subp: Fix subp usage with non-ascii characters when no system locale.

If python starts up without a locale set, then its default encoding
ends up set as ascii.  That is not easily changed with the likes of
setlocale.  In order to avoid UnicodeDecodeErrors cloud-init will
encode to bytes a python3 string or python2 basestring so that the
values passed to Popen are already bytes.

LP: #1751051

1 files changed, 6 insertions, 1 deletions

diff --git a/cloudinit/util.py b/cloudinit/util.py
index 338fb971..5a919cfe 100644
--- a/cloudinit/util.py
+++ b/cloudinit/util.py
@@ -1865,8 +1865,13 @@ def subp(args, data=None, rcs=None, env=None, capture=True, shell=False,
         if not isinstance(data, bytes):
             data = data.encode()
 
+    # Popen converts entries in the arguments array from non-bytes to bytes.
+    # When locale is unset it may use ascii for that encoding which can
+    # cause UnicodeDecodeErrors. (LP: #1751051)
+    bytes_args = [x if isinstance(x, six.binary_type) else x.encode("utf-8")
+                  for x in args]
     try:
-        sp = subprocess.Popen(args, stdout=stdout,
+        sp = subprocess.Popen(bytes_args, stdout=stdout,
                               stderr=stderr, stdin=stdin,
                               env=env, shell=shell)
         (out, err) = sp.communicate(data)