[Pcsclite-muscle] Support for file-descriptor based devices in pcsclite
wiktor at metacode.biz
Wed Jun 8 23:59:26 PDT 2022
On 8.06.2022 17:29, Ludovic Rousseau wrote:
> Any progress? :-)
Sorry for the delay. The project was my holiday thing and since I
returned to work I can't spend this much time on it sadly :(
The additional difficulty is that I wasn't able to find out how to get
the USB device file descriptor on desktop Linux (I think you mentioned
that this should be possible) so my work was done only on a phone
(including writing, compiling and testing). Sadly Android has a
different file layout than a regular Linux and (from my understanding)
running a daemon that listens on non-standard Unix socket path (*not*
/var/run/pcscd/pcscd.comm) would require also to compile the client
library to also reference that non-standard path.
> I propose to add a new function in the IFD Handler API.
> Something like:
> IFDHCreateChannelByFd(DWORD Lun, int FileDescriptor)
> Then you can use libusb_get_device() to get a libusb device structure
> from the file descriptor.
> I expect some code refactoring in CCID src/ccid_usb.c to avoid
> duplicating a large part of OpenUSBByName()
Thanks for your pointers! I've been looking at the code but
unfortunately got stuck in hotplug_libusb.c that, ultimately, I figured
out would not be needed since hotplug manages device additions and
removals and USB file descriptor represents a ready device.
One additional problem: at least on Android there's an utility program
that grabs the device and passes the file descriptor to another program.
An example: termux-usb -e ./usbtest /dev/bus/usb/001/002
This runs "./usbtest" with one argument: numeric parameter representing
the file descriptor (e.g. "./usbtest 7"). The question is should pcscd
be extended with an argument that it would use?
Also, if you have an idea on how could I test that on a regular desktop
Linux distribution it would be super-helpful as debugging it on a phone
is really inconvenient.
So: sorry for the delays but I can't currently spend the amount of time
I would like to on this :(
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