sysdeps/unix/sysv/linux/sched_setaffinity.c

   1 /* Copyright (C) 2002-2014 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    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <sched.h>
  20 #include <string.h>
  21 #include <sysdep.h>
  22 #include <unistd.h>
  23 #include <sys/types.h>
  24 #include <shlib-compat.h>
  25 #include <alloca.h>
  26
  27
  28 #ifdef __NR_sched_setaffinity
  29 static size_t __kernel_cpumask_size;
  30
  31
  32 int
  33 __sched_setaffinity_new (pid_t pid, size_t cpusetsize, const cpu_set_t *cpuset)
  34 {
  35   if (__builtin_expect (__kernel_cpumask_size == 0, 0))
  36     {
  37       INTERNAL_SYSCALL_DECL (err);
  38       int res;
  39
  40       size_t psize = 128;
  41       void *p = alloca (psize);
  42
  43       while (res = INTERNAL_SYSCALL (sched_getaffinity, err, 3, getpid (),
  44                                      psize, p),
  45              INTERNAL_SYSCALL_ERROR_P (res, err)
  46              && INTERNAL_SYSCALL_ERRNO (res, err) == EINVAL)
  47         p = extend_alloca (p, psize, 2 * psize);
  48
  49       if (res == 0 || INTERNAL_SYSCALL_ERROR_P (res, err))
  50         {
  51           __set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
  52           return -1;
  53         }
  54
  55       __kernel_cpumask_size = res;
  56     }
  57
  58   /* We now know the size of the kernel cpumask_t.  Make sure the user
  59      does not request to set a bit beyond that.  */
  60   for (size_t cnt = __kernel_cpumask_size; cnt < cpusetsize; ++cnt)
  61     if (((char *) cpuset)[cnt] != '\0')
  62       {
  63         /* Found a nonzero byte.  This means the user request cannot be
  64            fulfilled.  */
  65         __set_errno (EINVAL);
  66         return -1;
  67       }
  68
  69   int result = INLINE_SYSCALL (sched_setaffinity, 3, pid, cpusetsize, cpuset);
  70
  71 #ifdef RESET_VGETCPU_CACHE
  72   if (result != -1)
  73     RESET_VGETCPU_CACHE ();
  74 #endif
  75
  76   return result;
  77 }
  78 versioned_symbol (libc, __sched_setaffinity_new, sched_setaffinity,
  79                   GLIBC_2_3_4);
  80
  81
  82 # if SHLIB_COMPAT (libc, GLIBC_2_3_3, GLIBC_2_3_4)
  83 int
  84 attribute_compat_text_section
  85 __sched_setaffinity_old (pid_t pid, const cpu_set_t *cpuset)
  86 {
  87   /* The old interface by default assumed a 1024 processor bitmap.  */
  88   return __sched_setaffinity_new (pid, 128, cpuset);
  89 }
  90 compat_symbol (libc, __sched_setaffinity_old, sched_setaffinity, GLIBC_2_3_3);
  91 # endif
  92 #else
  93 # include <posix/sched_setaffinity.c>
  94 #endif