/* Determine whether the host has multiple processors.  Linux version.

   Copyright (C) 1996-2018 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 Library General Public License as

   published by the Free Software Foundation; either version 2 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

   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public

   License along with the GNU C Library; see the file COPYING.LIB.  If

   not, see <http://www.gnu.org/licenses/>.  */

#include <errno.h>

#include <fcntl.h>

#include <string.h>

#include <sys/utsname.h>

#include <not-cancel.h>

/* Test whether the machine has more than one processor.  This is not the

   best test but good enough.  More complicated tests would require `malloc'

   which is not available at that time.  */

static inline int

is_smp_system (void)

{

  union

  {

    struct utsname uts;

    char buf[512];

  } u;

  char *cp;

  /* Try reading the number using `sysctl' first.  */

  if (__uname (&u.uts) == 0)

    cp = u.uts.version;

  else

    {

      /* This was not successful.  Now try reading the /proc filesystem.  */

      int fd = __open64_nocancel ("/proc/sys/kernel/version", O_RDONLY);

      if (__builtin_expect (fd, 0) == -1

	  || __read_nocancel (fd, u.buf, sizeof (u.buf)) <= 0)

	/* This also didn't work.  We give up and say it's a UP machine.  */

	u.buf[0] = '\0';

      __close_nocancel_nostatus (fd);

      cp = u.buf;

    }

  return strstr (cp, "SMP") != NULL;

}