From 752ca97f7eb0659ebc6828ed7199479f03a12739 Mon Sep 17 00:00:00 2001
From: Andrew Johnson <anj@anl.gov>
Date: Tue, 21 Jun 2022 17:23:05 -0500
Subject: [PATCH] VxWorks: Stop VxWorks clock sync if EPICS_TS_FORCE_NTPTIME

Use ipcom_ipd_kill() to do it properly, announce when doing it.
Suspending the ipsntps task is dangerous, can hang the OS so
don't try to kill it if user already suspended the task.
Also drops checks for the "ipntpd" thread, not used.
---
 modules/libcom/src/osi/os/vxWorks/osdTime.cpp | 54 ++++++++++---------
 1 file changed, 28 insertions(+), 26 deletions(-)

diff --git a/modules/libcom/src/osi/os/vxWorks/osdTime.cpp b/modules/libcom/src/osi/os/vxWorks/osdTime.cpp
index 7275d8d16..fe4bfc410 100644
--- a/modules/libcom/src/osi/os/vxWorks/osdTime.cpp
+++ b/modules/libcom/src/osi/os/vxWorks/osdTime.cpp
@@ -23,6 +23,7 @@
 #include "osiClockTime.h"
 #include "generalTimeSup.h"
 #include "envDefs.h"
+#include "epicsFindSymbol.h"
 
 #define NTP_REQUEST_TIMEOUT 4 /* seconds */
 
@@ -31,7 +32,7 @@ extern "C" {
 }
 
 static char sntp_sync_task[] = "ipsntps";
-static char ntp_daemon[] = "ipntpd";
+typedef int (*ipcom_ipd_kill_t)(const char *);
 
 static const char *pserverAddr = NULL;
 static CLOCKTIME_SYNCHOOK prevHook;
@@ -65,7 +66,7 @@ static int timeRegister(void)
         if (tz && *tz) {
             epicsEnvSet("TZ", tz);
 
-            /* Call tz2timezone() from the sync thread, needs the year */
+            // Call tz2timezone() from the sync thread, needs the year
             prevHook = ClockTime_syncHook;
             ClockTime_syncHook = timeSync;
         }
@@ -76,29 +77,37 @@ static int timeRegister(void)
     // Define EPICS_TS_FORCE_NTPTIME to force use of NTPTime provider
     bool useNTP = getenv("EPICS_TS_FORCE_NTPTIME") != NULL;
 
-    if (!useNTP) {
-        int tid;
-        if ((tid = taskNameToId(sntp_sync_task)) != ERROR ||
-            (tid = taskNameToId(ntp_daemon)) != ERROR) {
-            // A VxWorks 6 SNTP/NTP sync task exists
-            struct timespec clockNow;
+    // VxWorks 6 may have a clock sync task running
+    int tid = taskNameToId(sntp_sync_task);
+    struct timespec clockNow;
+    if (tid != ERROR &&
+        clock_gettime(CLOCK_REALTIME, &clockNow) == OK &&
+        clockNow.tv_sec > BUILD_TIME) {
+        // Clock appears set
+        tz2timezone();
+    }
+    else {
+        // No clock sync task or it's broken, start our own
+        useNTP = 1;
+    }
 
-            useNTP = taskIsSuspended(tid) ||
-                clock_gettime(CLOCK_REALTIME, &clockNow) != OK ||
-                clockNow.tv_sec < BUILD_TIME;
+    if (useNTP && tid != ERROR) {
+        // EPICS_TS_FORCE_NTPTIME was set, stop the OS sync task
+        ipcom_ipd_kill_t ipcom_ipd_kill =
+            (ipcom_ipd_kill_t) epicsFindSymbol("ipcom_ipd_kill");
 
-            if (!useNTP) // Clock should be sync'd so we can run this:
-                tz2timezone();
+        if (ipcom_ipd_kill && !taskIsSuspended(tid)) {
+            printf("timeRegister: Stopping VxWorks clock sync task\n");
+            ipcom_ipd_kill("ipsntp");
         }
-        else
-            useNTP = 1;
     }
 
     if (useNTP) {
         // Start NTP first so it can be used to sync ClockTime
         NTPTime_Init(100);
         ClockTime_Init(CLOCKTIME_SYNC);
-    } else {
+    }
+    else {
         ClockTime_Init(CLOCKTIME_NOSYNC);
     }
     osdMonotonicInit();
@@ -138,17 +147,10 @@ void osdNTPReport(void)
 void osdClockReport(int level)
 {
     const char * ntpTask;
-    int tid;
+    int tid = taskNameToId(sntp_sync_task);
 
-    if ((tid = taskNameToId(sntp_sync_task)) != ERROR)
-        ntpTask = sntp_sync_task;
-    else if ((tid = taskNameToId(ntp_daemon)) != ERROR)
-        ntpTask = ntp_daemon;
-    else {
-        printf("No VxWorks OS clock sync tasks exist\n");
-        return;
-    }
-    printf("VxWorks OS clock sync task '%s' is %s\n", ntpTask,
+    printf("VxWorks clock sync task '%s' is %s\n", sntp_sync_task,
+        (tid == ERROR) ? "not running" :
         taskIsSuspended(tid) ? "suspended" : "running");
 }