Re: re-detect SCSi bus? Skript

Kurt Garloff (garloff@kg1.ping.de)
Thu, 19 Mar 1998 10:47:22 +0100

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Content-Type: text/plain; charset=us-ascii

On Wed, Mar 18, 1998 at 05:14:17PM -0600, shalon@interlock.dfw.ibm.com wrote:
> Hmm. I'm not *that* familiar with SCSI, but I would assume that that
> add-single-device would fail if there was no device attached, yes? How
> hard would it be to write a script that simply checked to see how many
> hosts you had, how many channels you had, and what devices were
> already know. Then it would simply run down the list of "Host Channel
> Id" skipping any which were already known. You also could give the
> script an Id to check all LUNs on.
>
> This is of course assuming that there are no bad side effects to
> trying to add a nonexistant SCSI device; I'll take a look when I get
> home tonight and have source.

I wrote a little skript. Have a look at it ...
It takes some options.

> On a similar note, is there a 'remove-single-device command'? How hard
> would it be to add?

There is. Exactly with the name you guessed. Linux is that easy sometimes.

-- 
Kurt Garloff, Dortmund 
<K.Garloff@ping.de>
PGP key on http://student.physik.uni-dortmund.de/homepages/garloff


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Content-Type: application/x-sh
Content-Disposition: attachment; filename="rescan-scsi-bus.sh"


#!/bin/bash
# Skript to rescan SCSI bus, using the 
# scsi add-single-device mechanism
# (w) 98/03/19 Kurt Garloff <K.Garloff@ping.de> (c) GNU GPL


# Return hosts. /proc/scsi/HOSTADAPTER/? must exist
findhosts ()
{
  hosts=
  for name in /proc/scsi/*/?; do
    name=${name#/proc/scsi/}
    if test ! $name = scsi
      then hosts="$hosts ${name#*/}"
      echo "Host adapter ${name#*/} (${name%/*}) found."
    fi
  done
}


# Test if SCSI device $host $channen $id $lun exists
# Outputs description from /proc/scsi/scsi, returns new
testexist ()
{
  grepstr="scsi$host Channel: 0$channel Id: 0*$id Lun: 0$lun"
  new=`cat /proc/scsi/scsi|grep -e"$grepstr"`
  if test ! -z "$new"
    then cat /proc/scsi/scsi|grep -e"$grepstr"
    cat /proc/scsi/scsi|grep -A2 -e"$grepstr"|tail -2|pr -o4 -l1
  fi
}


# Perform search (scan $host)
dosearch ()
{
  for channel in $channelsearch; do
    for id in $idsearch; do
      for lun in $lunsearch; do
        new=
	devnr="$host $channel $id $lun"
	echo "Scanning for device $devnr ..."
	printf "OLD: "
	testexist
	if test -z "$new"
	  then printf "\rNEW: "
	  echo "scsi add-single-device $devnr" >/proc/scsi/scsi
	  testexist
	  if test -z "$new"; then printf "\r\x1b[A"; else let found+=1; fi
	fi
      done
    done
  done
}
	  
  
# main
if test @$1 = @--help -o @$1 = @-h
  then 
    echo "Usage: rescan-scsi-bus.sh [-l] [-w] [-c] [host [host ...]]"
    echo " -l activates scanning for LUNs 0 .. 7 [default: 0]"
    echo " -w enables scanning for device IDs 0 .. 15 [def.: 0 .. 7]"
    echo " -c enables scanning of channels 0 1 [default: 0]"
    echo " If hosts are given, only these are scanned [def.: all]"
    exit 0
fi


# defaults
lunsearch="0"
idsearch="0 1 2 3 4 5 6 7"
channelsearch="0"


# Scan options
opt="$1"
while test ! -z "$opt" -a -z "${opt##-*}"; do
  opt=${opt#-}
  case "$opt" in
    l) lunsearch="0 1 2 3 4 5 6 7" ;;
    w) idsearch="0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15" ;;
    c) channelsearch="0 1" ;;
    *) echo "Unknown option -$opt !" ;;
  esac
  shift
  opt="$1"
done    


# Hosts given ?
if test @$1 = @; then findhosts; else hosts=$*; fi


declare -i found=0
for host in $hosts; do dosearch; done
echo "$found new device(s) found.               "


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