Add qz:steal support (qzind#849)

Add support for shutting down another instance's websocket

src/qz/common/AboutInfo.java

@@ -143,6 +143,7 @@ public static String getPreferredHostname() {
     }
 
     public static Version findLatestVersion() {
+        log.trace("Looking for newer versions of {} online", Constants.ABOUT_TITLE);
         try {
             URL api = new URL(Constants.VERSION_CHECK_URL);
             BufferedReader br = new BufferedReader(new InputStreamReader(api.openStream()));
@@ -158,14 +159,14 @@ public static Version findLatestVersion() {
                 JSONObject versionData = versions.getJSONObject(i);
                 if(versionData.getString("target_commitish").equals("master")) {
                     Version latestVersion = Version.valueOf(versionData.getString("name"));
-                    log.trace("Found latest version: {}", latestVersion);
+                    log.trace("Found latest version of {} online: {}", Constants.ABOUT_TITLE, latestVersion);
                     return latestVersion;
                 }
             }
-            log.error("Failed to get latest version info");
+            throw new Exception("Could not find valid json version information online.");
         }
         catch(Exception e) {
-            log.error("Failed to get latest version info", e);
+            log.error("Failed to get latest version of {} online", Constants.ABOUT_TITLE, e);
         }
 
         return Constants.VERSION;

src/qz/common/Constants.java

@@ -5,6 +5,8 @@
 
 import java.awt.*;
 
+import static qz.ws.SingleInstanceChecker.STEAL_WEBSOCKET_PROPERTY;
+
 /**
  * Created by robert on 7/9/2014.
  */
@@ -23,7 +25,7 @@ public class Constants {
     public static final String LOG_FILE = "debug";
     public static final String PROPS_FILE = "qz-tray"; // .properties extension is assumed
     public static final String PREFS_FILE = "prefs"; // .properties extension is assumed
-    public static final String[] PERSIST_PROPS = { "file.whitelist", "file.allow", "networking.hostname", "networking.port" };
+    public static final String[] PERSIST_PROPS = {"file.whitelist", "file.allow", "networking.hostname", "networking.port", STEAL_WEBSOCKET_PROPERTY };
     public static final String AUTOSTART_FILE = ".autostart";
     public static final String DATA_DIR = "qz";
     public static final int LOG_SIZE = 524288;

src/qz/installer/MacInstaller.java

@@ -66,8 +66,8 @@ public String getDestination() {
     public Installer addSystemSettings() {
         // Chrome protocol handler
         String plist = "/Library/Preferences/com.google.Chrome.plist";
-        if(ShellUtilities.execute(new String[] { "/usr/bin/defaults", "write", plist }, new String[] { "qz://*" }).isEmpty()) {
-            ShellUtilities.execute("/usr/bin/defaults", "write", plist, "URLWhitelist", "-array-add", "qz://*");
+        if(ShellUtilities.execute(new String[] { "/usr/bin/defaults", "write", plist }, new String[] {DATA_DIR + "://*" }).isEmpty()) {
+            ShellUtilities.execute("/usr/bin/defaults", "write", plist, "URLWhitelist", "-array-add", DATA_DIR +"://*");
         }
         return this;
     }

src/qz/installer/TaskKiller.java

@@ -33,7 +33,7 @@ public static boolean killAll() {
 
         ArrayList<String> javaProcs;
         String[] trayProcs;
-        int selfProc;
+        int selfProc = SystemUtilities.getProcessId();
         String[] killCmd;
         // Disable service until reboot
         if(SystemUtilities.isMac()) {
@@ -43,12 +43,10 @@ public static boolean killAll() {
             // Windows may be running under javaw.exe (normal) or java.exe (terminal)
             javaProcs = AppLocator.getInstance().getPids("java.exe", "javaw.exe");
             trayProcs = ShellUtilities.executeRaw(TRAY_PID_QUERY_WIN32).split("\\s*\\r?\\n");
-            selfProc = Kernel32.INSTANCE.GetCurrentProcessId();
             killCmd = KILL_PID_CMD_WIN32;
         } else {
             javaProcs = AppLocator.getInstance().getPids( "java");
             trayProcs = ShellUtilities.executeRaw(TRAY_PID_QUERY_POSIX).split("\\s*\\r?\\n");
-            selfProc = MacUtilities.getProcessID(); // Works for Linux too
             killCmd = KILL_PID_CMD_POSIX;
         }
         if (!javaProcs.isEmpty()) {

