I just released a new version 2.0.4 of pyscard. PySCard is a python module adding smart cards support (PC/SC) to Python.

The PySCard project is available at:

• pypi
• github
• sourceforge

This version is a bug fix release.

Changes:

Just a quick article to talk about something funny.

Google Search Console Team sent me an email with the top most Google searches used to arrive on my website https://ccid.apdu.fr/.

For the month of June 2022 the second top search is: "ccid driver windows 10".

Google "think" someone will find a Windows 10 driver on https://ccid.apdu.fr/?

The Windows CCID is so hard to find or to install or is so buggy that users are searching for an alternative?

On the last 12 months the result is less worrisome. The "ccid driver windows 10" search is only 7th in the list:

Conclusion

Please propose your own explanation of this result.

Maybe I should add "Windows 10" in the web site description metadata to confuse Google search a bit more? :-)

10 years ago I documented in "PCSC API spy, third try" a way to generate PC/SC API traces when using pcsc-lite.

Since then the ecosystem has changed. This article is an update of the previous blog article with more up-to-date information.

Changes

• The pcsc-spy.py command has been renamed pcsc-spy (in 2012)
• The libpcscspy.so library has been moved from /usr/lib/ to /usr/lib/x86_64-linux-gnu/ (for Intel 64-bits CPU systems)
• opensc-tool can't be used with LD_PRELOAD= any more

Demo

As before we have two cases for the use of libpcsclite.so.1.

Applications linked with libpcsclite.so.1

This is the case of the pcsc_scan command for example.

You can use the ldd command to know what library has been dynamically linked at build time:

$ ldd /usr/bin/pcsc_scan 
	linux-vdso.so.1 (0x00007fffac11b000)
	libpcsclite.so.1 => /lib/x86_64-linux-gnu/libpcsclite.so.1 (0x00007f85a5f24000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f85a5f03000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f85a5d2a000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f85a5f4f000)

You can use the LD_PRELOAD solution by doing:

In on terminal you run the pcsc-spy program. In another terminal you run:

$ LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libpcscspy.so.0 pcsc_scan -r
libpcsclite_nospy.so.1: cannot open shared object file: No such file or directory
No reader found.

In the first terminal you get the trace:

$ pcsc-spy 
SCardEstablishContext
 i dwScope: SCARD_SCOPE_SYSTEM (0x00000002)
 o hContext: 0x0E4C693B
 => Command successful. (SCARD_S_SUCCESS [0x00000000])  [0.002456]
SCardGetStatusChange
 i hContext: 0x0E4C693B
 i dwTimeout: 0x00000000 (0)
 i cReaders: 1
 i szReader: \\?PnP?\Notification
 i  dwCurrentState:  (0x00000000)
 i  dwEventState: SCARD_STATE_IGNORE, SCARD_STATE_UNKNOWN, SCARD_STATE_UNAVAILABLE, SCARD_STATE_EMPTY, SCARD_STATE_INUSE, SCARD_STATE_MUTE (0x55EDE352031D)
 i  Atr length: 0x55EDE352032C (94480209412908)
 i  Atr: NULL
 o szReader: \\?PnP?\Notification
 o  dwCurrentState:  (0x00000000)
 o  dwEventState:  (0x00000000)
 o  Atr length: 0x55EDE352032C (94480209412908)
 o  Atr: NULL
 => Command timeout. (SCARD_E_TIMEOUT [0x8010000A])  [0.007774]
SCardListReaders
 i hContext: 0x0E4C693B
 i mszGroups: (null)
 o pcchReaders: 0x00000001
 o mszReaders: NULL
 => Cannot find a smart card reader. (SCARD_E_NO_READERS_AVAILABLE [0x8010002E])  [0.000908]
SCardListReaders
 i hContext: 0x0E4C693B
 i mszGroups: (null)
 o pcchReaders: 0x00000001
 o mszReaders: NULL
 => Cannot find a smart card reader. (SCARD_E_NO_READERS_AVAILABLE [0x8010002E])  [0.000531]

Thread 1/1
Results sorted by total execution time
total time: 0.011769 sec
0.007774 sec (  1 calls) 66.06% SCardGetStatusChange
0.002456 sec (  1 calls) 20.87% SCardEstablishContext
0.001439 sec (  2 calls) 12.23% SCardListReaders

Application loading libpcsclite.so.1

In this case you need to modify the system configuration to replace the libpcsclite.so.1 library. This is done by the install_spy.sh script. You only need to run the script once.

