// /file SendmailIntegrate.cpp
//
// Copyright (C) 2011, ARM Research Labs, LLC.
// See www.armresearch.com for the copyright terms.
//
// This file contains the functions for SendmailIntegrate.
//
// $Id$
//
///////////////////////////////////////////////////////////////////////////////////////////////////

#include <cstdlib>
#include <cerrno>
#include <cstring>

#include <iostream>
#include <exception>
#include <stdexcept>
#include <sstream>
#include <fstream>

#include "SendmailIntegrate.hpp"

//////////////////////////////////////////////////////////////////////////////////////////////////////////
// Configuration. ////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////

const std::string SnfMilterSendmailMcSearchString("Added by SNFMilterConfig");

const std::string SnfMilterSendmailMcIntegrationString("INPUT_MAIL_FILTER(`SNFMilter', `S=unix:/var/snf-milter/socket')dnl # Added by SNFMilterConfig");

const std::string MtaIsRunningCommand("ps axl | grep -v grep | grep -q ' sendmail: '");

//////////////////////////////////////////////////////////////////////////////////////////////////////////
// End of configuration. /////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////

void
SendmailIntegrate::SetOperatingSystem(std::string OperatingSystemType) {

    if ("OpenBSD" == OperatingSystemType) {

	IntegrationIsSupported = false;

    } else if ("FreeBSD" == OperatingSystemType) {

	IntegrationIsSupported = false;

    } else if ("Ubuntu" == OperatingSystemType) {

	IntegrationIsSupported = true;
	SendmailSendmailMcPath = "/etc/mail/sendmail.mc";
	SendmailSendmailCfPath = "/etc/mail/sendmail.cf";
	BuildInstallSendmailCfFile = "(cd /etc/mail && make)";
	ReloadMtaCommand = "/etc/init.d/sendmail reload";

	FileToBackup.push_back(SendmailSendmailMcPath);
	FileToBackup.push_back(SendmailSendmailCfPath);

    } else if ("RedHat" == OperatingSystemType) {

	IntegrationIsSupported = true;
	SendmailSendmailMcPath = "/etc/mail/sendmail.mc";
	SendmailSendmailCfPath = "/etc/mail/sendmail.cf";
	BuildInstallSendmailCfFile = "(cd /etc/mail && make)";
	ReloadMtaCommand = "/etc/init.d/sendmail reload";

	FileToBackup.push_back(SendmailSendmailMcPath);
	FileToBackup.push_back(SendmailSendmailCfPath);

    } else if ("Suse" == OperatingSystemType) {

	IntegrationIsSupported = true;
	SendmailSendmailMcPath = "/etc/mail/linux.mc";
	SendmailSendmailCfPath = "/etc/mail/sendmail.cf";
	BuildInstallSendmailCfFile = "(cd /etc/mail && rm -f sendmail.cf && m4 /etc/mail/linux.mc > sendmail.cf)";
	ReloadMtaCommand = "/etc/init.d/sendmail reload";

	FileToBackup.push_back(SendmailSendmailMcPath);
	FileToBackup.push_back(SendmailSendmailCfPath);

    } else {

	std::ostringstream Temp;

	Temp << "***Error from SendmailIntegrate::SetOperatingSystem:  Invalid value of OperatingSystemType:  "
	     << OperatingSystemType;

	throw std::runtime_error(Temp.str());

    }

}

void
SendmailIntegrate::Integrate(FileBackup *SaveFile) {

    if (!IntegrationIsSupported) {

	return;

    }

    if (IsIntegrated()) {

	return;

    }

    if (Verbose()) {

	std::cout << "Add to sendmail file " << SendmailSendmailMcPath << ":  '"
		  << SnfMilterSendmailMcIntegrationString << "' and generate new "
		  << SendmailSendmailCfPath << " file with the command '"
		  << BuildInstallSendmailCfFile << "'...";

    }

    if (!Explain()) {

	for (FileToBackupType::iterator iFile = FileToBackup.begin(); iFile != FileToBackup.end(); iFile++) {

	    SaveFile->CreateBackupFile(*iFile);                                 // Save any existing file.

