nptl/pthread_getschedparam.c

   1 /* Copyright (C) 2002-2021 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    <https://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 __pthread_getschedparam (pthread_t threadid, int *policy,
  27                          struct sched_param *param)
  28 {
  29   struct pthread *pd = (struct pthread *) threadid;
  30
  31   /* Make sure the descriptor is valid.  */
  32   if (INVALID_TD_P (pd))
  33     /* Not a valid thread handle.  */
  34     return ESRCH;
  35
  36   int result = 0;
  37
  38   /* See CREATE THREAD NOTES in nptl/pthread_create.c.  */
  39   lll_lock (pd->lock, LLL_PRIVATE);
  40
  41   /* The library is responsible for maintaining the values at all
  42      times.  If the user uses an interface other than
  43      pthread_setschedparam to modify the scheduler setting it is not
  44      the library's problem.  In case the descriptor's values have
  45      not yet been retrieved do it now.  */
  46   if ((pd->flags & ATTR_FLAG_SCHED_SET) == 0)
  47     {
  48       if (__sched_getparam (pd->tid, &pd->schedparam) != 0)
  49         result = 1;
  50       else
  51         pd->flags |= ATTR_FLAG_SCHED_SET;
  52     }
  53
  54   if ((pd->flags & ATTR_FLAG_POLICY_SET) == 0)
  55     {
  56       pd->schedpolicy = __sched_getscheduler (pd->tid);
  57       if (pd->schedpolicy == -1)
  58         result = 1;
  59       else
  60         pd->flags |= ATTR_FLAG_POLICY_SET;
  61     }
  62
  63   if (result == 0)
  64     {
  65       *policy = pd->schedpolicy;
  66       memcpy (param, &pd->schedparam, sizeof (struct sched_param));
  67     }
  68
  69   lll_unlock (pd->lock, LLL_PRIVATE);
  70
  71   return result;
  72 }
  73 strong_alias (__pthread_getschedparam, pthread_getschedparam)