nptl/sysdeps/unix/sysv/linux/sparc/sparc32/sem_wait.c

   1 /* sem_wait -- wait on a semaphore.  SPARC version.
   2    Copyright (C) 2003, 2006 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
   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 <sysdep.h>
  23 #include <lowlevellock.h>
  24 #include <internaltypes.h>
  25 #include <semaphore.h>
  26
  27 #include <pthreadP.h>
  28 #include <shlib-compat.h>
  29
  30
  31 int
  32 __new_sem_wait (sem_t *sem)
  33 {
  34   /* First check for cancellation.  */
  35   CANCELLATION_P (THREAD_SELF);
  36
  37   int *futex = (int *) sem;
  38   int err;
  39
  40   do
  41     {
  42       int val;
  43       if (__atomic_is_v9)
  44         val = atomic_decrement_if_positive (futex);
  45       else
  46         {
  47           __sparc32_atomic_do_lock24 (futex + 1);
  48           val = *futex;
  49           if (val > 0)
  50             *futex = val - 1;
  51           __sparc32_atomic_do_unlock24 (futex + 1);
  52         }
  53       if (val > 0)
  54         return 0;
  55
  56       /* Enable asynchronous cancellation.  Required by the standard.  */
  57       int oldtype = __pthread_enable_asynccancel ();
  58
  59       err = lll_futex_wait (futex, 0);
  60
  61       /* Disable asynchronous cancellation.  */
  62       __pthread_disable_asynccancel (oldtype);
  63     }
  64   while (err == 0 || err == -EWOULDBLOCK);
  65
  66   __set_errno (-err);
  67   return -1;
  68 }
  69
  70 versioned_symbol (libpthread, __new_sem_wait, sem_wait, GLIBC_2_1);
  71 #if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1)
  72 strong_alias (__new_sem_wait, __old_sem_wait)
  73 compat_symbol (libpthread, __old_sem_wait, sem_wait, GLIBC_2_0);
  74 #endif