diff options
Diffstat (limited to 'resolv/gai_suspend.c')
| -rw-r--r-- | resolv/gai_suspend.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/resolv/gai_suspend.c b/resolv/gai_suspend.c new file mode 100644 index 0000000000..b82acb465f --- /dev/null +++ b/resolv/gai_suspend.c @@ -0,0 +1,147 @@ +/* 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; +} |