#!/bin/sh
# /serve/sgi/sbin/switchconf - switch beteeen multiple sets of config files
# author Neil Franklin, last modification 2000.02.29

# to install:
#   create /home/<hostname>/system
#     copy scripts and share into here
#   create /home/<hostname>/homes1
#     in homes1 links to system

# presently installed on: truffaut

# these files have variable configs
FILES="/etc/hosts /etc/config/ifconfig-1.options /etc/config/static-route.options /etc/config/yp /homes1 /serve"

# on installing convert existing state tot his config
INSTOLDCONFIG=standard

# new configs should resemble this config
BASEADDCONFIG=$INSTOLDCONFIG

NAME=`echo $0 | tr "/" "\n" | tail -1`

# give users who do not know the game some help
if [ $# -gt 0 ] ; then
  if [ $1 = -help ] ; then
    echo "${NAME}: usage:"
    echo "  install on a computer: $NAME -install"
    echo "  uninstall from a computer: $NAME -uninstall"
    echo "  add annother config: $NAME -add <configname>"
    echo "  delete an existing config: $NAME -delete <configname>"
    echo "  tell what files are switched: $NAME -files"
    echo "  switch to a config: $NAME <configname> (or just simply <configname>)"
    echo "available <configname>s on this computer are:"
    ls -al /usr/local/sbin | grep " -> .*$NAME" | awk '{ print "  " $9 }'
    exit 0
  fi
fi

# special modes, for administering configs
if [ $# -gt 0 ] ; then
  case $1 in
    ( '-install' )
      if [ $# -gt 1 ] ; then
        echo "${NAME}: -install: too many parameters, try $NAME -help"
        exit 1
      fi
      # if there exists a INSTOLDCONFIG config for the first file, do not (re-)install
      if [ -f `echo $FILES | cut -f 1 -d ' '`.$INSTOLDCONFIG ] ; then
        echo ${NAME}: -install: we seem to have already installed here, aborting
        exit 1
      fi
      echo ${NAME}: setting up pseudo-server on /home/`hostname`
      mkdir /home/`hostname`/sgi /home/`hostname`/sgi/sbin
      cp -p /serve/sgi/sbin/switchconf /home/`hostname`/sgi/sbin
      mkdir /home/`hostname`/system /home/`hostname`/homes1
      cp -R /homes1/system/scripts /home/`hostname`/system
      cp -R /homes1/system/share /home/`hostname`/system
      ln -s /home/`hostname`/system /home/`hostname`/homes1
      echo ${NAME}: setting up first config
      # save existing config as the normal one, with name from INSTOLDCONFIG
      for FILE in $FILES ; do
        mv $FILE ${FILE}.$INSTOLDCONFIG
        ln -s ${FILE}.$INSTOLDCONFIG $FILE
      done
      ln -s $0 /usr/local/sbin/$INSTOLDCONFIG
      exit 0
    ;;
    ( '-uninstall' )
      if [ $# -gt 1 ] ; then
        echo "${NAME}: too many parameters, try $NAME -help"
        exit 1
      fi
      # if there does not exist a INSTOLDCONFIG config for the first file, do not (re-)uninstall
      if [ ! -f `echo $FILES | cut -f 1 -d ' '`.$INSTOLDCONFIG ] ; then
        echo ${NAME}: -uninstall: we seem to not be installed here, aborting
        exit 1
      fi
      rm -f /usr/local/sbin/$INSTOLDCONFIG
      # restoring INSTOLDCONFIG config als only state
      echo ${NAME}: unsetting first config
      for FILE in $FILES ; do
        rm $FILE
        mv ${FILE}.$INSTOLDCONFIG $FILE
      done
      echo ${NAME}: deleting pseudo-server on /home/`hostname`
      \rm -rf /home/`hostname`/system /home/`hostname`/homes1 /home/`hostname`/sgi
      exit 0
    ;;
    ( '-add' )
      if [ $# = 2 ] ; then
        ADDCONFIG=$2
        for FILE in $FILES ; do
          # symlinks can not be copied verbatim, dammit
          if [ -h ${FILE}.$BASEADDCONFIG ] ; then
            ln -s `ls -l ${FILE}.$BASEADDCONFIG | awk '{ print "  " $11 }'` ${FILE}.$ADDCONFIG
          else
            cp -p ${FILE}.$BASEADDCONFIG ${FILE}.$ADDCONFIG
          fi 
        done
        ln -s $0 /usr/local/sbin/$ADDCONFIG
        echo ${NAME}: added config: $ADDCONFIG
        exit 0
      else
        echo ${NAME}: -add requres a configname, try $NAME -help
        exit 1
      fi
    ;;
    ( '-delete' )
      if [ $# = 2 ] ; then
        DELCONFIG=$2
        for FILE in $FILES ; do
          rm ${FILE}.$DELCONFIG
        done
        rm -f /usr/local/sbin/$DELCONFIG
        echo ${NAME}: deleted config: $DELCONFIG
        exit 0
      else
        echo  ${NAME}: -delete requres a configname, try $NAME -help
        exit 1
      fi
    ;;
    ( '-files' )
      for FILE in $FILES ; do
        echo $FILE
      done
      exit 0
    ;;
    ( '-'* )
      echo ${NAME}: unknown command: $*, try $NAME -help
      exit 1
    ;;
  esac
fi

# determine what config the user wants
if [ $# -gt 1 ] ; then
  echo "${NAME}: too many parameters, try $NAME -help"
  exit 1
elif [ $# = 1 ] ; then
  CONFIG=$1
else
  # program can be linked to name of desired config
  CONFIG=$NAME
fi

# if there is not a config for the ffirst file, invalid config name, user error
if [ ! -f `echo $FILES | cut -f 1 -d ' '`.$CONFIG ] ; then
  echo "${NAME}: unknown <configname>, available <configname>s on this computer are":
  ls -al /usr/local/sbin | grep " -> .*$NAME" | awk '{ print "  " $9 }'
  exit >1
fi

# do the actual job
for FILE in $FILES ; do
  rm -rf $FILE
  ln -s ${FILE}.$CONFIG $FILE
done

echo ${NAME}: switched to config: $CONFIG