[RFC][PATCH] Add envvar IO_BUFMODE to forcibly set buffering mode

[Luis Javier Merino]

Does this solve anything that isn't better dealt with by using
unbuffer from expect or stdbuf from coreutils?

On Thu, Mar 23, 2017 at 2:01 AM, Sunyeop Lee <sunyeop97@gmail.com> wrote:
> ---------- Forwarded message ----------
> From: Joseph Myers <joseph@codesourcery.com>
> Date: 2017-03-23 3:11 GMT+09:00
> Subject: Re: [RFC][PATCH] Add envvar IO_BUFMODE to forcibly set buffering mode
> To: Sunyeop Lee <sunyeop97@gmail.com>
>
>
> On Wed, 22 Mar 2017, Sunyeop Lee wrote:
>
>> Thanks for comment. I'll write a documentation and tests. I understand it
>> breaks standard semantics, but does it need to be disabled for setuid
>> programs even if it's secure? Anyone already can force "line buffering
>> mode" using pty even on setuid programs. I'm asking if it's possible to
>> allow only forced "line buffering mode" for setuid programs instead of
>> disabling it.
>
> Consider the case of a setuid program accessing a file rather than stdin /
> stdout / stderr, or invoking a non-setuid helper that does so or with
> input / output redirected.  It's only stdin/stdout/stderr that the caller
> of a setuid program can make point to either a pty or file at their
> choice.
>
> --
> Joseph S. Myers
> joseph@codesourcery.com