CODEWITHSUNDEEP
javalinuxunix
abhishek
abhishek

Reputation: 817

How to set a unix dynamic library path (LD_LIBRARY_PATH) in Java?

I have a binary executable (no source code) which requires this command to be executed in the terminal - export LD_LIBRARY_PATH = "" to link to a library lbtiff.so.3 which I have in a directory. Only after I execute this export command, I can execute the binary, otherwise it gives an error - "error while loading shared libraries: libtiff.so.3...

Now, I want to execute this binary from my java code. But simply executing the export command in the runtime does not do anything and the "error while .." error still occurs when I execute the binary from Java. I guess setting the unix specific environment variable LD_LIBRARY_PATH might not be possible from Java - is there a way I can run my binary from Java and it is able to find the libraries? Here's my current code - 

Process p = Runtime.getRuntime().exec("bash -c export LD_LIBRARY_PATH=<lib path>");

p = Runtime.getRuntime().exec("<binary path>");

Upvotes: 2

Views: 21630

Answers (3)

Ian Roberts
Ian Roberts

Reputation: 122364

Rather than Runtime.exec, use ProcessBuilder. That will allow you to specify environment variables when you run the binary that requires them

ProcessBuilder pb = new ProcessBuilder("<binarypath>");
pb.environment().put("LD_LIBRARY_PATH", "<libPath>");
Process p = pb.start();

Your approach with two separate Runtime.exec calls will not work, because the environment settings you make in the first one only affect that particular Process, not subsequent processes started by a separate invocation of Runtime.exec.

Upvotes: 5

Philipp Wendler
Philipp Wendler

Reputation: 11433

See my answer to another question. The best way is to not use an external shell to set the environment variable (your code doesn't work because it will not set the variable globally, only for the bash process), but to set the variable from within Java. Much easier and it works (and on all platforms, regardless of which shell is installed).

Upvotes: 3

Alex
Alex

Reputation: 25613

On unix systems you can prepend the variable before executing the command

LD_LIBRARY_PATH=... foo args

Will execute the program foo with args using the modified LD_LIBRARY_PATH

Or you could take advantage of the subshell by using:

(export LD_LIBRARY_PATH=...; foo args)

Upvotes: 1

Related Questions