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.

2 files changed, 2 insertions, 1 deletions

diff --git a/libbb/Kbuild.src b/libbb/Kbuild.src
index b298040ac..799f6d01a 100644
--- a/libbb/Kbuild.src
+++ b/libbb/Kbuild.src
@@ -98,6 +98,7 @@ lib-$(CONFIG_PLATFORM_POSIX) += getpty.o
 lib-$(CONFIG_PLATFORM_POSIX) += get_volsize.o
 lib-$(CONFIG_PLATFORM_POSIX) += inet_common.o
 lib-$(CONFIG_PLATFORM_POSIX) += inode_hash.o
+lib-$(CONFIG_FEATURE_EXTRA_FILE_DATA) += inode_hash.o
 lib-$(CONFIG_PLATFORM_POSIX) += kernel_version.o
 lib-$(CONFIG_PLATFORM_POSIX) += login.o
 lib-$(CONFIG_PLATFORM_POSIX) += makedev.o
diff --git a/libbb/copy_file.c b/libbb/copy_file.c
index 299cd7bea..db7a00060 100644
--- a/libbb/copy_file.c
+++ b/libbb/copy_file.c
@@ -105,7 +105,7 @@ int FAST_FUNC copy_file(const char *source, const char *dest, int flags)
                         return -1;
                 }
         } else {
-#if !ENABLE_PLATFORM_MINGW32
+#if !ENABLE_PLATFORM_MINGW32 || ENABLE_FEATURE_EXTRA_FILE_DATA
         /* MinGW does not have inode, and does not use device */
                 if (source_stat.st_dev == dest_stat.st_dev
                  && source_stat.st_ino == dest_stat.st_ino