From 3c5b8b89e4fa60daf73d1f9ba17ded4ed3ee2410 Mon Sep 17 00:00:00 2001
From: Erich Eckner <git@eckner.net>
Date: Thu, 6 Dec 2018 08:59:42 +0100
Subject: ddns-update: do nothing if packages.archlinux32.org gives bogus
 content

---
 ddns-update | 47 ++++++++++++++++++++++++++++-------------------
 1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/ddns-update b/ddns-update
index 0476242..d6785d6 100755
--- a/ddns-update
+++ b/ddns-update
@@ -28,6 +28,29 @@ if [ $# -eq 1 ]; then
   exit
 fi
 
+mirrors=$(
+  curl -s 'https://packages.archlinux32.org/mirrors/status.php?tsv'
+)
+
+url_column=$(
+  printf '%s\n' "${mirrors}" | \
+    head -n1 | \
+    tr '\t' '\n' | \
+    grep -nxF 'url' | \
+    cut -d: -f1
+)
+recently_active_column=$(
+  printf '%s\n' "${mirrors}" | \
+    head -n1 | \
+    tr '\t' '\n' | \
+    grep -nxF 'recently_active' | \
+    cut -d: -f1
+)
+if [ -z "${url_column}" ] || [ -z "${recently_active_column}" ]; then
+  # https://packages.archlinux32.org/mirrors/status.php?tsv gave bogus content
+  exit
+fi
+
 {
   for type in 'A' 'AAAA'; do
     printf '%s\n' \
@@ -37,25 +60,11 @@ fi
       'send'
   done
   printf 'zone ddns.eckner.net.\n'
-  curl -s 'https://packages.archlinux32.org/mirrors/status.php?tsv' | \
-    {
-      read -r headers
-      url_column=$(
-        printf '%s\n' "${headers}" | \
-          tr '\t' '\n' | \
-          grep -nxF 'url' | \
-          cut -d: -f1
-      )
-      recently_active_column=$(
-        printf '%s\n' "${headers}" | \
-          tr '\t' '\n' | \
-          grep -nxF 'recently_active' | \
-          cut -d: -f1
-      )
-      awk '{
-        print $'"${recently_active_column}"' "\t" $'"${url_column}"'
-      }'
-    } | \
+  printf '%s\n' "${mirrors}" | \
+    sed '1d' | \
+    awk '{
+      print $'"${recently_active_column}"' "\t" $'"${url_column}"'
+    }' | \
     sed -n '
       s/^1\t//
       T
-- 
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