From: Iain Patterson <me@iain.cx>
Date: Mon, 23 Dec 2013 18:25:28 +0000 (+0000)
Subject: Allow editing services.
X-Git-Tag: v2.22~114
X-Git-Url: http://git.iain.cx/?p=nssm.git;a=commitdiff_plain;h=2c60e5334f6df07bf42e7a91cf59638453eca473

Allow editing services.

"nssm edit <service>" brings up a GUI to edit an existing service.
Services not managed by NSSM can also be edited but only system
properties such as the display name will appear in the GUI.
---

diff --git a/ChangeLog.txt b/ChangeLog.txt
index 911aa4d..004f597 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -1,5 +1,7 @@
 Changes since 2.21
 ------------------
+  * Existing services can now be edited using the GUI.
+
   * NSSM can now optionally rotate existing files when
     redirecting I/O.
 
diff --git a/README.txt b/README.txt
index d650970..0a0c47c 100644
--- a/README.txt
+++ b/README.txt
@@ -58,6 +58,8 @@ Since version 2.22, NSSM can rotate existing output files when redirecting I/O.
 Since version 2.22, NSSM can set service display name, description, startup
 type and log on details.
 
+Since version 2.22, NSSM can edit existing services with the GUI.
+
 
 Usage
 -----
@@ -281,6 +283,21 @@ omit the VALUE but the = symbol is mandatory.
 srvany only supports AppEnvironment.
 
 
+Managing services using the GUI
+-------------------------------
+NSSM can edit the settings of existing services with the same GUI that is
+used to install them.  Run
+
+    nssm edit <servicename>
+
+to bring up the GUI.
+
+NSSM offers limited editing capabilities for services other than those which
+run NSSM itself.  When NSSM is asked to edit a service which does not have
+the App* registry settings described above, the GUI will allow editing only
+system settings such as the service display name and description.
+
+
 Removing services using the GUI
 -------------------------------
 NSSM can also remove services.  Run
diff --git a/gui.cpp b/gui.cpp
index 240f62c..6fc5162 100644
--- a/gui.cpp
+++ b/gui.cpp
@@ -12,6 +12,9 @@ int nssm_gui(int resource, nssm_service_t *service) {
     return 1;
   }
 
+  /* Remember what the window is for. */
+  SetWindowLongPtr(dlg, GWLP_USERDATA, (LONG_PTR) resource);
+
   /* Display the window */
   centre_window(dlg);
   ShowWindow(dlg, SW_SHOW);
@@ -29,6 +32,126 @@ int nssm_gui(int resource, nssm_service_t *service) {
     }
   }
 
+  if (resource == IDD_EDIT) {
+    /* We'll need the service handle later. */
+    SetWindowLongPtr(dlg, DWLP_USER, (LONG_PTR) service);
+
+    /* Service name can't be edited. */
+    EnableWindow(GetDlgItem(dlg, IDC_NAME), 0);
+    SetFocus(GetDlgItem(dlg, IDOK));
+
+    /* Set existing details. */
+    HWND combo;
+
+    /* Application tab. */
+    if (service->native) SetDlgItemText(tablist[NSSM_TAB_APPLICATION], IDC_PATH, service->image);
+    else SetDlgItemText(tablist[NSSM_TAB_APPLICATION], IDC_PATH, service->exe);
+    SetDlgItemText(tablist[NSSM_TAB_APPLICATION], IDC_DIR, service->dir);
+    SetDlgItemText(tablist[NSSM_TAB_APPLICATION], IDC_FLAGS, service->flags);
+
+    /* Details tab. */
+    SetDlgItemText(tablist[NSSM_TAB_DETAILS], IDC_DISPLAYNAME, service->displayname);
+    SetDlgItemText(tablist[NSSM_TAB_DETAILS], IDC_DESCRIPTION, service->description);
+    combo = GetDlgItem(tablist[NSSM_TAB_DETAILS], IDC_STARTUP);
+    SendMessage(combo, CB_SETCURSEL, service->startup, 0);
+
+    /* Log on tab. */
+    if (service->username) {
+      CheckRadioButton(tablist[NSSM_TAB_LOGON], IDC_LOCALSYSTEM, IDC_ACCOUNT, IDC_ACCOUNT);
+      SetDlgItemText(tablist[NSSM_TAB_LOGON], IDC_USERNAME, service->username);
+      EnableWindow(GetDlgItem(tablist[NSSM_TAB_LOGON], IDC_INTERACT), 0);
+      EnableWindow(GetDlgItem(tablist[NSSM_TAB_LOGON], IDC_USERNAME), 1);
+      EnableWindow(GetDlgItem(tablist[NSSM_TAB_LOGON], IDC_PASSWORD1), 1);
+      EnableWindow(GetDlgItem(tablist[NSSM_TAB_LOGON], IDC_PASSWORD2), 1);
+    }
+    else {
+      CheckRadioButton(tablist[NSSM_TAB_LOGON], IDC_LOCALSYSTEM, IDC_ACCOUNT, IDC_LOCALSYSTEM);
+      if (service->type & SERVICE_INTERACTIVE_PROCESS) SendDlgItemMessage(tablist[NSSM_TAB_LOGON], IDC_INTERACT, BM_SETCHECK, BST_CHECKED, 0);
+    }
+
+    /* Shutdown tab. */
+    if (! (service->stop_method & NSSM_STOP_METHOD_CONSOLE)) {
+      SendDlgItemMessage(tablist[NSSM_TAB_SHUTDOWN], IDC_METHOD_CONSOLE, BM_SETCHECK, BST_UNCHECKED, 0);
+      EnableWindow(GetDlgItem(tablist[NSSM_TAB_SHUTDOWN], IDC_KILL_CONSOLE), 0);
+    }
+    SetDlgItemInt(tablist[NSSM_TAB_SHUTDOWN], IDC_KILL_CONSOLE, service->kill_console_delay, 0);
+    if (! (service->stop_method & NSSM_STOP_METHOD_WINDOW)) {
+      SendDlgItemMessage(tablist[NSSM_TAB_SHUTDOWN], IDC_METHOD_WINDOW, BM_SETCHECK, BST_UNCHECKED, 0);
+      EnableWindow(GetDlgItem(tablist[NSSM_TAB_SHUTDOWN], IDC_KILL_WINDOW), 0);
+    }
+    SetDlgItemInt(tablist[NSSM_TAB_SHUTDOWN], IDC_KILL_WINDOW, service->kill_window_delay, 0);
+    if (! (service->stop_method & NSSM_STOP_METHOD_THREADS)) {
+      SendDlgItemMessage(tablist[NSSM_TAB_SHUTDOWN], IDC_METHOD_THREADS, BM_SETCHECK, BST_UNCHECKED, 0);
+      EnableWindow(GetDlgItem(tablist[NSSM_TAB_SHUTDOWN], IDC_KILL_THREADS), 0);
+    }
+    SetDlgItemInt(tablist[NSSM_TAB_SHUTDOWN], IDC_KILL_THREADS, service->kill_threads_delay, 0);
+    if (! (service->stop_method & NSSM_STOP_METHOD_TERMINATE)) {
+      SendDlgItemMessage(tablist[NSSM_TAB_SHUTDOWN], IDC_METHOD_TERMINATE, BM_SETCHECK, BST_UNCHECKED, 0);
+    }
+
+    /* Restart tab. */
+    SetDlgItemInt(tablist[NSSM_TAB_EXIT], IDC_THROTTLE, service->throttle_delay, 0);
+    combo = GetDlgItem(tablist[NSSM_TAB_EXIT], IDC_APPEXIT);
+    SendMessage(combo, CB_SETCURSEL, service->default_exit_action, 0);
+
+    /* I/O tab. */
+    SetDlgItemText(tablist[NSSM_TAB_IO], IDC_STDIN, service->stdin_path);
+    SetDlgItemText(tablist[NSSM_TAB_IO], IDC_STDOUT, service->stdout_path);
+    SetDlgItemText(tablist[NSSM_TAB_IO], IDC_STDERR, service->stderr_path);
+
+    /* Rotation tab. */
+    if (service->stdout_disposition == CREATE_ALWAYS) SendDlgItemMessage(tablist[NSSM_TAB_ROTATION], IDC_TRUNCATE, BM_SETCHECK, BST_CHECKED, 0);
+    if (service->rotate_files) {
+      SendDlgItemMessage(tablist[NSSM_TAB_ROTATION], IDC_ROTATE, BM_SETCHECK, BST_CHECKED, 0);
+      EnableWindow(GetDlgItem(tablist[NSSM_TAB_ROTATION], IDC_ROTATE_SECONDS), 1);
+      EnableWindow(GetDlgItem(tablist[NSSM_TAB_ROTATION], IDC_ROTATE_BYTES_LOW), 1);
+    }
+    SetDlgItemInt(tablist[NSSM_TAB_ROTATION], IDC_ROTATE_SECONDS, service->rotate_seconds, 0);
+    if (! service->rotate_bytes_high) SetDlgItemInt(tablist[NSSM_TAB_ROTATION], IDC_ROTATE_BYTES_LOW, service->rotate_bytes_low, 0);
+
+    /* Check if advanced settings are in use. */
+    if (service->stdout_disposition ^ service->stderr_disposition || service->stdout_disposition & ~CREATE_ALWAYS || service->stderr_disposition & ~CREATE_ALWAYS) popup_message(MB_OK | MB_ICONWARNING, NSSM_GUI_WARN_STDIO);
+    if (service->rotate_bytes_high) popup_message(MB_OK | MB_ICONWARNING, NSSM_GUI_WARN_ROTATE_BYTES);
+
+    /* Environment tab. */
+    TCHAR *env;
+    unsigned long envlen;
+    if (service->env_extralen) {
+      SendDlgItemMessage(tablist[NSSM_TAB_ENVIRONMENT], IDC_ENVIRONMENT_REPLACE, BM_SETCHECK, BST_CHECKED, 0);
+      env = service->env_extra;
+      envlen = service->env_extralen;
+    }
+    else {
+      env = service->env;
+      envlen = service->envlen;
+    }
+
+    if (envlen) {
+      /* Replace NULL with CRLF. Leave NULL NULL as the end marker. */
+      unsigned long i, j;
+      unsigned long newlen = envlen;
+      for (i = 0; i < envlen; i++) if (! env[i] && env[i + 1]) newlen++;
+
+      TCHAR *formatted = (TCHAR *) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, newlen * sizeof(TCHAR));
+      if (formatted) {
+        for (i = 0, j = 0; i < envlen; i++) {
+          formatted[j] = env[i];
+          if (! env[i]) {
+            if (env[i + 1]) {
+              formatted[j] = _T('\r');
+              formatted[++j] = _T('\n');
+            }
+          }
+          j++;
+        }
+        SetDlgItemText(tablist[NSSM_TAB_ENVIRONMENT], IDC_ENVIRONMENT, formatted);
+        HeapFree(GetProcessHeap(), 0, formatted);
+      }
+      else popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_EVENT_OUT_OF_MEMORY, _T("environment"), _T("nssm_dlg()"));
+    }
+    if (service->envlen && service->env_extralen) popup_message(MB_OK | MB_ICONWARNING, NSSM_GUI_WARN_ENVIRONMENT);
+  }
+
   /* Go! */
   MSG message;
   while (GetMessage(&message, 0, 0, 0)) {
@@ -99,22 +222,26 @@ static inline void check_io(TCHAR *name, TCHAR *buffer, unsigned long len, unsig
   ZeroMemory(buffer, len * sizeof(TCHAR));
 }
 
