GDB script to workaround issues with GDB debugging in Qt Creator

.qtcreator-gdb-attach-fix.py

#!/usr/bin/python
#
# GDB python script for silly QtCreator, when it used to run debug sessions
# with attaching to running process or remote gdb server.
#
# It automatically fixes following issues:
# - there are no way to allow automatic loading of .gdbinit/python scripts supplied with binary
#   in a safe and/or convinient manner, i.e. without disabling safe-load option and/or
#   playing with safe-load paths in ~/.gdbinit
#   (you may see warning from gdb in debugger console)
# - execution automatically continued after connecting to remote gdb target,
#   as a result you can't do some early preparations
#   (e.g. insert breakpoints in everyting that runs before 'main')
# - other resctrictions because of cwd leaves default (user home)
#
# Using:
# Just add 'source /path/to/this_script' to "Additional Startup Commands"
# in "Options..."->"Debugger"->"GDB" tab.
# When attaching to process, if directory with binary contains file named '<binary_name>.debugpath',
# then its content being read as full path and if it's valid, then it set as current working directory.
# Setting cwd also implies loading scripts from it rather than from binary location, which adds support of '.gdbinit' also.
#
# Reqirements for attach to gdb target:
#  'readelf' must be installed
#
# TODO: respect auto-load parameter (it may be off)

import gdb
import os.path
import subprocess

log_prefix = __file__ + ": "

def add_program_to_autoloadsafepath(exec_binary_path):
    gdb.execute("add-auto-load-safe-path " + os.path.dirname(exec_binary_path))

def load_program_scripts(exec_binary_path):
    global log_prefix
    absdirpath = os.path.dirname(exec_binary_path) + "/"
    reldirpath = absdirpath
    if (os.path.isfile(exec_binary_path + ".debugpath")):
        with open(exec_binary_path + ".debugpath", 'r') as f_debugpath:
            debugpath = f_debugpath.read().replace('\n', '')
            if (os.path.isdir(debugpath)):
                gdb.write(log_prefix + " auto changing cwd to '" + debugpath + "'\n")
                gdb.execute("cd " + debugpath)
                absdirpath = debugpath + "/"
                reldirpath = ""
                if (os.path.isfile(absdirpath + ".gdbinit")):
                    gdb.write(log_prefix + " auto loading '.gdbinit'\n")
                    gdb.execute("source .gdbinit")
    debug_bin_path = absdirpath + os.path.basename(exec_binary_path)
    script_path = reldirpath + os.path.basename(exec_binary_path)
    if (os.path.isfile(debug_bin_path + "-gdb.gdb")):
        script_path += "-gdb.gdb"
    elif (os.path.isfile(debug_bin_path + "-gdb.py")):
        script_path += "-gdb.py"
    elif (os.path.isfile(debug_bin_path + "-gdb.scm")):
        script_path += "-gdb.scm"
    else:
        return
    gdb.write(log_prefix + " auto loading '" + script_path + "'\n")
    gdb.execute("source " + script_path)

def set_pause_on_entry(exec_binary_path):
    entry_point_address = subprocess.check_output('readelf -h ' + exec_binary_path + ' | sed -n \'s/\ *Entry point.*\:\ *//p\' | tr -d \'\n\'', shell=True).decode()
    gdb.Breakpoint("*"+entry_point_address, internal=True)

def event_handler_new_objfile(event):
    global log_prefix
    # Assuming this event fired only for executable binary,
    # which expected to be loaded first.
    # Disable event for other object files, which may potentially be loaded later
    gdb.events.new_objfile.disconnect(event_handler_new_objfile)
    exec_binary_path = event.new_objfile.filename
    add_program_to_autoloadsafepath(exec_binary_path)
    if (gdb.selected_inferior().was_attached):
        # Attaching to running process:
        # Here it's too late to fix-up auto-loading scripts,
        # because by default cwd is user home.
        # So let's just emulate necessary steps ourselves, but with differences
        load_program_scripts(exec_binary_path)
    else:
        # Attaching to remote gdb target:
        # Don't let program start execution
        set_pause_on_entry(exec_binary_path)

gdb.write(log_prefix + " loaded\n")
gdb.events.new_objfile.connect(event_handler_new_objfile)