slim/app.cpp

/* SLiM - Simple Login Manager
 *  Copyright (C) 1997, 1998 Per Liden
 *  Copyright (C) 2004-06 Simone Rota <sip@varlock.com>
 *  Copyright (C) 2004-06 Johannes Winkelmann <jw@tks6.net>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdint.h>
#include <cstring>
#include <cstdio>
#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>
#include <algorithm>

#include "app.h"
#include "numlock.h"
#include "util.h"

#ifdef HAVE_SHADOW
#include <shadow.h>
#endif

using namespace std;

#ifdef USE_PAM
#include <string>

int conv(int num_msg, const struct pam_message **msg,
		 struct pam_response **resp, void *appdata_ptr)
{
	*resp = (struct pam_response *) calloc(num_msg, sizeof(struct pam_response));
	Panel* panel = *static_cast<Panel**>(appdata_ptr);
	int result = PAM_SUCCESS;
	int i;

	for (i = 0; i < num_msg; i++) {
		(*resp)[i].resp = 0;
		(*resp)[i].resp_retcodei = 0;
		switch (msg[i]->msg_style) {
			case PAM_PROMPT_ECHO_ON:
				/* We assume PAM is asking for the username */
				panel->EventHandler(Panel::Get_Name);
				switch (panel->getAction()) {
					case Panel::Suspend:
					case Panel::Halt:
					case Panel::Reboot:
						(*resp)[i].resp=strdup("root");
						break;

					case Panel::Console:
					case Panel::Exit:
					case Panel::Login:
						(*resp)[i].resp=strdup(panel->GetName().c_str());
						break;
					default:
						break;
				}
				break;

			case PAM_PROMPT_ECHO_OFF:
				/* We assume PAM is asking for the password */
				switch (panel->getAction()) {
					case Panel::Console:
					case Panel::Exit:
						/* We should leave now! */
						result = PAM_CONV_ERR;
						break;

					default:
						panel->EventHandler(Panel::Get_Passwd);
						(*resp)[i].resp=strdup(panel->GetPasswd().c_str());
						break;
				}
				break;

			case PAM_ERROR_MSG:
			case PAM_TEXT_INFO:
				/* We simply write these to the log
				   TODO: Maybe we should simply ignore them */
				logStream << APPNAME << ": " << msg[i]->msg << endl;
				break;
		}
		if (result!=PAM_SUCCESS) break;
	}

	if (result != PAM_SUCCESS) {
		for (i = 0; i < num_msg; i++) {
			if ((*resp)[i].resp == 0)
				continue;
			free((*resp)[i].resp);
			(*resp)[i].resp = 0;
		}
		free(*resp);
		*resp = 0;
	}

	return result;
}
#endif

extern App* LoginApp;

int xioerror(Display *disp)
{
	LoginApp->RestartServer();
	return 0;
}

void CatchSignal(int sig)
{
	logStream << APPNAME << ": unexpected signal " << sig << endl;

	if (LoginApp->isServerStarted())
		LoginApp->StopServer();

	LoginApp->RemoveLock();
	exit(ERR_EXIT);
}

void User1Signal(int sig)
{
	signal(sig, User1Signal);
}

#ifdef USE_PAM
App::App(int argc, char** argv)
  : pam(conv, static_cast<void*>(&LoginPanel)),
#else
App::App(int argc, char** argv)
  :
#endif
	mcookiesize(32)		/* Must be divisible by 4 */
{
	int tmp;
	ServerPID = -1;
	testing = false;
	serverStarted = false;
	mcookie = string(App::mcookiesize, 'a');
	daemonmode = false;
	force_nodaemon = false;
	firstlogin = true;
	Dpy = NULL;

	/* Parse command line
	   Note: we force a option for nodaemon switch to handle "-nodaemon" */
	while ((tmp = getopt(argc, argv, "vhp:n:d?")) != EOF) {
		switch (tmp) {
		case 'p':	/* Test theme */
			testtheme = optarg;
			testing = true;
			if (testtheme == NULL) {
				logStream << "The -p option requires an argument" << endl;
				exit(ERR_EXIT);
			}
			break;
		case 'd':	/* Daemon mode */
			daemonmode = true;
			break;
		case 'n':	/* Daemon mode */
			daemonmode = false;
			force_nodaemon = true;
			break;
		case 'v':	/* Version */
			std::cout << APPNAME << " version " << VERSION << endl;
			exit(OK_EXIT);
			break;
		case '?':	/* Illegal */
			logStream << endl;
		case 'h':   /* Help */
			logStream << "usage:  " << APPNAME << " [option ...]" << endl
			<< "options:" << endl
			<< "	-d: daemon mode" << endl
			<< "	-nodaemon: no-daemon mode" << endl
			<< "	-v: show version" << endl
			<< "	-p /path/to/theme/dir: preview theme" << endl;
			exit(OK_EXIT);
			break;
		}
	}
#ifndef XNEST_DEBUG
	if (getuid() != 0 && !testing) {
		logStream << APPNAME << ": only root can run this program" << endl;
		exit(ERR_EXIT);
	}
#endif /* XNEST_DEBUG */

