#!/bin/sh

set -e

# editing nsswitch.conf seems to be ok
# http://lists.debian.org/debian-devel/2007/02/msg00076.html

# check whether the name is configure to do lookups through
# LDAP
# Note: this function is in libnss-ldapd.postinst and libnss-ldapd.postrm
nss_is_enabled()
{
  name="$1"
  grep -q '^[[:space:]]*'$name'[[:space:]]*:.*ldap.*' /etc/nsswitch.conf
}

# check to see if name is configured to do lookups through
# LDAP and enable if not
nss_enable()
{
  name="$1"
  if ! nss_is_enabled "$name"
  then
    echo "/etc/nsswitch.conf: enable LDAP lookups for $name" >&2
    if grep -q '^[[:space:]]*'$name'[[:space:]]*:' /etc/nsswitch.conf
    then
      # modify an existing entry by just adding ldap to the end
      sed -i 's/^\([[:space:]]*'$name'[[:space:]]*:.*[^[:space:]]\)[[:space:]]*$/\1 ldap/' /etc/nsswitch.conf
    else
      # append a new line
      printf '%-15s ldap\n' $name':' >> /etc/nsswitch.conf
    fi
    # invalidate nscd cache
    nscd -i "$name" > /dev/null 2>&1 || true
  fi
  # we're done
  return 0
}

# remove NSS lookups though LDAP for the specified service
# Note: this function is in libnss-ldapd.postinst and libnss-ldapd.postrm
nss_disable()
{
  name="$1"
  # these functions also remove the lookup result handling part
  # of the ldap entry (see nsswitch.conf(5))
  if nss_is_enabled "$name"
  then
    echo "/etc/nsswitch.conf: disable LDAP lookups for $name" >&2
    if [ -n "`sed -n '/^[[:space:]]*'$name'[[:space:]]*:[[:space:]]*ldap[[:space:]]*\(\[[^]]*\]\)*[[:space:]]*$/p' /etc/nsswitch.conf`" ]
    then
      # the name service only maps to ldap, remove the whole line
      sed -i '/^[[:space:]]*'$name'[[:space:]]*:[[:space:]]*ldap[[:space:]]*\(\[[^]]*\]\)*[[:space:]]*$/d' /etc/nsswitch.conf
    else
      # remove ldap part from existing line, keeping other methods intact
      # TODO: remove trailing space
      sed -i 's/^\([[:space:]]*'$name'[[:space:]]*:.*\)ldap[[:space:]]*\(\[[^]]*\]\)*[[:space:]]*\(.*\)$/\1\3/' /etc/nsswitch.conf
    fi
    # invalidate nscd cache
    nscd -i "$name" > /dev/null 2>&1 || true
  fi
  # we're done
  return 0
}

# real functions begin here
if [ "$1" = "configure" ]
then
  # get configuration data from debconf
  . /usr/share/debconf/confmodule
  # modify /etc/nsswitch.conf
  db_get libnss-ldapd/nsswitch
  enablenss=`echo "$RET" | sed 's/,//g'`
  for n in aliases ethers group hosts netgroup networks passwd protocols rpc services shadow
  do
    if echo ' '$enablenss' ' | grep -q ' '$n' '
    then
      nss_enable $n
    else
      nss_disable $n
    fi
  done
  # we're done
  db_stop
fi

#DEBHELPER#

exit 0