resolv/gai_notify.c

   1 /* Copyright (C) 2001 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2001.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <netdb.h>
  21 #include <pthread.h>
  22 #include <stdlib.h>
  23
  24 #include "gai_misc.h"
  25
  26
  27 static void *
  28 notify_func_wrapper (void *arg)
  29 {
  30   struct sigevent *sigev = arg;
  31   sigev->sigev_notify_function (sigev->sigev_value);
  32   return NULL;
  33 }
  34
  35
  36 int
  37 internal_function
  38 __gai_notify_only (struct sigevent *sigev, pid_t caller_pid)
  39 {
  40   int result = 0;
  41
  42   /* Send the signal to notify about finished processing of the request.  */
  43   if (sigev->sigev_notify == SIGEV_THREAD)
  44     {
  45       /* We have to start a thread.  */
  46       pthread_t tid;
  47       pthread_attr_t attr, *pattr;
  48
  49       pattr = (pthread_attr_t *) sigev->sigev_notify_attributes;
  50       if (pattr == NULL)
  51         {
  52           pthread_attr_init (&attr);
  53           pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
  54           pattr = &attr;
  55         }
  56
  57       if (pthread_create (&tid, pattr, notify_func_wrapper, sigev) < 0)
  58         result = -1;
  59     }
  60   else if (sigev->sigev_notify == SIGEV_SIGNAL)
  61     /* We have to send a signal.  */
  62     if (__gai_sigqueue (sigev->sigev_signo, sigev->sigev_value, caller_pid)
  63         < 0)
  64       result = -1;
  65
  66   return result;
  67 }
  68
  69
  70 void
  71 internal_function
  72 __gai_notify (struct requestlist *req)
  73 {
  74   struct waitlist *waitlist;
  75
  76   /* Now also notify possibly waiting threads.  */
  77   waitlist = req->waiting;
  78   while (waitlist != NULL)
  79     {
  80       struct waitlist *next = waitlist->next;
  81
  82       /* Decrement the counter.  This is used in both cases.  */
  83       --*waitlist->counterp;
  84
  85       if (waitlist->sigevp == NULL)
  86         pthread_cond_signal (waitlist->cond);
  87       else
  88         /* This is part of a asynchronous `getaddrinfo_a' operation.  If
  89            this request is the last one, send the signal.  */
  90         if (*waitlist->counterp == 0)
  91           {
  92             __gai_notify_only (waitlist->sigevp, waitlist->caller_pid);
  93             /* This is tricky.  See getaddrinfo_a.c for the reason why
  94                this works.  */
  95             free ((void *) waitlist->counterp);
  96           }
  97
  98       waitlist = next;
  99     }
 100 }