#!/bin/bash
#
# adduser 1.4: a utility to add users to the system
#
# 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.
#
# Written 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 Red Hat Linux
# Modified by Michael K. Johnson <johnsonm@redhat.com> for optional
# shadow password support.
# Modified by Michael K. Johnson <johnsonm@redhat.com> to make it safer

# 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=$#
LOGIN="$1"
EXIST=0

NOHOME="$2"

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

SHADOW="/etc/shadow"
SBAK="/etc/shadow-"
SNEW="/etc/shadow.new"

GROUP="/etc/group"
GBAK="/etc/group-"
GNEW="/etc/group.new"

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

DSHELL="/bin/bash"
DHOME="/home"
SKEL="/etc/skel"
SPOOL="/var/spool/mail"
FIRST_UID=500
FIRST_GID=500

# 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
	echo "You need to specify the login to add; for example, \`adduser redneck'." ; exit 1
# this is the donnie memorial shell script...
fi

if id "$LOGIN" >/dev/null 2>&1 ; then
	echo "User $LOGIN already exists"
	exit 1
fi

if [ $(echo "$LOGIN" | wc -c | tr -d ' ') -gt 9 ] ; then
	# that 9 is intentional -- it counts the newline, too...
	echo "$LOGIN is over eight characters"
	exit 1
fi

if echo "$LOGIN" | grep -q : ; then
	echo "$LOGIN contains a \`:' character"
	exit 1
fi

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

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

if ln $PASSWD $PLOCK; then : ; else
	echo "$PASSWD is locked.  Try again later." ; exit 1
fi

die ()
{
  rm -f $PLOCK
  exit 1
}

# 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 65535 ]; then
	echo "Sorry, ran out of uids."
	die
fi
echo " $NUID"


echo -n "Looking for first available GID..."
NGID=`cut -f 3 -d ":" $GROUP | sort -n | awk -v gid=$FIRST_GID '
		{ if ($1 == gid) gid = gid + 1; }
END		{ print gid; }
'`

if [ $NGID -lt $FIRST_GID ]; then
	NGID=$FIRST_GID
fi

if [ $NGID -ge 65535 ]; then
	echo "Sorry, ran out of gids."
	die
fi
echo " $NGID"

echo "" ; echo -n "Adding login: $LOGIN..."


cp $PASSWD $PBAK || die
cp $PASSWD $PNEW || die
if [ -f "$SHADOW" ] ; then
  echo "$LOGIN:x:$NUID:$NGID:RHS Linux User:$DHOME/$LOGIN:$DSHELL" | \
     cat >> $PNEW || die
  # need cat because echo won't return a return code
  cp $SHADOW $SBAK || die
  cp $SHADOW $SNEW || die
  # The date invocation is non-standard, but works with GNU date.
  # It fills in the "last changed" field with the number of DAYS
  # since epoch (86400 seconds per day; %s is second since epoch).
  echo "$LOGIN:*:$(($(date '+%s')/86400))::::::" | \
    cat >> $SNEW || die
else
  echo "$LOGIN:*:$NUID:$NGID:RHS Linux User:$DHOME/$LOGIN:$DSHELL" | \
    cat >> $PNEW || die
fi

# Add user to users group
cp $GROUP $GBAK || die
cp $GROUP $GNEW || die
sed "s/^\(users:.*[^:]\)\$/\1,$LOGIN/"'
   '"s/^\(users:.*:\)\$/\1$LOGIN/" < $GBAK > $GNEW || die

echo "$LOGIN::$NGID:$LOGIN" | cat >> $GNEW || die

mv $GNEW $GROUP
if [ -f "$SHADOW" ] ; then
  mv $SNEW $SHADOW
fi
mv $PNEW $PASSWD

rm -f $PLOCK
echo "done."

if [ "x$NOHOME" = "x" ]; then
	echo -n "Creating home directory: $DHOME/$LOGIN..."
	mkdir $DHOME/$LOGIN
	chmod 2775 $DHOME/$LOGIN
	cp -a $SKEL/.??* $SKEL/* $DHOME/$LOGIN >/dev/null 2>/dev/null
	chown -R $NUID.$NGID $DHOME/$LOGIN
	echo "done."
fi

echo -n "Creating mailbox: $SPOOL/$LOGIN..."
touch $SPOOL/$LOGIN ; chmod 660 $SPOOL/$LOGIN ; chown $NUID.mail $SPOOL/$LOGIN
echo "done."

echo ""
echo "Don't forget to set the password."
if [ "x$NOHOME" != "x" ]; then
	echo ""
	echo "The home directory for $LOGIN was set to $DHOME/$LOGIN but the directory"
	echo "was not created.  Be sure that you set it up properly."
fi

#passwd $LOGIN
#chfn $LOGIN

# EOF