src/qz/installer/WindowsInstaller.java

@@ -62,6 +62,8 @@ public Installer removeLegacyStartup() {
 
     public Installer addAppLauncher() {
         try {
+            // Delete old 2.0 launcher
+            FileUtils.deleteQuietly(new File(COMMON_START_MENU + File.separator + "Programs" + File.separator + ABOUT_TITLE + ".lnk"));
             Path loc = Paths.get(COMMON_START_MENU.toString(), "Programs", ABOUT_TITLE);
             loc.toFile().mkdirs();
             String lnk = loc + File.separator + ABOUT_TITLE + ".lnk";

src/qz/installer/certificate/WindowsCertificateInstaller.java

@@ -195,7 +195,7 @@ interface Crypt32 extends StdCallLibrary {
         int CERT_FIND_SUBJECT_STR = 524295;
         int CERT_FIND_SHA1_HASH = 65536;
 
-        Crypt32 INSTANCE = Native.loadLibrary("Crypt32", Crypt32.class, W32APIOptions.DEFAULT_OPTIONS);
+        Crypt32 INSTANCE = Native.load("Crypt32", Crypt32.class, W32APIOptions.DEFAULT_OPTIONS);
 
         WinCrypt.HCERTSTORE CertOpenStore(int lpszStoreProvider, int dwMsgAndCertEncodingType, Pointer hCryptProv, int dwFlags, String pvPara);
         boolean CertCloseStore(WinCrypt.HCERTSTORE hCertStore, int dwFlags);

src/qz/installer/certificate/firefox/locator/MacAppLocator.java

@@ -158,7 +158,7 @@ private static Path getExePath(String appPath) {
     }
 
     private interface SystemB extends Library {
-        SystemB INSTANCE = Native.loadLibrary("System", SystemB.class);
+        SystemB INSTANCE = Native.load("System", SystemB.class);
         int PROC_ALL_PIDS = 1;
         int PROC_PIDPATHINFO_MAXSIZE = 1024 * 4;
         int sysctlbyname(String name, Pointer oldp, IntByReference oldlenp, Pointer newp, int newlen);

src/qz/printer/status/Cups.java

@@ -7,7 +7,7 @@
  */
 public interface Cups extends Library {
 
-    Cups INSTANCE = Native.loadLibrary("cups", Cups.class);
+    Cups INSTANCE = Native.load("cups", Cups.class);
 
     /**
      * Static class to facilitate readability of values

src/qz/ui/BasicDialog.java

@@ -176,7 +176,7 @@ public void setVisible(boolean b) {
         // fix window focus on macOS
         if (SystemUtilities.isMac() && !GraphicsEnvironment.isHeadless()) {
             ShellUtilities.executeAppleScript("tell application \"System Events\" \n" +
-                                                      "set frontmost of every process whose unix id is " + MacUtilities.getProcessID() + " to true \n" +
+                                                      "set frontmost of every process whose unix id is " + SystemUtilities.getProcessId() + " to true \n" +
                                                       "end tell");
         }
         super.setVisible(b);

src/qz/utils/ArgValue.java

@@ -31,6 +31,8 @@ public enum ArgValue {
     // Options
     AUTOSTART(OPTION,"Read and honor any autostart preferences before launching.", null,
               "--honorautostart", "-A"),
+    STEAL(OPTION, "Ask other running instance to stop so that this instance can take precedence.", null,
+          "--steal", Constants.DATA_DIR + ":steal"),
     HEADLESS(OPTION, "Force startup \"headless\" without graphical interface or interactive components.", null,
              "--headless"),
 

src/qz/utils/GtkUtilities.java

@@ -98,7 +98,7 @@ private interface GTK extends Library {
     }
 
     private interface GTK3 extends GTK {
-        GTK3 INSTANCE = Native.loadLibrary("gtk-3", GTK3.class);
+        GTK3 INSTANCE = Native.load("gtk-3", GTK3.class);
 
         // Gtk 3.0+
         int gtk_get_minor_version ();
@@ -112,7 +112,7 @@ private interface GTK3 extends GTK {
     }
 
     private interface GTK2 extends GTK {
-        GTK2 INSTANCE = Native.loadLibrary("gtk-x11-2.0", GTK2.class);
+        GTK2 INSTANCE = Native.load("gtk-x11-2.0", GTK2.class);
 
         // Gtk 2.1-3.0
         double gdk_screen_get_resolution(Pointer screen);

src/qz/utils/MacUtilities.java

@@ -149,7 +149,7 @@ public static int getScaleFactor() {
         return 1;
     }
 
