sysdeps/pthread/lio_listio.c

   1 /* Enqueue and list of read or write requests.
   2    Copyright (C) 1997,1998,1999,2000,2001,2003,2005,2006
   3         Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 #ifndef lio_listio
  23 #include <aio.h>
  24 #include <assert.h>
  25 #include <errno.h>
  26 #include <stdlib.h>
  27 #include <unistd.h>
  28
  29 #include <aio_misc.h>
  30
  31 #define LIO_OPCODE_BASE 0
  32 #endif
  33
  34 #include <shlib-compat.h>
  35
  36
  37 /* We need this special structure to handle asynchronous I/O.  */
  38 struct async_waitlist
  39   {
  40     int counter;
  41     struct sigevent sigev;
  42     struct waitlist list[0];
  43   };
  44
  45
  46 /* The code in glibc 2.1 to glibc 2.4 issued only one event when all
  47    requests submitted with lio_listio finished.  The existing practice
  48    is to issue events for the individual requests as well.  This is
  49    what the new code does.  */
  50 #if SHLIB_COMPAT (librt, GLIBC_2_1, GLIBC_2_4)
  51 # define LIO_MODE(mode) ((mode) & 127)
  52 # define NO_INDIVIDUAL_EVENT_P(mode) ((mode) & 128)
  53 #else
  54 # define LIO_MODE(mode) mode
  55 # define NO_INDIVIDUAL_EVENT_P(mode) 0
  56 #endif
  57
  58
  59 static int
  60 lio_listio_internal (int mode, struct aiocb *const list[], int nent,
  61                      struct sigevent *sig)
  62 {
  63   struct sigevent defsigev;
  64   struct requestlist *requests[nent];
  65   int cnt;
  66   volatile int total = 0;
  67   int result = 0;
  68
  69   if (sig == NULL)
  70     {
  71       defsigev.sigev_notify = SIGEV_NONE;
  72       sig = &defsigev;
  73     }
  74
  75   /* Request the mutex.  */
  76   pthread_mutex_lock (&__aio_requests_mutex);
  77
  78   /* Now we can enqueue all requests.  Since we already acquired the
  79      mutex the enqueue function need not do this.  */
  80   for (cnt = 0; cnt < nent; ++cnt)
  81     if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)
  82       {
  83         if (NO_INDIVIDUAL_EVENT_P (mode))
  84           list[cnt]->aio_sigevent.sigev_notify = SIGEV_NONE;
  85
  86         requests[cnt] = __aio_enqueue_request ((aiocb_union *) list[cnt],
  87                                                (list[cnt]->aio_lio_opcode
  88                                                 | LIO_OPCODE_BASE));
  89
  90         if (requests[cnt] != NULL)
  91           /* Successfully enqueued.  */
  92           ++total;
  93         else
  94           /* Signal that we've seen an error.  `errno' and the error code
  95              of the aiocb will tell more.  */
  96           result = -1;
  97       }
  98     else
  99       requests[cnt] = NULL;
 100
 101   if (total == 0)
 102     {
 103       /* We don't have anything to do except signalling if we work
 104          asynchronously.  */
 105
 106       /* Release the mutex.  We do this before raising a signal since the
 107          signal handler might do a `siglongjmp' and then the mutex is
 108          locked forever.  */
 109       pthread_mutex_unlock (&__aio_requests_mutex);
 110
 111       if (LIO_MODE (mode) == LIO_NOWAIT)
 112         {
 113 #ifdef BROKEN_THREAD_SIGNALS
 114         __aio_notify_only (sig,
 115                            sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0);
 116 #else
 117         __aio_notify_only (sig);
 118 #endif
 119         }
 120
 121       return result;
 122     }
 123   else if (LIO_MODE (mode) == LIO_WAIT)
 124     {
 125 #ifndef DONT_NEED_AIO_MISC_COND
 126       pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
 127       int oldstate;
 128 #endif
 129       struct waitlist waitlist[nent];
 130
 131       total = 0;
 132       for (cnt = 0; cnt < nent; ++cnt)
 133         {
 134           assert (requests[cnt] == NULL || list[cnt] != NULL);
 135
 136           if (requests[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)
 137             {
 138 #ifndef DONT_NEED_AIO_MISC_COND
 139               waitlist[cnt].cond = &cond;
 140 #endif
 141               waitlist[cnt].result = &result;
 142               waitlist[cnt].next = requests[cnt]->waiting;
