handle the case where Buffer is NULL

3 files changed, 15 insertions, 4 deletions

diff --git a/psutil/_psutil_windows.c b/psutil/_psutil_windows.c
index 7b0f1cce..64b58f4f 100644
--- a/psutil/_psutil_windows.c
+++ b/psutil/_psutil_windows.c
@@ -500,8 +500,14 @@ psutil_proc_exe(PyObject *self, PyObject *args) {
         return NULL;
     }
 
-    py_exe = PyUnicode_FromWideChar(processIdInfo.ImageName.Buffer,
-                                    processIdInfo.ImageName.Length / 2);
+    if (processIdInfo.ImageName.Buffer == NULL) {
+        // Happens for PID 4.
+        py_exe = Py_BuildValue("s", "");
+    }
+    else {
+        py_exe = PyUnicode_FromWideChar(processIdInfo.ImageName.Buffer,
+                                        processIdInfo.ImageName.Length / 2);
+    }
     FREE(buffer);
     return py_exe;
 }
diff --git a/psutil/_pswindows.py b/psutil/_pswindows.py
index 34295f9e..83793c5a 100644
--- a/psutil/_pswindows.py
+++ b/psutil/_pswindows.py
@@ -753,7 +753,11 @@ class Process(object):
     @memoize_when_activated
     def exe(self):
         exe = cext.proc_exe(self.pid)
-        return convert_dos_path(exe)
+        if not PY3:
+            exe = py2_strencode(exe)
+        if exe.startswith('\\'):
+            return convert_dos_path(exe)
+        return exe  # May be "Registry", "MemCompression", ...
 
     @wrap_exceptions
     @retry_error_partial_copy
@@ -839,7 +843,6 @@ class Process(object):
             for addr, perm, path, rss in raw:
                 path = convert_dos_path(path)
                 if not PY3:
-                    assert isinstance(path, unicode), type(path)
                     path = py2_strencode(path)
                 addr = hex(addr)
                 yield (addr, perm, path, rss)
diff --git a/psutil/tests/test_contracts.py b/psutil/tests/test_contracts.py
index bdf055d0..5e258b30 100755
--- a/psutil/tests/test_contracts.py
+++ b/psutil/tests/test_contracts.py
@@ -431,6 +431,8 @@ class TestFetchAllProcesses(unittest.TestCase):
         if not ret:
             self.assertEqual(ret, '')
         else:
+            if WINDOWS and not ret.endswith('.exe'):
+                return  # May be "Registry", "MemCompression", ...
             assert os.path.isabs(ret), ret
             # Note: os.stat() may return False even if the file is there
             # hence we skip the test, see: