sysdeps/pthread/aio_notify.c

   1 /* Notify initiator of AIO request.
   2    Copyright (C) 1997,98,99,2000,01 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 Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the 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    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <errno.h>
  22 #include <pthread.h>
  23 #include <stdlib.h>
  24 #include <unistd.h>
  25 #include "aio_misc.h"
  26
  27
  28 static void *
  29 notify_func_wrapper (void *arg)
  30 {
  31   struct sigevent *sigev = arg;
  32   sigev->sigev_notify_function (sigev->sigev_value);
  33   return NULL;
  34 }
  35
  36
  37 int
  38 internal_function
  39 __aio_notify_only (struct sigevent *sigev, pid_t caller_pid)
  40 {
  41   int result = 0;
  42
  43   /* Send the signal to notify about finished processing of the request.  */
  44   if (sigev->sigev_notify == SIGEV_THREAD)
  45     {
  46       /* We have to start a thread.  */
  47       pthread_t tid;
  48       pthread_attr_t attr, *pattr;
  49
  50       pattr = (pthread_attr_t *) sigev->sigev_notify_attributes;
  51       if (pattr == NULL)
  52         {
  53           pthread_attr_init (&attr);
  54           pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
  55           pattr = &attr;
  56         }
  57
  58       if (pthread_create (&tid, pattr, notify_func_wrapper, sigev) < 0)
  59         result = -1;
  60     }
  61   else if (sigev->sigev_notify == SIGEV_SIGNAL)
  62     {
  63       /* We have to send a signal.  */
  64 #if _POSIX_REALTIME_SIGNALS
  65       /* Note that the standard gives us the option of using a plain
  66          non-queuing signal here when SA_SIGINFO is not set for the signal.  */
  67       if (__aio_sigqueue (sigev->sigev_signo, sigev->sigev_value, caller_pid)
  68           < 0)
  69         result = -1;
  70 #else
  71       /* There are no queued signals on this system at all.  */
  72       result = raise (sigev->sigev_signo);
  73 #endif
  74     }
  75
  76   return result;
  77 }
  78
  79
  80 void
  81 internal_function
  82 __aio_notify (struct requestlist *req)
  83 {
  84   struct waitlist *waitlist;
  85   struct aiocb *aiocbp = &req->aiocbp->aiocb;
  86
  87   if (__aio_notify_only (&aiocbp->aio_sigevent, req->caller_pid) != 0)
  88     {
  89       /* XXX What shall we do if already an error is set by
  90          read/write/fsync?  */
  91       aiocbp->__error_code = errno;
  92       aiocbp->__return_value = -1;
  93     }
  94
  95   /* Now also notify possibly waiting threads.  */
  96   waitlist = req->waiting;
  97   while (waitlist != NULL)
  98     {
  99       struct waitlist *next = waitlist->next;
 100
 101       /* Decrement the counter.  This is used in both cases.  */
 102       --*waitlist->counterp;
 103
 104       if (waitlist->sigevp == NULL)
 105         pthread_cond_signal (waitlist->cond);
 106       else
 107         /* This is part of a asynchronous `lio_listio' operation.  If
 108            this request is the last one, send the signal.  */
 109         if (*waitlist->counterp == 0)
 110           {
 111             __aio_notify_only (waitlist->sigevp, waitlist->caller_pid);
 112             /* This is tricky.  See lio_listio.c for the reason why
 113                this works.  */
 114             free ((void *) waitlist->counterp);
 115           }
 116
 117       waitlist = next;
 118     }
 119 }