$ sudo bash /usr/share/doc/libpcsclite-dev/install_spy.sh
Using directory: /lib/x86_64-linux-gnu
Spying library is: /lib/x86_64-linux-gnu/libpcscspy.so.0

On Debian (and derivatives like Ubuntu) and with pcsc-lite version 1.9.8 and more the script is provided by the libpcsclite-dev package.

In on terminal you run the pcsc-spy program. In another terminal you run the program you want to spy. For example:

$ opensc-tool -a
No smart card readers found.
Failed to connect to reader: No readers found

In the first terminal you get the trace:

SCardEstablishContext
 i dwScope: SCARD_SCOPE_USER (0x00000000)
 o hContext: 0x2667F6DA
 => Command successful. (SCARD_S_SUCCESS [0x00000000])  [0.005316]
SCardListReaders
 i hContext: 0x2667F6DA
 i mszGroups: (null)
 o pcchReaders: 0x00000001
 o mszReaders: NULL
 => Cannot find a smart card reader. (SCARD_E_NO_READERS_AVAILABLE [0x8010002E])  [0.000079]
SCardReleaseContext
 i hContext: 0x2667F6DA
 => Command successful. (SCARD_S_SUCCESS [0x00000000])  [0.000074]

Thread 1/1
Results sorted by total execution time
total time: 0.007195 sec
0.005316 sec (  1 calls) 73.88% SCardEstablishContext
0.000079 sec (  1 calls)  1.10% SCardListReaders
0.000074 sec (  1 calls)  1.03% SCardReleaseContext

Do not forget to restore the system configuration using the uninstall_spy.sh script.

$ sudo bash /usr/share/doc/libpcsclite-dev/uninstall_spy.sh
Using directory: /lib/x86_64-linux-gnu

Redirection in a file

It is still possible to redirect the traces in a file. Instead of running pcsc-spy you do:

$ mkfifo ~/pcsc-spy
$ cat ~/pcsc-spy > logfile

And in another terminal you start the application as indicated above (i.e. using LD_PRELOAD= or after running install_spy.sh)

You can then analyse the logs later using:

$ pcsc-spy logfile

Remarks

Bugs found

I note that SCardReleaseContext() is not always called by pcsc_scan before exit. I just fixed this problem in pcsc-tools.

Install/uninstall

It is important to run the uninstall_spy.sh script to undo the changes made by the install_spy.sh script.

It is important you undo the changes before any execution of the ldconfig (configure dynamic linker run-time bindings) administration command. ldconfig is used, for example, during the installation of a package.

If you run uninstall_spy.sh after an execution of ldconfig you may get a broken libpcsclite installation with an error like:

$ pcsc_scan 
pcsc_scan: error while loading shared libraries:
libpcsclite.so.1: cannot open shared object file: No such file or directory

To fix te problem you can force reinstall the libpcsclite1 (or equivalent) package.

Order of execution

It is important to start pcsc-spy before the application you want to spy. If you start pcsc-spy after the application you have 2 cases:

1. if the fifo file ~/pcsc-spy does not yet exist then pcsc-spy will display nothing
2. if the fifo file ~/pcsc-spy already exists then libpcscspy.so will use it to send logs and will be blocked until something reads the file (pcsc-spy or the cat command to redirect the content)

Conclusion

I hope this update is useful.

if you have ideas to improve the logs please contact me.

I just released a new version of pcsc-lite 1.9.8.
pcsc-lite is a Free Software implementation of the PC/SC (or WinSCard) API for Unix systems. 

Changes:

1.9.8: Ludovic Rousseau
11 June 2022

• Install install_spy.sh & uninstall_spy.sh scripts in docdir
• SCardTransmit(): do not fail if receive buffer is "too large"
• SCardControl(): do not fail if receive buffer is "too large"
• fix some memory leaks on shutdown
• use a better random number generator
• Some other minor improvements

I updated my ATR parsing web site at https://smartcard-atr.apdu.fr/ to add the option to get the result not in an HTML page but as a JSON document.

If you do not yet know this service you can read "Parsing an ATR: new web site URL" to get some history. 

JSON

The URL for the JSON service is https://smartcard-atr.apdu.fr/V1/parse2json?ATR=3BFF9700008131FE4380318065B0846160FB120FFD8290000D.

