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glibc/sysdeps/pthread/aio_suspend.c
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/* Suspend until termination of a requests. | |
Copyright (C) 1997,1998,1999,2000,2002,2003 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. | |
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, write to the Free | |
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
02111-1307 USA. */ | |
/* We use an UGLY hack to prevent gcc from finding us cheating. The | |
implementations of aio_suspend and aio_suspend64 are identical and so | |
we want to avoid code duplication by using aliases. But gcc sees | |
the different parameter lists and prints a warning. We define here | |
a function so that aio_suspend64 has no prototype. */ | |
#define aio_suspend64 XXX | |
#include <aio.h> | |
/* And undo the hack. */ | |
#undef aio_suspend64 | |
#include <assert.h> | |
#include <errno.h> | |
#include <stdbool.h> | |
#include <stdlib.h> | |
#include <sys/time.h> | |
#include <bits/libc-lock.h> | |
#include "aio_misc.h" | |
struct clparam | |
{ | |
const struct aiocb *const *list; | |
struct waitlist *waitlist; | |
struct requestlist **requestlist; | |
pthread_cond_t *cond; | |
int nent; | |
}; | |
static void | |
cleanup (void *arg) | |
{ | |
const struct clparam *param = (const struct clparam *) arg; | |
/* Now remove the entry in the waiting list for all requests | |
which didn't terminate. */ | |
int cnt = param->nent; | |
while (cnt-- > 0) | |
if (param->list[cnt] != NULL | |
&& param->list[cnt]->__error_code == EINPROGRESS) | |
{ | |
struct waitlist **listp; | |
assert (param->requestlist[cnt] != NULL); | |
/* There is the chance that we cannot find our entry anymore. This | |
could happen if the request terminated and restarted again. */ | |
listp = ¶m->requestlist[cnt]->waiting; | |
while (*listp != NULL && *listp != ¶m->waitlist[cnt]) | |
listp = &(*listp)->next; | |
if (*listp != NULL) | |
*listp = (*listp)->next; | |
} | |
/* Release the conditional variable. */ | |
(void) pthread_cond_destroy (param->cond); | |
/* Release the mutex. */ | |
pthread_mutex_unlock (&__aio_requests_mutex); | |
} | |
int | |
aio_suspend (list, nent, timeout) | |
const struct aiocb *const list[]; | |
int nent; | |
const struct timespec *timeout; | |
{ | |
struct waitlist waitlist[nent]; | |
struct requestlist *requestlist[nent]; | |
pthread_cond_t cond = PTHREAD_COND_INITIALIZER; | |
int cnt; | |
bool any = false; | |
int result = 0; | |
int dummy; | |
/* Request the mutex. */ | |
pthread_mutex_lock (&__aio_requests_mutex); | |
/* There is not yet a finished request. Signal the request that | |
we are working for it. */ | |
for (cnt = 0; cnt < nent; ++cnt) | |
if (list[cnt] != NULL) | |
{ | |
if (list[cnt]->__error_code == EINPROGRESS) | |
{ | |
requestlist[cnt] = __aio_find_req ((aiocb_union *) list[cnt]); | |
if (requestlist[cnt] != NULL) | |
{ | |
waitlist[cnt].cond = &cond; | |
waitlist[cnt].next = requestlist[cnt]->waiting; | |
waitlist[cnt].counterp = &dummy; | |
waitlist[cnt].sigevp = NULL; | |
#ifdef BROKEN_THREAD_SIGNALS | |
waitlist[cnt].caller_pid = 0; /* Not needed. */ | |
#endif | |
requestlist[cnt]->waiting = &waitlist[cnt]; | |
any = true; | |
} | |
else | |
/* We will never suspend. */ | |
break; | |
} | |
else | |
/* We will never suspend. */ | |
break; | |
} | |
/* Only if none of the entries is NULL or finished to be wait. */ | |
if (cnt == nent && any) | |
{ | |
struct clparam clparam = | |
{ | |
.list = list, | |
.waitlist = waitlist, | |
.requestlist = requestlist, | |
.cond = &cond, | |
.nent = nent | |
}; | |
pthread_cleanup_push (cleanup, &clparam); | |
if (timeout == NULL) | |
result = pthread_cond_wait (&cond, &__aio_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, &__aio_requests_mutex, | |
&abstime); | |
} | |
pthread_cleanup_pop (0); | |
} | |
/* Now remove the entry in the waiting list for all requests | |
which didn't terminate. */ | |
while (cnt-- > 0) | |
if (list[cnt] != NULL && list[cnt]->__error_code == EINPROGRESS) | |
{ | |
struct waitlist **listp; | |
assert (requestlist[cnt] != NULL); | |
/* There is the chance that we cannot find our entry anymore. This | |
could happen if the request terminated and restarted again. */ | |
listp = &requestlist[cnt]->waiting; | |
while (*listp != NULL && *listp != &waitlist[cnt]) | |
listp = &(*listp)->next; | |
if (*listp != NULL) | |
*listp = (*listp)->next; | |
} | |
/* Release the conditional variable. */ | |
if (__builtin_expect (pthread_cond_destroy (&cond) != 0, 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 `aio_suspend'. */ | |
if (result == ETIMEDOUT) | |
__set_errno (EAGAIN); | |
else | |
__set_errno (result); | |
result = -1; | |
} | |
/* Release the mutex. */ | |
pthread_mutex_unlock (&__aio_requests_mutex); | |
return result; | |
} | |
weak_alias (aio_suspend, aio_suspend64) |