linfreeze

#!/bin/bash -e
#
#   linfreeze - Utility to prevent permanent file changes.
#
#   Copyright (C) 2010 Ryan Peters <sloshy45 [--at--] sbcglobal [--dot--] net>
#
#   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 3 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, see <http://www.gnu.org/licenses/>.
#
#   Additional permission under GNU GPL version 3 section 7
#
#   If you modify this Program, or any covered work, by linking or 
#   combining it with [name of library] (or a modified version of that library), 
#   containing parts covered by the terms of [name of library's license],
#   the licensors of this Program grant you additional permission to convey
#   the resulting work. {Corresponding Source for a non-source form of such
#   a combination shall include the source code for the parts of [name of library]
#   used as well as that of the covered work.}
#

# Constants
TEXTDOMAINDIR=/usr/local/share/locale
TEXTDOMAIN=linfreeze
PROGNAME=linfreeze
NAMEPROPER=LinFreeze
VERSION=0.9.4
FROZNAME="/etc/.dynamic"	# File listing the dynamic folders for frozen dirs.
STATNAME="/etc/.static"		# File listing the static folders for frozen users/dirs.
LISTNAME="/etc/.frozdirs"	# File listing the frozen users/dirs.
SPECDNAME="/etc/.spec-dy"	# File listing users'/dirs' dynamic directories to be removed.
SPECSNAME="/etc/.spec-stat"	# File listing users'/dirs' static directories to be removed.

# Functions

usage() {
echo $"$NAMEPROPER $VERSION -- Utility to prevent permanent file changes."
echo ""
echo $"WARNING: While in use, this program makes changes to /etc/fstab."
echo $"Do not edit these files while a system is frozen, only before and after."
echo ""
echo $"Usage:"
echo $"$PROGNAME [option] [directory or user to freeze or unfreeze]"
echo
echo $"Options:"
echo $"-h	Display this help message and exit."
echo $"-v	Display version information and exit."
echo ""
echo $"-d	Freeze a directory to prevent permanent file changes."
echo $"-f	Freeze a user account to prevent permanent file changes."
echo $"-u	Unfreeze all directories and users."
echo $"-s	Unfreeze a specific user or directory."
echo $"-c	Remove the temporary directories for user accounts and/or directories."
echo $"-l	Lists the frozen users and directories."
}

ifroot() { # Checks if the current user is 'root', which is needed for this utility.
if [ "$(whoami)" != "root" ];
	then
		echo $"You must be the 'root' user to use this utility."
		exit 1
fi
}

checkcmdline() { #Checks if aufs=tmpfs parameter is up. If not, probably the system can't mount the dir/partition.
if ! [ `cat /proc/cmdline | grep "aufs=tmpfs"` ];
	then
		echo $"Remember to set aufs=tmpfs on kernel parameters to AVOID PROBLEMS. Example: ... ro quiet splash aufs=tmpfs ..."
fi
}

checkfiles() { # Checks if /etc/.frozen exists and renames it to /etc/.dynamic.
ifroot
if [ -f /etc/.frozen ];
	then
		cp /etc/.frozen $FROZNAME
		rm /etc/.frozen
fi
}

