Support cmdline_args when sys_exec.

os/src/syscall/process.rs

@@ -9,12 +9,15 @@ use crate::timer::get_time_ms;
 use crate::mm::{
     translated_str,
     translated_refmut,
+    translated_ref,
 };
 use crate::fs::{
     open_file,
     OpenFlags,
 };
 use alloc::sync::Arc;
+use alloc::vec::Vec;
+use alloc::string::String;
 
 pub fn sys_exit(exit_code: i32) -> ! {
     exit_current_and_run_next(exit_code);
@@ -48,14 +51,25 @@ pub fn sys_fork() -> isize {
     new_pid as isize
 }
 
-pub fn sys_exec(path: *const u8) -> isize {
+pub fn sys_exec(path: *const u8, mut args: *const usize) -> isize {
     let token = current_user_token();
     let path = translated_str(token, path);
+    let mut args_vec: Vec<String> = Vec::new();
+    loop {
+        let arg_str_ptr = *translated_ref(token, args);
+        if arg_str_ptr == 0 {
+            break;
+        }
+        args_vec.push(translated_str(token, arg_str_ptr as *const u8));
+        unsafe { args = args.add(1); }
+    }
     if let Some(app_inode) = open_file(path.as_str(), OpenFlags::RDONLY) {
         let all_data = app_inode.read_all();
         let task = current_task().unwrap();
-        task.exec(all_data.as_slice());
-        0
+        let argc = args_vec.len();
+        task.exec(all_data.as_slice(), args_vec);
+        // return argc because cx.x[10] will be covered with it later
+        argc as isize
     } else {
         -1
     }