Fix failure in listdir when server uses a locale

Fixes #985

SFTPAttributes uses the locale-aware %b directive for the
abbreviated month name with time.strftime, but was not
decoding the result on Python 2.7.

Add a strftime alias in py3compat that will always return
unicode, and resolve the mixing of bytes and text in
SFTPAttributes methods.

Add a test at the listdir level, and a more specific test
for the SFTPAttributes asbytes method.

3 files changed, 51 insertions, 12 deletions

diff --git a/paramiko/py3compat.py b/paramiko/py3compat.py
index 0f80e19f..0330abac 100644
--- a/paramiko/py3compat.py
+++ b/paramiko/py3compat.py
@@ -1,5 +1,6 @@
-import sys
 import base64
+import sys
+import time
 
 __all__ = [
     "BytesIO",
@@ -29,6 +30,9 @@ __all__ = [
 PY2 = sys.version_info[0] < 3
 
 if PY2:
+    import __builtin__ as builtins
+    import locale
+
     string_types = basestring  # NOQA
     text_type = unicode  # NOQA
     bytes_types = str
@@ -39,7 +43,10 @@ if PY2:
     decodebytes = base64.decodestring
     encodebytes = base64.encodestring
 
-    import __builtin__ as builtins
+    def bytestring(s):  # NOQA
+        if isinstance(s, unicode):  # NOQA
+            return s.encode('utf-8')
+        return s
 
     byte_ord = ord  # NOQA
     byte_chr = chr  # NOQA
@@ -100,6 +107,11 @@ if PY2:
         # 64-bit
         MAXSIZE = int((1 << 63) - 1)  # NOQA
     del X
+
+    def strftime(format, t):
+        """Same as time.strftime but returns unicode."""
+        _, encoding = locale.getlocale(locale.LC_TIME)
+        return time.strftime(format, t).decode(encoding or 'ascii')
 else:
     import collections
     import struct
@@ -167,3 +179,5 @@ else:
     next = next
 
     MAXSIZE = sys.maxsize  # NOQA
+
+    strftime = time.strftime    # NOQA
diff --git a/paramiko/sftp_attr.py b/paramiko/sftp_attr.py
index f16ac746..1ad16349 100644
--- a/paramiko/sftp_attr.py
+++ b/paramiko/sftp_attr.py
@@ -19,7 +19,7 @@
 import stat
 import time
 from paramiko.common import x80000000, o700, o70, xffffffff
-from paramiko.py3compat import long, b
+from paramiko.py3compat import long, PY2, strftime
 
 
 class SFTPAttributes(object):
@@ -169,7 +169,7 @@ class SFTPAttributes(object):
             out += "-xSs"[suid + (n & 1)]
         return out
 
-    def __str__(self):
+    def _as_text(self):
         """create a unix-style long description of the file (like ls -l)"""
         if self.st_mode is not None:
             kind = stat.S_IFMT(self.st_mode)
@@ -205,16 +205,13 @@ class SFTPAttributes(object):
             # shouldn't really happen
             datestr = "(unknown date)"
         else:
+            time_tuple = time.localtime(self.st_mtime)
             if abs(time.time() - self.st_mtime) > 15552000:
                 # (15552000 = 6 months)
-                datestr = time.strftime(
-                    "%d %b %Y", time.localtime(self.st_mtime)
-                )
+                datestr = strftime('%d %b %Y', time_tuple)
             else:
-                datestr = time.strftime(
-                    "%d %b %H:%M", time.localtime(self.st_mtime)
-                )
-        filename = getattr(self, "filename", "?")
+                datestr = strftime('%d %b %H:%M', time_tuple)
+        filename = getattr(self, 'filename', '?')
 
         # not all servers support uid/gid
         uid = self.st_uid
@@ -240,4 +237,10 @@ class SFTPAttributes(object):
         )
 
     def asbytes(self):
-        return b(str(self))
+        return self._as_text().encode('utf-8')
+
+    if PY2:
+        __unicode__ = _as_text
+        __str__ = asbytes
+    else:
+        __str__ = _as_text
diff --git a/tests/test_sftp.py b/tests/test_sftp.py
index a98a46c6..84c5252b 100644
--- a/tests/test_sftp.py
+++ b/tests/test_sftp.py
@@ -34,6 +34,11 @@ import pytest
 
 from paramiko.py3compat import PY2, b, u, StringIO
 from paramiko.common import o777, o600, o666, o644
+from tests import requireNonAsciiLocale, skipUnlessBuiltin
+from tests.stub_sftp import StubServer, StubSFTPServer
+from tests.loop import LoopSocket
+from tests.util import test_path
+import paramiko.util
 from paramiko.sftp_attr import SFTPAttributes
 
 from .util import needs_builtin
@@ -270,6 +275,16 @@ class TestSFTP(object):
             sftp.remove(sftp.FOLDER + "/fish.txt")
             sftp.remove(sftp.FOLDER + "/tertiary.py")
 
+    @requireNonAsciiLocale()
+    def test_listdir_in_locale(self):
+        """Test listdir under a locale that uses non-ascii text."""
+        sftp.open(FOLDER + '/canard.txt', 'w').close()
+        try:
+            folder_contents = sftp.listdir(FOLDER)
+            self.assertEqual(['canard.txt'], folder_contents)
+        finally:
+            sftp.remove(FOLDER + '/canard.txt')
+
     def test_setstat(self, sftp):
         """
         verify that the setstat functions (chown, chmod, utime, truncate) work.
@@ -781,6 +796,13 @@ class TestSFTP(object):
         finally:
             sftp.remove("%s/nonutf8data" % sftp.FOLDER)
 
+    @requireNonAsciiLocale('LC_TIME')
+    def test_sftp_attributes_locale_time(self):
+        """Test SFTPAttributes under a locale with non-ascii time strings."""
+        some_stat = os.stat(sftp.FOLDER)
+        sftp_attributes = SFTPAttributes.from_stat(some_stat, u('a_directory'))
+        self.assertTrue(b'a_directory' in sftp_attributes.asbytes())
+
     def test_sftp_attributes_empty_str(self, sftp):
         sftp_attributes = SFTPAttributes()
         assert (