From 05bf567f3b7d555a32b134f2fca878c9f99936d0 Mon Sep 17 00:00:00 2001
From: JJL772 <jeremy.lorelli.1337@gmail.com>
Date: Wed, 21 Jul 2021 17:26:39 -0700
Subject: [PATCH] Fix segfault in dbtpn when value parameter is nullptr

Running 'dbtpn Record' in iocsh would result in a segfault.
---
 modules/database/src/ioc/db/dbNotify.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/modules/database/src/ioc/db/dbNotify.c b/modules/database/src/ioc/db/dbNotify.c
index e596285c2..7613f3672 100644
--- a/modules/database/src/ioc/db/dbNotify.c
+++ b/modules/database/src/ioc/db/dbNotify.c
@@ -613,8 +613,10 @@ long dbtpn(char *pname, char *pvalue)
     ptpnInfo = dbCalloc(1, sizeof(tpnInfo));
     ptpnInfo->ppn = ppn;
     ptpnInfo->callbackDone = epicsEventCreate(epicsEventEmpty);
-    strncpy(ptpnInfo->buffer, pvalue, 80);
-    ptpnInfo->buffer[79] = 0;
+    if (pvalue) {
+        strncpy(ptpnInfo->buffer, pvalue, sizeof(ptpnInfo->buffer));
+        ptpnInfo->buffer[sizeof(ptpnInfo->buffer)-1] = 0;
+    }
 
     ppn->usrPvt = ptpnInfo;
     epicsThreadCreate("dbtpn", epicsThreadPriorityHigh,