Categories
Development Java Linux

SAPJCO 2

Problem

We have a very, very old application that needs to be migrated into AWS. So we copied all files into AWS EC2 instance and tried to start the application. After fixing a lot of minor problems we faced a tough challenge with a SAPJCO RFC Call.

The Exception message was something like this:

Exception in thread "main" java.lang.ExceptionInInitializerError: JCO.classInitialize(): Could not load middleware layer 'com.sap.mw.jco.rfc.MiddlewareRFC'
JCO.nativeInit(): Could not initialize dynamic link library sapjcorfc [sapjcorfc (Not found in java.library.path)]. java.library.path [/usr/lib/jvm/java-1.6.0-ibm.x86_64/jre/lib/amd64/default:/usr/lib/jvm/java-1.6.0-ibm.x86_64/jre/lib/amd64:/usr/lib]
        at com.sap.mw.jco.JCO.<clinit>(JCO.java:871)
        at java.lang.J9VMInternals.initializeImpl(Native Method)
        at java.lang.J9VMInternals.initialize(J9VMInternals.java:199)

I guess, with a JCO Version 3 we would not have much trouble, but in this ancient application JCO Version 2 is used and we cannot update to Version 3 without a huge efford. In other projects I had the luck that I could migrate to Version.

The application is running on a Linux system. But belive me: it would have been much harder on a Windows machine.

Analysis

To find the cause of the problem I wrote the simpliest JCO Test Programm I can image:

import com.sap.mw.jco.JCO;

public class TestMain {

    public static void main(String[] args) {
        System.out.println(JCO.getVersion());
    }

}

My analysis programm structure:

app
├─ JCo/
│  ├─ librfccm.so
│  ├─ libsapjcorfc.so
│  ├─ sapjco.jar
├─ TestMain.java

Compile from command line:

javac -cp ".:/app/JCo/sapjco.jar" TestMain.java

Run from command line:

java -cp ".:/app/JCo/sapjco.jar" TestMain

That gave me another error:

Exception in thread "main" java.lang.ExceptionInInitializerError: JCO.classInitialize(): Could not load middleware layer 'com.sap.mw.jco.rfc.MiddlewareRFC'
JCO.nativeInit(): Could not initialize dynamic link library sapjcorfc [/app/JCo/libsapjcorfc.so: librfccm.so: cannot open shared object file: No such file or directory]. java.library.path [/app/JCo]
        at com.sap.mw.jco.JCO.<clinit>(JCO.java:871)
        at TestMain.main(TestMain.java:11)

Need to set an environment property first:

export LD_LIBRARY_PATH=/app/JCo

Run command line to start programm again and got another error:

Exception in thread "main" java.lang.ExceptionInInitializerError: JCO.classInitialize(): Could not load middleware layer 'com.sap.mw.jco.rfc.MiddlewareRFC'
JCO.nativeInit(): Could not initialize dynamic link library sapjcorfc [/app/JCo/libsapjcorfc.so: libstdc++.so.5: cannot open shared object file: No such file or directory]. java.library.path [/app/JCo]
        at com.sap.mw.jco.JCO.<clinit>(JCO.java:871)
        at TestMain.main(TestMain.java:11)

The interesting part of the error message:

Could not initialize dynamic link library sapjcorfc [/app/JCo/libsapjcorfc.so: libstdc++.so.5

Solution

We need the libstdc++.so.5 library, but installed is libstdc++.so.6

To get libstdc++.so.5 we installed package compat-libstdc++-33-3.2.3-66.x86_64:

yum install compat-libstdc++-33-3.2.3-66.x86_64

## to be honest, I am not exactly 100% sure, what I did in my investigations, so the command may be a little differend, ex:
# yum install compat-libstdc++-33-3
# yum install compat-libstdc++-33
# yum install compat-libstdc++-33 libstdc++.so.5

Test

Run from command line:

java -cp ".:/app/JCo/sapjco.jar" TestMain

That gave me no error, but SAPJCo Version number.:

2.1.10 (2011-05-10)

Finally it worked 😎

Anekdotum

Quote from an StackOverflow post from 2010:

libstdc++.so.5 is a very old version of the standard c++ library.

Some Analysis Details

Writing this article is giving me the feeling, that this was all super easy. But in reality it was a real pain in the allerwertesten.