}

void App::Run()
{
	DisplayName = DISPLAY;

#ifdef XNEST_DEBUG
	char* p = getenv("DISPLAY");
	if (p && p[0]) {
		DisplayName = p;
		cout << "Using display name " << DisplayName << endl;
	}
#endif

	/* Read configuration and theme */
	cfg = new Cfg;
	cfg->readConf(CFGFILE);
	string themebase = "";
	string themefile = "";
	string themedir = "";
	themeName = "";
	if (testing) {
		themeName = testtheme;
	} else {
		themebase = string(THEMESDIR) + "/";
		themeName = cfg->getOption("current_theme");
		string::size_type pos;
		if ((pos = themeName.find(",")) != string::npos) {
			/* input is a set */
			themeName = findValidRandomTheme(themeName);
			if (themeName == "") {
				themeName = "default";
			}
		}
	}

#ifdef USE_PAM
	try {
		pam.start("slim");
		pam.set_item(PAM::Authenticator::TTY, DisplayName);
		pam.set_item(PAM::Authenticator::Requestor, "root");
	} catch(PAM::Exception& e) {
		logStream << APPNAME << ": " << e << endl;
		exit(ERR_EXIT);
	}
#endif

	bool loaded = false;
	while (!loaded) {
		themedir = themebase + themeName;
		themefile = themedir + THEMESFILE;
		if (!cfg->readConf(themefile)) {
			if (themeName == "default") {
				logStream << APPNAME << ": Failed to open default theme file "
					 << themefile << endl;
				exit(ERR_EXIT);
			} else {
				logStream << APPNAME << ": Invalid theme in config: "
					 << themeName << endl;
				themeName = "default";
			}
		} else {
			loaded = true;
		}
	}

	if (!testing) {
		/* Create lock file */
		LoginApp->GetLock();

		/* Start x-server */
		setenv("DISPLAY", DisplayName, 1);
		signal(SIGQUIT, CatchSignal);
		signal(SIGTERM, CatchSignal);
		signal(SIGKILL, CatchSignal);
		signal(SIGINT, CatchSignal);
		signal(SIGHUP, CatchSignal);
		signal(SIGPIPE, CatchSignal);
		signal(SIGUSR1, User1Signal);

#ifndef XNEST_DEBUG
		if (!force_nodaemon && cfg->getOption("daemon") == "yes") {
			daemonmode = true;
		}

		/* Daemonize */
		if (daemonmode) {
			if (daemon(0, 0) == -1) {
				logStream << APPNAME << ": " << strerror(errno) << endl;
				exit(ERR_EXIT);
			}
		}

		OpenLog();

		if (daemonmode)
			UpdatePid();

		CreateServerAuth();
		StartServer();
#endif

	}

	/* Open display */
	if ((Dpy = XOpenDisplay(DisplayName)) == 0) {
		logStream << APPNAME << ": could not open display '"
			 << DisplayName << "'" << endl;
		if (!testing) StopServer();
		exit(ERR_EXIT);
	}

	/* Get screen and root window */
	Scr = DefaultScreen(Dpy);
	Root = RootWindow(Dpy, Scr);

	// Intern _XROOTPMAP_ID property
	BackgroundPixmapId = XInternAtom(Dpy, "_XROOTPMAP_ID", False);

	/* for tests we use a standard window */
	if (testing) {
		Window RealRoot = RootWindow(Dpy, Scr);
		Root = XCreateSimpleWindow(Dpy, RealRoot, 0, 0, 1280, 1024, 0, 0, 0);
		XMapWindow(Dpy, Root);
		XFlush(Dpy);
	} else {
		blankScreen();
	}

	HideCursor();

	/* Create panel */
	LoginPanel = new Panel(Dpy, Scr, Root, cfg, themedir, Panel::Mode_DM);
	bool firstloop = true; /* 1st time panel is shown (for automatic username) */
	bool focuspass = cfg->getOption("focus_password")=="yes";
	bool autologin = cfg->getOption("auto_login")=="yes";

	if (firstlogin && cfg->getOption("default_user") != "") {
		LoginPanel->SetName(cfg->getOption("default_user"));
#ifdef USE_PAM
		pam.set_item(PAM::Authenticator::User, cfg->getOption("default_user").c_str());
#endif
		firstlogin = false;
		if (autologin) {
			Login();
		}
	}