	}

        std::ofstream Output;                                                   // Append the configuration.

	Output.open(SendmailSendmailMcPath.c_str(), std::ios::app);
	if (!Output) {
	    std::string Temp;

	    Temp = "Error opening the sendmail configuration file " + SendmailSendmailMcPath;
	    Temp += " for writing:  ";
	    Temp += strerror(errno);
	    throw std::runtime_error(Temp);
	}

	Output << SnfMilterSendmailMcIntegrationString << "\n";
	if (!Output) {
	    std::string Temp;

	    Temp = "Error appending to the sendmail configuration file " + SendmailSendmailMcPath;
	    Temp += ":  ";
	    Temp += strerror(errno);
	    throw std::runtime_error(Temp);
	}

	Output.close();
	if (!Output) {
	    std::string Temp;

	    Temp = "Error closing the sendmail configuration file " + SendmailSendmailMcPath;
	    Temp += " after appending:  ";
	    Temp += strerror(errno);
	    throw std::runtime_error(Temp);

	}

	if (std::system(BuildInstallSendmailCfFile.c_str()) != 0) {

	    std::string Temp;

	    Temp = "Error generating sendmail configuration file " + SendmailSendmailCfPath;
	    throw std::runtime_error(Temp);

	}

    }

    OutputVerboseEnd();

    if (!ReloadMta()) {

        std::cerr << "Unable to reload the sendmail configuration.  Please reload "
		  << " the sendmail configuration for the integration with SNFMilter to take effect.";

    }

}

void
SendmailIntegrate::Unintegrate(FileBackup *SaveFile) {

    if (!IntegrationIsSupported) {

	return;

    }

    if (!IsIntegrated()) {

	return;

    }

    std::ifstream Input;

    if (Verbose()) {

	std::cout << "Remove integration in sendmail file " << SendmailSendmailMcPath
		  << " and generate new " << SendmailSendmailCfPath << " file with the command '"
		  << BuildInstallSendmailCfFile << "'--\n";

    }

    if (!Explain()) {

	for (FileToBackupType::iterator iFile = FileToBackup.begin(); iFile != FileToBackup.end(); iFile++) {

            SaveFile->CreateBackupFile(*iFile);                                 // Save any existing file.

	}

        Input.open(SendmailSendmailMcPath.c_str());                             // Read the contents.
	if (!Input) {
	    std::string Temp;

	    Temp = "Error opening the sendmail configuration file " + SendmailSendmailMcPath;
	    Temp += " for reading:  ";
	    Temp += strerror(errno);
	    throw std::runtime_error(Temp);
	}

	std::string Content;
	std::string Line;

	while (getline(Input, Line)) {

            if (std::string::npos != Line.find(SnfMilterSendmailMcSearchString)) { // Check for integration line.

		if (Verbose()) {

		    std::cout << "  Remove '" << Line << "'...\n";

		}
		continue;                                                           // Do not copy this line.

	    }

	    Content += Line + "\n";                                                 // Copy this line.

	}

	if (!Input.eof()) {                                                         // Should be at end-of-file.
	    std::string Temp;

	    Temp = "Error reading the sendmail configuration file " + SendmailSendmailMcPath;
	    Temp += ":  ";
	    Temp += strerror(errno);
	    throw std::runtime_error(Temp);
	}

	Input.close();
	if (Input.bad()) {
	    std::string Temp;

	    Temp = "Error closing the sendmail configuration file " + SendmailSendmailMcPath;
	    Temp += " after reading:  ";
	    Temp += strerror(errno);
	    throw std::runtime_error(Temp);
	}

        std::ofstream Output;                                                   // Write the updated contents.

