From 30495b995edb7f7bbb028c5c92341674aecc95d9 Mon Sep 17 00:00:00 2001
From: Andrew Engelbrecht <andrew@engelbrecht.io>
Date: Mon, 18 Oct 2021 21:15:54 -0400
Subject: [PATCH] error message when ssh connection is interrupted

Older, but fairly recent, versions of OpenSSH don't report a non-zero
exit code if an SSH client process is killed with SIGTERM. This patch
checks for a success or typical error message, otherwise it raises its
own error.
---
 kaya        | 12 +++++++++++-
 kaya-client |  3 +++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/kaya b/kaya
index 582f73c..c8f29f9 100755
--- a/kaya
+++ b/kaya
@@ -134,13 +134,23 @@ start-backup() {
     local password
     password="$(head -n1 "${password_file}")"
 
+    log_dump="$(mktemp)"
+
     # make the backup over a forwarded port
     cat << EOF | ssh -R "${remote_port}:localhost:${local_port}" "${remote_user}@${hostname}" kaya-client \
-        "${remote_port@Q}" "${hostname@Q}" "${backup_options[@]@Q}"
+        "${remote_port@Q}" "${hostname@Q}" "${backup_options[@]@Q}" \
+        | tee "${log_dump}" | grep -v "KAYA_SUCCESSFUL_BACKUP_MESSAGE"
 ${kaya_protocol_version}
 ${password}
 EOF
 
+    # confirm that the SSH session completed
+    if tail -1 "${log_dump}" | grep -v -e "^KAYA_SUCCESSFUL_BACKUP_MESSAGE" -e "^kaya-client: command exit code" ; then
+	rm "${log_dump}"
+	echo "kaya: backup interrupted or failed to complete" >&2
+	exit 1
+    fi
+    rm "${log_dump}"
 }
 
 main() {
diff --git a/kaya-client b/kaya-client
index 83ec93f..1a82f9b 100755
--- a/kaya-client
+++ b/kaya-client
@@ -50,4 +50,7 @@ ret=0
 if (( ret )); then
     echo "kaya-client: command exit code $ret: ${cmd[*]}" >&2
     exit $ret
+else
+    # needed in case ssh dies on the backup server, and exits with 0 (patched in OpenSSH version 8.8)
+    echo "KAYA_SUCCESSFUL_BACKUP_MESSAGE"
 fi
-- 
2.25.1