Honor $JENKINS_HOME.

Honor $JENKINS_HOME (just like we used to do $HUDSON_HOME)
We still fall back to $HUDSON_HOME every step of the way
for maximum backward compatibility.

I wasn't initially planning to do this for the first version,
but working on native packages made me think we should deliver this.

core/src/main/java/hudson/Main.java

@@ -64,7 +64,7 @@ public class Main {
     public static int run(String[] args) throws Exception {
         String home = getHudsonHome();
         if (home==null) {
-            System.err.println("HUDSON_HOME is not set.");
+            System.err.println("JENKINS_HOME is not set.");
             return -1;
         }
         if (args.length < 2) {
@@ -76,7 +76,9 @@ public class Main {
     }
 
     private static String getHudsonHome() {
-        return EnvVars.masterEnvVars.get("HUDSON_HOME");
+        String home = EnvVars.masterEnvVars.get("JENKINS_HOME");
+        if (home!=null) return home;
+        return EnvVars.masterEnvVars.get("JENKINS_HOME");
     }
 
     /**

core/src/main/java/hudson/WebAppMain.java

@@ -261,36 +261,46 @@ public final class WebAppMain implements ServletContextListener {
     }
 
     /**
-     * Determines the home directory for Hudson.
+     * Determines the home directory for Jenkins.
      *
+     * <p>
+     * We look for a setting that affects the smallest scope first, then bigger ones later.
+     *
+     * <p>
      * People makes configuration mistakes, so we are trying to be nice
      * with those by doing {@link String#trim()}.
      */
     private File getHomeDir(ServletContextEvent event) {
         // check JNDI for the home directory first
-        try {
-            InitialContext iniCtxt = new InitialContext();
-            Context env = (Context) iniCtxt.lookup("java:comp/env");
-            String value = (String) env.lookup("HUDSON_HOME");
-            if(value!=null && value.trim().length()>0)
-                return new File(value.trim());
-            // look at one more place. See issue #1314 
-            value = (String) iniCtxt.lookup("HUDSON_HOME");
-            if(value!=null && value.trim().length()>0)
-                return new File(value.trim());
-        } catch (NamingException e) {
-            // ignore
+        for (String name : HOME_NAMES) {
+            try {
+                InitialContext iniCtxt = new InitialContext();
+                Context env = (Context) iniCtxt.lookup("java:comp/env");
+                String value = (String) env.lookup(name);
+                if(value!=null && value.trim().length()>0)
+                    return new File(value.trim());
+                // look at one more place. See issue #1314
+                value = (String) iniCtxt.lookup(name);
+                if(value!=null && value.trim().length()>0)
+                    return new File(value.trim());
+            } catch (NamingException e) {
+                // ignore
+            }
+        }
+
+        // next the system property
+        for (String name : HOME_NAMES) {
+            String sysProp = System.getProperty(name);
+            if(sysProp!=null)
+                return new File(sysProp.trim());
         }
 
-        // finally check the system property
-        String sysProp = System.getProperty("HUDSON_HOME");
-        if(sysProp!=null)
-            return new File(sysProp.trim());
-        
         // look at the env var next
-        String env = EnvVars.masterEnvVars.get("HUDSON_HOME");
-        if(env!=null)
-            return new File(env.trim()).getAbsoluteFile();
+        for (String name : HOME_NAMES) {
+            String env = EnvVars.masterEnvVars.get(name);
+            if(env!=null)
+                return new File(env.trim()).getAbsoluteFile();
+        }
 
         // otherwise pick a place by ourselves
 
@@ -304,8 +314,11 @@ public final class WebAppMain implements ServletContextListener {
                 return ws;
         }
 
-        // if for some reason we can't put it within the webapp, use home directory.
-        return new File(new File(System.getProperty("user.home")),".hudson");
+        File legacyHome = new File(new File(System.getProperty("user.home")), ".hudson");
+        if (legacyHome.exists())
+            return legacyHome; // before rename, this is where it was stored
+
+        return new File(new File(System.getProperty("user.home")), ".jenkins");
     }
 
     public void contextDestroyed(ServletContextEvent event) {
@@ -320,4 +333,6 @@ public final class WebAppMain implements ServletContextListener {
 
     private static final Logger LOGGER = Logger.getLogger(WebAppMain.class.getName());
 
+
+    private static final String[] HOME_NAMES = {"JENKINS_HOME","HUDSON_HOME"};
 }

core/src/main/java/hudson/diagnosis/HudsonHomeDiskUsageChecker.java

@@ -31,7 +31,7 @@ import org.jvnet.animal_sniffer.IgnoreJRERequirement;
 import java.util.logging.Logger;
 
 /**
- * Periodically checks the disk usage of <tt>HUDSON_HOME</tt>,
+ * Periodically checks the disk usage of <tt>JENKINS_HOME</tt>,
  * and activate {@link HudsonHomeDiskUsageMonitor} if necessary.
  *
  * @author Kohsuke Kawaguchi
@@ -49,12 +49,12 @@ public class HudsonHomeDiskUsageChecker extends PeriodicWork {
             long total = Hudson.getInstance().getRootDir().getTotalSpace();
             if(free<=0 || total<=0) {
                 // information unavailable. pointless to try.
-                LOGGER.info("HUDSON_HOME disk usage information isn't available. aborting to monitor");
+                LOGGER.info("JENKINS_HOME disk usage information isn't available. aborting to monitor");
                 cancel();
                 return;
             }
 
