#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <string.h>

#include <sys/inotify.h>

int
main()
{
	int ino, watch, len, x;
	char path[128];
	struct inotify_event *e;

	if ( (ino = inotify_init()) < 0) {
		perror(NULL);
		return 1;
	}
	sprintf(path, "/proc/self/fd/%d", ino);
	if ( (watch = inotify_add_watch(ino, path, IN_ALL_EVENTS)) < 0) {
		perror(NULL);
		return 2;
	}
	len = sizeof(struct inotify_event) + strlen(path) + 1;
	e = (struct inotify_event *)malloc(len);
	if (!e) {
		perror(NULL);
		return 3;
	}
	if ( (x = fork()) < 0) {
		perror(NULL);
		return 4;
	} else if (x == 0) { /* child */
		chmod(path, 0);
		_Exit(0);
	} else { /* parent */
		int status;
		ssize_t s;

		wait(&status);
	retry:
		s = read(ino, e, len);
		if (s < 0) {
			perror(NULL);
			_Exit(4);
		}
		printf("%d\n", x);
		goto retry;
	}
	free(e);
	return 0;
}