cp(1) copy file1 to file2

cp.c

#include <stdio.h>
#include <fcntl.h>
#include <stdarg.h>
#include <sys/syscall.h>

#define PERMS 0666
#define BUFSIZE 10000

void error(char *fmt, ...){
	va_list args;
	fprintf(stderr, fmt, args);
}

int main(int argc, char *argv[])
{
	int f1, f2, n;
	char buf[BUFSIZE];

	if(argc != 3){
		error("Usage: cp from to");
	}

	f1 = open(argv[1], PERMS);

	if(f1 == -1){
		error("cannot open %s", argv[1]);
	}

	f2 = open(argv[2], PERMS);

	if(f1 == -1){
		error("cannot open %s", argv[2]);
	}

	while((n = read(f1, buf, BUFSIZE)) > 0){
		if(write(f2, buf, n) != n){
			error("write error %s", argv[2]);
		}
	}

	return 0;
}