#!/bin/sh
# A script to restore /bin/busybox and delete the symlinks made during 
# installation.
#
# Symbolic links to applets are only removed if they are
# 1) created by the installer script ("install-binary.sh")
# 2) not replaced by a binary (i.e. they are still a symbolic link)
# 3) pointing to a busybox binary
#
# By Dennis Groenen <tj.groenen@gmail.com>
# GPLv3 licensed
#

INSTALLDIR="/opt/busybox-power"
EXECPWR="$INSTALLDIR/busybox.power"
DISTBIN="$INSTALLDIR/busybox.distrib"

VERBOSE="0"
MODIFIEDBIN="0"

INSTBINARY_SHA1=`sha1sum $EXECPWR | awk '{ print $1 }'`
if test -e $DISTBIN; then
  ORIGBINARY_SHA1=`sha1sum $DISTBIN | awk '{ print $1 }'`; fi

# Load shared functions
source $INSTALLDIR/functions

# Check whether we can load the list of created symlinks during installation
CHECK_SYMLINKSFILE() {
    if test ! -e $INSTALLDIR/busybox-power.symlinks; then
      echo -e "Warning: cannot find the list of symlinks to be removed. No" \
        "symlinks will be removed at all!\n" >> /tmp/busybox-power-error
    fi
}

# Check the (integrity) of our BusyBox backup
CHECK_BACKUP() {
    # Firstly, check whether the backup still exists
    if test ! -e $DISTBIN; then
      if test "$ENVIRONMENT" == "SDK"; then return; fi # SDK comes without BB
      echo -e "Warning: the backup of the original BusyBox binary is missing!" \
        "/bin/busybox will not be touched.\n" >> /tmp/busybox-power-error
      return
    fi

    # Secondly, check the integrity of the backup
    if test -e $INSTALLDIR/busybox.distrib.sha1; then
      if test "`cat $INSTALLDIR/busybox.distrib.sha1`" != "$ORIGBINARY_SHA1"; then
        if test -e $INSTALLDIR/busybox.distrib.version; then
          if test "`cat $INSTALLDIR/busybox.distrib.version`" == "`GETBBVERSION`"; then
            # The backup has been changed whilst busybox hasn't been upgraded
            echo -e "Warning: the backup of the original BusyBox binary has" \
              "been modified since installing busybox-power. Do not continue" \
              "unless you're sure that $DISTBIN is not corrupted.\n" \
              >> /tmp/busybox-power-error
          fi
        else
          echo -e "Warning: the backup of the original BusyBox binary has" \
          "been modified since installing busybox-power. We could not" \
          "determine whether this is due to a BusyBox upgrade (e.g. by an" \
          "(C)SSU update) or not. Do not continue unless either the latter is" \
          "the case, or you're via other ways sure that $DISTBIN is not" \
          "corrupted.\n" >> /tmp/busybox-power-error
        fi
      fi
    else
      echo -e "Warning: could not load the saved SHA1 checksum of the backup" \
        "of the original BusyBox binary; the integrity of the backup of the" \
        "original binary can not be guaranteed.\n" >> /tmp/busybox-power-error
    fi
}

# Check whether /bin/busybox has been modified after bb-power's installation
# This always happens on Harmattan when it receives a BusyBox upgrade;
# dpkg-divert is disallowed on that platform
CHECK_INSTALLEDBIN() {
    if test "$INSTBINARY_SHA1" != "`sha1sum /bin/busybox | awk '{ print $1 }'`"; then
      MODIFIEDBIN="1"

