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/*
* Copyright (c) 1996 Whistle Communications
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* Whistle Communications allows free use of this software in its "as is"
* condition. Whistle Communications disclaims any liability of any kind for
* any damages whatsoever resulting from the use of this software.
*/
#ifndef lint
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include <sys/types.h>
#include <sys/disklabel.h>
#include <fcntl.h>
#include <err.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
struct mboot
{
unsigned char padding[2]; /* force the longs to be long aligned */
unsigned char bootinst[DOSPARTOFF];
struct dos_partition parts[4];
unsigned short int signature;
};
struct mboot mboot;
#define NAMEBLOCK 1 /* 2nd block */
#define BLOCKSIZE 512
#define ENABLE_MAGIC 0xfadefeed
#define DISABLE_MAGIC 0xfadefade
static int bflag;
static int eflag;
static int dflag;
#define BOOT_MAGIC 0xAA55
static void
usage(void) {
fprintf (stderr, "%s\n%s\n",
"usage: nextboot [-b] device bootstring [bootstring] ...",
" nextboot {-e,-d} device");
exit(1);
}
int
main (int argc, char** argv)
{
int fd = -1;
char namebuf[1024], *cp = namebuf;
int i,j;
int ch;
int part;
bflag = 0;
while ((ch = getopt(argc, argv, "bde")) != -1) {
switch(ch) {
case 'b':
bflag = 1;
break;
case 'd':
dflag = 1;
break;
case 'e':
eflag = 1;
break;
case '?':
default:
usage();
}
}
argc -= optind;
argv += optind;
if ( (dflag + eflag + bflag) > 1 ) {
usage();
}
if (dflag + eflag){
if(argc != 1 ) {
usage();
}
} else {
if (argc <2) {
usage();
}
}
if ((fd = open(argv[0], O_RDWR, 0)) < 0)
errx(1, "can't open %s", argv[0]);
argc--;
argv++;
/*******************************************
* Check that we have an MBR
*/
if (lseek(fd,0,0) == -1)
err(1, "lseek");
if (read (fd,&mboot.bootinst[0],BLOCKSIZE ) != BLOCKSIZE)
err(1, "read0");
if (mboot.signature != (unsigned short)BOOT_MAGIC)
errx(1, "no fdisk part.. not touching block 1");
/*******************************************
* And check that none of the partitions in it cover the name block;
*/
for ( part = 0; part < 4; part++) {
if( mboot.parts[part].dp_size
&& (mboot.parts[part].dp_start <= NAMEBLOCK)
&& (mboot.parts[part].dp_start
+ mboot.parts[part].dp_size > NAMEBLOCK))
errx(1,
"name sector lies within a Bios partition: aborting write");
}
/*******************************************
* Now check the name sector itself to see if it's been initialized.
*/
if (lseek(fd,NAMEBLOCK * BLOCKSIZE,0) == -1)
err(1, "lseek");
if (read(fd,namebuf,BLOCKSIZE) != BLOCKSIZE)
err(1, "read1");
/*******************************************
* check if we are just enabling or disabling
* Remember the flags are exclusive..
*/
if(!bflag) { /* don't care what's there if bflag is set */
switch(*(unsigned long *)cp)
{
case DISABLE_MAGIC:
case ENABLE_MAGIC:
break;
default:
errx(1, "namesector not initialized, use the -b flag");
}
}
/*******************************************
* If the z or r flag is set, damage or restore the magic number..
* to disable/enable the feature
*/
if(dflag) {
*(unsigned long *)cp = DISABLE_MAGIC;
} else {
*(unsigned long *)cp = ENABLE_MAGIC;
}
if ((!dflag) && (!eflag)) {
/*******************************************
* Create a new namesector in ram
*/
cp += 4;
for ( i = 0 ; i < argc ; i++ ) {
*cp++ = 'D';
*cp++ = 'N';
j = strlen(argv[i]);
strncpy(cp,argv[i],j);
cp += j;
*cp++ = 0;
}
*cp++ = 0xff;
*cp++ = 0xff;
*cp++ = 0xff;
namebuf[BLOCKSIZE-1] = 0; /* paranoid */
namebuf[BLOCKSIZE] = 0xff;
}
/*******************************************
* write it to disk.
*/
if (lseek(fd,NAMEBLOCK * BLOCKSIZE,0) == -1)
err(1, "lseek");
if(write (fd,namebuf,BLOCKSIZE ) != BLOCKSIZE)
err(1, "write");
#if 0
/*******************************************
* just to be safe/paranoid.. read it back..
* and print it..
*/
if (lseek(fd,NAMEBLOCK * BLOCKSIZE,0) == -1)
err(1, "lseek (second)");
read (fd,namebuf,512);
for (i = 0;i< 16;i++) {
for ( j = 0; j < 16; j++) {
printf("%02x ",(unsigned char )namebuf[(i*16) + j ]);
}
printf("\n");
}
#endif
exit(0);
}
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