PC/SC Lite interface for GNU Prolog

version 1.01, Tue May 13 2003

Written by Renaud Mariana
renaud.mariana@caramail.com



1. Introduction

The gplpcsc wrapper provides a very simple interface to the Muscle PC/SC library (www.linuxnet.com) in GNU Prolog.
The purpose of Muscle PC/SC (PC/SC Lite) is to provide a Windows(R) SCard interface in a very small form factor for communicating to smartcards and readers.

This gplpcsc wrapper helps people wishing to prototype smart-card related software by allowing command line style applications combined with the GNU Prolog built-in solver.



This software is published under the terms and conditions of the GPL, shown
below.



2. Installation

2.1 Before you install
      - Ensure that you have installed PC/SC Lite on your machine.  You must have
        the client libraries installed in order to compile and use PC/SC Lite for GNU Prolog.
        PC/SC Lite  can be obtained from:

        http://www.linuxnet.com/

      - Ensure that you have GNU Prolog installed, and the program gplc in
        your PATH. GNU prolog can be obtained from:

        http://gprolog.inria.fr/

2.2 Downloading the MUSCLE PC/SC interface for Prolog
		  - The primary site for downloading this library is
				http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/gprolog/contribs/gplpcsc/

2.3 Compiling the MUSCLE PC/SC interface for Prolog
      - Extract the source code
      	Type at the command line :

				cvs -d:pserver:anonymous@cvs.gprolog.sourceforge.net:/cvsroot/gprolog login
				cvs -z3 -d:pserver:anonymous@cvs.gprolog.sourceforge.net:/cvsroot/gprolog co contribs

      - Compiling the code
        Ensure the MUSCLE PC/SC library is reachable:
              - generally customize /etc/profile with the 2 following lines  
		LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/usr/local/lib"
		export LD_LIBRARY_PATH

        Change to the gplpcsc directory, and type "make" at the command line.


        		
3. Running the example

The program "testapdu" is created in the installation directory.  
Make sure the muscle pcsc daemon is running and a smartcard is inserted then 
  run "./testapdu" from the command line.

The output should be something like this :
ATR: [3B 3B 94 00 80 65 AF 03 0D 01 74 83 0F 90 00 ]

This example sends successively the following Apdu = [e2h,00h,04h,X,00h],
 where X= 00h to 0fh.

tr: e200040000 - 6e00, t= 152ms.
tr: e200040100 - 6e00, t= 26ms.
tr: e200040200 - 6e00, t= 19ms.
tr: e200040300 - 6e00, t= 19ms.
tr: e200040400 - 6e00, t= 19ms.
tr: e200040500 - 6e00, t= 20ms.
tr: e200040600 - 6e00, t= 22ms.
tr: e200040700 - 6e00, t= 19ms.
tr: e200040800 - 6e00, t= 19ms.
tr: e200040900 - 6e00, t= 19ms.
tr: e200040a00 - 6e00, t= 19ms.
tr: e200040b00 - 6e00, t= 22ms.
tr: e200040c00 - 6e00, t= 19ms.
tr: e200040d00 - 6e00, t= 23ms.
tr: e200040e00 - 6e00, t= 19ms.
tr: e200040f00 - 6e00, t= 19ms.
No more solutions
GNU Prolog 1.2.17
By Daniel Diaz
Copyright (C) 1999-2003 Daniel Diaz
| ?-



4. Using the Muscle PC/SC interface

The full functionality of the Muscle PC/SC client library has not been implemented.
Use of memory card is not implemented in this version.


4.1 Connecting to the PC/SC server

Templates

scard_establish_context(+atom, -integer), 
scard_establish_context(+atom),
scard_establish_context/0

Description 

scard_establish_context(MachineName, HContext) establishes a context with the pcsc driver on machine MachineName.
HContext becomes the current (implicit) pcsc context, see scard_current/4 to switch between contexts.

scard_establish_context(MachineName) same as scard_establish_context/3, HContext is set internally, see also scard_current/4 to retrieve the context.

scard_establish_context/0 applies to the local Machine (localhost), HContext is set internally.