It is the same as for the HTML output https://smartcard-atr.apdu.fr/parse?ATR=3BFF9700008131FE4380318065B0846160FB120FFD8290000D except you replace "parse" by "V1/parse2json" in the URL.

Of course you update the ATR parameter value to use the ATR value you want to parse.

Examples

You can use it to get the description of a particular field by piping the result in the jq command.

jq is a lightweight and flexible command-line JSON processor.

For example to get the meaning of the TA₁ byte you can use:

$ curl -s https://smartcard-atr.apdu.fr/V1/parse2json?ATR=3B12953606 | jq '.TA."1"'
{
  "description": "Fi=512, Di=16, 32 cycles/ETU (125000 bits/s at 4.00 MHz, 156250 bits/s for fMax=5 MHz)",
  "value": 149
}

Or for just the TA₁ description:

$ curl -s https://smartcard-atr.apdu.fr/V1/parse2json?ATR=3B90160187 | jq '.TA."1".description'
"Fi=372, Di=32, 11.625 cycles/ETU (344086 bits/s at 4.00 MHz, 430107 bits/s for fMax=5 MHz)"

 

Card matching

I also added the possibility to get the cards matching a given ATR.

For example: https://smartcard-atr.apdu.fr/V1/match?ATR=3B8F800180318065B0850300EF120FFE82900072

$ curl -s https://smartcard-atr.apdu.fr/V1/match?ATR=3B8F800180318065B0850300EF120FFE82900072 | jq
{
  "3B 8F 80 01 80 31 80 65 B0 .. .. .. .. 12 0F FE 82 90 00 ..": [
    "IDPrime MD 3810 T=Contactless (Prox DU)"
  ],
  "3B 8F 80 01 80 31 80 65 B0 85 03 00 EF 12 0F FE 82 90 00 72": [
    "Gemalto IDPrime MD 3840",
    "http://www.gemalto.com/dwnld/6891_IDPrimeMD3840_Product_Datasheet_May14.pdf"
  ]
}

Because of the joker mechanism using the character '.' it is possible that one ATR matches more than one "card".

Conclusion

If you have ideas how to improve the service just tell me.

Sample C sample

We start with the following sample.c program:

01: #include <stdio.h>
02: #include <stdlib.h>
03: #include <winscard.h>
04: 
05: #define CHECK(f, rv) \
06:  if (SCARD_S_SUCCESS != rv) \
07:  { \
08:   printf(f ": %s\n", pcsc_stringify_error(rv)); \
09:   return -1; \
10:  }
11: 
12: int main(void)
13: {
14:     LONG rv;
15: 
16:     SCARDCONTEXT hContext;
17:     LPTSTR mszReaders;
18:     DWORD dwReaders;
19: 
20:     rv = SCardEstablishContext(SCARD_SCOPE_SYSTEM, NULL, NULL, &hContext);
21:     CHECK("SCardEstablishContext", rv)
22: 
23:     rv = SCardListReaders(hContext, NULL, NULL, &dwReaders);
24:     CHECK("SCardListReaders", rv)
25: 
26:     mszReaders = calloc(dwReaders, sizeof(char));
27:     rv = SCardListReaders(hContext, NULL, mszReaders, &dwReaders);
28:     CHECK("SCardListReaders", rv)
29:     printf("1st reader name: %s\n", mszReaders);
30: 
31:     free(mszReaders);
32: 
33:     rv = SCardReleaseContext(hContext);
34:     CHECK("SCardReleaseContext", rv)
35: 
36:     return 0;
37: }
38: 

Makefile

I used this Makefile

# Linux
PCSC_CFLAGS := $(shell pkg-config --cflags libpcsclite)
LDLIBS := $(shell pkg-config --libs libpcsclite)

CFLAGS = $(PCSC_CFLAGS) -g

sample: sample.c

clean:
	rm -f sample

Output

Compilation and execution give:

$ make
cc -pthread -I/usr/include/PCSC -g   sample.c  -lpcsclite -o sample
$ ./sample 
1st reader name: Alcor Micro AU9540 00 00

It looks like everything is correct.

But can you find the problem?

 

Valgrind is your friend

valgrind is a very nice tool to debug issues.

