x-terminal-emulator gdb.attach not working properly

[cnitlrt]

pwntools version

Name: pwntools
Version: 4.12.0
Summary: Pwntools CTF framework and exploit development library.
Home-page: 
Author: 
Author-email: "Gallopsled et al." <pwntools-users@googlegroups.com>
License: Mostly MIT, some GPL/BSD, see LICENSE-pwntools.txt
Location: /home/ubuntu/.local/lib/python3.8/site-packages
Requires: capstone, colored-traceback, intervaltree, mako, packaging, paramiko, pip, psutil, pyelftools, pygments, pyserial, pysocks, python-dateutil, requests, ropgadget, rpyc, six, sortedcontainers, unicorn, unix-ar, zstandard
Required-by: 

Testcase

test.c

//gcc test.c -o test
#include <stdio.h>
#include <string.h>

int main(){
    puts("Hello");
    char buf[0x20];
    read(0,buf,0x20);
    puts("Hello");
    read(0,buf,0x20);
}

exp.py

from pwn import*
context.arch = "amd64"
# context.log_level = "debug"
p = process("./test")
p.recvuntil(b"Hello")
p.send(b"aaaa")
p.recvuntil(b"Hello")
attach(p)
p.send(b"aaaa")
p.interactive()

Debug Output

When I used gdb.attach in x-terminal on ubuntu20.04 to debug, I got an error. I think maybe run_new_terminal returned the wrong gdb_pid so I tried +1 it and found that it worked normally #2363

environ

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.6 LTS
Release:    20.04
Codename:   focal

GNU gdb (Ubuntu 9.2-0ubuntu1~20.04.1) 9.2
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

[peace-maker]

x-terminal-emulator isn't a program on it's own but just a meta placeholder for various terminal emulators. I think this is special to the terminal you're using and should be more strict around that terminal instead of the meta group.

Try update-alternatives --display x-terminal-emulator to see which terminal you're actually using. Maybe it sets some environment variable you could detect?

[cnitlrt]

thank you for your reply,I used the update-alternatives --display x-terminal-emulator command to show that the terminal in use is /usr/bin/gnome-terminal.wrapper

╰─$ update-alternatives --display x-terminal-emulator
x-terminal-emulator - auto mode
  link best version is /usr/bin/gnome-terminal.wrapper
  link currently points to /usr/bin/gnome-terminal.wrapper
  link x-terminal-emulator is /usr/bin/x-terminal-emulator
  slave x-terminal-emulator.1.gz is /usr/share/man/man1/x-terminal-emulator.1.gz
/usr/bin/gnome-terminal.wrapper - priority 40
  slave x-terminal-emulator.1.gz: /usr/share/man/man1/gnome-terminal.1.gz
/usr/bin/koi8rxterm - priority 20
  slave x-terminal-emulator.1.gz: /usr/share/man/man1/koi8rxterm.1.gz
/usr/bin/lxterm - priority 30
  slave x-terminal-emulator.1.gz: /usr/share/man/man1/lxterm.1.gz
/usr/bin/uxterm - priority 20
  slave x-terminal-emulator.1.gz: /usr/share/man/man1/uxterm.1.gz
/usr/bin/xterm - priority 20
  slave x-terminal-emulator.1.gz: /usr/share/man/man1/xterm.1.gz
╭─ubuntu@ubuntu-virtual-machine ~ 
╰─$ update-alternatives --config x-terminal-emulator
There are 5 choices for the alternative x-terminal-emulator (providing /usr/bin/x-terminal-emulator).

  Selection    Path                             Priority   Status
------------------------------------------------------------
* 0            /usr/bin/gnome-terminal.wrapper   40        auto mode
  1            /usr/bin/gnome-terminal.wrapper   40        manual mode
  2            /usr/bin/koi8rxterm               20        manual mode
  3            /usr/bin/lxterm                   30        manual mode
  4            /usr/bin/uxterm                   20        manual mode
  5            /usr/bin/xterm                    20        manual mode

Press <enter> to keep the current choice[*], or type selection number: 

[cnitlrt]

Oh! I maybe understand what you mean. I tried changing it to xterm and found that it can be attached normally.

[cnitlrt]

Hello, I attempted to update the code to match the terminal containing 'gnome-terminal' in the symbolic link name for 'x-terminal', and to increment the PID by 1. Does this seem reasonable? Thank you very much.

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