From 5cb9f3aaa33d8ca3ff1a55a5ef0ac2b7a53293e8 Mon Sep 17 00:00:00 2001
From: Vlastimil Holer <vholer@opennebula.io>
Date: Thu, 21 Oct 2021 10:57:07 +0200
Subject: [PATCH] F #248: Restart syslog on hostname change

Closes #248
---
 src/etc/init.d/one-context##apk.one       |  2 +-
 src/etc/init.d/one-context-local##apk.one |  4 +-
 src/etc/one-context.d/net-15-hostname     | 48 +++++++++++++++++------
 3 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/src/etc/init.d/one-context##apk.one b/src/etc/init.d/one-context##apk.one
index 2ac7fba..13abc67 100755
--- a/src/etc/init.d/one-context##apk.one
+++ b/src/etc/init.d/one-context##apk.one
@@ -21,7 +21,7 @@ name="OpenNebula contextualization"
 depend() {
 	use one-context-local net
 	before sshd
-	use logger
+	after logger
 	keyword -stop -shutdown
 }
 
diff --git a/src/etc/init.d/one-context-local##apk.one b/src/etc/init.d/one-context-local##apk.one
index f2b38f1..30a919e 100755
--- a/src/etc/init.d/one-context-local##apk.one
+++ b/src/etc/init.d/one-context-local##apk.one
@@ -15,13 +15,13 @@
 # See the License for the specific language governing permissions and        #
 # limitations under the License.                                             #
 #--------------------------------------------------------------------------- #
-#
+
 name="OpenNebula pre-networking contextualization"
 
 depend() {
 	need localmount udev udev-trigger udev-settle
 	before net
-	use logger
+	after logger
 	keyword -stop -shutdown
 }
 
diff --git a/src/etc/one-context.d/net-15-hostname b/src/etc/one-context.d/net-15-hostname
index e429b9e..88bcec3 100755
--- a/src/etc/one-context.d/net-15-hostname
+++ b/src/etc/one-context.d/net-15-hostname
@@ -23,29 +23,53 @@ else
     SED_I="sed -i''"
 fi
 
+# Detects suitable running syslog service and restarts it
+# to propagate the changed hostname into the logs
+# (otherwise old or default value remains until reboot)
+function restart_syslog() {
+    for _name in syslog syslogd rsyslog; do
+        if LANG=C systemctl is-active "${_name}" >/dev/null 2>&1; then
+            systemctl restart "${_name}" && return
+        elif service "${_name}" status >/dev/null 2>&1; then
+            service "${_name}" restart && return
+        fi
+    done
+}
+
 function set_hostname() {
-    local hostname=$1
+    local _hostname=$1
+
+    # remember currently set hostname to detect a change
+    local _old_hostname
+    _old_hostname=$(hostname)
 
     if [ -d /run/systemd/system/ ] && hostnamectl status >/dev/null 2>/dev/null; then
-        hostnamectl set-hostname --static "${hostname}"
+        hostnamectl set-hostname --static "${_hostname}"
     else
         if [ -f /etc/sysconfig/network ]; then
             eval "${SED_I} '/^HOSTNAME=.*$/d' /etc/sysconfig/network"
-            echo "HOSTNAME=${hostname}" >>/etc/sysconfig/network
+            echo "HOSTNAME=${_hostname}" >>/etc/sysconfig/network
         elif [ "${_kernel}" = 'FreeBSD' ]; then
-            sysrc hostname="${hostname}"
+            sysrc hostname="${_hostname}"
         else
-            echo "${hostname}" >/etc/hostname
+            echo "${_hostname}" >/etc/hostname
         fi
 
-        hostname "${hostname}"
+        hostname "${_hostname}"
+    fi
+
+    # restart syslog if actual hostname changed
+    if [ "${_old_hostname}" != "$(hostname)" ]; then
+        restart_syslog
     fi
 }
 
 function set_domainname() {
-    domain=$1
+    local _domain=$1
+
+    touch /etc/resolv.conf
     eval "${SED_I} -e '/^domain .*/d' /etc/resolv.conf"
-    echo "domain ${domain}" >>/etc/resolv.conf
+    echo "domain ${_domain}" >>/etc/resolv.conf
 }
 
 function get_first_ip() {
@@ -131,6 +155,10 @@ if [ -n "${name}" ]; then
         domain=''
     fi
 
+    if [ -n "${domain}" ]; then
+        set_domainname "${domain}"
+    fi
+
     # FreeBSD
     if [ "${_kernel}" = 'FreeBSD' ]; then
         set_hostname "${name}"
@@ -138,10 +166,6 @@ if [ -n "${name}" ]; then
         set_hostname "${hostname}"
     fi
 
-    if [ -n "${domain}" ]; then
-        set_domainname "${domain}"
-    fi
-
     if [ -n "${DNS_HOSTNAME}" ]; then
         host_ip=$first_ip
     else