/* Cancel requests associated with given file descriptor.
   Copyright (C) 1997, 1998, 2000, 2002, 2003, 2005 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

/* We use an UGLY hack to prevent gcc from finding us cheating.  The
   implementation of aio_cancel and aio_cancel64 are identical and so
   we want to avoid code duplication by using aliases.  But gcc sees
   the different parameter lists and prints a warning.  We define here
   a function so that aio_cancel64 has no prototype.  */
#ifndef aio_cancel
#define aio_cancel64 XXX
#include <aio.h>
/* And undo the hack.  */
#undef aio_cancel64
#endif

#include <kaio_misc.h>

#ifndef USE_KAIO
#include <aio_cancel.c>
#else

#include <unistd.h>
#include <fcntl.h>
#include <assert.h>
#include <errno.h>

int
aio_cancel (fildes, aiocbp)
     int fildes;
     struct aiocb *aiocbp;
{
  struct requestlist *req = NULL;
  int result = AIO_ALLDONE;

  /* If fildes is invalid, error. */
  if (fcntl (fildes, F_GETFL) < 0)
    {
      __set_errno (EBADF);
      return -1;
    }

  /* Request the mutex.  */
  pthread_mutex_lock (&__aio_requests_mutex);

  /* We are asked to cancel a specific AIO request.  */
  if (aiocbp != NULL)
    {
      /* If the AIO request is not for this descriptor it has no value
	 to look for the request block.  */
      if (aiocbp->aio_fildes != fildes)
	{
	  pthread_mutex_unlock (&__aio_requests_mutex);
	  __set_errno (EINVAL);
	  return -1;
	}
      else if (aiocbp->__error_code == EINPROGRESS)
	{
	  struct requestlist *last = NULL;

	  req = __aio_find_req_fd (fildes);

	  if (req != NULL)
	    while (req->aiocbp != (aiocb_union *) aiocbp)
	      {
		last = req;
		req = req->next_prio;
		if (req == NULL)
		  break;
	      }

	  if (req != NULL)
	    {
	      /* Don't remove the entry if a thread is already working on
		 it.  */
	      if (req->running == allocated)
		{
		  result = AIO_NOTCANCELED;
		  req = NULL;
		}
	      else
		{
		  /* We can remove the entry.  */
		  __aio_remove_request (last, req, 0);

		  result = AIO_CANCELED;

		  req->next_prio = NULL;
		}
	    }
	  else
	    {
	      /* Try kernel requests.  */
	      req = __aio_find_req ((aiocb_union *) aiocbp);

	      if (req == NULL)
		{
		  pthread_mutex_unlock (&__aio_requests_mutex);
		  __set_errno (EINVAL);
		  return -1;
		}

	      assert (req->kioctx != KCTX_NONE);

	      /* If kernel is working on it, try cancelling it.  */
	      if (req->running == allocated)
		{
		  struct kio_event ev;
		  INTERNAL_SYSCALL_DECL (err);
		  int res;

		  res = INTERNAL_SYSCALL (io_cancel, err, 3, __aio_kioctx,
					  &req->kiocb, &ev);
		  if (INTERNAL_SYSCALL_ERROR_P (res, err))
		    {
		      result = AIO_NOTCANCELED;
		      req = NULL;
		    }
		  else
		    req->running = queued;
		}
	      if (req != NULL)
		{
		  /* We can remove the entry.  */
		  __aio_remove_krequest (req);
		  result = AIO_CANCELED;
		  req->next_prio = NULL;
		}
	    }
	}
    }
  else
    {
      /* Find the beginning of the list of all requests for this
	 desriptor.  */
      req = __aio_find_req_fd (fildes);

      /* If any request is worked on by a thread it must be the first.
	 So either we can delete all requests or all but the first.  */
      if (req != NULL)
	{
	  if (req->running == allocated)
	    {
	      struct requestlist *old = req;
	      req = req->next_prio;
	      old->next_prio = NULL;

	      result = AIO_NOTCANCELED;

	      if (req != NULL)
		__aio_remove_request (old, req, 1);
	    }
	  else
	    {
	      result = AIO_CANCELED;

	      /* We can remove the entry.  */
	      __aio_remove_request (NULL, req, 1);
	    }
	}

      if (result != AIO_NOTCANCELED)
	{
	  /* Try to cancel kernel requests.  */
	  struct requestlist *kreq = __aio_find_kreq_fd (fildes);

	  while (kreq)
	    {
	      struct requestlist *next;

	      /* If kernel is working on it, try cancelling it.  */
	      if (kreq->running == allocated)
		{
		  struct kio_event ev;
		  INTERNAL_SYSCALL_DECL (err);
		  int res;

		  res = INTERNAL_SYSCALL (io_cancel, err, 3, __aio_kioctx,
					  &kreq->kiocb, &ev);
		  if (INTERNAL_SYSCALL_ERROR_P (res, err))
		    {
		      result = AIO_NOTCANCELED;
		      break;
		    }
		  else
		    kreq->running = queued;
		}
	      next = kreq->next_prio;
	      __aio_remove_krequest (kreq);
	      result = AIO_CANCELED;
	      kreq->next_prio = NULL;
	      assert (kreq->running == yes || kreq->running == queued);
	      kreq->aiocbp->aiocb.__error_code = ECANCELED;
	      kreq->aiocbp->aiocb.__return_value = -1;
	      __aio_notify (kreq);
	      __aio_free_request (kreq);
	      kreq = next;
	    }
	}
    }

  /* Mark requests as canceled and send signal.  */
  while (req != NULL)
    {
      struct requestlist *old = req;
      assert (req->running == yes || req->running == queued);
      req->aiocbp->aiocb.__error_code = ECANCELED;
      req->aiocbp->aiocb.__return_value = -1;
      __aio_notify (req);
      req = req->next_prio;
      __aio_free_request (old);
    }

  /* Release the mutex.  */
  pthread_mutex_unlock (&__aio_requests_mutex);

  return result;
}

#ifndef aio_cancel
weak_alias (aio_cancel, aio_cancel64)
#endif

#endif
