Add sys_dup && support input/output redirection in user_shell

os/src/syscall/fs.rs

@@ -6,6 +6,7 @@ use crate::mm::{
 };
 use crate::task::{current_user_token, current_task};
 use crate::fs::{make_pipe, OpenFlags, open_file};
+use alloc::sync::Arc;
 
 pub fn sys_write(fd: usize, buf: *const u8, len: usize) -> isize {
     let token = current_user_token();
@@ -94,3 +95,17 @@ pub fn sys_pipe(pipe: *mut usize) -> isize {
     *translated_refmut(token, unsafe { pipe.add(1) }) = write_fd;
     0
 }
+
+pub fn sys_dup(fd: usize) -> isize {
+    let task = current_task().unwrap();
+    let mut inner = task.acquire_inner_lock();
+    if fd >= inner.fd_table.len() {
+        return -1;
+    }
+    if inner.fd_table[fd].is_none() {
+        return -1;
+    }
+    let new_fd = inner.alloc_fd();
+    inner.fd_table[new_fd] = Some(Arc::clone(inner.fd_table[fd].as_ref().unwrap()));
+    new_fd as isize
+}

os/src/syscall/mod.rs

@@ -1,3 +1,4 @@
+const SYSCALL_DUP: usize = 24;
 const SYSCALL_OPEN: usize = 56;
 const SYSCALL_CLOSE: usize = 57;
 const SYSCALL_PIPE: usize = 59;
@@ -19,6 +20,7 @@ use process::*;
 
 pub fn syscall(syscall_id: usize, args: [usize; 3]) -> isize {
     match syscall_id {
+        SYSCALL_DUP=> sys_dup(args[0]),
         SYSCALL_OPEN => sys_open(args[0] as *const u8, args[1] as u32),
         SYSCALL_CLOSE => sys_close(args[0]),
         SYSCALL_PIPE => sys_pipe(args[0] as *mut usize),

user/src/bin/cmdline_args.rs

@@ -10,7 +10,7 @@ extern crate user_lib;
 pub fn main(argc: usize, argv: &[&str]) -> i32 {
     println!("argc = {}", argc);
     for i in 0..argc {
-        println!("argc[{}] = {}", i, argv[i]);
+        println!("argv[{}] = {}", i, argv[i]);
     }
     0
 }

user/src/bin/user_shell.rs

@@ -13,7 +13,15 @@ const BS: u8 = 0x08u8;
 
 use alloc::string::String;
 use alloc::vec::Vec;
-use user_lib::{fork, exec, waitpid};
+use user_lib::{
+    fork,
+    exec,
+    waitpid,
+    open,
+    OpenFlags,
+    close,
+    dup,
+};
 use user_lib::console::getchar;
 
 #[no_mangle]
@@ -29,18 +37,40 @@ pub fn main() -> i32 {
                 if !line.is_empty() {
                     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();
+                    .iter()
+                    .map(|&arg| {
+                        let mut string = String::new();
+                        string.push_str(arg);
+                        string
+                    })
+                    .collect();
+
                     args_copy
-                        .iter_mut()
-                        .for_each(|string| {
-                            string.push('\0');
-                        });
+                    .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())
@@ -48,6 +78,33 @@ pub fn main() -> i32 {
                     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(args_copy[0].as_str(), args_addr.as_slice()) == -1 {
                             println!("Error when executing!");

user/src/lib.rs

@@ -69,6 +69,7 @@ bitflags! {
     }
 }
 
+pub fn dup(fd: usize) -> isize { sys_dup(fd) }
 pub fn open(path: &str, flags: OpenFlags) -> isize { sys_open(path, flags.bits) }
 pub fn close(fd: usize) -> isize { sys_close(fd) }
 pub fn pipe(pipe_fd: &mut [usize]) -> isize { sys_pipe(pipe_fd) }

user/src/syscall.rs

@@ -1,3 +1,4 @@
+const SYSCALL_DUP: usize = 24;
 const SYSCALL_OPEN: usize = 56;
 const SYSCALL_CLOSE: usize = 57;
 const SYSCALL_PIPE: usize = 59;
@@ -24,6 +25,10 @@ fn syscall(id: usize, args: [usize; 3]) -> isize {
     ret
 }
 
+pub fn sys_dup(fd: usize) -> isize {
+    syscall(SYSCALL_DUP, [fd, 0, 0])
+}
+
 pub fn sys_open(path: &str, flags: u32) -> isize {
     syscall(SYSCALL_OPEN, [path.as_ptr() as usize, flags as usize, 0])
 }