mirror/docs/kiosk-silverblue/check-kiosk.sh

#!/bin/sh
# check-kiosk.sh — read-only report on a mirror kiosk client. Run ON THE CLIENT.
#
#   sudo sh check-kiosk.sh
#
# PASS/FAIL describe this machine; WARN means "configured fine, but the thing
# you can see on the screen will still be wrong". Exits non-zero on FAIL.
#
# Nothing here needs the console: every check is readable over SSH, which is
# the whole point of a kiosk you never plug a keyboard into.

KIOSK_USER="${KIOSK_USER:-kiosk}"
FAILS=0

ok() { printf 'PASS  %s\n' "$*"; }
bad() { printf 'FAIL  %s\n' "$*"; FAILS=$((FAILS + 1)); }
warn() { printf 'WARN  %s\n' "$*"; }
info() { printf 'info  %s\n' "$*"; }

SUDO=""
[ "$(id -u)" -eq 0 ] || SUDO="sudo"

printf '%s\n' '--- machine ---'
if [ -f /etc/os-release ]; then
    info "$( . /etc/os-release && printf '%s %s' "$NAME" "$VERSION_ID" ) on $(uname -m)"
fi
if command -v rpm-ostree >/dev/null 2>&1; then
    info "booted deployment: $(rpm-ostree status 2>/dev/null | sed -n 's/^ *● *//p' | head -1)"
    info "layered: $(rpm-ostree status 2>/dev/null | sed -n 's/^ *LayeredPackages: //p' | head -1)"
fi

printf '\n%s\n' '--- packages ---'
for p in gnome-kiosk gnome-kiosk-script-session firefox; do
    if rpm -q "$p" >/dev/null 2>&1; then ok "$p installed"; else bad "$p not installed (rpm-ostree install $p)"; fi
done

printf '\n%s\n' '--- user ---'
if id -u "$KIOSK_USER" >/dev/null 2>&1; then
    HOME_DIR=$(getent passwd "$KIOSK_USER" | cut -d: -f6)
    ok "user $KIOSK_USER exists, home $HOME_DIR"
else
    bad "user $KIOSK_USER does not exist"
    HOME_DIR=""
fi

printf '\n%s\n' '--- payload ---'
check_file() {
    path=$1 needle=$2 label=$3
    if [ -f "$path" ]; then
        if [ -n "$needle" ] && ! $SUDO grep -q "$needle" "$path" 2>/dev/null; then
            bad "$label: $path exists but has no '$needle'"
        else
            ok "$label: $path"
        fi
    else
        bad "$label: $path is missing"
    fi
}
URL=""
if [ -n "$HOME_DIR" ]; then
    check_file "$HOME_DIR/.local/bin/gnome-kiosk-script" "firefox --kiosk" "kiosk script"
    if [ -f "$HOME_DIR/.config/mirror/kiosk.conf" ]; then
        URL=$($SUDO sed -n 's/^MIRROR_KIOSK_URL="\{0,1\}\([^"]*\)"\{0,1\}$/\1/p' \
              "$HOME_DIR/.config/mirror/kiosk.conf" 2>/dev/null | head -1)
        ok "kiosk URL: ${URL:-<empty>}"
        case "$URL" in
            */watch|*/kiosk) : ;;
            "") bad "kiosk URL is empty" ;;
            *) warn "kiosk URL is neither wall (/watch or /kiosk): $URL — check DNS and the nginx vhost" ;;
        esac
    else
        bad "kiosk config $HOME_DIR/.config/mirror/kiosk.conf is missing"
    fi
    check_file "$HOME_DIR/.config/gnome-initial-setup-done" "" "initial-setup guard"
fi
check_file /etc/firefox/policies/policies.json "DisableAppUpdate" "firefox policy"
check_file /usr/local/share/gnome-kiosk/window-config.ini "org.mozilla" "kiosk window rules"
# Without this key the shipped gnome-kiosk session never registers with GDM and
# GDM autospawns a greeter over the wall ~8s after auto-login. The single most
# confusing failure this setup has: the kiosk keeps running underneath, so the
# mirror roster and loginctl both still look perfect while the screen shows a
# login prompt.
check_file /usr/local/share/wayland-sessions/gnome-kiosk-script-wayland.desktop \
    "X-GDM-SessionRegisters=true" "GDM session override"