	/* Set NumLock */
	string numlock = cfg->getOption("numlock");
	if (numlock == "on") {
		NumLock::setOn(Dpy);
	} else if (numlock == "off") {
		NumLock::setOff(Dpy);
	}

	/* Start looping */
	int panelclosed = 1;
	Panel::ActionType Action;

	while (1) {
		if (panelclosed) {
			/* Init root */
			setBackground(themedir);

			/* Close all clients */
			if (!testing) {
				KillAllClients(False);
				KillAllClients(True);
			}

			/* Show panel */
			LoginPanel->OpenPanel();
		}

		LoginPanel->Reset();

		if (firstloop && cfg->getOption("default_user") != "")
			LoginPanel->SetName(cfg->getOption("default_user"));

        if (firstloop)
            LoginPanel->SwitchSession();

		if (!AuthenticateUser(focuspass && firstloop)) {
			panelclosed = 0;
			firstloop = false;
			LoginPanel->ClearPanel();
			XBell(Dpy, 100);
			continue;
		}

		firstloop = false;

		Action = LoginPanel->getAction();
		/* for themes test we just quit */
		if (testing)
			Action = Panel::Exit;

		panelclosed = 1;
		LoginPanel->ClosePanel();

		switch (Action) {
			case Panel::Login:
				Login();
				break;
			case Panel::Console:
				Console();
				break;
			case Panel::Reboot:
				Reboot();
				break;
			case Panel::Halt:
				Halt();
				break;
			case Panel::Suspend:
				Suspend();
				break;
			case Panel::Exit:
				Exit();
				break;
			default:
				break;
		}
	}
}

#ifdef USE_PAM
bool App::AuthenticateUser(bool focuspass)
{
	/* Reset the username */
	try{
		if (!focuspass)
			pam.set_item(PAM::Authenticator::User, 0);
		pam.authenticate();
	} catch(PAM::Auth_Exception& e) {
		switch (LoginPanel->getAction()) {
			case Panel::Exit:
			case Panel::Console:
				return true; /* <--- This is simply fake! */
			default:
				break;
		}
		logStream << APPNAME << ": " << e << endl;
		return false;
	} catch(PAM::Exception& e) {
		logStream << APPNAME << ": " << e << endl;
		exit(ERR_EXIT);
	}
	return true;
}
#else
bool App::AuthenticateUser(bool focuspass)
{
	if (!focuspass) {
		LoginPanel->EventHandler(Panel::Get_Name);
		switch (LoginPanel->getAction()) {
			case Panel::Exit:
			case Panel::Console:
				logStream << APPNAME << ": Got a special command ("
						<< LoginPanel->GetName() << ")" << endl;
				return true; /* <--- This is simply fake! */
			default:
				break;
		}
	}
	LoginPanel->EventHandler(Panel::Get_Passwd);

	char *encrypted, *correct;
	struct passwd *pw;

	switch (LoginPanel->getAction()) {
		case Panel::Suspend:
		case Panel::Halt:
		case Panel::Reboot:
			pw = getpwnam("root");
			break;
		case Panel::Console:
		case Panel::Exit:
		case Panel::Login:
			pw = getpwnam(LoginPanel->GetName().c_str());
			break;
	}
	endpwent();
	if (pw == 0)
		return false;

#ifdef HAVE_SHADOW
	struct spwd *sp = getspnam(pw->pw_name);
	endspent();
	if (sp)
		correct = sp->sp_pwdp;
	else
#endif		/* HAVE_SHADOW */
		correct = pw->pw_passwd;

	if (correct == 0 || correct[0] == '\0')
		return true;

	encrypted = crypt(LoginPanel->GetPasswd().c_str(), correct);
	return ((encrypted && strcmp(encrypted, correct) == 0) ? true : false);
}
#endif

int App::GetServerPID()
{
	return ServerPID;
}

/* Hide the cursor */
void App::HideCursor()
{
	if (cfg->getOption("hidecursor") == "true") {
		XColor			black;
		char			cursordata[1];
		Pixmap			cursorpixmap;
		Cursor			cursor;
		cursordata[0]=0;
		cursorpixmap=XCreateBitmapFromData(Dpy,Root,cursordata,1,1);
		black.red=0;
		black.green=0;
		black.blue=0;
		cursor=XCreatePixmapCursor(Dpy,cursorpixmap,cursorpixmap,&black,&black,0,0);
		XDefineCursor(Dpy,Root,cursor);
	}
}

void App::Login()
{
	struct passwd *pw;
	pid_t pid;

