#!/bin/sh

. /etc/default/rcS

CFGDIR="/etc/default/volatiles"
TMPROOT="/var/tmp"
COREDEF="00_core"

[ "${VERBOSE}" != "no" ] && echo "Populating volatile Filesystems."

create_file() {
	EXEC="
	touch \"$1\";
	chown ${TUSER}.${TGROUP} $1 || echo \"Failed to set owner -${TUSER}- for -$1-.\" >/dev/tty0 2>&1;
	chmod ${TMODE} $1 || echo \"Failed to set mode -${TMODE}- for -$1-.\" >/dev/tty0 2>&1 "

	test "$VOLATILE_ENABLE_CACHE" = yes && echo "$EXEC" >> /etc/volatile.cache

	[ -e "$1" ] && {
	  [ "${VERBOSE}" != "no" ] && echo "Target already exists. Skipping."
	} || {
	  eval $EXEC
	}
}

mk_dir() {
	EXEC="
	mkdir -p \"$1\";
	chown ${TUSER}.${TGROUP} $1 || echo \"Failed to set owner -${TUSER}- for -$1-.\" >/dev/tty0 2>&1;
	chmod ${TMODE} $1 || echo \"Failed to set mode -${TMODE}- for -$1-.\" >/dev/tty0 2>&1 "

	test "$VOLATILE_ENABLE_CACHE" = yes && echo "$EXEC" >> /etc/volatile.cache

	[ -e "$1" ] && {
	  [ "${VERBOSE}" != "no" ] && echo "Target already exists. Skipping."
	} || {
	  eval $EXEC
	}
}

link_file() {
	EXEC="test -e \"$2\" -o -L $2 || ln -s \"$1\" \"$2\" >/dev/tty0 2>&1"

	test "$VOLATILE_ENABLE_CACHE" = yes && echo "	$EXEC" >> /etc/volatile.cache

	[ -e "$2" ] && {
	  echo "Cannot create link over existing -${TNAME}-." >&2
	} || {
	  eval $EXEC
	}
}

check_requirements() {

  cleanup() {
    rm "${TMP_INTERMED}"
    rm "${TMP_DEFINED}"
    rm "${TMP_COMBINED}"
    }

  CFGFILE="$1"

  [ `basename "${CFGFILE}"` = "${COREDEF}" ] && return 0

  TMP_INTERMED="${TMPROOT}/tmp.$$"
  TMP_DEFINED="${TMPROOT}/tmpdefined.$$"
  TMP_COMBINED="${TMPROOT}/tmpcombined.$$"


  cat /etc/passwd | sed 's@\(^:\)*:.*@\1@' | sort | uniq > "${TMP_DEFINED}"
  cat ${CFGFILE} | grep -v "^#" | cut -d " " -f 2 > "${TMP_INTERMED}"
  cat "${TMP_DEFINED}" "${TMP_INTERMED}" | sort | uniq > "${TMP_COMBINED}"

  NR_DEFINED_USERS="`cat "${TMP_DEFINED}" | wc -l`"
  NR_COMBINED_USERS="`cat "${TMP_COMBINED}" | wc -l`"

  [ "${NR_DEFINED_USERS}" -ne "${NR_COMBINED_USERS}" ] && {
    echo "Undefined users:"
    diff "${TMP_DEFINED}" "${TMP_COMBINED}" | grep "^>"
    cleanup
    return 1
    }


  cat /etc/group | sed 's@\(^:\)*:.*@\1@' | sort | uniq > "${TMP_DEFINED}"
  cat ${CFGFILE} | grep -v "^#" | cut -d " " -f 3 > "${TMP_INTERMED}"
  cat "${TMP_DEFINED}" "${TMP_INTERMED}" | sort | uniq > "${TMP_COMBINED}"

  NR_DEFINED_GROUPS="`cat "${TMP_DEFINED}" | wc -l`"
  NR_COMBINED_GROUPS="`cat "${TMP_COMBINED}" | wc -l`"

  [ "${NR_DEFINED_GROUPS}" -ne "${NR_COMBINED_GROUPS}" ] && {
    echo "Undefined groups:"
    diff "${TMP_DEFINED}" "${TMP_COMBINED}" | grep "^>"
    cleanup
    return 1
    }

