Basic GUI to backup a Persistent Storage to another one

David A. Wheeler wrote a script that essentially wraps our command line instructions with a zenity GUI: see "[Tails-dev] Add simple GUI to back up persistent volume".

This can be useful if we can cheaply integrate this script into Tails, sufficiently earlier than the time we implement our preferred solution (#7049 (closed)).

Tasks

• Test in a running Tails
• Improve UI and strings if needed
• Improve the code if needed
• Integrate the script and launcher into Tails

==== tails-backup.desktop ====
[Desktop Entry]
Type=Application
Name=Backup persistent volume
Comment=Backup the Tails persistent volume to another TailsData volume
Exec=gnome-/usr/bin/gnome-terminal --title 'Log for Backing up Tails persistent volume' --hide-menubar -- /home/amnesia/Persistent/tails-backup
Terminal=false
Categories=Utilities
StartupNotify=false
#
# Test with:
# xdg-desktop-menu install tails-backup.desktop


==== tails-backup ====
#!/bin/sh
# tails-backup: Back up Tails' persistent disk into the mounted backup region.
# Persistent storage & backup storage must already be unlocked, and
# there must be an admin password set

set -eu

export TEXTDOMAIN='tails'

SOURCE='/live/persistence/TailsData_unlocked/'
DEST='/media/amnesia/TailsData/'
LOG="$HOME/backup-log.txt"

# Newline
NL="$(printf '\nX')"
NL="${NL%X}"

if [ ! -d "$SOURCE" ]; then
        msg="$(gettext -s 'Encrypted persistent storage must be unlocked first.  Please reboot, then unlock encrypted persistent storage and under additional settings set an administrative password.')"
        zenity --error --ellipsize --text "$msg"
        exit 1
fi

if [ ! -d "$DEST" ]; then
        msg="$(gettext -s 'Backup storage area must be unlocked first. Please run Applications ▸ Accessories ▸ Files, select the backup encrypted volume (TailsData), and unlock it with your passphrase.')"
        zenity --error --ellipsize --text "$msg"
        exit 1
fi

title="$(gettext -s 'Alert')"
msg="$(gettext -s 'Would you like to back up your persistent encrypted storage to the backup storage area? This will replace all data in the backup storage area.'"$NL"'If you agree, you will then need to enter your administrator password to actually run the backup.')"
if ! zenity --question --ellipsize --title "$title" --text "$msg"; then
        exit 1
fi

# Run real backup command. This requires privileges.
if pkexec /usr/bin/rsync -PaSHAXv --del "$SOURCE" "$DEST" ; then
        # Ensure RAM buffers are written out
        sync; sync; sync
        sleep 1
        msg="$(gettext -s 'Backup succeeded. Please eject (unmount) the backup storage area media.'"$NL"'You can do this by running Applications ▸ Accessories ▸ Files, selecting the backup encrypted volume (TailsData), and ejecting it.')"
        zenity --info --ellipsize --text "$msg"
        rm -fr "${LOG}"
else
        msg="$(gettext -s "Backup failed. See details in log file ${LOG}")"
        zenity --error --ellipsize --text "$msg"
        exit 1
fi