      if test "$ENVIRONMENT" == "HARMATTAN"; then
        if test -e $INSTALLDIR/busybox.distrib.version; then
          if test "`cat $INSTALLDIR/busybox.distrib.version`" != "`GETBBVERSION`"; then
            # Harmattan received a BusyBox upgrade, do not disturb the user by
            # warning that /bin/busybox has been modified
            return
          fi
        fi
        echo -e "Warning: /bin/busybox does not match busybox-power's binary" \
          "This can be the result of a BusyBox upgrade (e.g. by a MeeGo" \
          "update), an unsuccessful busybox-power installation, or a manual" \
          "replacement of it. Your current /bin/busybox won't be touched. Our" \
          "backup of the original BusyBox binary will be left at $DISTBIN.\n" \
          >> /tmp/busybox-power-error
      else
        echo -e "Warning: /bin/busybox does not match busybox-power's binary." \
          "Your current /bin/busybox won't be touched and the diversion of" \
          "/bin/busybox to $DISTBIN will not be removed.\n" \
          >> /tmp/busybox-power-error
      fi
    fi
}

# Display encountered errors
DISPLAY_ERRORS() {
    case $ENVIRONMENT in
      SDK)
        echo -e "\n\n-----------Attention!-----------"
        cat /tmp/busybox-power-error
        rm /tmp/busybox-power-error
        echo "-> Please press [enter] to ignore the above errors/warnings."
        echo "   Hit [ctrl-c] to break"
        read 
        ;;
      DIABLO|FREMANTLE)
        echo "Click \"I Agree\" to ignore the above errors/warnings. Ask for" \
          "help if you don't know what to do." >> /tmp/busybox-power-error
        echo "Please confirm the text on the screen of your device"
        maemo-confirm-text "Attention!" /tmp/busybox-power-error
        res=$?
        rm /tmp/busybox-power-error
        if test ! $res == 0; then exit 1; fi
        ;;
      HARMATTAN)
        echo "Click \"I Agree\" to ignore the above errors/warnings. Ask for" \
          "help if you don't know what to do." >> /tmp/busybox-power-error
        echo "Please confirm the text on the screen of your device"
        # We're too privileged to call meego-confirm-text...
        # Our source is com.nokia.maemo, whilst m-c-t is from an unknown source
        /usr/bin/aegis-exec meego-confirm-text "Attention!" \
          /tmp/busybox-power-error > /dev/null 2>&1
        res=$?
        rm /tmp/busybox-power-error
        if test ! $res == 0; then exit 1; fi
        ;;
      esac
}

# Rollback procedure for Harmattan based devices
ROLLBACK_HARMATTAN() {
    echo -e "\nWarning: an error has occured! Rolling back..."
    $EXECPWR cp -af $TMPBINBAK /bin/busybox
    $EXECPWR cp -a $TMPHASHBAK /var/lib/aegis/refhashlist
    echo "End of roll-back"
    exit 1
}

# Uninstallation of the enhanced binary
UNINSTALL() {
    if test $MODIFIEDBIN == 1; then
      # /bin/busybox has been modified since installing busybox-power
      # Leave both the file and the diversion in place
      return
    fi

    case $ENVIRONMENT in
      SDK|DIABLO|FREMANTLE)
        if test -e $DISTBIN; then
          cp -af $DISTBIN /bin/busybox
          if test -e /bin/busybox; then
            rm $DISTBIN; fi
        elif test "$ENVIRONMENT" == "SDK"; then
          # There was no /bin/busybox to begin with..
          rm /bin/busybox
        fi

        /usr/sbin/dpkg-divert --remove /bin/busybox
        ;;
      HARMATTAN)
        if ! test -e $DISTBIN; then return; fi

        TMPHASHBAK=`$EXECPWR mktemp`
        TMPBINBAK=`$EXECPWR mktemp`
        ORIGINCHECK=`GETORIGINCHECK_STATUS`

        # Useful information for Harmattan-based devices
        ECHO_VERBOSE "refhashlist backup: $TMPHASHBAK"
        ECHO_VERBOSE "busybox backup: $TMPBINBAK"
        ECHO_VERBOSE "instbinary: $INSTBINARY_SHA1"
        ECHO_VERBOSE "origbinary: $ORIGBINARY_SHA1"
        ECHO_VERBOSE "device mode: $DEVICEMODE"
        ECHO_VERBOSE "origincheck: $ORIGINCHECK"