#ifdef USE_PAM
	try{
		pam.open_session();
		pw = getpwnam(static_cast<const char*>(pam.get_item(PAM::Authenticator::User)));
	} catch(PAM::Cred_Exception& e) {
		/* Credentials couldn't be established */
		logStream << APPNAME << ": " << e << endl;
		return;
	} catch(PAM::Exception& e) {
		logStream << APPNAME << ": " << e << endl;
		exit(ERR_EXIT);
	}
#else
	pw = getpwnam(LoginPanel->GetName().c_str());
#endif
	endpwent();
	if (pw == 0)
		return;
	if (pw->pw_shell[0] == '\0') {
		setusershell();
		strcpy(pw->pw_shell, getusershell());
		endusershell();
	}

	/* Setup the environment */
	char* term = getenv("TERM");
	string maildir = _PATH_MAILDIR;
	maildir.append("/");
	maildir.append(pw->pw_name);
	string xauthority = pw->pw_dir;
	xauthority.append("/.Xauthority");

#ifdef USE_PAM
	/* Setup the PAM environment */
	try{
		if (term) pam.setenv("TERM", term);
		pam.setenv("HOME", pw->pw_dir);
		pam.setenv("PWD", pw->pw_dir);
		pam.setenv("SHELL", pw->pw_shell);
		pam.setenv("USER", pw->pw_name);
		pam.setenv("LOGNAME", pw->pw_name);
		pam.setenv("PATH", cfg->getOption("default_path").c_str());
		pam.setenv("DISPLAY", DisplayName);
		pam.setenv("MAIL", maildir.c_str());
		pam.setenv("XAUTHORITY", xauthority.c_str());
	} catch(PAM::Exception& e) {
		logStream << APPNAME << ": " << e << endl;
		exit(ERR_EXIT);
	}
#endif

#ifdef USE_CONSOLEKIT
	/* Setup the ConsoleKit session */
	try {
		ck.open_session(DisplayName, pw->pw_uid);
	}
	catch(Ck::Exception &e) {
		logStream << APPNAME << ": " << e << endl;
		exit(ERR_EXIT);
	}
#endif

	/* Create new process */
	pid = fork();
	if (pid == 0) {
#ifdef USE_PAM
		/* Get a copy of the environment and close the child's copy */
		/* of the PAM-handle. */
		char** child_env = pam.getenvlist();

# ifdef USE_CONSOLEKIT
		char** old_env = child_env;

		/* Grow the copy of the environment for the session cookie */
		int n;
		for (n = 0; child_env[n] != NULL ; n++);

		n++;

		child_env = static_cast<char**>(malloc(sizeof(char*)*n));
		memcpy(child_env, old_env, sizeof(char*)*n+1);
		child_env[n - 1] = StrConcat("XDG_SESSION_COOKIE=", ck.get_xdg_session_cookie());
		child_env[n] = NULL;
# endif /* USE_CONSOLEKIT */
#else

# ifdef USE_CONSOLEKIT
		const int Num_Of_Variables = 12; /* Number of env. variables + 1 */
# else
		const int Num_Of_Variables = 11; /* Number of env. variables + 1 */
# endif /* USE_CONSOLEKIT */
		char** child_env = static_cast<char**>(malloc(sizeof(char*)*Num_Of_Variables));
		int n = 0;
		if (term) child_env[n++]=StrConcat("TERM=", term);
		child_env[n++]=StrConcat("HOME=", pw->pw_dir);
		child_env[n++]=StrConcat("PWD=", pw->pw_dir);
		child_env[n++]=StrConcat("SHELL=", pw->pw_shell);
		child_env[n++]=StrConcat("USER=", pw->pw_name);
		child_env[n++]=StrConcat("LOGNAME=", pw->pw_name);
		child_env[n++]=StrConcat("PATH=", cfg->getOption("default_path").c_str());
		child_env[n++]=StrConcat("DISPLAY=", DisplayName);
		child_env[n++]=StrConcat("MAIL=", maildir.c_str());
		child_env[n++]=StrConcat("XAUTHORITY=", xauthority.c_str());
# ifdef USE_CONSOLEKIT
		child_env[n++]=StrConcat("XDG_SESSION_COOKIE=", ck.get_xdg_session_cookie());
# endif /* USE_CONSOLEKIT */
		child_env[n++]=0;

