testsAndMisc/phone_focus_mode/README.md

Phone Focus Mode

Location-based app restriction for a rooted Android phone using wireless ADB.

When within ~500m of home: only whitelisted productive apps remain usable. When outside that radius: all apps work normally.

Requirements

• Rooted phone with Magisk installed
• Wireless ADB enabled (Settings → Developer options → Wireless debugging)
• adb installed on your PC (sudo apt install adb on Debian/Ubuntu)
• GPS/Location enabled on the phone

Setup (first time)

1. Find your home coordinates

Open Google Maps, right-click your apartment → copy the coordinates shown.

2. Edit config_secrets.sh

HOME_LAT="-48.876667"   # your latitude
HOME_LON="-123.393333"  # your longitude

3. (Optional) Adjust the whitelist in config.sh

To find the exact package name of any app:

./deploy.sh <phone_ip> --find-pkg stronglift
./deploy.sh <phone_ip> --find-pkg anki
./deploy.sh <phone_ip> --find-pkg pomodoro

Then add the correct package name to WHITELIST in config.sh.

4. Deploy

chmod +x deploy.sh
./deploy.sh 192.168.1.42        # replace with your phone's IP

This:

1. Pushes all scripts to /data/local/tmp/focus_mode/ on the device
2. Installs a Magisk service.d script so the daemon auto-starts on boot
3. Starts the daemon immediately

Usage

./deploy.sh <ip> --status    # Current mode, location, distance from home
./deploy.sh <ip> --log       # View recent daemon log
./deploy.sh <ip> --list      # List all apps + whitelist status
./deploy.sh <ip> --enable    # Force focus mode ON (for testing)
./deploy.sh <ip> --disable   # Force focus mode OFF
./deploy.sh <ip> --stop      # Stop daemon entirely (restores all apps)
./deploy.sh <ip> --start     # Start daemon
./deploy.sh <ip> --restart   # Restart daemon (picks up config changes)
./deploy.sh <ip> --pull-log  # Download log file to your PC

How it works

Every 60 seconds:
  get_location()  ─── dumpsys location ──► lat,lon
        │
        ▼
  calc_distance()  ─── Haversine formula ──► meters
        │
        ├── within radius?  ──► enable_focus_mode()
        │                           pm disable-user all non-whitelisted apps
        │                           record which apps were disabled
        │
        └── outside radius? ──► disable_focus_mode()
                                    pm enable each app in the disabled list

Hysteresis: 50m buffer prevents rapid toggling at the boundary. You must travel radius - 50m inward to trigger lock, and radius + 50m outward to unlock.

Fail-safe: If location is unavailable for 5 consecutive checks (~5 minutes), focus mode is automatically disabled so you can't be locked out.

State persistence: The daemon records exactly which apps it disabled (in /data/local/tmp/focus_mode/disabled_by_focus.txt), so it never accidentally re-enables apps that were already disabled by the user before focus mode ran.

On-device control (without PC)

From a root terminal app (e.g. Termux + tsu):

su --mount-master -c 'sh /data/local/tmp/focus_mode/focus_ctl.sh status'
su --mount-master -c 'sh /data/local/tmp/focus_mode/focus_ctl.sh disable'

Why --mount-master: MagiskSU puts each su -c session in an isolated mount namespace by default, so bind mounts made by the hosts enforcer would be invisible (and /data/adb/focus_mode/* checks would fail due to SELinux interactions). --mount-master joins the global namespace where the daemons (started from Magisk service.d at boot) actually live. The boot autostart script doesn't need this flag because post-fs-data already runs there.

File layout

File	Purpose
config.sh	Coordinates, radius, whitelist, constants
focus_daemon.sh	Main daemon — runs on device, loops every 60s
focus_ctl.sh	Control utility — runs on device
curfew_enforcer.sh	Night-curfew enforcer — grayscale + DND + optional net
hosts_enforcer.sh	Bind-mounts hosts.canonical over /system/etc/hosts
magisk_service.sh	Magisk boot hook → auto-starts both daemons
deploy.sh	PC-side ADB deployment and control script

Hosts hardening

A second daemon, hosts_enforcer.sh, locks the phone's /system/etc/hosts to the same blocklist installed by linux_configuration/hosts/install.sh on the PC. Three layers:

1. Canonical copy at /data/adb/focus_mode/hosts.canonical is chattr +i.
2. It is bind-mounted read-only over /system/etc/hosts at boot.
3. A watchdog verifies a sha256 every 15 seconds and restores on mismatch.

This blocks the common echo > /etc/hosts one-liner from a terminal app. It is NOT a guarantee against a determined root user on the device itself — a real "impossible without USB" gate would require removing su access, which would break the rest of this system. The watchdog at least ensures tampering is logged and reverted within ~15s.

Status and logs:

./deploy.sh <ip> --hosts-status
./deploy.sh <ip> --hosts-log

Periodic rescan / Play Store

The focus daemon now re-scans every tick (not just on first entry). If you re-enable an app via Play Store or pm enable, it gets re-disabled within CHECK_INTERVAL_FOCUS seconds. com.android.vending (Play Store), com.*.packageinstaller, and popular terminal apps are also uninstalled --user 0 in focus mode to close the usual bypass paths. Google Play Services (com.google.android.gms) is left alone so banking apps work.

More detail

Split out to stay under the 250-line cap.

• Night curfew and the hotspot/tethering block
• Updating and troubleshooting