sysdeps/unix/sysv/linux/x86/gettimeofday.c

   1 /* gettimeofday - get the time.  Linux/x86 version.
   2    Copyright (C) 2015 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 <sys/time.h>
  20
  21 #ifdef SHARED
  22
  23 # include <dl-vdso.h>
  24 # include <errno.h>
  25
  26 static int
  27 __gettimeofday_syscall (struct timeval *tv, struct timezone *tz)
  28 {
  29   return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
  30 }
  31
  32 void *gettimeofday_ifunc (void) __asm__ ("__gettimeofday");
  33
  34 void *
  35 gettimeofday_ifunc (void)
  36 {
  37   PREPARE_VERSION_KNOWN (linux26, LINUX_2_6);
  38
  39   /* If the vDSO is not available we fall back to syscall.  */
  40   return (_dl_vdso_vsym ("__vdso_gettimeofday", &linux26)
  41           ?: (void*) (&__gettimeofday_syscall));
  42 }
  43 asm (".type __gettimeofday, %gnu_indirect_function");
  44
  45 libc_ifunc_hidden_def(__gettimeofday)
  46
  47 #else
  48
  49 # include <sysdep.h>
  50 # include <errno.h>
  51
  52 int
  53 __gettimeofday (struct timeval *tv, struct timezone *tz)
  54 {
  55   return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
  56 }
  57 libc_hidden_def (__gettimeofday)
  58
  59 #endif
  60 weak_alias (__gettimeofday, gettimeofday)
  61 libc_hidden_weak (gettimeofday)