win32: make stat(2) fetch additional metadata

Modify the WIN32 implementation of stat(2) to fetch inode number,
device id and number of hardlinks.  This requires opening a handle
to the target file so it will be slower.

A number of features can be enabled or start to work:

- tar can detect if an archive is being stored in itself;
- find can support the -inum and -links options;
- ls can display inode numbers;
- diff can detect attempts to compare a file with itself;
- du has better support for hardlinked files;
- cp can detect attempts to copy a file over itself.

1 files changed, 10 insertions, 0 deletions

diff --git a/Config.in b/Config.in
index 0318a6aff..9f8d4bf7c 100644
--- a/Config.in
+++ b/Config.in
@@ -463,6 +463,16 @@ config FEATURE_EURO
         requires the OEM code page to be 858.  If the OEM code page of
         the console is 850 when BusyBox starts it's changed to 858.
 
+config FEATURE_EXTRA_FILE_DATA
+        bool "Read additional file metadata (1.3 kb)"
+        default y
+        depends on PLATFORM_MINGW32
+        help
+        Read additional file metadata: device id, inode number and number
+        of hard links.  This may slow down some file operations but it
+        permits extra features such as warning of attempts to copy a file
+        onto itself or to store a tar archive in itself.
+
 comment 'Build Options'
 
 config STATIC