreeBSD)",
1096 		    current_line_number, dos_cyls);
1097 	}
1098 
1099 	    if (dos_heads == 0) {
1100 	    warnx("ERROR line %d: number of heads not specified",
1101 		    current_line_number);
1102 	    status = 0;
1103 	    } else if (dos_heads > 256) {
1104 	    warnx("ERROR line %d: number of heads must be within (1-256)",
1105 		    current_line_number);
1106 	    status = 0;
1107 	}
1108 
1109 	    if (dos_sectors == 0) {
1110 	    warnx("ERROR line %d: number of sectors not specified",
1111 		    current_line_number);
1112 	    status = 0;
1113 	    } else if (dos_sectors > 63) {
1114 	    warnx("ERROR line %d: number of sectors must be within (1-63)",
1115 		    current_line_number);
1116 	    status = 0;
1117 	}
1118 
1119 	break;
1120     }
1121     return (status);
1122 }
1123 
1124 static u_int32_t
1125 str2sectors(const char *str)
1126 {
1127 	char *end;
1128 	unsigned long val;
1129 
1130 	val = strtoul(str, &end, 0);
1131 	if (str == end || *end == '\0') {
1132 		warnx("ERROR line %d: unexpected size: \'%s\'",
1133 		    current_line_number, str);
1134 		return NO_DISK_SECTORS;
1135 	}
1136 
1137 	if (*end == 'K')
1138 		val *= 1024UL / secsize;
1139 	else if (*end == 'M')
1140 		val *= 1024UL * 1024UL / secsize;
1141 	else if (*end == 'G')
1142 		val *= 1024UL * 1024UL * 1024UL / secsize;
1143 	else {
1144 		warnx("ERROR line %d: unexpected modifier: %c "
1145 		    "(not K/M/G)", current_line_number, *end);
1146 		return NO_DISK_SECTORS;
1147 	}
1148 
1149 	return val;
1150 }
1151 
1152 static int
1153 process_partition(CMD *command)
1154 {
1155     int				status = 0, partition;
1156     u_int32_t			prev_head_boundary, prev_cyl_boundary;
1157     u_int32_t			adj_size, max_end;
1158     struct dos_partition	*partp;
1159 
1160 	while (1) {
1161 	part_processed = 1;
1162 		if (command->n_args != 4) {
1163 	    warnx("ERROR line %d: incorrect number of partition args",
1164 		    current_line_number);
1165 	    break;
1166 	}
1167 	partition = command->args[0].arg_val;
1168 		if (partition < 1 || partition > 4) {
1169 	    warnx("ERROR line %d: invalid partition number %d",
1170 		    current_line_number, partition);
1171 	    break;
1172 	}
1173 	partp = &mboot.parts[partition - 1];
1174 	bzero(partp, sizeof (*partp));
1175 	partp->dp_typ = command->args[1].arg_val;
1176 	if (command->args[2].arg_str != NULL) {
1177 		if (strcmp(command->args[2].arg_str, "*") == 0) {
1178 			int i;
1179 			partp->dp_start = dos_sectors;
1180 			for (i = 1; i < partition; i++) {
1181     				struct dos_partition *prev_partp;
1182 				prev_partp = ((struct dos_partition *)
1183 				    &mboot.parts) + i - 1;
1184 				if (prev_partp->dp_typ != 0)
1185 					partp->dp_start = prev_partp->dp_start +
1186 					    prev_partp->dp_size;
1187 			}
1188 			if (partp->dp_start % dos_sectors != 0) {
1189 				prev_head_boundary = rounddown(partp->dp_start,
1190 				    dos_sectors);
1191 		    		partp->dp_start = prev_head_boundary +
1192 				    dos_sectors;
1193 			}
1194 		} else {
1195 			partp->dp_start = str2sectors(command->args[2].arg_str);
1196 			if (partp->dp_start == NO_DISK_SECTORS)
1197 				break;
1198 		}
1199 	} else
1200 		partp->dp_start = command->args[2].arg_val;
1201 
1202 	if (command->args[3].arg_str != NULL) {
1203 		if (strcmp(command->args[3].arg_str, "*") == 0)
1204 			partp->dp_size = rounddown(disksecs, dos_cylsecs) -
1205 			    partp->dp_start;
1206 		else {
1207 			partp->dp_size = str2sectors(command->args[3].arg_str);
1208 			if (partp->dp_size == NO_DISK_SECTORS)
1209 				break;
1210 		}
1211 		prev_cyl_boundary = rounddown(partp->dp_start + partp->dp_size,
1212 		    dos_cylsecs);
1213 		if (prev_cyl_boundary > partp->dp_start)
1214 			partp->dp_size = prev_cyl_boundary - partp->dp_start;
1215 	} else
1216 		partp->dp_size = command->args[3].arg_val;
1217 
1218 	max_end = partp->dp_start + partp->dp_size;
1219 
1220 	if (partp->dp_typ == 0) {
1221 	    /*
1222 	     * Get out, the partition is marked as unused.
