spawn java.exe on Windows not working

[rgl]

I'm trying to spawn a java application on Windows, but its not working even with an hello world created like:

  cat<<"EOF"> Program.java
public class Program {
  public static void main(String[] args) {
    System.out.println("Hello, World");
  }
}
EOF

  javac Program.java
  jar -cfe Program.jar Program Program.class
  java -jar Program.jar

The node script is:

var frida = require("frida");
var which = require("which");

const JAVA_PATH = which.sync("java");

frida
  .spawn([JAVA_PATH, "-jar", "Program.jar"])
  .then(function(pid) {
    console.log('spawned:', pid);
    // This is where you could attach (see below) and instrument APIs before you call resume()
    return frida.resume(pid);
  })
  .then(function() {
    console.log('resumed');
  })
  .catch(function(error) {
    console.log('error:', error.message);
  });

It will error out with:

spawned: 5784
resumed
Error: Could not find or load main class '-jar'

[oleavr]

Interesting. Does it work with any other applications? Did you try this use-case with the python binding by any chance? (I'm curious if it's a frida-node bug or deeper in the stack.)

[rgl]

I've tried with cat, echo, just java.exe (without arguments) and it works. But, it seems something odd happens when arguments are passed to java.exe.

I didn't try with python. I'll try it later.

[oleavr]

Ok! I wonder if there's something wrong with how we construct the argument list.

[rgl]

it has the same issue with python:

import frida
import os

# NB python 3.3+ already has a shutil.which function. we somewhat emulate it here.
def which(binary):
    extensions = os.getenv("PATHEXT", "").split(os.pathsep)
    for p in os.environ["PATH"].split(os.pathsep):
        path = os.path.join(p, binary)
        for extension in extensions:
            p = os.path.abspath(path + extension)
            if os.path.isfile(p) and os.access(p, os.X_OK):
                return p
    return None

JAVA_PATH = which("java")

args = [JAVA_PATH, "-jar", "Program.jar"]

# this works fine:
#os.spawnv(os.P_WAIT, JAVA_PATH, args)

pid = frida.spawn(args)
frida.resume(pid)

EDIT I've added the os.spawnv call.

[oleavr]

Aha, nice. Clearly a bug in frida-core then. I'll have a look at it before the upcoming release. Thanks!

[oleavr]

Fixed by frida/frida-core@2ff867f. Thanks for reporting!