summary refs log tree commit diff
path: root/resolv/gai_suspend.c
blob: b795cdecb83fb710788e07c14ad5a7d2fc6f0e38 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
/* Copyright (C) 2001-2014 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 <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];
#ifndef DONT_NEED_GAI_MISC_COND
  pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
#endif
  int cnt;
  int cntr = 1;
  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)
	  {
#ifndef DONT_NEED_GAI_MISC_COND
	    waitlist[cnt].cond = &cond;
#endif
	    waitlist[cnt].next = requestlist[cnt]->waiting;
	    waitlist[cnt].counterp = &cntr;
	    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);

#ifdef DONT_NEED_GAI_MISC_COND
      result = 0;
      GAI_MISC_WAIT (result, cntr, timeout, 1);
#else
      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);
	}
#endif

      /* 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);

#ifndef DONT_NEED_GAI_MISC_COND
      /* Release the conditional variable.  */
      if (pthread_cond_destroy (&cond) != 0)
	/* This must never happen.  */
	abort ();
#endif

      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;
}