1223 	     */
1224 	    /*
1225 	     * Insure that it's unused.
1226 	     */
1227 	    bzero(partp, sizeof(*partp));
1228 	    status = 1;
1229 	    break;
1230 	}
1231 
1232 	/*
1233 	 * Adjust start upwards, if necessary, to fall on a head boundary.
1234 	 */
1235 		if (partp->dp_start % dos_sectors != 0) {
1236 	    prev_head_boundary = rounddown(partp->dp_start, dos_sectors);
1237 	    if (max_end < dos_sectors ||
1238 			    prev_head_boundary > max_end - dos_sectors) {
1239 		/*
1240 		 * Can't go past end of partition
1241 		 */
1242 		warnx(
1243 	"ERROR line %d: unable to adjust start of partition %d to fall on\n\
1244     a head boundary",
1245 			current_line_number, partition);
1246 		break;
1247 	    }
1248 	    warnx(
1249 	"WARNING: adjusting start offset of partition %d\n\
1250     from %u to %u, to fall on a head boundary",
1251 		    partition, (u_int)partp->dp_start,
1252 		    (u_int)(prev_head_boundary + dos_sectors));
1253 	    partp->dp_start = prev_head_boundary + dos_sectors;
1254 	}
1255 
1256 	/*
1257 	 * Adjust size downwards, if necessary, to fall on a cylinder
1258 	 * boundary.
1259 	 */
1260 	prev_cyl_boundary = rounddown(partp->dp_start + partp->dp_size,
1261 	    dos_cylsecs);
1262 	if (prev_cyl_boundary > partp->dp_start)
1263 	    adj_size = prev_cyl_boundary - partp->dp_start;
1264 		else {
1265 	    warnx(
1266 	"ERROR: could not adjust partition to start on a head boundary\n\
1267     and end on a cylinder boundary.");
1268 	    return (0);
1269 	}
1270 		if (adj_size != partp->dp_size) {
1271 	    warnx(
1272 	"WARNING: adjusting size of partition %d from %u to %u\n\
1273     to end on a cylinder boundary",
1274 		    partition, (u_int)partp->dp_size, (u_int)adj_size);
1275 	    partp->dp_size = adj_size;
1276 	}
1277 		if (partp->dp_size == 0) {
1278 	    warnx("ERROR line %d: size of partition %d is zero",
1279 		    current_line_number, partition);
1280 	    break;
1281 	}
1282 
1283 	dos(partp);
1284 	status = 1;
1285 	break;
1286     }
1287     return (status);
1288 }
1289 
1290 
1291 static int
1292 process_active(CMD *command)
1293 {
1294     int				status = 0, partition, i;
1295     struct dos_partition	*partp;
1296 
1297 	while (1) {
1298 	active_processed = 1;
1299 		if (command->n_args != 1) {
1300 	    warnx("ERROR line %d: incorrect number of active args",
1301 		    current_line_number);
1302 	    status = 0;
1303 	    break;
1304 	}
1305 	partition = command->args[0].arg_val;
1306 		if (partition < 1 || partition > 4) {
1307 	    warnx("ERROR line %d: invalid partition number %d",
1308 		    current_line_number, partition);
1309 	    break;
1310 	}
1311 	/*
1312 	 * Reset active partition
1313 	 */
1314 	partp = mboot.parts;
1315 	for (i = 0; i < NDOSPART; i++)
1316 	    partp[i].dp_flag = 0;
