glibc/nptl/pthread_attr_getaffinity.c

/* Copyright (C) 2003-2023 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <pthreadP.h>
#include <string.h>
#include <sysdep.h>
#include <sys/types.h>
#include <sys/param.h>
#include <shlib-compat.h>


int
__pthread_attr_getaffinity_new (const pthread_attr_t *attr, size_t cpusetsize,
				cpu_set_t *cpuset)
{
  const struct pthread_attr *iattr;

  iattr = (const struct pthread_attr *) attr;

  if (iattr->extension != NULL && iattr->extension->cpuset != NULL)
    {
      /* Check whether there are any bits set beyond the limits
	 the user requested.  */
      for (size_t cnt = cpusetsize; cnt < iattr->extension->cpusetsize; ++cnt)
	if (((char *) iattr->extension->cpuset)[cnt] != 0)
	  return EINVAL;

      /* Copy over the cpuset from the thread attribute object.  Limit the copy
	 to the minimum of the source and destination sizes to prevent a buffer
	 overrun.  If the destination is larger, fill the remaining space with
	 zeroes.  */
      void *p = mempcpy (cpuset, iattr->extension->cpuset,
			 MIN (iattr->extension->cpusetsize, cpusetsize));
      if (cpusetsize > iattr->extension->cpusetsize)
	memset (p, '\0', cpusetsize - iattr->extension->cpusetsize);
    }
  else
    /* We have no information.  */
    memset (cpuset, -1, cpusetsize);

  return 0;
}
versioned_symbol (libpthread, __pthread_attr_getaffinity_new,
		  pthread_attr_getaffinity_np, GLIBC_2_34);
#if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_3_4, GLIBC_2_34)
compat_symbol (libpthread, __pthread_attr_getaffinity_new,
	       pthread_attr_getaffinity_np, GLIBC_2_3_4);
#endif


#if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_3_3, GLIBC_2_3_4)
int
__pthread_attr_getaffinity_old (const pthread_attr_t *attr, cpu_set_t *cpuset)
{
  /* The old interface by default assumed a 1024 processor bitmap.  */
  return __pthread_attr_getaffinity_new (attr, 128, cpuset);
}
compat_symbol (libpthread, __pthread_attr_getaffinity_old,
	       pthread_attr_getaffinity_np, GLIBC_2_3_3);
#endif