LicenseManager.java

/* ==================================================================   
 * Created [2009-4-27 下午11:32:55] by Jon.King 
 * ==================================================================  
 * TSS 
 * ================================================================== 
 * mailTo:jinpujun@hotmail.com
 * Copyright (c) Jon.King, 2009-2012 
 * ================================================================== 
*/

package com.jinhe.tss.core.common.license;

import java.io.File;
import java.security.KeyFactory;
import java.security.Signature;
import java.security.spec.X509EncodedKeySpec;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.jinhe.tss.core.util.FileHelper;
import com.jinhe.tss.core.util.EasyUtils;

/** 
 * <p> LicenseManager.java </p> 
 * 
 * 1、应用程序可以创建以及验证绑定给用户、系统等实体的license。
 * 2、licenses可以是永久性的或者临时性的（在某个特定时期内有效）
 * 3、共享应用程序可以配置试用期licenses
 * 4、licenses的验证由JAVA Security API提供的数字签名机制来实现。通过生成公钥/私钥对来分别对licenses进行签名和校验。
 * 5、license安装模块需要用特殊机制对其进行保护，以防被反编译轻易破解。可以使用java代码编译混淆器、自定义类装载器来实现。
 * 
 */
public final class LicenseManager {

    private final Log log = LogFactory.getLog(getClass());
    
    private static LicenseManager instance = new LicenseManager();
    private LicenseManager(){ }
    public static synchronized LicenseManager getInstance() {
        return instance;
    }
    
    private List<License> licenses;

    public void loadLicenses() {
        if(licenses != null)
            return;
        
        licenses = new ArrayList<License>();
        String files[] = new File(LicenseFactory.LICENSE_DIR).list();
        for(int i = 0; i < files.length; i++){
            String filename = files[i];
            File file = new File(LicenseFactory.LICENSE_DIR, filename);
            if(file.isDirectory() || !filename.startsWith("cpu") || !filename.endsWith(".license"))
                continue;
            
            try {
                License license = License.fromConfigFile(filename);
                
                Date expiresDate = license.getExpiresDate();
                if(expiresDate != null && expiresDate.getTime() < System.currentTimeMillis()) {
                    log.error("license文件 \"" + file.getName() + "\" 已经过期.");
                    continue; 
                }
                if(!validate(license)) {
                    log.error("license文件 \"" + file.getName() + "\" 不合法.");
                    continue; 
                }
                licenses.add(license);
            } catch(Exception e) {
                log.error(e);
            }
        }

        if(licenses.isEmpty()){
            log.error("找不到合法的许可文件（license）.");
        }
        return;
    }
    
    /**
     * 重新载入licenses
     */
    public void reloadLicenses() {
        if(licenses != null)
            licenses.clear();
        licenses = null;
        loadLicenses();
    }

    /**
     * 验证产品和版本号是否和license中信息匹配
     * @param product
     * @param version
     * @return
     */
    public boolean validateLicense(String product, String version) {
        loadLicenses();
        if(!licenses.isEmpty()) {
            int needsVersion = Integer.parseInt(version.substring(0, 1));
            for(int i = 0; i < licenses.size(); i++) {
                License license = (License)licenses.get(i);
                int hasVersion = Integer.parseInt(license.getVersion().substring(0, 1));
                if(license.getProduct().equals(product) && hasVersion >= needsVersion)
                    return true;
            }
        }
        return false;
    }

    /**
     * 获取license的类型。
     * 
     * @param product
     * @param version
     * @return
     */
    public String getLicenseType(String product, String version) {
        loadLicenses();
        if(!licenses.isEmpty()) {
            int needsVersion = Integer.parseInt(version.substring(0, 1));
            for(int i = 0; i < licenses.size(); i++) {
                License license = (License)licenses.get(i);
                int hasVersion = Integer.parseInt(license.getVersion().substring(0, 1));
                if(license.getProduct().equals(product) && hasVersion >= needsVersion)
                    return license.getLicenseType().name;
            }
        }
        return null;
    }

    /**
     * 验证license是否合法。
     * 首先验证Mac地址是否有改变，有的话则非法。（防止用户自由拷贝软件）。
     * 然后根据公钥验证签名是否合法。
     * 
     * @param license
     * @return
     * @throws Exception
     */
    boolean validate(License license) throws Exception {
        String macAddress = license.getMacAddress();
        if(macAddress != null && macAddress.length() > 0) {
            String curMacAddress = MacAddressUtil.getMacAddress();
            if(!macAddress.equals(curMacAddress))
                return false;
        }
        String publicKey = FileHelper.readFile(new File(LicenseFactory.PUBLIC_KEY_FILE)).trim();

        X509EncodedKeySpec pubKeySpec = new X509EncodedKeySpec(EasyUtils.decodeHex(publicKey));
        KeyFactory keyFactory = KeyFactory.getInstance("DSA");
        java.security.PublicKey pubKey = keyFactory.generatePublic(pubKeySpec);
        
        Signature sig = Signature.getInstance("DSA");
        sig.initVerify(pubKey);
        sig.update(license.getFingerprint());
        return sig.verify(EasyUtils.decodeHex(license.getLicenseSignature()));
    }
}