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170 lines
4.7 KiB
C
170 lines
4.7 KiB
C
/* Enqueue and list of read or write requests.
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Copyright (C) 1997, 1998, 1999 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <aio.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "aio_misc.h"
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/* We need this special structure to handle asynchronous I/O. */
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struct async_waitlist
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{
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int counter;
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struct sigevent sigev;
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struct waitlist list[0];
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};
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int
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lio_listio (mode, list, nent, sig)
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int mode;
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struct aiocb *const list[];
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int nent;
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struct sigevent *sig;
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{
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struct requestlist *requests[nent];
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int cnt;
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volatile int total = 0;
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int result = 0;
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/* Check arguments. */
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if (mode != LIO_WAIT && mode != LIO_NOWAIT)
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{
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__set_errno (EINVAL);
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return -1;
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}
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/* Request the mutex. */
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pthread_mutex_lock (&__aio_requests_mutex);
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/* Now we can enqueue all requests. Since we already acquired the
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mutex the enqueue function need not do this. */
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for (cnt = 0; cnt < nent; ++cnt)
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if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)
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{
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requests[cnt] = __aio_enqueue_request ((aiocb_union *) list[cnt],
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list[cnt]->aio_lio_opcode);
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if (requests[cnt] != NULL)
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/* Successfully enqueued. */
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++total;
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else
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/* Signal that we've seen an error. `errno' and the error code
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of the aiocb will tell more. */
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result = -1;
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}
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if (total == 0)
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{
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/* We don't have anything to do except signalling if we work
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asynchronously. */
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/* Release the mutex. We do this before raising a signal since the
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signal handler might do a `siglongjmp' and then the mutex is
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locked forever. */
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pthread_mutex_unlock (&__aio_requests_mutex);
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if (mode == LIO_NOWAIT)
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__aio_notify_only (sig,
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sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0);
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return result;
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}
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else if (mode == LIO_WAIT)
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{
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pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
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struct waitlist waitlist[nent];
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int oldstate;
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total = 0;
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for (cnt = 0; cnt < nent; ++cnt)
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if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP
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&& requests[cnt] != NULL)
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{
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waitlist[cnt].cond = &cond;
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waitlist[cnt].next = requests[cnt]->waiting;
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waitlist[cnt].counterp = &total;
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waitlist[cnt].sigevp = NULL;
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waitlist[cnt].caller_pid = 0; /* Not needed. */
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requests[cnt]->waiting = &waitlist[cnt];
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++total;
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}
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/* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancelation
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points we must be careful. We added entries to the waiting lists
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which we must remove. So defer cancelation for now. */
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pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
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while (total > 0)
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pthread_cond_wait (&cond, &__aio_requests_mutex);
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/* Now it's time to restore the cancelation state. */
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pthread_setcancelstate (oldstate, NULL);
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/* Release the conditional variable. */
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if (pthread_cond_destroy (&cond) != 0)
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/* This must never happen. */
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abort ();
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}
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else
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{
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struct async_waitlist *waitlist;
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waitlist = (struct async_waitlist *)
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malloc (sizeof (struct async_waitlist)
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+ (nent * sizeof (struct waitlist)));
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if (waitlist == NULL)
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{
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__set_errno (EAGAIN);
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result = -1;
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}
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else
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{
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pid_t caller_pid = sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0;
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total = 0;
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for (cnt = 0; cnt < nent; ++cnt)
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if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP
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&& requests[cnt] != NULL)
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{
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waitlist->list[cnt].cond = NULL;
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waitlist->list[cnt].next = requests[cnt]->waiting;
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waitlist->list[cnt].counterp = &waitlist->counter;
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waitlist->list[cnt].sigevp = &waitlist->sigev;
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waitlist->list[cnt].caller_pid = caller_pid;
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requests[cnt]->waiting = &waitlist->list[cnt];
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++total;
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}
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waitlist->counter = total;
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waitlist->sigev = *sig;
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}
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}
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/* Release the mutex. */
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pthread_mutex_unlock (&__aio_requests_mutex);
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return result;
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}
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