 143               waitlist[cnt].counterp = &total;
 144               waitlist[cnt].sigevp = NULL;
 145 #ifdef BROKEN_THREAD_SIGNALS
 146               waitlist[cnt].caller_pid = 0;     /* Not needed.  */
 147 #endif
 148               requests[cnt]->waiting = &waitlist[cnt];
 149               ++total;
 150             }
 151         }
 152
 153 #ifdef DONT_NEED_AIO_MISC_COND
 154       AIO_MISC_WAIT (result, total, NULL, 0);
 155 #else
 156       /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancellation
 157          points we must be careful.  We added entries to the waiting lists
 158          which we must remove.  So defer cancellation for now.  */
 159       pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
 160
 161       while (total > 0)
 162         pthread_cond_wait (&cond, &__aio_requests_mutex);
 163
 164       /* Now it's time to restore the cancellation state.  */
 165       pthread_setcancelstate (oldstate, NULL);
 166
 167       /* Release the conditional variable.  */
 168       if (pthread_cond_destroy (&cond) != 0)
 169         /* This must never happen.  */
 170         abort ();
 171 #endif
 172
 173       /* If any of the I/O requests failed, return -1 and set errno.  */
 174       if (result != 0)
 175         {
 176           __set_errno (result == EINTR ? EINTR : EIO);
 177           result = -1;
 178         }
 179     }
 180   else
 181     {
 182       struct async_waitlist *waitlist;
 183
 184       waitlist = (struct async_waitlist *)
 185         malloc (sizeof (struct async_waitlist)
 186                 + (nent * sizeof (struct waitlist)));
 187
 188       if (waitlist == NULL)
 189         {
 190           __set_errno (EAGAIN);
 191           result = -1;
 192         }
 193       else
 194         {
 195 #ifdef BROKEN_THREAD_SIGNALS
 196           pid_t caller_pid = sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0;
 197 #endif
 198           total = 0;
 199
 200           for (cnt = 0; cnt < nent; ++cnt)
 201             {
 202               assert (requests[cnt] == NULL || list[cnt] != NULL);
 203
 204               if (requests[cnt] != NULL
 205                   && list[cnt]->aio_lio_opcode != LIO_NOP)
 206                 {
 207 #ifndef DONT_NEED_AIO_MISC_COND
 208                   waitlist->list[cnt].cond = NULL;
 209 #endif
 210                   waitlist->list[cnt].result = NULL;
 211                   waitlist->list[cnt].next = requests[cnt]->waiting;
 212                   waitlist->list[cnt].counterp = &waitlist->counter;
 213                   waitlist->list[cnt].sigevp = &waitlist->sigev;
 214 #ifdef BROKEN_THREAD_SIGNALS
 215                   waitlist->list[cnt].caller_pid = caller_pid;
 216 #endif
 217                   requests[cnt]->waiting = &waitlist->list[cnt];
 218                   ++total;
 219                 }
 220             }
 221
 222           waitlist->counter = total;
 223           waitlist->sigev = *sig;
 224         }
 225     }
 226
 227   /* Release the mutex.  */
 228   pthread_mutex_unlock (&__aio_requests_mutex);
 229
 230   return result;
 231 }
 232
 233
 234 #if SHLIB_COMPAT (librt, GLIBC_2_1, GLIBC_2_4)
 235 int
 236 attribute_compat_text_section
 237 __lio_listio_21 (int mode, struct aiocb *const list[], int nent,
 238                  struct sigevent *sig)
 239 {
 240   /* Check arguments.  */
 241   if (mode != LIO_WAIT && mode != LIO_NOWAIT)
 242     {
 243       __set_errno (EINVAL);
 244       return -1;
 245     }
 246
 247   return lio_listio_internal (mode | LIO_NO_INDIVIDUAL_EVENT, list, nent, sig);
 248 }
 249 compat_symbol (librt, __lio_listio_21, lio_listio, GLIBC_2_1);
 250 #endif
 251
 252
 253 int
 254 __lio_listio_item_notify (int mode, struct aiocb *const list[], int nent,
 255                           struct sigevent *sig)
 256 {
 257     /* Check arguments.  */
 258   if (mode != LIO_WAIT && mode != LIO_NOWAIT)
 259     {
 260       __set_errno (EINVAL);
 261       return -1;
 262     }
 263
 264   return lio_listio_internal (mode, list, nent, sig);
 265 }
 266 versioned_symbol (librt, __lio_listio_item_notify, lio_listio, GLIBC_2_4);