Net ssh users - May 2008 - hanging #exec!

Hi,

I''m occasionally experiencing hangs on Net:SSH:Session#exec!

My setup: I''m using four Linux machines:
1: my testserver which will be executing the Ruby code
2: a gateway (linux router)
3: a linux computer
4: an embedded linux machine (telnet only)

To execute commands on a shell on the linux computer and embedded
linux machine, I use SSH connection and local port forwarding.  While
alternatively executing commands on the embedded machine and the linux
computer, the commands on the linux computer hang.

I noticed that the command in question is actually not send to the
machine, but that the Net:SSH library assumes that it is, and waits
for the return indefinitely.  Using the Net:SSH:Session#exec method
stops the hangs, but then the commands are not executed.

I have the feeling this is a timing issue, maybe I''m using the library
wrongly :(

Code below.

Best regards,

Nicky

--------- used versions:
OS: Ubuntu Fiesty

ruby: 1.8.5
net:ssh: 2.0.1

-------- code:

require ''net/ssh''
require ''net/telnet''
require ''thread''

def test1
    # set up ssh connectoin to the gateway
    puts "starting connection to gateway"
    gw = Net::SSH.start("10.0.0.200",
                        "####",
                        :password => "####")

    # start a ssh tunnel for the ssh connection to the cpe
    puts "starting tunnel to cpe"
    Thread.new do
        gw.forward.local(8022, "192.168.253.38", 22)
        gw.loop {true}
    end

    # set up ssh connection to the cpe
    puts "starting connection to cpe"
    cpe = Net::SSH.start("127.0.0.1",
                         "####",
                         :password => "####",
                         :port => 8022)

    # start a ssh tunnel for the telnet connection to the modem
    puts "starting tunnel to modem"
    Thread.new do
        cpe.forward.local(8023, "192.168.1.1", 23)
        cpe.loop {true}
    end

    # set up a telnet connection to the modem
    puts "starting connection to modem"
    modem = Net::Telnet.new("Host" => "127.0.0.1",
                            "Port" => 8023)
    modem.login("Name"     => "####",
                "Password" => "####")


    command = "uname -a"
    puts "command= " + command
    puts modem.cmd(command)
    puts cpe.exec!(command)

    modem.close
    cpe.forward.cancel_local(8023)

    # start a ssh tunnel for the telnet connection to the modem
    puts "starting tunnel to modem"
    Thread.new do
        cpe.forward.local(8023, "192.168.1.1", 23)
        cpe.loop {true}
    end

    # set up a telnet connection to the modem
    puts "starting connection to modem"
    modem = Net::Telnet.new("Host" => "127.0.0.1",
                            "Port" => 8023)
    modem.login("Name"     => "####",
                "Password" => "####")

    command = "cat /proc/uptime"
    puts "command= " + command
    puts modem.cmd(command)
    puts cpe.exec!(command)

    modem.close
    cpe.forward.cancel_local(8023)

    # start a ssh tunnel for the telnet connection to the modem
    puts "starting tunnel to modem"
    Thread.new do
        cpe.forward.local(8023, "192.168.1.1", 23)
        cpe.loop {true}
    end

    # set up a telnet connection to the modem
    puts "starting connection to modem"
    modem = Net::Telnet.new("Host" => "127.0.0.1",
                            "Port" => 8023)
    modem.login("Name"     => "####",
                "Password" => "####")

    command = "ls -l"
    puts "command= " + command
    puts modem.cmd(command)
    puts cpe.exec!(command)

    # close it all up
    modem.close
    cpe.forward.cancel_local(8023)
    cpe.close
    gw.forward.cancel_local(8022)
    gw.close
end

test1

Hi,

Could it be that when the port forward is cancelled the process loop
is closed too and the command following is effectively halted?

Best regards,

Nicky