#endif

		/* Login process starts here */
		SwitchUser Su(pw, cfg, DisplayName, child_env);
		string session = LoginPanel->getSession();
		string loginCommand = cfg->getOption("login_cmd");
		replaceVariables(loginCommand, SESSION_VAR, session);
		replaceVariables(loginCommand, THEME_VAR, themeName);
		string sessStart = cfg->getOption("sessionstart_cmd");
		if (sessStart != "") {
			replaceVariables(sessStart, USER_VAR, pw->pw_name);
			system(sessStart.c_str());
		}
		Su.Login(loginCommand.c_str(), mcookie.c_str());
		_exit(OK_EXIT);
	}

#ifndef XNEST_DEBUG
	CloseLog();
#endif

	/* Wait until user is logging out (login process terminates) */
	pid_t wpid = -1;
	int status;
	while (wpid != pid) {
		wpid = wait(&status);
		if (wpid == ServerPID)
			xioerror(Dpy);	/* Server died, simulate IO error */
	}
	if (WIFEXITED(status) && WEXITSTATUS(status)) {
		LoginPanel->Message("Failed to execute login command");
		sleep(3);
	} else {
		 string sessStop = cfg->getOption("sessionstop_cmd");
		 if (sessStop != "") {
			replaceVariables(sessStop, USER_VAR, pw->pw_name);
			system(sessStop.c_str());
		}
	}

#ifdef USE_CONSOLEKIT
	try {
		ck.close_session();
	} catch(Ck::Exception &e) {
		logStream << APPNAME << ": " << e << endl;
	}
#endif

#ifdef USE_PAM
	try {
		pam.close_session();
	} catch(PAM::Exception& e) {
		logStream << APPNAME << ": " << e << endl;
	}
#endif

/* Close all clients */
	KillAllClients(False);
	KillAllClients(True);

	/* Send HUP signal to clientgroup */
	killpg(pid, SIGHUP);

	/* Send TERM signal to clientgroup, if error send KILL */
	if (killpg(pid, SIGTERM))
	killpg(pid, SIGKILL);

	HideCursor();

#ifndef XNEST_DEBUG
	/* Re-activate log file */
	OpenLog();
	RestartServer();
#endif

}

void App::Reboot()
{
#ifdef USE_PAM
	try {
		pam.end();
	} catch(PAM::Exception& e) {
		logStream << APPNAME << ": " << e << endl;
	}
#endif

	/* Write message */
	LoginPanel->Message((char*)cfg->getOption("reboot_msg").c_str());
	sleep(3);

	/* Stop server and reboot */
	StopServer();
	RemoveLock();
	system(cfg->getOption("reboot_cmd").c_str());
	exit(OK_EXIT);
}


void App::Halt()
{
#ifdef USE_PAM
	try {
		pam.end();
	} catch (PAM::Exception& e) {
		logStream << APPNAME << ": " << e << endl;
	}
#endif

	/* Write message */
	LoginPanel->Message((char*)cfg->getOption("shutdown_msg").c_str());
	sleep(3);

	/* Stop server and halt */
	StopServer();
	RemoveLock();
	system(cfg->getOption("halt_cmd").c_str());
	exit(OK_EXIT);
}

void App::Suspend()
{
	sleep(1);
	system(cfg->getOption("suspend_cmd").c_str());
}


void App::Console()
{
	int posx = 40;
	int posy = 40;
	int fontx = 9;
	int fonty = 15;
	int width = (XWidthOfScreen(ScreenOfDisplay(Dpy, Scr)) - (posx * 2)) / fontx;
	int height = (XHeightOfScreen(ScreenOfDisplay(Dpy, Scr)) - (posy * 2)) / fonty;

	/* Execute console */
	const char* cmd = cfg->getOption("console_cmd").c_str();
	char *tmp = new char[strlen(cmd) + 60];
	sprintf(tmp, cmd, width, height, posx, posy, fontx, fonty);
	system(tmp);
	delete [] tmp;
}

void App::Exit()
{
#ifdef USE_PAM
	try {
		pam.end();
	} catch(PAM::Exception& e) {
		logStream << APPNAME << ": " << e << endl;
	}
#endif

	if (testing) {
		const char* testmsg = "This is a test message :-)";
		LoginPanel->Message(testmsg);
		sleep(3);
		delete LoginPanel;
		XCloseDisplay(Dpy);
	} else {
		delete LoginPanel;
		StopServer();
		RemoveLock();
	}
	delete cfg;
	exit(OK_EXIT);
}

int CatchErrors(Display *dpy, XErrorEvent *ev)
{
	return 0;
}

void App::RestartServer()
{
#ifdef USE_PAM
	try {
		pam.end();
	} catch(PAM::Exception& e) {
		logStream << APPNAME << ": " << e << endl;
	}
#endif

