#define _GNU_SOURCE
#include <time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <signal.h>
#include <stdio.h>

int main(void)
{
	pid_t pid;
	int status;
	size_t i, count;
	unsigned long max = 300000, first;
	struct timespec ts = { .tv_nsec = 1 };
	char* const argv[] = {"/bin/tail", "-a", NULL};

	for (i = 0; i < 42000; ++i) {
		for (count = first = 0, ts.tv_nsec = 1;
		     ts.tv_nsec < max && count < 10;
		     ts.tv_nsec += 1) {
			if ((pid = fork())) {
				if (pid < 0)
					continue;
				nanosleep(&ts, NULL);
				kill(pid, SIGKILL);
				if (waitpid(pid, &status, 0) != pid)
					continue;
				if (WIFSIGNALED(status) &&
				    WTERMSIG(status) == 9) {
					continue;
				} else if (WIFEXITED(status) &&
					   WEXITSTATUS(status) == 1) {
					count++;
					if (!first)
						first = ts.tv_nsec;
				} else
					printf("%lu: %x\n", ts.tv_nsec, status);
			} else {
				close(STDOUT_FILENO);
				close(STDERR_FILENO);
				execve("/bin/tail", argv, NULL);
				_exit(2);
			}
		}
		if (max < ts.tv_nsec)
			max = ts.tv_nsec;
		if (count < 10)
			max += 5000;
		printf("break at %lu (max: %lu) count %lu (first at %lu)\n",
		       ts.tv_nsec, max, count, first);
	}

	return 0;
}