#!/bin/sh
#
# print traceback of running python process
#

usage () { # rc
	local rc=$1
	echo "$(basename "$0") <pid_of_python_process>"
	exit "$rc"
}
case "$1" in
-h|--help)
	usage 0
	;;
[1-9]*)
	PYPID="$1"
	;;
*)
	usage 2 >&2
	;;
esac

exe=$(readlink "/proc/$PYPID/exe") || usage 2 >&2
case "$exe" in
/usr/bin/python2.?)
	;;
*)
	echo "Not a python process." >&2
	exit 1
	;;
esac

dbg=/usr/lib/debug$exe
ver=$(basename "$exe")
if ! [ -f "$dbg" ]
then
	echo "Missing Python debug symbols from package $ver-dbg" >&2
	exit 1
fi

tmpfile=$(mktemp)
trap "rm -f '$tmpfile'" EXIT
top="$(objdump -t "$dbg" | sed -ne 's!^[[:xdigit:]]\+[[:space:]].*[[:space:]]0*\([[:xdigit:]]\+\)[[:space:]]\(Py_Main\|t_bootstrap\)!($pc < \2 || $pc >= \2+0x\1) \\\&\\\& !p' | tr -d '\n')(0 < 1)"

gdb=/usr/share/doc/$ver/gdbinit
if [ -f "$gdb" ]
then
	sed -e 's!\$pc < Py_Main || \$pc > Py_[[:graph:]]\+!'"$top"'!' "$gdb" >"$tmpfile"
elif [ -f "$gdb.gz" ]
then
	gzip -dc <"$gdb.gz" | sed -e 's!\$pc < Py_Main || \$pc > Py_[[:graph:]]\+!'"$top"'!' >"$tmpfile"
else
	echo "Missing gdb file: $gdb" >&2
	exit 1
fi

gdb -p "$PYPID" -batch -n -x "$tmpfile" -ex "set pagination off" -ex "thread apply all pystack"