#include <unistd.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>

int
check(int status) {
    return WIFEXITED(status) == 1 && WEXITSTATUS(status) == 0;
}

int
main(int argc, char **argv) {
    int fd[2];
    int past = -1, st;
    int *waits = calloc(argc - 1, sizeof(int));
    for (int j = 1; j < argc; ++j) {
        pipe(fd);
        if (!(waits[j - 1] = fork())) {
            if (j > 1 && j < argc - 1) {
                dup2(past, 0);
                if (close(past) == -1) {
                    for (int i = 0; i < j - 1; ++i) {
                        kill(waits[i], SIGKILL);
                    }
                    free(waits);
                    exit(1);
                }
                dup2(fd[1], 1);
                if (close(fd[1]) == -1) {
                    for (int i = 0; i < j - 1; ++i) {
                        kill(waits[i], SIGKILL);
                    }
                    free(waits);
                    exit(1);
                }
            } else if (j == 1) {
                if (j != argc - 1) {
                    dup2(fd[1], 1);
                    if (close(fd[1]) == -1) {
                        for (int i = 0; i < j - 1; ++i) {
                            kill(waits[i], SIGKILL);
                        }
                        free(waits);
                        exit(1);
                    }
                }
            } else {
                dup2(past, 0);
                if (close(past) == -1) {
                    for (int i = 0; i < j - 1; ++i) {
                        kill(waits[i], SIGKILL);
                    }
                    free(waits);
                    exit(1);
                }
            }
            execlp(argv[j], argv[j], NULL);
            for (int i = 0; i < j - 1; ++i) {
                kill(waits[i], SIGKILL);
            }
            free(waits);
            exit(1);
        } else if (waits[j - 1] == -1) {
            for (int i = 0; i < j - 1; ++i) {
                kill(waits[i], SIGKILL);
            }
            exit(1);
        }
        if (past != -1) {
            if (close(past) == -1) {
                for (int i = 0; i < j - 1; ++i) {
                    kill(waits[i], SIGKILL);
                }
                free(waits);
                exit(1);
            }
        }
        past = fd[0];
        if (close(fd[1]) == -1) {
            for (int i = 0; i < j - 1; ++i) {
                kill(waits[i], SIGKILL);
            }
            free(waits);
            exit(1);
        }
    }

    while (wait(&st) > 0){
        if(!check(st)){
            return 1;
        }
    }
    free(waits);
    return 0;
}