Re: interface to ask is a file is hidden

[Alexander Larsson <alexl@redhat.com>]

On Mon, 2008-10-13 at 08:29 +0100, Anton Altaparmakov wrote:
> Hi,
> 
> On 10 Oct 2008, at 22:57, Theodore Tso wrote:
> > Ext3 has no concept of "hidden file".  Niether does ext2, ext4, jfs,
> > xfs, reseirfs, ufs, etc.
> >
> > The only ones that would have that concept is vfat (which supports
> > fat16/fat32), ntfs, nfsv4 and cifs/smbfs.  Even a filesystem which
> > normally has very bad taste, MacOS's HFS, doesn't support the hidden
> > attribute.
> 
> Sorry but you are somewhat wrong: UFS, HFS/HFS+, ZFS, and AFP all  
> support the UF_HIDDEN file flag (in addition to the ones you state  
> above).

FreeBSD seems to have added UF_HIDDEN to struct stat.st_flags back in
2006:
http://updraft3.jp.freebsd.org/cgi/query-pr.cgi?pr=kern/94519

They also have other useful flags like immutable, append only, no dump,
etc that certainly apply to ext3 too (i.e. these are settable with
chattr).

Sounds like a very good idea to me. There is even availible unused space
in the userspace/glibc struct stat to add them, and there seems to be
some in the kernel struct too.

They also have chflags/lchflags/fchflags to change these attributes.