X-Recipient: archive-cygwin AT delorie DOT com DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:message-id:date:from:mime-version:to:subject :references:in-reply-to:content-type:content-transfer-encoding; q=dns; s=default; b=dHt8d4J5gWcyL6d+UKLlnydfWFD/gQ70Roc03xjhbWG Tnt+3gxS0vM94LKVT+abY2eXL37fWGZsG2K3WyFGSOBC+gQRj5/EK82rq70kLt1Q mtyE+uVbBqbAPT5KLuo6Hg6r5NHPm/WdtwUiUAC8OPTq3sZIscp4E32N9WOOw3iI = DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:message-id:date:from:mime-version:to:subject :references:in-reply-to:content-type:content-transfer-encoding; s=default; bh=izZJ0lRepVzwcerQqbpF1DB7LPk=; b=gTy32k8ZNZQOOkgVI 5TTTwNqeRU2QMlf4+xx8USqpz0ZFUbOzjMo0qNvAMKWp8hUyzEUS7/haF7XWOZgs rB5+ym2JQ+mrc62TR8CMN4pvYlogToXdCttuDdJR+/SkjDYG1PHsGP34dZP6cvSG 9sfncQPScjzIo6p/ON2P2K8m3s= Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD,SPF_PASS autolearn=ham version=3.3.2 X-HELO: limerock04.mail.cornell.edu X-CornellRouted: This message has been Routed already. Message-ID: <52FB9E51.7030607@cornell.edu> Date: Wed, 12 Feb 2014 11:16:17 -0500 From: Ken Brown User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: cygwin AT cygwin DOT com Subject: Re: get rid of getpwent? (Was: cygwin-1.7.28 getpwent header declaration changes ?) References: <31347914-BB4F-4039-984B-731B6C72F903 AT etr-usa DOT com> <52F7AEC5 DOT 5090205 AT tiscali DOT co DOT uk> <8B7B5FE0-7413-4358-BA8A-E0B6E0B17653 AT etr-usa DOT com> <52F8B50E DOT 7040307 AT lysator DOT liu DOT se> <52F92D58 DOT 9030408 AT etr-usa DOT com> <52F95D1D DOT 4050108 AT tiscali DOT co DOT uk> <4510121021 DOT 20140211062515 AT mtu-net DOT ru> <52FAB14C DOT 8060800 AT tiscali DOT co DOT uk> <52FABAF5 DOT 2060701 AT etr-usa DOT com> <52FAD730 DOT 9090507 AT redhat DOT com> <20140212090804 DOT GM2821 AT calimero DOT vinschen DOT de> In-Reply-To: <20140212090804.GM2821@calimero.vinschen.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes On 2/12/2014 4:08 AM, Corinna Vinschen wrote: > On Feb 11 19:06, Eric Blake wrote: >> On 02/11/2014 05:06 PM, Warren Young wrote: >>> On 2/11/2014 16:25, David Stacey wrote: >>>> getpwent() is called in three different places. >>> >>> To those of you who have investigated these code paths: do any of them >>> look like they couldn't be replaced by getpwnam() or other calls that >>> would let cygwin1.dll do single-record AD/SAM lookups, rather than >>> whole-table/tree scans? >>> >>> That is, do any of these programs really need to visit every record in >>> /etc/passwd? >> >> libreadline wants to know how to tab-complete ~foo; to do that, it has >> to find all usernames beginning with foo. How would you do that without >> visiting every single record? > > This seems to be the major usage of getpwent these days. The question > is, how bad is it if only a handful entries, or even only a single one > (of oneself) show up? > > Either way, implementing a full getpwent requires to return the local > users, the users of the primary domain, and the users of all trusted > domains. I know of domains with 200K users and there are probably > bigger ones. How long should a search take when a user presses > after the ~? And then, shall the process running the getpwent actually > cache all of them? This seems really excessive. What about the following compromise: If /etc/passwd exists, then getpwent behaves as it does currently. Otherwise, it returns a handful of entries, or possibly just the current user. This gives users a choice. If tab-completion in this situation is important to them, they can keep their /etc/passwd file. Ken -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple