path: root/core/opie-login/loginapplication.cpp

/*
               =.            This file is part of the OPIE Project
             .=l.            Copyright (c)  2002 Robert Griebl <sandman@handhelds.org>
           .>+-=
 _;:,     .>    :=|.         This file is free software; you can
.> <`_,   >  .   <=          redistribute it and/or modify it under
:`=1 )Y*s>-.--   :           the terms of the GNU General Public
.="- .-=="i,     .._         License as published by the Free Software
 - .   .-<_>     .<>         Foundation; either version 2 of the License,
     ._= =}       :          or (at your option) any later version.
    .%`+i>       _;_.
    .i_,=:_.      -<s.       This file is distributed in the hope that
     +  .  -:.       =       it will be useful, but WITHOUT ANY WARRANTY;
    : ..    .:,     . . .    without even the implied warranty of
    =_        +     =;=|`    MERCHANTABILITY or FITNESS FOR A
  _.=:.       :    :=>`:     PARTICULAR PURPOSE. See the GNU General
..}^=.=       =       ;      Public License for more details.
++=   -.     .`     .:
 :     =  ...= . :.=-        You should have received a copy of the GNU
 -.   .:....=;==+<;          General Public License along with this file;
  -_. . .   )=.  =           see the file COPYING. If not, write to the
    --        :-=`           Free Software Foundation, Inc.,
                             59 Temple Place - Suite 330,
                             Boston, MA 02111-1307, USA.

*/

#include <pwd.h>
#include <grp.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/wait.h>

#ifdef USEPAM
extern "C" {
#include <security/pam_appl.h>
}
#else
#include <crypt.h>
#include <shadow.h>
#endif

#include "loginapplication.h"

LoginApplication *lApp;

LoginApplication::LoginApplication ( int &argc, char **argv, pid_t parentpid )
	: QPEApplication ( argc, argv, GuiServer )
{
	lApp = this;
	m_parentpid = parentpid;
}

const char *LoginApplication::s_username = 0;

#ifdef USEPAM

const char *LoginApplication::s_pam_password = 0;

int LoginApplication::pam_helper ( int num_msg, const struct pam_message **msg, struct pam_response **resp, void * )
{
	int replies = 0;
	struct pam_response *reply = 0;
	int size = sizeof( struct pam_response );

	for ( int i = 0; i < num_msg; i++ ) {
		switch ( msg [i]-> msg_style ) {
			case PAM_PROMPT_ECHO_ON: // user name given to PAM already
				return PAM_CONV_ERR;

			case PAM_PROMPT_ECHO_OFF: // wants password
				reply = (struct pam_response *) ::realloc ( reply, size );
				if ( !reply )
					return PAM_CONV_ERR;
				size += sizeof( struct pam_response );

				reply [replies]. resp_retcode = PAM_SUCCESS;
				reply [replies]. resp = ::strdup ( s_pam_password );
				replies++; // PAM frees resp
				break;

			case PAM_TEXT_INFO:
				break;

			default:
				/* unknown or PAM_ERROR_MSG */
				if ( reply )
					::free ( reply );
				return PAM_CONV_ERR;
		}
	}
	if ( reply )
		*resp = reply;
	return PAM_SUCCESS;
}


bool LoginApplication::checkPassword ( const char *user, const char *pass )
{
	static struct pam_conv conv = { &LoginApplication::pam_helper, 0 };

	int pam_error;
	pam_handle_t *pamh = 0;

	pam_error = ::pam_start( "xdm", user, &conv, &pamh );
	if ( pam_error == PAM_SUCCESS ) {
		s_pam_password = pass;
		pam_error = ::pam_authenticate ( pamh, 0 );
		s_pam_password = 0;
	}
	::pam_end ( pamh, pam_error );
	return ( pam_error == PAM_SUCCESS );
}

#else

bool LoginApplication::checkPassword ( const char *user, const char *pass )
{
	char *encrypted, *correct;
	struct passwd *pw;

	if ( !user || !pass )
		return false;

	pw = ::getpwnam ( user );

	if ( !pw )
		return false;

	if (( ::strcmp ( pw-> pw_passwd, "x" ) == 0 ) || ( ::strcmp ( pw-> pw_passwd, "*" ) == 0 )) {
		struct spwd *sp = ::getspnam ( pw-> pw_name );

		if ( !sp )
			return false;

		correct = sp-> sp_pwdp;
	}
	else
		correct = pw-> pw_passwd;

