#!/bin/sh

set -e

CONFFILE="/etc/nss-ldapd.conf"

# set an option in the configuration file to the specified value
cfg_set()
{
  parameter="$1"
  value="$2"
  # make matching of spaces better in parameter
  # this is complicated becase of the "base [map] dn" keyword
  param_re=`echo "$parameter" | sed 's#^#[[:space:]]*#;s#[[:space:]][[:space:]]*#[[:space:]][[:space:]]*#g'`
  # lines to not match
  nomatch_re="^$param_re[[:space:]][[:space:]]*\(aliases\|ethers\|group\|hosts\|netgroup\|networks\|passwd\|protocols\|rpc\|services\|shadow\)"
  # check if the parameter is defined
  line=`sed -n '/'"$nomatch_re"'/n;/^'"$param_re"'[[:space:]]/p' "$CONFFILE" | head -n 1`
  if [ -z "$line" ]
  then
    # check if the parameter is commented out
    param_re="#$param_re"
    nomatch_re="^$param_re[[:space:]][[:space:]]*\(aliases\|ethers\|group\|hosts\|netgroup\|networks\|passwd\|protocols\|rpc\|services\|shadow\)"
    line=`sed -n '/'"$nomatch_re"'/n;/^'"$param_re"'[[:space:]]/p' "$CONFFILE" | head -n 1`
  fi
  # decide what to do
  if [ -z "$line" ]
  then
    # just append a new line
    echo "$parameter $value" >> $CONFFILE
  else
    # escape line to replace
    replace=`echo "$line" | sed 's#\\\#\\\\\\\#g;s#\([.*+?^$|]\)#\\\\\1#g'`
    # escape value (parameter doesn't have any special stuff)
    value=`echo "$value" | sed 's#\\\#\\\\\\\#g;s#|#\\\|#g;s#&#\\\&#g'`
    # replace the first occurrence of the line
    sed -i '1,\|^'"$replace"'$| s|^'"$replace"'$|'"$parameter"' '"$value"'|i' "$CONFFILE"
  fi
  # we're done
  return 0
}

# disable an option in the configuration file by commenting it out
cfg_disable()
{
  parameter="$1"
  # make matching of spaces better in parameter
  param_re=`echo "$parameter" | sed 's#^#[[:space:]]*#;s#[[:space:]][[:space:]]*#[[:space:]][[:space:]]*#g'`
  # lines to not match
  nomatch_re="^$param_re[[:space:]][[:space:]]*\(aliases\|ethers\|group\|hosts\|netgroup\|networks\|passwd\|protocols\|rpc\|services\|shadow\)"
  # comment out the option
  sed -i '/'"$nomatch_re"'/n;s/^'"$param_re"'[[:space:]].*$/#&/i' "$CONFFILE"
  # we're done
  return 0
}

# set the list of uris
cfg_uris()
{
  uris="$1"
  # escape all uri directives
  sed -i 's/^uri /_uri_ /i' $CONFFILE
  # set the uri options
  echo "$uris" | sed 's/  */\n/g' | while read uri
  do
    if grep -qi '^_uri_ ' $CONFFILE
    then
      # escape uri for use in regexp replacement
      uri=`echo "$uri" | sed 's#\\\#\\\\\\\#g;s#|#\\\|#g;s#&#\\\&#g'`
      # replace the first occurrence of _uri_
      sed -i '1,/^_uri_ / s|^_uri_ .*$|uri '"$uri"'|i' "$CONFFILE"
    else
      # append new uri
      echo "uri $uri" >> $CONFFILE
    fi
  done
  # comment out the remaining escaped uris
  sed -i 's/^_uri_ /#uri /' $CONFFILE
}

