Re: [avr-gcc-list] Cygwin NTFS hard links?

[David Brown]

> Maybe not the best place to ask this, but... My periodic root-kit scan
flags
> two files that I know are very likely hard linked via Cygwin as file
system
> discrepancies. I'm not concerned; just curious as to how it's done.
> Actually, come to think of it, Cygwin itself must implement a filesystem
> layer to work with these hard links, which makes it a potential security
> hole. For now, though, I'm satisfied that the links are legit
> (arm-elf-c++.exe and arm-elf-gcc-3.40.0-macraigor1). How careful should I
be
> about Cygwin installations?
>

NTFS has always had support for hard links, but Windows has no tools for
using them (just like multiple streams for files on NTFS - a nice idea in
theory, but since there are no tools, the only known use is by a few
viruses).  There might be something in the appropriate windows resource
kits, but otherwise your best tool is the windows port of "ln".

Cygwin does implement a virtual filesystem that can be seen by all cygwin
programs, giving features such as a single root directory, and soft links
(windows does not natively support soft links, although it has a sort of
soft link feature for directories).  That's part of what makes it easy
(easier) to port *nix programs to cygwin rather than native windows, and
also part of why cygwin is a performance hit, especially for file access.