#! /bin/sh
#
# adduser 2.0: a utility to add users to the system
#
# Copyright (C) 1998 Todd Robinson <mtrob@tampabay.rr.com>
# Copyright (C) 1994 Ian A. Murdock <imurdock@shell.portal.com>
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
# Originally for the Debian Linux distribution (01/21/94).  Feel free to use
# it in YOUR distribution, too. :)  Please note that this is just a simple
# script that _somewhat_ automates the really boring and repetitive task
# of creating new user accounts.  It makes no attempt to be sophisticated.
# Let me know if you improve it in any way.
#
# I need to write a man page for this.
#
# Modified by Marc Ewing <marc@redhat.com> for RHS Linux
# 12/05/98 Modified by Todd Robinson to add command line options:
#   -g <group>     adds the new user to the indicated group
#                  default: users
#   -d <home_dir>  makes the indicated directory the users home
#                  default: /home/'user name'
#   -h c|f|m       disable c)reation of home directory
#                  disable f)illing of home directory from /etc/skel
#                  disable m)ail box setup (sendmail)
#   -n <user_name> users real name or relevant comment
#                  default: 'RH Linux User'
#   -s <shell>     makes the indicated program the users shell
#                  default: /bin/bash

# Everything happens too fast, so don't let the user interrupt.
trap "" 1 2 3 15

# Set a few important variables before getting started.
NUMARG=$#
EXIST=0

PASSWD="/etc/passwd"
PBAK="/etc/passwd-"		# Some programs use /etc/passwd-, others use
				# /etc/passwd.OLD.  Take your pick.

GROUP_FILE="/etc/group"
GROUP_FILE_BAK="/etc/group-"
GROUP="users"

PLOCK="/etc/ptmp"		# Standard method of locking the password file.

NAME="RH Linux User"
NEW_SHELL="/bin/bash"
HOME_BASE="/home"
SKEL="/etc/skel"
SPOOL="/var/spool/mail"
FIRST_UID=500
CREATE_HOME=1
FILL_HOME=1
MAKE_MAIL=1
ARG_ERR=0

# A few sanity checks...
if [ `id -u` != 0 ]; then
	echo "Only root may add users to the system." ; exit 1
fi

if [ $NUMARG = 0 ]
then
   ARG_ERR=1
fi

# Get command line options if any
while getopts d:g:h:n:s option
do
   case $option in
   g) GROUP=$OPTARG;;
   d) HOME_DIR=$OPTARG;;
   n) NAME=$OPTARG;;
   h) case $OPTARG in
      c) CREATE_HOME=0;;
      f) FILL_HOME=0;;
      m) MAKE_MAIL=0;;
      *) ARG_ERR=3;;
      esac;;
   s) NEW_SHELL=$OPTARG;;
   *) ARG_ERR=2;;
   esac
done
shift `expr $OPTIND - 1`
if [ $# -ne 1 ]
then
   echo "$0: no user name specified, or invalid argument count"
   ARG_ERR=4
fi

if [ $ARG_ERR -gt 0 ]
then
   echo "Usage: adduser [ -g <group> ][ -d <home dir> ][ -h c|f|m ]"
   echo "               [ -n <full name> ][ -s <shell> ] <user name>"
   echo $ARG_ERR
   exit 1
fi

NEW_USER="$1"

if [ -z $HOME_DIR ]
then
   HOME_DIR=$HOME_BASE/$NEW_USER
fi

id $NEW_USER >/dev/null 2>/dev/null && EXIST=1

if [ $EXIST = 1 ]; then
   echo "The login $NEW_USER already exists."
   exit 1
fi

if [ -f $PLOCK ]; then
   echo "$PASSWD is locked.  Try again later."
   exit 1
fi

# And now the program begins: 
echo "" ; echo -n "Looking for first available UID..."
NUID=`cut -f 3 -d ":" $PASSWD | sort -n | awk -v uid=$FIRST_UID '
		{ if ($1 == uid) uid = uid + 1; }
END		{ print uid; }
'`

if [ $NUID -ge 65536 ]
then
   echo ""
   echo "*** Sorry, ran out of uids."
   exit 1
fi
echo " $NUID"


echo -n "Looking for Group $GROUP GID..."
NGID=`grep $GROUP $GROUP_FILE |cut -f 3 -d ":"`
if [ -z $NGID ]
then
   echo ""
   echo "*** Sorry, can't find Group: $GROUP"
   exit 1
fi
echo " $NGID"

echo "" ; echo -n "Adding login: $NEW_USER..."
touch $PLOCK ;

cp $PASSWD $PBAK
echo "$NEW_USER:*:$NUID:$NGID:$NAME:$HOME_DIR:$NEW_SHELL" >> $PASSWD

# Add new user to selected group
cp $GROUP_FILE $GROUP_FILE_BAK
sed "s/^\($GROUP.*[^:]\)\$/\1,$NEW_USER/" < $GROUP_FILE_BAK |
sed "s/^\($GROUP.*:\)\$/\1$NEW_USER/" > $GROUP_FILE

#sed "s/^\(users.*[^:]\)$/\1,$LOGIN/" < $GBAK |
#sed "s/^\(users.*:\)$/\1,$LOGIN/" > $GROUP

#echo "$LOGIN::$NGID:$LOGIN" >> $GROUP

rm -f $PLOCK
echo "done."

if [ $CREATE_HOME -eq 1 ]
then
   echo -n "Creating home directory: $HOME_DIR..."
   mkdir $HOME_DIR
   chmod 2775 $HOME_DIR
   if [ $FILL_HOME -eq 1 ]
   then
      cp -a $SKEL/.??* $SKEL/* $HOME_DIR >/dev/null 2>/dev/null
      chown -R $NUID.$NGID $HOME_DIR
   fi
   echo "done."
fi

if [ $MAKE_MAIL -eq 1 ]
then
   echo -n "Creating mailbox: $SPOOL/$NEW_USER..."
   touch $SPOOL/$NEW_USER
   chmod 660 $SPOOL/$NEW_USER
   chown $NUID.mail $SPOOL/$NEW_USER
   echo "done."
fi

echo ""
echo "Don't forget to set the password."

exit 0