-/* Install the service. */
-int install(HWND window) {
-  if (! window) return 1;
+/* Set service parameters. */
+int configure(HWND window, nssm_service_t *service, nssm_service_t *orig_service) {
+  if (! service) return 1;
 
-  nssm_service_t *service = alloc_nssm_service();
-  if (service) {
-    set_nssm_service_defaults(service);
+  set_nssm_service_defaults(service);
 
-    /* Get service name. */
-    if (! GetDlgItemText(window, IDC_NAME, service->name, _countof(service->name))) {
-      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_MISSING_SERVICE_NAME);
-      cleanup_nssm_service(service);
-      return 2;
-    }
+  if (orig_service) {
+    service->native = orig_service->native;
+    service->handle = orig_service->handle;
+  }
 
-    /* Get executable name */
+  /* Get service name. */
+  if (! GetDlgItemText(window, IDC_NAME, service->name, _countof(service->name))) {
+    popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_MISSING_SERVICE_NAME);
+    cleanup_nssm_service(service);
+    return 2;
+  }
+
+  /* Get executable name */
+  if (! service->native) {
     if (! GetDlgItemText(tablist[NSSM_TAB_APPLICATION], IDC_PATH, service->exe, _countof(service->exe))) {
       popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_MISSING_PATH);
       return 3;
@@ -133,54 +260,74 @@ int install(HWND window) {
         return 4;
       }
     }
+  }
 
-    /* Get details. */
-    if (SendMessage(GetDlgItem(tablist[NSSM_TAB_DETAILS], IDC_DISPLAYNAME), WM_GETTEXTLENGTH, 0, 0)) {
-      if (! GetDlgItemText(tablist[NSSM_TAB_DETAILS], IDC_DISPLAYNAME, service->displayname, _countof(service->displayname))) {
-        popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_INVALID_DISPLAYNAME);
-        return 5;
-      }
+  /* Get details. */
+  if (SendMessage(GetDlgItem(tablist[NSSM_TAB_DETAILS], IDC_DISPLAYNAME), WM_GETTEXTLENGTH, 0, 0)) {
+    if (! GetDlgItemText(tablist[NSSM_TAB_DETAILS], IDC_DISPLAYNAME, service->displayname, _countof(service->displayname))) {
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_INVALID_DISPLAYNAME);
+      return 5;
     }
+  }
 
-    if (SendMessage(GetDlgItem(tablist[NSSM_TAB_DETAILS], IDC_DESCRIPTION), WM_GETTEXTLENGTH, 0, 0)) {
-      if (! GetDlgItemText(tablist[NSSM_TAB_DETAILS], IDC_DESCRIPTION, service->description, _countof(service->description))) {
-        popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_INVALID_DESCRIPTION);
-        return 5;
-      }
+  if (SendMessage(GetDlgItem(tablist[NSSM_TAB_DETAILS], IDC_DESCRIPTION), WM_GETTEXTLENGTH, 0, 0)) {
+    if (! GetDlgItemText(tablist[NSSM_TAB_DETAILS], IDC_DESCRIPTION, service->description, _countof(service->description))) {
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_INVALID_DESCRIPTION);
+      return 5;
     }
+  }
 
-    HWND combo = GetDlgItem(tablist[NSSM_TAB_DETAILS], IDC_STARTUP);
-    service->startup = (unsigned long) SendMessage(combo, CB_GETCURSEL, 0, 0);
-    if (service->startup == CB_ERR) service->startup = 0;
+  HWND combo = GetDlgItem(tablist[NSSM_TAB_DETAILS], IDC_STARTUP);
+  service->startup = (unsigned long) SendMessage(combo, CB_GETCURSEL, 0, 0);
+  if (service->startup == CB_ERR) service->startup = 0;
 
