Bug#966338: tomcat9: overrriding JAVA_HOME in /e/d/tomcat9 has changed

Mon Jul 27 07:23:23 BST 2020

Package: tomcat9
Version: 9.0.31-1~deb10u2
Severity: normal
Tags: patch

I'm reporting a change in behaviour from tomcat8 and I'm not sure what the
correct fix is. While I'm reporting against the buster version, the issue
still seems to exist in current git (1ac6d044 Update changelog).

The gist is trying to override JAVA_HOME in the /etc/defaults/tomcat9 file
now _requires_ an export statement. This was not the case for tomcat8.

Gory details:

I found this on a machine upgraded from stretch to buster.
The old java version was the default and tomcat8 was still running:

% update-alternatives --display java
java - manual mode
  link best version is /usr/lib/jvm/java-11-openjdk-amd64/bin/java
  link currently points to /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java
  link java is /usr/bin/java
  slave java.1.gz is /usr/share/man/man1/java.1.gz
/usr/lib/jvm/java-11-openjdk-amd64/bin/java - priority 1111
  slave java.1.gz: /usr/lib/jvm/java-11-openjdk-amd64/man/man1/java.1.gz
/usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java - priority 1069
  slave java.1.gz: /usr/lib/jvm/java-8-openjdk-amd64/jre/man/man1/java.1.gz


When I tried to start tomcat9 under java 11,
I did made the usual change in /etc/default/tomcat9

  #JAVA_HOME=/usr/lib/jvm/java-8-openjdk
 +JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64

But when tomcat9 starts, it reports it is running under java 8
 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Server version name:   Apache Tomcat/9.0.31 (Debian)
 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Server built:          Jul 15 2020 11:43:33 UTC
 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Server version number: 9.0.31.0
 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log OS Name:               Linux
 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log OS Version:            4.19.0-9-amd64
 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Architecture:          amd64
 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Java Home:             /usr/lib/jvm/java-8-openjdk-amd64/jre
 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log JVM Version:           1.8.0_252-8u252-b09-1~deb9u1-b09
 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log JVM Vendor:            Oracle Corporation
 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_BASE:         /var/lib/tomcat9
 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_HOME:         /usr/share/tomcat9


This seems to be because there is no export of JAVA_HOME when it is overridden,
i.e. this configuration in /etc/default/tomcat9 works correctly:

  #JAVA_HOME=/usr/lib/jvm/java-8-openjdk
 +JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64
 +export JAVA_HOME

The 'export' was not necessary in tomcat8 because the init script takes
care of it

     81 # Look for the right JVM to use
     82 for jdir in $JDK_DIRS; do
     83     if [ -r "$jdir/bin/java" -a -z "${JAVA_HOME}" ]; then
     84         JAVA_HOME="$jdir"
     85     fi
     86 done
     87 export JAVA_HOME

Where the startup sequence loses track of a JAVA_HOME override is when
  /usr/libexec/tomcat9/tomcat-start.sh
execs into
  "/usr/share/tomcat9/bin/catalina.sh run"
and that script sources
   /usr/share/tomcat9/bin/setclasspath.sh

In that script this test fails and JAVA_HOME is set to /usr
     24 # Make sure prerequisite environment variables are set
     25 if [ -z "$JAVA_HOME" ] && [ -z "$JRE_HOME" ]; then
     26   if $darwin; then
...
     34   else
     35     JAVA_PATH=`which java 2>/dev/null`
     36     if [ "x$JAVA_PATH" != "x" ]; then
     37       JAVA_PATH=`dirname "$JAVA_PATH" 2>/dev/null`
     38       JRE_HOME=`dirname "$JAVA_PATH" 2>/dev/null`
     39     fi


The squence of events leading up to this is
systemd calls
  /usr/libexec/tomcat9/tomcat-start.sh
which sources
  /etc/default/tomcat9
and then sources
  /usr/libexec/tomcat9/tomcat-locate-java.sh

This script does the same job as the init script code above,
but the important difference is that it only exports JAVA_HOME
if it updates it; if JAVA_HOME is already set then the script
does not export it.

Before, that hunk of code exported JAVA_HOME unconditionally.

Then we exec into catalina.sh and the not-exported JAVA_HOME override is lost.


Possible fixes:

 * tweak the example override in /etc/default/tomcat9
   - #JAVA_HOME=/usr/lib/jvm/java-8-openjdk
   + #JAVA_HOME=/usr/lib/jvm/java-8-openjdk; export JAVA_HOME

 * unconditionally export JAVA_HOME

--- tomcat-locate-java.sh       2020-07-27 16:13:45.903064630 +1000
+++ tomcat-locate-java.sh.new   2020-07-27 16:14:09.283692229 +1000
@@ -40,10 +40,11 @@
             JAVA_HOME="$jdir"
         fi
     done
-    export JAVA_HOME
 fi

 if [ -z "$JAVA_HOME" ]; then
     echo "<2>No JDK or JRE found - Please set the JAVA_HOME variable or install the default-jdk package"
     exit 1
 fi
+
+export JAVA_HOME


Kind regards
Vince

-- System Information:
Debian Release: 10.4
  APT prefers stable
  APT policy: (990, 'stable'), (500, 'stable-debug')
Architecture: amd64 (x86_64)

Kernel: Linux 4.19.0-9-amd64 (SMP w/28 CPU cores)
Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8), LANGUAGE=en_AU:en (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages tomcat9 depends on:
ii  lsb-base        10.2019051400
ii  systemd         241-7~deb10u4
ii  tomcat9-common  9.0.31-1~deb10u2
ii  ucf             3.0038+nmu1

Versions of packages tomcat9 recommends:
pn  libtcnative-1  <none>

Versions of packages tomcat9 suggests:
pn  tomcat9-admin     <none>
pn  tomcat9-docs      <none>
pn  tomcat9-examples  <none>
pn  tomcat9-user      <none>

-- no debconf information