	StopServer();
	RemoveLock();
	while (waitpid(-1, NULL, WNOHANG) > 0); /* Collects all dead childrens */
	Run();
}

void App::KillAllClients(Bool top)
{
	Window dummywindow;
	Window *children;
	unsigned int nchildren;
	unsigned int i;
	XWindowAttributes attr;

	XSync(Dpy, 0);
	XSetErrorHandler(CatchErrors);

	nchildren = 0;
	XQueryTree(Dpy, Root, &dummywindow, &dummywindow, &children, &nchildren);
	if (!top) {
		for (i=0; i<nchildren; i++) {
			if (XGetWindowAttributes(Dpy, children[i], &attr) && (attr.map_state == IsViewable))
				children[i] = XmuClientWindow(Dpy, children[i]);
			else
				children[i] = 0;
		}
	}

	for (i=0; i<nchildren; i++) {
		if (children[i])
			XKillClient(Dpy, children[i]);
	}
	XFree((char *)children);

	XSync(Dpy, 0);
	XSetErrorHandler(NULL);
}

int App::ServerTimeout(int timeout, char* text)
{
	int	i = 0;
	int pidfound = -1;
	static char	*lasttext;

	while (1) {
		pidfound = waitpid(ServerPID, NULL, WNOHANG);
		if (pidfound == ServerPID)
			break;
		if (timeout) {
			if (i == 0 && text != lasttext)
				logStream << endl << APPNAME << ": waiting for " << text;
			else
				logStream << ".";
		}
		if (timeout)
			sleep(1);
		if (++i > timeout)
			break;
	}

	if (i > 0)
		logStream << endl;
	lasttext = text;

	return (ServerPID != pidfound);
}


int App::WaitForServer()
{
	int	ncycles	 = 120;
	int	cycles;

	for (cycles = 0; cycles < ncycles; cycles++) {
		if ((Dpy = XOpenDisplay(DisplayName))) {
			XSetIOErrorHandler(xioerror);
			return 1;
		} else {
			if (!ServerTimeout(1, (char *) "X server to begin accepting connections"))
				break;
		}
	}

	logStream << "Giving up." << endl;

	return 0;
}

int App::StartServer()
{
	ServerPID = fork();

	int argc = 1, pos = 0, i;
	static const int MAX_XSERVER_ARGS = 256;
	static char* server[MAX_XSERVER_ARGS+2] = { NULL };
	server[0] = (char *)cfg->getOption("default_xserver").c_str();
	string argOption = cfg->getOption("xserver_arguments");
	/* Add mandatory -xauth option */
	argOption = argOption + " -auth " + cfg->getOption("authfile");
	char* args = new char[argOption.length()+2]; /* NULL plus vt */
	strcpy(args, argOption.c_str());

	serverStarted = false;

	bool hasVtSet = false;
	while (args[pos] != '\0') {
		if (args[pos] == ' ' || args[pos] == '\t') {
			*(args+pos) = '\0';
			server[argc++] = args+pos+1;
		} else if (pos == 0) {
			server[argc++] = args+pos;
		}
		++pos;

		if (argc+1 >= MAX_XSERVER_ARGS) {
			/* ignore _all_ arguments to make sure the server starts at */
			/* all */
			argc = 1;
			break;
		}
	}

	for (i = 0; i < argc; i++) {
		if (server[i][0] == 'v' && server[i][1] == 't') {
			bool ok = false;
			Cfg::string2int(server[i]+2, &ok);
			if (ok) {
				hasVtSet = true;
			}
		}
	}

	if (!hasVtSet && daemonmode) {
		server[argc++] = (char*)"vt07";
	}
	server[argc] = NULL;

	switch (ServerPID) {
	case 0:
		signal(SIGTTIN, SIG_IGN);
		signal(SIGTTOU, SIG_IGN);
		signal(SIGUSR1, SIG_IGN);
		setpgid(0,getpid());

		execvp(server[0], server);
		logStream << APPNAME << ": X server could not be started" << endl;
		exit(ERR_EXIT);
		break;

	case -1:
		break;

	default:
		errno = 0;
		if (!ServerTimeout(0, (char *)"")) {
			ServerPID = -1;
			break;
		}

		/* Wait for server to start up */
		if (WaitForServer() == 0) {
			logStream << APPNAME << ": unable to connect to X server" << endl;
			StopServer();
			ServerPID = -1;
			exit(ERR_EXIT);
		}
		break;
	}

	delete [] args;

	serverStarted = true;

	return ServerPID;
}

jmp_buf CloseEnv;
int IgnoreXIO(Display *d)
{
	logStream << APPNAME << ": connection to X server lost." << endl;
	longjmp(CloseEnv, 1);
}

void App::StopServer()
{
	signal(SIGQUIT, SIG_IGN);
	signal(SIGINT, SIG_IGN);
	signal(SIGHUP, SIG_IGN);
	signal(SIGPIPE, SIG_IGN);
	signal(SIGTERM, SIG_DFL);
	signal(SIGKILL, SIG_DFL);

