Simple pipe and redirect

simple-pipe-redirect.c

#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>

int main(int argc, char *argv[], char *envp[])
{
        // goal: emulate the behavior of `ls -l | grep prog > output 2> errfile`
        int outfd;
        int errfd;
        int pipefd[2];
        if (pipe(pipefd) < 0) {
                perror("pipe");
                _exit(-1);
        }
        if (fork() == 0) {
                dup2(pipefd[1], 1);
                execlp("ls", "ls", "-l",  NULL);
        }
        close(pipefd[1]);
        if (fork() == 0) {
                outfd = open("outfile", O_CREAT|O_WRONLY|O_TRUNC, 0755);
                errfd = open("errfile", O_CREAT|O_WRONLY|O_TRUNC, 0755);
                fcntl(outfd, F_SETFD, FD_CLOEXEC)
                fcntl(errfd, F_SETFD, FD_CLOEXEC)
                dup2(pipefd[0], 0);
                dup2(outfd, 1);
                dup2(errfd, 2);
                execlp("grep", "grep", "prog", NULL);
        }
        close(pipefd[0]);
        return 0;
}