diff --git a/rust/src/io.rs b/rust/src/io.rs
index f586150..370101b 100644
--- a/rust/src/io.rs
+++ b/rust/src/io.rs
@@ -1,7 +1,6 @@
 use alloc::string::String;
 use alloc::vec::Vec;
 use core::fmt::{self, Write};
-use core::option::Option;
 
 use crate::syscall::{sys_read, sys_write};
 
@@ -25,13 +24,15 @@ pub fn print(args: fmt::Arguments) {
     StdOut.write_fmt(args).unwrap();
 }
 
-pub fn getc() -> Option<u8> {
+pub fn getc() -> u8 {
     let mut c = 0u8;
-    let ret = sys_read(STDIN, &mut c, 1);
-    match ret {
-        1 => Some(c),
-        0 => None,
-        _ => panic!(),
+    loop {
+        let len = sys_read(STDIN, &mut c, 1);
+        match len {
+            1 => return c,
+            0 => continue,
+            _ => panic!("read stdin len = {}", len),
+        }
     }
 }
 
@@ -47,7 +48,7 @@ pub fn get_line(history: &mut Vec<Vec<u8>>) -> String {
     let mut line_vec = Vec::with_capacity(512);
     let mut history_index = history.len();
     loop {
-        match getc().unwrap() {
+        match getc() {
             BS | DEL => {
                 // Backspace
                 if cursor > 0 {
@@ -78,9 +79,9 @@ pub fn get_line(history: &mut Vec<Vec<u8>>) -> String {
                 break;
             }
             ESC => {
-                match getc() .unwrap(){
+                match getc() {
                     b'[' => {
-                        match getc().unwrap() {
+                        match getc() {
                             b'D' => {
                                 // Left arrow
                                 if cursor > 0 {
diff --git a/rust/src/lang_items.rs b/rust/src/lang_items.rs
index f125f8c..a5421cb 100644
--- a/rust/src/lang_items.rs
+++ b/rust/src/lang_items.rs
@@ -1,5 +1,4 @@
-use crate::syscall::{sys_close, sys_dup2, sys_exit, sys_open};
-use crate::io::{O_RDONLY, O_WRONLY, STDIN, STDOUT};
+use crate::syscall::sys_exit;
 use crate::ALLOCATOR;
 
 use core::alloc::Layout;
@@ -11,21 +10,6 @@ fn main() {
     panic!("No main() linked");
 }
 
-fn initfd(fd2: usize, path: &str, open_flags: usize) -> i32 {
-    let fd1 = sys_open(path, open_flags);
-    if fd1 < 0 {
-        return fd1;
-    }
-    let mut ret = fd1;
-    let fd1 = fd1 as usize;
-    if fd1 != fd2 {
-        sys_close(fd2);
-        ret = sys_dup2(fd1, fd2);
-        sys_close(fd1);
-    }
-    return ret;
-}
-
 fn init_heap() {
     const HEAP_SIZE: usize = 0x1000;
     static mut HEAP: [u8; HEAP_SIZE] = [0; HEAP_SIZE];
@@ -34,15 +18,6 @@ fn init_heap() {
 
 #[no_mangle]
 pub extern "C" fn _start(_argc: isize, _argv: *const *const u8) -> ! {
-    let fd = initfd(STDIN, "stdin:", O_RDONLY);
-    if fd < 0 {
-        panic!("open <stdin> failed: {}.", fd);
-    }
-    let fd = initfd(STDOUT, "stdout:", O_WRONLY);
-    if fd < 0 {
-        panic!("open <stdout> failed: {}.", fd);
-    }
-
     init_heap();
     main();
     sys_exit(0)
@@ -53,9 +28,7 @@ fn eh_personality() {}
 
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {
-    let location = info.location().unwrap();
-    let message = info.message().unwrap();
-    println!("\n\nPANIC in {} at line {}\n    {}", location.file(), location.line(), message);
+    println!("\n\n{}", info);
     sys_exit(1)
 }
 
@@ -66,5 +39,5 @@ fn oom(_: Layout) -> ! {
 
 #[no_mangle]
 pub extern "C" fn abort() -> ! {
-    sys_exit(2)
+    panic!("abort");
 }