Wine on OpenBSD, Theo de Raadt

[Yann Droneaud-2]

Hi,

In a recent post ( <http://lwn.net/Articles/360312/> ), Theo de Raadt is
criticising Linux page 0 handling.
He argue that Linux allows page 0 mapping only for Wine.
And OpenBSD won't allow page 0 mapping for security reasons (and
performance reasons).

Since Wine seems to be working on other *BSD and derivative systems,
is this a problem ?

Could someone comment on this issue. I don't find anything related on
<http://wiki.winehq.org/OpenBSD>

Regards.

--
Yann Droneaud

[Marcus Meissner]

On Thu, Nov 05, 2009 at 02:21:47PM +0100, Yann Droneaud wrote:

> Hi,
>
> In a recent post ( <http://lwn.net/Articles/360312/> ), Theo de Raadt is
> criticising Linux page 0 handling.
> He argue that Linux allows page 0 mapping only for Wine.
> And OpenBSD won't allow page 0 mapping for security reasons (and
> performance reasons).
>
> Since Wine seems to be working on other *BSD and derivative systems,
> is this a problem ?
>
> Could someone comment on this issue. I don't find anything related on
> <http://wiki.winehq.org/OpenBSD>

Its actually not a real problem for Wine, last years code works without
NULL pages.


Our DOS emulator requires it, as vm86() mode uses 0 based mapping,
so DOS programs won't work afterwards. But otherwise I see no dependency.
(Perhaps Win16, but I dont think so.)

Ciao, Marcus

[Yann Droneaud-2]

Le jeudi 05 novembre 2009 à 17:01 +0100, Marcus Meissner a écrit :

> On Thu, Nov 05, 2009 at 02:21:47PM +0100, Yann Droneaud wrote:
> > Hi,
> >
> > In a recent post ( <http://lwn.net/Articles/360312/> ), Theo de Raadt is
> > criticising Linux page 0 handling.
> > He argue that Linux allows page 0 mapping only for Wine.
> > And OpenBSD won't allow page 0 mapping for security reasons (and
> > performance reasons).
> >
> > Since Wine seems to be working on other *BSD and derivative systems,
> > is this a problem ?
> >
> > Could someone comment on this issue. I don't find anything related on
> > <http://wiki.winehq.org/OpenBSD>
>
> Its actually not a real problem for Wine, last years code works without
> NULL pages.
>

It seems many people thinks Wine needs to mmap the page 0 to run common
application.

Does Wine 1.0 need it ?

If not, it's really a myth.

>
> Our DOS emulator requires it, as vm86() mode uses 0 based mapping,
> so DOS programs won't work afterwards. But otherwise I see no dependency.
> (Perhaps Win16, but I dont think so.)
>

According to this post from Alexandre Julliard, win16 don't need it.

http://old.nabble.com/Re%3A-vm86-mode-is-not-supported-p23884662.html

Perhaps it could be good point if there's a way to disable DOS emulator
at build time ?

Regards

--
Yann Droneaud

[Marcus Meissner]

On Thu, Nov 05, 2009 at 05:31:52PM +0100, Yann Droneaud wrote:

> Le jeudi 05 novembre 2009 à 17:01 +0100, Marcus Meissner a écrit :
> > On Thu, Nov 05, 2009 at 02:21:47PM +0100, Yann Droneaud wrote:
> > > Hi,
> > >
> > > In a recent post ( <http://lwn.net/Articles/360312/> ), Theo de Raadt is
> > > criticising Linux page 0 handling.
> > > He argue that Linux allows page 0 mapping only for Wine.
> > > And OpenBSD won't allow page 0 mapping for security reasons (and
> > > performance reasons).
> > >
> > > Since Wine seems to be working on other *BSD and derivative systems,
> > > is this a problem ?
> > >
> > > Could someone comment on this issue. I don't find anything related on
> > > <http://wiki.winehq.org/OpenBSD>
> >
> > Its actually not a real problem for Wine, last years code works without
> > NULL pages.
> >
>
> It seems many people thinks Wine needs to mmap the page 0 to run common
> application.
>
> Does Wine 1.0 need it ?
>
> If not, it's really a myth.

I installed 1.0.1 , enabled mmap_min_addr protectionm ...

