1  /* Set the default attributes to be used by pthread_create in the process.
       2     Copyright (C) 2013-2023 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  #include <shlib-compat.h>
      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  versioned_symbol (libc, __pthread_setattr_default_np,
      85  		  pthread_setattr_default_np, GLIBC_2_34);
      86  #if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_18, GLIBC_2_34)
      87  compat_symbol (libc, __pthread_setattr_default_np,
      88  	       pthread_setattr_default_np, GLIBC_2_18);
      89  #endif
      90  
      91  /* This is placed in the same file as pthread_setattr_default_np
      92     because only this function can trigger allocation of attribute
      93     data.  This way, the function is automatically defined for all the
      94     cases when it is needed in static builds.  */
      95  void
      96  __default_pthread_attr_freeres (void)
      97  {
      98    __pthread_attr_destroy (&__default_pthread_attr.external);
      99  }