Valgrind is an instrumentation framework for building dynamic analysis tools. There are Valgrind tools that can automatically detect many memory management and threading bugs, and profile your programs in detail. You can also use Valgrind to build new tools.

valgrind sees a problem:

$ valgrind --track-origins=yes ./sample 

==99878== Memcheck, a memory error detector
==99878== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==99878== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==99878== Command: ./sample
==99878== 
==99878== Conditional jump or move depends on uninitialised value(s)
==99878==    at 0x486E02E: SCardListReaders (in /usr/lib/x86_64-linux-gnu/libpcsclite.so.1.0.0)
==99878==    by 0x109210: main (sample.c:23)
==99878==  Uninitialised value was created by a stack allocation
==99878==    at 0x109199: main (sample.c:13)
==99878== 
1st reader name: Alcor Micro AU9540 00 00
==99878== 
==99878== HEAP SUMMARY:
==99878==     in use at exit: 112 bytes in 4 blocks
==99878==   total heap usage: 10 allocs, 6 frees, 1,434 bytes allocated
==99878== 
==99878== LEAK SUMMARY:
==99878==    definitely lost: 0 bytes in 0 blocks
==99878==    indirectly lost: 0 bytes in 0 blocks
==99878==      possibly lost: 0 bytes in 0 blocks
==99878==    still reachable: 112 bytes in 4 blocks
==99878==         suppressed: 0 bytes in 0 blocks
==99878== Rerun with --leak-check=full to see details of leaked memory
==99878== 
==99878== For lists of detected and suppressed errors, rerun with: -s
==99878== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

Using uninitialized variables is bad. It creates bugs that declare at random time and are not easy to find.

SCardListReaders

The problem is at line 23 which is:

23:     rv = SCardListReaders(hContext, NULL, NULL, &dwReaders);

If we read the documentation for SCardListReaders() we have:

Returns a list of currently available readers on the system.

mszReaders is a pointer to a character string that is allocated by the application. If the application sends mszGroups and mszReaders as NULL then this function will return the size of the buffer needed to allocate in pcchReaders.

If *pcchReaders is equal to SCARD_AUTOALLOCATE then the function will allocate itself the needed memory. Use SCardFreeMemory() to release it.

Parameters

[in]	hContext	Connection context to the PC/SC Resource Manager.
[in]	mszGroups	List of groups to list readers (not used).
[out]	mszReaders	Multi-string with list of readers.
[in,out]	pcchReaders	Size of multi-string buffer including NULL's.

You can note that the parameter pcchReaders is in and out. This is because the value is compared to SCARD_AUTOALLOCATE. So the value of pcchReaders shall be set before calling SCardListReaders().

The fix is simple. Just update line 18 like this:

18: DWORD dwReaders = 0;

 

Looking for problems

What happens if we initialize dwReaders to the special value SCARD_AUTOALLOCATE instead of 0?

18: DWORD dwReaders = SCARD_AUTOALLOCATE;

We build and run the sample:

$ ./sample 
SCardListReaders: Invalid parameter given.

The execution of SCardListReaders() fails.

23:     rv = SCardListReaders(hContext, NULL, NULL, &dwReaders);

This is because we are asking SCardListReaders() to allocate and store the result in the parameter mszReaders. But in our sample this parameter is NULL. pcsc-lite has a check for that and returns an error code.

Instead of using NULL we could use something else like 0x1234.

23:     rv = SCardListReaders(hContext, NULL, 0x1234, &dwReaders);

This time we have a nice crash:

$ ./sample 
Segmentation fault

This is because we asked SCardListReaders() to write at the address 0x1234. This address is, in general, not valid.

This problem could happen if you use something like:

23:     rv = SCardListReaders(hContext, NULL, mszReaders, &dwReaders);

And both variables mszReaders and dwReaders are uninitialized, and by a total lack of luck dwReaders has the value SCARD_AUTOALLOCATE (i.e. -1).

 

GnuPG

The problem was found in by oddlama and reported to PCSC at "pcscd fails to read future yubikeys after removing a yubikey, until restarted #125".

The problem is not in pcsc-lite but in GnugPG. So I reported the problem at "SCardListReaders: Conditional jump or move depends on uninitialised value(s)".

WinSCard API

macOS does not support (yet) the value SCARD_AUTOALLOCATE. But pcsc-lite and Windows WinSCard do.

