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/* Enqueue and list of read or write requests.
Copyright (C) 1997, 1998 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <aio.h>
#include <errno.h>
#include <stdlib.h>
#include "aio_misc.h"
/* We need this special structure to handle asynchronous I/O. */
struct async_waitlist
{
int counter;
struct sigevent sigev;
struct waitlist list[0];
};
int
lio_listio (mode, list, nent, sig)
int mode;
struct aiocb *const list[];
int nent;
struct sigevent *sig;
{
struct requestlist *requests[nent];
int cnt;
volatile int total = 0;
int result = 0;
/* Check arguments. */
if (mode != LIO_WAIT && mode != LIO_NOWAIT)
{
__set_errno (EINVAL);
return -1;
}
/* 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)
{
requests[cnt] = __aio_enqueue_request ((aiocb_union *) list[cnt],
list[cnt]->aio_lio_opcode);
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;
}
if (total == 0)
{
/* We don't have anything to do except signalling if we work
asynchronously. */
if (mode == LIO_NOWAIT)
__aio_notify_only (sig);
}
else if (mode == LIO_WAIT)
{
pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
struct waitlist waitlist[nent];
int oldstate;
total = 0;
for (cnt = 0; cnt < nent; ++cnt)
if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP
&& requests[cnt] != NULL)
{
waitlist[cnt].cond = &cond;
waitlist[cnt].next = requests[cnt]->waiting;
waitlist[cnt].counterp = &total;
waitlist[cnt].sigevp = NULL;
requests[cnt]->waiting = &waitlist[cnt];
++total;
}
/* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancelation
points we must be careful. We added entries to the waiting lists
which we must remove. So defer cancelation 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 cancelation state. */
pthread_setcancelstate (oldstate, NULL);
/* Release the conditional variable. */
if (pthread_cond_destroy (&cond) != 0)
/* This must never happen. */
abort ();
}
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)
if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP
&& requests[cnt] != NULL)
{
waitlist->list[cnt].cond = 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;
}
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