(C) SSH Remote Shell

Demonstrates how to start a shell on a remote SSH server, run a command, and retrieve the output.

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#include <C_CkSsh.h>

void ChilkatSample(void)
    {
    HCkSsh ssh;
    const char *hostname;
    int port;
    BOOL success;
    int channelNum;
    const char *termType;
    int widthInChars;
    int heightInChars;
    int pixWidth;
    int pixHeight;
    int n;
    int pollTimeoutMs;
    const char *cmdOutput;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    ssh = CkSsh_Create();

    // Hostname may be an IP address or hostname:
    hostname = "www.some-ssh-server.com";
    port = 22;

    // Connect to an SSH server:
    success = CkSsh_Connect(ssh,hostname,port);
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    // Wait a max of 5 seconds when reading responses..
    CkSsh_putIdleTimeoutMs(ssh,5000);

    // Authenticate using login/password:
    success = CkSsh_AuthenticatePw(ssh,"myLogin","myPassword");
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    // Open a session channel.  (It is possible to have multiple
    // session channels open simultaneously.)

    channelNum = CkSsh_OpenSessionChannel(ssh);
    if (channelNum < 0) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    // Some SSH servers require a pseudo-terminal
    // If so, include the call to SendReqPty.  If not, then 
    // comment out the call to SendReqPty.
    // Note: The 2nd argument of SendReqPty is the terminal type,
    // which should be something like "xterm", "vt100", "dumb", etc.
    // A "dumb" terminal is one that cannot process escape sequences.
    // Smart terminals, such as "xterm", "vt100", etc. process
    // escape sequences.  If you select a type of smart terminal,
    // your application will receive these escape sequences
    // included in the command's output.  Use "dumb" if you do not
    // want to receive escape sequences.  (Assuming your SSH
    // server recognizes "dumb" as a standard dumb terminal.)
    termType = "dumb";
    widthInChars = 120;
    heightInChars = 40;
    // Use 0 for pixWidth and pixHeight when the dimensions
    // are set in number-of-chars.
    pixWidth = 0;
    pixHeight = 0;
    success = CkSsh_SendReqPty(ssh,channelNum,termType,widthInChars,heightInChars,pixWidth,pixHeight);
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    // Start a shell on the channel:
    success = CkSsh_SendReqShell(ssh,channelNum);
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    // Start a command in the remote shell.  This example
    // will send a "ls" command to retrieve the directory listing.
    success = CkSsh_ChannelSendString(ssh,channelNum,"ls\r\n","ansi");
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    // Send an EOF.  This tells the server that no more data will 
    // be sent on this channel.  The channel remains open, and
    // the SSH client may still receive output on this channel.
    success = CkSsh_ChannelSendEof(ssh,channelNum);
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    // Read whatever output may already be available on the
    // SSH connection.  ChannelReadAndPoll returns the number of bytes
    // that are available in the channel's internal buffer that
    // are ready to be "picked up" by calling GetReceivedText
    // or GetReceivedData.
    // A return value of -1 indicates failure.
    // A return value of -2 indicates a failure via timeout.

    // The ChannelReadAndPoll method waits
    // for data to arrive on the connection usingi the IdleTimeoutMs
    // property setting.  Once the first data arrives, it continues
    // reading but instead uses the pollTimeoutMs passed in the 2nd argument:
    // A return value of -2 indicates a timeout where no data is received.

    pollTimeoutMs = 2000;
    n = CkSsh_ChannelReadAndPoll(ssh,channelNum,pollTimeoutMs);
    if (n < 0) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    // Close the channel:
    success = CkSsh_ChannelSendClose(ssh,channelNum);
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    // Perhaps we did not receive all of the commands output.
    // To make sure,  call ChannelReceiveToClose to accumulate any remaining
    // output until the server's corresponding "channel close" is received.
    success = CkSsh_ChannelReceiveToClose(ssh,channelNum);
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    // Let's pickup the accumulated output of the command:
    cmdOutput = CkSsh_getReceivedText(ssh,channelNum,"ansi");
    if (CkSsh_getLastMethodSuccess(ssh) != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    // Display the remote shell's command output:
    printf("%s\n",cmdOutput);

    // Disconnect
    CkSsh_Disconnect(ssh);


    CkSsh_Dispose(ssh);

    }