implement reload command

src/main.rs

@@ -1,18 +1,23 @@
-use std::path::{PathBuf};
-use clap::{Parser, Subcommand};
-use main_error::MainResult;
 use crate::config::{Config, ForwardSource, ForwardTarget, NamespaceName};
 use crate::daemon::daemon;
 use crate::down::down;
 use crate::proxy::proxy;
 use crate::up::up;
+use clap::{Parser, Subcommand};
+use main_error::MainResult;
+use std::path::PathBuf;
+use nix::errno::Errno;
+use nix::sys::signal::{kill, Signal};
+use nix::unistd::Pid;
+use sysinfo::{ProcessRefreshKind, RefreshKind, System, UpdateKind};
+use tracing::{error, info, warn};
 
 mod config;
 mod daemon;
+mod down;
+mod link;
 mod namespace;
 mod proxy;
-mod link;
-mod down;
 mod up;
 
 #[derive(Parser, Debug)]
@@ -55,26 +60,54 @@ enum Commands {
 fn main() -> MainResult {
     let args: Args = Args::parse();
     tracing_subscriber::fmt::init();
-    
+
     match args.command {
         Commands::Daemon { config } => {
             let config = Config::load(config)?;
             daemon(config)
         }
-        Commands::Up {config} => {
+        Commands::Up { config } => {
             let config = Config::load(config)?;
             up(config)
         }
-        Commands::Down => {
-            down()
-        }
+        Commands::Down => down(),
         Commands::Reload => reload(),
-        Commands::Proxy {source, target, source_namespace, target_namespace} => {
-            proxy(source_namespace, target_namespace, source, target)
-        },
+        Commands::Proxy {
+            source,
+            target,
+            source_namespace,
+            target_namespace,
+        } => proxy(source_namespace, target_namespace, source, target),
     }
 }
 
 fn reload() -> MainResult {
-    todo!()
-}
+    let s = System::new_with_specifics(
+        RefreshKind::default()
+            .with_processes(ProcessRefreshKind::default().with_cmd(UpdateKind::OnlyIfNotSet)),
+    );
+
+    let mut found = false;
+    for proc in s.processes_by_exact_name("netnsd".as_ref()) {
+        if proc.cmd().get(1).and_then(|s| s.to_str()) == Some("daemon") {
+            found = true;
+            match kill(Pid::from_raw(proc.pid().as_u32() as i32), Signal::SIGHUP) {
+                Ok(_) => {
+                    info!("Sent reload command to daemon")
+                },
+                Err(Errno::EPERM) => {
+                    error!("Sending signal not permitted, try are you running the command as root?");
+                },
+                Err(error) => {
+                    error!(%error, "Unexpected error");
+                }
+            }
+        }
+    }
+
+    if !found {
+        warn!("No daemon process found")
+    }
+
+    Ok(())
+}