  # Add checks for required directories here

  cleanup
  return 0
  }

apply_cfgfile() {

  CFGFILE="$1"

  check_requirements "${CFGFILE}" || {
    echo "Skipping ${CFGFILE}"
    return 1
    }

  cat ${CFGFILE} | grep -v "^#" | \
  while read LINE; do

    eval `echo "$LINE" | sed -n "s/\(.*\)\ \(.*\) \(.*\)\ \(.*\)\ \(.*\)\ \(.*\)/TTYPE=\1 ; TUSER=\2; TGROUP=\3; TMODE=\4; TNAME=\5 TLTARGET=\6/p"`

    [ "${VERBOSE}" != "no" ] && echo "Checking for -${TNAME}-."


    [ "${TTYPE}" = "l" ] && {
      TSOURCE="$TLTARGET"
      [ -L "${TNAME}" ] || {
	[ "${VERBOSE}" != "no" ] && echo "Creating link -${TNAME}- pointing to -${TSOURCE}-."
	link_file "${TSOURCE}" "${TNAME}"
	}
      continue
      }

    [ -L "${TNAME}" ] && {
      [ "${VERBOSE}" != "no" ] && echo "Found link."
      NEWNAME=`ls -l "${TNAME}" | sed -e 's/^.*-> \(.*\)$/\1/'`
      echo ${NEWNAME} | grep -v "^/" >/dev/null && {
	TNAME="`echo ${TNAME} | sed -e 's@\(.*\)/.*@\1@'`/${NEWNAME}"
	[ "${VERBOSE}" != "no" ] && echo "Converted relative linktarget to absolute path -${TNAME}-."
	} || {
	TNAME="${NEWNAME}"
	[ "${VERBOSE}" != "no" ] && echo "Using absolute link target -${TNAME}-."
	}
      }

    case "${TTYPE}" in
      "f")  [ "${VERBOSE}" != "no" ] && echo "Creating file -${TNAME}-."
	    create_file "${TNAME}"
	    ;;
      "d")  [ "${VERBOSE}" != "no" ] && echo "Creating directory -${TNAME}-."
	    mk_dir "${TNAME}"
	    # Add check to see if there's an entry in fstab to mount.
	    ;;
      *)    [ "${VERBOSE}" != "no" ] && echo "Invalid type -${TTYPE}-."
	    continue
	    ;;
    esac


    done

  return 0

  }

SKEL_DIR="/etc/volatile/skel"

skel_mount() {
	VOLATILE="$1"

	[ -d "$VOLATILE" ] || mkdir -p "$VOLATILE"

	mount -t tmpfs volatile "$VOLATILE" -omode=0755
}

skel_load() {
	VOLATILE="$1"

	if ! skel_mount "$VOLATILE"; then
		echo "failed to mount $VOLATILE"
		return 1
	fi

	cp -a "$SKEL_DIR"/* "$VOLATILE"/
}

skel_update() {
	VOLATILE="$1"

	if ! skel_mount "$VOLATILE"; then
		echo "failed to update"
		return 1
	fi

	echo -n "Populating volatile directory..."
	for file in `ls -1 "${CFGDIR}" | sort`; do
		apply_cfgfile "${CFGDIR}/${file}"
	done
	echo "done"

	if [ -d "$SKEL_DIR" ]; then
		rm -rf "$SKEL_DIR"
	fi

	mkdir -p "$SKEL_DIR"/tmp
	cp -a "$VOLATILE"/* "$SKEL_DIR"/
}

populate() {
	if [ -d "$SKEL_DIR"/tmp ]; then
		skel_load /var/volatile
	else
		skel_update /var/volatile
	fi

	for d in /var/volatile/*
	do
		ln -sf "$d" /var
	done

	if ! test -L /tmp; then
		rm -rf /tmp
		ln -sf /var/tmp /tmp
	fi
}

case "$1" in
	start)
	if grep -q "^volatile " /proc/mounts; then
		echo "volatile directory is already mounted"
	else
		populate
	fi
	;;
	stop)
	: # no-op
	;;
	update)
	if skel_update /var/volatile; then
		umount /var/volatile
		if grep -q "^volatile " /proc/mounts; then
			cp -a "$SKEL_DIR"/* /var/volatile
		fi
	fi
	;;
	*)
	echo "Usage: /etc/init.d/populate-volatile {start|stop|update}"
	;;
esac

: exit 0