freebsd-dev/sys/i386/boot/netboot/makerom.c
1998-02-15 21:38:19 +00:00

54 lines
1.1 KiB
C

/************************************************************************
Program to put ROM checksum in ROM image.
This program strips off the FreeBSD a.out header!
************************************************************************/
#include <stdio.h>
#include <sys/fcntl.h>
unsigned char rom[ROMSIZE];
unsigned int sum;
main(argc,argv)
int argc; char *argv[];
{
int i, fd;
if (argc < 1) {
fprintf(stderr,"usage: %s rom-file\n",argv[0]);
exit(2);
}
if ((fd = open(argv[1], O_RDWR)) < 0) {
perror("unable to open file");
exit(2);
}
bzero(rom, ROMSIZE);
if (lseek(fd, (off_t)32, SEEK_SET) < 0) {
perror("lseek error");
exit(2);
}
if (read(fd, rom, ROMSIZE) < 0) {
perror("read error");
exit(2);
}
rom[5] = 0;
for (i=0,sum=0; i<ROMSIZE; i++)
sum += rom[i];
rom[5] = -sum;
for (i=0,sum=0; i<ROMSIZE; i++)
sum += rom[i];
if (sum & 0x00FF)
printf("checksum fails.\n");
if (lseek(fd, (off_t)0, SEEK_SET) < 0) {
perror("unable to seek");
exit(2);
}
if (write(fd, rom, ROMSIZE) < 0) {
perror("unable to write");
exit(2);
}
close(fd);
exit(0);
}