-    /* Get logon stuff. */
-    if (SendDlgItemMessage(tablist[NSSM_TAB_LOGON], IDC_LOCALSYSTEM, BM_GETCHECK, 0, 0) & BST_CHECKED) {
-      if (SendDlgItemMessage(tablist[NSSM_TAB_LOGON], IDC_INTERACT, BM_GETCHECK, 0, 0) & BST_CHECKED) {
-        service->type |= SERVICE_INTERACTIVE_PROCESS;
-      }
+  /* Get logon stuff. */
+  if (SendDlgItemMessage(tablist[NSSM_TAB_LOGON], IDC_LOCALSYSTEM, BM_GETCHECK, 0, 0) & BST_CHECKED) {
+    if (SendDlgItemMessage(tablist[NSSM_TAB_LOGON], IDC_INTERACT, BM_GETCHECK, 0, 0) & BST_CHECKED) {
+      service->type |= SERVICE_INTERACTIVE_PROCESS;
     }
-    else {
-      /* Username. */
-      service->usernamelen = SendMessage(GetDlgItem(tablist[NSSM_TAB_LOGON], IDC_USERNAME), WM_GETTEXTLENGTH, 0, 0);
-      if (! service->usernamelen) {
-        popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_MISSING_USERNAME);
-        return 6;
-      }
-      service->usernamelen++;
+    if (service->username) HeapFree(GetProcessHeap(), 0, service->username);
+    service->username = 0;
+    service->usernamelen = 0;
+    if (service->password) {
+      SecureZeroMemory(service->password, service->passwordlen);
+      HeapFree(GetProcessHeap(), 0, service->password);
+    }
+    service->password = 0;
+    service->passwordlen = 0;
+  }
+  else {
+    /* Username. */
+    service->usernamelen = SendMessage(GetDlgItem(tablist[NSSM_TAB_LOGON], IDC_USERNAME), WM_GETTEXTLENGTH, 0, 0);
+    if (! service->usernamelen) {
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_MISSING_USERNAME);
+      return 6;
+    }
+    service->usernamelen++;
 
-      service->username = (TCHAR *) HeapAlloc(GetProcessHeap(), 0, service->usernamelen * sizeof(TCHAR));
-      if (! service->username) {
-        popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_EVENT_OUT_OF_MEMORY, _T("account name"), _T("install()"));
-        return 6;
-      }
-      if (! GetDlgItemText(tablist[NSSM_TAB_LOGON], IDC_USERNAME, service->username, (int) service->usernamelen)) {
-        HeapFree(GetProcessHeap(), 0, service->username);
-        service->username = 0;
-        service->usernamelen = 0;
-        popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_INVALID_USERNAME);
-        return 6;
-      }
+    service->username = (TCHAR *) HeapAlloc(GetProcessHeap(), 0, service->usernamelen * sizeof(TCHAR));
+    if (! service->username) {
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_EVENT_OUT_OF_MEMORY, _T("account name"), _T("install()"));
+      return 6;
+    }
+    if (! GetDlgItemText(tablist[NSSM_TAB_LOGON], IDC_USERNAME, service->username, (int) service->usernamelen)) {
+      HeapFree(GetProcessHeap(), 0, service->username);
+      service->username = 0;
+      service->usernamelen = 0;
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_INVALID_USERNAME);
+      return 6;
+    }
 
+    /*
+      Special case LOCALSYSTEM.
+      Ignore the password if we're editing and the username hasn't changed.
+    */
+    if (str_equiv(service->username, NSSM_LOCALSYSTEM_ACCOUNT)) {
+      HeapFree(GetProcessHeap(), 0, service->username);
+      service->username = 0;
+      service->usernamelen = 0;
+    }
+    else if (! orig_service || ! orig_service->username || ! str_equiv(service->username, orig_service->username)) {
       /* Password. */
       service->passwordlen = SendMessage(GetDlgItem(tablist[NSSM_TAB_LOGON], IDC_PASSWORD1), WM_GETTEXTLENGTH, 0, 0);
       if (! service->passwordlen) {
@@ -258,100 +405,116 @@ int install(HWND window) {
         return 6;
       }
     }
+  }
 
-    /* Get stop method stuff. */
-    check_stop_method(service, NSSM_STOP_METHOD_CONSOLE, IDC_METHOD_CONSOLE);
-    check_stop_method(service, NSSM_STOP_METHOD_WINDOW, IDC_METHOD_WINDOW);
-    check_stop_method(service, NSSM_STOP_METHOD_THREADS, IDC_METHOD_THREADS);
-    check_stop_method(service, NSSM_STOP_METHOD_TERMINATE, IDC_METHOD_TERMINATE);
-    check_number(tablist[NSSM_TAB_SHUTDOWN], IDC_KILL_CONSOLE, &service->kill_console_delay);
-    check_number(tablist[NSSM_TAB_SHUTDOWN], IDC_KILL_WINDOW, &service->kill_window_delay);
-    check_number(tablist[NSSM_TAB_SHUTDOWN], IDC_KILL_THREADS, &service->kill_threads_delay);
-
-    /* Get exit action stuff. */
-    check_number(tablist[NSSM_TAB_EXIT], IDC_THROTTLE, &service->throttle_delay);
-    combo = GetDlgItem(tablist[NSSM_TAB_EXIT], IDC_APPEXIT);
-    service->default_exit_action = (unsigned long) SendMessage(combo, CB_GETCURSEL, 0, 0);
-    if (service->default_exit_action == CB_ERR) service->default_exit_action = 0;
+  /* Remaining tabs are only for services we manage. */
+  if (service->native) return 0;
+
+  /* Get stop method stuff. */
+  check_stop_method(service, NSSM_STOP_METHOD_CONSOLE, IDC_METHOD_CONSOLE);
+  check_stop_method(service, NSSM_STOP_METHOD_WINDOW, IDC_METHOD_WINDOW);
+  check_stop_method(service, NSSM_STOP_METHOD_THREADS, IDC_METHOD_THREADS);
+  check_stop_method(service, NSSM_STOP_METHOD_TERMINATE, IDC_METHOD_TERMINATE);
+  check_number(tablist[NSSM_TAB_SHUTDOWN], IDC_KILL_CONSOLE, &service->kill_console_delay);
+  check_number(tablist[NSSM_TAB_SHUTDOWN], IDC_KILL_WINDOW, &service->kill_window_delay);
+  check_number(tablist[NSSM_TAB_SHUTDOWN], IDC_KILL_THREADS, &service->kill_threads_delay);
+
+  /* Get exit action stuff. */
+  check_number(tablist[NSSM_TAB_EXIT], IDC_THROTTLE, &service->throttle_delay);
+  combo = GetDlgItem(tablist[NSSM_TAB_EXIT], IDC_APPEXIT);
+  service->default_exit_action = (unsigned long) SendMessage(combo, CB_GETCURSEL, 0, 0);
+  if (service->default_exit_action == CB_ERR) service->default_exit_action = 0;
+
+  /* Get I/O stuff. */
+  check_io(_T("stdin"), service->stdin_path, _countof(service->stdin_path), IDC_STDIN);
+  check_io(_T("stdout"), service->stdout_path, _countof(service->stdout_path), IDC_STDOUT);
+  check_io(_T("stderr"), service->stderr_path, _countof(service->stderr_path), IDC_STDERR);
+
+  /* Override stdout and/or stderr. */
+  if (SendDlgItemMessage(tablist[NSSM_TAB_ROTATION], IDC_TRUNCATE, BM_GETCHECK, 0, 0) & BST_CHECKED) {
+    if (service->stdout_path[0]) service->stdout_disposition = CREATE_ALWAYS;
+    if (service->stderr_path[0]) service->stderr_disposition = CREATE_ALWAYS;
+  }
 
-    /* Get I/O stuff. */
-    check_io(_T("stdin"), service->stdin_path, _countof(service->stdin_path), IDC_STDIN);
-    check_io(_T("stdout"), service->stdout_path, _countof(service->stdout_path), IDC_STDOUT);
-    check_io(_T("stderr"), service->stderr_path, _countof(service->stderr_path), IDC_STDERR);
+  /* Get rotation stuff. */
+  if (SendDlgItemMessage(tablist[NSSM_TAB_ROTATION], IDC_ROTATE, BM_GETCHECK, 0, 0) & BST_CHECKED) {
+    service->rotate_files = true;
+    check_number(tablist[NSSM_TAB_ROTATION], IDC_ROTATE_SECONDS, &service->rotate_seconds);
+    check_number(tablist[NSSM_TAB_ROTATION], IDC_ROTATE_BYTES_LOW, &service->rotate_bytes_low);
+  }
 
-    /* Override stdout and/or stderr. */
-    if (SendDlgItemMessage(tablist[NSSM_TAB_ROTATION], IDC_TRUNCATE, BM_GETCHECK, 0, 0) & BST_CHECKED) {
-      if (service->stdout_path[0]) service->stdout_disposition = CREATE_ALWAYS;
-      if (service->stderr_path[0]) service->stderr_disposition = CREATE_ALWAYS;
+  /* Get environment. */
+  unsigned long envlen = (unsigned long) SendMessage(GetDlgItem(tablist[NSSM_TAB_ENVIRONMENT], IDC_ENVIRONMENT), WM_GETTEXTLENGTH, 0, 0);
+  if (envlen) {
+    TCHAR *env = (TCHAR *) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, (envlen + 2) * sizeof(TCHAR));
+    if (! env) {
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_EVENT_OUT_OF_MEMORY, _T("environment"), _T("install()"));
+      cleanup_nssm_service(service);
+      return 5;
     }
 
-    /* Get rotation stuff. */
-    if (SendDlgItemMessage(tablist[NSSM_TAB_ROTATION], IDC_ROTATE, BM_GETCHECK, 0, 0) & BST_CHECKED) {
-      service->rotate_files = true;
-      check_number(tablist[NSSM_TAB_ROTATION], IDC_ROTATE_SECONDS, &service->rotate_seconds);
-      check_number(tablist[NSSM_TAB_ROTATION], IDC_ROTATE_BYTES_LOW, &service->rotate_bytes_low);
+    if (! GetDlgItemText(tablist[NSSM_TAB_ENVIRONMENT], IDC_ENVIRONMENT, env, envlen + 1)) {
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_INVALID_ENVIRONMENT);
+      HeapFree(GetProcessHeap(), 0, env);
+      cleanup_nssm_service(service);
+      return 5;
     }
 
-    /* Get environment. */
-    unsigned long envlen = (unsigned long) SendMessage(GetDlgItem(tablist[NSSM_TAB_ENVIRONMENT], IDC_ENVIRONMENT), WM_GETTEXTLENGTH, 0, 0);
-    if (envlen) {
-      TCHAR *env = (TCHAR *) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, (envlen + 2) * sizeof(TCHAR));
-      if (! env) {
-        popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_EVENT_OUT_OF_MEMORY, _T("environment"), _T("install()"));
-        cleanup_nssm_service(service);
-        return 5;
-      }
+    /* Strip CR and replace LF with NULL. */
+    unsigned long newlen = 0;
+    unsigned long i, j;
+    for (i = 0; i < envlen; i++) if (env[i] != _T('\r')) newlen++;
+    /* Must end with two NULLs. */
+    newlen += 2;
 
-      if (! GetDlgItemText(tablist[NSSM_TAB_ENVIRONMENT], IDC_ENVIRONMENT, env, envlen + 1)) {
-        popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_INVALID_ENVIRONMENT);
-        HeapFree(GetProcessHeap(), 0, env);
-        cleanup_nssm_service(service);
-        return 5;
-      }
+    TCHAR *newenv = (TCHAR *) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, newlen * sizeof(TCHAR));
+    if (! newenv) {
+      HeapFree(GetProcessHeap(), 0, env);
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_EVENT_OUT_OF_MEMORY, _T("environment"), _T("install()"));
+      cleanup_nssm_service(service);
+      return 5;
+    }
 
-      /* Strip CR and replace LF with NULL. */
-      unsigned long newlen = 0;
-      unsigned long i, j;
-      for (i = 0; i < envlen; i++) if (env[i] != _T('\r')) newlen++;
-      /* Must end with two NULLs. */
-      newlen += 2;
-
-      TCHAR *newenv = (TCHAR *) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, newlen * sizeof(TCHAR));
-      if (! newenv) {
-        HeapFree(GetProcessHeap(), 0, env);
-        popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_EVENT_OUT_OF_MEMORY, _T("environment"), _T("install()"));
-        cleanup_nssm_service(service);
-        return 5;
-      }
+    for (i = 0, j = 0; i < envlen; i++) {
+      if (env[i] == _T('\r')) continue;
+      if (env[i] == _T('\n')) newenv[j] = _T('\0');
+      else newenv[j] = env[i];
+      j++;
+    }
 
-      for (i = 0, j = 0; i < envlen; i++) {
-        if (env[i] == _T('\r')) continue;
-        if (env[i] == _T('\n')) newenv[j] = _T('\0');
-        else newenv[j] = env[i];
-        j++;
-      }
+    HeapFree(GetProcessHeap(), 0, env);
+    env = newenv;
+    envlen = newlen;
 
+    /* Test the environment is valid. */
+    if (test_environment(env)) {
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_INVALID_ENVIRONMENT);
       HeapFree(GetProcessHeap(), 0, env);
-      env = newenv;
-      envlen = newlen;
-
-      /* Test the environment is valid. */
-      if (test_environment(env)) {
-        popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_INVALID_ENVIRONMENT);
-        HeapFree(GetProcessHeap(), 0, env);
-        cleanup_nssm_service(service);
-        return 5;
-      }
+      cleanup_nssm_service(service);
+      return 5;
+    }
 
-      if (SendDlgItemMessage(tablist[NSSM_TAB_ENVIRONMENT], IDC_ENVIRONMENT_REPLACE, BM_GETCHECK, 0, 0) & BST_CHECKED) {
-        service->env = env;
-        service->envlen = envlen;
-      }
-      else {
-        service->env_extra = env;
-        service->env_extralen = envlen;
-      }
+    if (SendDlgItemMessage(tablist[NSSM_TAB_ENVIRONMENT], IDC_ENVIRONMENT_REPLACE, BM_GETCHECK, 0, 0) & BST_CHECKED) {
+      service->env = env;
+      service->envlen = envlen;
     }
+    else {
+      service->env_extra = env;
+      service->env_extralen = envlen;
+    }
+  }
+
+  return 0;
+}
+
+/* Install the service. */
+int install(HWND window) {
+  if (! window) return 1;
+
+  nssm_service_t *service = alloc_nssm_service();
+  if (service) {
+    int ret = configure(window, service, 0);
+    if (ret) return ret;
   }
 
   /* See if it works. */
@@ -440,6 +603,42 @@ int remove(HWND window) {
   return 0;
 }
 
+int edit(HWND window, nssm_service_t *orig_service) {
+  if (! window) return 1;
+
+  nssm_service_t *service = alloc_nssm_service();
+  if (service) {
+    int ret = configure(window, service, orig_service);
+    if (ret) return ret;
+  }
+
+  switch (edit_service(service, true)) {
+    case 1:
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_EVENT_OUT_OF_MEMORY, _T("service"), _T("edit()"));
+      cleanup_nssm_service(service);
+      return 1;
+
+    case 3:
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_MESSAGE_PATH_TOO_LONG, NSSM);
+      cleanup_nssm_service(service);
+      return 3;
+
+    case 4:
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_OUT_OF_MEMORY_FOR_IMAGEPATH);
+      cleanup_nssm_service(service);
+      return 4;
+
+    case 6:
+      popup_message(MB_OK | MB_ICONEXCLAMATION, NSSM_GUI_EDIT_PARAMETERS_FAILED);
+      cleanup_nssm_service(service);
+      return 6;
+  }
+
+  popup_message(MB_OK, NSSM_MESSAGE_SERVICE_EDITED, service->name);
+  cleanup_nssm_service(service);
+  return 0;
+}
+
 static TCHAR *browse_filter(int message) {
   switch (message) {
     case NSSM_GUI_BROWSE_FILTER_APPLICATIONS: return _T("*.exe;*.bat;*.cmd");
@@ -606,9 +805,13 @@ INT_PTR CALLBACK tab_dlg(HWND tab, UINT message, WPARAM w, LPARAM l) {
 