	/* Catch X error */
	XSetIOErrorHandler(IgnoreXIO);
	if (!setjmp(CloseEnv) && Dpy)
		XCloseDisplay(Dpy);

	/* Send HUP to process group */
	errno = 0;
	if ((killpg(getpid(), SIGHUP) != 0) && (errno != ESRCH))
		logStream << APPNAME << ": can't send HUP to process group " << getpid() << endl;

	/* Send TERM to server */
	if (ServerPID < 0)
		return;

	errno = 0;

	if (killpg(ServerPID, SIGTERM) < 0) {
		if (errno == EPERM) {
			logStream << APPNAME << ": can't kill X server" << endl;
			exit(ERR_EXIT);
		}
		if (errno == ESRCH)
			return;
	}

	/* Wait for server to shut down */
	if (!ServerTimeout(10, (char *)"X server to shut down")) {
		logStream << endl;
		return;
	}

	logStream << endl << APPNAME <<
		":  X server slow to shut down, sending KILL signal." << endl;

	/* Send KILL to server */
	errno = 0;
	if (killpg(ServerPID, SIGKILL) < 0) {
		if (errno == ESRCH)
			return;
	}

	/* Wait for server to die */
	if (ServerTimeout(3, (char*)"server to die")) {
		logStream << endl << APPNAME << ": can't kill server" << endl;
		exit(ERR_EXIT);
	}
	logStream << endl;
}

void App::blankScreen()
{
	GC gc = XCreateGC(Dpy, Root, 0, 0);
	XSetForeground(Dpy, gc, BlackPixel(Dpy, Scr));
	XFillRectangle(Dpy, Root, gc, 0, 0,
				   XWidthOfScreen(ScreenOfDisplay(Dpy, Scr)),
				   XHeightOfScreen(ScreenOfDisplay(Dpy, Scr)));
	XFlush(Dpy);
	XFreeGC(Dpy, gc);

}

void App::setBackground(const string& themedir)
{
	string filename;
	filename = themedir + "/background.png";
	image = new Image;
	bool loaded = image->Read(filename.c_str());
	if (!loaded) { /* try jpeg if png failed */
		filename = themedir + "/background.jpg";
		loaded = image->Read(filename.c_str());
	}

	if (loaded) {
		string bgstyle = cfg->getOption("background_style");
		if (bgstyle == "stretch") {
			image->Resize(XWidthOfScreen(ScreenOfDisplay(Dpy, Scr)),
						XHeightOfScreen(ScreenOfDisplay(Dpy, Scr)));
		} else if (bgstyle == "tile") {
			image->Tile(XWidthOfScreen(ScreenOfDisplay(Dpy, Scr)),
						XHeightOfScreen(ScreenOfDisplay(Dpy, Scr)));
		} else if (bgstyle == "center") {
			string hexvalue = cfg->getOption("background_color");
			hexvalue = hexvalue.substr(1,6);
			image->Center(XWidthOfScreen(ScreenOfDisplay(Dpy, Scr)),
						XHeightOfScreen(ScreenOfDisplay(Dpy, Scr)),
						hexvalue.c_str());
		} else { /* plain color or error */
			string hexvalue = cfg->getOption("background_color");
			hexvalue = hexvalue.substr(1,6);
			image->Center(XWidthOfScreen(ScreenOfDisplay(Dpy, Scr)),
						XHeightOfScreen(ScreenOfDisplay(Dpy, Scr)),
						hexvalue.c_str());
		}
		Pixmap p = image->createPixmap(Dpy, Scr, Root);
		XSetWindowBackgroundPixmap(Dpy, Root, p);
		XChangeProperty(Dpy, Root, BackgroundPixmapId, XA_PIXMAP, 32,
			PropModeReplace, (unsigned char *)&p, 1);
	}
	XClearWindow(Dpy, Root);