Errors 

HContext is not a variable:	 	type_error(variable, HContext) 
pcsc daemon not running:	 	system_error('Service not available.'), 
pcsc SCardEstablishContext failed: 	system_error() 


4.2 Disconnecting from the PC/SC server

Templates 

scard_release_context(+atom),
scard_release_context/0 

Description 

scard_release_context(HContext) releases the pcsc context HContext associated to the connection to the PC/SC server. 
The current pcsc context becomes invalid.
Other current values; reader connection handle, Atr, and Protocol become also invalid (see scard_current/4). 

scard_release_context/0 applies to the current pcsc context

Errors 

HContext is invalid: 			system_error('Invalid handle.') 
pcsc daemon not running:	 	system_error('Service not available.'), 


4.3 List the readers of a PC/SC server

Templates 

scard_list_readers(+integer, -list),
scard_list_readers(-list) 

Description 

scard_list_readers(HContext, Readers) return the list of the readers available for the pcsc server associated with HContext.

scard_list_readers(Readers) applies to the current HContext.

Errors 

Readers is not a list: 		type_error(list, Readers) 
Pcsc daemon not running:  		system_error('Service not available.') 


4.4 Get Status Change

Template 

scard_get_status_change(+integer, +atom),
scard_get_status_change(+atom) 
scard_get_status_change/0 

Description 

scard_get_status_change(HContext, ReaderName) blocks for a change in state (card inserted) to occur for the reader ReaderName. 

scard_get_status_change(ReaderName) applies to the current HContext.

scard_get_status_change/0 same as scard_get_status_change/1 but uses the first reader in the list returned by scard_list_readers/2.

Errors 

HContext is not an integer: type_error(integer, HContext) 
HContext is invalid: system_error('Invalid handle.') 
ReaderName is not an atom: type_error(atom, ReaderName)
Pcsc daemon not running:  system_error('Service not available.') 


4.5 Connect to a reader

Template 

scard_connect(+integer, +atom, -integer, ?atom), 
scard_connect(+atom, -integer, ?atom), 
scard_connect((+atom),
scard_connect/0

Description 

scard_connect(HContext, ReaderName, HCard, Protocol) connects to the reader ReaderName associated to the pcsc context HContext and unifies HCard  and Protocol ('t0'  or 't1') for the reader connection. 
HCard and Protocol become the current values for the reader connection until the reader connection is closed or the values are changed with the predicate scard_current/4. 

scard_connect(ReaderName, HCard, Protocol) applies to the current pcsc connection.

scard_connect(ReaderName) applies to the current pcsc connection, HCard and Protocol are set internally (see scard_current/4). 

scard_connect/0 same as scard_connect/1 but uses the first reader in the list returned by scard_list_readers/2.

Errors 
Readers is not a variable: 		type_error(variable, Readers) 
HCard is not a variable:	 	type_error(variable, HCard) 


4.6 Disconnect from a reader

Template 

scard_disconnect(+integer),
scard_disconnect/0 

Description 
 
scard_disconnect(HCard) close the connection associated with HCard. 
The current reader connection handle, Atr and Protocol become invalid. 

scard_disconnect/0 applies to the current reader connection associated to HCard. 

Errors 

HCard is not an integer: type_error(integer, HCard) 
HCard is invalid: 			system_error('Invalid handle.').
Pcsc daemon not running:  		system_error('Service not available.').


4.7 Card Status

Template 

scard_status(+integer, -integer, -list),
scard_status(-integer, -list) 

Description 

scard_status(HCard, Status, Atr) unifies Status and Atr with status and atr of the reader connection HCard. 
Atr become the current Atr value for the connection until the reader connection is closed or  Atr is changed with predicate scard_current/4. 
  
scard_status( Status, Atr) applies to the current reader connection.

Errors

HCard is not an integer: type_error(integer, HCard) 
HCard is invalid: system_error('Invalid handle.') 
Status is not a variable: 		type_error(variable,  Integer).
Atr is not a variable: 		type_error(variable,  List).
  

