[Python-checkins] bpo-32890, os: Use errno instead of GetLastError() in execve() and truncate() (GH-5784)

[Miss Islington (bot)]

https://github.com/python/cpython/commit/8f53dcdb246a3acb0e64b742c35b5f785bd19092
commit: 8f53dcdb246a3acb0e64b742c35b5f785bd19092
branch: 3.7
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2018-10-19T17:46:25-07:00
summary:

bpo-32890, os: Use errno instead of GetLastError() in execve() and truncate() (GH-5784)


path_error() uses GetLastError() on Windows, but some os functions
are implemented via CRT APIs which report errors via errno.
This may result in raising OSError with invalid error code (such
as zero).

Introduce posix_path_error() function and use it where appropriate.
(cherry picked from commit 834603112e6ca35944dd21105b01fca562dc3241)

Co-authored-by: Alexey Izbyshev <izbyshev at ispras.ru>

files:
A Misc/NEWS.d/next/Windows/2018-03-08-20-02-38.bpo-32890.3jzFzY.rst
M Lib/test/test_os.py
M Modules/posixmodule.c

diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index cef4a09d7de9..098d1d44fa35 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -1589,6 +1589,16 @@ def test_execve_invalid_env(self):
         with self.assertRaises(ValueError):
             os.execve(args[0], args, newenv)
 
+    @unittest.skipUnless(sys.platform == "win32", "Win32-specific test")
+    def test_execve_with_empty_path(self):
+        # bpo-32890: Check GetLastError() misuse
+        try:
+            os.execve('', ['arg'], {})
+        except OSError as e:
+            self.assertTrue(e.winerror is None or e.winerror != 0)
+        else:
+            self.fail('No OSError raised')
+
 
 @unittest.skipUnless(sys.platform == "win32", "Win32 specific tests")
 class Win32ErrorTests(unittest.TestCase):
diff --git a/Misc/NEWS.d/next/Windows/2018-03-08-20-02-38.bpo-32890.3jzFzY.rst b/Misc/NEWS.d/next/Windows/2018-03-08-20-02-38.bpo-32890.3jzFzY.rst
new file mode 100644
index 000000000000..e8a63b334192
--- /dev/null
+++ b/Misc/NEWS.d/next/Windows/2018-03-08-20-02-38.bpo-32890.3jzFzY.rst
@@ -0,0 +1,2 @@
+Fix usage of GetLastError() instead of errno in os.execve() and
+os.truncate().
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index bbbff1eca8ff..0c48a66a64dd 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -1421,6 +1421,12 @@ win32_error_object(const char* function, PyObject* filename)
 
 #endif /* MS_WINDOWS */
 
+static PyObject *
+posix_path_object_error(PyObject *path)
+{
+    return PyErr_SetFromErrnoWithFilenameObject(PyExc_OSError, path);
+}
+
 static PyObject *
 path_object_error(PyObject *path)
 {
@@ -1428,7 +1434,7 @@ path_object_error(PyObject *path)
     return PyErr_SetExcFromWindowsErrWithFilenameObject(
                 PyExc_OSError, 0, path);
 #else
-    return PyErr_SetFromErrnoWithFilenameObject(PyExc_OSError, path);
+    return posix_path_object_error(path);
 #endif
 }
 
@@ -1449,6 +1455,12 @@ path_error(path_t *path)
     return path_object_error(path->object);
 }
 
+static PyObject *
+posix_path_error(path_t *path)
+{
+    return posix_path_object_error(path->object);
+}
+
 static PyObject *
 path_error2(path_t *path, path_t *path2)
 {
@@ -5097,7 +5109,7 @@ os_execve_impl(PyObject *module, path_t *path, PyObject *argv, PyObject *env)
 
     /* If we get here it's definitely an error */
 
-    path_error(path);
+    posix_path_error(path);
 
     free_string_array(envlist, envc);
   fail:
@@ -9060,7 +9072,7 @@ os_truncate_impl(PyObject *module, path_t *path, Py_off_t length)
     _Py_END_SUPPRESS_IPH
     Py_END_ALLOW_THREADS
     if (result < 0)
-        return path_error(path);
+        return posix_path_error(path);
 
     Py_RETURN_NONE;
 }