mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-29 01:59:02 +00:00
40 lines
782 B
C
40 lines
782 B
C
/*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License,
|
|
* version 2 as published by the Free Software Foundation.
|
|
*
|
|
* (C) John Crispin <blogic@openwrt.org>
|
|
*/
|
|
|
|
#include <sys/types.h>
|
|
#include <sys/stat.h>
|
|
#include <fcntl.h>
|
|
#include <stdio.h>
|
|
#include <stdint.h>
|
|
#include <unistd.h>
|
|
#include <errno.h>
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
uint32_t t = 0, sum = 0x55aa55aa;
|
|
int fd;
|
|
|
|
if ((argc != 2) || ((fd = open(argv[1], O_RDWR)) == -1)) {
|
|
fprintf(stderr, "Usage: %s input_file\n", *argv);
|
|
return -EINVAL;
|
|
}
|
|
|
|
lseek(fd, -4, SEEK_END);
|
|
write(fd, &t, 4);
|
|
lseek(fd, 0, SEEK_SET);
|
|
|
|
while (read(fd, &t, 4) > 0)
|
|
sum -= t;
|
|
|
|
lseek(fd, -4, SEEK_END);
|
|
write(fd, &sum, 4);
|
|
close(fd);
|
|
|
|
return 0;
|
|
}
|