sysdeps/unix/sysv/linux/check-cpuset.h

   1 /* Validate cpu_set_t values for NPTL.  Linux version.
   2    Copyright (C) 2002-2015 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 <pthread.h>
  20 #include <errno.h>
  21
  22
  23 /* Defined in pthread_setaffinity.c.  */
  24 extern size_t __kernel_cpumask_size attribute_hidden;
  25 extern int __determine_cpumask_size (pid_t tid);
  26
  27 /* Returns 0 if CS and SZ are valid values for the cpuset and cpuset size
  28    respectively.  Otherwise it returns an error number.  */
  29 static inline int
  30 check_cpuset_attr (const cpu_set_t *cs, const size_t sz)
  31 {
  32   if (__kernel_cpumask_size == 0)
  33     {
  34       int res = __determine_cpumask_size (THREAD_SELF->tid);
  35       if (res)
  36         return res;
  37     }
  38
  39   /* Check whether the new bitmask has any bit set beyond the
  40      last one the kernel accepts.  */
  41   for (size_t cnt = __kernel_cpumask_size; cnt < sz; ++cnt)
  42     if (((char *) cs)[cnt] != '\0')
  43       /* Found a nonzero byte.  This means the user request cannot be
  44          fulfilled.  */
  45       return EINVAL;
  46
  47   return 0;
  48 }