I agree the API to use SCARD_AUTOALLOCATE is ugly. We pass the address of a buffer pointer in a parameter that is a buffer pointer. We have to cast the variable like I did in the C sample like:

  dwReaders = SCARD_AUTOALLOCATE;
  rv = SCardListReaders(hContext, NULL, (LPTSTR)&mszReaders, &dwReaders);

This feature is a Microsoft extension that is not present in the PCSC workgroup specification.

Conclusion

I think the problem is not very known and should be better documented. That was my motivation for writting this blog article.

Morality: in C language, always initialize your variables to a known/safe value (like 0).

I just released a new version of pcsc-lite 1.9.7.
pcsc-lite is a Free Software implementation of the PC/SC (or WinSCard) API for Unix systems. 

 

 Changes

1.9.7: Ludovic Rousseau
13 May 2022

• disable strict compilation by default
• fix 3 warnings

Issues with strict compilation

In the previous version (1.9.6) I enabled a strict compilation option by default. The compiler was configured to use the -Werror argument. The effect is to transform warnings into errors. The compilation would fail instead of just displaying a warning.

On my side I had no warnings so I was confident.

But some build systems use a different set of default compilation arguments. For example Arch Linux or openSUSE Tumbleweed use the argument -flto=auto to perform some link-time optimizer.

This option generated 3 warnings. The warnings are minor but since the compilation used -Werror they were treated as errors and the compilation failed.

Sorry for generating the problem. Thanks to Axel Braun and frederik for reporting the failure.

I just released a new version of pcsc-lite 1.9.6.
pcsc-lite is a Free Software implementation of the PC/SC (or WinSCard) API for Unix systems. 

 

Changes:

1.9.6: Ludovic Rousseau
11 May 2022

• do not fail reader removal in some specific cases (USB/Thunderbolt port)
• improve documentation regarding /etc/reader.conf.d/
• SCardGetStatusChange: speedup the case DISABLE_AUTO_POWER_ON
• configure:
• add --disable-strict option
  By default the compiler arguments are now:
  -Wall -Wextra -Wno-unused-parameter -Werror ${CFLAGS}
• fail if flex is not found
• fix different data races
• pcscdaemon: -v displays internal constants values: MAX_READERNAME & PCSCLITE_MAX_READERS_CONTEXTS
• Some other minor improvements

 

Reader removal issue

The problem with reader removal is that, with some hardware configurations, the USB bus is removed when the USB device is disconnected. You can see that using the libusb command.

Before connecting the device:

Bus 002 Device 002: ID 0bda:0328 Realtek Semiconductor Corp. USB3.0-CRW
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 1bcf:2c6b Sunplus Innovation Technology Inc. HD WebCam
Bus 001 Device 005: ID 1044:7a39 Chu Yuen Enterprise Co., Ltd USB-HID Keyboard
Bus 001 Device 004: ID 8087:0a2b Intel Corp. Bluetooth wireless interface
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

After connecting the Yubikey token

Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 002: ID 1050:0407 Yubico.com Yubikey 4/5 OTP+U2F+CCID
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 002: ID 0bda:0328 Realtek Semiconductor Corp. USB3.0-CRW
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 1bcf:2c6b Sunplus Innovation Technology Inc. HD WebCam
Bus 001 Device 005: ID 1044:7a39 Chu Yuen Enterprise Co., Ltd USB-HID Keyboard
Bus 001 Device 004: ID 8087:0a2b Intel Corp. Bluetooth wireless interface
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

The new lines are: 

• Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
• Bus 003 Device 002: ID 1050:0407 Yubico.com Yubikey 4/5 OTP+U2F+CCID
• Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

2 new USB buses are created 003 & 004. The Yubikey token is connected on the bus 003.

After removing the Yubikey

Bus 002 Device 002: ID 0bda:0328 Realtek Semiconductor Corp. USB3.0-CRW
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 1bcf:2c6b Sunplus Innovation Technology Inc. HD WebCam
Bus 001 Device 005: ID 1044:7a39 Chu Yuen Enterprise Co., Ltd USB-HID Keyboard
Bus 001 Device 004: ID 8087:0a2b Intel Corp. Bluetooth wireless interface
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

The USB buses 3 & 4 have disappeared. This confused pcsc-lite. The token was not removed for pcsc-lite and caused the generation of log errors. This is now fixed.

It looks like the problem occurred with a USB-C + Thunderbolt port and was reported in "pcscd fails to read future yubikeys after removing a yubikey, until restarted #125" and "Yubikey 5c Reader "stuck" #57".

