From aba58e5ee455c0639e93dff8e67b33ecaef50185 Mon Sep 17 00:00:00 2001
From: Ad Schellevis <ad@opnsense.org>
Date: Thu, 18 Nov 2021 17:06:40 +0100
Subject: [PATCH] Logging: Add a symlink for e.g. system.log to
 system_todaysdate.log for log parsing
 (https://github.com/opnsense/core/issues/4993)

same same as https://github.com/opnsense/core/commit/dd6a04a68a73f42cc1a6a63cebe568a6f6287bab, but different.
Concerns fixed in this commit:

o archive shouldn't generate files so old "archived" files remain untouched
o "latest.log" should point to the latest version know, which could be todays or a file from the past
o better to not remove links when unchanged to prevent excessive writes
---
 src/opnsense/scripts/syslog/log_archive | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/opnsense/scripts/syslog/log_archive b/src/opnsense/scripts/syslog/log_archive
index 5f45a45ad..69e0b31da 100755
--- a/src/opnsense/scripts/syslog/log_archive
+++ b/src/opnsense/scripts/syslog/log_archive
@@ -54,17 +54,17 @@ foreach(new RecursiveIteratorIterator($it) as $file) {
 
 // remove expired logs and set latest.log symlink
 foreach ($relevant_logs as $log_subject => $items)  {
+    rsort($items);
     if (count($items) > $preserve_logs) {
-        rsort($items);
         foreach (array_slice($items, $preserve_logs) as $filename) {
             @unlink($filename);
         }
     }
-
-    $target = "/var/log/{$log_subject}/{$log_subject}_" . date('Ymd') . '.log';
-    $link = "/var/log/{$log_subject}/latest.log";
-
-    @touch($target);
-    @unlink($link);
-    @symlink($target, $link);
+    // latest is always top of rsorted list $items[0]
+    $current_target = @readlink($link);
+    if ($current_target != $items[0]) {
+        $link = "/var/log/{$log_subject}/latest.log";
+        @unlink($link);
+        @symlink($items[0], $link);
+    }
 }