Add fallback plan if InetAddress.getLocalHost() fails

pom.xml

@@ -5,7 +5,7 @@
 
     <groupId>io.github.theprez</groupId>
     <artifactId>mapepire-server</artifactId>
-    <version>2.1.5</version>
+    <version>2.1.6</version>
     <name>Mapepire (IBM i) Server Component</name>
     <description>Server-side support for Mapepire cloud-native database access layer.</description>
     <url>https://github.com/Mapepire-IBMi/mapepire-server/</url>

src/main/java/com/github/ibm/mapepire/certstuff/LocalHostResolver.java

@@ -0,0 +1,22 @@
+package com.github.ibm.mapepire.certstuff;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.InetAddress;
+
+import com.github.ibm.mapepire.Tracer;
+
+class LocalHostResolver {
+    static String getFQDN() throws IOException {
+        try {
+            return InetAddress.getLocalHost().getCanonicalHostName().toLowerCase();
+        } catch (IOException e) {
+            Tracer.warn(e);
+            Process p = Runtime.getRuntime().exec("/QOpenSys/usr/bin/hostname");
+            try (BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()))) {
+                return br.readLine().toLowerCase().trim();
+            }
+        }
+    }
+}

src/main/java/com/github/ibm/mapepire/certstuff/SelfSignedCertGenerator.java

@@ -21,8 +21,7 @@ public ServerCertInfo generate(final String _storePassword, final String _keyPas
         final File javaHome = new File(System.getProperty("java.home"));
         final File keytoolDir = new File(javaHome, "bin");
 
-        final InetAddress localHost = InetAddress.getLocalHost();
-        final String fqdn = localHost.getHostName();
+        final String fqdn = LocalHostResolver.getFQDN();
         final String dname =  String.format("cn=%s, ou=Web Socket Server, o=Db2 for IBM i, c=Unknown, st=Unknown", fqdn);
         final File keytoolPath = new File(keytoolDir, getKeytoolBinaryName());
         final String[] cmdArray = new String[] {

src/main/java/com/github/ibm/mapepire/certstuff/ServerCertGetter.java

@@ -72,7 +72,7 @@ private File findLetsEncryptCertDir() {
         }
 
         try {
-            String myHostName = InetAddress.getLocalHost().getCanonicalHostName().toLowerCase();
+            String myHostName = LocalHostResolver.getFQDN();
             Tracer.info("------we think our hostname is "+myHostName);
             for (File candidate : candidates) {
                 if (candidate.getName().equalsIgnoreCase(myHostName)) {