In 2010 I started to write about the different programming languages you can use to talk to a smart card and a smart card reader.

12 years later I have 30 languages in the list.

They are, in alphabetical order:

1. Ada
2. C
3. C#
4. C for UEFI
5. Common Lisp
6. Elixir
7. Erlang
8. Flutter/Dart
9. Free Pascal (Lazarus)
10. go
11. Java
12. JavaScript (Node.js)
13. Java using intarsys smartcard-io
14. Kotlin
15. lua
16. Objective-C (synchronous)
17. Objective-C (using Crypto Token Kit)
18. OCaml
19. Perl
20. PHP5
21. PHP (dead upstream as 11 January 2015)
22. Prolog
23. Python
24. Python (using python-pcsclite)
25. Ruby
26. Rust
27. Scala
28. scriptor
29. Smart Card Connector on Chromebook
30. Swift (using Crypto Token Kit)

Top Computer Languages

Different lists exist for the top computer languages popularity. I will use the TIOBE Index for April 2022.

The "support" column indicates if the language has a smart card API available.

#	Language	support
1	Python	Yes
2	C	Yes
3	Java	Yes
4	C++	Yes
5	C#	Yes
6	Visual Basic	?
7	JavaScript	Yes
8	Assembly	?
9	SQL	?
10	PHP	Yes
11	R	?
12	Pascal	Yes
13	Go	Yes
14	Swift	Yes
15	Ruby	Yes
16	Classic Visual Basic	?
17	Objective-C	Yes
18	Perl	Yes
19	Lua	Yes
20	Mathlab	?
21	SAS	?
22	Prolog	Yes
23	(Visual) FoxPro	?
24	Scratch	?
25	COBOL	?
26	Julia	?
27	Kotlin	Yes
28	Rust	Yes
29	Ada	Yes
30	Lisp	Yes
31	Fortran	?
32	Groovy	?
33	VBScript	?
34	PL/SQL	?
35	D	?
36	Scala	Yes
37	Haskell	?
38	Dart	Yes

Comments

It should be easy to call the C WinSCard API from assembly language. So the answer could be "yes". I learned assembly language with a Motorola 6809 and then a Motorola 68000. I am not a fan of the Intel x86 assembly language with its very strange register names (to be backward compatible). Yes, I could also use ARM or RISC-V CPUs. I let the exercise to write an example in assembly language to the readers.

Not listed

Some programming languages are not listed in the TIOBE index but do provide a PC/SC wrapper:

• Elixir
• Erlang
• OCaml

Windows technologies

Some languages are specific to the Microsoft Windows system. I can't use them since I do not use Windows. They are:

• Visual Basic
• Classic Visual Basic
• VBScript
• Visual FoxPro.

It looks like Visual Basic is also available for GNU/Linux. But I don't want to invest time in these technologies.

Also note that all the computer languages with PC/SC support exist in a Free Software implementation. I am not sure for the Microsoft languages.

Language I would be surprised to get PC/SC support

R and SAS are languages used for statistics.

Scratch is used for education.

Mathlab is for numeric computing.

COBOL is very old. I do not expect any COBOL program needing access to smart cards. Same remark for Fortran. COBOL and Fortran are still used and it looks like it is possible to call C functions from both of them. So there is hope ☺.

Languages that could have a PC/SC wrapper

• Julia
  it should be possible to use PyCall and call the Python PC/SC wrapper.
  
• D
• Haskell
  

What I had not yet found

SQL: (SQL Server) PC/SC List Smart Card Readers (and USB Tokens)

This is for SQL Server, so may be limited to the Microsoft product and not the SQL language.

Conclusion

It was a lot of fun to discover and write a sample codes for all the 30 languages.

For some (4) of the PC/SC wrappers I am the maintainer so writing a sample code was easy.

The list is not finished and may never be as new programming languages are created from time to time. If you want me to add a new language please contact me.

To continue the list of PC/SC wrappers initiated in 2010 with "PC/SC sample in different languages" I now present a new sample code in Erlang.

I use the PC/SC wrapper for Erlang: erlang-pcsc from Alex Wilson. The project description is "libpcsc NIF binding for erlang". The license is BSD 2 clause.

This is the same wrapper I used in the previous blog article "PC/SC sample in Elixir".

The wrapper is available on Hex.pm (The package manager for the Erlang ecosystem) at https://hex.pm/packages/pcsc.

