/*
 * Copyright (c) 2007 Hypertriton, Inc. <http://hypertriton.com/>
 * 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.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 OR CONTRIBUTORS 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.
 */

/*
 * Mail delivery monitoring daemon. This program executes round-trip tests
 * to ensure that the mail system is performing.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>

#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include <dirent.h>
#include <signal.h>
#include <syslog.h>

#include "pathnames.h"
#include "smtp.h"

#ifndef MAXPATHLEN
#define MAXPATHLEN 1024
#endif

char *smtpHost = "localhost";
char *smtpPort = "2525";
char *testSndr = "root@localhost";
char *testRcpt = "mailmond@localhost";
char *testMaildir = "/var/mailmond/Maildir/";
char *testSpamdir = "/var/mailmond/Maildir/.Spam/";
int   testIval = 30;
int   testDelayMax = 60;
int   Verbose = 0;

char *SpamSample, *HamSample;
size_t SpamSampleLen = 0;
size_t HamSampleLen = 0;

volatile int die_signal = 0;
volatile int die_flag = 0;

static int
LoadConfig(const char *path)
{
	char *data, *line, *pLine;
	size_t dataLen;
	FILE *f;

	if ((f = fopen(path, "r")) == NULL) {
		fprintf(stderr, "%s: %s\n", path, strerror(errno));
		return (-1);
	}
	fseek(f, 0, SEEK_END); dataLen = (size_t)ftell(f);
	fseek(f, 0, SEEK_SET);
	if ((data = malloc(dataLen)) == NULL) {
		fprintf(stderr, "Out of memory\n");
		return (-1);
	}
	if (fread(data, dataLen, 1, f) < 1) {
		fprintf(stderr, "Error reading config file\n");
		fclose(f);
		return (-1);
	}
	pLine = data;
	while ((line = strsep(&pLine, "\n")) != NULL) {
		char *s = line;
		char *key, *val;

		if (s[0] == '#' || s[0] == '\0') {
			continue;
		}
		key = strsep(&line, "=");
		val = strsep(&line, "=");
		if (key == NULL || val == NULL) {
			continue;
		}
		if (!strcasecmp(key,"smtp.host")) { smtpHost = val; }
		else if (!strcasecmp(key,"smtp.port")) { smtpPort = val; }
		else if (!strcasecmp(key,"test.sender")) { testSndr = val; }
		else if (!strcasecmp(key,"test.recipient")) { testRcpt = val; }
		else if (!strcasecmp(key,"test.maildir")) { testMaildir = val; }
		else if (!strcasecmp(key,"test.spamdir")) { testSpamdir = val; }
		else if (!strcasecmp(key,"test.interval")) {
			testIval = atoi(val);
		} else if (!strcasecmp(key,"test.delayMax")) {
			testDelayMax = atoi(val);
		} else {
			fprintf(stderr, "%s: No such option: %s\n", path, key);
		}
	}
	fclose(f);

	printf("SMTP host = %s:%s\n", smtpHost, smtpPort);
	printf("Test sender = %s\n", testSndr);
	printf("Test recipient = %s\n", testRcpt);
	printf("Test maildir = %s\n", testMaildir);
	printf("Test spamdir = %s\n", testSpamdir);
	printf("Test interval = %d\n", testIval);
	printf("Test maximum delay = %d\n", testDelayMax);
	return (0);
}

static int
LoadSamples(void)
{
	FILE *f;

	if ((f = fopen("spam1.txt", "r")) == NULL) {
		fprintf(stderr, "spam1.txt: %s\n", strerror(errno));
		return (-1);
	}
	fseek(f, 0, SEEK_END); SpamSampleLen = (size_t)ftell(f);
	fseek(f, 0, SEEK_SET);
	if ((SpamSample = malloc(SpamSampleLen)) == NULL) {
		fprintf(stderr, "Out of memory\n");
		fclose(f);
		return (-1);
	}
	if (fread(SpamSample, SpamSampleLen, 1, f) < 1) {
		fprintf(stderr, "Error reading spam sample\n");
		fclose(f);
		return (-1);
	}
	fclose(f);
	
	if ((f = fopen("nonspam1.txt", "r")) == NULL) {
		fprintf(stderr, "nonspam1.txt: %s\n", strerror(errno));
		return (-1);
	}
	fseek(f, 0, SEEK_END); HamSampleLen = (size_t)ftell(f);
	fseek(f, 0, SEEK_SET);
	if ((HamSample = malloc(HamSampleLen)) == NULL) {
		fprintf(stderr, "Out of memory\n");
		fclose(f);
		return (-1);
	}
	if (fread(HamSample, HamSampleLen, 1, f) < 1) {
		fprintf(stderr, "Error reading spam sample\n");
		fclose(f);
		return (-1);
	}
	fclose(f);
	return (0);
}

static void
Alarm(void)
{
	syslog(LOG_ERR, "Mail system failure");
	printf("FAILURE\n");

