part.c

一款类linux的操作系统源码

/* 
 *  Roadrunner/pk
 *    Copyright (C) 1989-2001  Cornfed Systems, Inc.
 *
 *  The Roadrunner/pk operating system is free software; you can
 *  redistribute and/or modify it under the terms of the GNU General
 *  Public License, version 2, as published by the Free Software
 *  Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public
 *  License along with this program; if not, write to the Free
 *  Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA 02111-1307 USA
 *
 *  More information about the Roadrunner/pk operating system of
 *  which this file is a part is available on the World-Wide Web
 *  at: http://www.cornfed.com.
 *
 */

#include <string.h>
#include <sys.h>
#include <sys/part.h>

void
read_parttab(char *mbr, part_t parttab)
{
    part_t p;
    u_int partent;
    char *soff, *eoff;
    int i;

    bzero(parttab, PARTS * sizeof(struct part));

    for (i = 0, p = parttab, partent = PART_ENT_1;
	 i < PARTS; i++, p++, partent += PART_ENT_SIZE) {
	p->active = (u_char) loadbyte(mbr + partent + PART_OFF_BOOT);
	p->sys = (u_char) loadbyte(mbr + partent + PART_OFF_SYS);
	soff = mbr + partent + PART_OFF_START;
	eoff = mbr + partent + PART_OFF_END;
	p->st = (u_int) loadbyte(soff + 2) |
	    (((u_int) loadbyte(soff + 1) & 0xc0) << 2);
	p->sh = (u_int) loadbyte(soff);
	p->ss = (u_int) loadbyte(soff + 1) & 0x3f;
	p->et = (u_int) loadbyte(eoff + 2) |
	    (((u_int) loadbyte(eoff + 1) & 0xc0) << 2);
	p->eh = (u_int) loadbyte(eoff);
	p->es = (u_int) loadbyte(eoff + 1) & 0x3f;
	p->off = (u_long) loaddword(mbr + partent + PART_OFF_OFF);
	p->size = (u_long) loaddword(mbr + partent + PART_OFF_SIZE);
    }
}

void
write_parttab(part_t parttab, char *mbr)
{
    part_t p;
    u_int partent;
    int i;

    for (i = 0, p = parttab, partent = PART_ENT_1;
	 i < PARTS; i++, p++, partent += PART_ENT_SIZE) {
	storebyte((u_char) p->active, mbr + partent + PART_OFF_BOOT);
	storebyte((u_char) p->sh, mbr + partent + PART_OFF_START);
	storebyte(((u_char) ((p->st & 0x300) >> 2)) |
		  ((u_char) (p->ss & 0x3f)),
		  mbr + partent + PART_OFF_START + 1);
	storebyte((u_char) (p->st & 0xff),
		  mbr + partent + PART_OFF_START + 2);
	storebyte((u_char) p->sys, mbr + partent + PART_OFF_SYS);
	storebyte((u_char) p->eh, mbr + partent + PART_OFF_END);
	storebyte(((u_char) ((p->et & 0x300) >> 2)) |
		  ((u_char) (p->es & 0x3f)),
		  mbr + partent + PART_OFF_END + 1);
	storebyte((u_char) (p->et & 0xff), mbr + partent + PART_OFF_END + 2);
	storedword(p->off, mbr + partent + PART_OFF_OFF);
	storedword(p->size, mbr + partent + PART_OFF_SIZE);
    }
}