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glibc/resolv/gai_notify.c
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/* Copyright (C) 2001-2016 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 | |
<http://www.gnu.org/licenses/>. */ | |
#include <netdb.h> | |
#include <pthread.h> | |
#include <stdlib.h> | |
#include <gai_misc.h> | |
struct notify_func | |
{ | |
void (*func) (sigval_t); | |
sigval_t value; | |
}; | |
static void * | |
notify_func_wrapper (void *arg) | |
{ | |
gai_start_notify_thread (); | |
struct notify_func *const n = arg; | |
void (*func) (sigval_t) = n->func; | |
sigval_t value = n->value; | |
free (n); | |
(*func) (value); | |
return NULL; | |
} | |
int | |
internal_function | |
__gai_notify_only (struct sigevent *sigev, pid_t caller_pid) | |
{ | |
int result = 0; | |
/* Send the signal to notify about finished processing of the request. */ | |
if (sigev->sigev_notify == SIGEV_THREAD) | |
{ | |
/* We have to start a thread. */ | |
pthread_t tid; | |
pthread_attr_t attr, *pattr; | |
pattr = (pthread_attr_t *) sigev->sigev_notify_attributes; | |
if (pattr == NULL) | |
{ | |
pthread_attr_init (&attr); | |
pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED); | |
pattr = &attr; | |
} | |
/* SIGEV may be freed as soon as we return, so we cannot let the | |
notification thread use that pointer. Even though a sigval_t is | |
only one word and the same size as a void *, we cannot just pass | |
the value through pthread_create as the argument and have the new | |
thread run the user's function directly, because on some machines | |
the calling convention for a union like sigval_t is different from | |
that for a pointer type like void *. */ | |
struct notify_func *nf = malloc (sizeof *nf); | |
if (nf == NULL) | |
result = -1; | |
else | |
{ | |
nf->func = sigev->sigev_notify_function; | |
nf->value = sigev->sigev_value; | |
if (pthread_create (&tid, pattr, notify_func_wrapper, nf) < 0) | |
{ | |
free (nf); | |
result = -1; | |
} | |
} | |
} | |
else if (sigev->sigev_notify == SIGEV_SIGNAL) | |
/* We have to send a signal. */ | |
if (__gai_sigqueue (sigev->sigev_signo, sigev->sigev_value, caller_pid) | |
< 0) | |
result = -1; | |
return result; | |
} | |
void | |
internal_function | |
__gai_notify (struct requestlist *req) | |
{ | |
struct waitlist *waitlist; | |
/* Now also notify possibly waiting threads. */ | |
waitlist = req->waiting; | |
while (waitlist != NULL) | |
{ | |
struct waitlist *next = waitlist->next; | |
if (waitlist->sigevp == NULL) | |
{ | |
#ifdef DONT_NEED_GAI_MISC_COND | |
GAI_MISC_NOTIFY (waitlist); | |
#else | |
/* Decrement the counter. */ | |
--*waitlist->counterp; | |
pthread_cond_signal (waitlist->cond); | |
#endif | |
} | |
else | |
/* This is part of an asynchronous `getaddrinfo_a' operation. If | |
this request is the last one, send the signal. */ | |
if (--*waitlist->counterp == 0) | |
{ | |
__gai_notify_only (waitlist->sigevp, waitlist->caller_pid); | |
/* This is tricky. See getaddrinfo_a.c for the reason why | |
this works. */ | |
free ((void *) waitlist->counterp); | |
} | |
waitlist = next; | |
} | |
} |