From 147ba0f00dad5ded569966430dbad529e82d05d5 Mon Sep 17 00:00:00 2001
From: Tony Murray <murraytony@gmail.com>
Date: Sun, 7 Jun 2020 23:18:18 -0500
Subject: [PATCH] Fix latency tab bugs (#11787)

when there is no latency data
fix smokeping error
---
 LibreNMS/Util/Smokeping.php                            | 4 ++--
 app/Http/Controllers/Device/Tabs/LatencyController.php | 9 +++++++--
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/LibreNMS/Util/Smokeping.php b/LibreNMS/Util/Smokeping.php
index 43c5a3124a..27b6c7ab03 100644
--- a/LibreNMS/Util/Smokeping.php
+++ b/LibreNMS/Util/Smokeping.php
@@ -48,11 +48,11 @@ class Smokeping
     {
         if (is_null($this->files) && Config::has('smokeping.dir')) {
             $dir = $this->generateFileName();
-            if (is_dir($dir)) {
+            if (is_dir($dir) && is_readable($dir)) {
                 foreach (array_diff(scandir($dir), ['.', '..']) as $file) {
                     if (stripos($file, '.rrd') !== false) {
                         if (strpos($file, '~') !== false) {
-                            list($target, $slave) = explode('~', $this->filenameToHostname($file));
+                            [$target, $slave] = explode('~', $this->filenameToHostname($file));
                             $this->files['in'][$target][$slave] = $file;
                             $this->files['out'][$slave][$target] = $file;
                         } else {
diff --git a/app/Http/Controllers/Device/Tabs/LatencyController.php b/app/Http/Controllers/Device/Tabs/LatencyController.php
index 094a7441c6..b3b987cf38 100644
--- a/app/Http/Controllers/Device/Tabs/LatencyController.php
+++ b/app/Http/Controllers/Device/Tabs/LatencyController.php
@@ -37,7 +37,8 @@ class LatencyController implements DeviceTab
 {
     public function visible(Device $device): bool
     {
-        return true;
+        return Config::get('smokeping.integration') || DB::table('device_perf')
+            ->where('device_id', $device->device_id)->exists();
     }
 
     public function slug(): string
@@ -61,7 +62,11 @@ class LatencyController implements DeviceTab
         $to = Request::get('dtpickerto', Carbon::now()->format(Config::get('dateformat.byminute')));
 
         $perf = $this->fetchPerfData($device, $from, $to);
-        $duration = abs(strtotime($perf->first()->date) - strtotime($perf->last()->date)) * 1000;
+
+        $duration = $perf && $perf->isNotEmpty()
+            ? abs(strtotime($perf->first()->date) - strtotime($perf->last()->date)) * 1000
+            : 0;
+
 
         $smokeping = new Smokeping($device);
         $smokeping_tabs = [];