From b5f194d20f3f7b2f9c3c6ee9156997c2c796054e Mon Sep 17 00:00:00 2001
From: Jiajie Chen <noc@jiegec.ac.cn>
Date: Wed, 17 Apr 2019 00:28:34 +0800
Subject: [PATCH] Fix get_ppid for init process

---
 kernel/src/syscall/proc.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/src/syscall/proc.rs b/kernel/src/syscall/proc.rs
index c6cc4ec..6f33cf8 100644
--- a/kernel/src/syscall/proc.rs
+++ b/kernel/src/syscall/proc.rs
@@ -231,7 +231,11 @@ pub fn sys_gettid() -> SysResult {
 
 /// Get the parent process id
 pub fn sys_getppid() -> SysResult {
-    Ok(process().parent.as_ref().unwrap().lock().pid.get())
+    if let Some(ref parent) = process().parent.as_ref() {
+        Ok(parent.lock().pid.get())
+    } else {
+        Ok(0)
+    }
 }
 
 /// Exit the current thread