 /* Install/remove dialogue callback */
 INT_PTR CALLBACK nssm_dlg(HWND window, UINT message, WPARAM w, LPARAM l) {
+  nssm_service_t *service;
+
   switch (message) {
     /* Creating the dialogue */
     case WM_INITDIALOG:
+      service = (nssm_service_t *) l;
+
       SetFocus(GetDlgItem(window, IDC_NAME));
 
       HWND tabs;
@@ -621,11 +824,19 @@ INT_PTR CALLBACK nssm_dlg(HWND window, UINT message, WPARAM w, LPARAM l) {
       ZeroMemory(&tab, sizeof(tab));
       tab.mask = TCIF_TEXT;
 
+      selected_tab = 0;
+
       /* Application tab. */
-      tab.pszText = message_string(NSSM_GUI_TAB_APPLICATION);
+      if (service->native) tab.pszText = message_string(NSSM_GUI_TAB_NATIVE);
+      else tab.pszText = message_string(NSSM_GUI_TAB_APPLICATION);
       tab.cchTextMax = (int) _tcslen(tab.pszText);
       SendMessage(tabs, TCM_INSERTITEM, NSSM_TAB_APPLICATION, (LPARAM) &tab);
-      tablist[NSSM_TAB_APPLICATION] = CreateDialog(0, MAKEINTRESOURCE(IDD_APPLICATION), window, tab_dlg);
+      if (service->native) {
+        tablist[NSSM_TAB_APPLICATION] = CreateDialog(0, MAKEINTRESOURCE(IDD_NATIVE), window, tab_dlg);
+        EnableWindow(tablist[NSSM_TAB_APPLICATION], 0);
+        EnableWindow(GetDlgItem(tablist[NSSM_TAB_APPLICATION], IDC_PATH), 0);
+      }
+      else tablist[NSSM_TAB_APPLICATION] = CreateDialog(0, MAKEINTRESOURCE(IDD_APPLICATION), window, tab_dlg);
       ShowWindow(tablist[NSSM_TAB_APPLICATION], SW_SHOW);
 
       /* Details tab. */
@@ -654,6 +865,9 @@ INT_PTR CALLBACK nssm_dlg(HWND window, UINT message, WPARAM w, LPARAM l) {
       CheckRadioButton(tablist[NSSM_TAB_LOGON], IDC_LOCALSYSTEM, IDC_ACCOUNT, IDC_LOCALSYSTEM);
       set_logon_enabled(0);
 
+      /* Remaining tabs are only for services we manage. */
+      if (service->native) return 1;
+
       /* Shutdown tab. */
       tab.pszText = message_string(NSSM_GUI_TAB_SHUTDOWN);
       tab.cchTextMax = (int) _tcslen(tab.pszText);
@@ -712,8 +926,6 @@ INT_PTR CALLBACK nssm_dlg(HWND window, UINT message, WPARAM w, LPARAM l) {
       tablist[NSSM_TAB_ENVIRONMENT] = CreateDialog(0, MAKEINTRESOURCE(IDD_ENVIRONMENT), window, tab_dlg);
       ShowWindow(tablist[NSSM_TAB_ENVIRONMENT], SW_HIDE);
 
-      selected_tab = 0;
-
       return 1;
 
     /* Tab change. */
@@ -732,12 +944,8 @@ INT_PTR CALLBACK nssm_dlg(HWND window, UINT message, WPARAM w, LPARAM l) {
           selection = (int) SendMessage(tabs, TCM_GETCURSEL, 0, 0);
           if (selection != selected_tab) {
             ShowWindow(tablist[selected_tab], SW_HIDE);
-            /*
-              XXX: Sets focus to the service name which isn't ideal but is
-                   better than leaving it in another tab.
-            */
             ShowWindow(tablist[selection], SW_SHOWDEFAULT);
-            SetFocus(tablist[selection]);
+            SetFocus(GetDlgItem(window, IDOK));
             selected_tab = selection;
           }
           return 1;
@@ -750,7 +958,10 @@ INT_PTR CALLBACK nssm_dlg(HWND window, UINT message, WPARAM w, LPARAM l) {
       switch (LOWORD(w)) {
         /* OK button */
         case IDOK:
-          if (! install(window)) PostQuitMessage(0);
+          if ((int) GetWindowLongPtr(window, GWLP_USERDATA) == IDD_EDIT) {
+            if (! edit(window, (nssm_service_t *) GetWindowLongPtr(window, DWLP_USER))) PostQuitMessage(0);
+          }
+          else if (! install(window)) PostQuitMessage(0);
           break;
 
         /* Cancel button */
diff --git a/gui.h b/gui.h
index 5cc9cea..a0ca9c6 100644
--- a/gui.h
+++ b/gui.h
@@ -8,8 +8,10 @@
 
 int nssm_gui(int, nssm_service_t *);
 void centre_window(HWND);
+int configure(HWND, nssm_service_t *, nssm_service_t *);
 int install(HWND);
 int remove(HWND);
+int edit(HWND, nssm_service_t *);
 void browse(HWND);
 INT_PTR CALLBACK nssm_dlg(HWND, UINT, WPARAM, LPARAM);
 
diff --git a/messages.mc b/messages.mc
index 4304d98..1a36fe2 100644
--- a/messages.mc
+++ b/messages.mc
@@ -21,6 +21,10 @@ To install a service without confirmation:
 
         nssm install <servicename> <app> [<args>]
 
+To show service editing GUI:
+
+        nssm edit <servicename>
+
 To show service removal GUI:
 
         nssm remove [<servicename>]
@@ -85,6 +89,19 @@ Language = Italian
 L'installazione di un servizio richiede privilegi di amministratore.
 .
 
+MessageId = +1
+SymbolicName = NSSM_MESSAGE_NOT_ADMINISTRATOR_CANNOT_EDIT
+Severity = Informational
+Language = English
+Administrator access is needed to edit a service.
+.
+Language = French
+Les droits d'administrateur sont requis pour éditer un service.
+.
+Language = Italian
+L'edizione di un servizio richiede privilegi di amministratore.
+.
+
 MessageId = +1
 SymbolicName = NSSM_MESSAGE_NOT_ADMINISTRATOR_CANNOT_REMOVE
 Severity = Informational
@@ -124,6 +141,67 @@ Language = Italian
 Errore apertura Service Manager!
 .
 
+MessageId = +1
+SymbolicName = NSSM_MESSAGE_QUERYSERVICECONFIG_FAILED
+Severity = Informational
+Language = English
+Error querying service %s!
+QueryServiceConfig(): %s%0
+.
+Language = French
+Error querying service %s!
+QueryServiceConfig(): %s%0
+.
+Language = Italian
+Error querying service %s!
+QueryServiceConfig(): %s%0
+.
+
+MessageId = +1
+SymbolicName = NSSM_MESSAGE_QUERYSERVICECONFIG2_FAILED
+Severity = Informational
+Language = English
+Error querying service %s!
+QueryServiceConfig2(%s): %s%0
+.
+Language = French
+Error querying service %s!
+QueryServiceConfig2(%s): %s%0
+.
+Language = Italian
+Error querying service %s!
+QueryServiceConfig2(%s): %s%0
+.
+
+MessageId = +1
+SymbolicName = NSSM_MESSAGE_INVALID_SERVICE
+Severity = Informational
+Language = English
+Service "%s" is not a valid %s service!
+Executable is %s%0
+.
+Language = French
+Service "%s" is not a valid %s service!
+Executable is %s%0
+.
+Language = Italian
+Service "%s" is not a valid %s service!
+Executable is %s%0
+.
+
+MessageId = +1
+SymbolicName = NSSM_MESSAGE_CANNOT_EDIT
+Severity = Informational
+Language = English
+Service "%s" is not a %s service!
+.
+Language = French
+Service "%s" is not a %s service!
+.
+Language = Italian
+Service "%s" is not a %s service!
+.
+
 MessageId = +1
 SymbolicName = NSSM_MESSAGE_PATH_TOO_LONG
 Severity = Informational
@@ -176,6 +254,22 @@ Language = Italian
 Errore creazione servizio!
 .
 
