Re: Removal of compat-FreeBSD

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

Le 15/02/2015 20:34, David Holland a écrit :
> On Sun, Feb 15, 2015 at 04:31:36PM +0100, Maxime Villard wrote:
>   > The funny thing is that a simple, *valid* call to sched_getparam()
>   > crashes the system. Clearly, it means that in 6 years, nobody
>   > tested it. As I stated, we should normally have received a bug
>   > report from someone, but we didn't. It either means there's an
>   > insidious conspiracy against us, or, nobody uses it.
>
> sched_getparam() is hardly a main-line function. I could easily
> imagine running compat binaries for years and never happening to use
> one that calls it. So I think your reasoning is suspect.

Arguable perhaps, but not suspect. We all know that nasty bugs lie in 
unused/rarely used code, yet they are still there to play with if 
someone wants to. And there goes bad press. The big difference between 
this and a crappy ioctl is that the ioctl works only when the hardware 
behind is present.

>   > The problem is that these bugs affect the i386 users, most of which don't
>   > use compat_freebsd. This compatibility layer comes at the cost of security,
>   > and is - as I/you said - very incomplete.
>
> By this same reasoning we should not have any binary compat code at
> all. The only thing you've cited that's different about the freebsd
> compat code is that it's out of date -- the proper response to that is
> to update it. It's not like freebsd's syscall ABI is secret or
> anything.

I hardly see the point in updating such compat code, unless some new 
binary requires a more recent freebsd API/ABI. In that particular case 
better move to compat_linux (I hardly see who would provide a FreeBSD 
binary without a Linux one nowadays).

Or deprecate old code gradually by making it root-only first (at least 
for syscall related stuff) then squash it at a later time.

Cheers,

--
Jean-Yves Migeon