Check argc before dereferencing argv[1], as we can launch xulrunner with no args if XUL_APP_FILE is set in the environment.

xulrunner/app/nsXULRunnerApp.cpp

@@ -312,61 +312,63 @@ int main(int argc, char* argv[])
     return 0;
   }
 
-  PRBool registerGlobal = IsArg(argv[1], "register-global");
-  PRBool registerUser   = IsArg(argv[1], "register-user");
-  if (registerGlobal || registerUser) {
-    if (argc != 2) {
-      Usage();
-      return 1;
-    }
+  if (argc > 1) {
+    PRBool registerGlobal = IsArg(argv[1], "register-global");
+    PRBool registerUser   = IsArg(argv[1], "register-user");
+    if (registerGlobal || registerUser) {
+      if (argc != 2) {
+	Usage();
+	return 1;
+      }
 
-    nsCOMPtr<nsIFile> regDir;
-    nsresult rv = GetXULRunnerDir(argv[0], getter_AddRefs(regDir));
-    if (NS_FAILED(rv))
+      nsCOMPtr<nsIFile> regDir;
+      nsresult rv = GetXULRunnerDir(argv[0], getter_AddRefs(regDir));
+      if (NS_FAILED(rv))
         return 2;
 
-    return RegisterXULRunner(registerGlobal, regDir) ? 0 : 2;
-  }
-
-  registerGlobal = IsArg(argv[1], "unregister-global");
-  registerUser   = IsArg(argv[1], "unregister-user");
-  if (IsArg(argv[1], "unregister-global")) {
-    if (argc != 2) {
-      Usage();
-      return 1;
+      return RegisterXULRunner(registerGlobal, regDir) ? 0 : 2;
     }
 
-    nsCOMPtr<nsIFile> regDir;
-    nsresult rv = GetXULRunnerDir(argv[0], getter_AddRefs(regDir));
-    if (NS_FAILED(rv))
+    registerGlobal = IsArg(argv[1], "unregister-global");
+    registerUser   = IsArg(argv[1], "unregister-user");
+    if (IsArg(argv[1], "unregister-global")) {
+      if (argc != 2) {
+	Usage();
+	return 1;
+      }
+
+      nsCOMPtr<nsIFile> regDir;
+      nsresult rv = GetXULRunnerDir(argv[0], getter_AddRefs(regDir));
+      if (NS_FAILED(rv))
         return 2;
-    UnregisterXULRunner(registerGlobal, regDir);
-    return 0;
-  }
-
-  if (IsArg(argv[1], "find-gre")) {
-    if (argc != 3) {
-      Usage();
-      return 1;
+      UnregisterXULRunner(registerGlobal, regDir);
+      return 0;
     }
 
-    char version[MAXPATHLEN];
-    nsresult rv = GRE_GetGREPathForVersion(argv[2], version, MAXPATHLEN);
-    if (NS_FAILED(rv))
-      return 1;
+    if (IsArg(argv[1], "find-gre")) {
+      if (argc != 3) {
+	Usage();
+	return 1;
+      }
 
-    printf("%s\n", version);
-    return 0;
-  }
+      char version[MAXPATHLEN];
+      nsresult rv = GRE_GetGREPathForVersion(argv[2], version, MAXPATHLEN);
+      if (NS_FAILED(rv))
+	return 1;
 
-  if (IsArg(argv[1], "gre-version")) {
-    if (argc != 2) {
-      Usage();
-      return 1;
+      printf("%s\n", version);
+      return 0;
     }
 
-    printf("%s\n", GRE_BUILD_ID);
-    return 0;
+    if (IsArg(argv[1], "gre-version")) {
+      if (argc != 2) {
+	Usage();
+	return 1;
+      }
+
+      printf("%s\n", GRE_BUILD_ID);
+      return 0;
+    }
   }
 
   geckoVersion = ParseVersion(GRE_BUILD_ID);