clone + namespaces test

#define _GNU_SOURCE
#include <sched.h>
#include <signal.h>
#include <errno.h>
#include <unistd.h>
#include <sys/wait.h>
#include <stdio.h>
#include <string.h>
#include <sys/syscall.h>

int main() {
    printf("Cloning...\n");
    pid_t pid = syscall(__NR_clone, SIGCHLD | CLONE_NEWPID | CLONE_NEWNET, 0, 0, 0);
    if (errno != 0) {
        printf("Cloning failed with errno %d: %s\n", errno, strerror(errno));
        return 1;
    }
    if (pid != 0) {
        // Parent:
        printf("Parent running.\n");
        waitpid(pid, 0, 0);
        printf("Test successful.\n");
        return 0;
    } else {
        // Child
        printf("Child running.\n");
        return 0;
    }
}