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https://issues.apache.org/jira/browse/SSHD-1085?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17243855#comment-17243855
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Lyor Goldstein commented on SSHD-1085:
--------------------------------------
{quote}
based on your comment, SSHD clientSession cannot detect the channel status? if
the remote sshd server is down or whole server cannot reachable, I think there
must be a way to detect the TCP connection status.
{quote}
I think you are confusing channel +TCP+ status - which depends on whether there
is a viable ongoing connection with channel exit status - which is a
+protocol+ construct. They are distinct "status" though we use the same word.
{quote}
I still dont think throw the NULL
{quote}
I think you are not describing correctly the code flow - our code does not
throw NPE +your+ code does because you are treating an {{Integer}} which the
documentation clearly states that can be null as if it isn't.
{quote}
We also use JSCH with the same reboot command to remote node, JSCH can handle
correctly.
I feel JSCH can handle the channel status more robust, while Mina SSHD has
problem to handle the channel status.
{quote}
I don't really understand your definition of "correctly" - can you clarify what
you think is "correct" and what is "incorrect" ? Can you provide some reference
standard documentation for the definition ?
{quote}
hope when I give follow: EnumSet.of(ClientChannelEvent.CLOSED,
ClientChannelEvent.EXIT_STATUS,ClientChannelEvent.EXIT_SIGNAL,
ClientChannelEvent.EOF) for the mask, so the AbstractClientChannel.waitFor()
will return if found any above status, not only just look for CLOSED.
{quote}
You should get the {{CLOSED}} event but I would be very surprised if you get
any exit status - so check for null and don't assume.
> channel.waitFor() get stuck when run reboot command
> ---------------------------------------------------
>
> Key: SSHD-1085
> URL: https://issues.apache.org/jira/browse/SSHD-1085
> Project: MINA SSHD
> Issue Type: Bug
> Affects Versions: 2.5.1
> Environment: linux
> Reporter: min yun law
> Priority: Minor
>
> Trying to run linux command "reboot" by mina sshd to remote node, the node is
> in reboot, but the ClientChannel object still keep open, not in closed
> status, Here is the logic code in my project:
>
> {code:java}
> String command = "reboot";
> ChannelExec channel = clientSession.createExecChannel(command);
> if(!channel.isClosed())
> {
> ByteArrayOutputStream out = new ByteArrayOutputStream();
> ByteArrayOutputStream err = new ByteArrayOutputStream(); channel.setOut(out);
> channel.setErr(err);
> channel.open().await(); //this passed
> //follow call will cause stuck
> Collection<ClientChannelEvent> waitMask =
> channel.waitFor(REMOTE_COMMAND_WAIT_EVENTS, 0L);
> String outputStr = new String(out.toByteArray(), StandardCharsets.UTF_8);
> //some case this will throw runtime exception
> int exitStatus = channel.getExitStatus();
> }
>
> {code}
>
> So why the ChannelExec cannot get the correct channel status when remote node
> is rebooting?
>
>
>
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