kdp-transactions.c   [plain text]

/* Mac OS X support for GDB, the GNU debugger.
   Copyright 1997, 1998, 1999, 2000, 2001, 2002
   Free Software Foundation, Inc.

   Contributed by Apple Computer, Inc.

   This file is part of GDB.

   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., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include "kdp-transactions.h"
#include "kdp-protocol.h"

#include <stdlib.h>

#include "defs.h"
#define assert CHECK_FATAL

static kdp_return_t
kdp_exception_reply (kdp_connection *c, kdp_pkt_t * response)
{
  kdp_return_t kdpret;
  kdp_exception_ack_t ack;

  CHECK_FATAL (kdp_is_connected (c));
  CHECK_FATAL (kdp_is_bound (c));

  ack.hdr.request = KDP_EXCEPTION;
  ack.hdr.is_reply = 1;
  ack.hdr.seq = response->exception.hdr.seq;
  ack.hdr.key = response->exception.hdr.key;

  kdpret = kdp_transmit_exception (c, (kdp_pkt_t *) & ack);
  if (kdpret != RR_SUCCESS)
    {
      c->logger (KDP_LOG_ERROR,
                 "kdp_exception_reply: unable to acknowledge exception: %s\n",
                 kdp_return_string (kdpret));
    }

  return kdpret;
}

kdp_return_t
kdp_exception_wait (kdp_connection *c, kdp_pkt_t * response, int timeout)
{
  if (c->saved_exception_pending)
    {
      memcpy (response, c->saved_exception, KDP_MAX_PACKET_SIZE);
      c->saved_exception_pending = 0;
      c->logger (KDP_LOG_DEBUG, "kdp_exception_wait: "
                 "returning previously saved exception (sequence number is %d)",
                 response->hdr.seq);
      return RR_SUCCESS;
    }

  for (;;)
    {

      kdp_return_t kdpret;

      kdpret = kdp_receive_exception (c, response, timeout);
      if (kdpret != RR_SUCCESS)
        {
          return kdpret;
        }

      kdpret = kdp_exception_reply (c, response);
      if (kdpret != RR_SUCCESS)
        {
          return kdpret;
        }

      if (response->hdr.seq == c->exc_seqno)
        {
          c->exc_seqno = (c->exc_seqno + 1) % 256;
          c->logger (KDP_LOG_DEBUG, "kdp_exception_wait: "
                     "returning previously saved exception (sequence number is %d)",
                     response->hdr.seq);
          break;
        }
      else if (((response->hdr.seq + 1) % 256) == c->exc_seqno)
        {
          /* duplicate of previous exception */
          c->logger (KDP_LOG_DEBUG, "kdp_reply_wait: "
                     "ignoring duplicate of previous exception (sequence number was %d)\n",
                     response->hdr.seq);
          continue;
        }
      else
        {
          c->logger (KDP_LOG_ERROR, "kdp_exception_wait: "
                     "unexpected sequence number for exception (expected %d, got %d)\n",
                     c->exc_seqno, response->hdr.seq);
          continue;
        }
    }

  return RR_SUCCESS;
}

kdp_return_t
kdp_reply_wait (kdp_connection *c, kdp_pkt_t * response, int timeout)
{
  for (;;)
    {

      kdp_return_t kdpret;

      kdpret = kdp_receive (c, response, timeout);
      if (kdpret != RR_SUCCESS)
        {
          c->logger (KDP_LOG_ERROR,
                     "kdp_reply_wait: error from kdp_receive: %s\n",
                     kdp_return_string (kdpret));
          return kdpret;
        }

      if (response->hdr.request == KDP_EXCEPTION)
        {

          kdpret = kdp_exception_reply (c, response);
          if (kdpret != RR_SUCCESS)
            {
              c->logger (KDP_LOG_ERROR,
                         "kdp_reply_wait: error from kdp_exception_reply: %s\n",
                         kdp_return_string (kdpret));
              return kdpret;
            }