-    public static int getProcessID() {
+    static int getProcessId() {
         if(pid == null) {
             try {
                 pid = CLibrary.INSTANCE.getpid();
@@ -163,7 +163,7 @@ public static int getProcessID() {
     }
 
     private interface CLibrary extends Library {
-        CLibrary INSTANCE = (CLibrary) Native.loadLibrary("c", CLibrary.class);
+        CLibrary INSTANCE = Native.load("c", CLibrary.class);
         int getpid ();
     }
 

src/qz/utils/SystemUtilities.java

@@ -12,6 +12,7 @@
 
 import com.github.zafarkhaja.semver.Version;
 import org.apache.commons.lang3.StringUtils;
+import org.apache.commons.ssl.Base64;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import qz.common.Constants;
@@ -22,12 +23,15 @@
 import java.io.File;
 import java.io.IOException;
 import java.net.URLDecoder;
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.Locale;
+import java.util.Random;
 import java.util.TimeZone;
 
 import static com.sun.jna.platform.win32.WinReg.*;
@@ -111,6 +115,13 @@ public static boolean isAdmin() {
         }
     }
 
+    public static int getProcessId() {
+        if(isWindows()) {
+            return WindowsUtilities.getProcessId();
+        }
+        return MacUtilities.getProcessId(); // works for Linux too
+    }
+
     /**
      * Handle Java versioning nuances
      * To eventually be replaced with <code>java.lang.Runtime.Version</code> (JDK9+)
@@ -359,7 +370,7 @@ public static boolean prefersMaskTrayIcon() {
         if (Constants.MASK_TRAY_SUPPORTED) {
             if (SystemUtilities.isMac()) {
                 // Assume a pid of -1 is a broken JNA
-                return MacUtilities.getProcessID() != -1;
+                return MacUtilities.getProcessId() != -1;
             } else if (SystemUtilities.isWindows() && SystemUtilities.getOSVersion().getMajorVersion() >= 10) {
                 return true;
             }
@@ -584,4 +595,55 @@ public static void clearAlgorithms() {
             log.warn("Unable to apply JDK-8266929 patch.  Some algorithms may fail.", e);
         }
     }
+
+    /**
+     * A challenge which can only be calculated by an app installed and running on this machine
+     * Calculates two bytes:
+     * - First byte is a salted version of the timestamp of qz-tray.jar
+     * - Second byte is a throw-away byte
+     * - Bytes are converted to Base64 and returned as a String
+     */
+    public static String calculateSaltedChallenge() {
+        int salt = new Random().nextInt(9);
+        long salted = (calculateChallenge() * 10) + salt;
+        long obfuscated = salted * new Random().nextInt(9);
+        ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES * 2);
+        buffer.putLong(obfuscated);
+        buffer.putLong(0, salted);
+        return new String(Base64.encodeBase64(buffer.array(), false), StandardCharsets.UTF_8);
+    }
+
+    private static long calculateChallenge() {
+        if(getJarPath() != null) {
+            File jarFile = new File(getJarPath());
+            if (jarFile.exists()) {
+                return jarFile.lastModified();
+            }
+        }
+        return -1L; // Fallback when running from IDE
+    }
+
+    /**
+     * Decodes challenge string to see if it originated from this application
+     * - Base64 string is decoded into two bytes
+     * - First byte is unsalted
+     * - Second byte is ignored
+     * - If unsalted value of first byte matches the timestamp of qz-tray.jar, return true
+     * - If unsalted value doesn't match or if any exceptions occurred, we assume the message is invalid
+     */
+    public static boolean validateSaltedChallenge(String message) {
+        try {
+            log.info("Attempting to validating challenge: {}", message);
+            byte[] decoded = Base64.decodeBase64(message);
+            ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES * 2);
+            buffer.put(decoded);
+            buffer.flip();//need flip
+            long salted = buffer.getLong(0); // only first byte matters
+            long challenge = salted / 10L;
+            return challenge == calculateChallenge();
+        } catch(Exception ignore) {
+            log.warn("An exception occurred validating challenge: {}", message, ignore);
+        }
+        return false;
+    }
 }

src/qz/utils/WindowsUtilities.java

@@ -1,7 +1,9 @@
 package qz.utils;
 
