raise ZombieProcess instead of AccessDenied if process is a zombielinux-zombie-proc

4 files changed, 44 insertions, 3 deletions

diff --git a/HISTORY.rst b/HISTORY.rst
index e9833990..b742cd8d 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -1,5 +1,16 @@
 *Bug tracker at https://github.com/giampaolo/psutil/issues*
 
+5.9.4 (IN DEVELOPMENT)
+======================
+
+XXXX-XX-XX
+
+**Bug fixes**
+
+- XXXX_, [Linux]: when process is a zombie, certain methods like
+  `Process.open_files()`_, `Process.environ()`_ and `Process.io_counters
+  ()`_ erroneously raise ``AccessDenied`` instead of ``ZombieProcess``.
+
 5.9.3
 =====
 
diff --git a/psutil/__init__.py b/psutil/__init__.py
index ca2d9273..56742791 100644
--- a/psutil/__init__.py
+++ b/psutil/__init__.py
@@ -211,7 +211,7 @@ if hasattr(_psplatform.Process, "rlimit"):
 AF_LINK = _psplatform.AF_LINK
 
 __author__ = "Giampaolo Rodola'"
-__version__ = "5.9.3"
+__version__ = "5.9.4"
 version_info = tuple([int(num) for num in __version__.split('.')])
 
 _timer = getattr(time, 'monotonic', time.time)
diff --git a/psutil/_pslinux.py b/psutil/_pslinux.py
index 9dc9643a..c16db892 100644
--- a/psutil/_pslinux.py
+++ b/psutil/_pslinux.py
@@ -1635,6 +1635,20 @@ def ppid_map():
     return ret
 
 
+def is_zombie(pid):
+    try:
+        data = bcat("%s/%s/stat" % (get_procfs_path(), pid))
+    except EnvironmentError:
+        return False
+    else:
+        # Process name is between parentheses. It can contain spaces and
+        # other parentheses. This is taken into account by looking for
+        # the first occurrence of "(" and the last occurrence of ")".
+        rpar = data.rfind(b')')
+        fields = data[rpar + 2:].split()
+        return fields[0] == "Z"
+
+
 def wrap_exceptions(fun):
     """Decorator which translates bare OSError and IOError exceptions
     into NoSuchProcess and AccessDenied.
@@ -1644,9 +1658,19 @@ def wrap_exceptions(fun):
         try:
             return fun(self, *args, **kwargs)
         except PermissionError:
-            raise AccessDenied(self.pid, self._name)
+            # Linux is peculiar in that accessing certain pseudo files
+            # like /proc/pid/fd/*, /proc/pid/environ and /proc/pid/io
+            # results in EPERM if process is a zombie. In such cases it
+            # appears more correct to raise ZP instead of AD.
+            if is_zombie(self.pid):
+                raise ZombieProcess(self.pid, self._name, self._ppid)
+            else:
+                raise AccessDenied(self.pid, self._name)
         except ProcessLookupError:
-            raise NoSuchProcess(self.pid, self._name)
+            if is_zombie(self.pid):
+                raise ZombieProcess(self.pid, self._name, self._ppid)
+            else:
+                raise NoSuchProcess(self.pid, self._name)
         except FileNotFoundError:
             if not os.path.exists("%s/%s" % (self._procfs_path, self.pid)):
                 raise NoSuchProcess(self.pid, self._name)
diff --git a/psutil/tests/test_process.py b/psutil/tests/test_process.py
index 26869e98..bd31ac66 100755
--- a/psutil/tests/test_process.py
+++ b/psutil/tests/test_process.py
@@ -1324,6 +1324,12 @@ class TestProcess(PsutilTestCase):
         for fun, name in ns.iter(ns.all):
             succeed_or_zombie_p_exc(fun)
 
+        if LINUX:
+            # TODO: broken
+            # self.assertRaises(psutil.ZombieProcess, zproc.exe)
+            self.assertRaises(psutil.ZombieProcess, zproc.cwd)
+            self.assertRaises(psutil.ZombieProcess, zproc.memory_full_info)
+
         assert psutil.pid_exists(zproc.pid)
         self.assertIn(zproc.pid, psutil.pids())
         self.assertIn(zproc.pid, [x.pid for x in psutil.process_iter()])