fix #599 (Windows): process name() can now be determined for all PIDs

HISTORY.rst

@@ -16,6 +16,8 @@ Bug tracker at https://github.com/giampaolo/psutil/issues
 - #589: Process.cpu_affinity() accepts any kind of iterable (set, tuple, ...),
   not only lists.
 - #594: all deprecated APIs were removed.
+- #599: [Windows] process name() can now be determined for all processes even
+  when running as a limited user.
 
 **Bug fixes**
 

psutil/_psutil_windows.c

@@ -662,6 +662,46 @@ psutil_proc_exe(PyObject *self, PyObject *args) {
 }
 
 
+/*
+ * Return process base name.
+ * Note: psutil_proc_exe() is attempted first because it's faster
+ * but it raise AccessDenied for processes owned by other users
+ * in which case we fall back on using this.
+ */
+static PyObject *
+psutil_proc_name(PyObject *self, PyObject *args) {
+    long pid;
+    int ok;
+    PROCESSENTRY32 pentry;
+    HANDLE hSnapShot;
+
+    if (! PyArg_ParseTuple(args, "l", &pid))
+        return NULL;
+    hSnapShot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, pid);
+    if (hSnapShot == INVALID_HANDLE_VALUE) {
+        PyErr_SetFromWindowsErr(0);
+        return NULL;
+    }
+    pentry.dwSize = sizeof(PROCESSENTRY32);
+    ok = Process32First(hSnapShot, &pentry);
+    if (! ok) {
+        PyErr_SetFromWindowsErr(0);
+        return NULL;
+    }
+    while (ok) {
+        if (pentry.th32ProcessID == pid) {
+            CloseHandle(hSnapShot);
+            return Py_BuildValue("s", pentry.szExeFile);
+        }
+        ok = Process32Next(hSnapShot, &pentry);
+    }
+
+    CloseHandle(hSnapShot);
+    NoSuchProcess();
+    return NULL;
+}
+
+
 /*
  * Return process memory information as a Python tuple.
  */
@@ -3198,6 +3238,8 @@ PsutilMethods[] =
      "Return process cmdline as a list of cmdline arguments"},
     {"proc_exe", psutil_proc_exe, METH_VARARGS,
      "Return path of the process executable"},
+    {"proc_name", psutil_proc_name, METH_VARARGS,
+     "Return process name"},
     {"proc_kill", psutil_proc_kill, METH_VARARGS,
      "Kill the process identified by the given PID"},
     {"proc_cpu_times", psutil_proc_cpu_times, METH_VARARGS,

psutil/_psutil_windows.h

@@ -23,6 +23,7 @@ static PyObject* psutil_proc_kill(PyObject* self, PyObject* args);
 static PyObject* psutil_proc_memory_info(PyObject* self, PyObject* args);
 static PyObject* psutil_proc_memory_info_2(PyObject* self, PyObject* args);
 static PyObject* psutil_proc_memory_maps(PyObject* self, PyObject* args);
+static PyObject* psutil_proc_name(PyObject* self, PyObject* args);
 static PyObject* psutil_proc_num_handles(PyObject* self, PyObject* args);
 static PyObject* psutil_proc_open_files(PyObject* self, PyObject* args);
 static PyObject* psutil_proc_priority_get(PyObject* self, PyObject* args);

psutil/_pswindows.py

@@ -284,7 +284,14 @@ def name(self):
         elif self.pid == 4:
             return "System"
         else:
-            return os.path.basename(self.exe())
+            try:
+                # Note: this will fail with AD for most PIDs owned
+                # by another user but it's faster.
+                return os.path.basename(self.exe())
+            except OSError as err:
+                if err.errno in ACCESS_DENIED_SET:
+                    return cext.proc_name(self.pid)
+                raise
 
     @wrap_exceptions
     def exe(self):

test/_windows.py

@@ -370,6 +370,16 @@ def compare_with_tolerance(ret1, ret2, tolerance):
         if failures:
             self.fail('\n\n'.join(failures))
 
+    def test_compare_name_exe(self):
+        for p in psutil.process_iter():
+            try:
+                a = os.path.basename(p.exe())
+                b = p.name()
+            except (psutil.NoSuchProcess, psutil.AccessDenied):
+                pass
+            else:
+                self.assertEqual(a, b)
+
     def test_zombies(self):
         # test that NPS is raised by the 2nd implementation in case a
         # process no longer exists