From: Ken Brown <kbrown@cornell.edu>
To: cygwin@cygwin.com
Subject: Re: get rid of getpwent? (Was: cygwin-1.7.28 getpwent header declaration changes ?)
Date: Wed, 12 Feb 2014 16:24:00 -0000 [thread overview]
Message-ID: <52FB9E51.7030607@cornell.edu> (raw)
In-Reply-To: <20140212090804.GM2821@calimero.vinschen.de>
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 <TAB>
> 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
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next prev parent reply other threads:[~2014-02-12 16:16 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-06 7:29 cygwin-1.7.28 getpwent header declaration changes ? Marco Atzeri
2014-02-06 9:01 ` Corinna Vinschen
2014-02-06 10:20 ` Marco Atzeri
2014-02-06 13:00 ` Jan Nijtmans
2014-02-06 14:02 ` Corinna Vinschen
[not found] ` <CAO1jNws3H_Wbec=y_UoYkhrb5nMX7iT7_A5XaHcQKCw32o055g@mail.gmail.com>
2014-02-06 14:15 ` Fwd: " Jan Nijtmans
2014-02-06 14:28 ` Corinna Vinschen
2014-02-06 14:41 ` Corinna Vinschen
2014-02-06 14:13 ` Corinna Vinschen
2014-02-06 21:43 ` get rid of getpwent? (Was: cygwin-1.7.28 getpwent header declaration changes ?) Warren Young
2014-02-07 9:49 ` Corinna Vinschen
2014-02-07 12:50 ` Andrey Repin
2014-02-07 17:26 ` Warren Young
2014-02-07 18:20 ` Andrey Repin
2014-02-07 13:53 ` David Stacey
2014-02-07 17:51 ` Warren Young
2014-02-07 19:21 ` Corinna Vinschen
2014-02-09 16:10 ` Warren Young
2014-02-09 16:16 ` Corinna Vinschen
2014-02-09 16:31 ` Corinna Vinschen
2014-02-09 16:37 ` Ken Brown
2014-02-09 17:12 ` David Stacey
2014-02-10 10:48 ` Warren Young
2014-02-10 13:16 ` Peter Rosin
2014-02-10 22:05 ` Warren Young
2014-02-10 23:35 ` David Stacey
2014-02-11 2:35 ` Andrey Repin
2014-02-12 0:06 ` David Stacey
2014-02-12 2:06 ` Warren Young
2014-02-12 3:54 ` Eric Blake
2014-02-12 9:09 ` Corinna Vinschen
2014-02-12 12:05 ` Andrey Repin
2014-02-12 15:16 ` Richard
2014-02-12 16:24 ` Ken Brown [this message]
2014-02-12 17:05 ` Richard
2014-02-12 17:15 ` Andrey Repin
2014-02-12 20:49 ` Corinna Vinschen
2014-02-12 22:53 ` Christopher Faylor
2014-02-13 11:46 ` Corinna Vinschen
2014-02-13 14:35 ` Andrey Repin
2014-02-13 14:38 ` Christopher Faylor
2014-02-13 15:37 ` Corinna Vinschen
2014-02-13 15:48 ` Christopher Faylor
2014-02-13 16:09 ` Corinna Vinschen
2014-02-13 18:33 ` get rid of getpwent? Achim Gratz
2014-02-13 19:02 ` Andrey Repin
2014-02-13 20:41 ` Corinna Vinschen
2014-02-13 21:48 ` Achim Gratz
2014-02-14 9:46 ` Corinna Vinschen
2014-02-12 4:40 ` get rid of getpwent? (Was: cygwin-1.7.28 getpwent header declaration changes ?) Andrey Repin
2014-02-07 20:09 ` Warren Young
2014-02-07 20:25 ` Warren Young
2014-02-07 21:01 ` Corinna Vinschen
2014-02-07 21:30 ` Corinna Vinschen
2014-02-07 21:49 ` Lavrentiev, Anton (NIH/NLM/NCBI) [C]
2014-02-08 10:38 ` Corinna Vinschen
2014-02-08 21:29 ` Lavrentiev, Anton (NIH/NLM/NCBI) [C]
2014-02-09 1:29 ` Lavrentiev, Anton (NIH/NLM/NCBI) [C]
2014-02-07 21:44 ` Larry Hall (Cygwin)
2014-02-07 22:45 ` David Stacey
2014-02-07 23:39 ` Larry Hall (Cygwin)
2014-02-08 0:50 ` Andrey Repin
2014-02-08 15:19 ` Warren Young
2014-02-08 15:39 ` Warren Young
2014-02-09 20:06 ` cygwin-1.7.28 getpwent header declaration changes ? Marco Atzeri
2014-02-09 20:20 ` Corinna Vinschen
2014-02-10 16:14 ` Marco Atzeri
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