#!/bin/sh
#
# Script to start a virtual rescudisk on a VServer

vrbase=/root
vrescuelog=/tmp/vcopy.log
vrdir=""

echo "TRACE: $0 $@" >> $vrescuelog

if [ "${1%%=*}" = "--cleanup" ]
then
  set -e
  vrdir=$vrbase/${1##*=}
  cd $vrdir/r
  umount proc
  umount target
  umount usr
  umount lib
  umount bin
  umount sbin

  rmdir proc
  rmdir target
  rmdir usr
  rmdir lib
  rmdir bin
  rmdir sbin
  rmdir dev/pts
  rm dev/*
  rmdir dev
  rm etc/*
  rmdir etc
  #rm *

  cd ..
  rmdir r
  cd ..
  rmdir $vrdir
  exit 0
fi

if [ "${1%%=*}" = "--build" ]
then
  vrdir=$vrbase/${1##*=}
  shift
  build="build"
else
  build=""
fi

if [ "${1%%=*}" = "--dir" ]
then
  vrdir=$vrbase/${1##*=}
  shift
  if ! cd $vrdir/r
  then
    echo "ERROR: Virtuall rescudisk '$vrdir' don't exist!"
    exit 110
  fi
fi

vserver=$1
shift

if [ "$vserver" = "--help" ] || [ "x$vserver" = "x" ]
then
  echo $"
USAGE: $0 [--dir=dir] vservername [[--running] command args*]
       $0 --build=dir vservername
       $0 --cleanup=dir
       $0 --help

Create a virutal rescudisk for vservername with the vserver root mounted
as /target. Run command in the rescudisk or start bash if no command are
given. When --dir is given use the prebuild rescudisk in dir.

When --running is given, run the kommand even if vserver is runing.

With --build a rescudisk is build in dir, that alows extra preparations
of the disc before commands are run. --cleanup try to remove the
rescudisk.

Don't trust the security of this rescuedisk, I'm a newbee on vserver!
"
  exit 0
fi

vconfdir="/etc/vservers"
vdir=$vconfdir/$vserver

if [ ! -d $vdir ]
then
  echo $vdir
  echo "VServer '$vserver' existerar inte!"
  exit 1
else
  if [ -f $vdir/context ]
  then
    context="--xid `cat $vdir/context`" # untested!
  else
    context=""
  fi
fi

if [ "x$vrdir" = "x" ]
then
  vrdir="rescue_$vserver$$"
  #echo $vrdir
  if ! $0 --build=$vrdir $vserver
  then
    exit $?
  fi
  $0 --dir=$vrdir $vserver "$@"
  err=$?
  $0 --cleanup=$vrdir
  exit $err
fi

if [ "$build" = "build" ]
then
  set -e
  mkdir $vrdir
  # Set chroot barrier
  mkdir $vrdir/r
  if ! cd $vrdir/r
  then
    echo Failed creating dir
    exit 1
  fi

  mkdir etc

  mkdir sbin
  mkdir bin
  mkdir lib
  mkdir usr
  mkdir target
  
  # NOTE on mount -r --bind!
  #
  # Mount --bind don't alowe shange in options, so ro don't work :-(
  #
  # Ther exist a kernel patch to fix this. Use them if You plan to run
  # anything untrusted in the rescue disk. OBS! Ther is probably allot
  # of other hole in the rescudisk, I'm a newbee on this!
  #
  # For now rw is good enuf.. rsync is the real use and kind of trust rsync

  mount -r --bind /sbin sbin
  mount -r --bind /bin bin
  mount -r --bind /lib lib
  mount -r --bind /usr usr
  mount --bind $vdir/vdir/. target

  mkdir proc
  mount --bind /proc proc
  # Proc hide?

  cp /etc/resolv.conf etc
  echo 127.0.0.1 localhost rescue-$vserver > etc/hosts
  echo "rescue-$vserver" > etc/hostname
  echo "root::0:0:root:/root:/bin/bash" > etc/passwd
  echo "nobody::65534:65534:nobody:/nonexistent:/bin/sh" >> etc/passwd
  echo "root::0:" > etc/group
  echo "nogroup::65534:" >> etc/group

  if [ -d /etc/vrescue.etc ]
  then
    cp -a /etc/vrescue.etc/* etc
  fi

  mkdir dev
  mkdir dev/pts
  cp -a /dev/random dev/
  cp -a /dev/urandom dev/
  cp -a /dev/null dev/
  cp -a /dev/log dev/
  cp -a /dev/fd dev/
  cp -a /dev/stderr dev/
  cp -a /dev/stdout dev/
  cp -a /dev/stdin dev/
  cp -a /dev/tty dev/
  cp -a /dev/zero dev/
  cp -a /dev/ptmx dev/
  # mkdir dev/loop/
  # cp -a /dev/loop/0 dev/loop/
  exit 0
fi

if [ "x$*" != "x" ]
then
  if vserver $vserver running
  then
    if [ "$1" = "--running" ]
    then
      shift
      context="--xid `cat $vdir/run`"
      echo "TRACE: vcontext --silent --migrate $context --chroot -- \"$@\"" >> $vrescuelog
      vcontext --silent --migrate $context --chroot -- "$@"
    else
      echo "ERROR: Vserver is running!"
      exit 100
    fi
  else
    if [ "$1" = "--running" ]
    then
      shift
    fi
    echo "TRACE: vcontext --silent --create $context --chroot -- \"$@\"" >> $vrescuelog
    vcontext --silent --create $context --chroot -- "$@"
  fi
else
  if vserver $vserver running
  then
    echo "OBS! VServer '$vserver' mounted as /target is running!"
    context="--xid `cat $vdir/run`"
    vcontext --migrate $context --chroot -- bash
  else
    echo "VServer '$vserver' mounted as /target is not running!"
    vcontext --create $context --chroot -- bash
  fi
fi