How to highlight and color gdb output during interactive debugging?

Question

Please don't reply I should use ddd, nemiver, emacs, vim, or any other front-end, I just prefer gdb as it is, but would like to see its output with some terminal colors.

Answer 1

.gdbinit

You can tweak your ~/.gdbinit to have colors. You can use mammon's .gdbinit which is available here:

https://github.com/gdbinit/gdbinit

You can tweak it as much as you want too. I found this thanks to this SO answer. Here's the kind of output that you can obtain:

A GitHub repository is also available: https://github.com/gdbinit/Gdbinit

On a side note, the same idea was also applied to lldb.

GDB Dashboard

Following the same concept, GDB Dashboard provides a modular visual interface for GDB in Python.

(void)walker

Another similar project uses GDB's Python support to provide more extensibility, so this is worth checking out: https://github.com/dholm/voidwalker

@dholm also provides his own .gdbinit inspired from the previous one.

pwndbg

Some projects provide a set of useful functions, including improved display. This is the case for PEDA or pwndbg. The latter gives the following description:

A PEDA replacement. In the spirit of our good friend windbg, pwndbg is pronounced pwnd-bag.

• Speed
• Resiliency
• Clean code

It provides commands to support debugging and exploit development similar to the ones from PEDA, and better display (although this is not the main focus of the project). The software is still under development, and has not been properly released yet.

voltron

The project description states:

Voltron is an extensible debugger UI for hackers. It allows you to attach utility views running in other terminals to your debugger (LLDB or GDB), displaying helpful information such as disassembly, stack contents, register values, etc, while still giving you the same debugger CLI you're used to.

You can modify your .gdbinit to automatically integrate it. However, the display itself is outside of GDB (e.g. in a tmux split).

GEF

GEF is another option, and it is described as:

It is aimed to be used mostly by exploiters and reverse-engineers, to provide additional features to GDB using the Python API to assist during the process of dynamic analysis and exploit development.

Answer 2

It's not colours, but consider gdb's text gui. It makes a vast difference to how usable gdb is.

You can launch it with:

gdb -tui executable.out

Screenshot:

As you can see, the main features are:

• shows what line of the source we are on and surrounding lines
• shows breakpoints

Answer 3

I know you did not want a frontend. But how about cgdb it is very close to gdb, it is textmode but has a source window above with syntax highlight on the code.

Answer 4

It is possible to greatly enhance the appears of gdb through the use of colors. This is done via any of the following methods:

1. Colorized prompt via the "set prompt". E.g., make the prompt bold and red:

   set prompt \033[1;31m(gdb) \033[m

   or make the prompt a new shape, bold and red:

   set prompt \033[01;31m\n\n#####################################> \033[0m

   

2. Colorized commands via hooks

3. Colorized syntax highlighting of the "list" command.

All examples are available at the following blog posts written by Michael Kelleher:

"Beautify GDB", May 12, 2010 (via archive.org)

"Experimental GDB syntax highlighting", May 15, 2010 (via archive.org)

Answer 5

New in upcoming GDB 8.3!

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=blob;f=gdb/NEWS

Terminal styling is now available for the CLI and the TUI. GNU Source Highlight can additionally be used to provide styling of source code snippets. See the "set style" commands, below, for more information.

Answer 6

cgdb is much better than gdb -tui

Answer 7

#into .gdbinit
shell mkfifo /tmp/colorPipe

define hook-disassemble
echo \n
shell cat /tmp/colorPipe | c++filt | highlight --syntax=asm -s darkness -Oxterm256 &
set logging redirect on
set logging on /tmp/colorPipe
end 

define hookpost-disassemble
hookpost-list
end 

define hook-list
echo \n
shell cat /tmp/colorPipe | c++filt | highlight --syntax=cpp -s darkness -Oxterm256 &
set logging redirect on
set logging on /tmp/colorPipe
end 

define hookpost-list
set logging off 
set logging redirect off 
shell sleep 0.1s
end 

define hook-quit
shell rm /tmp/colorPipe
end 

define re
hookpost-disassemble
echo \033[0m
end 
document re
Restore colorscheme
end 

Warning: Buggy. No TUI support, 'user-mode' hack.

Found the main part here and modified it a bit. Needs highlight, c++filt. If colors get messed up issue re command.

Answer 8

Neat, I just found this hack using colout: https://github.com/nojhan/colout/blob/master/colout/example.gdbinit

Answer 9

I wanted to highlight as follows: emphasise the lines of a stack trace which belong to my source files (rather than libraries).

The solution was to use gdb-python (on MSYS; on Linux typically gdb comes with Python built-in already?), hook backtrace, use

python stack_trace = gdb.execute('backtrace', False, True')

Then process stack_trace with Python's regexes, and print them out. Bold and other colours are achieved by a function like this:

def term_style(*v):
    """1 is bold, 30--37 are the 8 colours, but specifying bold may also
    change the colour. 40--47 are background colours."""
    return '\x1B['+';'.join(map(str, v))+'m'

#Use like this:
print term_style(1) + 'This will be bold' + term_style(0) #Reset.
print term_style(1,30) + 'This will be bold and coloured' + term_style(0)
print term_style(1,30,40) + 'Plus coloured background' + term_style(0)

Answer 10

Another good combination of colors is given by this configuration. It renders inspecting the backtraces a lot easier. To use it, just save that file as ~/.gdbinit and run gdb normally

Answer 11

you can get whatever colors you want;

# gdb
(gdb) shell echo -en '\E[47;34m'"\033[1m"
...
anything is now blue foreground and white background
...
(gdb) shell tput sgr0
... back to normal