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glibc/sysdeps/pthread/aio_notify.c
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/* Notify initiator of AIO request. | |
Copyright (C) 1997,98,99,2000,2001,2003 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. */ | |
#include <errno.h> | |
#include <pthread.h> | |
#include <stdlib.h> | |
#include <unistd.h> | |
#include "aio_misc.h" | |
struct notify_func | |
{ | |
void (*func) (sigval_t); | |
sigval_t value; | |
}; | |
static void * | |
notify_func_wrapper (void *arg) | |
{ | |
struct notify_func *const n = arg; | |
void (*func) (sigval_t) = n->func; | |
sigval_t value = n->value; | |
free (n); | |
(*func) (value); | |
return NULL; | |
} | |
int | |
internal_function | |
#ifdef BROKEN_THREAD_SIGNALS | |
__aio_notify_only (struct sigevent *sigev, pid_t caller_pid) | |
#else | |
__aio_notify_only (struct sigevent *sigev) | |
#endif | |
{ | |
int result = 0; | |
/* Send the signal to notify about finished processing of the request. */ | |
if (__builtin_expect (sigev->sigev_notify == SIGEV_THREAD, 0)) | |
{ | |
/* We have to start a thread. */ | |
pthread_t tid; | |
pthread_attr_t attr, *pattr; | |
pattr = (pthread_attr_t *) sigev->sigev_notify_attributes; | |
if (pattr == NULL) | |
{ | |
pthread_attr_init (&attr); | |
pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED); | |
pattr = &attr; | |
} | |
/* SIGEV may be freed as soon as we return, so we cannot let the | |
notification thread use that pointer. Even though a sigval_t is | |
only one word and the same size as a void *, we cannot just pass | |
the value through pthread_create as the argument and have the new | |
thread run the user's function directly, because on some machines | |
the calling convention for a union like sigval_t is different from | |
that for a pointer type like void *. */ | |
struct notify_func *nf = malloc (sizeof *nf); | |
if (nf == NULL) | |
result = -1; | |
else | |
{ | |
nf->func = sigev->sigev_notify_function; | |
nf->value = sigev->sigev_value; | |
if (pthread_create (&tid, pattr, notify_func_wrapper, nf) < 0) | |
{ | |
free (nf); | |
result = -1; | |
} | |
} | |
} | |
else if (sigev->sigev_notify == SIGEV_SIGNAL) | |
{ | |
/* We have to send a signal. */ | |
#if _POSIX_REALTIME_SIGNALS | |
/* Note that the standard gives us the option of using a plain | |
non-queuing signal here when SA_SIGINFO is not set for the signal. */ | |
# ifdef BROKEN_THREAD_SIGNALS | |
if (__aio_sigqueue (sigev->sigev_signo, sigev->sigev_value, caller_pid) | |
< 0) | |
result = -1; | |
# else | |
if (__aio_sigqueue (sigev->sigev_signo, sigev->sigev_value, getpid ()) | |
< 0) | |
result = -1; | |
# endif | |
#else | |
/* There are no queued signals on this system at all. */ | |
result = raise (sigev->sigev_signo); | |
#endif | |
} | |
return result; | |
} | |
void | |
internal_function | |
__aio_notify (struct requestlist *req) | |
{ | |
struct waitlist *waitlist; | |
struct aiocb *aiocbp = &req->aiocbp->aiocb; | |
#ifdef BROKEN_THREAD_SIGNALS | |
if (__aio_notify_only (&aiocbp->aio_sigevent, req->caller_pid) != 0) | |
#else | |
if (__aio_notify_only (&aiocbp->aio_sigevent) != 0) | |
#endif | |
{ | |
/* XXX What shall we do if already an error is set by | |
read/write/fsync? */ | |
aiocbp->__error_code = errno; | |
aiocbp->__return_value = -1; | |
} | |
/* Now also notify possibly waiting threads. */ | |
waitlist = req->waiting; | |
while (waitlist != NULL) | |
{ | |
struct waitlist *next = waitlist->next; | |
/* Decrement the counter. This is used in both cases. */ | |
--*waitlist->counterp; | |
if (waitlist->sigevp == NULL) | |
pthread_cond_signal (waitlist->cond); | |
else | |
/* This is part of a asynchronous `lio_listio' operation. If | |
this request is the last one, send the signal. */ | |
if (*waitlist->counterp == 0) | |
{ | |
#ifdef BROKEN_THREAD_SIGNALS | |
__aio_notify_only (waitlist->sigevp, waitlist->caller_pid); | |
#else | |
__aio_notify_only (waitlist->sigevp); | |
#endif | |
/* This is tricky. See lio_listio.c for the reason why | |
this works. */ | |
free ((void *) waitlist->counterp); | |
} | |
waitlist = next; | |
} | |
} |