nptl/pthread_setattr_default_np.c

   1 /* Set the default attributes to be used by pthread_create in the process.
   2    Copyright (C) 2013-2018 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    <http://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   struct pthread_attr attrs;
  30   int ret;
  31
  32   real_in = (struct pthread_attr *) in;
  33
  34   /* Catch invalid values.  */
  35   int policy = real_in->schedpolicy;
  36   ret = check_sched_policy_attr (policy);
  37   if (ret)
  38     return ret;
  39
  40   const struct sched_param *param = &real_in->schedparam;
  41   if (param->sched_priority > 0)
  42     {
  43       ret = check_sched_priority_attr (param->sched_priority, policy);
  44       if (ret)
  45         return ret;
  46     }
  47
  48   /* stacksize == 0 is fine.  It means that we don't change the current
  49      value.  */
  50   if (real_in->stacksize != 0)
  51     {
  52       ret = check_stacksize_attr (real_in->stacksize);
  53       if (ret)
  54         return ret;
  55     }
  56
  57   /* Having a default stack address is wrong.  */
  58   if (real_in->flags & ATTR_FLAG_STACKADDR)
  59     return EINVAL;
  60
  61   attrs = *real_in;
  62
  63   /* Now take the lock because we start writing into
  64      __default_pthread_attr.  */
  65   lll_lock (__default_pthread_attr_lock, LLL_PRIVATE);
  66
  67   /* Free the cpuset if the input is 0.  Otherwise copy in the cpuset
  68      contents.  */
  69   size_t cpusetsize = attrs.cpusetsize;
  70   if (cpusetsize == 0)
  71     {
  72       free (__default_pthread_attr.cpuset);
  73       __default_pthread_attr.cpuset = NULL;
  74     }
  75   else if (cpusetsize == __default_pthread_attr.cpusetsize)
  76     {
  77       attrs.cpuset = __default_pthread_attr.cpuset;
  78       memcpy (attrs.cpuset, real_in->cpuset, cpusetsize);
  79     }
  80   else
  81     {
  82       /* This may look wrong at first sight, but it isn't.  We're freeing
  83          __default_pthread_attr.cpuset and allocating to attrs.cpuset because
  84          we'll copy over all of attr to __default_pthread_attr later.  */
  85       cpu_set_t *newp = realloc (__default_pthread_attr.cpuset,
  86                                  cpusetsize);
  87
  88       if (newp == NULL)
  89         {
  90           ret = ENOMEM;
  91           goto out;
  92         }
  93
  94       attrs.cpuset = newp;
  95       memcpy (attrs.cpuset, real_in->cpuset, cpusetsize);
  96     }
  97
  98   /* We don't want to accidentally set the default stacksize to zero.  */
  99   if (attrs.stacksize == 0)
 100     attrs.stacksize = __default_pthread_attr.stacksize;
 101   __default_pthread_attr = attrs;
 102
 103  out:
 104   lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE);
 105   return ret;
 106 }