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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <string.h>
  21 #include "pthreadP.h"
  22 #include <lowlevellock.h>
  23
  24
  25 int
  26 attribute_protected
  27 __pthread_getschedparam (
  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   lll_lock (pd->lock, LLL_PRIVATE);
  42
  43   /* The library is responsible for maintaining the values at all
  44      times.  If the user uses a interface other than
  45      pthread_setschedparam to modify the scheduler setting it is not
  46      the library's problem.  In case the descriptor's values have
  47      not yet been retrieved do it now.  */
  48   if ((pd->flags & ATTR_FLAG_SCHED_SET) == 0)
  49     {
  50       if (sched_getparam (pd->tid, &pd->schedparam) != 0)
  51         result = 1;
  52       else
  53         pd->flags |= ATTR_FLAG_SCHED_SET;
  54     }
  55
  56   if ((pd->flags & ATTR_FLAG_POLICY_SET) == 0)
  57     {
  58       pd->schedpolicy = sched_getscheduler (pd->tid);
  59       if (pd->schedpolicy == -1)
  60         result = 1;
  61       else
  62         pd->flags |= ATTR_FLAG_POLICY_SET;
  63     }
  64
  65   if (result == 0)
  66     {
  67       *policy = pd->schedpolicy;
  68       memcpy (param, &pd->schedparam, sizeof (struct sched_param));
  69     }
  70
  71   lll_unlock (pd->lock, LLL_PRIVATE);
  72
  73   return result;
  74 }
  75 strong_alias (__pthread_getschedparam, pthread_getschedparam)