// Modified from https://lwn.net/Articles/533492/
// Copyright 2013, Michael Kerrisk
// Licensed under GNU General Public License v2 or later

#define _GNU_SOURCE
#include <sched.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <signal.h>
#include <stdio.h>
#include <sys/mount.h>

// A simple error-handling function: print an error message based
// on the value in 'errno' and terminate the calling process
#define errExit(msg)    do { perror(msg); exit(EXIT_FAILURE); \
} while (0)

// Function de départ pour le processus fils cloné
static int childFunc(void *arg)
{
    char **argv = arg;

    // TODO : Mise en place pour le processus fils

    execvp(argv[0], &argv[0]);
    errExit("execvp");
}

// Espace mémoire réservé pour la pile du processus fils
#define STACK_SIZE (1024 * 1024)
static char child_stack[STACK_SIZE];

int main(int argc, char *argv[])
{
    int flags = 0;
    pid_t child_pid;

    // TODO : Mise en place du flag pour le PID namespace

    child_pid = clone(childFunc, child_stack + STACK_SIZE, flags | SIGCHLD, &argv[1]);

    if (child_pid == -1)
        errExit("clone");

    printf("%s: PID of child created by clone() is %ld\n", argv[0], (long) child_pid);

    // Le processus parent continue ici

    // Attent que le processus fils se termine
    if (waitpid(child_pid, NULL, 0) == -1)
        errExit("waitpid");

    printf("%s: terminating\n", argv[0]);
    exit(EXIT_SUCCESS);
}