nptl/pthread_setattr_default_np.c

   1 /* Set the default attributes to be used by pthread_create in the process.
   2    Copyright (C) 2013 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 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   assert (sizeof (*in) >= sizeof (struct pthread_attr));
  33   real_in = (struct pthread_attr *) in;
  34
  35   /* Catch invalid values.  */
  36   int policy = real_in->schedpolicy;
  37   ret = check_sched_policy_attr (policy);
  38   if (ret)
  39     return ret;
  40
  41   const struct sched_param *param = &real_in->schedparam;
  42   if (param->sched_priority > 0)
  43     {
  44       ret = check_sched_priority_attr (param->sched_priority, policy);
  45       if (ret)
  46         return ret;
  47     }
  48
  49   ret = check_cpuset_attr (real_in->cpuset, real_in->cpusetsize);
  50   if (ret)
  51     return ret;
  52
  53   /* stacksize == 0 is fine.  It means that we don't change the current
  54      value.  */
  55   if (real_in->stacksize != 0)
  56     {
  57       ret = check_stacksize_attr (real_in->stacksize);
  58       if (ret)
  59         return ret;
  60     }
  61
  62   /* Having a default stack address is wrong.  */
  63   if (real_in->flags & ATTR_FLAG_STACKADDR)
  64     return EINVAL;
  65
  66   attrs = *real_in;
  67
  68   /* Now take the lock because we start writing into
  69      __default_pthread_attr.  */
  70   lll_lock (__default_pthread_attr_lock, LLL_PRIVATE);
  71
  72   /* Free the cpuset if the input is 0.  Otherwise copy in the cpuset
  73      contents.  */
  74   size_t cpusetsize = attrs.cpusetsize;
  75   if (cpusetsize == 0)
  76     {
  77       free (__default_pthread_attr.cpuset);
  78       __default_pthread_attr.cpuset = NULL;
  79     }
  80   else if (cpusetsize == __default_pthread_attr.cpusetsize)
  81     {
  82       attrs.cpuset = __default_pthread_attr.cpuset;
  83       memcpy (attrs.cpuset, real_in->cpuset, cpusetsize);
  84     }
  85   else
  86     {
  87       /* This may look wrong at first sight, but it isn't.  We're freeing
  88          __default_pthread_attr.cpuset and allocating to attrs.cpuset because
  89          we'll copy over all of attr to __default_pthread_attr later.  */
  90       cpu_set_t *newp = realloc (__default_pthread_attr.cpuset,
  91                                  cpusetsize);
  92
  93       if (newp == NULL)
  94         {
  95           ret = ENOMEM;
  96           goto out;
  97         }
  98
  99       attrs.cpuset = newp;
 100       memcpy (attrs.cpuset, real_in->cpuset, cpusetsize);
 101     }
 102
 103   /* We don't want to accidentally set the default stacksize to zero.  */
 104   if (attrs.stacksize == 0)
 105     attrs.stacksize = __default_pthread_attr.stacksize;
 106   __default_pthread_attr = attrs;
 107
 108  out:
 109   lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE);
 110   return ret;
 111 }