[RFC]: switch to 2.6 linux emulation on default

[Alexander Leidinger]

Quoting Ed Schouten <ed at 80386.nl> (from Fri, 30 May 2008 07:04:53 +0200):

> Hello Roman,
>
> * Roman Divacky <rdivacky at freebsd.org> wrote:
>> FreeBSD 7.0 contains support for running emulation of Linux 2.6
>> (= NPTL, futexes, TLS basically) and I'd like to switch this
>> on default in HEAD to see if we can ship 8.0 with this emulation
>> running on default.
>
> Speaking about Linux emulation: a couple of days ago I added Linux
> support to my TTY code in the mpsafetty branch. This means that it can
> handle the things done in posix_openpt() and ptsname().
>
> Because Linux wants the minor number to be within a certain region, the
> PTY driver creates a linux_device_handler for each device. ptsname()

There's already something like a device handler or wrapper or whatever  
(I hadn't a close look at this) for some devices. Does your work use  
this existing infrastructure or is this something else?

> seems to do an fstat() on the controller descriptor, followed by looping
> on the files in /dev and /dev/pts, to find the matching device number.
>
> Unfortunately sendmsg() seems broken on amd64 with COMPAT_LINUX32. This

The LTP test (http://wiki.freebsd.org/linux-kernel/ltp) for sendmsg  
tells it is broken on all architectures. Did you test on a i386 system  
too?

> means that SSH'ing to a Linux jail only works on i386, or on amd64 when
> logging in as root (in that case sshd seems to be taking a shortcut, not
> causing sendmsg() to be called).

That's not nice, this should work even for normal users. I think we  
should raise the priority for the sendmsg part.

Bye,
Alexander.

-- 
Hawkeye's Conclusion:
	It's not easy to play the clown
	when you've got to run the whole circus.

http://www.Leidinger.net    Alexander @ Leidinger.net: PGP ID = B0063FE7
http://www.FreeBSD.org       netchild @ FreeBSD.org  : PGP ID = 72077137