1317 	partp[partition-1].dp_flag = ACTIVE;
1318 
1319 	status = 1;
1320 	break;
1321     }
1322     return (status);
1323 }
1324 
1325 
1326 static int
1327 process_line(char *line)
1328 {
1329     CMD		command;
1330     int		status = 1;
1331 
1332 	while (1) {
1333 	parse_config_line(line, &command);
1334 		switch (command.cmd) {
1335 	case 0:
1336 	    /*
1337 	     * Comment or blank line
1338 	     */
1339 	    break;
1340 	case 'g':
1341 	    /*
1342 	     * Set geometry
1343 	     */
1344 	    status = process_geometry(&command);
1345 	    break;
1346 	case 'p':
1347 	    status = process_partition(&command);
1348 	    break;
1349 	case 'a':
1350 	    status = process_active(&command);
1351 	    break;
1352 	default:
1353 	    status = 0;
1354 	    break;
1355 	}
1356 	break;
1357     }
1358     return (status);
1359 }
1360 
1361 
1362 static int
1363 read_config(char *config_file)
1364 {
1365     FILE	*fp = NULL;
1366     int		status = 1;
1367     char	buf[1010];
1368 
1369 	while (1) {
1370 		if (strcmp(config_file, "-") != 0) {
1371 	    /*
1372 	     * We're not reading from stdin
1373 	     */
1374 			if ((fp = fopen(config_file, "r")) == NULL) {
1375 		status = 0;
1376 		break;
1377 	    }
1378 		} else {
1379 	    fp = stdin;
1380 	}
1381 	current_line_number = 0;
1382 		while (!feof(fp)) {
1383 	    if (fgets(buf, sizeof(buf), fp) == NULL)
1384 		break;
1385 	    ++current_line_number;
1386 	    status = process_line(buf);
1387 	    if (status == 0)
1388 		break;
1389 	    }
1390 	break;
1391     }
1392 	if (fp) {
1393 	/*
1394 	 * It doesn't matter if we're reading from stdin, as we've reached EOF
1395 	 */
1396 	fclose(fp);
1397     }
1398     return (status);
1399 }
1400 
1401 
1402 static void
1403 reset_boot(void)
1404 {
1405     int				i;
1406     struct dos_partition	*partp;
1407 
1408     init_boot();
1409     for (i = 0; i < 4; ++i) {
1410 	partp = &mboot.parts[i];
1411 	bzero(partp, sizeof(*partp));
1412     }
1413 }
1414 
1415 static int
1416 sanitize_partition(struct dos_partition *partp)
1417 {
1418     u_int32_t			prev_head_boundary, prev_cyl_boundary;
1419     u_int32_t			max_end, size, start;
1420 
1421     start = partp->dp_start;
1422     size = partp->dp_size;
1423     max_end = start + size;
1424     /* Only allow a zero size if the partition is being marked unused. */
1425     if (size == 0) {
1426 	if (start == 0 && partp->dp_typ == 0)
1427 	    return (1);
1428 	warnx("ERROR: size of partition is zero");
1429 	return (0);
1430     }
1431     /* Return if no adjustment is necessary. */
1432     if (start % dos_sectors == 0 && (start + size) % dos_sectors == 0)
1433 	return (1);
1434 
1435     if (start == 0) {
1436 	    warnx("WARNING: partition overlaps with partition table");
1437 	    if (ok("Correct this automatically?"))