To isolate the source of the problem, I did not only write the small Java (JCO.getVersion) application, I also set up a Docker environment.

One challenge was to find a useful Docker image to start from. I started with an OpenJDK Image that was already deprecated. Deprecated was not the problem, but I could not install libstdc++.so.5.

Next I tried to use the newer, undeprecated Eclipse-Temurin Image. But still could not install libstdc++.so.5

So I finally ended in a Debian Image and self installed Java where I was able to install libstdc++5.

FROM debian:bookworm-slim
 RUN apt-get update && apt-get install -y locales openjdk-11-jdk libstdc++5 \
     && rm -rf /var/lib/apt/lists/* \
     && localedef -i de_DE -c -f UTF-8 -A /usr/share/locale/locale.alias de_DE.UTF-8
 ENV LANG de_DE.utf8

COPY ./JCo/* /app/JCo/
COPY TestMain.java /app
WORKDIR /app
 ENV LD_LIBRARY_PATH=/app/JCo
 
 RUN javac -cp ".:/app/JCo/sapjco.jar" TestMain.java 

 CMD ["java", "-cp", ".:/app/JCo/sapjco.jar", "-Djava.library.path=/app/JCo", "TestMain"]

Note:

The locale might not be neccessary.
The “-Djava.library.path=/app/JCo” Parameter is not neccessary. But I leave it as an example, how one can use it.

Build and start the app:

docker build -t my-java-app .
docker run -it --rm --name my-running-app my-java-app
2.1.10 (2011-05-10)

Work in container

To work in the running container:

docker exec -it my-running-app /bin/sh

But there is one problem: You can only interact with a running container. But the TestMain-Programm is executed and immediately closed.

So I wrote another Test Programm, that keeps running, so I can enter the running container and test stuff (install packages, compile Java programm, etc.):

import java.io.BufferedReader;
import java.io.InputStreamReader;

import com.sap.mw.jco.JCO;

public class TestMain {

    public static void main(String[] args) {
        System.out.println("Hello World");
        //System.out.println("JCO Version: " + JCO.getVersion());

        while (true) {
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            System.out.println("Enter Input : ");
            try {
                String s = br.readLine();
                System.out.println(s);
            }catch(Exception e) {
                System.out.println(e);
            }
        }
        
    }

}
Categories
Linux

Jira – Login not working

Problem

Login into JIRA not working. JIRA is connected to LDAP.

Analysis

less /app/jira/jira/logs/catalina.out

[...]
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
[...]
less /app/jira/jira/bin/setenv.sh 

[...]
# DO NOT remove the following line
JAVA_HOME="/app/jira/jira/jre/"; export JAVA_HOME
[...]
ls -lisah /app/jira/jira/jre/lib/security/

[...]
134994220 116K -rw-rw-r--.  1 jira myusers 113K Jun 28  2019 cacerts
[...]
keytool -list -v -keystore /app/jira/jira/jre/lib/security/cacerts
Enter keystore password: <Just hit RETURN>

[...]
lots of certificates
[...]

keytool -list -v -keystore /app/jira/jira/jre/lib/security/cacerts -alias ldap.services.mycompany
--> Shows LDAP Certificate Details

Fix the Problem

Get LDAP SSL Cerificate and put it into Keystore:

openssl s_client -connect ldap.services.mycompany:636 < /dev/null | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > /tmp/ldap-sslcert.pem
/app/jira/jira/jre/bin/keytool -import -keystore /app/jira/jira/jre/lib/security/cacerts -file /tmp/ldap-sslcert.pem -alias ldap.services.mycompany
Enter keystore password: changeit
keytool error: java.lang.Exception: Certificate not imported, alias <ldap.services.mycompany> already exists

keytool -delete -keystore /app/jira/jira/jre/lib/security/cacerts -alias ldap.services.mycompany
Enter keystore password: changeit

/app/jira/jira/jre/bin/keytool -import -keystore /app/jira/jira/jre/lib/security/cacerts -file /tmp/ldap-sslcert.pem -alias ldap.services.mycompany
Enter keystore password: changeit
Trust this certificate? [no]:  yes
Certificate was added to keystore

Restart Jira:

systemctl start jira

###########
## Restart of Jira takes very long, wait for 10 minutes
###########

Test

Go to JIRA Login Page and login.
It is working again.