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/* Copyright (C) 2001-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2001.
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/>. */
#include <errno.h>
#include <netdb.h>
#include <pthread.h>
#include <stdlib.h>
#include <unistd.h>
#include <gai_misc.h>
/* We need this special structure to handle asynchronous I/O. */
struct async_waitlist
{
unsigned int counter;
struct sigevent sigev;
struct waitlist list[0];
};
int
getaddrinfo_a (int mode, struct gaicb *list[], int ent, struct sigevent *sig)
{
struct sigevent defsigev;
struct requestlist *requests[ent];
int cnt;
volatile unsigned int total = 0;
int result = 0;
/* Check arguments. */
if (mode != GAI_WAIT && mode != GAI_NOWAIT)
{
__set_errno (EINVAL);
return EAI_SYSTEM;
}
if (sig == NULL)
{
defsigev.sigev_notify = SIGEV_NONE;
sig = &defsigev;
}
/* Request the mutex. */
pthread_mutex_lock (&__gai_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 < ent; ++cnt)
if (list[cnt] != NULL)
{
requests[cnt] = __gai_enqueue_request (list[cnt]);
if (requests[cnt] != NULL)
/* Successfully enqueued. */
++total;
else
/* Signal that we've seen an error. `errno' and the error code
of the gaicb will tell more. */
result = EAI_SYSTEM;
}
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 (&__gai_requests_mutex);
if (mode == GAI_NOWAIT)
__gai_notify_only (sig,
sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0);
return result;
}
else if (mode == GAI_WAIT)
{
#ifndef DONT_NEED_GAI_MISC_COND
pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
#endif
struct waitlist waitlist[ent];
int oldstate;
total = 0;
for (cnt = 0; cnt < ent; ++cnt)
if (requests[cnt] != NULL)
{
#ifndef DONT_NEED_GAI_MISC_COND
waitlist[cnt].cond = &cond;
#endif
waitlist[cnt].next = requests[cnt]->waiting;
waitlist[cnt].counterp = &total;
waitlist[cnt].sigevp = NULL;
waitlist[cnt].caller_pid = 0; /* Not needed. */
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)
{
#ifdef DONT_NEED_GAI_MISC_COND
int not_used __attribute__ ((unused));
GAI_MISC_WAIT (not_used, total, NULL, 1);
#else
pthread_cond_wait (&cond, &__gai_requests_mutex);
#endif
}
/* Now it's time to restore the cancelation state. */
pthread_setcancelstate (oldstate, NULL);
#ifndef DONT_NEED_GAI_MISC_COND
/* Release the conditional variable. */
if (pthread_cond_destroy (&cond) != 0)
/* This must never happen. */
abort ();
#endif
}
else
{
struct async_waitlist *waitlist;
waitlist = (struct async_waitlist *)
malloc (sizeof (struct async_waitlist)
+ (ent * sizeof (struct waitlist)));
if (waitlist == NULL)
result = EAI_AGAIN;
else
{
pid_t caller_pid = sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0;
total = 0;
for (cnt = 0; cnt < ent; ++cnt)
if (requests[cnt] != NULL)
{
#ifndef DONT_NEED_GAI_MISC_COND
waitlist->list[cnt].cond = NULL;
#endif
waitlist->list[cnt].next = requests[cnt]->waiting;
waitlist->list[cnt].counterp = &waitlist->counter;
waitlist->list[cnt].sigevp = &waitlist->sigev;
waitlist->list[cnt].caller_pid = caller_pid;
requests[cnt]->waiting = &waitlist->list[cnt];
++total;
}
waitlist->counter = total;
waitlist->sigev = *sig;
}
}
/* Release the mutex. */
pthread_mutex_unlock (&__gai_requests_mutex);
return result;
}
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