Libguestfs - Mar 2017 - [PATCH] python: check return value of Python APIs

Addressing issue #1406906.

When constructing the returned objects, check the return value of
Python APIs.

This is especially relevant when dealing with non UTF-8 strings.

A RuntimeError will be raised on failure pointing to the problematic
entry and the field name.

Signed-off-by: Matteo Cafasso <noxdafox@gmail.com>
---
 generator/python.ml | 143 +++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 97 insertions(+), 46 deletions(-)

diff --git a/generator/python.ml b/generator/python.ml
index 11dc48102..d03275276 100644
--- a/generator/python.ml
+++ b/generator/python.ml
@@ -152,12 +152,20 @@ and generate_python_structs ()      pr "PyObject
*\n";
     pr "guestfs_int_py_put_%s_list (struct guestfs_%s_list *%ss)\n"
typ typ typ;
     pr "{\n";
-    pr "  PyObject *list;\n";
+    pr "  PyObject *list, *element;\n";
     pr "  size_t i;\n";
     pr "\n";
     pr "  list = PyList_New (%ss->len);\n" typ;
-    pr "  for (i = 0; i < %ss->len; ++i)\n" typ;
-    pr "    PyList_SetItem (list, i, guestfs_int_py_put_%s
(&%ss->val[i]));\n" typ typ;
+    pr "  if (list == NULL)\n";
+    pr "    PyErr_SetString (PyExc_RuntimeError,
\"PyList_New\");\n";
+    pr "    return NULL;\n";
+    pr "  }\n";
+    pr "  for (i = 0; i < %ss->len; ++i) {\n" typ;
+    pr "    element = guestfs_int_py_put_%s (&%ss->val[i]);\n"
typ typ;
+    pr "    if (element == NULL)\n";
+    pr "      return NULL;\n";
+    pr "    PyList_SetItem (list, i, element);\n";
+    pr "  }\n";
     pr "  return list;\n";
     pr "};\n";
     pr "#endif\n";
@@ -171,73 +179,112 @@ and generate_python_structs ()        pr "PyObject
*\n";
       pr "guestfs_int_py_put_%s (struct guestfs_%s *%s)\n" typ typ
typ;
       pr "{\n";
-      pr "  PyObject *dict;\n";
+      pr "  PyObject *dict, *value;\n";
       pr "\n";
       pr "  dict = PyDict_New ();\n";
+      pr "  if (dict == NULL) {\n";
+      pr "    PyErr_SetString (PyExc_RuntimeError,
\"PyDict_New\");\n";
+      pr "    return NULL;\n";
+      pr "  }\n";
       List.iter (
         function
         | name, FString ->
-            pr "  PyDict_SetItemString (dict, \"%s\",\n"
name;
             pr "#ifdef HAVE_PYSTRING_ASSTRING\n";
-            pr "                        PyString_FromString
(%s->%s));\n"
-              typ name;
+            pr "  value = PyString_FromString (%s->%s);\n" typ
name;
             pr "#else\n";
-            pr "                        PyUnicode_FromString
(%s->%s));\n"
-              typ name;
-            pr "#endif\n"
+            pr "  value = PyUnicode_FromString (%s->%s);\n" typ
name;
+            pr "#endif\n";
+            pr "  if (value == NULL) {\n";
+            pr "    PyErr_SetString (PyExc_RuntimeError,\n";
+            pr "                     \"Error setting
%s.%s\");\n" typ name;
+            pr "    return NULL;\n";
+            pr "  }\n";
+            pr "  PyDict_SetItemString (dict, \"%s\",
value);\n" name;
         | name, FBuffer ->
-            pr "  PyDict_SetItemString (dict, \"%s\",\n"
name;
             pr "#ifdef HAVE_PYSTRING_ASSTRING\n";
-            pr "                        PyString_FromStringAndSize
(%s->%s, %s->%s_len));\n"
+            pr "  value = PyString_FromStringAndSize (%s->%s,
%s->%s_len);\n"
               typ name typ name;
             pr "#else\n";
-            pr "                        PyBytes_FromStringAndSize
(%s->%s, %s->%s_len));\n"
