The existing implementation of NameSpace implicitly assumes that a
FileSystem with a directory at the top will be mounted at the root
mount point "/" of the NameSpace. If this is not the case, then
Stat("/") will fail even if ReadDir("/") succeedes. This is unexpected
behavior which breaks directory traversal routines (eg. http.FileServer).
This CL adds an unexported implementation of FileSystem called emptyVFS
that emulates an empty directory and adds a NewNameSpace() function that
binds emptyVFS to "/" so that unexpected behavior does not arise even if
the use does not mount anything explicitly at "/".
Latest patch set causes the FileInfo of the empty top level emulated
directory to return "/" for Name() and Zero Time for ModTime() and
removes the related struct state fields being used in the previous
implementation.
Fixesgolang/go#14190
Change-Id: Idce2fc3c9b81206847a33840d76b660059d53d18
Reviewed-on: https://go-review.googlesource.com/19445
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
