SCardEstablishContext: Service not available

Question

I installed the following packages:

• libusb-dev
• libusb++-0.1-4c2
• libccid
• pcscd
• libpcsclite1
• libpcsclite-dev
• List item
• libpcsc-perl
• pcsc-tools

But when I send the pcsc_scan command I received the below output :

root@bt:/# pcsc_scan
PC/SC device scanner
V 1.4.16 (c) 2001-2009, Ludovic Rousseau <[email protected]>
Compiled with PC/SC lite version: 1.5.3
SCardEstablishContext: Service not available.
root@bt:/#

Why?

Note: I use BackTrack5

Answer 1

It look like your pcscd is not running (service pcscd start).

Answer 2

Quick strace pcsc_scan reveals that it tries to open a non-existing file /var/run/pcscd/pcscd.comm:

stat("/var/run/pcscd/pcscd.comm", 0x7fff315e9dc0) = -1 ENOENT (No such file or directory)
....
SCardEstablishContext: Service not available.
...
exit_group(-1)                          = ?
+++ exited with 255 +++

And indeed it does not exist:

$ ls /var/run/pcscd/pcscd.comm
ls: cannot access '/var/run/pcscd/pcscd.comm': No such file or directory

This is because there are two parts of pcscd: pcscd.service and pcscd.socket, where the latter is responsible for that missing file. Therefore, the proper solution will be:

sudo systemctl restart pcscd.socket

Demo:

$ ls /var/run/pcscd/pcscd.comm
ls: cannot access '/var/run/pcscd/pcscd.comm': No such file or directory
$ sudo systemctl restart pcscd.socket
$ ls /var/run/pcscd/pcscd.comm
/var/run/pcscd/pcscd.comm

Now you can properly enjoy your pcsc_scan.