+            pr "  value = PyBytes_FromStringAndSize (%s->%s,
%s->%s_len);\n"
               typ name typ name;
-            pr "#endif\n"
+            pr "#endif\n";
+            pr "  if (value == NULL) {\n";
+            pr "    PyErr_SetString (PyExc_RuntimeError,\n";
+            pr "                     \"Error setting
%s.%s\");\n" typ name;
+            pr "    return NULL;\n";
+            pr "  }\n";
+            pr "  PyDict_SetItemString (dict, \"%s\",
value);\n" name;
         | name, FUUID ->
-            pr "  PyDict_SetItemString (dict, \"%s\",\n"
name;
             pr "#ifdef HAVE_PYSTRING_ASSTRING\n";
-            pr "                        PyString_FromStringAndSize
(%s->%s, 32));\n"
-              typ name;
+            pr "  value = PyString_FromStringAndSize (%s->%s,
32);\n" typ name;
             pr "#else\n";
-            pr "                        PyBytes_FromStringAndSize
(%s->%s, 32));\n"
-              typ name;
-            pr "#endif\n"
+            pr "  value = PyBytes_FromStringAndSize (%s->%s,
32);\n" typ name;
+            pr "#endif\n";
+            pr "  if (value == NULL) {\n";
+            pr "    PyErr_SetString (PyExc_RuntimeError,\n";
+            pr "                     \"Error setting
%s.%s\");\n" typ name;
+            pr "    return NULL;\n";
+            pr "  }\n";
+            pr "  PyDict_SetItemString (dict, \"%s\",
value);\n" name;
         | name, (FBytes|FUInt64) ->
-            pr "  PyDict_SetItemString (dict, \"%s\",\n"
name;
-            pr "                        PyLong_FromUnsignedLongLong
(%s->%s));\n"
-              typ name
+            pr "  value = PyLong_FromUnsignedLongLong (%s->%s);\n"
typ name;
+            pr "  if (value == NULL) {\n";
+            pr "    PyErr_SetString (PyExc_RuntimeError,\n";
+            pr "                     \"Error setting
%s.%s\");\n" typ name;
+            pr "    return NULL;\n";
+            pr "  }\n";
+            pr "  PyDict_SetItemString (dict, \"%s\",
value);\n" name;
         | name, FInt64 ->
-            pr "  PyDict_SetItemString (dict, \"%s\",\n"
name;
-            pr "                        PyLong_FromLongLong
(%s->%s));\n"
-              typ name
+            pr "  value = PyLong_FromLongLong (%s->%s);\n" typ
name;
+            pr "  if (value == NULL) {\n";
+            pr "    PyErr_SetString (PyExc_RuntimeError,\n";
+            pr "                     \"Error setting
%s.%s\");\n" typ name;
+            pr "    return NULL;\n";
+            pr "  }\n";
+            pr "  PyDict_SetItemString (dict, \"%s\",
value);\n" name;
         | name, FUInt32 ->
-            pr "  PyDict_SetItemString (dict, \"%s\",\n"
name;
-            pr "                        PyLong_FromUnsignedLong
(%s->%s));\n"
-              typ name
+            pr "  value = PyLong_FromUnsignedLong (%s->%s);\n" typ
name;
+            pr "  if (value == NULL) {\n";
+            pr "    PyErr_SetString (PyExc_RuntimeError,\n";
+            pr "                     \"Error setting
%s.%s\");\n" typ name;
+            pr "    return NULL;\n";
+            pr "  }\n";
+            pr "  PyDict_SetItemString (dict, \"%s\",
value);\n" name;
         | name, FInt32 ->
-            pr "  PyDict_SetItemString (dict, \"%s\",\n"
name;
-            pr "                        PyLong_FromLong
(%s->%s));\n"
-              typ name
+            pr "  value = PyLong_FromLong (%s->%s);\n" typ name;
+            pr "  if (value == NULL) {\n";
