slim/switchuser.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 <cstdio>
#include "switchuser.h"
#include "util.h"

using namespace std;

SwitchUser::SwitchUser(struct passwd *pw, Cfg *c, const string& display,
					   char** _env)
	: cfg(c),
	  Pw(pw),
	  displayName(display),
	  env(_env)
{
}

SwitchUser::~SwitchUser() {
	/* Never called */
}

void SwitchUser::Login(const char* cmd, const char* mcookie) {
	SetUserId();
	SetClientAuth(mcookie);
	Execute(cmd);
}

void SwitchUser::SetUserId() {
	if( (Pw == 0) ||
			(initgroups(Pw->pw_name, Pw->pw_gid) != 0) ||
			(setgid(Pw->pw_gid) != 0) ||
			(setuid(Pw->pw_uid) != 0) ) {
		logStream << APPNAME << ": could not switch user id" << endl;
		exit(ERR_EXIT);
	}
}

void SwitchUser::Execute(const char* cmd) {
	chdir(Pw->pw_dir);
	execle(Pw->pw_shell, Pw->pw_shell, "-c", cmd, NULL, env);
	logStream << APPNAME << ": could not execute login command" << endl;
}

void SwitchUser::SetClientAuth(const char* mcookie) {
	string home = string(Pw->pw_dir);
	string authfile = home + "/.Xauthority";
	remove(authfile.c_str());
	Util::add_mcookie(mcookie, ":0", cfg->getOption("xauth_path"),
	  authfile);
}