support/support_path_support_time64.c

   1 /* Check if path supports 64-bit time interfaces.
   2    Copyright (C) 2021-2022 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 <fcntl.h>
  20 #include <unistd.h>
  21 #include <support/check.h>
  22 #include <support/support.h>
  23 #include <sys/stat.h>
  24 #ifdef __linux__
  25 #include <sysdep.h>
  26 #endif
  27
  28 #ifdef __linux__
  29 static int
  30 utimesat_call (const char *path, const struct __timespec64 tsp[2])
  31 {
  32 # ifndef __NR_utimensat_time64
  33 #  define __NR_utimensat_time64 __NR_utimensat
  34 # endif
  35   return syscall (__NR_utimensat_time64, AT_FDCWD, path, &tsp[0], 0);
  36 }
  37 #endif
  38
  39 bool
  40 support_path_support_time64_value (const char *path, int64_t at, int64_t mt)
  41 {
  42 #ifdef __linux__
  43   /* Obtain the original timestamps to restore at the end.  */
  44   struct statx ostx;
  45   TEST_VERIFY_EXIT (statx (AT_FDCWD, path, 0, STATX_BASIC_STATS, &ostx) == 0);
  46
  47   const struct __timespec64 tsp[] = { { at, 0 }, { mt, 0 } };
  48
  49   /* Return is kernel does not support __NR_utimensat_time64.  */
  50   if (utimesat_call (path, tsp) == -1)
  51     return false;
  52
  53   /* Verify if the last access and last modification time match the ones
  54      obtained with statx.  */
  55   struct statx stx;
  56   TEST_VERIFY_EXIT (statx (AT_FDCWD, path, 0, STATX_BASIC_STATS, &stx) == 0);
  57
  58   bool support = stx.stx_atime.tv_sec == tsp[0].tv_sec
  59                  && stx.stx_mtime.tv_sec == tsp[1].tv_sec;
  60
  61   /* Reset to original timestamps.  */
  62   const struct __timespec64 otsp[] =
  63   {
  64     { ostx.stx_atime.tv_sec, ostx.stx_atime.tv_nsec },
  65     { ostx.stx_mtime.tv_sec, ostx.stx_mtime.tv_nsec },
  66   };
  67   TEST_VERIFY_EXIT (utimesat_call (path, otsp) == 0);
  68
  69   return support;
  70 #else
  71   return true;
  72 #endif
  73 }