/*
 * Copyright (c) 1995, 1996 Gunther Schadow.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "pg_config.h"
#include "ptydrv.h"
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <unistd.h>
#include <syslog.h>
#include "trap.h"

static volatile bool ch_exited;
static volatile int  ch_result;
static volatile int  ch_signal;
static pid_t ch_pid;
static jmp_buf  released_by_server;

static void
reaper(int sig)
{
  int status;

  syslog(LOG_DEBUG, "reaper called by signal %d `%s'",
	 sig, sys_siglist[sig]);

  if(waitpid(ch_pid, &status, 0) == FAIL)
    syslog(LOG_ERR, "waitpid: %m");

  if(WIFEXITED(status))
    {
      ch_exited = TRUE;
      ch_result = WEXITSTATUS(status);
      DBG(syslog(LOG_DEBUG, "process %d exited with %d", ch_pid, ch_result));
      if(ch_result == 0) longjmp(released_by_server, TRUE);
    }
  else if(WIFSIGNALED(status))
    {
      ch_exited = TRUE;
      ch_signal = WTERMSIG(status);
      syslog(LOG_DEBUG, "process %d received signal %d `%s'",
	     ch_pid, ch_signal, sys_siglist[ch_signal]);
    }
  else if(WIFSTOPPED(status))
    {
      ch_exited = FALSE;
      ch_signal = WSTOPSIG(status);
      syslog(LOG_DEBUG, "process %d stopped by signal %d `s'",
	     ch_pid, ch_signal, sys_siglist[ch_signal]);
      kill(ch_pid, SIGCONT);
    }
}

result
duplex(int mfd, int dfd)
{
  ch_exited = FALSE;
  ch_signal = 0;
  ch_result = -1;

  ssignal(SIGCHLD, reaper, 0);

  if(setjmp(released_by_server)) goto success;
  
  if((ch_pid = fork()) == FAIL)
    {
      syslog(LOG_ERR,"fork: %m");
      return FAIL;
    }

  if(ch_pid == 0) /* I am the child */
    {
      if(bwddata(dfd, mfd) == FAIL)
	exit(1);
      else
	exit(0);
    }
  else /* I am the parent */
    {
      if(fwddata(mfd, dfd) == FAIL)
	goto fail;
    }
  
  /* Fwddata returns only when there is noone refering to
   * the slave side of the pty, thus we don't need to give time
   * to the children.
   */
#ifdef LET_THE_CHILDREN_PLAY
  /*
   * Wait up to TIMEOUT seconds for child process to finish
   */
#define TIMEOUT 30
  attimeout(TIMEOUT) goto kill_children;
  while(!ch_exited);
  ctimeout();
  goto success;
#endif
  
 kill_children:
  kill(ch_pid, SIGHUP);

 success:
  return SUCCESS;
  
 fail:
  /*
   * Kill child process
   */
  kill(ch_pid, SIGHUP);
  ctimeout();
  
  return FAIL;  
}


result
bwddata(int dfd, int mfd)
{
  char buf[BUF_SIZE + 1];
  int cnt;
  size_t total = 0;
  
  atsignal(SIGHUP, 0) goto success;

  do
    {
      DBG(syslog(LOG_DEBUG, "reading from pty"));

      cnt = read(dfd, buf, BUF_SIZE);
      
      if (cnt < 0) /* error */
	{
	  syslog(LOG_ERR, "read: %m");
	  goto fail;
	}
      else if (cnt > 0) /* normal data */
	{
	  int ncnt, wcnt = cnt, start = 0;
	  
	  DBG(syslog(LOG_DEBUG, "writing %d bytes to %s", cnt, master));
	  
	  do
	    {
	      ncnt = write(mfd, &buf[start], wcnt);	      
	      TSW(&buf[start], wcnt);	      
	  
	      if (ncnt < 1)
		{
		  syslog(LOG_ERR, "write: %m");
		  goto fail;
		}
	      
	      wcnt  -= ncnt;
	      start += ncnt;
	      total += ncnt;
	    }
	  while(wcnt > 0);
	}
      else
	DBG(syslog(LOG_DEBUG, "read returned 0"));
    }
  while(cnt != 0);

 success:
  csignal(SIGHUP);
  syslog(LOG_INFO, "%lu bytes transfered", total);
  return SUCCESS;

 fail:
  csignal(SIGHUP);
  syslog(LOG_INFO, "%lu bytes transfered", total);
  return FAIL;
}