lebr0nli/gep

GEP (GDB Enhanced Prompt) - a GDB plug-in for GDB command prompt with fzf history search, fish-like autosuggestions, tab auto-completion with fzf, partial string matching in history, and more!

Hi there 🖖

I'm an undergraduate computer science student from Taiwan. My most familiar language is Python. I started to play CTF since early 2021, mainly focusing on web challenges, but I also like to solve some pwn and some pyjail/jsjail type challenges :P

I have a small blog written in Chinese here, it is mostly my CTF writeups and some notes.

gep's Issues

Add unit tests

We should find a way to test the features of GEP.

gdb doesn't import prompt_toolkit from $HOME/GEP/

This is a really cool plugin and I'm eager to use its features. However, when I try to load it with source ~/GEP/.gdbinit-gep.py, I get an error about "'_GdbOutputFile' object has no attribute 'fileno'". It looks like there's some issue with prompt_toolkit. To get a full backtrace, I did the following:

(gdb) python
>from prompt_toolkit import PromptSession
>p = PromptSession()
>end
Traceback (most recent call last):
  File "<string>", line 2, in <module>
  File "/home/dp12/.local/lib/python3.8/site-packages/prompt_toolkit/shortcuts/prompt.py", line 468, in __init__
    self.app = self._create_application(editing_mode, erase_when_done)
  File "/home/dp12/.local/lib/python3.8/site-packages/prompt_toolkit/shortcuts/prompt.py", line 719, in _create_application
    application: Application[_T] = Application(
  File "/home/dp12/.local/lib/python3.8/site-packages/prompt_toolkit/application/application.py", line 277, in __init__
    self.output = output or session.output
  File "/home/dp12/.local/lib/python3.8/site-packages/prompt_toolkit/application/current.py", line 70, in output
    self._output = create_output()
  File "/home/dp12/.local/lib/python3.8/site-packages/prompt_toolkit/output/defaults.py", line 77, in create_output
    return Vt100_Output.from_pty(
  File "/home/dp12/.local/lib/python3.8/site-packages/prompt_toolkit/output/vt100.py", line 466, in from_pty
    fd = stdout.fileno()
AttributeError: '_GdbOutputFile' object has no attribute 'fileno'
Error while executing Python code.

Any ideas about what might be happening?

Error when starting gdb

When I installed as instructed in README,

$ bash -c "$(curl -fsSL https://raw.githubusercontent.com/lebr0nli/GEP/main/install.sh)"

I've got this error when starting GDB.

File "~/GEP/.gdbinit-gep.py", line 77
    fzf_cmd = [f"awk '!seen[$0]++' {shlex.quote(HISTORY_FILENAME)}"]
                                                                  ^
SyntaxError: invalid syntax

Add type hints

I was too lazy to add type hints, so the code ended up looking messy.
We might have to consider incorporating mypy into our lint.sh script down the line and adding the missing type hints.

Error in `gdb.prompt_hook` might cause infinite loop

If we set gdb.prompt_hook as following:

x = 0


def foo(current_prompt):
    global x
    if x & 1:
        x += 1
        raise gdb.error("err")
    x += 1
    return "(test) "


gdb.prompt_hook = foo

GEP will step into an infinite loop after the first prompt.

fzf completion is incorrect when I set breakpoint at runtime

Hello,

First, thanks for making this simple yet awesome tool! :D

Here's the bug description:

When I set breakpoint after I run the program, the fzf tab auto-completion for symbol name encounters weird behavior.

For example, if I type B then press <tab>, the first character of each symbol name is overwritten as B.

See the following screenshot. The function name foo::B::func() is displayed as Boo::B::func(). Thus, if I press enter for completion, it will fill the name as Boo::B::func().

It seems that GEP has some problem with searching non-prefix string.

Here's the source.cpp:

#include <iostream>
using namespace std;

namespace foo {
class B {
  public:
    void func()
    {
        cout << "B:func" << endl;
    }
};
}
int main()
{
    foo::B b;
    b.func();
    return 0;
}

Here's my system info:

Ubuntu 20.04 (WSL 1) with all packages installed from APT
g++ (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0
GNU gdb (Ubuntu 9.2-0ubuntu1~20.04.1) 9.2
Python 3.8.10

Please note that the above example is very simple. I don't if this problem occurs BEFORE I run the program.

somthing was wrong with layout src

Hi, thank you for the convenience brought by this tool to my debugging experience. It is really useful!
I find something was wrong when gdb run "layout [src|asm|}regs|split|next|prev]". The specific problems are described below.

When I typed "n", the pane of src was broken, and gdb exited when I continue typing "n", the following is the screenshot

The Operator system is Ubuntu 20.04.6 TLS
The version of gdb is 9.2

thanks

`ctrl-c` is not working when debugging kernel with qemu-system

Somehow, when I'm trying to debug the linux kernel with qemu-system, I can't use ctrl-c to halt it.

With vanilla gdb, ctrl-c works without any issue.

Update the demo on `README.md`

GEP/README.md

Line 3 in 43286bb

[](https://asciinema.org/a/TJiEkHv3cqieR0XizG41uOg93)

The demo on README.md is a little bit outdated, we need an update for it.

Problem with completion popup text

I was trying out this plugin (really cool btw) and I think there is a problem with the completion:

For example:

The rho)) prefix is off.

pwndbg's venv issue

In the latest pwndbg, it used venv to load its dependencies and removed all site-packages's import path.
This causes GEP to fail to load the dependency: prompt_toolkit.
To fix this, we need to create venv for GEP as well or somehow install prompt_toolkit into pwndbg's venv.
I think creating venv probably it's a better idea.

multi-line command hangs GDB

When you input a multi-line GDB command (e.g. while), GEP hangs and CPU usage increases to 100%.

In normal GDB, the result should be:

It may not be a serious problem since I don't use multi-line commands very often. But it indeed hangs and crashes GDB.