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glibc/sysdeps/pthread/lio_listio.c
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/* Enqueue and list of read or write requests. | |
Copyright (C) 1997,1998,1999,2000,2001,2003 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. */ | |
#ifndef lio_listio | |
#include <aio.h> | |
#include <assert.h> | |
#include <errno.h> | |
#include <stdlib.h> | |
#include <unistd.h> | |
#include "aio_misc.h" | |
#define LIO_OPCODE_BASE 0 | |
#endif | |
/* We need this special structure to handle asynchronous I/O. */ | |
struct async_waitlist | |
{ | |
int counter; | |
struct sigevent sigev; | |
struct waitlist list[0]; | |
}; | |
int | |
lio_listio (mode, list, nent, sig) | |
int mode; | |
struct aiocb *const list[]; | |
int nent; | |
struct sigevent *sig; | |
{ | |
struct sigevent defsigev; | |
struct requestlist *requests[nent]; | |
int cnt; | |
volatile int total = 0; | |
int result = 0; | |
/* Check arguments. */ | |
if (mode != LIO_WAIT && mode != LIO_NOWAIT) | |
{ | |
__set_errno (EINVAL); | |
return -1; | |
} | |
if (sig == NULL) | |
{ | |
defsigev.sigev_notify = SIGEV_NONE; | |
sig = &defsigev; | |
} | |
/* Request the mutex. */ | |
pthread_mutex_lock (&__aio_requests_mutex); | |
/* Now we can enqueue all requests. Since we already acquired the | |
mutex the enqueue function need not do this. */ | |
for (cnt = 0; cnt < nent; ++cnt) | |
if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP) | |
{ | |
list[cnt]->aio_sigevent.sigev_notify = SIGEV_NONE; | |
requests[cnt] = __aio_enqueue_request ((aiocb_union *) list[cnt], | |
(list[cnt]->aio_lio_opcode | |
| LIO_OPCODE_BASE)); | |
if (requests[cnt] != NULL) | |
/* Successfully enqueued. */ | |
++total; | |
else | |
/* Signal that we've seen an error. `errno' and the error code | |
of the aiocb will tell more. */ | |
result = -1; | |
} | |
else | |
requests[cnt] = NULL; | |
if (total == 0) | |
{ | |
/* We don't have anything to do except signalling if we work | |
asynchronously. */ | |
/* Release the mutex. We do this before raising a signal since the | |
signal handler might do a `siglongjmp' and then the mutex is | |
locked forever. */ | |
pthread_mutex_unlock (&__aio_requests_mutex); | |
if (mode == LIO_NOWAIT) | |
__aio_notify_only (sig, | |
sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0); | |
return result; | |
} | |
else if (mode == LIO_WAIT) | |
{ | |
pthread_cond_t cond = PTHREAD_COND_INITIALIZER; | |
struct waitlist waitlist[nent]; | |
int oldstate; | |
total = 0; | |
for (cnt = 0; cnt < nent; ++cnt) | |
{ | |
assert (requests[cnt] == NULL || list[cnt] != NULL); | |
if (requests[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP) | |
{ | |
waitlist[cnt].cond = &cond; | |
waitlist[cnt].next = requests[cnt]->waiting; | |
waitlist[cnt].counterp = &total; | |
waitlist[cnt].sigevp = NULL; | |
waitlist[cnt].caller_pid = 0; /* Not needed. */ | |
requests[cnt]->waiting = &waitlist[cnt]; | |
++total; | |
} | |
} | |
/* 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); | |
while (total > 0) | |
pthread_cond_wait (&cond, &__aio_requests_mutex); | |
/* 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 (); | |
} | |
else | |
{ | |
struct async_waitlist *waitlist; | |
waitlist = (struct async_waitlist *) | |
malloc (sizeof (struct async_waitlist) | |
+ (nent * sizeof (struct waitlist))); | |
if (waitlist == NULL) | |
{ | |
__set_errno (EAGAIN); | |
result = -1; | |
} | |
else | |
{ | |
pid_t caller_pid = sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0; | |
total = 0; | |
for (cnt = 0; cnt < nent; ++cnt) | |
{ | |
assert (requests[cnt] == NULL || list[cnt] != NULL); | |
if (requests[cnt] != NULL | |
&& list[cnt]->aio_lio_opcode != LIO_NOP) | |
{ | |
waitlist->list[cnt].cond = NULL; | |
waitlist->list[cnt].next = requests[cnt]->waiting; | |
waitlist->list[cnt].counterp = &waitlist->counter; | |
waitlist->list[cnt].sigevp = &waitlist->sigev; | |
waitlist->list[cnt].caller_pid = caller_pid; | |
requests[cnt]->waiting = &waitlist->list[cnt]; | |
++total; | |
} | |
} | |
waitlist->counter = total; | |
waitlist->sigev = *sig; | |
} | |
} | |
/* Release the mutex. */ | |
pthread_mutex_unlock (&__aio_requests_mutex); | |
return result; | |
} |