#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

enum { STD_IN = 0, STD_OUT = 1 };

int main (int argc, char* argv[])
{
    int f[2], status;
    pid_t pid;
    if (pipe(f) == -1)
    {
        exit(1);
    }
    if (!(pid = fork())) {
        close(f[0]);
        dup2(f[1],STD_OUT);
        close(f[1]);
        if (!(pid = fork())) {
            int fd = open(argv[4],O_RDONLY,0);
            if (fd == -1) {
                exit(1);
            }
            if (dup2(fd,STD_IN) == -1) {
                exit(1);
            }
            close(fd);
            execlp(argv[1], argv[1], NULL);
            exit(1);
        } else if (pid == -1) {
            exit(1);
        } else {
            wait(&status);
            if (WIFEXITED(status) && !WEXITSTATUS(status)) {
                execlp(argv[2], argv[2], NULL);
                exit(1);
            }
            close(f[1]);
            wait(&status);
            exit(0);
        }
    }
    if (!(pid = fork())) {
        close(f[1]);
        dup2(f[0],STD_IN);
        close(f[0]);
        int fd = open(argv[5],O_WRONLY|O_CREAT|O_APPEND,0660);
        if (fd == -1) {
            exit(1);
        }
        if (dup2(fd,STD_OUT) == -1) {
            exit(1);
        }
        close(fd);
        execlp(argv[3], argv[3], NULL);
        exit(1);
    } else if (pid == -1) {
        exit(1);
    } else {
        close(f[0]);
        close(f[1]);
        wait(&status);
        wait(&status);
        exit(0);
    }
}