          if (response->hdr.seq == c->exc_seqno)
            {
              c->exc_seqno = (c->exc_seqno + 1) % 256;
              /* save for future processing */
              if (c->saved_exception_pending)
                {
                  c->logger (KDP_LOG_ERROR, "kdp_reply_wait: "
                             "unable to save exception for future processing; ignoring\n");
                  c->logger (KDP_LOG_ERROR, "kdp_reply_wait: "
                             "exception had sequence number %d\n",
                             response->hdr.seq);
                  return RR_IP_ERROR;
                }
              c->logger (KDP_LOG_DEBUG, "kdp_reply_wait: "
                         "saving exception for future processing (sequence number is %d)\n",
                         response->hdr.seq);
              memcpy (c->saved_exception, response, KDP_MAX_PACKET_SIZE);
              c->saved_exception_pending = 1;
              continue;
            }
          else if (((response->hdr.seq + 1) % 256) == c->exc_seqno)
            {
              /* duplicate of previous exception */
              c->logger (KDP_LOG_DEBUG, "kdp_reply_wait: "
                         "ignoring duplicate of previous exception (sequence number was %d)\n",
                         response->hdr.seq);
              continue;
            }
          else
            {
              c->logger (KDP_LOG_ERROR, "kdp_reply_wait: "
                         "unexpected sequence number for exception (expected %d, got %d)\n",
                         c->exc_seqno, response->hdr.seq);
              continue;
            }

        }
      else
        {

          if (response->hdr.seq == c->seqno)
            {
              c->seqno = (c->seqno + 1) % 256;
              /* return reply */
              c->logger (KDP_LOG_DEBUG, "kdp_reply_wait: "
                         "returning reply (sequence number is %d)\n",
                         response->hdr.seq);
              break;
            }
          else if (((response->hdr.seq + 1) % 256) == c->exc_seqno)
            {
              /* duplicate of previous response */
              c->logger (KDP_LOG_DEBUG, "kdp_reply_wait: "
                         "ignoring duplicate of previous reply (sequence number was %d)\n",
                         response->hdr.seq);
              continue;
            }
          else
            {
              c->logger (KDP_LOG_ERROR, "kdp_reply_wait: "
                         "unexpected sequence number for reply (expected %d, got %d)\n",
                         c->seqno, response->hdr.seq);
              continue;
            }
        }
    }

  return RR_SUCCESS;
}

kdp_return_t
kdp_transaction (kdp_connection *c,
                 kdp_pkt_t * request, kdp_pkt_t * response, char *name)
{
  kdp_return_t rtn;
  int retries = c->retries;

  CHECK_FATAL (kdp_is_bound (c));

  CHECK_FATAL (request != NULL);
  CHECK_FATAL (response != NULL);
  CHECK_FATAL (name != NULL);

  request->hdr.seq = c->seqno;
  request->hdr.key = c->session_key;
  request->hdr.is_reply = 0;

  rtn = RR_RECV_TIMEOUT;

  while (retries--)
    {

      rtn = kdp_transmit_debug (c, request);
      if (rtn != RR_SUCCESS)
        {
          break;
        }

      if (c->timed_out)
        {
          rtn = kdp_reply_wait (c, response, 1);
          if (rtn == RR_RECV_TIMEOUT)
            {
              return rtn;
            }
          c->logger (KDP_LOG_INFO, "kdp_transaction (%s): "
                     "host responding; continuing transactions\n", name);
        }
      else
        {
          rtn = kdp_reply_wait (c, response, c->receive_timeout);
        }

      if (rtn == RR_RECV_TIMEOUT)
        {
          c->logger (KDP_LOG_INFO,
                     "kdp_transaction (%s): transaction timed out\n", name);
          c->logger (KDP_LOG_INFO,
                     "kdp_transaction (%s): re-sending transaction\n", name);
          continue;
        }