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

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

# remove NSS lookups though LDAP for the specified service
nss_disable()
{
  name="$1"
  # these functions also remove the lookup result handling part
  # of the ldap entry (see nsswitch.conf(5))
  if grep -q '^'$name':.*ldap.*' /etc/nsswitch.conf
  then
    echo "/etc/nsswitch.conf: disable LDAP lookups for $name" >&2
    if [ -n "`sed -n '/^'$name':[[:space:]]*ldap[[:space:]]*\(\[[^]]*\]\)*[[:space:]]*$/p' /etc/nsswitch.conf`" ]
    then
      # the name service only maps to ldap, remove the whole line
      sed -i '/^'$name':[[: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/^\('$name':.*\)ldap[[:space:]]*\(\[[^]]*\]\)*[[:space:]]*\(.*\)$/\1\3/' /etc/nsswitch.conf
    fi
  fi
  # we're done
  return 0
}

# create a default configuration file if nothing exists yet
create_config()
{
  if [ ! -e "$CONFFILE" ]
  then
    # create a simple configuration file from this template
    # TODO: improve this template
    cat > "$CONFFILE" << EOM
# $CONFFILE
# nss-ldapd configuration file. See nss-ldapd.conf(5)
# for details.

# The user and group nslcd should run as.
uid nslcd
gid nslcd

# The location at which the LDAP server(s) should be reachable.
uri ldap://localhost/

# The search base that will be used for all queries.
base dc=example,dc=net

# The LDAP protocol version to use.
#ldap_version 3

# The DN to bind with for normal lookups.
#binddn cn=annonymous,dc=example,dc=net
#bindpw secret

# The search scope.
#scope sub

EOM
  fi
  # we're done
  return 0
}

# real functions begin here
if [ "$1" = "configure" ]
then
  # get configuration data from debconf
  . /usr/share/debconf/confmodule
  # check if the nslcd user exists
  if getent passwd nslcd >/dev/null
  then
    :
  else
    # create nslcd user and group
    adduser --system --group --home /var/run/nslcd/ \
            --gecos "nss-ldapd name service LDAP connection daemon" \
            --no-create-home \
            nslcd
    # add uid/gid options to the config file if it exists
    # (this is when we're upgrading)
    if [ -f "$CONFFILE" ]
    then
      echo "Adding uid and gid options to $CONFFILE..." >&2
      echo "# automatically added on upgrade of libnss-ldapd package" >> "$CONFFILE"
      cfg_set uid nslcd
      cfg_set gid nslcd
    fi
  fi
  # create a default configuration
  create_config
  # set server uri
  db_get libnss-ldapd/ldap-uris
  cfg_uris "$RET"
  # set search base
  db_get libnss-ldapd/ldap-base
  cfg_set base "$RET"
  # set bind dn/pw
  db_get libnss-ldapd/ldap-binddn
  if [ -n "$RET" ]
  then
    cfg_set binddn "$RET"
    db_get libnss-ldapd/ldap-bindpw
    if [ -n "$RET" ]
    then
      cfg_set bindpw "$RET"
    else
      # no bindpw set
      if grep -i -q "^bindpw " $CONFFILE
      then
        cfg_set bindpw "*removed*"
        cfg_disable bindpw
      fi
    fi
  else
    # no binddn/pw, disable options
    cfg_disable binddn
    if grep -i -q "^bindpw " $CONFFILE
    then
      cfg_set bindpw "*removed*"
      cfg_disable bindpw
    fi
  fi
  # remove password from database
  db_set libnss-ldapd/ldap-bindpw ""
  # modify /etc/nsswitch.conf
  db_get libnss-ldapd/nsswitch
  enablenss=`echo "$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
  # TODO: fix permissions of configfile if passwords are stored
  # TODO: create backups of /etc/nsswitch.conf and configfile
  #       (probably store orig in tmpfile and if diff install it
  #       as backup)
  # restart nscd to pick up changes in nsswitch.conf
  # (other processes will have to be restarted manually)
  if [ -x /etc/init.d/nscd ] && [ `pidof -s nscd` ]
  then
    if which invoke-rc.d >/dev/null 2>&1
    then
      invoke-rc.d nscd restart
    else
      /etc/init.d/nscd restart
    fi
  fi
  # update the cache of the dynamic linker
  # (we don't use dh_makeshlibs because that also installs a shlibs file
  # which we don't need)
  ldconfig
fi

#DEBHELPER#

exit 0