[ Patch to 7.4.X.]

In several places PL/Python was calling PyObject_Str() and then
PyString_AsString() without checking if the former had returned
NULL to indicate an error.  PyString_AsString() doesn't expect a
NULL argument, so passing one causes a segmentation fault.  This
patch adds checks for NULL and raises errors via PLy_elog(), which
prints details of the underlying Python exception.  The patch also
adds regression tests for these checks.  All tests pass on my
Solaris 9 box running HEAD and Python 2.4.1.

diff --git a/src/pl/plpython/plpython.c b/src/pl/plpython/plpython.c
index 332927013a5ef3502806d00f1b81e76db1ecafb0..80b60a4777fe248cd5e51b45c65dc56455ee1c03 100644 (file)
--- a/src/pl/plpython/plpython.c
+++ b/src/pl/plpython/plpython.c
@@ -29,7 +29,7 @@
  * MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
  * IDENTIFICATION
- *     $Header: /cvsroot/pgsql/src/pl/plpython/plpython.c,v 1.41.2.1 2004/01/04 00:14:55 momjian Exp $
+ *     $Header: /cvsroot/pgsql/src/pl/plpython/plpython.c,v 1.41.2.2 2005/09/25 03:18:16 momjian Exp $
  *
  *********************************************************************
  */
@@ -561,6 +561,8 @@ PLy_modify_tuple(PLyProcedure * proc, PyObject * pltd, TriggerData *tdata,
                if (plval != Py_None && !tupdesc->attrs[atti]->attisdropped)
                {
                        plstr = PyObject_Str(plval);
+                       if (!plstr)
+                               PLy_elog(ERROR, "function \"%s\" could not modify tuple", proc->proname);
                        src = PyString_AsString(plstr);
 
                        modvalues[i] = FunctionCall3(&proc->result.out.r.atts[atti].typfunc,
@@ -847,6 +849,8 @@ PLy_function_handler(FunctionCallInfo fcinfo, PLyProcedure * proc)
        {
                fcinfo->isnull = false;
                plrv_so = PyObject_Str(plrv);
+               if (!plrv_so)
+                       PLy_elog(ERROR, "function \"%s\" could not create return value", proc->proname);
                plrv_sc = PyString_AsString(plrv_so);
                rv = FunctionCall3(&proc->result.out.d.typfunc,
                                                   PointerGetDatum(plrv_sc),
@@ -2117,7 +2121,9 @@ PLy_spi_execute_plan(PyObject * ob, PyObject * list, int limit)
                char       *sv;
 
                PyObject   *so = PyObject_Str(list);
-
+               if (!so)
+                       PLy_elog(ERROR, "function \"%s\" could not execute plan",
+                                                       PLy_procedure_name(PLy_last_procedure));
                sv = PyString_AsString(so);
                PLy_exception_set(PLy_exc_spi_error,
                                                  "Expected sequence of %d arguments, got %d. %s",
@@ -2166,6 +2172,9 @@ PLy_spi_execute_plan(PyObject * ob, PyObject * list, int limit)
                        if (elem != Py_None)
                        {
                                so = PyObject_Str(elem);
+                               if (!so)
+                                       PLy_elog(ERROR, "function \"%s\" could not execute plan",
+                                                                       PLy_procedure_name(PLy_last_procedure));
                                sv = PyString_AsString(so);
 
                                /*
@@ -2693,7 +2702,13 @@ PLy_traceback(int *xlevel)
        else
                vstr = "Unknown";
 
-       estr = PyString_AsString(eob);
+       /*
+        * I'm not sure what to do if eob is NULL here -- we can't call
+        * PLy_elog because that function calls us, so we could end up
+        * with infinite recursion.  I'm not even sure if eob could be
+        * NULL here -- would an Assert() be more appropriate?
+        */
+       estr = eob ? PyString_AsString(eob) : "Unknown Exception";
        xstr = PLy_printf("%s: %s", estr, vstr);
 
        Py_DECREF(eob);