directory() { # Recursively freezes an individual folder
ifroot
DIRF=`echo "$OPTARG" | sed -e "s/\/*$//" ` # Removes the trailing slash of $OPTARG
if [ ! -d $DIRF ];
	then
		echo $"Directory $DIRF does not exist!"
		echo $"Please enter an existing directory or create it with 'mkdir $DIRF'."
		exit 1
fi
if [ -d $DIRF.dynamic ];
	then
		echo $"This directory is already frozen! Unfreeze it with $PROGNAME -u."
		echo $"If $DIRF is not frozen, use $PROGNAME -c to remove the temporary directory."
		exit 1
fi
checkfiles
if [ ! -f $FROZNAME ];
	then
		touch $FROZNAME
fi
if [ ! -f /etc/fstab.thaw ];
	then
		cp /etc/fstab /etc/fstab.thaw
fi
mkdir $DIRF.dynamic
echo $"$DIRF.dynamic" >> $FROZNAME
echo $"Making dynamic directory at $OPTARG.dynamic for temporary files..."
echo $DIRF >> $LISTNAME
echo tmpfs $DIRF.dynamic tmpfs defaults,noatime,uid=1000,gid=1000 0 0 >> /etc/fstab
if [ ! -d $DIRF.static ]
	then
		echo $"Would you like to create a directory for read-only files to be laid"
		echo -n $"over the original directory at $DIRF.static? [Y/n]: "
		read STATYES
		echo ""
fi
if [ -d $DIRF.static ];
	then
		touch $STATNAME
		echo $DIRF.static >> $STATNAME
		echo none $DIRF aufs br=$DIRF.dynamic=rw:$DIRF.static=ro:$DIRF=ro 0 0 >> /etc/fstab
		echo $"Folder $DIRF is now frozen. Reboot your computer to not make any changes."
		echo ""
		echo $"If you wish to put temporary files and/or folders in the 'static' directory, please do so now by putting them in $DIRF.static."
		STATYES=N
fi
if [ "$STATYES" = "Y" -o "$STATYES" = "y" ]
	then
		mkdir $DIRF.static
		touch $STATNAME
		echo $DIRF.static >> $STATNAME
		echo none $DIRF aufs br=$DIRF.dynamic=rw:$DIRF.static=ro:$DIRF=ro 0 0 >> /etc/fstab
		echo $"Folder $DIRF is now frozen. Reboot your computer to not make any permanent changes."
		echo ""
		echo $"If you wish to put temporary files and/or folders in the static directory, please do so now by putting them in $DIRF.static."
		echo ""
		echo $"If you would like to 'freeze' other directories or users, you may do so."
		echo ""
	else
		echo none $DIRF aufs br=$DIRF.dynamic=rw:$DIRF=ro 0 0 >> /etc/fstab
		echo $"Folder $DIRF is now 'frozen'. Reboot your computer to not make any permanent changes."
		echo ""
		echo "If you would like to 'freeze' other directories or users, you may do so."
		echo ""
fi
chowndir
if [ -d /home/$CHOWNUSER ];
	then
		chown $CHOWNUSER $DIRF.dynamic
		[ -d $DIRF.static ] && chown $CHOWNUSER $DIRF.static
		RETRY=N
		echo $"Directory permissions changed successfully."
	else
		echo -n "User $CHOWNUSER does not exist!"
		echo $"Use 'chown [user] $DIRF.dynamic' and 'chown [user] $DIRF.static' to set permissions."
		echo $"Exiting..."
fi
checkcmdline
}

chowndir() { # Changes ownership of temporary directories
ifroot
echo $"Would you like to set the ownership of the temporary directories used for 'freezing'?"
echo -n $"This is necessary if the directory frozen was inside of a home directory. [Y/n]: "
read CHOWNYES
echo ""
if [ "$CHOWNYES" = "Y" -o "$CHOWNYES" = "y" ];
	then
		echo -n $"Which user would you like to own the temporary directories?"
		read CHOWNUSER
		echo ""
	else
		echo "Exiting..."
		exit 0
fi
}

user() { # This freezes the user account if the proper directories are in place.
ifroot
if [ ! -d /home/$OPTARG ];
	then
		echo $"User account $OPTARG does not exist! Create it first."
		exit 1
fi
if [ ! -d /home/$OPTARG.dynamic ];
	then
		prep;
	else
		echo $"User account $OPTARG is already frozen!"
		echo "Exiting..."
		exit 1
fi
if [ ! -d "/home/$OPTARG.static" -a "$STATNO" = "Y" ];
	then
		echo "Would you like to create a directory for read-only files to be laid"
		echo -n $"over the original user directory at /home/$OPTARG.static? [Y/n]: "
		read STATIC
		echo ""
fi
if [ "$STATIC" = "Y" -o "$STATIC" = "y" ];
	then
		prep;
fi
if [ ! -f /etc/fstab.thaw ];
	then
		cp /etc/fstab /etc/fstab.thaw
fi
echo tmpfs /home/$OPTARG.dynamic tmpfs defaults,noatime,uid=1000,gid=1000 0 0 >> /etc/fstab
if [ -d /home/$OPTARG.static ];
	then
		echo none /home/$OPTARG aufs br=/home/$OPTARG.dynamic=rw:/home/$OPTARG.static=ro:/home/$OPTARG=ro 0 0 >> /etc/fstab
		echo $"User account $OPTARG is now 'frozen'. Reboot this computer and log in as $OPTARG to not make any permanent changes."
		echo ""
		echo "If you wish to put temporary files and/or folders in the static directory, do so now by putting them in /home/$OPTARG.static."
		echo ""
		echo $"If you would like to 'freeze' other directories or users, you may do so."
	else
		echo none /home/$OPTARG aufs br=/home/$OPTARG.dynamic=rw:/home/$OPTARG=ro 0 0 >> /etc/fstab
		echo "User account $OPTARG is now 'frozen'. Reboot this computer and log in as $OPTARG to not make any permanent changes."
		echo ""
		echo "If you would like to 'freeze' other directories or users, you may do so."
fi
checkcmdline
}

