Backpatch to 8.0.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 ff584f077dd85ae7ec96f69d1600f5ebf39ad9ee..acd9ce216bfda2520b5d40f7df24ee59b533238a 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
- * $PostgreSQL: pgsql/src/pl/plpython/plpython.c,v 1.58.4.1 2005/03/24 17:22:44 tgl Exp $
+ * $PostgreSQL: pgsql/src/pl/plpython/plpython.c,v 1.58.4.2 2005/09/23 21:02:37 momjian Exp $
  *
  *********************************************************************
  */
@@ -516,6 +516,8 @@ 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,
@@ -773,6 +775,8 @@ 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),
@@ -2018,7 +2022,9 @@ 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_curr_procedure));
        sv = PyString_AsString(so);
        PLy_exception_set(PLy_exc_spi_error,
                          "Expected sequence of %d arguments, got %d. %s",
@@ -2043,6 +2049,9 @@ 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_curr_procedure));
                sv = PyString_AsString(so);
 
                /*
@@ -2530,7 +2539,13 @@ 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);