python-interface.md

Python interface

Python API for GDB. Whenever your script starts getting a little more complex, you will need to use it.

Usage

All scripts are in Python 3.

Each Python file in this directory can be run with:

gdb --batch -x name.py

Some of those files have corresponding C files that must be compiled before running the script. The naming convention for those C files is name_py.c.

Run a python script

You can run a Python script with either -x:

gdb --batch -x name.py

or from inside GDB:

source name.py

The script type is recognized from the file extension.

The interface is not Python only

There seem to be many operations which need execute to be done.

What the API does it to parse the GDB information into Python.

To suppress execute stdout, you will often use:

execute('cmd', to_string=True)

py

python command

Single command:

py print(123)

Multiple lines:

(gdb) py
>print(123)
>end

Scripts can be sourced with:

source script.py

GDB knows that they are Python and not .gdb scripts by the file extension.

python-interactive

pi

Start a Python shell inside GDB:

(gdb) pi
>>> a = 1
>>> print(a)
1

Exit with Ctrl + D.

Bibliography

• help gdb from the python shell. Great way to see what the API contains. Then read the .texi docs for the details.

• https://sourceware.org/gdb/wiki/PythonGdbTutorial 2008 tutorial by the API author. Somewhat outdated.

Libraries that use it:

• https://github.com/longld/peda/
• https://github.com/stephenbradshaw/pygdbdis/blob/master/pygdbdis.py
• https://github.com/jfoote/exploitable