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/* Enqueue and list of read or write requests.
Copyright (C) 1997-2021 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
<https://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);
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