lib/fstat.c

   1 /* fstat() replacement.
   2    Copyright (C) 2011-2024 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    This file is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* If the user's config.h happens to include <sys/stat.h>, let it include only
  18    the system's <sys/stat.h> here, so that orig_fstat doesn't recurse to
  19    rpl_fstat.  */
  20 #define __need_system_sys_stat_h
  21 #include <config.h>
  22
  23 /* Get the original definition of fstat.  It might be defined as a macro.  */
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #undef __need_system_sys_stat_h
  27
  28 #if defined _WIN32 && ! defined __CYGWIN__
  29 # define WINDOWS_NATIVE
  30 #endif
  31
  32 #if !defined WINDOWS_NATIVE
  33
  34 static int
  35 orig_fstat (int fd, struct stat *buf)
  36 {
  37   return fstat (fd, buf);
  38 }
  39
  40 #endif
  41
  42 /* Specification.  */
  43 #ifdef __osf__
  44 /* Write "sys/stat.h" here, not <sys/stat.h>, otherwise OSF/1 5.1 DTK cc
  45    eliminates this include because of the preliminary #include <sys/stat.h>
  46    above.  */
  47 # include "sys/stat.h"
  48 #else
  49 # include <sys/stat.h>
  50 #endif
  51
  52 #include "stat-time.h"
  53
  54 #include <errno.h>
  55 #include <unistd.h>
  56 #ifdef WINDOWS_NATIVE
  57 # define WIN32_LEAN_AND_MEAN
  58 # include <windows.h>
  59 # if GNULIB_MSVC_NOTHROW
  60 #  include "msvc-nothrow.h"
  61 # else
  62 #  include <io.h>
  63 # endif
  64 # include "stat-w32.h"
  65 #endif
  66
  67 int
  68 rpl_fstat (int fd, struct stat *buf)
  69 {
  70 #if REPLACE_FCHDIR && REPLACE_OPEN_DIRECTORY
  71   /* Handle the case when rpl_open() used a dummy file descriptor to work
  72      around an open() that can't normally visit directories.  */
  73   const char *name = _gl_directory_name (fd);
  74   if (name != NULL)
  75     return stat (name, buf);
  76 #endif
  77
  78 #ifdef WINDOWS_NATIVE
  79   /* Fill the fields ourselves, because the original fstat function returns
  80      values for st_atime, st_mtime, st_ctime that depend on the current time
  81      zone.  See
  82      <https://lists.gnu.org/r/bug-gnulib/2017-04/msg00134.html>  */
  83   HANDLE h = (HANDLE) _get_osfhandle (fd);
  84
  85   if (h == INVALID_HANDLE_VALUE)
  86     {
  87       errno = EBADF;
  88       return -1;
  89     }
  90   return _gl_fstat_by_handle (h, NULL, buf);
  91 #else
  92   return stat_time_normalize (orig_fstat (fd, buf), buf);
  93 #endif
  94 }