Fix sudo

devlib/host.py

@@ -112,7 +112,7 @@ def execute(self, command, timeout=None, check_exit_code=True,
             if self.unrooted:
                 raise TargetStableError('unrooted')
             password = self._get_password()
-            command = "echo {} | sudo -k -p ' ' -S -- sh -c {}".format(quote(password), quote(command))
+            command = "echo {} | sudo -k -p '' -S -- sh -c {}".format(quote(password), quote(command))
         ignore = None if check_exit_code else 'all'
         try:
             stdout, stderr = check_output(command, shell=True, timeout=timeout, ignore=ignore)
@@ -138,7 +138,7 @@ def background(self, command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, as
             password = self._get_password()
             # The sudo prompt will add a space on stderr, but we cannot filter
             # it out here
-            command = "echo {} | sudo -k -p ' ' -S -- sh -c {}".format(quote(password), quote(command))
+            command = "echo {} | sudo -k -p '' -S -- sh -c {}".format(quote(password), quote(command))
 
         # Make sure to get a new PGID so PopenBackgroundCommand() can kill
         # all sub processes that could be started without troubles.

devlib/target.py

@@ -535,9 +535,17 @@ async def check_connection(self):
         """
         Check that the connection works without obvious issues.
         """
-        out = await self.execute.asyn('true', as_root=False)
-        if out.strip():
-            raise TargetStableError('The shell seems to not be functional and adds content to stderr: {}'.format(out))
+        async def check(**kwargs):
+            out = await self.execute.asyn('true', **kwargs)
+            if out:
+                raise TargetStableError('The shell seems to not be functional and adds content to stderr: {!r}'.format(out))
+
+        await check(as_root=False)
+        # If we are rooted, we usually run with sudo. Unfortunately, PAM
+        # modules can write random text to stdout such as:
+        # Your password will expire in XXX days.
+        if self.is_rooted:
+            await check(as_root=True)
 
     def disconnect(self):
         connections = self._conn.get_all_values()

devlib/utils/ssh.py

@@ -61,7 +61,7 @@
 from devlib.connection import ConnectionBase, ParamikoBackgroundCommand, SSHTransferHandle
 
 
-DEFAULT_SSH_SUDO_COMMAND = "sudo -k -p ' ' -S -- sh -c {}"
+DEFAULT_SSH_SUDO_COMMAND = "sudo -k -p '' -S -- sh -c {}"
 
 
 class _SSHEnv: