From f846ba11f2b8f7c2d4131f1cc23152fd50910f01 Mon Sep 17 00:00:00 2001
From: WangRunji <wangrunji0408@163.com>
Date: Tue, 23 Apr 2019 14:00:44 +0800
Subject: [PATCH] fix wait4 not removing child

---
 src/libos/src/process/exit.rs    | 12 +++++-------
 src/libos/src/process/process.rs |  6 ++++--
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/libos/src/process/exit.rs b/src/libos/src/process/exit.rs
index a7da5b33..621473cc 100644
--- a/src/libos/src/process/exit.rs
+++ b/src/libos/src/process/exit.rs
@@ -20,8 +20,7 @@ pub fn do_exit(exit_status: i32) {
     current.status = Status::ZOMBIE;
 
     // Update children
-    for child_weak in &current.children {
-        let child_ref = child_weak.upgrade().unwrap();
+    for child_ref in current.get_children_iter() {
         let mut child = child_ref.lock().unwrap();
         child.parent = Some(IDLE_PROCESS.clone());
     }
@@ -69,8 +68,7 @@ pub fn do_wait4(child_filter: &ChildProcessFilter, exit_status: &mut i32) -> Res
         let mut current = current_ref.lock().unwrap();
 
         let mut any_child_to_wait_for = false;
-        for child_weak in current.get_children() {
-            let child_ref = child_weak.upgrade().unwrap();
+        for child_ref in current.get_children_iter() {
             let child = child_ref.lock().unwrap();
 
             let may_wait_for = match child_filter {
@@ -82,8 +80,9 @@ pub fn do_wait4(child_filter: &ChildProcessFilter, exit_status: &mut i32) -> Res
                 continue;
             }
 
-            // Return immediately as a child that we wait for has alreay exited
+            // Return immediately as a child that we wait for has already exited
             if child.status == Status::ZOMBIE {
+                process_table::remove(child.pid);
                 return Ok(child.pid);
             }
 
@@ -107,8 +106,7 @@ pub fn do_wait4(child_filter: &ChildProcessFilter, exit_status: &mut i32) -> Res
     let mut current = current_ref.lock().unwrap();
     let child_i = {
         let mut child_i_opt = None;
-        for (child_i, child_weak) in current.children.iter().enumerate() {
-            let child_ref = child_weak.upgrade().unwrap();
+        for (child_i, child_ref) in current.get_children_iter().enumerate() {
             let child = child_ref.lock().unwrap();
             if child.get_pid() != child_pid {
                 continue;
diff --git a/src/libos/src/process/process.rs b/src/libos/src/process/process.rs
index fbfeffd3..2baedb06 100644
--- a/src/libos/src/process/process.rs
+++ b/src/libos/src/process/process.rs
@@ -88,8 +88,10 @@ impl Process {
     pub fn get_parent(&self) -> &ProcessRef {
         self.parent.as_ref().unwrap()
     }
-    pub fn get_children(&self) -> &[ProcessWeakRef] {
-        &self.children
+    pub fn get_children_iter(&self) -> impl Iterator<Item=ProcessRef> + '_ {
+        self.children
+            .iter()
+            .filter_map(|child_weak| child_weak.upgrade())
     }
     pub fn change_cwd(&mut self, path: &str) {
         if path.len() > 0 && path.as_bytes()[0] == b'/' {