nptl/pthread_getschedparam.c

   1 /* Copyright (C) 2002-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <string.h>
  20 #include "pthreadP.h"
  21 #include <lowlevellock.h>
  22
  23
  24 int
  25 __pthread_getschedparam (pthread_t threadid, int *policy,
  26                          struct sched_param *param)
  27 {
  28   struct pthread *pd = (struct pthread *) threadid;
  29
  30   /* Make sure the descriptor is valid.  */
  31   if (INVALID_TD_P (pd))
  32     /* Not a valid thread handle.  */
  33     return ESRCH;
  34
  35   int result = 0;
  36
  37   /* See CREATE THREAD NOTES in nptl/pthread_create.c.  */
  38   lll_lock (pd->lock, LLL_PRIVATE);
  39
  40   /* The library is responsible for maintaining the values at all
  41      times.  If the user uses an interface other than
  42      pthread_setschedparam to modify the scheduler setting it is not
  43      the library's problem.  In case the descriptor's values have
  44      not yet been retrieved do it now.  */
  45   if ((pd->flags & ATTR_FLAG_SCHED_SET) == 0)
  46     {
  47       if (__sched_getparam (pd->tid, &pd->schedparam) != 0)
  48         result = 1;
  49       else
  50         pd->flags |= ATTR_FLAG_SCHED_SET;
  51     }
  52
  53   if ((pd->flags & ATTR_FLAG_POLICY_SET) == 0)
  54     {
  55       pd->schedpolicy = __sched_getscheduler (pd->tid);
  56       if (pd->schedpolicy == -1)
  57         result = 1;
  58       else
  59         pd->flags |= ATTR_FLAG_POLICY_SET;
  60     }
  61
  62   if (result == 0)
  63     {
  64       *policy = pd->schedpolicy;
  65       memcpy (param, &pd->schedparam, sizeof (struct sched_param));
  66     }
  67
  68   lll_unlock (pd->lock, LLL_PRIVATE);
  69
  70   return result;
  71 }
  72 libc_hidden_def (__pthread_getschedparam)
  73 strong_alias (__pthread_getschedparam, pthread_getschedparam)