#!/system/bin/sh
set -eu

readonly RPC_HOST="127.0.0.1"
readonly RPC_PORT="8444"
readonly RPC_TIMEOUT_SEC="60"
readonly POLL_INTERVAL_SEC="15"
readonly NODE_NAME="montana-node"

probe_rpc() {
    /system/bin/timeout "$RPC_TIMEOUT_SEC" /system/bin/nc -z "$RPC_HOST" "$RPC_PORT"
}

check_dumpable_off() {
    local pid
    pid="$(pidof "$NODE_NAME" || true)"
    [ -z "$pid" ] && return 0
    local dumpable
    dumpable="$(awk '/^Dumpable:/ {print $2}' "/proc/$pid/status" 2>/dev/null || echo 1)"
    [ "$dumpable" = "0" ]
}

check_locked_pages() {
    local pid
    pid="$(pidof "$NODE_NAME" || true)"
    [ -z "$pid" ] && return 0
    local locked_kb
    locked_kb="$(awk '/^VmLck:/ {print $2}' "/proc/$pid/status" 2>/dev/null || echo 0)"
    [ "$locked_kb" -gt 0 ]
}

while :; do
    if ! probe_rpc; then
        log -p w -t montana-watchdog "RPC unreachable on $RPC_HOST:$RPC_PORT, restarting $NODE_NAME"
        setprop ctl.restart "$NODE_NAME"
        sleep "$RPC_TIMEOUT_SEC"
    elif ! check_dumpable_off; then
        log -p e -t montana-watchdog "BLOCKING: $NODE_NAME PR_SET_DUMPABLE not zero, stopping node"
        setprop ctl.stop "$NODE_NAME"
        sleep "$RPC_TIMEOUT_SEC"
    elif ! check_locked_pages; then
        log -p e -t montana-watchdog "BLOCKING: $NODE_NAME has no locked pages, stopping node"
        setprop ctl.stop "$NODE_NAME"
        sleep "$RPC_TIMEOUT_SEC"
    fi
    sleep "$POLL_INTERVAL_SEC"
done