From db7d30d4c18e76eabdd2bb5dcd67c5121aec854b Mon Sep 17 00:00:00 2001
From: pyr0ball <pyroballpcs@gmail.com>
Date: Mon, 18 May 2026 17:13:36 -0700
Subject: [PATCH] =?UTF-8?q?feat(m1):=20kmsg=20watcher=20=E2=80=94=20reads?=
 =?UTF-8?q?=20/dev/kmsg=20kernel=20ring=20buffer?=
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---
 src-tauri/src/watcher/kmsg.rs | 65 +++++++++++++++++++++++++++++++++--
 1 file changed, 62 insertions(+), 3 deletions(-)

diff --git a/src-tauri/src/watcher/kmsg.rs b/src-tauri/src/watcher/kmsg.rs
index 3c2c47d..f3c524c 100644
--- a/src-tauri/src/watcher/kmsg.rs
+++ b/src-tauri/src/watcher/kmsg.rs
@@ -1,6 +1,65 @@
-use super::SystemEvent;
+use super::{EventSource, SystemEvent, now_unix};
+use tokio::fs::File;
+use tokio::io::{AsyncBufReadExt, BufReader};
 use tokio::sync::mpsc;
 
-pub async fn watch(_tx: mpsc::Sender<SystemEvent>) {
-    // implemented in Task 7
+pub async fn watch(tx: mpsc::Sender<SystemEvent>) {
+    let file = match File::open("/dev/kmsg").await {
+        Ok(f) => f,
+        Err(e) => {
+            log::warn!("kmsg watcher: cannot open /dev/kmsg: {e}");
+            return;
+        }
+    };
+
+    let mut lines = BufReader::new(file).lines();
+    while let Ok(Some(line)) = lines.next_line().await {
+        if let Some(msg) = parse_kmsg(&line) {
+            let _ = tx
+                .send(SystemEvent {
+                    source: EventSource::Kmsg,
+                    raw_line: msg,
+                    timestamp: now_unix(),
+                })
+                .await;
+        }
+    }
+}
+
+fn parse_kmsg(line: &str) -> Option<String> {
+    let msg = if let Some(pos) = line.find(';') {
+        &line[pos + 1..]
+    } else {
+        line
+    };
+    if msg.is_empty() {
+        return None;
+    }
+    Some(msg.to_string())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parses_kmsg_line_with_semicolon() {
+        let line = "6,1234,56789,-;usb 1-1: new full-speed USB device number 2";
+        assert_eq!(
+            parse_kmsg(line),
+            Some("usb 1-1: new full-speed USB device number 2".to_string())
+        );
+    }
+
+    #[test]
+    fn parses_kmsg_line_without_semicolon() {
+        let line = "plain message without header";
+        assert_eq!(parse_kmsg(line), Some("plain message without header".to_string()));
+    }
+
+    #[test]
+    fn skips_empty_message_after_semicolon() {
+        let line = "6,1234,56789,-;";
+        assert_eq!(parse_kmsg(line), None);
+    }
 }