path: root/sbin/newfs_msdos/newfs_msdos.c

/*	$OpenBSD: newfs_msdos.c,v 1.4 1997/01/15 23:41:32 millert Exp $ */

/*
 * Copyright (c) 1995, 1996 Joerg Wunsch
 *
 * All rights reserved.
 *
 * This program is free software.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Create an MS-DOS (FAT) file system.
 *
 * from: FreeBSD Id: mkdosfs.c,v 1.2 1996/01/30 02:35:08 joerg Exp 
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <memory.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <util.h>

#include "bootcode.h"
#include "dosfs.h"

struct descrip {
	/* our database key */
	u_int32_t	kilobytes;

	/* MSDOS 3.3 BPB fields */
	u_int16_t	sectsiz;
	u_int8_t	clustsiz;
	u_int16_t	ressecs;
	u_int8_t	fatcnt;
	u_int16_t	rootsiz;
	u_int16_t	totsecs;
	u_int8_t	media;
	u_int16_t	fatsize;
	u_int16_t	trksecs;
	u_int16_t	headcnt;
	u_int16_t	hidnsec;

	/* MSDOS 4 BPB extensions */
	u_int32_t	ext_totsecs;
	u_int16_t	ext_physdrv;
	u_int8_t	ext_extboot;
	int8_t		ext_label[11];
	int8_t		ext_fsysid[8];
};

static struct descrip table[] = {
	/* NB: must be sorted, starting with the largest format! */
	/*
	 * kilobytes
	 * sec cls res fat  rot   tot   med fsz spt hds hid
	 * tot phs ebt    label	  fsysid
	 */
	{1440, 512, 1, 1, 2, 224, 2880, 0xf0, 9, 18, 2, 0,
		0, 0, 0, "4.4BSD     ", "FAT12   "},
	{1200, 512, 1, 1, 2, 224, 2400, 0xf9, 7, 15, 2, 0,
		0, 0, 0, "4.4BSD     ", "FAT12   "},
	{720,  512, 2, 1, 2, 112, 1440, 0xf9, 3, 9, 2, 0,
		0, 0, 0, "4.4BSD     ", "FAT12   "},
	{360,  512, 2, 1, 2, 112, 720, 0xfd, 2, 9, 2, 0,
		0, 0, 0, "4.4BSD     ", "FAT12   "},
};

void
usage(void)
{
	fprintf(stderr, "usage: ");
	errx(2, "[-s kbytes] [-L label] device");
}

unsigned
findformat(fd)
	int fd;
{
	struct stat sb;

	/*
	 * This is a bit tricky.  If the argument is a regular file, we can
	 * lseek() to its end and get the size reported.  If it's a device
	 * however, lseeking doesn't report us any useful number.  Instead,
	 * we try to seek just to the end of the device and try reading a
	 * block there.  In the case where we've hit exactly the device
	 * boundary, we get a zero read, and thus have found the size.
	 * Since our knowledge of distinct formats is limited anyway, this
	 * is not a big deal at all.
	 */

	if (fstat(fd, &sb) == -1)
		err(1, "Huh? Cannot fstat()");	/* Cannot happen */
	if (S_ISREG(sb.st_mode)) {
		off_t   o;
		if (lseek(fd, (off_t) 0, SEEK_END) == -1 ||
		    (o = lseek(fd, (off_t) 0, SEEK_CUR)) == -1)
			/* Hmm, hmm.  Hard luck. */
			return 0;
		return (int) (o / 1024);
	} else if (S_ISCHR(sb.st_mode) || S_ISBLK(sb.st_mode)) {
		char    b[512];
		int     i, rv;
		struct descrip *dp;

		for (i = 0, dp = table;
		    i < sizeof table / sizeof(struct descrip);
		    i++, dp++) {
			if (lseek(fd, (off_t) (dp->kilobytes * 1024),
			    SEEK_SET) == 1)
				/* Uh-oh, lseek() is not supposed to
				 * fail. */
				return 0;
			if ((rv = read(fd, b, 512)) == 0)
				break;
			/* XXX The ENOSPC is for the bogus fd(4)
			 * driver return value. */
			if (rv == -1 && errno != EINVAL && errno != ENOSPC)
				return 0;
			/* else: continue */
		}
		if (i == sizeof table / sizeof(struct descrip))
			return 0;
		(void) lseek(fd, (off_t) 0, SEEK_SET);
		return dp->kilobytes;
	}
	return 0;
}


void
setup_boot_sector_from_template(bs, dp)
	union bootsector *bs;
	struct descrip *dp;
{
	memcpy((void *)bs->raw, (void *)bootcode, 512);

	/* historical part of BPB */
	s_to_little_s(bs->bsec.sectsiz, dp->sectsiz);
	bs->bsec.clustsiz = dp->clustsiz;
	s_to_little_s(bs->bsec.ressecs, dp->ressecs);
	bs->bsec.fatcnt = dp->fatcnt;
	s_to_little_s(bs->bsec.rootsiz, dp->rootsiz);
	s_to_little_s(bs->bsec.totsecs, dp->totsecs);
	bs->bsec.media = dp->media;
	s_to_little_s(bs->bsec.fatsize, dp->fatsize);
	s_to_little_s(bs->bsec.trksecs, dp->trksecs);
	s_to_little_s(bs->bsec.headcnt, dp->headcnt);
	s_to_little_s(bs->bsec.hidnsec, dp->hidnsec);