-            LOGGER.fine("Monitoring disk usage of HUDSON_HOME. total="+total+" free="+free);
+            LOGGER.fine("Monitoring disk usage of JENKINS_HOME. total="+total+" free="+free);
 
 
             // if it's more than 90% full and less than the minimum, activate
@@ -63,7 +63,7 @@ public class HudsonHomeDiskUsageChecker extends PeriodicWork {
             HudsonHomeDiskUsageMonitor.get().activated = (total/free>10 && free< FREE_SPACE_THRESHOLD);
         } catch (LinkageError _) {
             // pre Mustang
-            LOGGER.info("Not on JDK6. Cannot monitor HUDSON_HOME disk usage");
+            LOGGER.info("Not on JDK6. Cannot monitor JENKINS_HOME disk usage");
             cancel();
         }
     }

core/src/main/java/hudson/diagnosis/HudsonHomeDiskUsageMonitor.java

@@ -37,7 +37,7 @@ import java.io.IOException;
 import java.util.List;
 
 /**
- * Monitors the disk usage of <tt>HUDSON_HOME</tt>, and if it's almost filled up, warn the user.
+ * Monitors the disk usage of <tt>JENKINS_HOME</tt>, and if it's almost filled up, warn the user.
  *
  * @author Kohsuke Kawaguchi
  */
@@ -90,13 +90,13 @@ public final class HudsonHomeDiskUsageMonitor extends AdministrativeMonitor {
     }
 
     /**
-     * Extension point for suggesting solutions for full HUDSON_HOME.
+     * Extension point for suggesting solutions for full JENKINS_HOME.
      *
      * <h3>Views</h3>
      * <dl>
      * <dt>message.jelly</dt>
      * <dd>
-     * This view is rendered inside an LI tag as a possible solution to the full HUDSON_HOME problem.
+     * This view is rendered inside an LI tag as a possible solution to the full JENKINS_HOME problem.
      * </dd>
      * </dl>
      */

core/src/main/java/hudson/init/InitStrategy.java

@@ -32,7 +32,7 @@ public class InitStrategy {
      * Returns the list of *.hpi and *.hpl to expand and load.
      *
      * <p>
-     * Normally we look at {@code $HUDSON_HOME/plugins/*.hpi} and *.hpl.
+     * Normally we look at {@code $JENKINS_HOME/plugins/*.hpi} and *.hpl.
      *
      * @return
      *      never null but can be empty. The list can contain different versions of the same plugin,

core/src/main/java/hudson/model/Hudson.java

@@ -2363,7 +2363,7 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
             pluginManager.stop();
 
         if(getRootDir().exists())
-            // if we are aborting because we failed to create HUDSON_HOME,
+            // if we are aborting because we failed to create JENKINS_HOME,
             // don't try to save. Issue #536
             getQueue().save();
 
@@ -2917,7 +2917,7 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
     }
 
     /**
-     * Binds /userContent/... to $HUDSON_HOME/userContent.
+     * Binds /userContent/... to $JENKINS_HOME/userContent.
      */
     public DirectoryBrowserSupport doUserContent() {
         return new DirectoryBrowserSupport(this,getRootPath().child("userContent"),"User content","folder.gif",true);

core/src/main/java/hudson/model/Run.java

@@ -1771,8 +1771,8 @@ public abstract class Run <JobT extends Job<JobT,RunT>,RunT extends Run<JobT,Run
             env.put("JOB_URL", rootUrl+getParent().getUrl());
         }
         
-        if(!env.containsKey("HUDSON_HOME"))
-            env.put("HUDSON_HOME", Hudson.getInstance().getRootDir().getPath() );
+        env.put("JENKINS_HOME", Hudson.getInstance().getRootDir().getPath() );
+        env.put("HUDSON_HOME", Hudson.getInstance().getRootDir().getPath() );   // legacy compatibility
 
         Thread t = Thread.currentThread();
         if (t instanceof Executor) {

core/src/main/java/hudson/os/solaris/ZFSInstaller.java

@@ -62,14 +62,14 @@ import java.util.logging.Level;
 import java.util.logging.Logger;
 
 /**
- * Encourages the user to migrate HUDSON_HOME on a ZFS file system. 
+ * Encourages the user to migrate JENKINS_HOME on a ZFS file system.
  *
  * @author Kohsuke Kawaguchi
  * @since 1.283
  */
 public class ZFSInstaller extends AdministrativeMonitor implements Serializable {
     /**
-     * True if $HUDSON_HOME is a ZFS file system by itself.
+     * True if $JENKINS_HOME is a ZFS file system by itself.
      */
     private final boolean active = shouldBeActive();
 
@@ -302,7 +302,7 @@ public class ZFSInstaller extends AdministrativeMonitor implements Serializable
     }
 
     /**
-     * Migrates $HUDSON_HOME to a new ZFS file system.
+     * Migrates $JENKINS_HOME to a new ZFS file system.
      *
      * TODO: do this in a separate JVM to elevate the privilege.
      *

core/src/main/java/hudson/util/DoubleLaunchChecker.java

@@ -42,7 +42,7 @@ import java.lang.management.ManagementFactory;
 import java.lang.reflect.Method;
 
 /**
- * Makes sure that no other Hudson uses our <tt>HUDSON_HOME</tt> directory,
+ * Makes sure that no other Hudson uses our <tt>JENKINS_HOME</tt> directory,
  * to forestall the problem of running multiple instances of Hudson that point to the same data directory.
  *
  * <p>