Anand Sivaram wrote:
I dont think you could do that in filesystem level, since when 'w' permission is given the user could create both files and directories, but without 'w' permission the user cant do both. May be you could give readonly permission to all directories except one where this user could create any type of files including directories and normal files.
POSIX won't allow it, but another layer could (a virtual filesystem, mandatory access control systems, ...)
The reason nobody seems to care very much is that determining the file type is very difficult to do reliably. Obviously filename extensions are useless, but format signatures can also be easily faked. Even the human eye can be fooled by some steganographic contents, and a directory structure could take the form of an archive.
Restricting file types to a directory is just not something you usually do. But maybe there are special use cases.
-t