#!/usr/bin/perl -w

######################################################################
###
###   IMPORTANT!
###   Please read the warranty and legal notice 
###   at the end of this file!
###
######################################################################

require 5.000;
use lib '/usr/local/bin',"$ENV{HOME}/bin",'/usr/stud/loescher/bin';
use lib 'd:/bin','c:/mydos','c:/bin';
use slutil;
use English;

######################################################################
### Voreinstellungen
######################################################################

$version = '0.2 beta';
$appname = 'CreateDeviceLink';

$scsilist = 'scsilist';

######################################################################
### Hauptprogramm
######################################################################

&Hilfe if ($#ARGV<7);

printumlaute Kopf();

($device,$link,$oldperm,$oldown,$oldgrp,
               $newperm,$newown,$newgrp) = @ARGV;

$oldperm = oct $oldperm;
$newperm = oct $newperm;
$oldown = (getpwnam($oldown))[2];
$newown = (getpwnam($newown))[2];
$oldgrp = (getgrnam($oldgrp))[2];
$newgrp = (getgrnam($newgrp))[2];

die "Kein '$scsilist' gefunden!\n" unless which("$scsilist");

open(LIST, "$scsilist|");
@list = <LIST>;
chomp(@list);
close LIST;

select STDOUT; $|=1;

for ($i=0; $i<$#list-3; $i++)
{
  next unless $list[$i] =~ /\/dev\/sg/;
  if ($list[$i+2] =~ /$device/)
  {
    $dev = $list[$i];
    $dev =~ s/.+?(\/dev\/sg.).*/$1/;
    print "Gerät '$device' ist '$dev'\n";

    if (-e "/dev/$link") # Existiert schon ein Link/File?
    {
      if (!-l "/dev/$link") # Ist es ein Link?
      {
	print "'/dev/$link' ist KEIN Symlink! Abbruch!\n";
	exit;
      }
      else
      {
	$oldlink = readlink "/dev/$link";
	print "Alter Link: $oldlink\n";
	print "chown $oldown, $oldgrp, $oldlink\n";
	chown ($oldown, $oldgrp, $oldlink) || die "Fehler!!!\n";
	print "chmod $oldperm, $oldlink\n";
	chmod ($oldperm, $oldlink) || die "Fehler!!!\n";
	print "unlink /dev/$link\nErgebnis:\n";
	unlink ("/dev/$link") || die "Fehler!!!\n";
	system("/bin/ls -l $oldlink");
	print "\n";
      }
    }
    print "symlink $dev, /dev/$link\n";
    symlink ($dev, "/dev/$link") || die "Fehler!!!\n";
    print "chown $newown, $newgrp, $dev\n";
    chown ($newown, $newgrp, $dev) || die "Fehler!!!\n";
    print "chmod $newperm, $dev\nErgebnis:\n";
    chmod ($newperm, $dev) || die "Fehler!!!\n";
    system("/bin/ls -l $dev");
    system("/bin/ls -l /dev/$link");

    exit;
  }
}

printumlaute "Gerät '$device' ist nicht vorhanden!\n";

######################################################################
### Unterprogramme
######################################################################

sub Kopf
{
  my $head = "$appname $version   -   von Stephan Löscher";
  return "\n$head\n" . '~' x length($head) . "\n";
}


sub Hilfe
{
  printumlautepaged
  Kopf().
"Syntax: createdevicelink Gerät Link oldperm oldown oldgrp newperm newown newgrp

Erstellt symbolische Links für Geräte in /dev und ändert dabei auch die
Dateirechte und Besitzer. Das ist für alle nützlich, die SCSI-Geräte öfters
aus- oder einschalten und sich dann wundern, wenn die /dev/sgX nicht mehr
stimmen.

Beispiel: createdevicelink C2500A scanner 600 root root 660 root scanner

Es wird dann in /dev/ ein Link von /dev/scanner auf das SCSI-generic-device,
das dem Gerät entspricht erzeugt, also z.B.:
scanner -> /dev/sgf
Dabei erhält das Device, auf das der Link vorher zeigte die Rechte 600 und
das Device, hinter dem sich der C2500A verbirgt die Rechte 660.
(Owner/Gruppen analog.)

