Use proper pseudo-tty's instead of pipes when using subprocess

This change avoids the "tcgetattr: Invalid argument" error by making sure the ssh we start does have a proper pseudo-tty.

We could also check whether our current terminal is a proper terminal (by doing a tcgetattr ourselves) but I don't think this adds anything.

This closes #1662 (if all use-cases have been tested: sudo, passwd)

lib/ansible/runner/connection_plugins/ssh.py

@@ -99,8 +99,17 @@ class Connection(object):
             ssh_cmd.append(cmd)
 
         vvv("EXEC %s" % ssh_cmd, host=self.host)
-        p = subprocess.Popen(ssh_cmd, stdin=subprocess.PIPE,
-                             stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+        try:
+            # Make sure stdin is a proper (pseudo) pty to avoid: tcgetattr errors
+            import pty
+            master, slave = pty.openpty()
+            p = subprocess.Popen(ssh_cmd, stdin=slave,
+                                 stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+            stdin = os.fdopen(master, 'w', 0)
+        except:
+            p = subprocess.Popen(ssh_cmd, stdin=subprocess.PIPE,
+                                 stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+            stdin = p.stdin
 
         self._send_password()
 
@@ -118,7 +127,7 @@ class Connection(object):
                 else:
                     stdout = p.communicate()
                     raise errors.AnsibleError('ssh connection error waiting for sudo password prompt')
-            p.stdin.write(self.runner.sudo_pass + '\n')
+            stdin.write(self.runner.sudo_pass + '\n')
             fcntl.fcntl(p.stdout, fcntl.F_SETFL, fcntl.fcntl(p.stdout, fcntl.F_GETFL) & ~os.O_NONBLOCK)
 
         # We can't use p.communicate here because the ControlMaster may have stdout open as well
@@ -133,7 +142,7 @@ class Connection(object):
                     break
             elif p.poll() is not None:
                 break
-        p.stdin.close()  # close stdin after we read from stdout (see also issue #848)
+        stdin.close() # close stdin after we read from stdout (see also issue #848)
 
         if p.returncode != 0 and stdout.find('Bad configuration option: ControlPersist') != -1:
             raise errors.AnsibleError('using -c ssh on certain older ssh versions may not support ControlPersist, set ANSIBLE_SSH_ARGS="" (or ansible_ssh_args in the config file) before running again')