(MFC) Using sudo in an SSH Shell Session

Demonstrates how to run a command as sudo in a shell session.

Note: This example requires Chilkat v9.5.0.65 or greater.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkSsh.h>
#include <CkStringBuilder.h>

void ChilkatSample(void)
    {
    CkString strOut;

    // This example assumes Chilkat SSH/SFTP to have been previously unlocked.
    // See Unlock SSH for sample code.

    CkSsh ssh;

    int port = 22;
    bool success = ssh.Connect("the-ssh-server.com",port);
    if (success != true) {
        strOut.append(ssh.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Authenticate using login/password:
    success = ssh.AuthenticatePw("theSshLogin","theSshPassword");
    if (success != true) {
        strOut.append(ssh.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Start a shell session.
    // (The QuickShell method was added in Chilkat v9.5.0.65)
    int channelNum = ssh.QuickShell();
    if (channelNum < 0) {
        strOut.append(ssh.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Construct a StringBuilder with our command ("ls") run with "sudo"
    // Note: The line-endings are potentially important.  Some SSH servers may
    // require either LF or CRLF line endings.  (Unix/Linux/OSX servers typically
    // use bare-LF line endings.  Windows servers likely use CRLF line endings.)

    // Using "sudo -S" causes the sudo prompt to be written to stderr,
    // and the password is read from stdin (i.e. from the echo command ouput).
    // The sudo commands -p option allows us to set the prompt, and we can set it to
    // the empty string, thus eliminating the prompt from the stderr completely.
    // This allows us to run the command as root (super-user) with no prompt.
    CkStringBuilder sbCommands;
    sbCommands.Append("echo \"theSshPassword\" | sudo -S -p \"\" ls\n");

    // Add another command to echo a marker string that
    // we'll use in ChannelReceiveUntilMatch below.
    // The use of single quotes around 'IS' is a trick so that the output
    // of the command is "THIS IS THE END OF THE SCRIPT", but the terminal echo
    // includes the single quotes.  This allows us to read until we see the actual
    // output of the last command.
    sbCommands.Append("echo THIS 'IS' THE END OF THE SCRIPT\n");

    // Send the commands..
    success = ssh.ChannelSendString(channelNum,sbCommands.getAsString(),"ansi");
    if (success != true) {
        strOut.append(ssh.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Send an EOF to indicate no more commands will be sent.
    // For brevity, we're not checking the return values of each method call.
    // Your code should check the success/failure of each call.
    success = ssh.ChannelSendEof(channelNum);

    // Receive output up to our marker.
    success = ssh.ChannelReceiveUntilMatch(channelNum,"THIS IS THE END OF THE SCRIPT","ansi",true);

    // Close the channel.
    // It is important to close the channel only after receiving the desired output.
    success = ssh.ChannelSendClose(channelNum);

    // Get any remaining output..
    success = ssh.ChannelReceiveToClose(channelNum);

    // Get the complete output for all the commands in the session.
    strOut.append("--- output ----");
    strOut.append("\r\n");
    strOut.append(ssh.getReceivedText(channelNum,"ansi"));
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }