rt/lio_listio-common.c

   1 /* Enqueue and list of read or write requests.  Common code template.
   2    Copyright (C) 1997-2021 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, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 /* The following macros must be defined before including this file:
  21
  22    LIO_LISTIO         The public symbol (lio_listio or lio_listio64).
  23    AIOCB              Struct tag used by LIO_LISTIO (aiocb or aiocb64).
  24    LIO_LISTIO_OLD     The internal symbol for the compat implementation.
  25    LIO_LISTIO_NEW     The internal symbol for the current implementation.
  26    LIO_OPCODE_BASE    Opcode shift for 64-bit version with 32-bit word size.
  27
  28    For __WORDSIZE == 64, LIO_LISTIO must always be lio_listio, and
  29    lio_listio64 is automatically defined as well.  */
  30
  31 #include <bits/wordsize.h>
  32 #if __WORDSIZE == 64
  33 # define lio_listio64 XXX
  34 # include <aio.h>
  35 /* And undo the hack.  */
  36 # undef lio_listio64
  37 #else
  38 # include <aio.h>
  39 #endif
  40
  41 #include <assert.h>
  42 #include <errno.h>
  43 #include <stdlib.h>
  44 #include <unistd.h>
  45 #include <pthreadP.h>
  46
  47 #include <aio_misc.h>
  48
  49 #include <shlib-compat.h>
  50
  51
  52 /* We need this special structure to handle asynchronous I/O.  */
  53 struct async_waitlist
  54   {
  55     unsigned int counter;
  56     struct sigevent sigev;
  57     struct waitlist list[0];
  58   };
  59
  60
  61 /* The code in glibc 2.1 to glibc 2.4 issued only one event when all
  62    requests submitted with lio_listio finished.  The existing practice
  63    is to issue events for the individual requests as well.  This is
  64    what the new code does.  */
  65 #if SHLIB_COMPAT (librt, GLIBC_2_1, GLIBC_2_4)
  66 # define LIO_MODE(mode) ((mode) & 127)
  67 # define NO_INDIVIDUAL_EVENT_P(mode) ((mode) & 128)
  68 #else
  69 # define LIO_MODE(mode) mode
  70 # define NO_INDIVIDUAL_EVENT_P(mode) 0
  71 #endif
  72
  73
  74 static int
  75 lio_listio_internal (int mode, struct AIOCB *const list[], int nent,
  76                      struct sigevent *sig)
  77 {
  78   struct sigevent defsigev;
  79   struct requestlist *requests[nent];
  80   int cnt;
  81   volatile unsigned int total = 0;
  82   int result = 0;
  83
  84   if (sig == NULL)
  85     {
  86       defsigev.sigev_notify = SIGEV_NONE;
  87       sig = &defsigev;
  88     }
  89
  90   /* Request the mutex.  */
  91   __pthread_mutex_lock (&__aio_requests_mutex);
  92
  93   /* Now we can enqueue all requests.  Since we already acquired the
  94      mutex the enqueue function need not do this.  */
  95   for (cnt = 0; cnt < nent; ++cnt)
  96     if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)
  97       {
  98         if (NO_INDIVIDUAL_EVENT_P (mode))
  99           list[cnt]->aio_sigevent.sigev_notify = SIGEV_NONE;
 100
 101         requests[cnt] = __aio_enqueue_request ((aiocb_union *) list[cnt],
 102                                                (list[cnt]->aio_lio_opcode
 103                                                 | LIO_OPCODE_BASE));
 104
 105         if (requests[cnt] != NULL)
 106           /* Successfully enqueued.  */
 107           ++total;
 108         else
 109           /* Signal that we've seen an error.  `errno' and the error code
 110              of the aiocb will tell more.  */
 111           result = -1;
 112       }
 113     else
 114       requests[cnt] = NULL;
 115
 116   if (total == 0)
 117     {
 118       /* We don't have anything to do except signalling if we work
 119          asynchronously.  */
 120
 121       /* Release the mutex.  We do this before raising a signal since the
 122          signal handler might do a `siglongjmp' and then the mutex is
 123          locked forever.  */
 124       __pthread_mutex_unlock (&__aio_requests_mutex);
 125
 126       if (LIO_MODE (mode) == LIO_NOWAIT)
 127         __aio_notify_only (sig);
 128
 129       return result;
 130     }
 131   else if (LIO_MODE (mode) == LIO_WAIT)
 132     {
 133 #ifndef DONT_NEED_AIO_MISC_COND
 134       pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
 135       int oldstate;
 136 #endif
 137       struct waitlist waitlist[nent];
 138
 139       total = 0;
 140       for (cnt = 0; cnt < nent; ++cnt)
 141         {
 142           assert (requests[cnt] == NULL || list[cnt] != NULL);
 143
 144           if (requests[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)
 145             {
 146 #ifndef DONT_NEED_AIO_MISC_COND
 147               waitlist[cnt].cond = &cond;
 148 #endif
