rt/aio_notify.c

   1 /* Notify initiator of AIO request.
   2    Copyright (C) 1997, 1998 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include <errno.h>
  22 #include <pthread.h>
  23 #include <stdlib.h>
  24 #include "aio_misc.h"
  25
  26 int
  27 __aio_notify_only (struct sigevent *sigev)
  28 {
  29   int result = 0;
  30
  31   /* Send the signal to notify about finished processing of the request.  */
  32   if (sigev->sigev_notify == SIGEV_THREAD)
  33     {
  34       /* We have to start a thread.  */
  35       pthread_t tid;
  36       pthread_attr_t attr, *pattr;
  37
  38       pattr = (pthread_attr_t *) sigev->sigev_notify_attributes;
  39       if (pattr == NULL)
  40         {
  41           pthread_attr_init (&attr);
  42           pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
  43           pattr = &attr;
  44         }
  45
  46       if (pthread_create (&tid, pattr,
  47                           (void *(*) (void *)) sigev->sigev_notify_function,
  48                           sigev->sigev_value.sival_ptr) < 0)
  49         result = -1;
  50     }
  51   else if (sigev->sigev_notify == SIGEV_SIGNAL)
  52     /* We have to send a signal.  */
  53     if (__aio_sigqueue (sigev->sigev_signo, sigev->sigev_value) < 0)
  54       result = -1;
  55
  56   return result;
  57 }
  58
  59
  60 void
  61 __aio_notify (struct requestlist *req)
  62 {
  63   struct waitlist *waitlist;
  64   struct aiocb *aiocbp = &req->aiocbp->aiocb;
  65
  66   if (__aio_notify_only (&aiocbp->aio_sigevent) != 0)
  67     {
  68       /* XXX What shall we do if already an error is set by
  69          read/write/fsync?  */
  70       aiocbp->__error_code = errno;
  71       aiocbp->__return_value = -1;
  72     }
  73
  74   /* Now also notify possibly waiting threads.  */
  75   waitlist = req->waiting;
  76   while (waitlist != NULL)
  77     {
  78       struct waitlist *next = waitlist->next;
  79
  80       /* Decrement the counter.  This is used in both cases.  */
  81       --*waitlist->counterp;
  82
  83       if (waitlist->sigevp == NULL)
  84         pthread_cond_signal (waitlist->cond);
  85       else
  86         /* This is part of a asynchronous `lio_listio' operation.  If
  87            this request is the last one, send the signal.  */
  88         if (*waitlist->counterp == 0)
  89           {
  90             __aio_notify_only (waitlist->sigevp);
  91             /* This is tricky.  See lio_listio.c for the reason why
  92                this works.  */
  93             free ((void *) waitlist->counterp);
  94           }
  95
  96       waitlist = next;
  97     }
  98 }