#!/usr/bin/env python2
#
# Test-case for global symbol contamination bug.
#
# When libGL dlopens the llvmpipe-based swrast driver, it sets RTLD_GLOBAL
# to maintain compatability with third party software (see bug #79469).
# Since LLVM depends on libedit, and swrast depends on LLVM, libedit's symbols
# are loaded as RTLD_GLOBAL.
#
# Libedit is a BSD-licensed reimplementation of GNU readline containing a
# partial readline compatability layer, and hence shares some symbol names
# with the original readline library. Python's readline module uses symbols
# which are not implemented by libedit, causing some symbols to be resolved to
# libedit and others to be resolved to readline, resulting in program
# misbehaviour (e.g. not cleaning up the terminal correctly after termination)
# and semi-random segfaults. As a specific example, rl_initialize is resolved
# to libedit.so if libgl is loaded and libreadline.so if it is not.
#
# This is a variant of bug #93103.
# Tested on Debian Sid with mesa commit 62a819184141133478cfdcfa76b62d5bb7e14fd5

import os
from ctypes import *

# Force use of swrast driver
os.environ['LIBGL_ALWAYS_SOFTWARE'] = "1"

# Get an X Display handle to feed libGL

print "Loading libX11"
libX11 = cdll.LoadLibrary("libX11.so.6")
libX11.XOpenDisplay.argtypes = [c_char_p]
libX11.XOpenDisplay.restype = c_void_p

print "Calling XOpenDisplay(None)"
dpy = libX11.XOpenDisplay(None)

# Trigger libGL to dlopen the driver by calling glXQueryVersion

print "Loading libGL"
libGL = cdll.LoadLibrary("libGL.so.1")
libGL.glXQueryVersion.argtypes = [c_void_p, POINTER(c_bool), POINTER(c_bool)]
libGL.glXQueryVersion.restype = c_bool
print "Calling glXQueryVersion(dpy, None, None)"
success = libGL.glXQueryVersion(dpy, None, None)

# Trigger python to load the readline library

print "Loading readline module"
import readline

# Attempt to use the readline-enhanced raw_input function
raw_input("Input: ")