        if test $ORIGINCHECK -eq 1; then
          SETORIGINCHECK_STATUS 0; fi

        $EXECPWR cp -a /bin/busybox $TMPBINBAK || exit 1
        $EXECPWR cp -a /var/lib/aegis/refhashlist $TMPHASHBAK || exit 1
        $EXECPWR cp -af $DISTBIN /bin/busybox || ROLLBACK_HARMATTAN
        $EXECPWR sed -i "s/$INSTBINARY_SHA1/$ORIGBINARY_SHA1/" /var/lib/aegis/refhashlist || ROLLBACK_HARMATTAN
        /usr/bin/accli -c tcb-sign -F /var/lib/aegis/refhashlist < /var/lib/aegis/refhashlist || ROLLBACK_HARMATTAN
        /usr/sbin/validator-init

        if test $ORIGINCHECK -eq 1; then
          SETORIGINCHECK_STATUS 1; fi

        rm $TMPBINBAK
        rm $TMPHASHBAK
        rm $DISTBIN
        ;;
    esac
}

# Remove all symlinks that the installation script has made
UNSYMLINK() {
    # Load list of installed symlinks
    touch $INSTALLDIR/busybox-power.symlinks
    source $INSTALLDIR/busybox-power.symlinks

    # Walk through all possible destinations
    for DESTDIR in $DESTINATIONS; do 
      # Enable us to see all entries in $DESTINATIONS as variables
      eval "APPLICATIONS=\$$DESTDIR"
      # Set destination directory accordingly
      case $DESTDIR in
        DEST_BIN)
          DIR="/bin"
          ;;
        DEST_SBIN)
          DIR="/sbin"
          ;;
        DEST_USRBIN)
          DIR="/usr/bin"
          ;;
        DEST_USRSBIN)
          DIR="/usr/sbin"
          ;;
      esac

      ECHO_VERBOSE "\nRemoving symlinks in $DIR"
      # Walk through all applications from the current destination
      for APP in $APPLICATIONS; do
        # The following code is executed for every application in the current
        # destination
        if test -h $DIR/$APP; then 
          # Good, this app is still a symbolic link ..
          if test -n "`ls -l $DIR/$APP | grep busybox`"; then
            ECHO_VERBOSE "Removing link: $DIR/$APP"
            rm $DIR/$APP
          fi
        fi
      done
    done
}

# Action to be performed after restoring original busybox
CLEANUP() {
    OLDFILES="busybox-power.symlinks
      busybox.distrib.version
      busybox.distrib.sha1"

    for file in $OLDFILES; do
      if test -e $INSTALLDIR/$file; then
        rm $INSTALLDIR/$file
      fi
    done

    # Clean up trap (from busybox-power <= 1.20.2power1)
    # Should be removed by the old prerm, but may be left behind when that one
    # fails and dpkg uses this one instead. Therefore, keep this cleanup
    # included for a few busybox-power releases.
    line="trap exit SIGHUP #by busybox-power"
    if grep -F -q "$line" /etc/profile; then
      sed "/$line/d" /etc/profile > /tmp/profile.sed
      mv /tmp/profile.sed /etc/profile
    fi
}

### Codepath ###
ECHO_VERBOSE "busybox-power: verbose mode"
ECHO_VERBOSE "  binary: $EXECPWR"
ECHO_VERBOSE "  version string: `$EXECPWR | $EXECPWR head -n 1`"
CHECK_ENV && ECHO_VERBOSE "  environment: $ENVIRONMENT"

CHECK_SYMLINKSFILE
if test "$ENVIRONMENT" != "SDK"; then
  CHECK_ROOT
fi
CHECK_BACKUP
CHECK_INSTALLEDBIN
if test -e /tmp/busybox-power-error; then
  # An error has occured during the checks
  DISPLAY_ERRORS
fi
UNSYMLINK
UNINSTALL
CLEANUP