sysdeps/unix/sysv/linux/sched_setaffinity.c

   1 /* Copyright (C) 2002, 2003, 2004, 2005, 2007
   2    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 <errno.h>
  20 #include <sched.h>
  21 #include <string.h>
  22 #include <sysdep.h>
  23 #include <unistd.h>
  24 #include <sys/types.h>
  25 #include <shlib-compat.h>
  26 #include <alloca.h>
  27
  28
  29 #ifdef __NR_sched_setaffinity
  30 static size_t __kernel_cpumask_size;
  31
  32
  33 int
  34 __sched_setaffinity_new (pid_t pid, size_t cpusetsize, const cpu_set_t *cpuset)
  35 {
  36   if (__builtin_expect (__kernel_cpumask_size == 0, 0))
  37     {
  38       INTERNAL_SYSCALL_DECL (err);
  39       int res;
  40
  41       size_t psize = 128;
  42       void *p = alloca (psize);
  43
  44       while (res = INTERNAL_SYSCALL (sched_getaffinity, err, 3, getpid (),
  45                                      psize, p),
  46              INTERNAL_SYSCALL_ERROR_P (res, err)
  47              && INTERNAL_SYSCALL_ERRNO (res, err) == EINVAL)
  48         p = extend_alloca (p, psize, 2 * psize);
  49
  50       if (res == 0 || INTERNAL_SYSCALL_ERROR_P (res, err))
  51         {
  52           __set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
  53           return -1;
  54         }
  55
  56       __kernel_cpumask_size = res;
  57     }
  58
  59   /* We now know the size of the kernel cpumask_t.  Make sure the user
  60      does not request to set a bit beyond that.  */
  61   for (size_t cnt = __kernel_cpumask_size; cnt < cpusetsize; ++cnt)
  62     if (((char *) cpuset)[cnt] != '\0')
  63       {
  64         /* Found a nonzero byte.  This means the user request cannot be
  65            fulfilled.  */
  66         __set_errno (EINVAL);
  67         return -1;
  68       }
  69
  70   int result = INLINE_SYSCALL (sched_setaffinity, 3, pid, cpusetsize, cpuset);
  71
  72 #ifdef RESET_VGETCPU_CACHE
  73   if (result != -1)
  74     RESET_VGETCPU_CACHE ();
  75 #endif
  76
  77   return result;
  78 }
  79 versioned_symbol (libc, __sched_setaffinity_new, sched_setaffinity,
  80                   GLIBC_2_3_4);
  81
  82
  83 # if SHLIB_COMPAT (libc, GLIBC_2_3_3, GLIBC_2_3_4)
  84 int
  85 attribute_compat_text_section
  86 __sched_setaffinity_old (pid_t pid, const cpu_set_t *cpuset)
  87 {
  88   /* The old interface by default assumed a 1024 processor bitmap.  */
  89   return __sched_setaffinity_new (pid, 128, cpuset);
  90 }
  91 compat_symbol (libc, __sched_setaffinity_old, sched_setaffinity, GLIBC_2_3_3);
  92 # endif
  93 #else
  94 # include <posix/sched_setaffinity.c>
  95 #endif