 import com.github.zafarkhaja.semver.Version;
+import com.sun.jna.Native;
 import com.sun.jna.platform.win32.*;
+import com.sun.jna.win32.W32APIOptions;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import qz.common.Constants;
@@ -285,4 +287,13 @@ public static boolean elevatedFileCopy(Path source, Path destination) {
         String[] command = {"Start-Process", "powershell.exe", "-ArgumentList", args, "-Wait", "-Verb", "RunAs"};
         return ShellUtilities.execute("powershell.exe", "-command", String.join(" ", command));
     }
+
+    static int getProcessId() {
+        try {
+            return Kernel32.INSTANCE.GetCurrentProcessId();
+        } catch(UnsatisfiedLinkError | NoClassDefFoundError e) {
+            log.warn("Could not obtain process ID.  This usually means JNA isn't working.  Returning -1.");
+        }
+        return -1;
+    }
 }

src/qz/ws/PrintSocketClient.java

@@ -5,6 +5,7 @@
 import org.codehaus.jettison.json.JSONArray;
 import org.codehaus.jettison.json.JSONException;
 import org.codehaus.jettison.json.JSONObject;
+import org.eclipse.jetty.server.Server;
 import org.eclipse.jetty.websocket.api.Session;
 import org.eclipse.jetty.websocket.api.WebSocketException;
 import org.eclipse.jetty.websocket.api.annotations.*;
@@ -46,6 +47,11 @@ public class PrintSocketClient {
     //websocket port -> Connection
     private static final HashMap<Integer,SocketConnection> openConnections = new HashMap<>();
 
+    private Server server;
+
+    public PrintSocketClient(Server server) {
+        this.server = server;
+    }
 
     @OnWebSocketConnect
     public void onConnect(Session session) {
@@ -588,7 +594,21 @@ private void processMessage(Session session, JSONObject json, SocketConnection c
             case GET_VERSION:
                 sendResult(session, UID, Constants.VERSION);
                 break;
-
+            case WEBSOCKET_STOP:
+                log.info("Another instance of {} is asking this to close", Constants.ABOUT_TITLE);
+                String challenge = json.optString("challenge", "");
+                if(SystemUtilities.validateSaltedChallenge(challenge)) {
+                    log.info("Challenge validated: {}, honoring shutdown request", challenge);
+
+                    session.close(SingleInstanceChecker.REQUEST_INSTANCE_TAKEOVER);
+                    try {
+                        server.stop();
+                    } catch(Exception ignore) {}
+                    trayManager.exit(0);
+                } else {
+                    log.warn("A valid challenge was not provided: {}, ignoring request to close", challenge);
+                }
+                break;
             case INVALID:
             default:
                 sendError(session, UID, "Invalid function call: " + json.optString("call", "NONE"));

src/qz/ws/PrintSocketServer.java

@@ -43,6 +43,9 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import static qz.utils.ArgParser.ExitStatus.SUCCESS;
+import static qz.utils.ArgValue.STEAL;
+
 /**
  * Created by robert on 9/9/2014.
  */
@@ -63,13 +66,14 @@ public class PrintSocketServer {
 
     private static boolean forceHeadless;
 
-
     public static void main(String[] args) {
         ArgParser parser = new ArgParser(args);
         if (parser.intercept()) {
             System.exit(parser.getExitCode());
         }
         forceHeadless = parser.hasFlag(ArgValue.HEADLESS);
+        SingleInstanceChecker.stealWebsocket = parser.hasFlag(STEAL);
+
         log.info(Constants.ABOUT_TITLE + " version: {}", Constants.VERSION);
         log.info(Constants.ABOUT_TITLE + " vendor: {}", Constants.ABOUT_COMPANY);
         log.info("Java version: {}", Constants.JAVA_VERSION.toString());
@@ -89,6 +93,7 @@ public static void main(String[] args) {
 
         // Load overridable preferences set in qz-tray.properties file
         NetworkUtilities.setPreferences(certificateManager.getProperties());
+        SingleInstanceChecker.setPreferences(certificateManager.getProperties());
 
         // Linux needs the cert installed in user-space on every launch for Chrome SSL to work
         if (!SystemUtilities.isWindows() && !SystemUtilities.isMac()) {
@@ -151,7 +156,7 @@ public static void runServer() {
 
                 // Handle WebSocket connections
                 WebSocketUpgradeFilter filter = WebSocketUpgradeFilter.configure(context);
-                filter.addMapping(new ServletPathSpec("/"), (req, resp) -> new PrintSocketClient());
+                filter.addMapping(new ServletPathSpec("/"), (req, resp) -> new PrintSocketClient(server));
                 filter.getFactory().getPolicy().setMaxTextMessageSize(MAX_MESSAGE_SIZE);
 
                 // Handle HTTP landing page