prep() { # This prepares a user account for freezing.
ifroot
if [ ! -d /home/$OPTARG.dynamic ];
	then
		echo $"Making dynamic directory at /home/$OPTARG.dynamic for temporary files..."
		echo ""
		mkdir /home/$OPTARG.dynamic
		chown $OPTARG /home/$OPTARG.dynamic
fi
if [ ! -d /home/$OPTARG.static ];
	then
		echo $"Would you like to create a directory for read-only files"
		echo -n $"to be laid over the user directory at /home/$OPTARG.static? [Y/n]: "
		read STATYES
		echo ""
	else
		echo $"Static directory already created. Continuing..."
		echo ""
fi
if [ "$STATYES" = "Y" -o "$STATYES" = "y" ];
	then
		mkdir /home/$OPTARG.static
		chown  $OPTARG /home/$OPTARG.static
		STATNO=Y
fi
echo /home/$OPTARG >> $LISTNAME
echo $"Preparations complete!"
echo ""
}

unfreeze() { # This unfreezes all user accounts and directories that are frozen.
ifroot
if [ -f /tmp/.linreboot ];
	then
		echo $"There are users and/or directories waiting to be un-frozen."
		echo $"Please reboot this computer and execute $PROGNAME -c"
		echo ""
fi
if [ -f /etc/fstab.thaw ];
	then
		echo -n $"Would you like to 'unfreeze' all user accounts and directories? [Y/n]: "
		read UNFREEZE
		echo ""
	else
		echo $"There are no 'frozen' users or directories." 
		echo $"Freeze them with $PROGNAME [-f user] [-d directory]."
		exit 1
fi
if [ "$UNFREEZE" = "Y" -o "$UNFREEZE" = "y" ];
	then
		rm /etc/fstab
		mv /etc/fstab.thaw /etc/fstab
	else
		echo $"Leaving system as-is."
		exit 0
fi
checkfiles
echo $"All user accounts and/or directories have been 'unfrozen'."
echo ""
echo $"First reboot your computer for the temporary 'dynamic' directories to be safely unmounted."
echo ""
echo $"Then run $PROGNAME -c after rebooting to remove the temporary directories."
echo ""
echo $"If you put any files in a 'static' directory, you may wish to move them elsewhere now."
echo ""
echo $"To remove the 'static' directories, if any, use $PROGNAME -c [user or directory] after rebooting."
touch /tmp/.linreboot
if [ -f $LISTNAME ];
	then
		rm $LISTNAME
fi
}

specific() { # Unfreezes a specific user or directory
ifroot
SPEC=`echo "$OPTARG" | sed -e "s/\/*$//" ` # Removes the trailing slash of $OPTARG
if [ ! -f /etc/fstab.thaw ];
	then
		echo $"There are no users or directories 'frozen'. Exiting..."
		exit 0
fi
echo -n $"Would you like to 'unfreeze' $SPEC? [Y/n]: "
read SPECYES
if [ "$SPECYES" != "Y" -a "$SPECYES" != "y" ];
	then
		echo "Exiting..."
		exit 0
fi
if [ ! -f $SPECNAME ];
	then
		touch $SPECNAME
fi
if [ -d /home/$SPEC.dynamic ];
	then
		sed -i '\:/home/'$SPEC': d' /etc/fstab
		echo "/home/$SPEC.dynamic" >> $SPECDNAME
		touch /tmp/.linreboot
		echo $"User $SPEC has been 'unfrozen'."
		echo "First reboot your computer for the temporary 'dynamic' directories to be safely unmounted."
		echo ""
		echo "Then run $PROGNAME -c after rebooting to remove the temporary directories."
fi
if [ -d /home/$SPEC.static ];
	then
		touch /tmp/.linreboot
		echo "/home/$SPEC.static" >> $SPECSNAME
		echo ""
		echo "If you put any files in a 'static' directory, you may wish to move them elsewhere now."
		echo ""
		echo $"To remove the 'static' directory, use $PROGNAME -c after rebooting."
fi
if [ -d $SPEC.dynamic ];
	then
		sed -i '\:'$SPEC': d' /etc/fstab
		echo "$SPEC.dynamic" >> $SPECDNAME
		touch /tmp/.linreboot
		echo ""
		echo $"Directory $SPEC has been 'unfrozen'."
		echo "First reboot your computer for the temporary 'dynamic' directories to be safely unmounted."
		echo ""
		echo "Then run $PROGNAME -c after rebooting to remove the temporary directories."
		echo ""
fi
if [ -d $SPEC.static ];
	then
		touch /tmp/.linreboot
		echo "$SPEC.static" >> $SPECSNAME
		echo ""
		echo "If you put any files in a 'static' directory, you may wish to move them elsewhere now."
		echo ""
		echo "To remove the 'static' directory, use $PROGNAME -c after rebooting."
fi
if [ ! -d "/home/$SPEC.dynamic" -a ! -d "$SPEC.dynamic" ];
	then
		echo $"User or directory $SPEC is not frozen or does not exist. Exiting..."
		exit 1
fi
}

