Symbol Address (windbg + Javascript)

Test.js

"use strict;"
//
// Test.js
//
// Usage:
//
//   .load jsprovider.dll
//   .scriptload Test.js
//   dx Debugger.State.Scripts.Test.Contents.Test(0x1)
//
function exec_command(cmd_str)
{
    return host.namespace.Debugger.Utility.Control.ExecuteCommand(cmd_str);
}

function gsa(sym)
{
    return host.evaluateExpression("(unsigned __int64)(&" + sym + ")");
}

/* Get Symbol Address
Args:
    - sym_module (string): name of the module in which the symbol lies.
    - sym_name (string): name of the symbol for which to get the address
Returns:
    - The address of the symbol (if the symbol exists), otherwise the function returns null.
*/
function get_symbol_address(sym_module, sym_name)
{
    // basic input check.
    if(!sym_module || !sym_name){
        host.diagnostics.debugLog("get_symbol_address: sym_module or sym_name can't be empty.\n");
        return null;
    }

    // build the command
    // e.g. "x nt!ObTypeIndexTable"
    command = "x /0 " + sym_module + "!" + sym_name;
    // get the command result; e.g "fffff803`e8ae9b70"
    result = exec_command(command);
    addr_string = result.First();
    //host.diagnostics.debugLog("len: ", addr_string.length, " ; v:", addr_string,"\n");
    // we have a string longer than 18 chars if the symbol couldn't be resolved.
    if (addr_string.startsWith(" ") || addr_string.length > 18){
        return null;
    }
    // get the substring
    // note: passing the address string directly doesn't work... we need to remove the last char.
    addr_string = addr_string.substr(0, addr_string.length - 1);
    // convert to int64
    addr = host.parseInt64(addr_string , 16);
    return addr;
}

function Test(devObjParam) {

    // Get easy access to the debug output method
    var dbgOutput = host.diagnostics.debugLog;

    // ok!
    addr = host.getModuleSymbolAddress('ntdll', 'RtlAllocateHeap');
    dbgOutput("addr: ", addr, "\n");

    // ok!
    addr = host.getModuleSymbolAddress('nt', 'NtQueryInformationToken');
    dbgOutput("addr: ", addr, "\n");

    // KO :(( doesn't work
    //addr = host.getModuleSymbolAddress('nt', 'ObTypeIndexTable')
    //dbgOutput("addr: ", addr, "\n");

    // KO :(( doesn't work
    //addr = gsa("nt!NtQueryInformationToken")
    //dbgOutput("addr: ", addr, "\n");

    // OK!
    addr = get_symbol_address("nt", "ObTypeIndexTable");
    dbgOutput("nt!ObTypeIndexTable: ", addr, "\n");

    addr = get_symbol_address("ntfs", "NtfsData");
    dbgOutput("ntfs!NtfsData: ", addr, "\n");

    addr = get_symbol_address("nt", "NtQueryInformationToken");
    dbgOutput("nt!NtQueryInformationToken: ", addr, "\n");

    addr = get_symbol_address("foo", "bar");
    dbgOutput("foo!Bar: ", addr, "\n");

    addr = get_symbol_address("", "bar");
    dbgOutput("!Bar: ", addr, "\n");
}