Testcase:
Firefox 3.5.4 ... installs and runs nicely. (OK, I had
some crashes after Flash Player installation for youtube, but
youtube plays).

> According to this post from Alexandre Julliard, win16 don't need it.
>
> http://old.nabble.com/Re%3A-vm86-mode-is-not-supported-p23884662.html
>
> Perhaps it could be good point if there's a way to disable DOS emulator
o> at build time ?

You do not know that at build time. My WINE rpms build for i586 can be run on
i586 and x86_64 machines.

Ciao, Marcus

[Mihai Donțu]

On Thursday 05 November 2009 18:31:52 Yann Droneaud wrote:

> Le jeudi 05 novembre 2009 à 17:01 +0100, Marcus Meissner a écrit :
> > On Thu, Nov 05, 2009 at 02:21:47PM +0100, Yann Droneaud wrote:
> > > Hi,
> > >
> > > In a recent post ( <http://lwn.net/Articles/360312/> ), Theo de Raadt
> > > is criticising Linux page 0 handling.
> > > He argue that Linux allows page 0 mapping only for Wine.
> > > And OpenBSD won't allow page 0 mapping for security reasons (and
> > > performance reasons).
> > >
> > > Since Wine seems to be working on other *BSD and derivative systems,
> > > is this a problem ?
> > >
> > > Could someone comment on this issue. I don't find anything related on
> > > <http://wiki.winehq.org/OpenBSD>
> >
> > Its actually not a real problem for Wine, last years code works without
> > NULL pages.
>
> It seems many people thinks Wine needs to mmap the page 0 to run common
> application.
>
> Does Wine 1.0 need it ?
>
> If not, it's really a myth.
>

# sysctl vm.mmap_min_addr
vm.mmap_min_addr = 4096

and wine works like a charm.

> > Our DOS emulator requires it, as vm86() mode uses 0 based mapping,
> > so DOS programs won't work afterwards. But otherwise I see no dependency.
> > (Perhaps Win16, but I dont think so.)
>

I've never been able to run a dos program in Wine, but I've never asked myself
why because I always had an alternative.

> According to this post from Alexandre Julliard, win16 don't need it.
>
> http://old.nabble.com/Re%3A-vm86-mode-is-not-supported-p23884662.html
>
> Perhaps it could be good point if there's a way to disable DOS emulator
> at build time ?
>

--
Mihai Donțu

[David Gerard-2]

2009/11/5 Mihai Donțu <mihai.dontu@...>:

> I've never been able to run a dos program in Wine, but I've never asked myself
> why because I always had an alternative.


DOSbox is a much better DOS than Wine is ever likely to be.

Do Win32 console apps run okay in Wine without the page 0 mapping? I
ask because in my last job, we actually used Wine to run a Win32
console app on RHEL4 to save installing another Windows box. Never let
anyone tell you Wine isn't ready for the enterprise ;-)


- d.

[Mihai Donțu]

On Thursday 05 November 2009 19:44:47 David Gerard wrote:
> 2009/11/5 Mihai Donțu <mihai.dontu@...>:
> > I've never been able to run a dos program in Wine, but I've never asked
> > myself why because I always had an alternative.
>
> DOSbox is a much better DOS than Wine is ever likely to be.
>
> Do Win32 console apps run okay in Wine without the page 0 mapping? I
>

I use wine to run the Microsoft Visual Studio Express compiler (cl.exe). So
far I hadn't had any problems.

> ask because in my last job, we actually used Wine to run a Win32
> console app on RHEL4 to save installing another Windows box. Never let
> anyone tell you Wine isn't ready for the enterprise ;-)
>

--
Mihai Donțu

[David Laight]

On Thu, Nov 05, 2009 at 02:21:47PM +0100, Yann Droneaud wrote:
> And OpenBSD won't allow page 0 mapping for security reasons (and
> performance reasons).
>
> Since Wine seems to be working on other *BSD and derivative systems,
> is this a problem ?

NetBSD is likely to disable user space mapping of address 0 some time
in the near future - it does have problems with the compatibility code
for other unix system binariess though (I can't remember which ones,
compat-ultrix might be the one).

        David

--
David Laight: david@...