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-rw-r--r--resolv/gai_suspend.c147
1 files changed, 147 insertions, 0 deletions
diff --git a/resolv/gai_suspend.c b/resolv/gai_suspend.c
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+/* Copyright (C) 2001 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 Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <errno.h>
+#include <netdb.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <sys/time.h>
+
+#include "gai_misc.h"
+
+
+int
+gai_suspend (const struct gaicb *const list[], int ent,
+	     const struct timespec *timeout)
+{
+  struct waitlist waitlist[ent];
+  struct requestlist *requestlist[ent];
+  pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
+  int cnt;
+  int dummy;
+  int none = 1;
+  int result;
+
+  /* Request the mutex.  */
+  pthread_mutex_lock (&__gai_requests_mutex);
+
+  /* There is not yet a finished request.  Signal the request that
+     we are working for it.  */
+  for (cnt = 0; cnt < ent; ++cnt)
+    if (list[cnt] != NULL && list[cnt]->__return == EAI_INPROGRESS)
+      {
+	requestlist[cnt] = __gai_find_request (list[cnt]);
+
+	if (requestlist[cnt] != NULL)
+	  {
+	    waitlist[cnt].cond = &cond;
+	    waitlist[cnt].next = requestlist[cnt]->waiting;
+	    waitlist[cnt].counterp = &dummy;
+	    waitlist[cnt].sigevp = NULL;
+	    waitlist[cnt].caller_pid = 0;	/* Not needed.  */
+	    requestlist[cnt]->waiting = &waitlist[cnt];
+	    none = 0;
+	  }
+      }
+
+  if (none)
+    {
+      if (cnt < ent)
+	/* There is an entry which is finished.  */
+	result = 0;
+      else
+	result = EAI_ALLDONE;
+    }
+  else
+    {
+      /* There is no request done but some are still being worked on.  */
+      int oldstate;
+
+      /* 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);
+
+      if (timeout == NULL)
+	result = pthread_cond_wait (&cond, &__gai_requests_mutex);
+      else
+	{
+	  /* We have to convert the relative timeout value into an
+	     absolute time value with pthread_cond_timedwait expects.  */
+	  struct timeval now;
+	  struct timespec abstime;
+
+	  __gettimeofday (&now, NULL);
+	  abstime.tv_nsec = timeout->tv_nsec + now.tv_usec * 1000;
+	  abstime.tv_sec = timeout->tv_sec + now.tv_sec;
+	  if (abstime.tv_nsec >= 1000000000)
+	    {
+	      abstime.tv_nsec -= 1000000000;
+	      abstime.tv_sec += 1;
+	    }
+
+	  result = pthread_cond_timedwait (&cond, &__gai_requests_mutex,
+					   &abstime);
+	}
+
+      /* Now remove the entry in the waiting list for all requests
+	 which didn't terminate.  */
+      for (cnt = 0; cnt < ent; ++cnt)
+	if (list[cnt] != NULL && list[cnt]->__return == EAI_INPROGRESS
+	    && requestlist[cnt] != NULL)
+	  {
+	    struct waitlist **listp = &requestlist[cnt]->waiting;
+
+	    /* There is the chance that we cannot find our entry anymore.
+	       This could happen if the request terminated and restarted
+	       again.  */
+	    while (*listp != NULL && *listp != &waitlist[cnt])
+	      listp = &(*listp)->next;
+
+	    if (*listp != NULL)
+	      *listp = (*listp)->next;
+	  }
+
+      /* Now it's time to restore the cancelation state.  */
+      pthread_setcancelstate (oldstate, NULL);
+
+      /* Release the conditional variable.  */
+      if (pthread_cond_destroy (&cond) != 0)
+	/* This must never happen.  */
+	abort ();
+
+      if (result != 0)
+	{
+	  /* An error occurred.  Possibly it's EINTR.  We have to translate
+	     the timeout error report of `pthread_cond_timedwait' to the
+	     form expected from `gai_suspend'.  */
+	  if (__builtin_expect (result, ETIMEDOUT) == ETIMEDOUT)
+	    result = EAI_AGAIN;
+	  else if (result == EINTR)
+	    result = EAI_INTR;
+	  else
+	    result = EAI_SYSTEM;
+	}
+    }
+
+  /* Release the mutex.  */
+  pthread_mutex_unlock (&__gai_requests_mutex);
+
+  return result;
+}