Substituted to the original ch7 code.

user/src/bin/user_shell.rs

@@ -12,7 +12,16 @@ const DL: u8 = 0x7fu8;
 const BS: u8 = 0x08u8;
 
 use alloc::string::String;
-use user_lib::{fork, exec, waitpid};
+use alloc::vec::Vec;
+use user_lib::{
+    fork,
+    exec,
+    waitpid,
+    open,
+    OpenFlags,
+    close,
+    dup,
+};
 use user_lib::console::getchar;
 
 #[no_mangle]
@@ -26,11 +35,78 @@ pub fn main() -> i32 {
             LF | CR => {
                 println!("");
                 if !line.is_empty() {
-                    line.push('\0');
+                    let args: Vec<_> = line.as_str().split(' ').collect();
+                    let mut args_copy: Vec<String> = args
+                    .iter()
+                    .map(|&arg| {
+                        let mut string = String::new();
+                        string.push_str(arg);
+                        string
+                    })
+                    .collect();
+
+                    args_copy
+                    .iter_mut()
+                    .for_each(|string| {
+                        string.push('\0');
+                    });
+
+                    // redirect input
+                    let mut input = String::new();
+                    if let Some((idx, _)) = args_copy
+                    .iter()
+                    .enumerate()
+                    .find(|(_, arg)| arg.as_str() == "<\0") {
+                        input = args_copy[idx + 1].clone();
+                        args_copy.drain(idx..=idx + 1);
+                    }
+
+                    // redirect output
+                    let mut output = String::new();
+                    if let Some((idx, _)) = args_copy
+                    .iter()
+                    .enumerate()
+                    .find(|(_, arg)| arg.as_str() == ">\0") {
+                        output = args_copy[idx + 1].clone();
+                        args_copy.drain(idx..=idx + 1);
+                    }
+
+                    let mut args_addr: Vec<*const u8> = args_copy
+                        .iter()
+                        .map(|arg| arg.as_ptr())
+                        .collect();
+                    args_addr.push(0 as *const u8);
                     let pid = fork();
                     if pid == 0 {
+                        // input redirection
+                        if !input.is_empty() {
+                            let input_fd = open(input.as_str(), OpenFlags::RDONLY);
+                            if input_fd == -1 {
+                                println!("Error when opening file {}", input);
+                                return -4;
+                            }
+                            let input_fd = input_fd as usize;
+                            close(0);
+                            assert_eq!(dup(input_fd), 0);
+                            close(input_fd);
+                        }
+                        // output redirection
+                        if !output.is_empty() {
+                            let output_fd = open(
+                                output.as_str(),
+                                OpenFlags::CREATE | OpenFlags::WRONLY
+                            );
+                            if output_fd == -1 {
+                                println!("Error when opening file {}", output);
+                                return -4;
+                            }
+                            let output_fd = output_fd as usize;
+                            close(1);
+                            assert_eq!(dup(output_fd), 1);
+                            close(output_fd);
+                        }
                         // child process
-                        if exec(line.as_str()) == -1 {
+                        if exec(args_copy[0].as_str(), args_addr.as_slice()) == -1 {
                             println!("Error when executing!");
                             return -4;
                         }