#!/usr/bin/perl

use File::Basename;

#the command you want to use in the chroot environment
my @command = qw(bash cat chmod cp id ls mkdir mv nslookup perl ping pwd rm rmdir rsync scp sh ssh ssh-keygen vi);

my ($homedir, $shell);

print "Username: ";
my $username = <STDIN>;
chomp $username;

#Check if the specified user already exists
my $user_status;
my @etc_passwd = `cat /etc/passwd`;
foreach (@etc_passwd){
	chomp $_;
	my($etc_username, $etc_homedir, $etc_shell) = (split(/:/, $_))[0,5,6];
	chomp($etc_username, $etc_homedir, $etc_shell);
	if( $etc_username eq $username ){
		$user_status = 1;	
		$homedir = $etc_homedir;
		$shell = $etc_shell;
	}
}

#For existing user
if($user_status){
	my $mod_user;
	until($mod_user =~ /(Y|N)/){
		print "$username already exists. Set chroot for this user? (Y/N): ";
		$mod_user = <STDIN>;
		chomp $mod_user;
	}

	if($mod_user eq 'Y'){
		print "usermod -d $homedir/\./ $username\n";
		`usermod -d $homedir/\./\ $username`;
	}

	exit if($mod_user eq 'N');
}

#For new user
else{
	print "Shell (/bin/bash): ";
	$shell = <STDIN>;
	chomp $shell;

	print "Home Directory (/home/USRENAME): ";
	$homedir = <STDIN>;
	chomp $homedir;

	if(!$homedir){
		$homedir = '/home' . "/$username";
	}
	
	my $chroot_homedir = "$homedir" . '/./';
	
	#Create user's home directory
	if(!-d "$homedir"){
	print "making homedirectory...";
	`mkdir $homedir`;
	print "done\n";
	}

	#Add user
	print "Adding User...";

	if($shell){
		`useradd -s $shell -d $chroot_homedir $username`;
		print "done\n";
	}

	else{
		`useradd -d $chroot_homedir $username`;
		print "done\n";
	}

	#Change Password
	`passwd $username`;

	#Change the directory permission
	`chown $username:$username $homedir`;
}


#change directory
chdir($homedir);

#Remove the dot file
`ls -A |xargs rm -f`;

#Create the top directory
`mkdir bin`;
`mkdir etc`;
`mkdir dev`;
`mkdir -p usr/bin`;
`mkdir -p usr/libexec`;
`mkdir -p usr/local/bin`;

#set ~/usr/bin/groups
open(OUT, "> usr/bin/groups");
print OUT "#!/bin/bash\n\n";
print OUT "id -Gn\n";
close(OUT);
`chmod 755 usr/bin/groups`;

#create passwd and group files
`grep /etc/passwd -e "^root" -e "^$username" > etc/passwd`;
`grep /etc/group -e "^root" -e "^$username" > etc/group`;

#Copy specified commands and required libraries
foreach (@command){
	chomp $_;	
	my $command = `which $_`;
	chomp $command;

	#Copy specified commands
	`cp $command \.$command`;

	#check the associated libs
	my @libs = `ldd $command`;
	foreach my $lib (@libs){
		chomp $lib;
		$lib =~ s/^\s+(.*)\(.*\)/$1/g;

		if($lib =~ /=> /){
			$lib =~ s/=> //g;
			$lib = (split(/ /, $lib))[1];
		}
		
		#check if the parent directory exists
		my ($filename, $path) = (fileparse($lib))[0,1];
		chomp $filename;
		chomp $path;

		if(!-d "\.$path"){
			print "mkdir -p \.$path\n";
			`mkdir -p \.$path`;
		}

		#Copy the required libraries
		if(!-f "\.$lib"){
			print "cp $lib \.$lib\n";
			`cp $lib \.$lib`;
		}
	}
}

#Copy the static libraries
print "Copy /lib/libnss_*\n";
`cp /lib/libnss_* lib/`;

#copy sftp-server program
if (-f "/usr/libexec/sftp-server") {
	print "cp /usr/libexec/sftp-server usr/libexec/sftp-server\n";
	`cp /usr/libexec/sftp-server usr/libexec/sftp-server`;	
}

else{
	print "/usr/libexec/sftp-server not found!!\n";
}

#copy /etc/resolv.conf
print "Copy /etc/resolv.conf\n";
`cp /etc/resolv.conf ./etc`;

#make special file

#make dev/zero
my($zero1, $zero2) = ((split/,/, `ls -alh /dev/zero |awk '{ print \$5 \$6 }'`));
print "mknod -m 666 dev/zero c $zero1 $zero2\n";
`mknod -m 666 dev/zero c $zero1 $zero2`;

#make dev/null
my($null1, $null2) = ((split/,/, `ls -alh /dev/null |awk '{ print \$5 \$6 }'`));
print "mknod -m 666 dev/null c $null1 $null2\n";
`mknod -m 666 dev/null c $null1 $null2`;