Patchset to add asynchronous open/close to master

[Jeremy Allison]

On Wed, Jun 20, 2012 at 06:42:10PM -0700, Jeremy Allison wrote:
> On Wed, Jun 20, 2012 at 05:42:13PM -0700, Jeremy Allison wrote:
> > 
> > What I'm planning is to write some test code that
> > checks if on modern glibc systems that setreuid()
> > only changes the euid/egid of the specific thread
> > it is called from, and if so we're already good
> > for the aio open code.
> > 
> > If (as appears possible now I've looked at the
> > glibc code) they have changed this to cause
> > setreuid() to do the SETXID signalling (which
> > is what glibc uses internally to request individual
> > threads change their own uid/gids) then we will
> > need to change source3/lib/util_sec.c to use
> > the raw system setreuid() system call directly
> > instead of going through the glibc wrapper, in
> > order to keep the same functionalty we are
> > already depending on in Linux.
> > 
> > I'll report back once I've tested things more.
> 
> Ok, attached is some test code (run as root :-).
> 
> Looks like glibc has changed setreuid to use
> the SETXID call.
> 
> Using setreuid:
> 
> # ./a.out 
> MAIN THREAD 1: uid = 0, gid = 0
> CHILD THREAD 1: uid = 0, gid = 0
> MAIN THREAD 2: uid = 300, gid = 300
> CHILD THREAD 2: uid = 300, gid = 300
> 
> Using syscall(SYS_setreuid,...)
> 
> # ./a.out 
> MAIN THREAD 1: uid = 0, gid = 0
> CHILD THREAD 1: uid = 0, gid = 0
> MAIN THREAD 2: uid = 300, gid = 300
> CHILD THREAD 2: uid = 0, gid = 0
> 
> So looks like we need to change to using
> syscall(SYS_setreuid,...) in Samba on Linux
> instead of calling setreuid() directly, as
> the current glibc breaks the assumptions
> of we're using inside the aio code.
> 
> I'll prepare a patch for master/3.6.x
> to fix this issue.

Forgot to add the test code :-)
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