[linux-cifs-client] special files on Services for Unix (SFU) / Interix

[Martin Koeppe]

Hello,

addressing the "missing feature p)" in TODO, I found out,
how special files are stored by SFU/Interix. It's rather simple,
and no extended attributes are needed. You can (theoretically)
create such files with simple DOS commands.

1. FIFOs:
If a file has 0 bytes and has the System attribute set,
Interix considers it as a FIFO special file.

2. symlinks:
You need to put the 8 byte constant 'IntxLNK\001' into a file,
followed by the link target in UCS-2 coding, and set the System
attribute on the file.

3. character device files:
Similar to symlinks (System attribute set),
8 byte constant 'IntxCHR\000' followed
by 2 little endian int64 representing major and minor node.
Overall file size is 24 bytes.

4. block device files:
as character device files, but with constant 'IntxBLK\000'.


Martin