From 7122321249ce1ee90196afea6f7d78de45ce87ad Mon Sep 17 00:00:00 2001
From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Tue, 15 Nov 2022 16:38:50 +0100
Subject: [PATCH] ntp: log added and removed sources

Log a message when a single NTP source or pool of sources is added or
removed. Use the INFO severity if it's a result of a chronyc command or
(re)load of sourcefiles (which are assumed to change over time), and
DEBUG for other contexts, e.g. sources loaded from the config, sources
removed when pruning pools after reaching maxsources, and other parts of
normal operation.
---
 ntp_sources.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/ntp_sources.c b/ntp_sources.c
index d46c211..fa562a1 100644
--- a/ntp_sources.c
+++ b/ntp_sources.c
@@ -317,6 +317,31 @@ rehash_records(void)
 
 /* ================================================== */
 
+static void
+log_source(SourceRecord *record, int addition, int once_per_pool)
+{
+  int pool, log_addr;
+  char *ip_str;
+
+  if (once_per_pool && record->pool_id != INVALID_POOL) {
+    if (get_pool(record->pool_id)->sources > 1)
+      return;
+    pool = 1;
+    log_addr = 0;
+  } else {
+    ip_str = UTI_IPToString(&record->remote_addr->ip_addr);
+    pool = 0;
+    log_addr = strcmp(record->name, ip_str) != 0;
+  }
+
+  LOG(LOG_GetContextSeverity(LOGC_Command | LOGC_SourceFile), "%s %s %s%s%s%s",
+      addition ? "Added" : "Removed", pool ? "pool" : "source",
+      log_addr ? ip_str : record->name,
+      log_addr ? " (" : "", log_addr ? record->name : "", log_addr ? ")" : "");
+}
+
+/* ================================================== */
+
 /* Procedure to add a new source */
 static NSR_Status
 add_source(NTP_Remote_Address *remote_addr, char *name, NTP_Source_Type type,
@@ -371,6 +396,8 @@ add_source(NTP_Remote_Address *remote_addr, char *name, NTP_Source_Type type,
       if (auto_start_sources && UTI_IsIPReal(&remote_addr->ip_addr))
         NCR_StartInstance(record->data);
 
+      log_source(record, 1, 1);
+
       /* The new instance is allowed to change its address immediately */
       handle_saved_address_update();
 
@@ -884,6 +911,7 @@ NSR_RemoveSource(IPAddr *address)
   if (find_slot(address, &slot) == 0)
     return NSR_NoSuchSource;
 
+  log_source(get_record(slot), 0, 0);
   clean_source_record(get_record(slot));
 
   /* Rehash the table to make sure there are no broken probe sequences.
@@ -906,6 +934,7 @@ NSR_RemoveSourcesById(uint32_t conf_id)
     record = get_record(i);
     if (!record->remote_addr || record->conf_id != conf_id)
       continue;
+    log_source(record, 0, 1);
     clean_source_record(record);
   }