Xojo Plugin

Get the Exit Status of a Remote SSH Command

Demonstrates the Chilkat Ssh.GetChannelExitStatus method, which returns the remote process exit status for a channel. The only argument is the channel number. Call it only after ChannelReceivedExitStatus returns true.

Background: The exit status is how you learn whether a remote command actually succeeded — recall that a successful exec request only means the request was accepted. By Unix convention 0 means success and any nonzero value indicates a failure. Retrieve it promptly after the receive operation and before calling unrelated SSH methods or releasing the channel, since the completed channel record can be discarded.

Chilkat Xojo Plugin Downloads

Download Chilkat for Xojo Plugin

Xojo Plugin

Dim success As Boolean
success = False

//  Demonstrates the Ssh.GetChannelExitStatus method, which returns the remote process exit
//  status for a channel.  The only argument is the channel number.  Call it only after
//  ChannelReceivedExitStatus returns 1.

Dim ssh As New Chilkat.Ssh

Dim sshPort As Int32
sshPort = 22
success = ssh.Connect("ssh.example.com",sshPort)
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
Dim password As String
password = "mySshPassword"

success = ssh.AuthenticatePw("mySshLogin",password)
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

Dim channelNum As Int32
channelNum = ssh.OpenSessionChannel()
If (channelNum < 0) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

success = ssh.SendReqExec(channelNum,"grep -q root /etc/passwd")
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

//  IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
//  it, this call waits forever if the server never sends channel close.
ssh.ReadTimeoutMs = 15000

success = ssh.ChannelReceiveToClose(channelNum)
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

//  Retrieve the exit status immediately, before calling unrelated SSH methods or releasing the
//  channel, because the completed channel record can be discarded.
If (ssh.ChannelReceivedExitStatus(channelNum)) Then
    Dim exitStatus As Int32
    exitStatus = ssh.GetChannelExitStatus(channelNum)
    System.DebugLog("Exit status: " + Str(exitStatus))

    //  By convention, 0 means the remote command succeeded.
    If (exitStatus = 0) Then
        System.DebugLog("The remote command succeeded.")
    Else
        System.DebugLog("The remote command reported a failure.")
    End If

End If

ssh.Disconnect