rt/lio_listio64.c

   1 /* Enqueue and list of read or write requests, 64bit offset version.
   2    Copyright (C) 1997, 1998, 1999 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 <aio.h>
  22 #include <errno.h>
  23 #include <stdlib.h>
  24 #include <unistd.h>
  25
  26 #include "aio_misc.h"
  27
  28
  29 /* We need this special structure to handle asynchronous I/O.  */
  30 struct async_waitlist
  31   {
  32     int counter;
  33     struct sigevent sigev;
  34     struct waitlist list[0];
  35   };
  36
  37
  38 int
  39 lio_listio64 (mode, list, nent, sig)
  40      int mode;
  41      struct aiocb64 *const list[];
  42      int nent;
  43      struct sigevent *sig;
  44 {
  45   struct requestlist *requests[nent];
  46   int cnt;
  47   volatile int total = 0;
  48   int result = 0;
  49
  50   /* Check arguments.  */
  51   if (mode != LIO_WAIT && mode != LIO_NOWAIT)
  52     {
  53       __set_errno (EINVAL);
  54       return -1;
  55     }
  56
  57   /* Request the mutex.  */
  58   pthread_mutex_lock (&__aio_requests_mutex);
  59
  60   /* Now we can enqueue all requests.  Since we already acquired the
  61      mutex the enqueue function need not do this.  */
  62   for (cnt = 0; cnt < nent; ++cnt)
  63     if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)
  64       {
  65         requests[cnt] = __aio_enqueue_request ((aiocb_union *) list[cnt],
  66                                                (list[cnt]->aio_lio_opcode
  67                                                 | 128));
  68         if (requests[cnt] != NULL)
  69           /* Successfully enqueued.  */
  70           ++total;
  71         else
  72           /* Signal that we've seen an error.  `errno' and the error code
  73              of the aiocb will tell more.  */
  74           result = -1;
  75       }
  76
  77   if (total == 0)
  78     {
  79       /* We don't have anything to do except signalling if we work
  80          asynchronously.  */
  81
  82       /* Release the mutex.  We do this before raising a signal since the
  83          signal handler might do a `siglongjmp' and then the mutex is
  84          locked forever.  */
  85       pthread_mutex_unlock (&__aio_requests_mutex);
  86
  87       if (mode == LIO_NOWAIT)
  88         __aio_notify_only (sig,
  89                            sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0);
  90
  91       return result;
  92     }
  93   else if (mode == LIO_WAIT)
  94     {
  95       pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
  96       struct waitlist waitlist[nent];
  97       int oldstate;
  98
  99       total = 0;
 100       for (cnt = 0; cnt < nent; ++cnt)
 101         if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP
 102             && requests[cnt] != NULL)
 103           {
 104             waitlist[cnt].cond = &cond;
 105             waitlist[cnt].next = requests[cnt]->waiting;
 106             waitlist[cnt].counterp = &total;
 107             waitlist[cnt].sigevp = NULL;
 108             waitlist[cnt].caller_pid = 0;       /* Not needed.  */
 109             requests[cnt]->waiting = &waitlist[cnt];
 110             ++total;
 111           }
 112
 113       /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancelation
 114          points we must be careful.  We added entries to the waiting lists
 115          which we must remove.  So defer cancelation for now.  */
 116       pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
 117
 118       while (total > 0)
 119         pthread_cond_wait (&cond, &__aio_requests_mutex);
 120
 121       /* Now it's time to restore the cancelation state.  */
 122       pthread_setcancelstate (oldstate, NULL);
 123
 124       /* Release the conditional variable.  */
 125       if (pthread_cond_destroy (&cond) != 0)
 126         /* This must never happen.  */
 127         abort ();
 128     }
 129   else
 130     {
 131       struct async_waitlist *waitlist;
 132
 133       waitlist = (struct async_waitlist *)
 134         malloc (sizeof (struct async_waitlist)
 135                 + (nent * sizeof (struct waitlist)));
 136
 137       if (waitlist == NULL)
 138         {
 139           __set_errno (EAGAIN);
 140           result = -1;
 141         }
 142       else
 143         {
 144           pid_t caller_pid = sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0;
 145           total = 0;
 146
 147           for (cnt = 0; cnt < nent; ++cnt)
 148             if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP
 149                 && requests[cnt] != NULL)
 150               {
 151                 waitlist->list[cnt].cond = NULL;
 152                 waitlist->list[cnt].next = requests[cnt]->waiting;
 153                 waitlist->list[cnt].counterp = &waitlist->counter;
 154                 waitlist->list[cnt].sigevp = &waitlist->sigev;
 155                 waitlist->list[cnt].caller_pid = caller_pid;
 156                 requests[cnt]->waiting = &waitlist->list[cnt];
 157                 ++total;
 158               }
 159
 160           waitlist->counter = total;
 161           waitlist->sigev = *sig;
 162         }
 163     }
 164
 165   /* Release the mutex.  */
 166   pthread_mutex_unlock (&__aio_requests_mutex);
 167
 168   return result;
 169 }