Another GDB stub implemented in Python3

Setup

# Install and compile urjtag (for Microwatt)
apt install libusb-1.0-0-dev libftdi1-dev python3-dev
git clone -b ftdi-arty https://github.com/shingarov/urjtag.git
cd urjtag/urjtag
PYTHON=python3 ./configure --enable-python --without-ftd2xx
make -j$(nproc)
cd ../..

# Clone this repository
git clone https://github.com/janvrany/pygdbstub.git
cd pygdbstub

# Create virtual environment for pygdbstub
virtualenv --prompt "pygdbstub" .venv
echo "export LD_LIBRARY_PATH=$(realpath ../urjtag/urjtag/src/.libs)" >> .venv/bin/activate
source .venv/bin/activate

# Install dependencies
pip3 install -r requirements-dev.txt
pip3 install ../urjtag/urjtag/bindings/python

# Setup pre-commit and pre-push hooks (if you want)
pre-commit install -t pre-commit
pre-commit install -t pre-push

Usage examples

Using TCP port

.venv/bin/python -m pygdbstub -t microwatt -b Genesys2 -p 7000

• run pygdbstub (-m pygdbstub)
• connect to Microwatt on Digilent Genesys2 FPGA boatd (-t microwatt -b Genesys2)
• listen on localhost, port 7000 (-p 7000)

Then in GDB, connect to stub like:

(gdb) set arch powerpc:common64
(gdb) target remote :7000

Starting pygdbstub directly from GDB

(gdb) set arch powerpc:common64
(gdb) target remote | .venv/bin/python -m pygdbstub -t microwatt

• run pygdbstub (-m pygdbstub)
• connect to Microwatt on Arty FPGA (-t microwatt, Arty is default board for Microwatt target)
• use stdio to communicate with GDB (default)

For developers

Running tests

To run tests, just run:

pytest

Debugging communication

Some hints to help debugging communication between GDB and pygdbstub:

• In GDB, turn on remote protocol debugging:

  set debug remote 1
  

• If you really want to see the exact bytes going back and forth, run stub using socat:

  socat -v tcp4-listen:7007,reuseaddr,fork 'exec:python3 -m pygdbstub'
  

  and then in GDB, connect to port 7007:

  target remote :7007