Fix vfork child process not close opened files

src/libos/src/fs/file_table.rs

@@ -21,6 +21,10 @@ impl FileTable {
         }
     }
 
+    pub fn table(&self) -> &Vec<Option<FileTableEntry>> {
+        &self.table
+    }
+
     pub fn dup(
         &mut self,
         fd: FileDesc,

src/libos/src/process/do_vfork.rs

@@ -94,6 +94,10 @@ fn restore_parent_process(mut context: *mut CpuContext, current_ref: &ThreadRef)
             return_errno!(EFAULT, "couldn't restore parent file table");
         }
     };
+
+    // Close all child opened files
+    close_files_opened_by_child(current_ref, &parent_file_table)?;
+
     let mut current_file_table = current_ref.files().lock().unwrap();
     *current_file_table = parent_file_table;
 
@@ -131,3 +135,24 @@ pub fn check_vfork_for_exec(current_ref: &ThreadRef) -> Option<(ThreadId, Option
         None
     }
 }
+
+fn close_files_opened_by_child(current: &ThreadRef, parent_file_table: &FileTable) -> Result<()> {
+    let current_file_table = current.files().lock().unwrap();
+    let child_open_fds: Vec<FileDesc> = current_file_table
+        .table()
+        .iter()
+        .enumerate()
+        .filter(|(fd, _entry)| {
+            // Entry is only shown in the child file table
+            _entry.is_some() && parent_file_table.get_entry(*fd as FileDesc).is_err()
+        })
+        .map(|(fd, entry)| fd as FileDesc)
+        .collect();
+
+    drop(current_file_table);
+
+    child_open_fds
+        .iter()
+        .for_each(|&fd| current.close_file(fd).expect("close child file error"));
+    Ok(())
+}