	/* MSDOS 4 extensions */
	l_to_little_l(bs->bsec.variable_part.extended.totsecs, dp->ext_totsecs);
	s_to_little_s(bs->bsec.variable_part.extended.physdrv, dp->ext_physdrv);
	bs->bsec.variable_part.extended.extboot = dp->ext_extboot;

	/* assign a "serial number" :) */
	srandom((unsigned) time((time_t) 0));
	l_to_little_l(bs->bsec.variable_part.extended.serial, random());

	memcpy((void *) bs->bsec.variable_part.extended.label,
	    (void *) dp->ext_label, 11);
	memcpy((void *) bs->bsec.variable_part.extended.fsysid,
	    (void *) dp->ext_fsysid, 8);
}
#define roundup(dst, limit) dst = (((dst) | ((limit) - 1)) & ~(limit)) + 1

int
main(argc, argv)
	int argc;
	char *argv[];
{
	union bootsector bs;
	struct descrip *dp;
	struct fat *fat;
	struct direntry *rootdir;
	const char *label = 0;
	struct tm *tp;
	time_t  now;
	int	c, i, fd, format = 0, rootdirsize;
	char *rdev;

	while ((c = getopt(argc, argv, "s:L:t:")) != -1)
		switch (c) {
		case 's':
			format = atoi(optarg);
			break;
		case 'L':
			label = optarg;
			break;
		case 't':	/* compat with "-t fstype" in newfs */
			break;
		case '?':
		default:
			usage();
		}
	argc -= optind;
	argv += optind;

	if (argc != 1)
		usage();

#if 0
	if ((fd = open(argv[0], O_RDWR | O_EXCL, 0)) == -1)
		err(1, "open(%s)", argv[0]);
#else
	if ((fd = opendev(argv[0], O_RDWR | O_EXCL, OPENDEV_PART, &rdev)) < 0)
		err(1, "%s", rdev);
#endif

	if (format == 0) {
		/*
		 * No format specified, try to figure it out.
		 */
		if ((format = findformat(fd)) == 0)
			errx(1, "cannot determine size, must use -s format");
	}
	for (i = 0, dp = table; i < sizeof table / sizeof(struct descrip); i++, dp++)
		if (dp->kilobytes == format)
			break;
	if (i == sizeof table / sizeof(struct descrip))
		errx(1, "cannot find format description for %d KB", format);

	/* prepare and write the boot sector */
	setup_boot_sector_from_template(&bs, dp);

	/* if we've got an explicit label, use it */
	if (label)
		strncpy(bs.bsec.variable_part.extended.label, label, 11);

	if (write(fd, (char *) bs.raw, sizeof bs) != sizeof bs)
		err(1, "boot sector write()");

	/* now, go on with the FATs */
	if ((fat = (struct fat *) malloc(dp->sectsiz * dp->fatsize)) == 0)
		abort();
	memset((void *) fat, 0, dp->sectsiz * dp->fatsize);

	fat->media = dp->media;
	fat->padded = 0xff;
	fat->contents[0] = 0xff;
	if (dp->totsecs > 20740 || (dp->totsecs == 0 && dp->ext_totsecs > 20740))
		/* 16-bit FAT */
		fat->contents[1] = 0xff;

	for (i = 0; i < dp->fatcnt; i++)
		if (write(fd, (char *) fat, dp->sectsiz * dp->fatsize)
		    != dp->sectsiz * dp->fatsize)
			err(1, "FAT write()");

	free((void *) fat);

	/* finally, build the root dir */
	rootdirsize = dp->rootsiz * sizeof(struct direntry);
	roundup(rootdirsize, dp->clustsiz * dp->sectsiz);

	if ((rootdir = (struct direntry *) malloc(rootdirsize)) == 0)
		abort();
	memset((void *) fat, 0, rootdirsize);

	/* set up a volume label inside the root dir :) */
	if (label)
		strncpy(rootdir[0].name, label, 11);
	else
		memcpy(rootdir[0].name, dp->ext_label, 11);
	rootdir[0].attr = FA_VOLLABEL;
	now = time((time_t) 0);
	tp = localtime(&now);
	rootdir[0].fdate.time[0] = tp->tm_sec / 2;
	rootdir[0].fdate.time[0] |= (tp->tm_min & 7) << 5;
	rootdir[0].fdate.time[1] = ((tp->tm_min >> 3) & 7);
	rootdir[0].fdate.time[1] |= tp->tm_hour << 3;
	rootdir[0].fdate.date[0] = tp->tm_mday;
	rootdir[0].fdate.date[0] |= ((tp->tm_mon + 1) & 7) << 5;
	rootdir[0].fdate.date[1] = ((tp->tm_mon + 1) >> 3) & 1;
	rootdir[0].fdate.date[1] |= (tp->tm_year - 80) << 1;

	if (write(fd, (char *) rootdir, rootdirsize) != rootdirsize)
		err(1, "root dir write()");

	(void) close(fd);
	return 0;
}