clean() { # Removes dynamic and static directories for unfrozen users and directories.
ifroot
checkfiles
if [ -f /tmp/.linreboot ];
	then
		echo $"This system needs to be rebooted before this function can be used."
		exit 1
fi
if [ -f "$SPECDNAME" -a -f "/etc/fstab.thaw" ];
	then
		echo -n $"Remove temporary directories for 'unfrozen' users/directories? [Y/n]: "
		read SPECDYN
		echo ""
	else
		SPECDYN=N
fi
if [ "$SPECDYN" = "Y" -o "$SPECDYN" = "y" ];
	then
		while read SPECDYNDIR; do
		rm -rf $SPECDYNDIR
		echo $"Removed $SPECDYNDIR"
		done < $SPECDNAME
		rm $SPECDNAME
fi
if [ -f "$SPECSNAME" -a -f "/etc/fstab.thaw" ];
	then
		echo $"Remove 'static directories for 'unfrozen' users/directories?"
		echo $"If you have files in any static directories, move them elsewhere."
		echo -n "[Y/n]: "
		read SPECSTAT
		echo ""
	else
		SPECSTAT=N
fi
if [ "$SPECSTAT" = "Y" -o "$SPECSTAT" = "y" ];
	then
		while read SPECSTATDIR; do
		rm -rf $SPECSTATDIR
		echo $"Removed $SPECSTATDIR"
		done < $SPECSNAME
		rm $SPECSNAME
fi
if [ ! -f /etc/fstab.thaw ];
	then
		echo -n $"Remove temporary directories for all users and folders? [Y/n]: "
		read REMDYN
		echo ""
	else
		REMDYN=N
fi
if [ "$REMDYN" = "Y" -o "$REMDYN" = "y" ];
	then
		rm -rf /home/*.dynamic
		echo $"'Dynamic' directories for users removed."
		DIRZ=Y
	else
		DIRZ=N
fi
if [ "$DIRZ" = "Y" -a -f "$FROZNAME" ];
	then
		while read FROZDIR; do
		rm -rf $FROZDIR
		echo $"Removed $FROZDIR"
		done < $FROZNAME
		rm $FROZNAME
fi
if [ ! -f /etc/fstab.thaw ];
	then
		echo -n $"Remove 'static' directories for all users? [Y/n]: "
		read HERP
		echo ""
	else
		HERP=N
fi
if [ "$HERP" = "Y" -o "$HERP" = "y" ];
	then
		rm -rf /home/*.static
		echo $"'Static' directories for users removed."
		echo ""
fi
if [ -f $STATNAME ];
	then
		echo -n $"Remove 'static' directories for all directories? [Y/n]: "
		read LAWL
		echo ""
	else
		LAWL=N
fi
if [ "$LAWL" = "Y" -o "$LAWL" = y ];
	then
		while read STATDIR; do
		rm -rf $STATDIR
		echo $"Removed $STATDIR."
		done < $STATNAME
		rm $STATNAME
fi
if [ -f $SPECDNAME ];
	then
		rm $SPECDNAME
fi
if [ -f $SPECSNAME ];
	then
		rm $SPECSNAME
fi
echo $"Cleanup complete!"
}

listfrozen() { # Lists frozen users and directories.
if [ -f $LISTNAME ];
	then
		echo $"The following directories are 'frozen':"
		cat $LISTNAME
	else
		echo $"There appear to be no 'frozen' directories or users on this system."
		echo "Exiting..."
		exit 1
fi
}

# Parse arguments

while getopts hvd:f:us:cl OPT; do
    case "$OPT" in
	h)	usage;
		exit 0
		;;
	v)	echo $"$NAMEPROPER version $VERSION"
		exit 0
		;;
	d)	directory;
		exit 0
		;;
	f)	user;
		exit 0	
		;;
	u)	unfreeze;
		exit 0
		;;
	s)	specific;
		exit 0
		;;
	c)	clean;
		exit 0
		;;
	l)	listfrozen;
		exit 0
		;;
	*)	usage;
		exit 1
		;;
    esac
done
if [ $# -le 1 ]; then
       usage;
       exit 0;
fi