Forbid an empty argument list in execv call.

Fixes issue 1039.

Lib/test/test_os.py

@@ -441,6 +441,9 @@ class ExecTests(unittest.TestCase):
     def test_execvpe_with_bad_program(self):
         self.assertRaises(OSError, os.execvpe, 'no such app-', [], None)
 
+    def test_execvpe_with_bad_arglist(self):
+        self.assertRaises(ValueError, os.execvpe, 'notepad', [], None)
+
 class Win32ErrorTests(unittest.TestCase):
     def test_rename(self):
         self.assertRaises(WindowsError, os.rename, test_support.TESTFN, test_support.TESTFN+".bak")

Modules/posixmodule.c

@@ -2834,6 +2834,11 @@ posix_execv(PyObject *self, PyObject *args)
                 PyMem_Free(path);
 		return NULL;
 	}
+	if (argc < 1) {
+		PyErr_SetString(PyExc_ValueError, "execv() arg 2 must not be empty");
+                PyMem_Free(path);
+		return NULL;
+	}
 
 	argvlist = PyMem_NEW(char *, argc+1);
 	if (argvlist == NULL) {