+MessageId = +1
+SymbolicName = NSSM_MESSAGE_CHANGESERVICECONFIG_FAILED
+Severity = Informational
+Language = English
+Error editing service!
+ChangeServiceConfig(): %s%0
+.
+Language = French
+Erreur à l'édition du service!
+ChangeServiceConfig(): %s%0
+.
+Language = Italian
+Errore edizione servizio!
+ChangeServiceConfig(): %s%0
+.
+
 MessageId = +1
 SymbolicName = NSSM_MESSAGE_CREATE_PARAMETERS_FAILED
 Severity = Informational
@@ -241,6 +335,19 @@ Language = Italian
 Servizio "%s" rimosso correttamente!
 .
 
+MessageId = +1
+SymbolicName = NSSM_MESSAGE_SERVICE_EDITED
+Severity = Informational
+Language = English
+Service "%s" edited successfully!
+.
+Language = French
+Le service "%s" a été édité avec succès!
+.
+Language = Italian
+Servizio "%s" edizione correttamente!
+.
+
 MessageId = +1
 SymbolicName = NSSM_GUI_CREATEDIALOG_FAILED
 Severity = Informational
@@ -436,6 +543,19 @@ Impossibile impostare i parametri di avvio per il servizio!
 Eliminazione servizio in corso...
 .
 
+MessageId = +1
+SymbolicName = NSSM_GUI_EDIT_PARAMETERS_FAILED
+Severity = Informational
+Language = English
+Couldn't set startup parameters for the service!
+.
+Language = French
+Impossible de régler les paramètres de démarrage pour le service!
+.
+Language = Italian
+Impossibile impostare i parametri di avvio per il servizio!
+.
+
 MessageId = +1
 SymbolicName = NSSM_GUI_ASK_REMOVE_SERVICE
 Severity = Informational
@@ -549,6 +669,19 @@ Language = Italian
 Applicazione%0
 .
 
+MessageId = +1
+SymbolicName = NSSM_GUI_TAB_NATIVE
+Severity = Informational
+Language = English
+Service%0
+.
+Language = French
+Service%0
+.
+Language = Italian
+Servizio%0
+.
+
 MessageId = +1
 SymbolicName = NSSM_GUI_TAB_DETAILS
 Severity = Informational
@@ -744,6 +877,66 @@ Language = Italian
 Fake crash (pre-Vista)%0
 .
 
+MessageId = +1
+SymbolicName = NSSM_GUI_WARN_STDIO
+Severity = Informational
+Language = English
+The service is configured with I/O redirection settings which cannot be
+represented by this GUI's simplified set of options.  Check the registry
+after editing the service to confirm its I/O redirection settings.
+.
+Language = French
+The service is configured with I/O redirection settings which cannot be
+represented by this GUI's simplified set of options.  Check the registry
+after editing the service to confirm its I/O redirection settings.
+.
+Language = Italian
+The service is configured with I/O redirection settings which cannot be
+represented by this GUI's simplified set of options.  Check the registry
+after editing the service to confirm its I/O redirection settings.
+.
+
+MessageId = +1
+SymbolicName = NSSM_GUI_WARN_ROTATE_BYTES
+Severity = Informational
+Language = English
+The service is configured with a 64-bit file size threshold for file
+rotation.  This GUI can only display 32-bit settings.  Check the registry
+after editing the service to confirm its file rotation settings.
+.
+Language = French
+The service is configured with a 64-bit file size threshold for file
+rotation.  This GUI can only display 32-bit settings.  Check the registry
+after editing the service to confirm its file rotation settings.
+.
+Language = Italian
+The service is configured with a 64-bit file size threshold for file
+rotation.  This GUI can only display 32-bit settings.  Check the registry
+after editing the service to confirm its file rotation settings.
+.
+
+MessageId = +1
+SymbolicName = NSSM_GUI_WARN_ENVIRONMENT
+Severity = Informational
+Language = English
+The service is configured with a srvany-compatible environment block
+for the application as well as an extra environment block.  This GUI
+can only display one such block.  Editing the service will result in
+one of the environment blocks being deleted.
+.
+Language = French
+The service is configured with a srvany-compatible environment block
+for the application as well as an extra environment block.  This GUI
+can only display one such block.  Editing the service will result in
+one of the environment blocks being deleted.
+.
+Language = Italian
+The service is configured with a srvany-compatible environment block
+for the application as well as an extra environment block.  This GUI
+can only display one such block.  Editing the service will result in
+one of the environment blocks being deleted.
+.
+
 MessageId = 1001
 SymbolicName = NSSM_EVENT_DISPATCHER_FAILED
 Severity = Error
diff --git a/nssm.cpp b/nssm.cpp
index 86a1827..7c95611 100644
--- a/nssm.cpp
+++ b/nssm.cpp
@@ -45,7 +45,7 @@ int _tmain(int argc, TCHAR **argv) {
 
   /* Elevate */
   if (argc > 1) {
-    /* Valid commands are install or remove */
+    /* Valid commands are install, edit or remove */
     if (str_equiv(argv[1], _T("install"))) {
       if (! is_admin) {
         print_message(stderr, NSSM_MESSAGE_NOT_ADMINISTRATOR_CANNOT_INSTALL);
@@ -53,6 +53,13 @@ int _tmain(int argc, TCHAR **argv) {
       }
       exit(pre_install_service(argc - 2, argv + 2));
     }
+    if (str_equiv(argv[1], _T("edit"))) {
+      if (! is_admin) {
+        print_message(stderr, NSSM_MESSAGE_NOT_ADMINISTRATOR_CANNOT_EDIT);
+        exit(100);
+      }
+      exit(pre_edit_service(argc - 2, argv + 2));
+    }
     if (str_equiv(argv[1], _T("remove"))) {
       if (! is_admin) {
         print_message(stderr, NSSM_MESSAGE_NOT_ADMINISTRATOR_CANNOT_REMOVE);
diff --git a/nssm.h b/nssm.h
index bdefdbe..46308d5 100644
--- a/nssm.h
+++ b/nssm.h
@@ -18,6 +18,7 @@
 
 int str_equiv(const TCHAR *, const TCHAR *);
 void strip_basename(TCHAR *);
+int usage(int);
 
 #define NSSM _T("nssm")
 #define NSSM_VERSION _T("2.21")
diff --git a/nssm.rc b/nssm.rc
index 5c21be3..3cf4d3f 100644
--- a/nssm.rc
+++ b/nssm.rc
@@ -86,6 +86,19 @@ BEGIN
     EDITTEXT        IDC_NAME,59,7,87,14,ES_AUTOHSCROLL
 END
 
+LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
+IDD_EDIT DIALOG 0, 0, 286, 126
+STYLE DS_MODALFRAME | DS_SETFONT | WS_CAPTION | WS_POPUP | WS_SYSMENU
+CAPTION "NSSM service editor"
+FONT 8, "MS Sans Serif"
+{
+    CONTROL         "", IDC_TAB1, WC_TABCONTROL, 0, 7, 7, 269, 93
+    LTEXT           "Service name:", IDC_STATIC, 7, 106, 52, 8, SS_LEFT
+    EDITTEXT        IDC_NAME, 64, 104, 98, 12, ES_AUTOHSCROLL
+    DEFPUSHBUTTON   "Edit service", IDOK, 172, 104, 50, 14
+    PUSHBUTTON      "Cancel", IDCANCEL, 227, 104, 50, 14
+}
+
 LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
 IDD_APPLICATION DIALOG 9, 20, 261, 75
 STYLE DS_SHELLFONT | WS_VISIBLE | WS_CHILD | DS_CONTROL
@@ -102,6 +115,16 @@ FONT 8, "MS Sans Serif"
     EDITTEXT        IDC_FLAGS, 70, 48, 184, 12, ES_AUTOHSCROLL, WS_EX_ACCEPTFILES
 }
 
+LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
+IDD_NATIVE DIALOG 9, 20, 261, 75
+STYLE DS_SHELLFONT | WS_VISIBLE | WS_CHILD | DS_CONTROL
+FONT 8, "MS Sans Serif"
+{
+    GROUPBOX        "Service", IDC_STATIC, 7, 7, 251, 68
+    LTEXT           "Image path:", IDC_STATIC, 13, 18, 53, 8, SS_LEFT
+    EDITTEXT        IDC_PATH, 70, 16, 184, 12, ES_AUTOHSCROLL, WS_EX_ACCEPTFILES
+}
+
 
 
 LANGUAGE LANG_NEUTRAL, SUBLANG_NEUTRAL
@@ -308,6 +331,19 @@ BEGIN
     EDITTEXT        IDC_NAME,43,7,90,14,ES_AUTOHSCROLL
 END
 
+LANGUAGE LANG_FRENCH, SUBLANG_FRENCH
+IDD_EDIT DIALOG 0, 0, 282, 126
+STYLE DS_MODALFRAME | DS_SETFONT | WS_CAPTION | WS_POPUP | WS_SYSMENU
+CAPTION "Edition d'un service NSSM"
+FONT 8, "MS Sans Serif"
+{
+    CONTROL         "", IDC_TAB1, WC_TABCONTROL, 0, 7, 7, 269, 93
+    LTEXT           "Nom du service:", IDC_STATIC, 7, 106, 52, 8, SS_LEFT
+    EDITTEXT        IDC_NAME, 64, 104, 98, 12, ES_AUTOHSCROLL
+    DEFPUSHBUTTON   "Editer le service", IDOK, 172, 106, 50, 14
+    PUSHBUTTON      "Anuller", IDCANCEL, 227, 106, 50, 14
+}
+
 LANGUAGE LANG_FRENCH, SUBLANG_FRENCH
 IDD_APPLICATION DIALOG 9, 20, 261, 75
 STYLE DS_SHELLFONT | WS_VISIBLE | WS_CHILD | DS_CONTROL
@@ -324,6 +360,16 @@ FONT 8, "MS Sans Serif"
     EDITTEXT        IDC_FLAGS, 80, 45, 174, 12, ES_AUTOHSCROLL, WS_EX_ACCEPTFILES
 }
 
+LANGUAGE LANG_FRENCH, SUBLANG_FRENCH
+IDD_NATIVE DIALOG 9, 20, 261, 75
+STYLE DS_SHELLFONT | WS_VISIBLE | WS_CHILD | DS_CONTROL
+FONT 8, "MS Sans Serif"
+{
+    GROUPBOX        "Service", IDC_STATIC, 7, 7, 251, 68
+    LTEXT           "Chemin:", IDC_STATIC, 13, 18, 53, 8, SS_LEFT
+    EDITTEXT        IDC_PATH, 70, 16, 184, 12, ES_AUTOHSCROLL, WS_EX_ACCEPTFILES
+}
+
 
 /////////////////////////////////////////////////////////////////////////////
 //
@@ -433,6 +479,19 @@ BEGIN
     EDITTEXT        IDC_NAME,59,7,87,14,ES_AUTOHSCROLL
 END
 
+LANGUAGE LANG_ITALIAN, SUBLANG_ITALIAN
+IDD_EDIT DIALOG 0, 0, 282, 126
+STYLE DS_MODALFRAME | DS_SETFONT | WS_CAPTION | WS_POPUP | WS_SYSMENU
+CAPTION "NSSM - Edizione Servizio"
+FONT 8, "MS Sans Serif"
+{
+    CONTROL         "", IDC_TAB1, WC_TABCONTROL, 0, 7, 7, 269, 93
+    LTEXT           "Nome servizio:", IDC_STATIC, 7, 106, 52, 8, SS_LEFT
+    EDITTEXT        IDC_NAME, 64, 104, 98, 12, ES_AUTOHSCROLL
+    DEFPUSHBUTTON   "Edita servizio", IDOK, 172, 106, 50, 14
+    PUSHBUTTON      "Anulla", IDCANCEL, 227, 106, 50, 14
+}
+
 LANGUAGE LANG_ITALIAN, SUBLANG_ITALIAN
 IDD_APPLICATION DIALOG 9, 20, 261, 75
 STYLE DS_SHELLFONT | WS_VISIBLE | WS_CHILD | DS_CONTROL
@@ -449,6 +508,16 @@ FONT 8, "MS Sans Serif"
     EDITTEXT        IDC_FLAGS, 70, 46, 184, 12, ES_AUTOHSCROLL, WS_EX_ACCEPTFILES
 }
 
+LANGUAGE LANG_ITALIAN, SUBLANG_ITALIAN
+IDD_NATIVE DIALOG 9, 20, 261, 75
+STYLE DS_SHELLFONT | WS_VISIBLE | WS_CHILD | DS_CONTROL
+FONT 8, "MS Sans Serif"
+{
+    GROUPBOX        "Servizio", IDC_STATIC, 7, 7, 251, 68
+    LTEXT           "Path:", IDC_STATIC, 13, 18, 53, 8, SS_LEFT
+    EDITTEXT        IDC_PATH, 70, 16, 184, 12, ES_AUTOHSCROLL, WS_EX_ACCEPTFILES
+}
+
 
 /////////////////////////////////////////////////////////////////////////////
 //
diff --git a/registry.cpp b/registry.cpp
index 74fe047..d226b83 100644
--- a/registry.cpp
+++ b/registry.cpp
@@ -28,7 +28,7 @@ int create_messages() {
   return 0;
 }
 
