cadmus_core/task/
dbus_monitor.rs

1//! D-Bus system bus monitor for debugging.
2//!
3//! Subscribes to all signals on the system bus and debug-logs every event.
4//! This is a diagnostic tool for investigating dhcpcd-dbus and
5//! wpa_supplicant interactions on Kobo devices (CAD-18).
6
7use std::sync::mpsc::Sender;
8use std::time::Duration;
9
10use futures_util::stream::StreamExt;
11
12use crate::task::{BackgroundTask, ShutdownSignal, TaskId};
13use crate::view::Event;
14
15const SHUTDOWN_POLL_INTERVAL: Duration = Duration::from_millis(200);
16
17/// Monitors the system D-Bus and logs all signal events.
18///
19/// Connects to the system bus via zbus, subscribes to every signal,
20/// and emits a `tracing::debug!` for each one. Intended as a
21/// development/diagnostic aid — only compiled when both `test` and
22/// `kobo` features are enabled.
23pub struct DbusMonitorTask;
24
25impl BackgroundTask for DbusMonitorTask {
26    fn id(&self) -> TaskId {
27        TaskId::DbusMonitor
28    }
29
30    fn run(&mut self, _hub: &Sender<Event>, shutdown: &ShutdownSignal) {
31        let rt = match tokio::runtime::Runtime::new() {
32            Ok(rt) => rt,
33            Err(e) => {
34                tracing::error!(error = %e, "failed to create tokio runtime");
35                return;
36            }
37        };
38
39        rt.block_on(async {
40            if let Err(e) = monitor(shutdown).await {
41                tracing::error!(error = %e, "dbus monitor exited with error");
42            }
43        });
44    }
45}
46
47async fn monitor(shutdown: &ShutdownSignal) -> Result<(), Box<dyn std::error::Error>> {
48    let connection = zbus::Connection::system().await?;
49    tracing::info!("connected to system bus");
50
51    let rule = zbus::MatchRule::builder()
52        .msg_type(zbus::message::Type::Signal)
53        .build();
54
55    let mut stream = zbus::MessageStream::for_match_rule(rule, &connection, Some(100)).await?;
56
57    tracing::info!("subscribed to all signals");
58
59    loop {
60        tokio::select! {
61            biased;
62
63            _ = async {
64                loop {
65                    if shutdown.should_stop() {
66                        return;
67                    }
68                    tokio::time::sleep(SHUTDOWN_POLL_INTERVAL).await;
69                }
70            } => {
71                tracing::info!("shutdown requested");
72                break;
73            }
74
75            msg = stream.next() => {
76                let Some(msg) = msg else { break };
77                let msg = match msg {
78                    Ok(m) => m,
79                    Err(e) => {
80                        tracing::warn!(error = %e, "failed to read dbus message");
81                        continue;
82                    }
83                };
84
85                let body = msg.body();
86                let body: Option<zbus::zvariant::Structure> = match body.deserialize() {
87                    Ok(b) => Some(b),
88                    Err(e) => {
89                        tracing::warn!(error = %e, "failed to deserialize dbus message body");
90                        None
91                    }
92                };
93
94                let header = msg.header();
95                tracing::debug!(
96                    dbus_message = ?msg,
97                    dbus_sender = ?header.sender(),
98                    dbus_path = ?header.path(),
99                    dbus_interface = ?header.interface(),
100                    dbus_member = ?header.member(),
101                    dbus_body = ?body,
102
103                    "dbus signal"
104                );
105            }
106        }
107    }
108
109    tracing::info!("dbus monitor stopped");
110    Ok(())
111}
cadmus_core/task/dbus_monitor.rs

cadmus_core/task/
dbus_monitor.rs