API documentation is available at https://arekinath.github.io/erlang-pcsc/index.html

 

Create a new application

$ rebar3 new app blog
===> Writing blog/src/blog_app.erl
===> Writing blog/src/blog_sup.erl
===> Writing blog/src/blog.app.src
===> Writing blog/rebar.config
===> Writing blog/.gitignore
===> Writing blog/LICENSE
===> Writing blog/README.md

Install pcsc module

Edit the file rebar.config to use:

{deps, [pcsc]}.
{erl_opts, [{i, "_build/default/lib/pcsc/include/"}]}. 

The erl_opts option is needed because we will include one header file from the pcsc module. Maybe it is possible to have a less ugly/hardcoded path.

Upgrade the dependencies:

$ rebar3 upgrade --all
===> Verifying dependencies...
===> Fetching pcsc v1.3.1
===> Fetching rebar3_hex v7.0.1
===> Fetching hex_core v0.8.4
===> Fetching verl v1.1.1
===> Analyzing applications...
===> Compiling verl
===> Compiling hex_core
===> Compiling rebar3_hex
_build/default/plugins/rebar3_hex/src/rebar3_hex_organization.erl:391:5: Warning: public_key:ssh_encode/2 is deprecated and will be removed in OTP 26; use ssh_file:encode/2 instead

===> Fetching lager v3.9.2
===> Fetching goldrush v0.1.9
===> No upgrade needed for pcsc
===> No upgrade needed for lager
===> No upgrade needed for goldrush

Build the dependencies:

$ rebar3 compile
===> Verifying dependencies...
make : on entre dans le répertoire « /home/rousseau/Documents/blog/erlang/_build/default/lib/pcsc/c_src »
cc  -Wall -g -O2 -Wextra -pipe -funsigned-char -fstrict-aliasing -Wchar-subscripts -Wundef -Wshadow -Wcast-align -Wwrite-strings -Wunused -Wuninitialized -Wpointer-arith -Wredundant-decls -Winline -Wformat -Wformat-security -Wswitch-enum -Winit-self -Wmissing-include-dirs -Wempty-body -fdiagnostics-color=auto -Wmissing-prototypes -Wstrict-prototypes -Wold-style-definition -Wbad-function-cast -Wnested-externs  -Wmissing-declarations -fPIC -I /usr/lib/erlang/erts-12.3.1/include/ -I /usr/lib/erlang/lib/erl_interface-5.2.2/include -pthread -I/usr/include/PCSC  -c -o /home/rousseau/Documents/blog/erlang/_build/default/lib/pcsc/c_src/pcsc_nif.o /home/rousseau/Documents/blog/erlang/_build/default/lib/pcsc/c_src/pcsc_nif.c
[...]
cc /home/rousseau/Documents/blog/erlang/_build/default/lib/pcsc/c_src/pcsc_nif.o -shared -L /usr/lib/erlang/lib/erl_interface-5.2.2/lib -lei -lpcsclite -o /home/rousseau/Documents/blog/erlang/_build/default/lib/pcsc/c_src/../priv/pcsc_nif.so
make : on quitte le répertoire « /home/rousseau/Documents/blog/erlang/_build/default/lib/pcsc/c_src »
===> Analyzing applications...
===> Compiling goldrush
===> Compiling lager
===> Compiling pcsc
===> Analyzing applications...
===> Compiling blog

Edit the file src/blog.app.src to declare the pcsc application.

It should look like:

[...]
  {applications,
   [kernel,
    stdlib,
    pcsc
   ]},
[...]

Sample code

Create the source code file src/blog.erl with the content:

-module(blog).
-export([main/0]).

-include("iso7816.hrl").

main() ->
  % get all the available readers
  {ok, Readers} = pcsc_card_db:list_readers(),

  % use the first reader
  [Reader | _] = Readers,
  io:fwrite("Using: ~s~n", [Reader]),

  % connect
  {ok, Card} = pcsc_card:start_link(Reader, shared, [t1, t0]),

  % select applet
  Aid = << 160, 0, 0, 0, 98, 3, 1, 12, 6, 1 >>,
  Select_apdu = #apdu_cmd{cla = iso, ins = select, p1 = 4, p2 = 0, data = Aid},
  {ok, Select_replies} = pcsc_card:command(Card, Select_apdu),
  io:write(Select_replies),
  io:fwrite("~n"),

  % command
  Command_apdu = #apdu_cmd{ cla = iso, ins = 0, p1 = 0, p2 = 0 },
  {ok, Command_replies} = pcsc_card:command(Card, Command_apdu),
  io:write(Command_replies),
  io:fwrite("~n"),

  % extract the answer
  [Reply | _] = Command_replies,
  case Reply of
    {apdu_reply, _, ok, Msg} ->
      io:write(binary_to_atom(Msg)),
      io:fwrite("~n");
    {apdu_reply, _, error, _} ->
      io:fwrite("Error~n")
  end.