+            pr "    PyErr_SetString (PyExc_RuntimeError,\n";
+            pr "                     \"Error setting
%s.%s\");\n" typ name;
+            pr "    return NULL;\n";
+            pr "  }\n";
+            pr "  PyDict_SetItemString (dict, \"%s\",
value);\n" name;
         | name, FOptPercent ->
-            pr "  if (%s->%s >= 0)\n" typ name;
-            pr "    PyDict_SetItemString (dict, \"%s\",\n"
name;
-            pr "                          PyFloat_FromDouble ((double)
%s->%s));\n"
-              typ name;
+            pr "  if (%s->%s >= 0) {\n" typ name;
+            pr "    value = PyFloat_FromDouble ((double)
%s->%s);\n" typ name;
+            pr "    if (value == NULL) {\n";
+            pr "      PyErr_SetString (PyExc_RuntimeError,\n";
+            pr "                       \"Error setting
%s.%s\");\n" typ name;
+            pr "      return NULL;\n";
+            pr "    }\n";
+            pr "    PyDict_SetItemString (dict, \"%s\",
value);\n" name;
+            pr "  }\n";
             pr "  else {\n";
             pr "    Py_INCREF (Py_None);\n";
             pr "    PyDict_SetItemString (dict, \"%s\",
Py_None);\n" name;
             pr "  }\n"
         | name, FChar ->
             pr "#ifdef HAVE_PYSTRING_ASSTRING\n";
-            pr "  PyDict_SetItemString (dict, \"%s\",\n"
name;
-            pr "                        PyString_FromStringAndSize
(&%s->%s, 1));\n"
-              typ name;
+            pr "  value = PyString_FromStringAndSize (&%s->%s,
1);\n" typ name;
             pr "#else\n";
-            pr "  PyDict_SetItemString (dict, \"%s\",\n"
name;
-            pr "                        PyUnicode_FromStringAndSize
(&%s->%s, 1));\n"
+            pr "  value = PyUnicode_FromStringAndSize (&%s->%s,
1);\n"
               typ name;
-            pr "#endif\n"
+            pr "#endif\n";
+            pr "  if (value == NULL) {\n";
+            pr "    PyErr_SetString (PyExc_RuntimeError,\n";
+            pr "                     \"Error setting
%s.%s\");\n" typ name;
+            pr "    return NULL;\n";
+            pr "  }\n";
+            pr "  PyDict_SetItemString (dict, \"%s\",
value);\n" name;
       ) cols;
       pr "  return dict;\n";
       pr "};\n";
@@ -517,16 +564,20 @@ and generate_python_actions actions ()             pr
"  if (py_r == NULL) goto out;\n";
        | RStringList _ ->
            pr "  py_r = guestfs_int_py_put_string_list (r);\n";
-           pr "  guestfs_int_free_string_list (r);\n"
+           pr "  guestfs_int_free_string_list (r);\n";
+           pr "  if (py_r == NULL) goto out;\n";
        | RStruct (_, typ) ->
            pr "  py_r = guestfs_int_py_put_%s (r);\n" typ;
-           pr "  guestfs_free_%s (r);\n" typ
+           pr "  guestfs_free_%s (r);\n" typ;
+           pr "  if (py_r == NULL) goto out;\n";
        | RStructList (_, typ) ->
            pr "  py_r = guestfs_int_py_put_%s_list (r);\n" typ;
-           pr "  guestfs_free_%s_list (r);\n" typ
+           pr "  guestfs_free_%s_list (r);\n" typ;
+           pr "  if (py_r == NULL) goto out;\n";
        | RHashtable n ->
            pr "  py_r = guestfs_int_py_put_table (r);\n";
-           pr "  guestfs_int_free_string_list (r);\n"
+           pr "  guestfs_int_free_string_list (r);\n";
+           pr "  if (py_r == NULL) goto out;\n";
        | RBufferOut _ ->
            pr "#ifdef HAVE_PYSTRING_ASSTRING\n";
            pr "  py_r = PyString_FromStringAndSize (r, size);\n";
--
2.11.0