Delphi ActiveX

Check Whether an SSH Exit Status Was Received

Demonstrates the Chilkat Ssh.ChannelReceivedExitStatus method, which reports whether the server supplied an exit-status value for a channel. The only argument is the channel number. When it returns true, call GetChannelExitStatus to read the value.

Background: Always test this before reading the exit status, because the server is not required to send one for every channel type or command — treating a missing status as "0" would silently turn a failure into a success. Exit status is independent of EOF and CLOSE: it can arrive after EOF and either before or together with CLOSE.

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var
success: Integer;
ssh: TChilkatSsh;
sshPort: Integer;
password: WideString;
channelNum: Integer;
exitStatus: Integer;

begin
success := 0;

//  Demonstrates the Ssh.ChannelReceivedExitStatus method, which reports whether the server
//  supplied an exit-status value for a channel.  The only argument is the channel number.  When
//  it returns 1, call GetChannelExitStatus to read the value.

ssh := TChilkatSsh.Create(Self);

sshPort := 22;
success := ssh.Connect('ssh.example.com',sshPort);
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

//  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.
password := 'mySshPassword';

success := ssh.AuthenticatePw('mySshLogin',password);
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

channelNum := ssh.OpenSessionChannel();
if (channelNum < 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

success := ssh.SendReqExec(channelNum,'test -f /etc/hosts');
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

//  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 = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

//  The server is not required to send an exit status for every channel type or command.
if (ssh.ChannelReceivedExitStatus(channelNum)) then
  begin
    exitStatus := ssh.GetChannelExitStatus(channelNum);
    Memo1.Lines.Add('Exit status: ' + IntToStr(exitStatus));
  end
else
  begin
    Memo1.Lines.Add('The server did not provide an exit status.');
  end;

ssh.Disconnect();