From 6b53a4fac483c092e498acb2b5b79ac1bc622a3a Mon Sep 17 00:00:00 2001
From: zzz <zzz@mail.i2p>
Date: Sun, 16 Sep 2018 11:29:03 +0000
Subject: [PATCH] Build: Fix hang with Tomcat 8.5.33+ (ticket #2307)

---
 apps/i2ptunnel/java/build.xml                 |  4 +--
 .../java/src/net/i2p/servlet/util/JspC.java   | 34 +++++++++++++++++++
 apps/routerconsole/java/build.xml             | 30 ++++++++++++++--
 apps/susidns/src/build.xml                    |  4 ++-
 4 files changed, 67 insertions(+), 5 deletions(-)
 create mode 100644 apps/jetty/java/src/net/i2p/servlet/util/JspC.java

diff --git a/apps/i2ptunnel/java/build.xml b/apps/i2ptunnel/java/build.xml
index d3a9a5d8a..04e790839 100644
--- a/apps/i2ptunnel/java/build.xml
+++ b/apps/i2ptunnel/java/build.xml
@@ -305,8 +305,8 @@
         <delete file="../jsp/web-out.xml" />
         <mkdir dir="../jsp/WEB-INF/" />
         <mkdir dir="../jsp/WEB-INF/classes" />
-        <!-- there are various jspc ant tasks, but they all seem a bit flakey -->
-        <java classname="org.apache.jasper.JspC" fork="true" failonerror="true">
+        <!-- See apps/routerconsole/java/build.xml for important JspC build documentation -->
+        <java classname="net.i2p.servlet.util.JspC" fork="true" failonerror="true">
             <classpath>
                 <pathelement location="../../jetty/jettylib/jasper-runtime.jar" />
                 <pathelement location="../../jetty/jettylib/javax.servlet.jar" />
diff --git a/apps/jetty/java/src/net/i2p/servlet/util/JspC.java b/apps/jetty/java/src/net/i2p/servlet/util/JspC.java
new file mode 100644
index 000000000..02b7040b3
--- /dev/null
+++ b/apps/jetty/java/src/net/i2p/servlet/util/JspC.java
@@ -0,0 +1,34 @@
+package net.i2p.servlet.util;
+
+import java.lang.reflect.Method;
+
+/**
+ *  Simply call org.apache.jasper.JspC, then exit.
+ *
+ *  As of Tomcat 8.5.33, forking their JspC won't complete,
+ *  because the JspC compilation is now threaded and the thread pool workers aren't daemons.
+ *  May be fixed in a future release, maybe not, but we don't know what version distros may have.
+ *
+ *  https://tomcat.apache.org/tomcat-8.5-doc/changelog.html
+ *  https://bz.apache.org/bugzilla/show_bug.cgi?id=53492
+ *
+ *  We could set fork=false in build.xml, but then the paths are all wrong.
+ *  Only for use in build scripts, obviously not a public API.
+ *  See apps/routerconsole/java/build.xml for more information.
+ *
+ *  @since 0.9.37
+ */
+public class JspC {
+    public static void main(String args[]) {
+       try {
+           String cls = "org.apache.jasper.JspC";
+           Class<?> c = Class.forName(cls, true, ClassLoader.getSystemClassLoader());
+           Method main = c.getMethod("main", String[].class);
+           main.invoke(null, (Object) args);
+           System.exit(0);
+       } catch (Exception e) {
+           e.printStackTrace();
+           System.exit(1);
+       }
+    }
+}
diff --git a/apps/routerconsole/java/build.xml b/apps/routerconsole/java/build.xml
index 1f68546bb..294023a98 100644
--- a/apps/routerconsole/java/build.xml
+++ b/apps/routerconsole/java/build.xml
@@ -353,7 +353,13 @@
         <mkdir dir="../jsp/WEB-INF/" />
         <mkdir dir="../jsp/WEB-INF/classes" />
 
-        <!-- there are various jspc ant tasks, but they all seem a bit flakey -->
+        <!-- There are various jspc ant tasks, but they all seem a bit flakey.
+             Warning - jspC will fail on unknown options,
+             check oldest libtomcat8-java distro package version we use.
+             Jessie has 8.0.14; xenial has 8.0.32; we bundle for precise/trusty.
+             Add below to get supported options:
+                <arg value="-help" />
+          -->
         <!--
            **     Usage: jspc <options> <jsp files>
            **     where jsp files is
@@ -381,8 +387,28 @@
            **         -classpath <path>  Overrides java.class.path system property
            **         -xpoweredBy        Add X-Powered-By response header
            **         -trimSpaces        Trim spaces in template text between actions, directives
+           **     Following as of ?.?.??:
+           **         -javaEncoding <enc> Set the encoding charset for Java classes (default UTF-8)
+           **         -source <version>   Set the -source argument to the compiler (default 1.7)
+           **         -target <version>   Set the -target argument to the compiler (default 1.7)
+           **     Following as of 8.5.33:
+           **         -threadCount <count>  Number of threads to use for compilation.
+           **                               (default one per core)
+           **                               ("2.0C" means two threads per core)
         -->
-        <java classname="org.apache.jasper.JspC" fork="true" failonerror="true">
+        <!--
+           **  Simply call org.apache.jasper.JspC, then exit.
+           **
+           **  As of Tomcat 8.5.33, forking their JspC won't complete,
+           **  because the JspC compilation is now threaded and the thread pool workers aren't daemons.
+           **  May be fixed in a future release, maybe not, but we don't know what version distros may have.
+           **
+           **  https://tomcat.apache.org/tomcat-8.5-doc/changelog.html
+           **  https://bz.apache.org/bugzilla/show_bug.cgi?id=53492
+           **
+           **  We could set fork=false in build.xml, but then the paths are all wrong.
+        -->
+        <java classname="net.i2p.servlet.util.JspC" fork="true" failonerror="true">
             <!-- this prevents tomcat from complaining in debian builds -->
             <jvmarg value="-Dtomcat.util.scan.StandardJarScanFilter.jarsToSkip=commons-collections.jar,junit.jar,junit4.jar" />
             <classpath>
diff --git a/apps/susidns/src/build.xml b/apps/susidns/src/build.xml
index ad07268eb..0eaac0d4d 100644
--- a/apps/susidns/src/build.xml
+++ b/apps/susidns/src/build.xml
@@ -30,6 +30,7 @@
 		<pathelement location="lib/standard.jar" />
 		<pathelement location="${lib}/jasper-runtime.jar" />
 		<pathelement location="${lib}/jetty-util.jar" />
+		<pathelement location="${lib}/jetty-i2p.jar" />
 		<pathelement location="${ant.home}/lib/ant.jar" />
 		<pathelement location="../../../core/java/build/i2p.jar" />
 		<pathelement location="../../addressbook/dist/addressbook.jar" />
@@ -69,7 +70,8 @@
         <delete file="WEB-INF/web-out.xml" />
     	<mkdir dir="${tmp}" />
         <echo message="Ignore any warning about /WEB-INF/web.xml not found" />
-        <java classname="org.apache.jasper.JspC" fork="true" classpathref="cp" failonerror="true">
+        <!-- See apps/routerconsole/java/build.xml for important JspC build documentation -->
+        <java classname="net.i2p.servlet.util.JspC" fork="true" classpathref="cp" failonerror="true">
             <arg value="-d" />
             <arg value="${tmp}" />
             <arg value="-v" />