Implement many process syscalls.

user/src/bin/user_shell.rs

@@ -12,7 +12,7 @@ const DL: u8 = 0x7fu8;
 const BS: u8 = 0x08u8;
 
 use alloc::string::String;
-use user_lib::{fork, exec, wait};
+use user_lib::{fork, exec, waitpid, yield_};
 use user_lib::console::getchar;
 
 #[no_mangle]
@@ -37,8 +37,17 @@ pub fn main() -> i32 {
                         unreachable!();
                     } else {
                         let mut xstate: i32 = 0;
-                        wait(&mut xstate);
-                        println!("Shell: Process {} exited with code {}", pid, xstate);
+                        let mut exit_pid: isize = 0;
+                        loop {
+                            exit_pid = waitpid(pid as usize, &mut xstate);
+                            if exit_pid == -1 {
+                                yield_();
+                            } else {
+                                assert_eq!(pid, exit_pid);
+                                println!("Shell: Process {} exited with code {}", pid, xstate);
+                                break;
+                            }
+                        }
                     }
                     line.clear();
                 }

user/src/lib.rs

@@ -42,7 +42,7 @@ fn main() -> i32 {
 
 pub fn read(fd: usize, buf: &mut [u8]) -> isize { sys_read(fd, buf) }
 pub fn write(fd: usize, buf: &[u8]) -> isize { sys_write(fd, buf) }
-pub fn exit(xstate: i32) -> ! { sys_exit(xstate); }
+pub fn exit(exit_code: i32) -> ! { sys_exit(exit_code); }
 pub fn yield_() -> isize { sys_yield() }
 pub fn get_time() -> isize { sys_get_time() }
 pub fn getpid() -> isize { sys_getpid() }

user/src/syscall.rs

@@ -29,8 +29,8 @@ pub fn sys_write(fd: usize, buffer: &[u8]) -> isize {
     syscall(SYSCALL_WRITE, [fd, buffer.as_ptr() as usize, buffer.len()])
 }
 
-pub fn sys_exit(xstate: i32) -> ! {
-    syscall(SYSCALL_EXIT, [xstate as usize, 0, 0]);
+pub fn sys_exit(exit_code: i32) -> ! {
+    syscall(SYSCALL_EXIT, [exit_code as usize, 0, 0]);
     panic!("sys_exit never returns!");
 }