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authorRoland McGrath <roland@hack.frob.com>2014-05-14 13:37:40 -0700
committerRoland McGrath <roland@hack.frob.com>2014-05-14 13:37:40 -0700
commit348f8e8c26178d7e5b7b64c16ab5c1a773916781 (patch)
treee155c8e2bbf1f549127d7b9a40ed33f7926e2b1c /sysdeps/unix/sysv/linux/i386/smp.h
parent5085af05bdfd7b4656abdd79e7da50022e3e1cad (diff)
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Move remaining nptl/sysdeps/unix/sysv/linux/i386/ files.
Diffstat (limited to 'sysdeps/unix/sysv/linux/i386/smp.h')
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1 files changed, 55 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/i386/smp.h b/sysdeps/unix/sysv/linux/i386/smp.h
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+/* Determine whether the host has multiple processors.  Linux version.
+   Copyright (C) 1996-2014 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 = open_not_cancel_2 ("/proc/sys/kernel/version", O_RDONLY);
+      if (__builtin_expect (fd, 0) == -1
+	  || read_not_cancel (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_not_cancel_no_status (fd);
+      cp = u.buf;
+    }
+
+  return strstr (cp, "SMP") != NULL;
+}