#if 0
	printf("Stopping Postfix\n");
	system("/usr/bin/sudo /usr/local/sbin/postfix.stop");
	sleep(5);
	printf("Stopping mailprocd\n");
	system("/usr/bin/sudo /usr/local/sbin/mailprocd.stop");
	sleep(30);
	printf("Starting mailprocd\n");
	system("/usr/bin/sudo /usr/local/sbin/mailprocd.run");
	sleep(15);
	printf("Starting postfix\n");
	system("/usr/bin/sudo /usr/local/sbin/postfix.run");
#endif
}

static int
CheckMaildir(const char *maildir)
{
	char path[MAXPATHLEN];
	struct dirent *dent;
	DIR *dir;
	int nMsgs = 0;

	strlcpy(path, maildir, sizeof(path));
	strlcat(path, "new", sizeof(path));
	if ((dir = opendir(path)) == NULL) {
		fprintf(stderr, "%s: %s\n", path, strerror(errno));
		return (-1);
	}
	while ((dent = readdir(dir)) != NULL) {
		if (dent->d_name[0] == '.') {
			continue;
		}
		strlcpy(path, maildir, sizeof(path));
		strlcat(path, "new/", sizeof(path));
		strlcat(path, dent->d_name, sizeof(path));
		if (unlink(path) == -1) {
			fprintf(stderr, "rm %s: %s\n", path, strerror(errno));
		}
		nMsgs++;
	}
	closedir(dir);
	return (nMsgs > 0) ? 0 : -1;
}

static void
sig_die(int sigraised)
{
	die_signal = sigraised;
	die_flag = 1;
}

int
main(int argc, char *argv[])
{
	struct sigaction sa;
	extern char *__progname;
	const char *cfgPath = _PATH_MAILMOND_CONF;
	int c;

	while ((c = getopt(argc, argv, "Vc:?")) != -1) {
		switch (c) {
		case 'V':
			Verbose = 1;
			break;
		case 'c':
			cfgPath = optarg;
			break;
		default:
			printf("Usage: %s [-V] [-c cfg-file]\n", __progname);
			break;
		}
	}

	if (LoadConfig(cfgPath) == -1 ||
	    LoadSamples() == -1)
		exit(1);

	sigemptyset(&sa.sa_mask);
	sa.sa_flags = 0;
	sa.sa_handler = SIG_IGN;
	sigaction(SIGCHLD, &sa, NULL);
	sigaction(SIGHUP, &sa, NULL);
	sigaction(SIGUSR1, &sa, NULL);
	sigaction(SIGPIPE, &sa, NULL);

	sigfillset(&sa.sa_mask);
	sa.sa_flags = SA_RESTART;
	sa.sa_handler = sig_die;
	sigaction(SIGINT, &sa, NULL);
	sigaction(SIGQUIT, &sa, NULL);
	sigaction(SIGTERM, &sa, NULL);

	for (;;) {
		if (Verbose) {
			printf("[%s:%s] Test\n", smtpHost, smtpPort);
		}
		if (SMTP_Inject(SpamSample, SpamSampleLen, testSndr, testRcpt,
		    smtpHost, smtpPort) == 0 &&
		    SMTP_Inject(HamSample, HamSampleLen, testSndr, testRcpt,
		    smtpHost, smtpPort) == 0) {
			if (die_flag) { goto cleanup; }
			sleep(testDelayMax);
			if (die_flag) { goto cleanup; }
			if (CheckMaildir(testMaildir) == -1 ||
			    CheckMaildir(testSpamdir) == -1) {
				Alarm();
			}
			if (Verbose) {
				printf("[%s:%s] OK\n", smtpHost, smtpPort);
			}
		} else {
			Alarm();
		}
		if (die_flag) { goto cleanup; }
		sleep(testIval);
		if (die_flag) { goto cleanup; }
	}
cleanup:
	syslog(LOG_NOTICE, "exiting on signal %d", die_signal);
	fprintf(stderr, "Exiting on signal %d\n", die_signal);
	CheckMaildir(testMaildir);
	CheckMaildir(testSpamdir);
	return (0);
}