Re: [PATCH] io: Refactor close_range and closefrom

[Sergey Bugaev <bugaevc@gmail.com>]

On Mon, Nov 8, 2021 at 5:55 PM Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
> > Is this (either closes everything or nothing) an appropriate thing to
> > promise in the common header? Similarly, if the default implementation
> > accepts no flags, should the common description mention "the
> > CLOSE_RANGE prefix"?
>
> Well, that's the semantic of the both the syscall and the Linux fallback.
> If Hurd does not provide such semantic I think you should work this out.

My Hurd patch does provide that semantic. I'm concerned about this
being promised in the generic header; some other port/kernel could
potentially decide to instead stop & propagate an error from closing a
descriptor. Perhaps the claim could be qualified (for instance, "In
all current ports, ...")? Not that this matters.

Another suggestion:

> +  for (int i = 0; i < maxfd; i++)
> +    if (i >= lowfd)
> +      __close_nocancel_nostatus (i);

This should be

int i;
for (i = first; i <= last && i < maxfd; i++)
  __close_nocancel_nostatus (i);

shouldn't it?

How does that even compile? 'lowfd' is the name of closefrom's
argument. close_range's arguments are 'first' and 'last' (and
'flags').

Sergey