#include <stdio.h>
#include <errno.h>
#include <limits.h>
#include <sys/select.h>

#include <inotify.h>

#define BUF_LEN (10 * (sizeof(struct inotify_event) + NAME_MAX + 1))

int
main (int arg, char * argv [])
{
	int    notify_d,
	       watch_id;
	fd_set rfds;
	int    sel_ret;

	FD_ZERO (&rfds);

	notify_d = inotify_init ();
	if (notify_d == -1)
	{
		perror ("could not init inotify");
		return 1;
	}

	FD_SET  (notify_d, &rfds);

	watch_id = inotify_add_watch (notify_d, argv[1], 
	                              IN_CREATE|IN_OPEN|IN_MODIFY|IN_CLOSE);
	if (watch_id == -1)
	{
		perror ("could not add watch");
		return 2;
	}

	while (sel_ret = select (notify_d+1, &rfds, NULL, NULL, NULL)) 
	{
		ssize_t numRead;
		char buf[BUF_LEN] __attribute__ ((aligned(8)));
		char * p;
		struct inotify_event *event;
		char * ev_name = NULL;

		numRead = read(notify_d, buf, BUF_LEN);

		if (numRead == 0)
		{
			perror("read() from inotify fd returned 0!");
			return 3;
		}

		if (numRead == -1)
		{
			perror("read");
			return 3;
		}

		for (p = buf; p < buf + numRead; )
		{
			event = (struct inotify_event *) p;
			printf ("Watch Descriptor: %d\n", event->wd);
			switch (event->mask)
			{
				case IN_ACCESS:
					ev_name = "IN_ACCESS"; break;
				case IN_ATTRIB:
					ev_name = "IN_ATTRIB"; break;
				case IN_CLOSE_WRITE:
					ev_name = "IN_CLOSE_WRITE"; break;
				case IN_CLOSE_NOWRITE:
					ev_name = "IN_CLOSE_NOWRITE"; break;
				case IN_CREATE:
					ev_name = "IN_CREATE"; break;
				case IN_DELETE:
					ev_name = "IN_DELETE"; break;
				case IN_DELETE_SELF:
					ev_name = "IN_DELETE_SELF"; break;
				case IN_MODIFY:
					ev_name = "IN_MODIFY"; break;
				case IN_MOVE_SELF:
					ev_name = "IN_MOVE_SELF"; break;
				case IN_MOVED_FROM:
					ev_name = "IN_MOVED_FROM"; break;
				case IN_MOVED_TO:
					ev_name = "IN_MOVED_TO"; break;
				case IN_OPEN:
					ev_name = "IN_OPEN"; break;
			}
			printf ("Mask of Events:   %s(%d)\n", ev_name, event->mask);
			printf ("Events Cookie:    %u\n", event->cookie);
			printf ("Length of name:   %u\n", event->len);
			printf ("Event Name:       %s\n", event->name);

			p += sizeof(struct inotify_event) + event->len;
		}

		puts ("---");

		FD_SET  (notify_d, &rfds);
	}

	return 0;
}