gh-57187: add xattr support for FreeBSD and macOS

Doc/library/os.rst

@@ -3781,12 +3781,29 @@ features:
    .. versionadded:: 3.10
 
 
-Linux extended attributes
-~~~~~~~~~~~~~~~~~~~~~~~~~
+Extended attributes
+~~~~~~~~~~~~~~~~~~~
 
 .. versionadded:: 3.3
+   Added suppport for Linux.
 
-These functions are all available on Linux only.
+.. versionadded:: 3.12
+   Added support for macOS and FreeBSD.
+
+These functions provide access to file system extended attributes on the Unix
+platforms that support them.
+
+.. note::
+
+   On some platforms, extended attribute names have a *namespace qualifier*
+   prefix such as ``'user.'`` or ``'system.'``.
+
+   On FreeBSD, Python requires that the caller of functions that expect an
+   attribute name specify the namespace qualifier, which is interpreted
+   according to ``extattr_string_to_namespace()``. The rest of the string is
+   interpreted as the attribute name. E.g. Python will interpret the
+   ``'user.mime_type'`` string as the attribute name ``'mime_type'`` in the
+   ``EXTATTR_NAMESPACE_USER`` namespace.
 
 .. function:: getxattr(path, attribute, *, follow_symlinks=True)
 
@@ -3800,9 +3817,13 @@ These functions are all available on Linux only.
 
    .. audit-event:: os.getxattr path,attribute os.getxattr
 
+   .. availability:: Linux, macOS, FreeBSD.
+
    .. versionchanged:: 3.6
       Accepts a :term:`path-like object` for *path* and *attribute*.
 
+   .. versionadded:: 3.12
+      Added support for macOS and FreeBSD.
 
 .. function:: listxattr(path=None, *, follow_symlinks=True)
 
@@ -3814,11 +3835,21 @@ These functions are all available on Linux only.
    This function can support :ref:`specifying a file descriptor <path_fd>` and
    :ref:`not following symlinks <follow_symlinks>`.
 
+   .. note::
+
+      On FreeBSD, this function will only list attributes residing in the
+      ``user`` and ``system`` (if permitted) namespaces, prefixed with a
+      namespace qualifier.
+
    .. audit-event:: os.listxattr path os.listxattr
 
+   .. availability:: Linux, macOS, FreeBSD.
+
    .. versionchanged:: 3.6
       Accepts a :term:`path-like object`.
 
+   .. versionadded:: 3.12
+      Added support for macOS and FreeBSD.
 
 .. function:: removexattr(path, attribute, *, follow_symlinks=True)
 
@@ -3832,9 +3863,13 @@ These functions are all available on Linux only.
 
    .. audit-event:: os.removexattr path,attribute os.removexattr
 
+   .. availability:: Linux, macOS, FreeBSD.
+
    .. versionchanged:: 3.6
       Accepts a :term:`path-like object` for *path* and *attribute*.
 
+   .. versionadded:: 3.12
+      Added support for macOS and FreeBSD.
 
 .. function:: setxattr(path, attribute, value, flags=0, *, follow_symlinks=True)
 
@@ -3857,28 +3892,63 @@ These functions are all available on Linux only.
 
    .. audit-event:: os.setxattr path,attribute,value,flags os.setxattr
 
+   .. availability:: Linux, macOS, FreeBSD.
+
    .. versionchanged:: 3.6
       Accepts a :term:`path-like object` for *path* and *attribute*.
 
+   .. versionadded:: 3.12
+      Added support for macOS and FreeBSD.
 
 .. data:: XATTR_SIZE_MAX
 
    The maximum size the value of an extended attribute can be. Currently, this
-   is 64 KiB on Linux.
+   is 64 KiB.
 
+   .. availability:: Linux.
+
+.. data:: XATTR_NAME_MAX
+
+   The maximum length the name of an extended attribute (including the
+   namespace qualifier) can be. Currently, this is 255 bytes.
+
+   .. availability:: Linux.
+
+   .. versionadded:: 3.12
+
+.. data:: XATTR_MAXNAMELEN
+
+   The maximum length the name of an extended attribute can be. Currently, this
+   is 127 UTF-8 bytes.
+
+   .. availability:: macOS.
+
+   .. versionadded:: 3.12
+
+.. data:: EXTATTR_MAXNAMELEN
+
+   The maximum length the name of an extended attribute (excluding the
+   namespace qualifier) can be. Currently, this is 255 bytes.
+
+   .. availability:: FreeBSD.
+
+   .. versionadded:: 3.12
 
 .. data:: XATTR_CREATE
 
    This is a possible value for the flags argument in :func:`setxattr`. It
    indicates the operation must create an attribute.
 
+   .. availability:: Linux, macOS, FreeBSD.
 
 .. data:: XATTR_REPLACE
 
    This is a possible value for the flags argument in :func:`setxattr`. It
    indicates the operation must replace an existing attribute.
 
