nptl/pthread_setattr_default_np.c

   1 /* Set the default attributes to be used by pthread_create in the process.
   2    Copyright (C) 2013-2020 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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 <stdlib.h>
  21 #include <pthreadP.h>
  22 #include <string.h>
  23
  24
  25 int
  26 pthread_setattr_default_np (const pthread_attr_t *in)
  27 {
  28   const struct pthread_attr *real_in;
  29   int ret;
  30
  31   real_in = (struct pthread_attr *) in;
  32
  33   /* Catch invalid values.  */
  34   int policy = real_in->schedpolicy;
  35   ret = check_sched_policy_attr (policy);
  36   if (ret)
  37     return ret;
  38
  39   const struct sched_param *param = &real_in->schedparam;
  40   if (param->sched_priority > 0)
  41     {
  42       ret = check_sched_priority_attr (param->sched_priority, policy);
  43       if (ret)
  44         return ret;
  45     }
  46
  47   /* stacksize == 0 is fine.  It means that we don't change the current
  48      value.  */
  49   if (real_in->stacksize != 0)
  50     {
  51       ret = check_stacksize_attr (real_in->stacksize);
  52       if (ret)
  53         return ret;
  54     }
  55
  56   /* Having a default stack address is wrong.  */
  57   if (real_in->flags & ATTR_FLAG_STACKADDR)
  58     return EINVAL;
  59
  60   union pthread_attr_transparent temp;
  61   ret = __pthread_attr_copy (&temp.external, in);
  62   if (ret != 0)
  63     return ret;
  64
  65   /* Now take the lock because we start accessing
  66      __default_pthread_attr.  */
  67   lll_lock (__default_pthread_attr_lock, LLL_PRIVATE);
  68
  69   /* Preserve the previous stack size (see above).  */
  70   if (temp.internal.stacksize == 0)
  71     temp.internal.stacksize = __default_pthread_attr.internal.stacksize;
  72
  73   /* Destroy the old attribute structure because it will be
  74      overwritten.  */
  75   __pthread_attr_destroy (&__default_pthread_attr.external);
  76
  77   /* __default_pthread_attr takes ownership, so do not free
  78      attrs.internal after this point.  */
  79   __default_pthread_attr = temp;
  80
  81   lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE);
  82   return ret;
  83 }
  84
  85 /* This is placed in the same file as pthread_setattr_default_np
  86    because only this function can trigger allocation of attribute
  87    data.  This way, the function is automatically defined for all the
  88    cases when it is needed in static builds.  */
  89 void
  90 __default_pthread_attr_freeres (void)
  91 {
  92   __pthread_attr_destroy (&__default_pthread_attr.external);
  93 }