ddns-update: do nothing if packages.archlinux32.org gives bogus content

1 files 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