KARAF-4564 Can't start karaf using symbolic link

[adetalhouet]

When executing the karaf script, it gets the DIRNAME based on $0 which is the path used to start the script. This DIRNAME is then used to set the KARAF_HOME and multiple other KARAF_* env variables.
Using a symbolic link, you would have, for instance, usr/bin/karaf redirecting to /opt/opendaylight/bin/karaf. So $0 would be usr/bin and not /opt/opendaylight/bin so the locateHome function isn't setting the right path for the KARAF_HOME.

This ends up failing to start ODL with following
ERROR: Error: Could not find or load main class org.apache.karaf.main.Main

Signed-off-by: Alexis de Talhouët adetalhouet@inocybe.com

[adetalhouet]

The pull request isn't complete as it should take care of the .bat scripts a well. But I wasn't able to figure it out for the batch script.

[jbonofre]

Unfortunately, I don't think it's a good idea to use realpath as it's not available on most of Unix systems.
For instance, on Debian/Ubuntu, it requires:

$ sudo apt-get install realpath

Maybe readlink is more appropriate ?

[jbonofre]

Even better, we can test if readlink is available on the system, then use it, else fallback to the current behavior.

[adetalhouet]

Sure, would you like me to test it to make sure it solves the issue the same way?

On Jun 9, 2016, at 9:27 AM, Jean-Baptiste Onofré notifications@github.com wrote:

Unfortunately, I don't think it's a good idea to use realpath as it's not available on most of Unix systems.
For instance, on Debian/Ubuntu, it requires:

$ sudo apt-get install realpath
Maybe readlink is more appropriate ?

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[jbonofre]

That would be great ! Thanks !

[adetalhouet]

I confirm readlink is working fine with the three environments mentioned in the JIRA

[jbonofre]

As said in my previous comment, even if readlink is available by default on most of system, it's not necessarily the case. I would add a test to check if readlink command is available: if yes, then we use it for basedir, else we "fallback" to the current behavior.

For instance, something like type readlink and check if it returns 0 (readlink is found on the system) or 1 (readlink is not found on the system).

[adetalhouet]

So would this be more appropriate?

READLINK=`type readlink`
if [ "x$READLINK" = "x" ]; then
    REALNAME=$0
else
    REALNAME=`readlink "$0"`
fi

DIRNAME=`dirname "$REALNAME"`
PROGNAME=`basename "$REALNAME"`

But if readlink doesn't exist it will trigger a warning:
/usr/bin/karaf: line 19: type: readlink: not found

[jbonofre]

I would do more something like:

REALNAME=`readlink "$0"`
if [ $? != 0 ]; then
  REALNAME=$0
fi

[jbonofre]

I updated the PR with:

REALNAME=`readlink -e "$0" > /dev/null 2>&1`
if [ $? != 0 ]; then
    REALNAME=$0
fi
DIRNAME=`dirname "$REALNAME"`
PROGNAME=`basename "$REALNAME"`

It works fine. Rebasing and merging.

[adetalhouet]

@jbonofre Thank you for such a great support!

[jbonofre]

@adetalhouet you are welcome ! My pleasure !

[vorburger]

=> https://issues.apache.org/jira/browse/KARAF-4599