Date: Tue, 13 Nov 2012 16:04:33 -0700 From: Warner Losh <imp@bsdimp.com> To: Baptiste Daroussin <bapt@freebsd.org> Cc: Konstantin Belousov <kostikbel@gmail.com>, arch@freebsd.org Subject: Re: Increasing MAXLOGNAME from 17 to 33 Message-ID: <75177878-EA36-4472-BAEA-984A59F91057@bsdimp.com> In-Reply-To: <20121113225905.GB75103@ithaqua.etoilebsd.net> References: <20121113111806.GE62533@ithaqua.etoilebsd.net> <20121113115034.GJ73505@kib.kiev.ua> <20121113183412.GA75103@ithaqua.etoilebsd.net> <20121113184238.GO73505@kib.kiev.ua> <20121113184512.GP73505@kib.kiev.ua> <20121113225905.GB75103@ithaqua.etoilebsd.net>
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On Nov 13, 2012, at 3:59 PM, Baptiste Daroussin wrote: > 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 Isn't that check too late? Warner
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