/* Enqueue and list of read or write requests.

   Copyright (C) 1997-2018 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, see

   <http://www.gnu.org/licenses/>.  */

#ifndef lio_listio

#include <aio.h>

#include <assert.h>

#include <errno.h>

#include <stdlib.h>

#include <unistd.h>

#include <aio_misc.h>

#define LIO_OPCODE_BASE 0

#endif

#include <shlib-compat.h>

/* We need this special structure to handle asynchronous I/O.  */

struct async_waitlist

  {

    unsigned int counter;

    struct sigevent sigev;

    struct waitlist list[0];

  };

/* The code in glibc 2.1 to glibc 2.4 issued only one event when all

   requests submitted with lio_listio finished.  The existing practice

   is to issue events for the individual requests as well.  This is

   what the new code does.  */

#if SHLIB_COMPAT (librt, GLIBC_2_1, GLIBC_2_4)

# define LIO_MODE(mode) ((mode) & 127)

# define NO_INDIVIDUAL_EVENT_P(mode) ((mode) & 128)

#else

# define LIO_MODE(mode) mode

# define NO_INDIVIDUAL_EVENT_P(mode) 0

#endif

static int

lio_listio_internal (int mode, struct aiocb *const list[], int nent,

		     struct sigevent *sig)

{

  struct sigevent defsigev;

  struct requestlist *requests[nent];

  int cnt;

  volatile unsigned int total = 0;

  int result = 0;

  if (sig == NULL)

    {

      defsigev.sigev_notify = SIGEV_NONE;

      sig = &defsigev;

    }

  /* Request the mutex.  */

  pthread_mutex_lock (&__aio_requests_mutex);

  /* Now we can enqueue all requests.  Since we already acquired the

     mutex the enqueue function need not do this.  */

  for (cnt = 0; cnt < nent; ++cnt)

    if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)

      {

	if (NO_INDIVIDUAL_EVENT_P (mode))

	  list[cnt]->aio_sigevent.sigev_notify = SIGEV_NONE;

	requests[cnt] = __aio_enqueue_request ((aiocb_union *) list[cnt],

					       (list[cnt]->aio_lio_opcode

						| LIO_OPCODE_BASE));

	if (requests[cnt] != NULL)

	  /* Successfully enqueued.  */

	  ++total;

	else

	  /* Signal that we've seen an error.  `errno' and the error code

	     of the aiocb will tell more.  */

	  result = -1;

      }

    else

      requests[cnt] = NULL;

  if (total == 0)

    {

      /* We don't have anything to do except signalling if we work

	 asynchronously.  */

      /* Release the mutex.  We do this before raising a signal since the

	 signal handler might do a `siglongjmp' and then the mutex is

	 locked forever.  */

      pthread_mutex_unlock (&__aio_requests_mutex);

      if (LIO_MODE (mode) == LIO_NOWAIT)

	__aio_notify_only (sig);

      return result;

    }

  else if (LIO_MODE (mode) == LIO_WAIT)

    {

#ifndef DONT_NEED_AIO_MISC_COND

      pthread_cond_t cond = PTHREAD_COND_INITIALIZER;

      int oldstate;

#endif

      struct waitlist waitlist[nent];

      total = 0;

      for (cnt = 0; cnt < nent; ++cnt)

	{

	  assert (requests[cnt] == NULL || list[cnt] != NULL);

	  if (requests[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)

	    {

#ifndef DONT_NEED_AIO_MISC_COND

	      waitlist[cnt].cond = &cond;

#endif

	      waitlist[cnt].result = &result;

	      waitlist[cnt].next = requests[cnt]->waiting;

	      waitlist[cnt].counterp = &total;

	      waitlist[cnt].sigevp = NULL;

	      requests[cnt]->waiting = &waitlist[cnt];

	      ++total;

	    }

	}

#ifdef DONT_NEED_AIO_MISC_COND

      AIO_MISC_WAIT (result, total, NULL, 0);

#else

      /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancellation

	 points we must be careful.  We added entries to the waiting lists

	 which we must remove.  So defer cancellation for now.  */

      pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);

      while (total > 0)

	pthread_cond_wait (&cond, &__aio_requests_mutex);

      /* Now it's time to restore the cancellation state.  */

      pthread_setcancelstate (oldstate, NULL);

      /* Release the conditional variable.  */

      if (pthread_cond_destroy (&cond) != 0)

	/* This must never happen.  */

	abort ();

#endif

      /* If any of the I/O requests failed, return -1 and set errno.  */

      if (result != 0)

	{

	  __set_errno (result == EINTR ? EINTR : EIO);

	  result = -1;

	}

    }

  else

    {

      struct async_waitlist *waitlist;

      waitlist = (struct async_waitlist *)

	malloc (sizeof (struct async_waitlist)

		+ (nent * sizeof (struct waitlist)));

      if (waitlist == NULL)

	{

	  __set_errno (EAGAIN);

	  result = -1;

	}

      else

	{

	  total = 0;

	  for (cnt = 0; cnt < nent; ++cnt)

	    {

	      assert (requests[cnt] == NULL || list[cnt] != NULL);

	      if (requests[cnt] != NULL

		  && list[cnt]->aio_lio_opcode != LIO_NOP)

		{

#ifndef DONT_NEED_AIO_MISC_COND

		  waitlist->list[cnt].cond = NULL;

#endif

		  waitlist->list[cnt].result = NULL;

		  waitlist->list[cnt].next = requests[cnt]->waiting;

		  waitlist->list[cnt].counterp = &waitlist->counter;

		  waitlist->list[cnt].sigevp = &waitlist->sigev;

		  requests[cnt]->waiting = &waitlist->list[cnt];

		  ++total;

		}

	    }

	  waitlist->counter = total;

	  waitlist->sigev = *sig;

	}

    }

  /* Release the mutex.  */

  pthread_mutex_unlock (&__aio_requests_mutex);

  return result;

}

#if SHLIB_COMPAT (librt, GLIBC_2_1, GLIBC_2_4)

int

attribute_compat_text_section

__lio_listio_21 (int mode, struct aiocb *const list[], int nent,

		 struct sigevent *sig)

{

  /* Check arguments.  */

  if (mode != LIO_WAIT && mode != LIO_NOWAIT)

    {

      __set_errno (EINVAL);

      return -1;

    }

  return lio_listio_internal (mode | LIO_NO_INDIVIDUAL_EVENT, list, nent, sig);

}

compat_symbol (librt, __lio_listio_21, lio_listio, GLIBC_2_1);

#endif

int

__lio_listio_item_notify (int mode, struct aiocb *const list[], int nent,

			  struct sigevent *sig)

{

    /* Check arguments.  */

  if (mode != LIO_WAIT && mode != LIO_NOWAIT)

    {

      __set_errno (EINVAL);

      return -1;

    }

  return lio_listio_internal (mode, list, nent, sig);

}

versioned_symbol (librt, __lio_listio_item_notify, lio_listio, GLIBC_2_4);