Multiple SendReqExec on Same Connection

Shows how to execute a series of commands on an SSH server and retrieve each command's output (using SendReqExec). Each call to SendReqExec requires its own logical session channel. This is not a separate TCP/IP connection -- it's simply a new session channel on the existing connection. The sequence of Chilkat SSH calls would look like this:

Connect
AuthenticatePw (or AuthenticatePk)

OpenSessionChannel
SendReqExec

SendChannelClose
ChannelReceiveToClose (to make sure all remaining output is received)

OpenSessionChannel
SendReqExec

SendChannelClose
ChannelReceiveToClose (to make sure all remaining output is received)

...

OpenSessionChannel
SendReqExec

SendChannelClose
ChannelReceiveToClose (to make sure all remaining output is received)

Disconnect

Downloads:

MS Windows Visual C/C++ Libraries

Linux/CentOS C/C++ Libraries

MAC OS X C/C++ Libraries

Solaris C/C++ Libraries

C++ Builder Libraries

#include <C_CkSsh.h>

void ChilkatSample(void)
    {
    HCkSsh ssh;
    BOOL success;
    const char * hostname;
    long port;
    long channelNum;
    long n;
    long pollTimeoutMs;
    const char * cmdOutput;

    //  Important: It is helpful to send the contents of the
    //  ssh.LastErrorText property when requesting support.

    ssh = CkSsh_Create();

    //  Any string automatically begins a fully-functional 30-day trial.

    success = CkSsh_UnlockComponent(ssh,"Anything for 30-day trial");
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        return;
    }

    //  Connect to an SSH server:

    //  Hostname may be an IP address or hostname:
    hostname = "192.168.1.117";
    port = 22;

    success = CkSsh_Connect(ssh,hostname,port);
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(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));
        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));
        return;
    }

    //  Request a directory listing on the remote server:
    //  If your server is Linux/UNIX, change the string from "dir" to "ls"
    //  Note: Some SSH servers require a CRLF instead of a bare-LF
    success = CkSsh_SendReqExec(ssh,channelNum,"ls -al\n");
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(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));
        return;
    }

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

    //  Let's pickup the accumulated output of the command:

    cmdOutput = CkSsh_getReceivedText(ssh,channelNum,"ansi");
    if (cmdOutput == 0 ) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        return;
    }

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

    //  -----------------------------------------------------------------
    //  Now for the 2nd SendReqExe (on the same connection,
    //  but on a separate logical channel).
    //  -----------------------------------------------------------------

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

    success = CkSsh_SendReqExec(ssh,channelNum,"nslookup chilkatsoft.com\n");
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        return;
    }

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

    success = CkSsh_ChannelSendClose(ssh,channelNum);
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        return;
    }

    success = CkSsh_ChannelReceiveToClose(ssh,channelNum);
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        return;
    }

    cmdOutput = CkSsh_getReceivedText(ssh,channelNum,"ansi");
    if (cmdOutput == 0 ) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        return;
    }

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

    //  Disconnect
    CkSsh_Disconnect(ssh);

    CkSsh_Dispose(ssh);

    }