From b86bcff2ebec605f1975f06d4414e2854c8a543c Mon Sep 17 00:00:00 2001
From: ligd <liguiding1@xiaomi.com>
Date: Thu, 17 Jun 2021 23:04:04 +0800
Subject: [PATCH] serial: add ioctl TIOCNOTTY

Change-Id: I14ab1304d6330578423e0775f42faa8e19886fef
Signed-off-by: ligd <liguiding1@xiaomi.com>
---
 drivers/serial/serial.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c
index c7c13754a2e..26792547a99 100644
--- a/drivers/serial/serial.c
+++ b/drivers/serial/serial.c
@@ -1378,7 +1378,22 @@ static int uart_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
             {
               /* Save the PID of the recipient of the SIGINT signal. */
 
-              dev->pid = (pid_t)arg;
+              if ((int)arg < 0 || dev->pid >= 0)
+                {
+                  ret = -EINVAL;
+                }
+              else
+                {
+                  dev->pid = (pid_t)arg;
+                  ret = 0;
+                }
+            }
+            break;
+
+          case TIOCNOTTY:
+            {
+              dev->pid = (pid_t)-1;
+              ret = 0;
             }
             break;
 #endif