      break;
    }

  if (rtn == RR_RECV_TIMEOUT)
    {
      c->logger (KDP_LOG_INFO,
                 "kdp_transaction (%s): host not responding; will retry\n",
                 name);
      c->timed_out = 1;
      return rtn;
    }

  if (rtn != RR_SUCCESS)
    {
      return rtn;
    }

  /* Check for correct session key (except for CONNECT requests). */
  if ((request->hdr.request != KDP_CONNECT)
      && (response->hdr.key != c->session_key))
    {
      c->logger (KDP_LOG_ERROR,
                 "kdp_transaction (%s): invalid session key %d (expected %d)\n",
                 name, response->hdr.key, c->session_key);
      return RR_BAD_ACK;
    }

  if (!response->hdr.is_reply)
    {
      c->logger (KDP_LOG_ERROR, "kdp_transaction (%s): "
                 "response was not tagged as a reply packet\n", name);
      return RR_BAD_ACK;
    }

  if (response->hdr.request != request->hdr.request)
    {
      c->logger (KDP_LOG_ERROR, "kdp_transaction (%s):"
                 "packet type of request (%d) does not match packet type of reply (%d)\n",
                 name, request->hdr.request, response->hdr.request);
      return RR_BAD_ACK;
    }

  return RR_SUCCESS;
}

/* Perform connect sequence. Assumes a disconnected state.

   If a connect ack is lost, the target wedges. That's because all we
   can do is retransmit the connect request, with a (most likely) wrong
   session key and a zero sequence number. The target thinks it's
   connected, so it rejects these requests. */

kdp_return_t
kdp_connect (kdp_connection *c)
{
  kdp_return_t ret;

  CHECK_FATAL (kdp_is_bound (c));
  CHECK_FATAL (!kdp_is_connected (c));

  /* Do a connect transaction. */

  c->request->connect_req.hdr.request = KDP_CONNECT;
  c->request->connect_req.req_reply_port = c->reqport;
  c->request->connect_req.exc_note_port = c->excport;
  strncpy (c->request->connect_req.greeting, "", 64);
  c->request->connect_req.greeting[63] = '\0';

  ret = kdp_transaction (c, c->request, c->response, "remote_connect");
  if (ret != RR_SUCCESS)
    {
      return ret;
    }

  if (c->response->writemem_reply.error)
    {
      c->logger (KDP_LOG_ERROR, "kdp_connect: %s\n",
                 kdp_return_string (c->response->connect_reply.error));
      return RR_CONNECT;
    }

  c->session_key = c->response->hdr.key;
  c->connected = 1;

  return RR_SUCCESS;
}

kdp_return_t
kdp_disconnect (kdp_connection *c)
{
  kdp_return_t ret;

  CHECK_FATAL (kdp_is_connected (c));

  c->request->disconnect_req.hdr.request = KDP_DISCONNECT;
  ret = kdp_transaction (c, c->request, c->response, "kdp_disconnect");

  if (ret != RR_SUCCESS)
    {
      return ret;
    }

  c->connected = 0;
  return RR_SUCCESS;
}

kdp_return_t
kdp_reattach (kdp_connection *c)
{
  kdp_return_t ret;

  CHECK_FATAL (!kdp_is_connected (c));

  c->request->reattach_req.hdr.request = KDP_REATTACH;
  c->request->reattach_req.req_reply_port = c->reqport;

  ret = kdp_transaction (c, c->request, c->response, "kdp_reattach");

  if (ret != RR_SUCCESS)
    {
      return ret;
    }

  c->connected = 1;
  return RR_SUCCESS;
}

kdp_return_t
kdp_hostreboot (kdp_connection *c)
{
  kdp_return_t ret;

  CHECK_FATAL (kdp_is_connected (c));

  c->request->hostreboot_req.hdr.request = KDP_HOSTREBOOT;

  ret = kdp_transaction (c, c->request, c->response, "kdp_hostreboot");

  if (ret != RR_SUCCESS)
    {
      return ret;
    }

  c->connected = 0;
  return RR_SUCCESS;
}