/*
 * inotify-watch.c
 *
 * Watch a file or directory for changes using inotify
 *
 * Copyright (c) 2008-2009 Tobias Klauser <tklauser@distanz.ch>
 *
 * All rights reserved.
 */

#define _GNU_SOURCE

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>

#include <sys/inotify.h>
#include <sys/time.h>

#define log(fmt, args...) do {			\
	struct timeval now;			\
	char buf[sizeof("XX:XX:XX")];		\
	if (gettimeofday(&now, NULL) == 0 &&	\
	    strftime(buf, sizeof(buf), "%T", localtime(&now.tv_sec)) != 0) { \
		fprintf(stdout, "%s.%06lu " fmt, buf, now.tv_usec, ##args); \
	} } while(0)
#define log_cont(fmt, args...) fprintf(stdout, fmt, ##args)
#define ARRAY_SIZE(x)	(sizeof(x) / sizeof(*x))
#define DECLARE_M2STR(x) { x, #x }

struct mask2string {
	uint32_t mask;
	const char *desc;
};

static const struct mask2string events[] = {
	DECLARE_M2STR(IN_ACCESS),
	DECLARE_M2STR(IN_MODIFY),
	DECLARE_M2STR(IN_ATTRIB),
	DECLARE_M2STR(IN_CLOSE_WRITE),
	DECLARE_M2STR(IN_CLOSE_NOWRITE),
	DECLARE_M2STR(IN_OPEN),
	DECLARE_M2STR(IN_MOVED_FROM),
	DECLARE_M2STR(IN_MOVED_TO),
	DECLARE_M2STR(IN_CREATE),
	DECLARE_M2STR(IN_DELETE),
	DECLARE_M2STR(IN_DELETE_SELF),
	DECLARE_M2STR(IN_MOVE_SELF),
	DECLARE_M2STR(IN_UNMOUNT),
	DECLARE_M2STR(IN_Q_OVERFLOW),
	DECLARE_M2STR(IN_IGNORED),
	/* special flags */
	DECLARE_M2STR(IN_ONLYDIR),
	DECLARE_M2STR(IN_DONT_FOLLOW),
	DECLARE_M2STR(IN_MASK_ADD),
	DECLARE_M2STR(IN_ONESHOT),
};

static void inotify_print_event(struct inotify_event *inev)
{
	unsigned int i;

	/* stat? */
	log("(%s) wd=%04x, cookie=%04x, len=%04x, name=\"%s\" :",
			inev->mask & IN_ISDIR ? "dir" : "file",
			inev->wd, inev->cookie, inev->len,
			inev->len > 0 ? inev->name : "");

	for (i = 0; i < ARRAY_SIZE(events); i++)
		if (inev->mask & events[i].mask)
			log_cont(" %s", events[i].desc);

	log_cont("\n");
}

int main(int argc, char *argv[])
{
	int fd, len;
	int *watches;
	struct inotify_event *inev;
	char buf[1024];

	if (argc < 2) {
		fprintf(stderr, "Usage: %s <path> ...\n", *argv);
		exit(EXIT_FAILURE);
	}

	++argv;

	fd = inotify_init();
	if (fd < 0) {
		perror("inotify_init");
		exit(EXIT_FAILURE);
	}

	watches = malloc((argc - 1) * sizeof(int));
	if (!watches) {
		perror("malloc");
		exit(EXIT_FAILURE);
	}

	while (*argv) {
		*watches = inotify_add_watch(fd, *argv, IN_ALL_EVENTS|IN_UNMOUNT);
		if (*watches < 0) {
			perror("inotify_add_watch");
			exit(EXIT_FAILURE);
		}
		++watches;
		++argv;
	}

	while (1) {
		len = read(fd, buf, sizeof(buf));
		inev = (struct inotify_event *) &buf;
		while (len > 0) {
			inotify_print_event(inev);

			len -= sizeof(struct inotify_event) + inev->len;
			inev = (struct inotify_event *) ((char *) inev
					+ sizeof(struct inotify_event) + inev->len);
		}
	}

	return 0;
}