printf '\n%s\n' '--- session wiring ---'
ACCT="/var/lib/AccountsService/users/$KIOSK_USER"
if [ -f "$ACCT" ] && $SUDO grep -q '^Session=gnome-kiosk-script-wayland' "$ACCT"; then
    ok "AccountsService default session is the kiosk"
else
    bad "AccountsService session for $KIOSK_USER is not gnome-kiosk-script-wayland"
    [ -f "$ACCT" ] && info "$($SUDO cat "$ACCT" 2>/dev/null | tr '\n' ' ')"
fi
if [ -f /etc/gdm/custom.conf ] &&
   $SUDO grep -qi "^AutomaticLogin=$KIOSK_USER\$" /etc/gdm/custom.conf &&
   $SUDO grep -qi "^AutomaticLoginEnable=True" /etc/gdm/custom.conf; then
    ok "gdm auto-login targets $KIOSK_USER"
else
    bad "gdm auto-login is not enabled for $KIOSK_USER"
fi

printf '\n%s\n' '--- running state ---'
SEAT_USER=$(loginctl list-sessions --no-legend 2>/dev/null | awk '$4=="seat0"{print $3; exit}')
if [ -z "$SEAT_USER" ]; then
    warn "nobody is logged in on seat0 (sudo systemctl restart gdm)"
elif [ "$SEAT_USER" = "$KIOSK_USER" ]; then
    ok "seat0 is logged in as $KIOSK_USER"
else
    bad "seat0 is logged in as '$SEAT_USER', not $KIOSK_USER (sudo systemctl restart gdm)"
fi
SEAT_SESSION=$(loginctl list-sessions --no-legend 2>/dev/null | awk '$4=="seat0"{print $1; exit}')
if [ -n "$SEAT_SESSION" ]; then
    info "seat0 session $SEAT_SESSION: class=$(loginctl show-session "$SEAT_SESSION" -p Class --value 2>/dev/null) type=$(loginctl show-session "$SEAT_SESSION" -p Type --value 2>/dev/null)"
fi

# Does the kiosk actually hold the screen? A session can be Active while another
# one owns the foreground VT, which is what a covered wall looks like from here.
KIOSK_SESSION=$(loginctl list-sessions --no-legend 2>/dev/null |
    awk -v u="$KIOSK_USER" '$3==u && $4=="seat0"{print $1; exit}')
if [ -n "$KIOSK_SESSION" ]; then
    K_ACTIVE=$(loginctl show-session "$KIOSK_SESSION" -p Active --value 2>/dev/null)
    K_TTY=$(loginctl show-session "$KIOSK_SESSION" -p TTY --value 2>/dev/null)
    K_FG=$(sudo cat /sys/class/tty/tty0/active 2>/dev/null)
    if [ "$K_ACTIVE" = "yes" ] && [ -n "$K_TTY" ] && [ "$K_FG" = "$K_TTY" ]; then
        ok "the kiosk holds the console (foreground VT $K_FG)"
    else
        bad "console is on ${K_FG:-?} but the kiosk is on ${K_TTY:-?} (Active=$K_ACTIVE) — the screen is showing something else"
        info "fix: sudo loginctl activate $KIOSK_SESSION, then check the session override above"
    fi
fi

# Count the greeter *sessions* GDM created this boot, not every mention: a
# healthy kiosk creates none, and the autospawn bug creates exactly one soon
# after auto-login. (journalctl has no --no-legend; using it here once made this
# test read an empty stream and pass unconditionally — a silent false green.)
GREETERS=$(sudo journalctl -b --no-pager 2>/dev/null |
    grep -c "New session .* of user 'gdm-greeter'")
if [ "${GREETERS:-0}" -gt 0 ]; then
    warn "$GREETERS GDM greeter session(s) this boot: the wall may be covered by a login screen"
    info "check X-GDM-SessionRegisters=true in /usr/local/share/wayland-sessions/"
fi

if [ -n "$HOME_DIR" ]; then
    KUID=$(id -u "$KIOSK_USER")
    FF=$(pgrep -u "$KUID" -a firefox 2>/dev/null | head -1)
    if [ -z "$FF" ]; then
        warn "no firefox running as $KIOSK_USER yet"
    else
        case "$FF" in
            *--kiosk*) ok "$FF" ;;
            *) warn "firefox is running without --kiosk: $FF" ;;
        esac
    fi
    if [ -f "$HOME_DIR/.local/state/mirror-kiosk.log" ]; then
        info "last kiosk log lines:"
        $SUDO tail -5 "$HOME_DIR/.local/state/mirror-kiosk.log" 2>/dev/null | sed 's/^/       /'
    fi
fi

