aeron-client/src/main/java/io/aeron/CommonContext.java
public static boolean isDriverActive(
        final File directory, final long driverTimeoutMs, final Consumer<String> logger)
    {
        final File cncFile = new File(directory, CncFileDescriptor.CNC_FILE);

        if (cncFile.exists() && cncFile.length() > 0)
        {
            logger.accept("INFO: Aeron CnC file exists: " + cncFile);

            final MappedByteBuffer cncByteBuffer = IoUtil.mapExistingFile(cncFile, "CnC file");
            try
            {
                return isDriverActive(driverTimeoutMs, logger, cncByteBuffer);
            }
            finally
            {
                IoUtil.unmap(cncByteBuffer);
            }
        }

        return false;
    }
public static boolean isDriverActive(
        final File directory, final long driverTimeoutMs, final Consumer<String> logger)
    {
        final File cncFile = new File(directory, CncFileDescriptor.CNC_FILE);

        if (cncFile.exists() && cncFile.length() > 0)
        {
            logger.accept("INFO: Aeron CnC file exists: " + cncFile);

            final MappedByteBuffer cncByteBuffer = IoUtil.mapExistingFile(cncFile, "CnC file");
            try
            {
                return isDriverActive(driverTimeoutMs, logger, cncByteBuffer);
            }
            finally
            {
                IoUtil.unmap(cncByteBuffer);
            }
        }

        return false;
    }
Is a media driver active in the given directory?

@param directory       to check
@param driverTimeoutMs for the driver liveness check.
@param logger          for feedback as liveness checked.
@return true if a driver is active or false if not.