nptl/pthread_getschedparam.c

   1 /* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <string.h>
  22 #include "pthreadP.h"
  23 #include <lowlevellock.h>
  24
  25
  26 int
  27 __pthread_getschedparam (threadid, policy, param)
  28      pthread_t threadid;
  29      int *policy;
  30      struct sched_param *param;
  31 {
  32   struct pthread *pd = (struct pthread *) threadid;
  33
  34   /* Make sure the descriptor is valid.  */
  35   if (INVALID_TD_P (pd))
  36     /* Not a valid thread handle.  */
  37     return ESRCH;
  38
  39   int result = 0;
  40
  41   /* We have to handle cancellation in the following code since we are
  42      locking another threads descriptor.  */
  43   pthread_cleanup_push ((void (*) (void *)) lll_unlock_wake_cb, &pd->lock);
  44
  45   lll_lock (pd->lock);
  46
  47   /* The library is responsible for maintaining the values at all
  48      times.  If the user uses a interface other than
  49      pthread_setschedparam to modify the scheduler setting it is not
  50      the library's problem.  In case the descriptor's values have
  51      not yet been retrieved do it now.  */
  52   if ((pd->flags & ATTR_FLAG_SCHED_SET) == 0)
  53     {
  54       if (__sched_getparam (pd->tid, &pd->schedparam) != 0)
  55         result = 1;
  56       else
  57         pd->flags |= ATTR_FLAG_SCHED_SET;
  58     }
  59
  60   if ((pd->flags & ATTR_FLAG_POLICY_SET) == 0)
  61     {
  62       pd->schedpolicy = __sched_getscheduler (pd->tid);
  63       if (pd->schedpolicy == -1)
  64         result = 1;
  65       else
  66         pd->flags |= ATTR_FLAG_POLICY_SET;
  67     }
  68
  69   if (result == 0)
  70     {
  71       *policy = pd->schedpolicy;
  72       memcpy (param, &pd->schedparam, sizeof (struct sched_param));
  73     }
  74
  75   lll_unlock (pd->lock);
  76
  77   pthread_cleanup_pop (0);
  78
  79   return result;
  80 }
  81 strong_alias (__pthread_getschedparam, pthread_getschedparam)