[Python-checkins] gh-90473: WASI requires proper open(2) flags (GH-93529)

[tiran]

https://github.com/python/cpython/commit/4c71d22c4f9fdde6f2234e7dc6a862419cd6fd98
commit: 4c71d22c4f9fdde6f2234e7dc6a862419cd6fd98
branch: main
author: Christian Heimes <christian at python.org>
committer: tiran <christian at python.org>
date: 2022-06-06T12:08:07+02:00
summary:

gh-90473: WASI requires proper open(2) flags (GH-93529)

files:
M Lib/test/support/os_helper.py
M Lib/test/test_os.py
M Tools/wasm/README.md

diff --git a/Lib/test/support/os_helper.py b/Lib/test/support/os_helper.py
index 5d787f16b69dd..a6ec1cfa25ebe 100644
--- a/Lib/test/support/os_helper.py
+++ b/Lib/test/support/os_helper.py
@@ -463,7 +463,10 @@ def create_empty_file(filename):
 def open_dir_fd(path):
     """Open a file descriptor to a directory."""
     assert os.path.isdir(path)
-    dir_fd = os.open(path, os.O_RDONLY)
+    flags = os.O_RDONLY
+    if hasattr(os, "O_DIRECTORY"):
+        flags |= os.O_DIRECTORY
+    dir_fd = os.open(path, flags)
     try:
         yield dir_fd
     finally:
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index f304c5e01e5fa..c0321dcdcc071 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -3993,7 +3993,7 @@ class PathTConverterTests(unittest.TestCase):
         ('access', False, (os.F_OK,), None),
         ('chflags', False, (0,), None),
         ('lchflags', False, (0,), None),
-        ('open', False, (0,), getattr(os, 'close', None)),
+        ('open', False, (os.O_RDONLY,), getattr(os, 'close', None)),
     ]
 
     def test_path_t_converter(self):
@@ -4365,6 +4365,7 @@ def test_fd(self):
                     st = os.stat(entry.name, dir_fd=fd, follow_symlinks=False)
                     self.assertEqual(entry.stat(follow_symlinks=False), st)
 
+    @unittest.skipIf(support.is_wasi, "WASI maps '' to cwd")
     def test_empty_path(self):
         self.assertRaises(FileNotFoundError, os.scandir, '')
 
diff --git a/Tools/wasm/README.md b/Tools/wasm/README.md
index 6bb9bd9978402..3b7a7aecc33ea 100644
--- a/Tools/wasm/README.md
+++ b/Tools/wasm/README.md
@@ -235,6 +235,9 @@ are:
   call read/write/accept on a file descriptor that is passed into the process.
 - ``socket.gethostname()`` and host name resolution APIs like
   ``socket.gethostbyname()`` are not implemented and always fail.
+- ``open(2)`` checks flags more strictly. Caller must pass either
+  ``O_RDONLY``, ``O_RDWR``, or ``O_WDONLY`` to ``os.open``. Directory file
+  descriptors must be created with flags ``O_RDONLY | O_DIRECTORY``.
 - ``chmod(2)`` is not available. It's not possible to modify file permissions,
   yet. A future version of WASI may provide a limited ``set_permissions`` API.
 - User/group related features like ``os.chown()``, ``os.getuid``, etc. are