All users of this mechanism have been switched to anonymous files and
passing file descriptors with sendfd()/recvfd().
Shbufs got us where we are today, but it's time we say good-bye to them
and welcome a much more idiomatic replacement. :^)
This 'data loss' was introduced in 809a8ee693, because
I hoped we could eventually outlaw overlong paths entirely. This sparked some discussion:
https://github.com/SerenityOS/serenity/discussions/4357
Among other things, we agree that yeah, the Kernel can and should be able to return
paths of arbitrary length. This means that the 'arbitrary' maximum of PATH_MAX in
UserspaceEmulator should be considered to be unnecessary data loss, and as such, needs to
be fixed.
This API was a mostly gratuitous deviation from POSIX that gave up some
portability in exchange for avoiding the occasional strlen().
I don't think that was actually achieving anything valuable, so let's
just chill out and have the same open() API as everyone else. :^)
