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

   1 /* time -- Get number of seconds since Epoch.  Linux/x86 version.
   2    Copyright (C) 2015-2019 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <time.h>
  20
  21 #ifdef SHARED
  22
  23 #include <dl-vdso.h>
  24 #include <errno.h>
  25
  26 static time_t
  27 __time_syscall (time_t *t)
  28 {
  29   INTERNAL_SYSCALL_DECL (err);
  30   return INTERNAL_SYSCALL (time, err, 1, t);
  31 }
  32
  33 # ifndef time_type
  34 /* The i386 time.c includes this file with a defined time_type macro.
  35    For x86_64 we have to define it to time as the internal symbol is the
  36    ifunc'ed one.  */
  37 #  define time_type time
  38 # endif
  39
  40 #undef INIT_ARCH
  41 #define INIT_ARCH() PREPARE_VERSION_KNOWN (linux26, LINUX_2_6);
  42 /* If the vDSO is not available we fall back on the syscall.  */
  43 libc_ifunc_hidden (time_type, time,
  44                    (_dl_vdso_vsym ("__vdso_time", &linux26)
  45                     ?:  &__time_syscall))
  46 libc_hidden_def (time)
  47
  48 #else
  49
  50 # include <sysdep.h>
  51
  52 time_t
  53 time (time_t *t)
  54 {
  55   INTERNAL_SYSCALL_DECL (err);
  56   return INTERNAL_SYSCALL (time, err, 1, t);
  57 }
  58
  59 #endif