printf '\n%s\n' '--- hang recovery ---'
# An unattended wall has to end a hang with a reboot, not with a frozen frame for
# a week. Two independent layers; ../kiosk-silverblue.md ("When the wall hangs").
sc() { sysctl -n "$1" 2>/dev/null || echo missing; }
for k in kernel.softlockup_panic kernel.hardlockup_panic kernel.panic_on_oops; do
    v=$(sc "$k")
    case "$v" in
        1) ok "$k = 1" ;;
        missing) warn "$k does not exist in this kernel build"
                 warn "  (kernel.hung_task_panic is absent from Fedora's kernel; the watchdog covers it)" ;;
        *) bad "$k = $v, expected 1 — fix /etc/sysctl.d/90-mirror-wall-selfheal.conf, then sudo sysctl --system" ;;
    esac
done
P=$(sc kernel.panic)
case "$P" in
    ''|0|missing) bad "kernel.panic = ${P:-unset}: after a panic the box sits there forever" ;;
    *) ok "kernel.panic = $P (reboots $P s after a panic)" ;;
esac
if [ -e /dev/watchdog ]; then
    WD=$(systemctl show -p RuntimeWatchdogUSec --value 2>/dev/null || echo 0)
    WID=$(cat /sys/class/watchdog/watchdog0/identity 2>/dev/null || echo '?')
    case "$WD" in
        0|''|infinity) bad "PID 1 is not kicking the $WID watchdog (RuntimeWatchdogUSec=$WD) — a wedged kernel here never recovers" ;;
        *) ok "hardware watchdog armed: $WID at $WD (no kick from PID 1 for $WD = chipset reset)" ;;
    esac
else
    info "no /dev/watchdog on this box — the lockup panics are the only recovery layer"
fi

printf '\n%s\n' '--- firewall ---'
if command -v firewall-cmd >/dev/null 2>&1 && firewall-cmd --state >/dev/null 2>&1; then
    ZONE=$(firewall-cmd --get-default-zone)
    PORTS=$(firewall-cmd --zone="$ZONE" --list-ports | tr ' ' '\n')
    if printf '%s\n' "$PORTS" | grep -qx '1025-65535/tcp'; then
        bad "$ZONE opens 1025-65535/tcp — on a box whose only access control is its address, that is every high port"
    else
        ok "$ZONE: 1025-65535/tcp closed"
    fi
    if printf '%s\n' "$PORTS" | grep -qx '1025-65535/udp'; then
        ok "$ZONE: 1025-65535/udp open (WebRTC media needs it — do not close it)"
    else
        bad "$ZONE: 1025-65535/udp closed — peer-to-peer media cannot flow, every tile reads 'unreachable'"
    fi
else
    info "firewalld is not running — nothing listening, nothing to tighten"
fi

printf '\n%s\n' '--- what the screen will show ---'
if [ -n "$URL" ]; then
    BODY=$(curl -fsSL -m 8 "$URL" 2>/dev/null)
    if [ -z "$BODY" ]; then
        warn "$URL is not reachable from this machine right now"
    else
        CODE=$(curl -s -o /dev/null -w '%{http_code}' -m 8 "$URL" 2>/dev/null)
        if printf '%s' "$BODY" | grep -q "Watch · mirror"; then
            ok "$URL serves the mirror watch page (HTTP $CODE)"
        elif printf '%s' "$BODY" | grep -q "Wall · mirror"; then
            ok "$URL serves the mirror kiosk page (HTTP $CODE)"
        else
            warn "$URL answered HTTP $CODE but it is NOT a mirror wall — the kiosk"
            warn "will happily display whatever this is. Check DNS and the nginx vhost."
            info "title: $(printf '%s' "$BODY" | sed -n 's/.*<title>\(.*\)<\/title>.*/\1/p' | head -1)"
        fi
    fi
else
    info "no URL configured, nothing to fetch"
fi

printf '\n'
if [ "$FAILS" -gt 0 ]; then
    printf '%s check(s) FAILED.\n' "$FAILS"
    exit 1
fi
printf 'All checks passed.\n'