Question

我遇到了一个问题，我试图从伪终端调用ssh - 主人到奴隶。 / dev / ptm - 大师。我面临的问题是当我调用另一个ssh时来自子节点的会话，在调用SSH程序之前需要双重输入。

所以，这是程序 -

当我这样做时 -

./sampleProgram.out ssh -x root@13.0.0.1

然后再从那个shell调用 -

ssh -x root@13.0.0.2

- ＆GT;我需要在调用ssh之前按两次Enter键。

我在fdm和fds上尝试了fsync。但是，它没有任何区别。我错过了什么概念吗？这里或是一些程序错误。

#define _XOPEN_SOURCE 600
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#define __USE_BSD
#include <termios.h>
#include <sys/select.h>
#include <sys/ioctl.h>
#include <string.h>


int main(int ac, char *av[])
{
int fdm, fds;
int rc;
char input[150];

// Check arguments
if (ac <= 1)
{
fprintf(stderr, "Usage: %s program_name [parameters]\n", av[0]);
exit(1);
}

fdm = posix_openpt(O_RDWR);
if (fdm < 0)
{
fprintf(stderr, "Error %d on posix_openpt()\n", errno);
return 1;
}

rc = grantpt(fdm);
if (rc != 0)
{
fprintf(stderr, "Error %d on grantpt()\n", errno);
return 1;
}

rc = unlockpt(fdm);
if (rc != 0)
{
fprintf(stderr, "Error %d on unlockpt()\n", errno);
return 1;
}

// Open the slave side ot the PTY
fds = open(ptsname(fdm), O_RDWR);

// Create the child process
if (fork())
{
fd_set fd_in;

  // FATHER

  // Close the slave side of the PTY
  close(fds);

  while (1)
  {
    // Wait for data from standard input and master side of PTY
    FD_ZERO(&fd_in);
    FD_SET(0, &fd_in);
    FD_SET(fdm, &fd_in);

    rc = select(fdm + 1, &fd_in, NULL, NULL, NULL);
    switch(rc)
    {
      case -1 : fprintf(stderr, "Error %d on select()\n", errno);
                exit(1);

      default :
      {
        // If data on standard input
        if (FD_ISSET(0, &fd_in))
        {
          rc = read(0, input, sizeof(input));
          if (rc > 0)
          {
            // Send data on the master side of PTY
            write(fdm, input, rc);
          }
          else
          {
            if (rc < 0)
            {
              fprintf(stderr, "Error %d on read standard input\n", errno);
              exit(1);
            }
          }
        }

        // If data on master side of PTY
        if (FD_ISSET(fdm, &fd_in))
        {
          rc = read(fdm, input, sizeof(input));
          if (rc > 0)
          {
            // Send data on standard output
            write(1, input, rc);
          }
          else
          {
            if (rc < 0)
            {
              fprintf(stderr, "Error %d on read master PTY\n", errno);
              exit(1);
            }
          }
        }
      }
    } // End switch
  } // End while
}
else
{
struct termios slave_orig_term_settings; // Saved terminal settings
struct termios new_term_settings; // Current terminal settings

  // CHILD

  // Close the master side of the PTY
  close(fdm);

  // Save the defaults parameters of the slave side of the PTY
  rc = tcgetattr(fds, &slave_orig_term_settings);

  // Set RAW mode on slave side of PTY
  new_term_settings = slave_orig_term_settings;
  cfmakeraw (&new_term_settings);
  tcsetattr (fds, TCSANOW, &new_term_settings);

  // The slave side of the PTY becomes the standard input and outputs of the child process
  close(0); // Close standard input (current terminal)
  close(1); // Close standard output (current terminal)
  close(2); // Close standard error (current terminal)

  dup(fds); // PTY becomes standard input (0)
  dup(fds); // PTY becomes standard output (1)
  dup(fds); // PTY becomes standard error (2)

  // Now the original file descriptor is useless
  close(fds);

  // Make the current process a new session leader
  setsid();

  // As the child is a session leader, set the controlling terminal to be the slave side of the PTY
  // (Mandatory for programs like the shell to make them manage correctly their outputs)
  ioctl(0, TIOCSCTTY, 1);

  // Execution of the program
  {
  char **child_av;
  int i;

    // Build the command line
    child_av = (char **)malloc(ac * sizeof(char *));
    for (i = 1; i < ac; i ++)
    {
      child_av[i - 1] = strdup(av[i]);
    }
    child_av[i - 1] = NULL;
    rc = execvp(child_av[0], child_av);
  }

  // if Error...
  return 1;
}

return 0;
}

PseudoTerminal - Master Slave然后从slave调用另一个pseduo终端

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