// Name: Update jvm.options file for an Avantra agent
// Type: Autoamtion step example-code ONLY (please adapt to your environment)
// Description: Update your linux-based agent config to include protection against CVE-2021-44228 - Log4j 2 Vulnerability
// Author: Avantra Support
// Date: Sat Dec 11 2021

// ASSUMPTIONS
// 1) Your agent is running under the systemd service avantra-agent
// 2) Your agent is correctly configured with the ability to restart itself e.g. sudo systemctl restart avantra-agent
// 3) Your install directory is set below

// ######### Variable and constant declarations

const agentInstallLocation = "/opt/avantra/agent/";
const log4j_disable = "log4j2.formatMsgNoLookups=true";
const agent_java_args = 'AGENT_JAVA_ARGS="';
const configFileLocation = agentInstallLocation + "cfg/jvm.options";
const agentRestartCommand = 'nohup bash -c "sleep 5 ;  sudo systemctl restart avantra-agent " &';

// ######### Functions

// ######### Check Execution Logic
// Get the contents of the current configuration file
var currentConfig = os.exec("cat " + configFileLocation);

// If we have managed to open the file then we can continue - otherwise we error out.
if(currentConfig.exitCode === 0){
    
    // Pull the file contents into a variable.
    var fileContents = currentConfig.out;
    
    // Search for the log4j2 disabling string
    // This way, if it's already present we can stop execution.
    var stringLocation = fileContents.indexOf(log4j_disable);
    
    // If the configuration is not already in place, we continue.
    if(stringLocation === -1){
        // Get the location of the "AGENT_JAVA_ARGS=" string so we know where to add the config.
        var location_of_java_args_wrapper = fileContents.indexOf(agent_java_args);

        // If we cannot locate the configuration within the file - we error out
        // You may adjust the code here if you want to add new config if it doesn't exist but that is your choice to make.
        if(location_of_java_args_wrapper === -1){
            check.message = 'Unable to find valid java configuration items in the file i.e. no AGENT_JAVA_ARGS="-Dx=y -Dy=z"';
        }

        // Next we get the location of the config flags within the AGENT_JAVA_ARGS="<this stuff in here>" string
        var location_of_start_of_existing_config = (location_of_java_args_wrapper + (agent_java_args.length));

        // Create a variable to house the new coniguration file contents.
        var result = "";

        // In case the config is not the first item in that file, we append all the stuff at the beginning to the output.
        if(location_of_java_args_wrapper > 0){
            result = fileContents.slice(0, location_of_java_args_wrapper);
        }
        // Build the new configuration file.
        var result = result + agent_java_args + "-D" + log4j_disable + " " + fileContents.slice(location_of_start_of_existing_config,fileContents.length);

        // Output the new configuration file contents to the file.
        os.exec("echo '" + result + "' > " + configFileLocation);

        // Now that the configuration is updated - we can trigger an agent restart
        os.exec(agentRestartCommand);
        check.message = "Configuration updated successfully and agent restart triggered.";

    // If the config is already in place then we throw and error to stop execution.
    } else {
        check.message = "JVM configuration already in place - no need to continue.";
    }
    
} else {
    check.message = "Unable to open config file at " + configFileLocation;
    check.status = WARNING;
}