2.3.5-3
[glibc.git] / resolv / gai_suspend.c
blobbb3c9c34022c9c1b9ba78b00eb521e239201bb74
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.
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.
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.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
20 #include <errno.h>
21 #include <netdb.h>
22 #include <pthread.h>
23 #include <stdlib.h>
24 #include <sys/time.h>
26 #include "gai_misc.h"
29 int
30 gai_suspend (const struct gaicb *const list[], int ent,
31 const struct timespec *timeout)
33 struct waitlist waitlist[ent];
34 struct requestlist *requestlist[ent];
35 pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
36 int cnt;
37 int dummy;
38 int none = 1;
39 int result;
41 /* Request the mutex. */
42 pthread_mutex_lock (&__gai_requests_mutex);
44 /* There is not yet a finished request. Signal the request that
45 we are working for it. */
46 for (cnt = 0; cnt < ent; ++cnt)
47 if (list[cnt] != NULL && list[cnt]->__return == EAI_INPROGRESS)
49 requestlist[cnt] = __gai_find_request (list[cnt]);
51 if (requestlist[cnt] != NULL)
53 waitlist[cnt].cond = &cond;
54 waitlist[cnt].next = requestlist[cnt]->waiting;
55 waitlist[cnt].counterp = &dummy;
56 waitlist[cnt].sigevp = NULL;
57 waitlist[cnt].caller_pid = 0; /* Not needed. */
58 requestlist[cnt]->waiting = &waitlist[cnt];
59 none = 0;
63 if (none)
65 if (cnt < ent)
66 /* There is an entry which is finished. */
67 result = 0;
68 else
69 result = EAI_ALLDONE;
71 else
73 /* There is no request done but some are still being worked on. */
74 int oldstate;
76 /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancelation
77 points we must be careful. We added entries to the waiting lists
78 which we must remove. So defer cancelation for now. */
79 pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
81 if (timeout == NULL)
82 result = pthread_cond_wait (&cond, &__gai_requests_mutex);
83 else
85 /* We have to convert the relative timeout value into an
86 absolute time value with pthread_cond_timedwait expects. */
87 struct timeval now;
88 struct timespec abstime;
90 __gettimeofday (&now, NULL);
91 abstime.tv_nsec = timeout->tv_nsec + now.tv_usec * 1000;
92 abstime.tv_sec = timeout->tv_sec + now.tv_sec;
93 if (abstime.tv_nsec >= 1000000000)
95 abstime.tv_nsec -= 1000000000;
96 abstime.tv_sec += 1;
99 result = pthread_cond_timedwait (&cond, &__gai_requests_mutex,
100 &abstime);
103 /* Now remove the entry in the waiting list for all requests
104 which didn't terminate. */
105 for (cnt = 0; cnt < ent; ++cnt)
106 if (list[cnt] != NULL && list[cnt]->__return == EAI_INPROGRESS
107 && requestlist[cnt] != NULL)
109 struct waitlist **listp = &requestlist[cnt]->waiting;
111 /* There is the chance that we cannot find our entry anymore.
112 This could happen if the request terminated and restarted
113 again. */
114 while (*listp != NULL && *listp != &waitlist[cnt])
115 listp = &(*listp)->next;
117 if (*listp != NULL)
118 *listp = (*listp)->next;
121 /* Now it's time to restore the cancelation state. */
122 pthread_setcancelstate (oldstate, NULL);
124 /* Release the conditional variable. */
125 if (pthread_cond_destroy (&cond) != 0)
126 /* This must never happen. */
127 abort ();
129 if (result != 0)
131 /* An error occurred. Possibly it's EINTR. We have to translate
132 the timeout error report of `pthread_cond_timedwait' to the
133 form expected from `gai_suspend'. */
134 if (__builtin_expect (result, ETIMEDOUT) == ETIMEDOUT)
135 result = EAI_AGAIN;
136 else if (result == EINTR)
137 result = EAI_INTR;
138 else
139 result = EAI_SYSTEM;
143 /* Release the mutex. */
144 pthread_mutex_unlock (&__gai_requests_mutex);
146 return result;