1/* Copyright (C) 2001-2017 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 Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the 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 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include <netdb.h>
21#include <pthread.h>
22#include <stdlib.h>
23#include <sys/time.h>
24
25#include <gai_misc.h>
26
27
28int
29gai_suspend (const struct gaicb *const list[], int ent,
30 const struct timespec *timeout)
31{
32 struct waitlist waitlist[ent];
33 struct requestlist *requestlist[ent];
34#ifndef DONT_NEED_GAI_MISC_COND
35 pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
36#endif
37 int cnt;
38 unsigned int cntr = 1;
39 int none = 1;
40 int result;
41
42 /* Request the mutex. */
43 pthread_mutex_lock (&__gai_requests_mutex);
44
45 /* There is not yet a finished request. Signal the request that
46 we are working for it. */
47 for (cnt = 0; cnt < ent; ++cnt)
48 if (list[cnt] != NULL && list[cnt]->__return == EAI_INPROGRESS)
49 {
50 requestlist[cnt] = __gai_find_request (list[cnt]);
51
52 if (requestlist[cnt] != NULL)
53 {
54#ifndef DONT_NEED_GAI_MISC_COND
55 waitlist[cnt].cond = &cond;
56#endif
57 waitlist[cnt].next = requestlist[cnt]->waiting;
58 waitlist[cnt].counterp = &cntr;
59 waitlist[cnt].sigevp = NULL;
60 waitlist[cnt].caller_pid = 0; /* Not needed. */
61 requestlist[cnt]->waiting = &waitlist[cnt];
62 none = 0;
63 }
64 }
65
66 if (none)
67 {
68 if (cnt < ent)
69 /* There is an entry which is finished. */
70 result = 0;
71 else
72 result = EAI_ALLDONE;
73 }
74 else
75 {
76 /* There is no request done but some are still being worked on. */
77 int oldstate;
78
79 /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancelation
80 points we must be careful. We added entries to the waiting lists
81 which we must remove. So defer cancelation for now. */
82 pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
83
84#ifdef DONT_NEED_GAI_MISC_COND
85 result = 0;
86 GAI_MISC_WAIT (result, cntr, timeout, 1);
87#else
88 if (timeout == NULL)
89 result = pthread_cond_wait (&cond, &__gai_requests_mutex);
90 else
91 {
92 /* We have to convert the relative timeout value into an
93 absolute time value with pthread_cond_timedwait expects. */
94 struct timeval now;
95 struct timespec abstime;
96
97 __gettimeofday (&now, NULL);
98 abstime.tv_nsec = timeout->tv_nsec + now.tv_usec * 1000;
99 abstime.tv_sec = timeout->tv_sec + now.tv_sec;
100 if (abstime.tv_nsec >= 1000000000)
101 {
102 abstime.tv_nsec -= 1000000000;
103 abstime.tv_sec += 1;
104 }
105
106 result = pthread_cond_timedwait (&cond, &__gai_requests_mutex,
107 &abstime);
108 }
109#endif
110
111 /* Now remove the entry in the waiting list for all requests
112 which didn't terminate. */
113 for (cnt = 0; cnt < ent; ++cnt)
114 if (list[cnt] != NULL && list[cnt]->__return == EAI_INPROGRESS
115 && requestlist[cnt] != NULL)
116 {
117 struct waitlist **listp = &requestlist[cnt]->waiting;
118
119 /* There is the chance that we cannot find our entry anymore.
120 This could happen if the request terminated and restarted
121 again. */
122 while (*listp != NULL && *listp != &waitlist[cnt])
123 listp = &(*listp)->next;
124
125 if (*listp != NULL)
126 *listp = (*listp)->next;
127 }
128
129 /* Now it's time to restore the cancelation state. */
130 pthread_setcancelstate (oldstate, NULL);
131
132#ifndef DONT_NEED_GAI_MISC_COND
133 /* Release the conditional variable. */
134 if (pthread_cond_destroy (&cond) != 0)
135 /* This must never happen. */
136 abort ();
137#endif
138
139 if (result != 0)
140 {
141 /* An error occurred. Possibly it's EINTR. We have to translate
142 the timeout error report of `pthread_cond_timedwait' to the
143 form expected from `gai_suspend'. */
144 if (__builtin_expect (result, ETIMEDOUT) == ETIMEDOUT)
145 result = EAI_AGAIN;
146 else if (result == EINTR)
147 result = EAI_INTR;
148 else
149 result = EAI_SYSTEM;
150 }
151 }
152
153 /* Release the mutex. */
154 pthread_mutex_unlock (&__gai_requests_mutex);
155
156 return result;
157}
158