hotshot has asked for the wisdom of the Perl Monks concerning the following question:

Hi Guys

Is there a way to tell the getpwxxx functions to search only in the local /etc/passwd ?
If no such thing is possible, is there a way to do it without searching this file by myself?

Thanks

Hotshot

Replies are listed 'Best First'.
Re: getpwXXX
by virtualsue (Vicar) on Feb 20, 2002 at 13:46 UTC
    If you want to be certain that your script only searches a local /etc/passwd file, you'll have to do it yourself. On the bright side, it's not hard to do that: 
    open FH, '/etc/passwd' or die "Can't open /etc/passwd, $!";
my @matches = grep { chomp; /thing_to_match/ } <FH>;

    [download]
    or you can iterate through the file & split out each line like so: 
    while (<FH>) {
   chomp;
   my ($name, $passwd, $uid, $gid, $quota, $comment,
       $gcos, $dir, $shell) = split /:/;
}

    [download]
    The following code mimics getpwnam: 
    sub my_getpwnam {
   my $name_m = shift;
   open FH, '/etc/passwd' or die "Can't open /etc/passwd, $!";
   
   my @match = grep { chomp; /^$name_m:/ } <FH>;
   if (!@match) { return (); }  # return empty list if not found
   return split /:/, $match[0];
}

    [download]
    If you really don't want to do it yourself, tilly's Text::xSV module could be your answer.

    Update: Added a missing brace & stuck in an error check

[reply]
[d/l]
[select]
Re: getpwXXX
by derby (Abbot) on Feb 20, 2002 at 14:32 UTC
    hotshot,

    or have some fun with the c function fgetpwent and INLINE 

    #!/usr/local/bin/perl -w

use Inline C;
use Data::Dumper;

@ARGV || die "usage $0 <filename>\n";

$entries = getmypwent($ARGV[0]);

print Dumper( $entries );

__END__
__C__
#include <pwd.h>
#include <stdio.h>
#include <sys/types.h>

SV *getmypwent( char *filename )
{
   FILE *ih;
   struct passwd *p;
   int len;
   AV *array;
   HV *hash = newHV();

   if( ( ih = fopen( filename, "r" ) ) != NULL ) {
      while( p = fgetpwent( ih ) ) {
         hv_store(hash, p->pw_name, strlen(p->pw_name),
                        newRV_noinc((SV*)array = newAV()), 0);
         av_push(array, newSVpvf("%s", p->pw_passwd));
         av_push(array, newSVpvf("%d", p->pw_uid));
         av_push(array, newSVpvf("%d", p->pw_gid));
         av_push(array, newSVpvf("%s", p->pw_gecos));
         av_push(array, newSVpvf("%s", p->pw_dir));
         av_push(array, newSVpvf("%s", p->pw_shell));
      }
      fclose(ih);
   }

   return newRV_noinc((SV*) hash);
}

    [download]

    -derby

[reply]
[d/l]
Re: getpwXXX
by gellyfish (Monsignor) on Feb 20, 2002 at 13:10 UTC

    This is as system configuration rather than a Perl question - you will need to change the appropriate entry in /etc/nsswitch.conf (or whatever its equivalent is on your machine) so that it only looks in the files rather than going to NIS or whatever

    /J\

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[d/l]
Re: getpwXXX
by traveler (Parson) on Feb 20, 2002 at 16:30 UTC
    Check CPAN. There are modules to do that.

    HTH, --traveler

[reply]

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