";
exit;
}


######################################################################
#
# Warranty and legal notice
# ~~~~~~~~~~~~~~~~~~~~~~~~~
#
# Copyright (c) 1997 by Stephan Löscher  -  all rights reserved
# My Address: Stephan Löscher, Dr.Troll-str. 3, 82194 Gröbenzell, Germany
# Email: loescher@gmx.de
# WWW: http://www.loescher-online.de/
#
# This program is freeware.
# It is NOT Public-Domain-Software!
# The author (Stephan Löscher) does NOT give up his copyright, but he 
# reserves his copyright. Usage and copying is free of charge for private
# use, but NOT for commercial use!
# 
# You may and should copy this program free of charge, use it,
# give it to your friends, upload it to a BBS or something similar, under
# the following conditions:
# * Don't charge any money for it. If you upload it to a BBS, make sure that
#    it can be downloaded free (without paying for downloading it, except
#    for usage fees that have to be paid anyway). Small copying fees (up to
#    5 DM or 3 $US) may be charged.
#  * Only distribute the whole original package, with all the files included.
#  * This program may not be part of any commercial product or service without
#    the written permission by the author.
#  * If you want to include this program on a CD-ROM and/or book, please send
#    me a free copy of the CD/book (this is not a must, but I would appreciate
#    it very much).
# 
# Distribution of the program is explicitly desired, provided that the above
# conditions are accepted.
# 
# YOU ARE USING THIS PROGRAM AT YOUR OWN RISK! THE AUTHOR (STEPHAN LÖSCHER)
# IS NOT LIABLE FOR ANY DAMAGE OR DATA-LOSS CAUSED BY THE USE OF THIS PROGRAM
# OR BY THE INABILITY TO USE THIS PROGRAM. IF YOU ARE NOT SURE ABOUT THIS, OR
# IF YOU DON'T ACCEPT THIS, THEN DO NOT USE THIS PROGRAM!
# BECAUSE OF THE VARIOUS HARDWARE AND SOFTWARE ENVIRONMENTS INTO WHICH THIS
# PROGRAM MAY BE PUT, NO WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE IS
# OFFERED.
# GOOD DATA PROCESSING PROCEDURE DICTATES THAT ANY PROGRAM BE THOROUGHLY
# TESTED WITH NON-CRITICAL DATA BEFORE RELYING ON IT.
# 
# No part of the documentation may be reproduced, transmitted, transcribed,
# stored in any retrieval system, or translated into any other language in
# whole or in part, in any form or by any means, whether it be electronic,
# mechanical, magnetic, optical, manual or otherwise, without prior written
# consent of the author, Stephan Löscher.
# 
# You may not make any changes or modifications to this software or this
# manual. You may not decompile, disassemble, or otherwise reverse-engineer
# the software in any way.
# If you got the source, then you are permitted to modify it if you
# contact me and tell me your enhancements.
# You also may include the source as a whole or parts of it into other
# programs, as long as you don't make profit directly out of selling
# the result. If you re-use code of this program then do not remove my name!
# If you include this source-code in your projects, mark it clearly as such
# "... derived from code XXX by Stephan Löscher".
# But don't distribute modified code!
# 
# If you believe your copy of this software has been tampered or altered in
# anyway, shape or form, please contact me immediately! Do not hesitate a
# moment to inform me. Remember, this software should be available to all, in
# the original form, so please do not accept modified or damaged versions of
# my software.
# 
# The author reserves his right for taking legal steps if the copyright or the
# license agreement is violated.
# 
# All product names mentioned in this software are trademarks or registered
# trademarks of their respective owners.
# 
# If you have any questions, ideas, suggestions for improvements or if you find
# bugs (I don't hope so.) then feel free to contact me. (Email is appreciated.)
# 
# I'm not a native english speaker. If you are one and discover some strange
# sounding parts in this documentation or in the program, please, feel free
# to point it out to me and give me suggestions for alteration!
# 
# If the program works for you, and you want to honour my efforts, you are
# invited to donate as much as you want... :)
#
# In any case, if you don't like the restrictions in this license, contact
# me, and we can work something out.
#
######################################################################