SSH to a Cisco Switch - Processing "More" Responses

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Demonstrates connecting to a Cisco switch, entering privileged mode with the ena command, and running a command whose response is paged. Each page ends with --More-- and requires a SPACE character to request the next page.

Note: QuickShell allocates a PTY, which is what a network device console expects. The device presents an interactive prompt, and each command's output is read up to the next prompt.

#include <C_CkSsh.h>
#include <C_CkStringArray.h>
#include <C_CkStringBuilder.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSsh ssh;
    int port;
    const char *password;
    int channelNum;
    BOOL caseSensitive;
    const char *received;
    const char *enablePassword;
    HCkStringArray saMatch;
    HCkStringBuilder sbReceived;
    BOOL moreComing;
    const char *pageText;

    success = FALSE;

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

    //  Demonstrates connecting to a Cisco switch, entering privileged mode, and running a command
    //  whose response is paged -- each page ends with "--More--" and requires a SPACE character to
    //  request the next page.

    ssh = CkSsh_Create();

    port = 22;
    success = CkSsh_Connect(ssh,"172.16.16.100",port);
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    //  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 = CkSsh_AuthenticatePw(ssh,"mySshLogin",password);
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

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

    //  IMPORTANT: Set a read timeout before receiving until a match.  ReadTimeoutMs defaults to 0,
    //  which means no limit -- without it, this call waits forever if the received data never
    //  contains a match.
    CkSsh_putReadTimeoutMs(ssh,15000);

    caseSensitive = TRUE;

    //  In unprivileged mode the switch prompt ends with ">".
    success = CkSsh_ChannelReceiveUntilMatch(ssh,channelNum,">","utf-8",caseSensitive);
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    received = CkSsh_getReceivedText(ssh,channelNum,"utf-8");
    if (CkSsh_getLastMethodSuccess(ssh) == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    printf("%s\n",received);

    //  Send "ena" to enter privileged mode.  Cisco devices expect a bare CR to terminate a command.
    success = CkSsh_ChannelSendString(ssh,channelNum,"ena\r","utf-8");
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    success = CkSsh_ChannelReceiveUntilMatch(ssh,channelNum,"Password:","utf-8",caseSensitive);
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    received = CkSsh_getReceivedText(ssh,channelNum,"utf-8");
    if (CkSsh_getLastMethodSuccess(ssh) == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    printf("%s\n",received);

    //  The enable password is separate from the login password, and likewise should come from a
    //  secure source rather than being hard-coded.
    enablePassword = "myEnablePassword";
    success = CkSsh_ChannelSendString(ssh,channelNum,enablePassword,"utf-8");
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    success = CkSsh_ChannelSendString(ssh,channelNum,"\r","utf-8");
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    //  In privileged mode the prompt ends with "#" instead of ">".
    success = CkSsh_ChannelReceiveUntilMatch(ssh,channelNum,"#","utf-8",caseSensitive);
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    received = CkSsh_getReceivedText(ssh,channelNum,"utf-8");
    if (CkSsh_getLastMethodSuccess(ssh) == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    printf("%s\n",received);

    //  Run a command whose output is delivered a page at a time.
    success = CkSsh_ChannelSendString(ssh,channelNum,"show running-config\r","utf-8");
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkSsh_Dispose(ssh);
        return;
    }

    //  Each read ends either at the device prompt (output complete) or at "--More--" (another page
    //  is waiting).  Match the full prompt rather than a bare "#", because "#" also appears inside
    //  configuration text and would match too early.
    saMatch = CkStringArray_Create();
    CkStringArray_Append(saMatch,"MySwitchName#");
    CkStringArray_Append(saMatch,"--More--");

    sbReceived = CkStringBuilder_Create();
    moreComing = TRUE;

    while (moreComing) {
        success = CkSsh_ChannelReceiveUntilMatchN(ssh,channelNum,saMatch,"utf-8",caseSensitive);
        if (success == FALSE) {
            printf("%s\n",CkSsh_lastErrorText(ssh));
            CkSsh_Dispose(ssh);
            CkStringArray_Dispose(saMatch);
            CkStringBuilder_Dispose(sbReceived);
            return;
        }

        CkStringBuilder_Clear(sbReceived);
        pageText = CkSsh_getReceivedText(ssh,channelNum,"utf-8");
        if (CkSsh_getLastMethodSuccess(ssh) == FALSE) {
            printf("%s\n",CkSsh_lastErrorText(ssh));
            CkSsh_Dispose(ssh);
            CkStringArray_Dispose(saMatch);
            CkStringBuilder_Dispose(sbReceived);
            return;
        }

        CkStringBuilder_Append(sbReceived,pageText);
        printf("%s\n",pageText);

        //  If this page ended with "--More--", send a SPACE to request the next page.
        moreComing = CkStringBuilder_Contains(sbReceived,"--More--",caseSensitive);
        if (moreComing) {
            success = CkSsh_ChannelSendString(ssh,channelNum," ","utf-8");
            if (success == FALSE) {
                printf("%s\n",CkSsh_lastErrorText(ssh));
                CkSsh_Dispose(ssh);
                CkStringArray_Dispose(saMatch);
                CkStringBuilder_Dispose(sbReceived);
                return;
            }

        }

    }

    CkSsh_Disconnect(ssh);


    CkSsh_Dispose(ssh);
    CkStringArray_Dispose(saMatch);
    CkStringBuilder_Dispose(sbReceived);

    }