code review 5246052: syscall: add support for unshare(2) under linux

syscall: add support for unshare(2) under linux

Fixes issue 1954.

Credit for the original patch goes to jdnurmi@qwe.cc.

[dave_cheney.net, 2011-10-12 08:59:39]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://go.googlecode.com/hg/

[borman, 2011-10-12 17:32:00]

On 2011/10/12 08:59:39, dfc wrote:
> Hello mailto:golang-dev@googlegroups.com,
> 
> I'd like you to review this change to
> https://go.googlecode.com/hg/

I like having unshare support added.  I am not fond of duplicating over 200
lines and increasing the possibility of having linux and unix potentially have
conflicts.  I understand the no new stack segments issue.  I would be half
tempted to define SYS_UNSHARE as -1 on non-linux boxes and simply return an
EOPNOTSUP if sys.Unshare is set andand SYS_UNSHARE is -1.  The bits for
sys.Unshare should only be defined for linux so code using sys.Unshare would
still not compile.

[rsc, 2011-10-12 17:49:36]

I can't tell what changed.  Please make a backup copy
of the new files, hg remove them, and then do
hg cp exec_unix.go exec_bsd.go (and similarly exec_linux.go)
and copy them back.  Then hg upload and it will show
the diffs against exec_unix.go.

That said, I am pretty unhappy about having to duplicate
this code.  It is super subtle.  What are the changes?

Finally, if there is more than a line or two here
from jdnurmi@qwe.cc we need a completed CLA from him/her.
Sorry about that.

Russ

[dave_cheney.net, 2011-10-13 09:06:40]

*** Abandoned ***