 149               waitlist[cnt].result = &result;
 150               waitlist[cnt].next = requests[cnt]->waiting;
 151               waitlist[cnt].counterp = &total;
 152               waitlist[cnt].sigevp = NULL;
 153               requests[cnt]->waiting = &waitlist[cnt];
 154               ++total;
 155             }
 156         }
 157
 158 #ifdef DONT_NEED_AIO_MISC_COND
 159       AIO_MISC_WAIT (result, total, NULL, 0);
 160 #else
 161       /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancellation
 162          points we must be careful.  We added entries to the waiting lists
 163          which we must remove.  So defer cancellation for now.  */
 164       pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
 165
 166       while (total > 0)
 167         pthread_cond_wait (&cond, &__aio_requests_mutex);
 168
 169       /* Now it's time to restore the cancellation state.  */
 170       pthread_setcancelstate (oldstate, NULL);
 171
 172       /* Release the conditional variable.  */
 173       if (pthread_cond_destroy (&cond) != 0)
 174         /* This must never happen.  */
 175         abort ();
 176 #endif
 177
 178       /* If any of the I/O requests failed, return -1 and set errno.  */
 179       if (result != 0)
 180         {
 181           __set_errno (result == EINTR ? EINTR : EIO);
 182           result = -1;
 183         }
 184     }
 185   else
 186     {
 187       struct async_waitlist *waitlist;
 188
 189       waitlist = (struct async_waitlist *)
 190         malloc (sizeof (struct async_waitlist)
 191                 + (nent * sizeof (struct waitlist)));
 192
 193       if (waitlist == NULL)
 194         {
 195           __set_errno (EAGAIN);
 196           result = -1;
 197         }
 198       else
 199         {
 200           total = 0;
 201
 202           for (cnt = 0; cnt < nent; ++cnt)
 203             {
 204               assert (requests[cnt] == NULL || list[cnt] != NULL);
 205
 206               if (requests[cnt] != NULL
 207                   && list[cnt]->aio_lio_opcode != LIO_NOP)
 208                 {
 209 #ifndef DONT_NEED_AIO_MISC_COND
 210                   waitlist->list[cnt].cond = NULL;
 211 #endif
 212                   waitlist->list[cnt].result = NULL;
 213                   waitlist->list[cnt].next = requests[cnt]->waiting;
 214                   waitlist->list[cnt].counterp = &waitlist->counter;
 215                   waitlist->list[cnt].sigevp = &waitlist->sigev;
 216                   requests[cnt]->waiting = &waitlist->list[cnt];
 217                   ++total;
 218                 }
 219             }
 220
 221           waitlist->counter = total;
 222           waitlist->sigev = *sig;
 223         }
 224     }
 225
 226   /* Release the mutex.  */
 227   __pthread_mutex_unlock (&__aio_requests_mutex);
 228
 229   return result;
 230 }
 231
 232
 233 #if OTHER_SHLIB_COMPAT (librt, GLIBC_2_1, GLIBC_2_4)
 234 int
 235 attribute_compat_text_section
 236 LIO_LISTIO_OLD (int mode, struct AIOCB *const list[], int nent,
 237                 struct sigevent *sig)
 238 {
 239   /* Check arguments.  */
 240   if (mode != LIO_WAIT && mode != LIO_NOWAIT)
 241     {
 242       __set_errno (EINVAL);
 243       return -1;
 244     }
 245
 246   return lio_listio_internal (mode | LIO_NO_INDIVIDUAL_EVENT, list, nent, sig);
 247 }
 248 compat_symbol (librt, LIO_LISTIO_OLD, LIO_LISTIO, GLIBC_2_1);
 249 # if __WORDSIZE == 64
 250 compat_symbol (librt, LIO_LISTIO_OLD, lio_listio64, GLIBC_2_1);
 251 # endif
 252 #endif /* OTHER_SHLIB_COMPAT */
 253
 254
 255 int
 256 LIO_LISTIO_NEW (int mode, struct AIOCB *const list[], int nent,
 257                 struct sigevent *sig)
 258 {
 259     /* Check arguments.  */
 260   if (mode != LIO_WAIT && mode != LIO_NOWAIT)
 261     {
 262       __set_errno (EINVAL);
 263       return -1;
 264     }
 265
 266   return lio_listio_internal (mode, list, nent, sig);
 267 }
 268
 269 #if PTHREAD_IN_LIBC
 270 versioned_symbol (libc, LIO_LISTIO_NEW, LIO_LISTIO, GLIBC_2_34);
 271 # if __WORDSIZE == 64
 272 versioned_symbol (libc, LIO_LISTIO_NEW, lio_listio64, GLIBC_2_34);
 273 # endif
 274 # if OTHER_SHLIB_COMPAT (librt, GLIBC_2_4, GLIBC_2_34)
 275 compat_symbol (librt, LIO_LISTIO_NEW, LIO_LISTIO, GLIBC_2_4);
 276 #  if __WORDSIZE == 64
 277 compat_symbol (librt, LIO_LISTIO_NEW, lio_listio64, GLIBC_2_4);
 278 #  endif
 279 # endif /* OTHER_SHLIB_COMPAT */
 280 #else /* !PTHREAD_IN_LIBC */
 281 versioned_symbol (librt, LIO_LISTIO_NEW, LIO_LISTIO, GLIBC_2_4);
 282 # if __WORDSIZE == 64
 283 versioned_symbol (librt, LIO_LISTIO_NEW, lio_listio64, GLIBC_2_4);
 284 # endif
 285 #endif /* !PTHREAD_IN_LIBC */