[lnst] SshUtils: Fix hanging slaves when using -e option

[Jiří Pírko]

commit 7b9d4e51f4c4b309328e5a62a96be8dd8698af11
Author: Radek Pazdera 
Date:   Thu Apr 5 17:17:40 2012 +0200

SshUtils: Fix hanging slaves when using -e option

This patch fixes problem with haning processes on slave machines,
    after remote test execution using the -e option of nettestctl.py.

The problem is, when `ssh' is killed on the client side, the
    corresponding remote `sshd' is terminated, but it doesn't signal
    bash with SIGHUP if there's no tty allocated. Which (in this case
    leaves two processes hanging on the slave machine (/bin/sh and
    ./nettestslave.py).

The solution here is passing -t agrument to `ssh', which results
    in forced allocation of pseudo-tty. There's one issue with this
    solution: when the remotely executed command finishes, `ssh'
    terminates the connection which reults in printing "Connection
    closed by remote host" even if everything was ok (return code 0).

So I also had to remove the error check associated with this
    message. But I tested this and it still works fine, because
    if the connection is closed by error, `ssh' exits with 255,
    LNST can recognize that and still report it as an error.

Signed-off-by: Radek Pazdera

Common/SshUtils.py |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/Common/SshUtils.py b/Common/SshUtils.py
index 109af71..e306976 100644
--- a/Common/SshUtils.py
+++ b/Common/SshUtils.py
@@ -142,7 +142,8 @@ def _remote_login(session, username, password, prompt, timeout=10):
                         msg = "Got username prompt after password prompt"
                     raise LoginAuthenticationError(msg, text)
             elif match == 3:  # "Connection closed"
-                raise LoginError("Client said 'connection closed'", text)
+                logging.log(logging.INFO, "Remote command execution successful")
+                break
             elif match == 4:  # "Connection refused"
                 raise LoginError("Client said 'connection refused'", text)
             elif match == 5:  # "Please wait"
@@ -183,7 +184,7 @@ def remote_login(host, port, username, password, prompt, linesep="\n",
         command = ""
     else:
         command = "-C '%s'" % (command)
-    cmd = ("ssh -o ServerAliveInterval=5 -o ServerAliveCountMax=2 -o UserKnownHostsFile=/dev/null "
+    cmd = ("ssh -t -o ServerAliveInterval=5 -o ServerAliveCountMax=2 -o UserKnownHostsFile=/dev/null "
            "-p %s %s@%s %s" % #-o PreferredAuthentications=password
            (port, username, host, command))