 
+   .. availability:: Linux, macOS, FreeBSD.
+
 .. _os-process:
 
 Process Management

Lib/shutil.py

@@ -322,19 +322,23 @@ def _copyxattr(src, dst, *, follow_symlinks=True):
 
         """
 
+        if sys.platform.startswith("freebsd") or sys.platform == "darwin":
+            missing_xattr_errno = errno.ENOATTR
+        else:
+            missing_xattr_errno = errno.ENODATA
         try:
             names = os.listxattr(src, follow_symlinks=follow_symlinks)
         except OSError as e:
-            if e.errno not in (errno.ENOTSUP, errno.ENODATA, errno.EINVAL):
+            if e.errno not in (errno.ENOTSUP, errno.EINVAL):
                 raise
             return
         for name in names:
             try:
                 value = os.getxattr(src, name, follow_symlinks=follow_symlinks)
                 os.setxattr(dst, name, value, follow_symlinks=follow_symlinks)
             except OSError as e:
-                if e.errno not in (errno.EPERM, errno.ENOTSUP, errno.ENODATA,
-                                   errno.EINVAL, errno.EACCES):
+                if e.errno not in (errno.EPERM, errno.ENOTSUP, errno.EINVAL,
+                                   errno.EACCES, missing_xattr_errno):
                     raise
 else:
     def _copyxattr(*args, **kwargs):

Lib/test/test_os.py

@@ -3671,18 +3671,21 @@ def supports_extended_attributes():
 
 @unittest.skipUnless(supports_extended_attributes(),
                      "no non-broken extended attribute support")
-# Kernels < 2.6.39 don't respect setxattr flags.
-@support.requires_linux_version(2, 6, 39)
 class ExtendedAttributeTests(unittest.TestCase):
 
     def _check_xattrs_str(self, s, getxattr, setxattr, removexattr, listxattr, **kwargs):
         fn = os_helper.TESTFN
+        if sys.platform.startswith("freebsd") or sys.platform == "darwin":
+            xattr_errno = errno.ENOATTR
+        else:
+            xattr_errno = errno.ENODATA
+
         self.addCleanup(os_helper.unlink, fn)
         create_file(fn)
 
         with self.assertRaises(OSError) as cm:
             getxattr(fn, s("user.test"), **kwargs)
-        self.assertEqual(cm.exception.errno, errno.ENODATA)
+        self.assertEqual(cm.exception.errno, xattr_errno)
 
         init_xattr = listxattr(fn)
         self.assertIsInstance(init_xattr, list)
@@ -3701,7 +3704,7 @@ def _check_xattrs_str(self, s, getxattr, setxattr, removexattr, listxattr, **kwa
 
         with self.assertRaises(OSError) as cm:
             setxattr(fn, s("user.test2"), b"bye", os.XATTR_REPLACE, **kwargs)
-        self.assertEqual(cm.exception.errno, errno.ENODATA)
+        self.assertEqual(cm.exception.errno, xattr_errno)
 
         setxattr(fn, s("user.test2"), b"foo", os.XATTR_CREATE, **kwargs)
         xattr.add("user.test2")
@@ -3710,7 +3713,7 @@ def _check_xattrs_str(self, s, getxattr, setxattr, removexattr, listxattr, **kwa
 
         with self.assertRaises(OSError) as cm:
             getxattr(fn, s("user.test"), **kwargs)
-        self.assertEqual(cm.exception.errno, errno.ENODATA)
+        self.assertEqual(cm.exception.errno, xattr_errno)
 
         xattr.remove("user.test")
         self.assertEqual(set(listxattr(fn)), xattr)
@@ -3730,14 +3733,23 @@ def _check_xattrs(self, *args, **kwargs):
         self._check_xattrs_str(os.fsencode, *args, **kwargs)
         os_helper.unlink(os_helper.TESTFN)
 
+    # Kernels < 2.6.39 don't respect setxattr flags.
+    @support.requires_linux_version(2, 6, 39)
+    @support.requires_freebsd_version(5)
     def test_simple(self):
         self._check_xattrs(os.getxattr, os.setxattr, os.removexattr,
                            os.listxattr)
 
+    # Kernels < 2.6.39 don't respect setxattr flags.
+    @support.requires_linux_version(2, 6, 39)
+    @support.requires_freebsd_version(5)
     def test_lpath(self):
         self._check_xattrs(os.getxattr, os.setxattr, os.removexattr,
                            os.listxattr, follow_symlinks=False)
 
+    # Kernels < 2.6.39 don't respect setxattr flags.
+    @support.requires_linux_version(2, 6, 39)
+    @support.requires_freebsd_version(5)
     def test_fds(self):
         def getxattr(path, *args):
             with open(path, "rb") as fp:

Lib/test/test_shutil.py

@@ -1091,7 +1091,7 @@ def test_copystat_symlinks(self):
         os.symlink(src, src_link)
         os.symlink(dst, dst_link)
         if hasattr(os, 'lchmod'):
-            os.lchmod(src_link, stat.S_IRWXO)
+            os.lchmod(src_link, stat.S_IRUSR)
         if hasattr(os, 'lchflags') and hasattr(stat, 'UF_NODUMP'):
             os.lchflags(src_link, stat.UF_NODUMP)
         src_link_stat = os.lstat(src_link)

Misc/NEWS.d/next/Library/2018-03-02-23-38-36.bpo-12978.GmUrw4.rst

@@ -0,0 +1 @@
+Add support for extended attributes on FreeBSD