nptl/pthread_setattr_default_np.c

   1 /* Set the default attributes to be used by pthread_create in the process.
   2    Copyright (C) 2013-2017 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 <assert.h>
  23 #include <string.h>
  24
  25
  26 int
  27 pthread_setattr_default_np (const pthread_attr_t *in)
  28 {
  29   const struct pthread_attr *real_in;
  30   struct pthread_attr attrs;
  31   int ret;
  32
  33   assert (sizeof (*in) >= sizeof (struct pthread_attr));
  34   real_in = (struct pthread_attr *) in;
  35
  36   /* Catch invalid values.  */
  37   int policy = real_in->schedpolicy;
  38   ret = check_sched_policy_attr (policy);
  39   if (ret)
  40     return ret;
  41
  42   const struct sched_param *param = &real_in->schedparam;
  43   if (param->sched_priority > 0)
  44     {
  45       ret = check_sched_priority_attr (param->sched_priority, policy);
  46       if (ret)
  47         return ret;
  48     }
  49
  50   /* stacksize == 0 is fine.  It means that we don't change the current
  51      value.  */
  52   if (real_in->stacksize != 0)
  53     {
  54       ret = check_stacksize_attr (real_in->stacksize);
  55       if (ret)
  56         return ret;
  57     }
  58
  59   /* Having a default stack address is wrong.  */
  60   if (real_in->flags & ATTR_FLAG_STACKADDR)
  61     return EINVAL;
  62
  63   attrs = *real_in;
  64
  65   /* Now take the lock because we start writing into
  66      __default_pthread_attr.  */
  67   lll_lock (__default_pthread_attr_lock, LLL_PRIVATE);
  68
  69   /* Free the cpuset if the input is 0.  Otherwise copy in the cpuset
  70      contents.  */
  71   size_t cpusetsize = attrs.cpusetsize;
  72   if (cpusetsize == 0)
  73     {
  74       free (__default_pthread_attr.cpuset);
  75       __default_pthread_attr.cpuset = NULL;
  76     }
  77   else if (cpusetsize == __default_pthread_attr.cpusetsize)
  78     {
  79       attrs.cpuset = __default_pthread_attr.cpuset;
  80       memcpy (attrs.cpuset, real_in->cpuset, cpusetsize);
  81     }
  82   else
  83     {
  84       /* This may look wrong at first sight, but it isn't.  We're freeing
  85          __default_pthread_attr.cpuset and allocating to attrs.cpuset because
  86          we'll copy over all of attr to __default_pthread_attr later.  */
  87       cpu_set_t *newp = realloc (__default_pthread_attr.cpuset,
  88                                  cpusetsize);
  89
  90       if (newp == NULL)
  91         {
  92           ret = ENOMEM;
  93           goto out;
  94         }
  95
  96       attrs.cpuset = newp;
  97       memcpy (attrs.cpuset, real_in->cpuset, cpusetsize);
  98     }
  99
 100   /* We don't want to accidentally set the default stacksize to zero.  */
 101   if (attrs.stacksize == 0)
 102     attrs.stacksize = __default_pthread_attr.stacksize;
 103   __default_pthread_attr = attrs;
 104
 105  out:
 106   lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE);
 107   return ret;
 108 }