/*
 * Copyright (C) 2008,2009 Sebastian Krahmer.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Sebastian Krahmer.
 * 4. The name Sebastian Krahmer may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/* inotify.cc simply watches files/dirs on Linux 2.6+ Kernels.
 * call like "inotify /tmp /var/ ..."
 */
#include <stdio.h>
#include <stdlib.h>
#include <sys/inotify.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>

#include <string>
#include <vector>
#include <map>

using namespace std;

struct mask2string {
	u_int32_t mask;
	const char *desc;
};

struct mask2string events[] = {
	{IN_ACCESS, "accessed"},
	{IN_ATTRIB, "attributes changed"},
	{IN_CLOSE_WRITE, "writable closed"},
	{IN_CLOSE_NOWRITE, "non-writable closed"},
	{IN_CREATE, "created"},
	{IN_DELETE, "deleted"},
	{IN_DELETE_SELF, "(self) deleted"},
	{IN_MODIFY, "modified"},
	{IN_MOVE_SELF, "(self) moved"},
	{IN_MOVED_FROM, "moved out of dir"},
	{IN_MOVED_TO, "moved into dir"},
	{IN_OPEN, "opened"},
	{-1, NULL}
};


namespace global {
	map<u_int32_t, string> wd2path;
	bool recurse = 0;
	int ifd = -1;
}

using namespace global;

void print_status(struct inotify_event *ie)
{
	struct stat st;
	int i = 0;
	string path = wd2path[(u_int32_t)ie->wd];

	if (ie->len) {
		path += "/";
		path += string(ie->name);
	}
	printf("[%s] ", path.c_str());
	if (stat(path.c_str(), &st) == 0) {
		printf("[ino:%08zd] [mode:%05o] [uid:%04d] [gid:%04d] [size:%08zd] ", 
		       st.st_ino, st.st_mode, st.st_uid, st.st_gid, st.st_size);
	} else {
		printf("[no stat(2) possible] ");
	}

	if (recurse && (ie->mask & IN_CREATE) && S_ISDIR(st.st_mode)) {
		int wfd = inotify_add_watch(ifd, path.c_str(), IN_ALL_EVENTS);
		if (wfd >= 0)
			wd2path[wfd] = path;
	}
	
	for (i = 0; events[i].desc != NULL; ++i) {
		if (ie->mask & events[i].mask) {
			printf("%s ", events[i].desc);
		}
	}
	printf("\n");
	return;
}


int watch_path(const vector<string> &paths)
{
	char buf[4096];
	struct inotify_event *ie = (struct inotify_event *)buf;
	u_int32_t wfd = 0;

	ifd = inotify_init();
	for (vector<string>::const_iterator j = paths.begin(); j != paths.end(); ++j) {
		wfd = inotify_add_watch(ifd, (*j).c_str(), IN_ALL_EVENTS);

		if ((int)wfd < 0) {
			perror("inotify_add_watch");
			exit(errno);
		}
	
		wd2path[wfd] = *j;
	}

	for (;;) {
		if (read(ifd, ie, sizeof(buf)) < 0) {
			perror("read");
			exit(errno);
		}
		print_status(ie);
	}
	return 0;
}



int main(int argc, char **argv)
{
	vector<string> pv;
	++argv;

	for (;*argv; ++argv) {
		if (string(*argv) == string("-r")) {
			recurse = 1;
			continue;
		}
		pv.push_back(*argv);
	}
	watch_path(pv);
	return 0;
}