1438 		    start = dos_sectors;
1439     }
1440     if (start % dos_sectors != 0)
1441 	warnx("WARNING: partition does not start on a head boundary");
1442     if ((start  +size) % dos_sectors != 0)
1443 	warnx("WARNING: partition does not end on a cylinder boundary");
1444     warnx("WARNING: this may confuse the BIOS or some operating systems");
1445     if (!ok("Correct this automatically?"))
1446 	return (1);
1447 
1448     /*
1449      * Adjust start upwards, if necessary, to fall on a head boundary.
1450      */
1451     if (start % dos_sectors != 0) {
1452 	prev_head_boundary = rounddown(start, dos_sectors);
1453 	if (max_end < dos_sectors ||
1454 	    prev_head_boundary >= max_end - dos_sectors) {
1455 	    /*
1456 	     * Can't go past end of partition
1457 	     */
1458 	    warnx(
1459     "ERROR: unable to adjust start of partition to fall on a head boundary");
1460 	    return (0);
1461         }
1462 	start = prev_head_boundary + dos_sectors;
1463     }
1464 
1465     /*
1466      * Adjust size downwards, if necessary, to fall on a cylinder
1467      * boundary.
1468      */
1469     prev_cyl_boundary = rounddown(start + size, dos_cylsecs);
1470     if (prev_cyl_boundary > start)
1471 	size = prev_cyl_boundary - start;
1472     else {
1473 	warnx("ERROR: could not adjust partition to start on a head boundary\n\
1474     and end on a cylinder boundary.");
1475 	return (0);
1476     }
1477 
1478     /* Finally, commit any changes to partp and return. */
1479     if (start != partp->dp_start) {
1480 	warnx("WARNING: adjusting start offset of partition to %u",
1481 	    (u_int)start);
1482 	partp->dp_start = start;
1483     }
1484     if (size != partp->dp_size) {
1485 	warnx("WARNING: adjusting size of partition to %u", (u_int)size);
1486 	partp->dp_size = size;
1487     }
1488 
1489     return (1);
1490 }
1491 
1492 /*
1493  * Try figuring out the root device's canonical disk name.
1494  * The following choices are considered:
1495  *   /dev/ad0s1a     => /dev/ad0
1496  *   /dev/da0a       => /dev/da0
1497  *   /dev/vinum/root => /dev/vinum/root
1498  * A ".eli" part is removed if it exists (see geli(8)).
1499  * A ".journal" ending is removed if it exists (see gjournal(8)).
1500  */
1501 static char *
1502 get_rootdisk(void)
1503 {
1504 	struct statfs rootfs;
1505 	regex_t re;
1506 #define NMATCHES 2
1507 	regmatch_t rm[NMATCHES];
1508 	char dev[PATH_MAX], *s;
1509 	int rv;
1510 
1511 	if (statfs("/", &rootfs) == -1)
1512 		err(1, "statfs(\"/\")");
1513 
1514 	if ((rv = regcomp(&re, "^(/dev/[a-z/]+[0-9]*)([sp][0-9]+)?[a-h]?(\\.journal)?$",
1515 		    REG_EXTENDED)) != 0)
1516 		errx(1, "regcomp() failed (%d)", rv);
1517 	strlcpy(dev, rootfs.f_mntfromname, sizeof (dev));
1518 	if ((s = strstr(dev, ".eli")) != NULL)
1519 	    memmove(s, s+4, strlen(s + 4) + 1);
1520 
1521 	if ((rv = regexec(&re, dev, NMATCHES, rm, 0)) != 0)
1522 		errx(1,
1523 "mounted root fs resource doesn't match expectations (regexec returned %d)",
1524 		    rv);
1525 	if ((s = malloc(rm[1].rm_eo - rm[1].rm_so + 1)) == NULL)
1526 		errx(1, "out of memory");
1527 	memcpy(s, rootfs.f_mntfromname + rm[1].rm_so,
1528 	    rm[1].rm_eo - rm[1].rm_so);
1529 	s[rm[1].rm_eo - rm[1].rm_so] = 0;
1530 
1531 	return s;
1532 }
1533