4.8 Transmit APDU

Template 

scard_transmit(+integer, +atom, +list, ?list, ?list),
scard_transmit(+list, ?list, ?list)

Description 

scard_transmit(HCard, Protocol, ApduIn, ApduOut, Sw) submits the term list ApduIn to the reader 
and unifies ApduOut and Sw with the term list Apdu response and term list status word.
HCard is the reader connection handle (see scard_connect/4)
Protocol has the value t0 or t1, different values default to 't0'.
scard_transmit(ApduIn, ApduOut, Sw) applies to the current reader connection and protocol (see scard_connect/4).

Errors

HCard is not an integer: type_error(integer, HCard) 
HCard is invalid: 			system_error('Invalid handle.').
Pcsc SCardTransmit failed: system_error(...)   

4.9 Get PC/SC variables

Template 
  
scard_current(?integer, ?integer, ?atom, ?list, ?atom)

Description 

scard_current(HContext, HCard, Protocol, Atr) allows the unification with the current values used by most of the above predicates.
The aim of current/implicit values is to simplify programming of simple pcsc applications by letting the library taking care of current parameters.
See scard_establish_context/2, scard_connect/4 and scard_status/2 to know exactly which parameter is being set current.
However Programmers who wish to setup simultaneous connections with two or more pcsc servers or use several readers need probably to use predicates with the largest arity to specify exactly the resources they need and not the implicit resources.

.HContext is the current context associated to the PC/SC server set by scard_establish_context/2,
.HCard identifies the current reader set by scard_connect/4 and unset by scard_disconnect/1,
.Protocol identifies the current protocol set by scard_connect/4 and unset by scard_disconnect/1,
.Atr is the current Atr set by scard_status/2 and unset by scard_disconnect/1,
All theses contexts are cleared with scard_release_context/2

4.10 APDU Trace

Template 

scard_enable_verbose(+atom),
scard_print_trace(+atom),
scard_verbose/0,

Description

scard_enable_verbose(Verbose) dumps if Verbose is set to 'true' the APDU exchange in the form of 

tr: the_apdu_in - the_apdu_out, t= time_in_ms.

where :
 the_apdu_in  is the hexadecimal print of a list of bytes sent to the card
 the_apdu_out is the hexadecimal print of a list of bytes received from the card including the 2-bytes status word

Example of such a trace:
tr: e200040f00 - 6e00, t= 29ms.


scard_print_trace(Message) prints or not a Message depending on if APDU trace is enabled.


scard_verbose succeeds if APDU trace is enabled.



5. Examples

5.1 Example of a program that uses context explicitely 

:- include('pcsc/muscle').

start :-
	scard_establish_context(HContext, localhost),
	scard_list_readers(HContext, [Reader|_]),
	scard_connect(HContext, Reader, HCard, Protocol),

	scard_status( HCard, _, Atr),
	print( 'ATR: '), print_hex_list(Atr), nl, 

	scard_transmit(HCard, Protocol, [0xA0,0x0,0,0,0], ApduOut, Sw),

	print_hex_list(ApduOut), 
	print_hex_list(Sw), nl,

:- initialization(start).



5.2 The same program using simplified form predicates

:- include('pcsc/muscle').

start :-
	scard_establish_context,    % HContext is set current
	scard_connect,              % HCard and Protocol are set current

	scard_status(_, Atr),
	print( 'ATR: '), print_hex_list(Atr), nl, 

	scard_transmit([0xA0,0x0,0,0,0], ApduOut, Sw),

	print_hex_list(ApduOut), 
	print_hex_list(Sw), nl,

:- initialization(start).




5. Compiling with the Muscle interface

The files "muscle_c.o" must be included in your compilation, and the library
"pcsclite" must be included.  
An example of Makefile is provided in the distribution.



6. Reporting Problems

Contact the author (rmariana@caramail.com) for comments and problems
relating to this interface.



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