From f66029fe95ffc2010b0d3e435dbebf9ef7b7f849 Mon Sep 17 00:00:00 2001
From: Christoph <ckubu@oopen.de>
Date: Sat, 24 Feb 2018 13:56:55 +0100
Subject: [PATCH] Add script: 'check_ssh.sh'.

---
 check_ssh.sh | 185 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 185 insertions(+)
 create mode 100755 check_ssh.sh

diff --git a/check_ssh.sh b/check_ssh.sh
new file mode 100755
index 0000000..5485b16
--- /dev/null
+++ b/check_ssh.sh
@@ -0,0 +1,185 @@
+#!/usr/bin/env bash
+
+sshd_binary="$(which sshd)"
+
+check_string_ps="$sshd_binary"
+
+LOCK_DIR=`mktemp -d`
+
+
+#---------------------------------------
+#-----------------------------
+# Base Function(s)
+#-----------------------------
+#---------------------------------------
+
+fatal(){
+   echo ""
+   echo -e "   [ Fatal ] $*"
+   echo ""
+   echo -e "\tScript terminated.."
+   echo ""
+   rm -rf $LOCK_DIR
+   exit 1
+}
+
+error (){
+   echo ""
+   echo -e "   [ Error ] $*"
+   echo ""
+}
+
+warn (){
+   echo ""
+   echo -e "   [ Warn ]  $*"
+   echo ""
+}
+
+info (){
+   echo ""
+   echo -e "   [ Info ]  $*"
+   echo ""
+}
+
+ok (){
+   echo ""
+   echo -e "   [ Ok ]    $*"
+   echo ""
+}
+
+trim() {
+    local var="$*"
+    var="${var#"${var%%[![:space:]]*}"}"   # remove leading whitespace characters
+    var="${var%"${var##*[![:space:]]}"}"   # remove trailing whitespace characters
+    echo -n "$var"
+}
+
+
+#---------------------------------------
+#-----------------------------
+# Check some prerequisites
+#-----------------------------
+#---------------------------------------
+
+# - Running in a terminal?
+# -
+if [[ -t 1 ]] ; then
+      terminal=true
+      LOGGING=true
+else
+   terminal=false
+   LOGGING=false
+fi
+
+# - Is SSH Service installed ?
+# -
+if [[ -z "$sshd_binary" ]]; then
+   fatal "$(basename $0): SSH Service seems NOT to be installed"
+else
+   check_string_ps="$sshd_binary"
+fi
+
+
+# - Systemd supported ?
+# -
+systemd=$(which systemd)
+systemctl=$(which systemctl)
+
+systemd_supported=false
+if [[ -n "$systemd" ]] && [[ -n "$systemctl" ]] ; then
+   systemd_supported=true
+fi
+
+SSHD_SERVICE_FILE=
+SSHD_SYSV_INIT_SCRIPT=
+
+if $systemd_supported ; then
+   if systemctl -t service list-unit-files \
+         | grep -e "^ssh" \
+         | grep -q -E "(enabled|disabled)" 2> /devnull ; then
+
+      SSHD_SERVICE_FILE="$(systemctl -t service list-unit-files | grep -e "^ssh" | awk '{print$1}' | head -1)"
+   fi
+fi
+
+if [[ -z "$SSHD_SERVICE_FILE" ]]; then
+   if [[ -x "/etc/init.d/ssh" ]]; then
+      SSHD_SYSV_INIT_SCRIPT="/etc/init.d/ssh"
+   elif [[ -x "/etc/init.d/sshd" ]]; then
+      SSHD_SYSV_INIT_SCRIPT="/etc/init.d/sshd"
+   fi
+fi
+
+if [[ -z "$SSHD_SERVICE_FILE" ]] && [[ -z "$SSHD_SYSV_INIT_SCRIPT" ]] ; then
+   fatal 'Neither an init-script nor a service file for SSH found!'
+fi
+
+
+#---------------------------------------
+#-----------------------------
+# Check if SSH service is running
+#-----------------------------
+#---------------------------------------
+
+if $LOGGING ; then
+   echo -e "\n   Check if SSH service is running.."
+   echo -e "   ================================="
+fi
+if ! ps -e f | grep -E "[[:digit:]]\ ${check_string_ps}" | grep -v grep > /dev/null ; then
+   error "SSH service seems to be down! Trying to restart service now.."
+
+   if [[ -n "$SSHD_SERVICE_FILE" ]] ; then
+      $systemctl daemon-reload > /dev/null 2> ${LOCK_DIR}/err_msg.log
+      if [[ $? -ne 0 ]]; then
+         error "$(cat ${LOCK_DIR}/err_msg.log)"
+      fi
+      sleep 2
+      $systemctl stop $SSHD_SERVICE_FILE > /dev/null 2> ${LOCK_DIR}/err_msg.log
+      if [[ $? -ne 0 ]]; then
+         error "$(cat ${LOCK_DIR}/err_msg.log)"
+      fi
+      sleep 10
+      $systemctl start $SSHD_SERVICE_FILE > /dev/null 2> ${LOCK_DIR}/err_msg.log
+      if [[ $? -ne 0 ]]; then
+         error "$(cat ${LOCK_DIR}/err_msg.log)"
+      fi
+   else
+      $SSHD_SYSV_INIT_SCRIPT stop > /dev/null 2>&1
+      if [[ $? -ne 0 ]]; then
+         error "Stopping SSH service failed!"
+      fi
+      sleep 10
+      $SSHD_SYSV_INIT_SCRIPT start > /dev/null 2>&1
+      if [[ $? -ne 0 ]]; then
+         error "Starting SSH service failed!"
+      fi
+   fi
+
+   declare -i counter=0
+   PID=$(ps -e f | grep -E "[[:digit:]]\ ${check_string_ps}"| grep -v grep | awk '{print$2}')
+   while [[ "X${PID}" = "X" ]]; do
+      sleep 1
+      PID=$(ps -e f | grep -E "[[:digit:]]\ ${check_string_ps}"| grep -v grep | awk '{print$2}')
+      if [[ $counter -gt 10 ]]; then
+         break
+      else 
+         ((counter++))
+      fi
+   done
+
+   if [[ "X${PID}" = "X" ]] ; then
+      error "Restarting SSH service failed!"
+   else
+      ok "SSH service is up and running."
+   fi
+         
+else
+   if $LOGGING ; then
+      ok "SSH service is up and running."
+   fi
+fi
+
+rm -rf $LOCK_DIR
+exit 0
+
+