Re: process crash when a plpython function returns unicode

On Wed, Jun 15, 2005 at 02:29:27PM +0200, Zac wrote:

> if you define a plpythonu function that returns a unicode python string
> the server process crashes calling that function.

The crash happens if the Unicode string has the high bit set. For
example, u'\x7f' doesn't cause a crash, but u'\x80' does. Here's
a stack trace from HEAD and Python 2.4.1:

#0 0xfec6967c in PyString_AsString (op=0x0) at Objects/stringobject.c:698
#1 0xfed76a38 in PLy_function_handler (fcinfo=0xffbfde28, proc=0x47c610)
at plpython.c:777
#2 0xfed77df4 in plpython_call_handler (fcinfo=0xffbfde28) at plpython.c:352

Lines 776-77 in plpython.c are:

plrv_so = PyObject_Str(plrv);
plrv_sc = PyString_AsString(plrv_so);

PyObject_Str() is documented to return NULL on failure:

http://www.python.org/doc/2.4.1/api/object.html

Apparently PyString_AsString() isn't expecting a NULL argument, so
the code should probably check the return value of PyObject_Str()
before calling PyString_AsString().

--
Michael Fuhr
http://www.fuhr.org/~mfuhr/