libpthread/nptl/pthread_getschedparam.c

   1 /* Copyright (C) 2002, 2003, 2004, 2007 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 attribute_protected
  28 __pthread_getschedparam (
  29      pthread_t threadid,
  30      int *policy,
  31      struct sched_param *param)
  32 {
  33   struct pthread *pd = (struct pthread *) threadid;
  34
  35   /* Make sure the descriptor is valid.  */
  36   if (INVALID_TD_P (pd))
  37     /* Not a valid thread handle.  */
  38     return ESRCH;
  39
  40   int result = 0;
  41
  42   lll_lock (pd->lock, LLL_PRIVATE);
  43
  44   /* The library is responsible for maintaining the values at all
  45      times.  If the user uses a interface other than
  46      pthread_setschedparam to modify the scheduler setting it is not
  47      the library's problem.  In case the descriptor's values have
  48      not yet been retrieved do it now.  */
  49   if ((pd->flags & ATTR_FLAG_SCHED_SET) == 0)
  50     {
  51       if (sched_getparam (pd->tid, &pd->schedparam) != 0)
  52         result = 1;
  53       else
  54         pd->flags |= ATTR_FLAG_SCHED_SET;
  55     }
  56
  57   if ((pd->flags & ATTR_FLAG_POLICY_SET) == 0)
  58     {
  59       pd->schedpolicy = sched_getscheduler (pd->tid);
  60       if (pd->schedpolicy == -1)
  61         result = 1;
  62       else
  63         pd->flags |= ATTR_FLAG_POLICY_SET;
  64     }
  65
  66   if (result == 0)
  67     {
  68       *policy = pd->schedpolicy;
  69       memcpy (param, &pd->schedparam, sizeof (struct sched_param));
  70     }
  71
  72   lll_unlock (pd->lock, LLL_PRIVATE);
  73
  74   return result;
  75 }
  76 strong_alias (__pthread_getschedparam, pthread_getschedparam)