--- a/src/command.rs	Fri Oct 30 13:58:33 2020 +0900
+++ b/src/command.rs	Sun Nov 01 12:52:13 2020 +0900
@@ -11,7 +11,7 @@
 
 pub fn start_command(user_name: &'static str, vm_name: String) {
     let vm_name = match vm_name.parse::<u8>() {
-        Ok(_) => String::from(format!("{}-{}", user_name, vm_name)),
+        Ok(_) => format!("{}-{}", user_name, vm_name),
         Err(_) => vm_name,
     };
 

--- a/src/user.rs	Fri Oct 30 13:58:33 2020 +0900
+++ b/src/user.rs	Sun Nov 01 12:52:13 2020 +0900
@@ -1,40 +1,33 @@
-use nix;
-
 pub fn getlogin(uid: u32) -> &'static str {
     use std::ffi::CStr;
     let user_passwd = unsafe { nix::libc::getpwuid(uid) };
     let c_str = unsafe { CStr::from_ptr((*user_passwd).pw_name) };
-    return c_str.to_str().unwrap();
+    c_str.to_str().unwrap()
 }
 
 pub fn getuid() -> u32 {
     let uid_struct = nix::unistd::getuid();
-    return uid_struct.into();
+    uid_struct.into()
 }
 
 pub fn getgid() -> u32 {
     let gid_struct = nix::unistd::getgid();
-    return gid_struct.into();
+    gid_struct.into()
 }
 
+const ROOT_ID: u32 = 0;
+
 pub fn set_root_id() {
-    let id = 0;
-    match nix::unistd::seteuid(nix::unistd::Uid::from_raw(id)) {
-        Err(err) => panic!("failed seteuid {}", err),
-        Ok(_) => {}
+    if let Err(err) = nix::unistd::seteuid(nix::unistd::Uid::from_raw(ROOT_ID)) {
+        panic!("failed seteuid {}", err)
     }
-    match nix::unistd::setegid(nix::unistd::Gid::from_raw(id)) {
-        Err(err) => panic!("failed setedid{}", err),
-        Ok(_) => {}
+    if let Err(err) = nix::unistd::setegid(nix::unistd::Gid::from_raw(ROOT_ID)) {
+        panic!("failed setedid{}", err)
     }
-
-    match nix::unistd::setuid(nix::unistd::Uid::from_raw(id)) {
-        Err(err) => panic!("failed setuid {}", err),
-        Ok(_) => {}
+    if let Err(err) = nix::unistd::setuid(nix::unistd::Uid::from_raw(ROOT_ID)) {
+        panic!("failed setuid {}", err)
     }
-
-    match nix::unistd::setgid(nix::unistd::Gid::from_raw(id)) {
-        Err(err) => panic!("failed setdid{}", err),
-        Ok(_) => {}
+    if let Err(err) = nix::unistd::setgid(nix::unistd::Gid::from_raw(ROOT_ID)) {
+        panic!("failed setdid{}", err)
     }
 }

--- a/src/virsh.rs	Fri Oct 30 13:58:33 2020 +0900
+++ b/src/virsh.rs	Sun Nov 01 12:52:13 2020 +0900
@@ -13,7 +13,7 @@
         .output()
         .expect("failed to virsh");
     let virsh_list = String::from_utf8_lossy(&output.stdout);
-    let mut virsh_list = virsh_list.split("\n");
+    let mut virsh_list = virsh_list.split('\n');
 
     let info_msg = virsh_list.next().unwrap();
     let border_line = virsh_list.next().unwrap();
@@ -22,13 +22,13 @@
         border_line: String::from(border_line),
     };
 
-    return (
+    (
         ldump_msg,
         virsh_list
             .filter(|&x| x.contains(user_name))
             .map(|x| x.to_string())
             .collect(),
-    );
+    )
 }
 
 pub fn start_vm(vm_name: String) {