nptl/pthread_setattr_default_np.c

   1 /* Set the default attributes to be used by pthread_create in the process.
   2    Copyright (C) 2013-2015 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 #include <check-cpuset.h>
  25
  26
  27 int
  28 pthread_setattr_default_np (const pthread_attr_t *in)
  29 {
  30   const struct pthread_attr *real_in;
  31   struct pthread_attr attrs;
  32   int ret;
  33
  34   assert (sizeof (*in) >= sizeof (struct pthread_attr));
  35   real_in = (struct pthread_attr *) in;
  36
  37   /* Catch invalid values.  */
  38   int policy = real_in->schedpolicy;
  39   ret = check_sched_policy_attr (policy);
  40   if (ret)
  41     return ret;
  42
  43   const struct sched_param *param = &real_in->schedparam;
  44   if (param->sched_priority > 0)
  45     {
  46       ret = check_sched_priority_attr (param->sched_priority, policy);
  47       if (ret)
  48         return ret;
  49     }
  50
  51   ret = check_cpuset_attr (real_in->cpuset, real_in->cpusetsize);
  52   if (ret)
  53     return ret;
  54
  55   /* stacksize == 0 is fine.  It means that we don't change the current
  56      value.  */
  57   if (real_in->stacksize != 0)
  58     {
  59       ret = check_stacksize_attr (real_in->stacksize);
  60       if (ret)
  61         return ret;
  62     }
  63
  64   /* Having a default stack address is wrong.  */
  65   if (real_in->flags & ATTR_FLAG_STACKADDR)
  66     return EINVAL;
  67
  68   attrs = *real_in;
  69
  70   /* Now take the lock because we start writing into
  71      __default_pthread_attr.  */
  72   lll_lock (__default_pthread_attr_lock, LLL_PRIVATE);
  73
  74   /* Free the cpuset if the input is 0.  Otherwise copy in the cpuset
  75      contents.  */
  76   size_t cpusetsize = attrs.cpusetsize;
  77   if (cpusetsize == 0)
  78     {
  79       free (__default_pthread_attr.cpuset);
  80       __default_pthread_attr.cpuset = NULL;
  81     }
  82   else if (cpusetsize == __default_pthread_attr.cpusetsize)
  83     {
  84       attrs.cpuset = __default_pthread_attr.cpuset;
  85       memcpy (attrs.cpuset, real_in->cpuset, cpusetsize);
  86     }
  87   else
  88     {
  89       /* This may look wrong at first sight, but it isn't.  We're freeing
  90          __default_pthread_attr.cpuset and allocating to attrs.cpuset because
  91          we'll copy over all of attr to __default_pthread_attr later.  */
  92       cpu_set_t *newp = realloc (__default_pthread_attr.cpuset,
  93                                  cpusetsize);
  94
  95       if (newp == NULL)
  96         {
  97           ret = ENOMEM;
  98           goto out;
  99         }
 100
 101       attrs.cpuset = newp;
 102       memcpy (attrs.cpuset, real_in->cpuset, cpusetsize);
 103     }
 104
 105   /* We don't want to accidentally set the default stacksize to zero.  */
 106   if (attrs.stacksize == 0)
 107     attrs.stacksize = __default_pthread_attr.stacksize;
 108   __default_pthread_attr = attrs;
 109
 110  out:
 111   lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE);
 112   return ret;
 113 }