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