rt/aio_notify.c

   1 /* Notify initiator of AIO request.
   2    Copyright (C) 1997, 1998, 1999, 2000 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
  27 static void *
  28 notify_func_wrapper (void *arg)
  29 {
  30   struct sigevent *sigev = arg;
  31   sigev->sigev_notify_function (sigev->sigev_value);
  32   return NULL;
  33 }
  34
  35
  36 int
  37 internal_function
  38 __aio_notify_only (struct sigevent *sigev, pid_t caller_pid)
  39 {
  40   int result = 0;
  41
  42   /* Send the signal to notify about finished processing of the request.  */
  43   if (sigev->sigev_notify == SIGEV_THREAD)
  44     {
  45       /* We have to start a thread.  */
  46       pthread_t tid;
  47       pthread_attr_t attr, *pattr;
  48
  49       pattr = (pthread_attr_t *) sigev->sigev_notify_attributes;
  50       if (pattr == NULL)
  51         {
  52           pthread_attr_init (&attr);
  53           pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
  54           pattr = &attr;
  55         }
  56
  57       if (pthread_create (&tid, pattr, notify_func_wrapper, sigev) < 0)
  58         result = -1;
  59     }
  60   else if (sigev->sigev_notify == SIGEV_SIGNAL)
  61     /* We have to send a signal.  */
  62     if (__aio_sigqueue (sigev->sigev_signo, sigev->sigev_value, caller_pid)
  63         < 0)
  64       result = -1;
  65
  66   return result;
  67 }
  68
  69
  70 void
  71 internal_function
  72 __aio_notify (struct requestlist *req)
  73 {
  74   struct waitlist *waitlist;
  75   struct aiocb *aiocbp = &req->aiocbp->aiocb;
  76
  77   if (__aio_notify_only (&aiocbp->aio_sigevent, req->caller_pid) != 0)
  78     {
  79       /* XXX What shall we do if already an error is set by
  80          read/write/fsync?  */
  81       aiocbp->__error_code = errno;
  82       aiocbp->__return_value = -1;
  83     }
  84
  85   /* Now also notify possibly waiting threads.  */
  86   waitlist = req->waiting;
  87   while (waitlist != NULL)
  88     {
  89       struct waitlist *next = waitlist->next;
  90
  91       /* Decrement the counter.  This is used in both cases.  */
  92       --*waitlist->counterp;
  93
  94       if (waitlist->sigevp == NULL)
  95         pthread_cond_signal (waitlist->cond);
  96       else
  97         /* This is part of a asynchronous `lio_listio' operation.  If
  98            this request is the last one, send the signal.  */
  99         if (*waitlist->counterp == 0)
 100           {
 101             __aio_notify_only (waitlist->sigevp, waitlist->caller_pid);
 102             /* This is tricky.  See lio_listio.c for the reason why
 103                this works.  */
 104             free ((void *) waitlist->counterp);
 105           }
 106
 107       waitlist = next;
 108     }
 109 }