diff options
Diffstat (limited to 'libpthread/nptl/sysdeps/unix/sysv/linux/sem_timedwait.c')
| -rw-r--r-- | libpthread/nptl/sysdeps/unix/sysv/linux/sem_timedwait.c | 97 | 
1 files changed, 97 insertions, 0 deletions
| diff --git a/libpthread/nptl/sysdeps/unix/sysv/linux/sem_timedwait.c b/libpthread/nptl/sysdeps/unix/sysv/linux/sem_timedwait.c new file mode 100644 index 000000000..79b11948c --- /dev/null +++ b/libpthread/nptl/sysdeps/unix/sysv/linux/sem_timedwait.c @@ -0,0 +1,97 @@ +/* sem_timedwait -- wait on a semaphore.  Generic futex-using version. +   Copyright (C) 2003 Free Software Foundation, Inc. +   This file is part of the GNU C Library. +   Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003. + +   The GNU C Library is free software; you can redistribute it and/or +   modify it under the terms of the GNU Lesser General Public +   License as published by the Free Software Foundation; either +   version 2.1 of the License, or (at your option) any later version. + +   The GNU C Library is distributed in the hope that it will be useful, +   but WITHOUT ANY WARRANTY; without even the implied warranty of +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU +   Lesser General Public License for more details. + +   You should have received a copy of the GNU Lesser General Public +   License along with the GNU C Library; if not, write to the Free +   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA +   02111-1307 USA.  */ + +#include <errno.h> +#include <sysdep.h> +#include <lowlevellock.h> +#include <internaltypes.h> +#include <semaphore.h> +#include <pthreadP.h> + + +int +sem_timedwait (sem_t *sem, const struct timespec *abstime) +{ +  /* First check for cancellation.  */ +  CANCELLATION_P (THREAD_SELF); + +  int *futex = (int *) sem; +  int val; +  int err; + +  if (*futex > 0) +    { +      val = atomic_decrement_if_positive (futex); +      if (val > 0) +	return 0; +    } + +  err = -EINVAL; +  if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) +    goto error_return; + +  do +    { +      struct timeval tv; +      struct timespec rt; +      int sec, nsec; + +      /* Get the current time.  */ +      gettimeofday (&tv, NULL); + +      /* Compute relative timeout.  */ +      sec = abstime->tv_sec - tv.tv_sec; +      nsec = abstime->tv_nsec - tv.tv_usec * 1000; +      if (nsec < 0) +	{ +	  nsec += 1000000000; +	  --sec; +	} + +      /* Already timed out?  */ +      err = -ETIMEDOUT; +      if (sec < 0) +	goto error_return; + +      /* Do wait.  */ +      rt.tv_sec = sec; +      rt.tv_nsec = nsec; + +      /* Enable asynchronous cancellation.  Required by the standard.  */ +      int oldtype = __pthread_enable_asynccancel (); + +      err = lll_futex_timed_wait (futex, 0, &rt); + +      /* Disable asynchronous cancellation.  */ +      __pthread_disable_asynccancel (oldtype); + +      if (err != 0 && err != -EWOULDBLOCK) +	goto error_return; + +      val = atomic_decrement_if_positive (futex); +    } +  while (val <= 0); + +  return 0; + + error_return: +  __set_errno (-err); +  return -1; +} | 
