getpwent bug?

Jens Rehsack rehsack at
Fri Jul 16 16:22:44 UTC 2010

On 07/16/10 15:07, Dan Nelson wrote:
> In the last episode (Jul 16), Jens Rehsack said:
>> 2010/7/16 Dan Nelson<dnelson at>:
>>> In the last episode (Jul 16), Ashish SHUKLA said:
>>>> Well, OP is also invoking 'endpwent()' after every 'getpwent()'
>>>> invocation which according to GNU/Linux's glibc and NetBSD's libc (as
>>>> OP mentioned) should rewind the position in passwd database to the
>>>> beginning.
>>> Ah. I missed the endpwent calls.
>> Was difficult for me to format the single liner ;)
>>>> To me it definitely looks like a bug in FreeBSD's getpw*() family of
>>>> functions.
>>>> As tested using sysutils/lsof, in the following program in FreeBSD, the
>>>> descriptor corresponding to '/etc/pwd.db' is closed on endpwent(3) but
>>>> position in database is never rewinded as shown in the output.
>>> It looks like the *pwent functions keep an internal counter that
>>> endpwent doesn't reset.
>> Could you please take a look to my other mail (getgrent related) - there
>> seems another bug ...
> Do you have another one-liner that will reproduce it?  A simple
> "/usr/bin/getent group" doesn't return dupes for me.  Oddly enough, the
> *grent code doesn't use an internal counter, so the bug you found in
> endpwent doesn't exist in endgrent (afaik; the nsswitch code isn't that easy
> to read).

Not really a one-liner:
perl -MData::Dumper -e 'setgrent; my %dupchk; while( my ( $name, $grpass, 
$gid, $members ) = getgrent() ) { print "$name is returned more than once 
(No $dupchk{$name} comes here)\n" if( $dupchk{$name}++ ); print Dumper( [ 
$name, $grpass, $gid, $members ] ) };'

setgrent() doesn't work here.

Best regards,

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