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

	encrypted = ::crypt ( pass, correct );
	return ( ::strcmp ( encrypted, correct ) == 0 );
}

#endif

bool LoginApplication::changeIdentity ( )
{
	const char *DEFAULT_LOGIN_PATH      = "/bin:/usr/bin";
	const char *DEFAULT_ROOT_LOGIN_PATH = "/usr/sbin:/bin:/usr/bin:/sbin";

	if ( !s_username )
		return false;
	struct passwd *pw = ::getpwnam ( s_username );
	if ( !pw )
		return false;

	// we are still root at this point - try to run the pre-session script
	if ( !runRootScript ( "OPIEDIR", "share/opie-login/pre-session", s_username ))
		qWarning ( "failed to run $OPIEDIR/share/opie-login/pre-session" );

	bool fail = false;
	fail |= ( ::initgroups ( pw-> pw_name, pw-> pw_gid ));
	::endgrent ( );
	fail |= ( ::setgid ( pw-> pw_gid ));
	fail |= ( ::setuid ( pw-> pw_uid ));

	fail |= ( ::chdir ( pw-> pw_dir ) && ::chdir ( "/" ));

	fail |= ( ::setenv ( "HOME",    pw-> pw_dir, 1 ));
	fail |= ( ::setenv ( "SHELL",   pw-> pw_shell, 1 ));
	fail |= ( ::setenv ( "USER",    pw-> pw_name, 1 ));
	fail |= ( ::setenv ( "LOGNAME", pw-> pw_name, 1 ));
	fail |= ( ::setenv ( "PATH",    ( pw-> pw_uid ? DEFAULT_LOGIN_PATH : DEFAULT_ROOT_LOGIN_PATH ), 1 ));

	return !fail;
}

bool LoginApplication::login ( )
{
	execUserScript ( "HOME", ".opie-session" );
	execUserScript ( "OPIEDIR", "share/opie-login/opie-session" );
	execUserScript ( "OPIEDIR", "bin/qpe" );
	
	qWarning ( "failed to start an Opie session" );
	return false;
}

void LoginApplication::logout ( )
{
	// we are now root again - try to run the post-session script
	if ( !runRootScript ( "OPIEDIR", "share/opie-login/post-session" ))
		qWarning ( "failed to run $OPIEDIR/scripts/post-session" );	
}


static char *buildarg ( const char *base, const char *script )
{
	const char *dir = base ? ::getenv ( base ) : "/";
	char *arg = new char [::strlen ( dir ) + ::strlen ( script ) + 2];

	::strcpy ( arg, dir );
	::strcat ( arg, "/" );
	::strcat ( arg, script );

	return arg;
}

bool LoginApplication::runRootScript ( const char *base, const char *script, const char *param )
{
	bool res = false;
	char *arg = buildarg ( base, script );

	struct stat st;
	if (( ::stat ( arg, &st ) == 0 ) && ( st. st_uid == 0 )) {
		pid_t child = ::fork ( );	
		
		if ( child == 0 ) {
			::execl ( "/bin/sh", "-sh", arg, param, 0 );
			::_exit ( -1 );
		}
		else if ( child > 0 ) {
			int status = 0;
		
			while ( ::waitpid ( child, &status, 0 ) < 0 ) { }
			res = ( WIFEXITED( status )) && ( WEXITSTATUS( status ) == 0 );
		}
	}
		
	delete [] arg;
	return res;
}

void LoginApplication::execUserScript ( const char *base, const char *script )
{
	char *arg = buildarg ( base, script );

	struct stat st;
	if ( ::stat ( arg, &st ) == 0 ) {
		if ( st. st_mode & S_IXUSR )
			::execl ( "/bin/sh", "-sh", "-c", arg, 0 );
		else
			::execl ( "/bin/sh", "-sh", arg, 0 );
	}
}

const char *LoginApplication::loginAs ( )
{
	return s_username;
}

void LoginApplication::setLoginAs ( const char *name )
{
	s_username = name;
}

QStringList LoginApplication::allUsers ( )
{
	struct passwd *pwd;
	QStringList sl;

	while (( pwd = ::getpwent ( ))) {
		if (( pwd-> pw_uid == 0 ) || ( pwd-> pw_uid >= 500 && pwd-> pw_uid < 65534 ))
			sl << QString ( pwd-> pw_name );
	}

	::endpwent ( );

	return sl;
}

void LoginApplication::quitToConsole ( )
{
	QPEApplication::quit ( );
	::kill ( m_parentpid, SIGTERM );
}