Increasing MAXLOGNAME from 17 to 33

[Baptiste Daroussin]

On Tue, Nov 13, 2012 at 08:45:12PM +0200, Konstantin Belousov wrote:
> On Tue, Nov 13, 2012 at 08:42:38PM +0200, Konstantin Belousov wrote:
> > On Tue, Nov 13, 2012 at 07:34:12PM +0100, Baptiste Daroussin wrote:
> > > On Tue, Nov 13, 2012 at 01:50:34PM +0200, Konstantin Belousov wrote:
> > > > On Tue, Nov 13, 2012 at 12:18:06PM +0100, Baptiste Daroussin wrote:
> > > > > Hi,
> > > > > 
> > > > > I want to increase MAXLOGNAME in sys/param.h from 17 to 33 to allow 32-character
> > > > > long usernames, the PR: misc/161091 and misc/133926 already requested for it.
> > > > > 
> > > > > utmpx already allow 32 character long user names.
> > > > > 
> > > > > I plan to bump the __FreeBSD_version at the same time because of the ABI
> > > > > breakage.
> > > > > 
> > > > > This is simplify life of lots administrator, this value, is a common value for
> > > > > other operating systems.
> > > > > 
> > > > > Do anyone have objections about it?
> > > > 
> > > > Yes, I have. Do not break the ABI, it is plain prohibited.
> > > > You might consider increasing the constant only if providing ABI
> > > > compatibility shims.
> > > > 
> > > > In fact, the cursory look over the whole base system indicates that ABI
> > > > breakage might be not that big and could be mitigated with relatively
> > > > limited amount of the efforts.
> > > 
> > > Thanks cognet for the help on the following.
> > > 
> > > After auditing base, it seems like this patch is enough
> > > http://people.freebsd.org/~bapt/maxlogname-33.diff
> > Regarding the patch, the dereferencing of p->p_session should be done
> > under the proc lock to guarantee stability of p_pgrp, and under session
> > mutex to prevent s_login modifications. Altogether, this means that the
> > if() shall be moved down right before bcopy and locks unlocked on return.
> > 
> Sorry, sent the reply too early.
> 
> The alternative is to check for the length of the local 'login' variable
> after unlocks, right before copyout.
> 
like this?
http://people.freebsd.org/~bapt/report-erange-if-login-is-larger-then-MAXLOGNAME.diff

regards,
Bapt
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