Compiling pycryptodome (python2.7)

[Ircama]

Can you please advise on how pycryptodome can be compiled (Python)?

I was able to read BLE Advertisements through an Ai-Thinker TB-03F-KIT module connected via USB (/dev/ttyUSB0, Driver=ch341,
it needs a simple firmware and a Python code, I'll document this as soon as it is completed), but I would need to decode cyphered messages from BLE devices (like Xiaomi Mijia BLE sensors).

At the moment we only have pycrypto compiled, which does not support AES.MODE_CCM.

Thanks a lot!

[fda77]

You habe to add this llike the other pythong things in /make/libs/python-*

[Ircama]

It's really hard for me to understand :-(. I think the configuration should need a directory under freetz-ng/tree/master/make/pkgs, e.g., python-pycryptodome.

Then I need to create:

• the "Config.in" file; this looks easy, like this
• the "python-pycryptodome.mk"; this has to be developed similarly to python-pycrypto.mk; I think it should point to https://pypi.org/project/pycryptodome/; and somewhere it should be hooked to the toolchain I think
• in case, a "patches" folder, including all needed corrections to the compilation

Really so complex?

[fda77]

You have simplified it, but yes

And test it with
make python-XXXX-source
or make python-XXXX-autofix
or make python-XXXX-recompile

[Ircama]

Adding a Python module is too complex, it is unclear how to cross-compile a Python wheel. Trying to understand how it was done for some packages, I checked commits that were made many years ago, nothing recent. Besides the device does not have a compiler (you need to cross-compile into some other place). Also Python is the old 2.7. I give up.

Maybe calling C functions from Python is easier.

While the standard build of the firmware works, if I create a new project I cannot even get the cross-compiler to produce an executable that the device can run.

For instance, I have freetz-ng installed in ~/freetz-ng (Ubuntu 22.4).

cd freetz-ng
mkdir example
cd example
cat hello_world.c
#include <stdio.h>
#include <stdlib.h>
int main(void){
  printf("Hello world!\n");
  return 0;
}

Which is the right syntax to compile it so that the executable, when moved to the device, runs there?

Also, how this function (my_function.c) can be compiled to create my_function.so running on the device?

int square(int i) {
	return i * i;
}

[fda77]

I never did this, maybe you find some docs if you search for it

[Ircama]

Perhaps I found the answer:

• Compilation (cross compiling):

/home/$USER/freetz-ng/toolchain/build/mips_gcc-13.2.0_uClibc-1.0.45-nptl_kernel-4.9/mips-linux-uclibc/bin/mips-linux-uclibc-gcc -march=34kc -mtune=34kc -msoft-float -Ofast -pipe -Wa,--trap -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Wl,-I/usr/lib/freetz/ld-uClibc.so.1 -o hello_world hello_world.c

/home/$USER/freetz-ng/toolchain/build/mips_gcc-13.2.0_uClibc-1.0.45-nptl_kernel-4.9/mips-linux-uclibc/bin/mips-linux-uclibc-gcc -march=34kc -mtune=34kc -msoft-float -Ofast -pipe -Wa,--trap -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Wl,-I/usr/lib/freetz/ld-uClibc.so.1 -shared -o my_function.so -fPIC my_function.c

• Execution (device):

./hello_world
Hello world!

• Python testing:

python

import ctypes
so_file = "./my_function.so"
my_library = ctypes.CDLL(so_file)
my_library.square(4)

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