daemon starts in pwd (#640)

This is the default behavior when not daemonizing.

bin/common/daemonize/unix.rs

@@ -1,4 +1,4 @@
-use std::path::Path;
+use std::{env::current_dir, path::Path};
 
 use daemonize::Daemonize;
 use log::error;
@@ -8,7 +8,12 @@ use log::error;
 /// This function will redirect `stdout`, `stderr` to `/dev/null`,
 /// and follow the exact behavior in shadowsocks-libev
 pub fn daemonize<F: AsRef<Path>>(pid_path: Option<F>) {
-    let mut d = Daemonize::new().umask(0).chroot("/");
+    let pwd = current_dir()
+        .unwrap_or_else(|err| panic!("cannot get current working directory, {:?}", err))
+        .canonicalize()
+        .unwrap_or_else(|err| panic!("cannot get absolute path to working directory, {:?}", err));
+    let mut d = Daemonize::new().umask(0).working_directory(pwd);
+
     if let Some(p) = pid_path {
         d = d.pid_file(p);
     }