	Output.open(SendmailSendmailMcPath.c_str(), std::ios::trunc);
	if (!Output) {
	    std::string Temp;

	    Temp = "Error opening the sendmail configuration file " + SendmailSendmailMcPath;
	    Temp += " for writing:  ";
	    Temp += strerror(errno);
	    throw std::runtime_error(Temp);
	}

	Output << Content;
	if (!Output) {
	    std::string Temp;

	    Temp = "Error writing the sendmail configuration file " + SendmailSendmailMcPath;
	    Temp += ":  ";
	    Temp += strerror(errno);
	    throw std::runtime_error(Temp);
	}

	Output.close();
	if (!Output) {
	    std::string Temp;

	    Temp = "Error closing the sendmail configuration file " + SendmailSendmailMcPath;
	    Temp += " after writing:  ";
	    Temp += strerror(errno);
	    throw std::runtime_error(Temp);
	}

        if (std::system(BuildInstallSendmailCfFile.c_str()) != 0) {             // Rebuild and install the sendmail configuration file.

	    std::string Temp;

	    Temp = "Error generating sendmail configuration file " + SendmailSendmailCfPath;
	    throw std::runtime_error(Temp);

	}

    }

    OutputVerboseEnd();

    if (!ReloadMta()) {

        std::cerr << "Unable to reload the sendmail configuration.  Please run "
		  << "'sendmail reload' for the integration with SNFMilter to take effect.";

    }

}

bool
SendmailIntegrate::MtaIsRunningDetected() {

    if (Verbose()) {

	std::cout << "Checking whether sendmail is detected to be running...";

    }

    bool IsRunningDetected;

    IsRunningDetected = (std::system(MtaIsRunningCommand.c_str()) == 0);

    if (Verbose()) {

	std::cout << (IsRunningDetected ? "yes..." : "no...");

    }

    OutputVerboseEnd();

    return IsRunningDetected;

}

bool
SendmailIntegrate::ReloadMta() {

    if (!MtaIsRunningDetected()) {

        return true;

    }

    if (Verbose()) {

	std::cout << "Reloading sendmail with the command '"
		  << ReloadMtaCommand << "'...\n";
	std::cout.flush();

    }

    bool Succeeded;

    if (!Explain()) {

	Succeeded = (std::system(ReloadMtaCommand.c_str()) == 0);

	if (Verbose()) {

	    std::cout << (Succeeded ? "succeeded..." : "failed...");

	}

    }

    OutputVerboseEnd();

    return Succeeded;

}

bool
SendmailIntegrate::IsIntegrated() {

    if (Verbose()) {

	std::cout << "Checking for any SNFMilter integration in the sendmail file " << SendmailSendmailMcPath << "...";

    }

    if (!FileExists(SendmailSendmailMcPath)) {

	if (Verbose()) {

	    std::cout << "file doesn't exist; sendmail is not integrated...";

	}

	OutputVerboseEnd();

	return false;

    }

    bool Integrated = false;

    std::ifstream Input;

    Input.open(SendmailSendmailMcPath.c_str());                                      // Read the contents.
    if (!Input) {
	std::string Temp;

	Temp = "Error opening the sendmail configuration file " + SendmailSendmailMcPath;
	Temp += " for reading:  ";
	Temp += strerror(errno);
	throw std::runtime_error(Temp);
    }

    std::string Line;

    while (getline(Input, Line)) {

        if (std::string::npos != Line.find(SnfMilterSendmailMcSearchString)) {  // Check for integration line.

	    Integrated = true;                                                  // Found it.

	    break;

	}

    }

    Input.close();
    if (Input.bad()) {
	std::string Temp;

	Temp = "Error closing the sendmail configuration file " + SendmailSendmailMcPath;
	Temp += " after reading:  ";
	Temp += strerror(errno);
	throw std::runtime_error(Temp);
    }

    if (Verbose()) {

	if (Integrated) {

	    std::cout << "found '" << Line << "'...";

	} else {

	    std::cout << "none found...";

	}

    }

    OutputVerboseEnd();

    return Integrated;

}