diff --git a/xulrunner/stub/nsXULStub.cpp b/xulrunner/stub/nsXULStub.cpp
--- a/xulrunner/stub/nsXULStub.cpp
+++ b/xulrunner/stub/nsXULStub.cpp
@@ -107,16 +107,31 @@ static void Output(PRBool isError, const
 		      sizeof(wide_msg) / sizeof(wchar_t));

   MessageBoxW(NULL, wide_msg, L"XULRunner", flags);
 #else
   vfprintf(stderr, fmt, ap);
 #endif

   va_end(ap);
+}
+
+/**
+ * Return true if |arg| matches the given argument name.
+ */
+static PRBool IsArg(const char* arg, const char* s)
+{
+  if (*arg == '-')
+  {
+    if (*++arg == '-')
+      ++arg;
+    return !strcasecmp(arg, s);
+  }
+
+  return PR_FALSE;
 }

 class AutoAppData
 {
 public:
   AutoAppData(nsILocalFile* aINIFile) : mAppData(nsnull) {
     nsresult rv = XRE_CreateAppData(aINIFile, &mAppData);
     if (NS_FAILED(rv))
@@ -211,45 +226,71 @@ main(int argc, char **argv)
      // p.Path returns a pointer, so use strcpy to store path in iniPath
      strcpy(iniPath, p.Path());

 #else
   // on unix, there is no official way to get the path of the current binary.
   // instead of using the MOZILLA_FIVE_HOME hack, which doesn't scale to
   // multiple applications, we will try a series of techniques:
   //
-  // 1) use realpath() on argv[0], which works unless we're loaded from the
+  // 1) if -app is specified, use realpath on passed value in order to properly
+  //    hook the application.ini file to the stub logic.
+  // 2) use realpath() on argv[0], which works unless we're loaded from the
   //    PATH
-  // 2) manually walk through the PATH and look for ourself
-  // 3) give up
+  // 3) manually walk through the PATH and look for ourself
+  // 4) give up

+  const char *appDataFile = getenv("XUL_APP_FILE");
   struct stat fileStat;

-  if (!realpath(argv[0], iniPath) || stat(iniPath, &fileStat)) {
-    const char *path = getenv("PATH");
-    if (!path)
-      return 1;
+  if (!(appDataFile && *appDataFile)) {
+    if (argc > 1 && IsArg(argv[1], "app")) {
+      if (argc == 2) {
+        Output(PR_FALSE, "specify APP-FILE (optional)\n");
+        return 1;
+      }
+      argv[1] = argv[0];
+      ++argv;
+      --argc;

-    char *pathdup = strdup(path);
-    if (!pathdup)
-      return 1;
+      appDataFile = argv[1];
+      argv[1] = argv[0];
+      ++argv;
+      --argc;

-    PRBool found = PR_FALSE;
-    char *token = strtok(pathdup, ":");
-    while (token) {
-      sprintf(tmpPath, "%s/%s", token, argv[0]);
-      if (realpath(tmpPath, iniPath) && stat(iniPath, &fileStat) == 0) {
-        found = PR_TRUE;
-        break;
+      static char kAppEnv[MAXPATHLEN];
+      snprintf(kAppEnv, MAXPATHLEN, "%s", appDataFile);
+      setenv("XUL_APP_FILE", kAppEnv, 1);
+    }
+  }
+
+  if (!realpath(appDataFile, iniPath) || stat(iniPath, &fileStat)) {
+    if (!realpath(argv[0], iniPath) || stat(iniPath, &fileStat)) {
+      const char *path = getenv("PATH");
+      if (!path)
+        return 1;
+
+      char *pathdup = strdup(path);
+      if (!pathdup)
+        return 1;
+
+      PRBool found = PR_FALSE;
+      char *token = strtok(pathdup, ":");
+      while (token) {
+        sprintf(tmpPath, "%s/%s", token, argv[0]);
+        if (realpath(tmpPath, iniPath) && stat(iniPath, &fileStat) == 0) {
+          found = PR_TRUE;
+          break;
+        }
+        token = strtok(NULL, ":");
       }
-      token = strtok(NULL, ":");
+      free (pathdup);
+      if (!found)
+        return 1;
     }
-    free (pathdup);
-    if (!found)
-      return 1;
   }
 #endif

   lastSlash = strrchr(iniPath, PATH_SEPARATOR_CHAR);
   if (!lastSlash)
     return 1;

   *(++lastSlash) = '\0';
@@ -268,17 +309,17 @@ main(int argc, char **argv)
 #else
   greFound = (access(greDir, R_OK) == 0);
 #endif
   strncpy(lastSlash, "application.ini", sizeof(iniPath) - (lastSlash - iniPath));

 #endif

   nsINIParser parser;
-  rv = parser.Init(iniPath);
+  rv = (appDataFile && *appDataFile) ? parser.Init(appDataFile) : parser.Init(iniPath);
   if (NS_FAILED(rv)) {
     fprintf(stderr, "Could not read application.ini\n");
     return 1;
   }

   if (!greFound) {
     char minVersion[VERSION_MAXLEN];