nptl/pthread_attr_getaffinity.c

   1 /* Copyright (C) 2003-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <pthreadP.h>
  20 #include <string.h>
  21 #include <sysdep.h>
  22 #include <sys/types.h>
  23 #include <sys/param.h>
  24 #include <shlib-compat.h>
  25
  26
  27 int
  28 __pthread_attr_getaffinity_new (const pthread_attr_t *attr, size_t cpusetsize,
  29                                 cpu_set_t *cpuset)
  30 {
  31   const struct pthread_attr *iattr;
  32
  33   iattr = (const struct pthread_attr *) attr;
  34
  35   if (iattr->extension != NULL && iattr->extension->cpuset != NULL)
  36     {
  37       /* Check whether there are any bits set beyond the limits
  38          the user requested.  */
  39       for (size_t cnt = cpusetsize; cnt < iattr->extension->cpusetsize; ++cnt)
  40         if (((char *) iattr->extension->cpuset)[cnt] != 0)
  41           return EINVAL;
  42
  43       /* Copy over the cpuset from the thread attribute object.  Limit the copy
  44          to the minimum of the source and destination sizes to prevent a buffer
  45          overrun.  If the destination is larger, fill the remaining space with
  46          zeroes.  */
  47       void *p = mempcpy (cpuset, iattr->extension->cpuset,
  48                          MIN (iattr->extension->cpusetsize, cpusetsize));
  49       if (cpusetsize > iattr->extension->cpusetsize)
  50         memset (p, '\0', cpusetsize - iattr->extension->cpusetsize);
  51     }
  52   else
  53     /* We have no information.  */
  54     memset (cpuset, -1, cpusetsize);
  55
  56   return 0;
  57 }
  58 versioned_symbol (libpthread, __pthread_attr_getaffinity_new,
  59                   pthread_attr_getaffinity_np, GLIBC_2_34);
  60 #if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_3_4, GLIBC_2_34)
  61 compat_symbol (libpthread, __pthread_attr_getaffinity_new,
  62                pthread_attr_getaffinity_np, GLIBC_2_3_4);
  63 #endif
  64
  65
  66 #if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_3_3, GLIBC_2_3_4)
  67 int
  68 __pthread_attr_getaffinity_old (const pthread_attr_t *attr, cpu_set_t *cpuset)
  69 {
  70   /* The old interface by default assumed a 1024 processor bitmap.  */
  71   return __pthread_attr_getaffinity_new (attr, 128, cpuset);
  72 }
  73 compat_symbol (libpthread, __pthread_attr_getaffinity_old,
  74                pthread_attr_getaffinity_np, GLIBC_2_3_3);
  75 #endif