2016-11-30 16:40 GMT+01:00 <cinap_lenrek@felloff.net>:

this makes no sense to me. the whole point of create with OEXCL is that
it is atomic and it will *NOT* try to truncate-open the file when it already
exist. OEXCL means just sending the Tcreate and nothing else. why is that not
already what you try todo with your new create syscall?

can you please state the problem that you are trying to fix?

Well, describing the whole picture would take a while (and would move the thread topic to other unusual aspects of its design), but one of the reason that can explain my question is that I want to simplify the kernel code as much as possible, moving to user space all that can be moved without affecting the system security.

In the end I'd like to get few orthogonal syscalls, so that you cannot obtain the exact effect of one in term of 2 or more other.

I know that this seem a bit theoretical, but it's just a starting point and has a lot of really pragmatic implications in my research project.

Stated in a different way, I want to keep it simple, and user space code is usually simpler than kernel space code.

Btw, actually, I'm not proposing a change to Plan 9 or debating about its design.
I'm just asking about the reasoning behind this specific choice, because I guess that it's deeper than it seem (so much that I cannot grasp it by reading the code).

Also I'm looking for "instances that *want* the existing effect", as Charles perfectly described them, something that break without it, so that I can dive deeper into the matter.

Giacomo