feat: Support syslog

Fixes #2.

Cargo.toml

@@ -4,6 +4,10 @@ version = "0.2.0"
 edition = "2021"
 description = "mini-udev workalike"
 
+[features]
+default = ["syslog"]
+syslog = ["dep:syslog-tracing"]
+
 [dependencies]
 anyhow = "1.0.95"
 bytes = "1.9.0"
@@ -14,6 +18,7 @@ kobject-uevent = "0.2.0"
 mdev-parser = "0.1.1"
 netlink-sys = { version = "0.8.7", features = ["tokio_socket"] }
 nix = { version = "0.29.0", features = ["user", "fs"] }
+syslog-tracing = { version = "0.3.1", optional = true }
 thiserror = "2.0.9"
 tokio = { version = "1.42.0", features = [
     "macros",

src/bin/mdev-coldplug.rs

@@ -17,15 +17,17 @@ struct Opt {
 }
 
 impl Opt {
-    fn setup_log(&self) -> anyhow::Result<()> {
-        setup_log(self.verbose)
+    fn setup_log(&self) {
+        use tracing_subscriber::{fmt, prelude::*};
+        let fmt_layer = fmt::layer().with_target(false);
+        setup_log(self.verbose).with(fmt_layer).init();
     }
 }
 
 fn main() -> anyhow::Result<()> {
     let opt = Opt::parse();
 
-    opt.setup_log()?;
+    opt.setup_log();
 
     let classdir = WalkDir::new(opt.sysfs_mount.join("class"))
         .follow_links(true)

src/bin/mdev.rs

@@ -1,6 +1,6 @@
 use std::{
     collections::HashMap,
-    ffi::OsStr,
+    ffi::{CString, OsStr},
     path::{Path, PathBuf},
 };
 
@@ -13,6 +13,7 @@ use nix::{
     sys::stat::{makedev, mknod, Mode, SFlag},
     unistd::{chown, unlink},
 };
+use syslog_tracing::Syslog;
 use tokio::{fs, join};
 use tracing::{debug, info, warn};
 use walkdir::WalkDir;
@@ -253,16 +254,36 @@ impl Opt {
         Ok(())
     }
 
-    fn setup_log(&self) -> anyhow::Result<()> {
+    fn setup_log(&self) {
+        use tracing_subscriber::{fmt, prelude::*};
         if self.daemon && !self.foreground && !self.syslog {
-            return Ok(());
+            return;
         }
 
+        let registry = setup_log(self.verbose);
+        let fmt_layer = fmt::layer().with_target(false);
+
         if self.syslog {
-            todo!("Wire in syslog somehow");
+            // SAFETY: They are strings that do not contain a null byte
+            let identity = std::env::args()
+                .next()
+                .map_or_else(|| CString::new("mdev"), |name| CString::new(name))
+                .unwrap();
+            let syslog = Syslog::new(
+                identity,
+                syslog_tracing::Options::LOG_PID,
+                syslog_tracing::Facility::Daemon,
+            )
+            .unwrap();
+            let fmt_layer = fmt_layer
+                .with_level(false)
+                .without_time()
+                .with_writer(syslog);
+
+            registry.with(fmt_layer).init();
+        } else {
+            registry.with(fmt_layer).init();
         }
-
-        setup_log(self.verbose)
     }
 }
 
@@ -283,7 +304,7 @@ fn main() -> anyhow::Result<()> {
 
     let opt = Opt::parse();
 
-    opt.setup_log()?;
+    opt.setup_log();
 
     if opt.scan {
         opt.run_scan(&conf)?;

src/lib.rs

@@ -10,6 +10,7 @@ use futures_util::ready;
 use kobject_uevent::UEvent;
 use netlink_sys::{AsyncSocket, SocketAddr, TokioSocket};
 use tokio::sync::mpsc;
+use tracing_subscriber::{layer::Layered, prelude::*, EnvFilter, Registry};
 
 pub mod rule;
 pub mod stream;
@@ -196,12 +197,7 @@ mod tests {
     }
 }
 
-pub fn setup_log(verbose: u8) -> anyhow::Result<()> {
-    use tracing_subscriber::prelude::*;
-    use tracing_subscriber::{fmt, EnvFilter};
-
-    let fmt_layer = fmt::layer().with_target(false);
-
+pub fn setup_log(verbose: u8) -> Layered<EnvFilter, Registry> {
     let filter_layer = EnvFilter::try_from_default_env().unwrap_or_else(|_| {
         if verbose < 1 {
             EnvFilter::new("info")
@@ -212,10 +208,5 @@ pub fn setup_log(verbose: u8) -> anyhow::Result<()> {
         }
     });
 
-    tracing_subscriber::registry()
-        .with(filter_layer)
-        .with(fmt_layer)
-        .init();
-
-    Ok(())
+    tracing_subscriber::registry().with(filter_layer)
 }