	XFlush(Dpy);
	delete image;
}

/* Check if there is a lockfile and a corresponding process */
void App::GetLock()
{
	std::ifstream lockfile(cfg->getOption("lockfile").c_str());
	if (!lockfile) {
		/* no lockfile present, create one */
		std::ofstream lockfile(cfg->getOption("lockfile").c_str(), ios_base::out);
		if (!lockfile) {
			logStream << APPNAME << ": Could not create lock file: " <<
					cfg->getOption("lockfile").c_str() << std::endl;
			exit(ERR_EXIT);
		}
		lockfile << getpid() << std::endl;
		lockfile.close();
	} else {
		/* lockfile present, read pid from it */
		int pid = 0;
		lockfile >> pid;
		lockfile.close();
		if (pid > 0) {
			/* see if process with this pid exists */
			int ret = kill(pid, 0);
			if (ret == 0 || (ret == -1 && errno == EPERM) ) {
				logStream << APPNAME <<
					": Another instance of the program is already running with PID "
					<< pid << std::endl;
				exit(0);
			} else {
				logStream << APPNAME << ": Stale lockfile found, removing it" << std::endl;
				std::ofstream lockfile(cfg->getOption("lockfile").c_str(), ios_base::out);
				if (!lockfile) {
					logStream << APPNAME <<
						": Could not create new lock file: " << cfg->getOption("lockfile")
						<< std::endl;
					exit(ERR_EXIT);
				}
				lockfile << getpid() << std::endl;
				lockfile.close();
			}
		}
	}
}

/* Remove lockfile and close logs */
void App::RemoveLock()
{
	remove(cfg->getOption("lockfile").c_str());
}

/* Get server start check flag. */
bool App::isServerStarted()
{
	return serverStarted;
}

/* Redirect stdout and stderr to log file */
void App::OpenLog()
{
	if ( !logStream.openLog( cfg->getOption("logfile").c_str() ) ) {
		logStream <<  APPNAME << ": Could not accesss log file: " << cfg->getOption("logfile") << endl;
		RemoveLock();
		exit(ERR_EXIT);
	}
	/* I should set the buffers to imediate write, but I just flush on every << operation. */
}

/* Relases stdout/err */
void App::CloseLog()
{
	/* Simply closing the log */
	logStream.closeLog();
}

string App::findValidRandomTheme(const string& set)
{
	/* extract random theme from theme set; return empty string on error */
	string name = set;
	struct stat buf;

	if (name[name.length()-1] == ',') {
		name = name.substr(0, name.length() - 1);
	}

	Util::srandom(Util::makeseed());

	vector<string> themes;
	string themefile;
	Cfg::split(themes, name, ',');
	do {
		int sel = Util::random() % themes.size();

		name = Cfg::Trim(themes[sel]);
		themefile = string(THEMESDIR) +"/" + name + THEMESFILE;
		if (stat(themefile.c_str(), &buf) != 0) {
			themes.erase(find(themes.begin(), themes.end(), name));
			logStream << APPNAME << ": Invalid theme in config: "
				 << name << endl;
			name = "";
		}
	} while (name == "" && themes.size());
	return name;
}


void App::replaceVariables(string& input,
			   const string& var,
			   const string& value)
{
	string::size_type pos = 0;
	int len = var.size();
	while ((pos = input.find(var, pos)) != string::npos) {
		input = input.substr(0, pos) + value + input.substr(pos+len);
	}
}

/*
 * We rely on the fact that all bits generated by Util::random()
 * are usable, so we are taking full words from its output.
 */
void App::CreateServerAuth()
{
	/* create mit cookie */
	uint16_t word;
	uint8_t hi, lo;
	int i;
	string authfile;
	const char *digits = "0123456789abcdef";
	Util::srandom(Util::makeseed());
	for (i = 0; i < App::mcookiesize; i+=4) {
		word = Util::random() & 0xffff;
		lo = word & 0xff;
		hi = word >> 8;
		mcookie[i] = digits[lo & 0x0f];
		mcookie[i+1] = digits[lo >> 4];
		mcookie[i+2] = digits[hi & 0x0f];
		mcookie[i+3] = digits[hi >> 4];
	}
	/* reinitialize auth file */
	authfile = cfg->getOption("authfile");
	remove(authfile.c_str());
	putenv(StrConcat("XAUTHORITY=", authfile.c_str()));
	Util::add_mcookie(mcookie, ":0", cfg->getOption("xauth_path"),
	  authfile);
}

char* App::StrConcat(const char* str1, const char* str2)
{
	char* tmp = new char[strlen(str1) + strlen(str2) + 1];
	strcpy(tmp, str1);
	strcat(tmp, str2);
	return tmp;
}

void App::UpdatePid()
{
	std::ofstream lockfile(cfg->getOption("lockfile").c_str(), ios_base::out);
	if (!lockfile) {
		logStream << APPNAME << ": Could not update lock file: " <<
				cfg->getOption("lockfile").c_str() << endl;
		exit(ERR_EXIT);
	}
	lockfile << getpid() << endl;
	lockfile.close();
}