Output

Generating a standalone Erlang application looks complex. But you can test your code using the interactive shell.

$ rebar3 shell
===> Verifying dependencies...
===> Analyzing applications...
===> Compiling blog
Erlang/OTP 24 [erts-12.3.1] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [jit]

Eshell V12.3.1  (abort with ^G)
===> Booted syntax_tools
===> Booted compiler
===> Booted goldrush
===> Booted lager
===> Booted pcsc
===> Booted blog
 
1> blog:main().
Using: Gemalto PC Twin Reader 00 00
[{apdu_reply,t1,ok,none}]
[{apdu_reply,t1,ok,<<72,101,108,108,111,32,119,111,114,108,100,33>>}]
'Hello world!'
ok
2> 

Comments

ehecatl

An older github project also exist at https://github.com/zgbjgg/ehecatl
Its description is "An erlang library for read/write nfc smart cards".

I filed 2 issues in 2020: Missing <PCSC/winscard.h>? and More complete PC/SC wrapper? but got no answer.

This project has not seen any commit since 2014.

So I guess this project is dead.

erlang-pcsc 

The only problem I have with erlang-pcsc is that, if no smart card reader is connected, I get:

$ rebar3 shell
===> Verifying dependencies...
===> Analyzing applications...
===> Compiling blog
Erlang/OTP 24 [erts-12.3.1] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [jit]

Eshell V12.3.1  (abort with ^G)
1> ===> Booted syntax_tools
===> Booted compiler
===> Booted goldrush
===> Booted lager
===> Booted pcsc
===> Booted blog
23:31:49.563 [warning] got pcsc_reader_error: {error,{pcsc_error,-2146435026,no_readers,"Cannot find a smart card reader."}}; restarted ok
23:31:49.622 [warning] got pcsc_reader_error: {error,{pcsc_error,-2146435026,no_readers,"Cannot find a smart card reader."}}; restarted ok
23:31:49.677 [warning] got pcsc_reader_error: {error,{pcsc_error,-2146435026,no_readers,"Cannot find a smart card reader."}}; restarted ok
23:31:49.729 [warning] got pcsc_reader_error: {error,{pcsc_error,-2146435026,no_readers,"Cannot find a smart card reader."}}; restarted ok
23:31:49.782 [warning] got pcsc_reader_error: {error,{pcsc_error,-2146435026,no_readers,"Cannot find a smart card reader."}}; restarted ok
23:31:49.836 [warning] got pcsc_reader_error: {error,{pcsc_error,-2146435026,no_readers,"Cannot find a smart card reader."}}; restarted ok
23:31:49.889 [warning] got pcsc_reader_error: {error,{pcsc_error,-2146435026,no_readers,"Cannot find a smart card reader."}}; restarted ok
23:31:49.941 [warning] got pcsc_reader_error: {error,{pcsc_error,-2146435026,no_readers,"Cannot find a smart card reader."}}; restarted ok
23:31:49.992 [warning] got pcsc_reader_error: {error,{pcsc_error,-2146435026,no_readers,"Cannot find a smart card reader."}}; restarted ok
23:31:50.044 [warning] got pcsc_reader_error: {error,{pcsc_error,-2146435026,no_readers,"Cannot find a smart card reader."}}; restarted ok
etc...

The error -2146435026 is SCARD_E_NO_READERS_AVAILABLE and is not really an error for SCardListReaders().

I filed a github issue [warning] got pcsc_reader_error: {error,{pcsc_error,-2146435026,no_readers,"Cannot find a smart card reader."}}; restarted ok #4 but with no answer so far.

Conclusion

Thanks Alex for the Erlang PC/SC wrapper. And thanks tofferoma, from the elixir forum, for your help in writing the Erlang sample code.

If you work on a Free Software PC/SC wrapper that is not yet in my list please let me know.