Refactor PCIe device management logic to improve readability and error handling

src/main.rs

@@ -1,47 +1,56 @@
 #![feature(file_buffered)]
-#![feature(buf_read_has_data_left)]
-use regex::Regex;
 use std::fs::File;
 use std::io::BufRead;
-use std::io::prelude::*;
-use std::time::Duration;
+use std::io::Write;
 
 fn main() {
     println!("Reading kernel messages...");
 
-    let re = Regex::new(
-        r"(?P<priority>\d+),(?P<sequence>\d+),(?P<timestamp>\d+),-;igb (?P<id>\d{4}:\d{2}:\d{2}.\d).*: PCIe link lost"
-    ).unwrap();
-    let kmsg_file = File::open_buffered("/dev/kmsg").expect("Failed to open /dev/kmsg");
+    let kmsg_file =
+        File::open_buffered("/dev/kmsg").expect("Failed to open /dev/kmsg");
 
-    for line in kmsg_file.lines() {
-        if let Ok(line) = line {
-            let caps = re.captures(line.as_str());
-            if let Some(caps) = caps {
-                let timestamp = &caps["timestamp"];
-                let id = &caps["id"];
-                println!("Resetting {id}");
+    let lines = kmsg_file.lines();
+    for line in lines {
+        match line {
+            Err(e) => println!("Error reading line: {e}"),
+            Ok(line) => manage_line(line),
+        }
+    }
+}
 
-                let rm_file_path = format!("/sys/bus/pci/devices/{id}/remove");
-                let mut rm_file = File::create(&rm_file_path)
-                    .expect(format!("Failed to open remove file at {rm_file_path}").as_str());
-                rm_file
-                    .write_all(b"1")
-                    .expect("Failed to write to remove file");
-                println!("Removed device {id}");
+fn manage_line(line: String) {
+    if let Some((prefix, line)) = line.split_once(";") {
+        if line.ends_with("PCIe link lost") {
+            println!("PCIe link lost {prefix}");
 
-                let mut rescan_file =
-                    File::create("/sys/bus/pci/rescan").expect("Failed to open rescan file");
-                rescan_file
-                    .write_all(b"1")
-                    .expect("Failed to write to rescan file");
-                println!("Rescanned PCI bus");
-
-                let time = Duration::from_millis(
-                    timestamp.parse::<u64>().expect("Failed to parse timestamp"),
-                );
-                println!("Device {id} reset at {time:#?}");
+            let id = line.splitn(3, " ").nth(1);
+            if let Some(id) = id {
+                reset_device(id);
             }
         }
     }
 }
+
+fn reset_device(id: &str) {
+    println!("Resetting {id}");
+    echo1(rm_file_path(&id));
+    echo1(String::from("/sys/bus/pci/rescan"));
+    println!("Rescanned PCI bus");
+}
+
+fn echo1(path: String) {
+    let rm_file = File::create(&path);
+    match rm_file {
+        Err(e) => println!("Failed to open remove file at {path}: {e}"),
+        Ok(mut file) => {
+            file
+                .write_all(b"1")
+                .expect("Failed to write to remove file");
+            println!("Removed device {path}");
+        }
+    }
+}
+
+fn rm_file_path(id: &str) -> String {
+    format!("/sys/bus/pci/devices/{id}/remove")
+}