-int create_parameters(nssm_service_t *service) {
+int create_parameters(nssm_service_t *service, bool editing) {
   /* Get registry */
   TCHAR registry[KEY_LENGTH];
   if (_sntprintf_s(registry, _countof(registry), _TRUNCATE, NSSM_REGISTRY, service->name) < 0) {
@@ -63,33 +63,54 @@ int create_parameters(nssm_service_t *service) {
   /* Other non-default parameters. May fail. */
   unsigned long stop_method_skip = ~service->stop_method;
   if (stop_method_skip) set_number(key, NSSM_REG_STOP_METHOD_SKIP, stop_method_skip);
-  if (service->default_exit_action < NSSM_NUM_EXIT_ACTIONS) create_exit_action(service->name, exit_action_strings[service->default_exit_action]);
+  else if (editing) RegDeleteValue(key, NSSM_REG_STOP_METHOD_SKIP);
+  if (service->default_exit_action < NSSM_NUM_EXIT_ACTIONS) create_exit_action(service->name, exit_action_strings[service->default_exit_action], editing);
   if (service->throttle_delay != NSSM_RESET_THROTTLE_RESTART) set_number(key, NSSM_REG_THROTTLE, service->throttle_delay);
+  else if (editing) RegDeleteValue(key, NSSM_REG_THROTTLE);
   if (service->kill_console_delay != NSSM_KILL_CONSOLE_GRACE_PERIOD) set_number(key, NSSM_REG_KILL_CONSOLE_GRACE_PERIOD, service->kill_console_delay);
+  else if (editing) RegDeleteValue(key, NSSM_REG_KILL_CONSOLE_GRACE_PERIOD);
   if (service->kill_window_delay != NSSM_KILL_WINDOW_GRACE_PERIOD) set_number(key, NSSM_REG_KILL_WINDOW_GRACE_PERIOD, service->kill_window_delay);
+  else if (editing) RegDeleteValue(key, NSSM_REG_KILL_WINDOW_GRACE_PERIOD);
   if (service->kill_threads_delay != NSSM_KILL_THREADS_GRACE_PERIOD) set_number(key, NSSM_REG_KILL_THREADS_GRACE_PERIOD, service->kill_threads_delay);
-  if (service->stdin_path[0]) {
-    set_expand_string(key, NSSM_REG_STDIN, service->stdin_path);
+  else if (editing) RegDeleteValue(key, NSSM_REG_KILL_THREADS_GRACE_PERIOD);
+  if (service->stdin_path[0] || editing) {
+    if (service->stdin_path[0]) set_expand_string(key, NSSM_REG_STDIN, service->stdin_path);
+    else if (editing) RegDeleteValue(key, NSSM_REG_STDIN);
     if (service->stdin_sharing != NSSM_STDIN_SHARING) set_createfile_parameter(key, NSSM_REG_STDIN, NSSM_REG_STDIO_SHARING, service->stdin_sharing);
+    else if (editing) delete_createfile_parameter(key, NSSM_REG_STDIN, NSSM_REG_STDIO_SHARING);
     if (service->stdin_disposition != NSSM_STDIN_DISPOSITION) set_createfile_parameter(key, NSSM_REG_STDIN, NSSM_REG_STDIO_DISPOSITION, service->stdin_disposition);
+    else if (editing) delete_createfile_parameter(key, NSSM_REG_STDIN, NSSM_REG_STDIO_DISPOSITION);
     if (service->stdin_flags != NSSM_STDIN_FLAGS) set_createfile_parameter(key, NSSM_REG_STDIN, NSSM_REG_STDIO_FLAGS, service->stdin_flags);
+    else if (editing) delete_createfile_parameter(key, NSSM_REG_STDIN, NSSM_REG_STDIO_FLAGS);
   }
-  if (service->stdout_path[0]) {
-    set_expand_string(key, NSSM_REG_STDOUT, service->stdout_path);
+  if (service->stdout_path[0] || editing) {
+    if (service->stdout_path[0]) set_expand_string(key, NSSM_REG_STDOUT, service->stdout_path);
+    else if (editing) RegDeleteValue(key, NSSM_REG_STDOUT);
     if (service->stdout_sharing != NSSM_STDOUT_SHARING) set_createfile_parameter(key, NSSM_REG_STDOUT, NSSM_REG_STDIO_SHARING, service->stdout_sharing);
+    else if (editing) delete_createfile_parameter(key, NSSM_REG_STDOUT, NSSM_REG_STDIO_SHARING);
     if (service->stdout_disposition != NSSM_STDOUT_DISPOSITION) set_createfile_parameter(key, NSSM_REG_STDOUT, NSSM_REG_STDIO_DISPOSITION, service->stdout_disposition);
+    else if (editing) delete_createfile_parameter(key, NSSM_REG_STDOUT, NSSM_REG_STDIO_DISPOSITION);
     if (service->stdout_flags != NSSM_STDOUT_FLAGS) set_createfile_parameter(key, NSSM_REG_STDOUT, NSSM_REG_STDIO_FLAGS, service->stdout_flags);
+    else if (editing) delete_createfile_parameter(key, NSSM_REG_STDOUT, NSSM_REG_STDIO_FLAGS);
   }
-  if (service->stderr_path[0]) {
-    set_expand_string(key, NSSM_REG_STDERR, service->stderr_path);
+  if (service->stderr_path[0] || editing) {
+    if (service->stderr_path[0]) set_expand_string(key, NSSM_REG_STDERR, service->stderr_path);
+    else if (editing) RegDeleteValue(key, NSSM_REG_STDERR);
     if (service->stderr_sharing != NSSM_STDERR_SHARING) set_createfile_parameter(key, NSSM_REG_STDERR, NSSM_REG_STDIO_SHARING, service->stderr_sharing);
+    else if (editing) delete_createfile_parameter(key, NSSM_REG_STDERR, NSSM_REG_STDIO_SHARING);
     if (service->stderr_disposition != NSSM_STDERR_DISPOSITION) set_createfile_parameter(key, NSSM_REG_STDERR, NSSM_REG_STDIO_DISPOSITION, service->stderr_disposition);
+    else if (editing) delete_createfile_parameter(key, NSSM_REG_STDERR, NSSM_REG_STDIO_DISPOSITION);
     if (service->stderr_flags != NSSM_STDERR_FLAGS) set_createfile_parameter(key, NSSM_REG_STDERR, NSSM_REG_STDIO_FLAGS, service->stderr_flags);
+    else if (editing) delete_createfile_parameter(key, NSSM_REG_STDERR, NSSM_REG_STDIO_FLAGS);
   }
   if (service->rotate_files) set_number(key, NSSM_REG_ROTATE, 1);
+  else if (editing) RegDeleteValue(key, NSSM_REG_ROTATE);
   if (service->rotate_seconds) set_number(key, NSSM_REG_ROTATE_SECONDS, service->rotate_seconds);
+  else if (editing) RegDeleteValue(key, NSSM_REG_ROTATE_SECONDS);
   if (service->rotate_bytes_low) set_number(key, NSSM_REG_ROTATE_BYTES_LOW, service->rotate_bytes_low);
+  else if (editing) RegDeleteValue(key, NSSM_REG_ROTATE_BYTES_LOW);
   if (service->rotate_bytes_high) set_number(key, NSSM_REG_ROTATE_BYTES_HIGH, service->rotate_bytes_high);
+  else if (editing) RegDeleteValue(key, NSSM_REG_ROTATE_BYTES_HIGH);
 
   /* Environment */
   if (service->env) {
@@ -97,11 +118,13 @@ int create_parameters(nssm_service_t *service) {
       log_event(EVENTLOG_ERROR_TYPE, NSSM_EVENT_SETVALUE_FAILED, NSSM_REG_ENV, error_string(GetLastError()), 0);
     }
   }
+  else if (editing) RegDeleteValue(key, NSSM_REG_ENV);
   if (service->env_extra) {
     if (RegSetValueEx(key, NSSM_REG_ENV_EXTRA, 0, REG_MULTI_SZ, (const unsigned char *) service->env_extra, (unsigned long) service->env_extralen * sizeof(TCHAR)) != ERROR_SUCCESS) {
       log_event(EVENTLOG_ERROR_TYPE, NSSM_EVENT_SETVALUE_FAILED, NSSM_REG_ENV_EXTRA, error_string(GetLastError()), 0);
     }
   }
+  else if (editing) RegDeleteValue(key, NSSM_REG_ENV_EXTRA);
 
   /* Close registry. */
   RegCloseKey(key);
@@ -109,7 +132,7 @@ int create_parameters(nssm_service_t *service) {
   return 0;
 }
 
-int create_exit_action(TCHAR *service_name, const TCHAR *action_string) {
+int create_exit_action(TCHAR *service_name, const TCHAR *action_string, bool editing) {
   /* Get registry */
   TCHAR registry[KEY_LENGTH];
   if (_sntprintf_s(registry, _countof(registry), _TRUNCATE, NSSM_REGISTRY _T("\\%s"), service_name, NSSM_REG_EXIT) < 0) {
@@ -126,7 +149,7 @@ int create_exit_action(TCHAR *service_name, const TCHAR *action_string) {
   }
 
   /* Do nothing if the key already existed */
-  if (disposition == REG_OPENED_EXISTING_KEY) {
+  if (disposition == REG_OPENED_EXISTING_KEY && ! editing) {
     RegCloseKey(key);
     return 0;
   }
@@ -452,6 +475,19 @@ int get_parameters(nssm_service_t *service, STARTUPINFO *si) {
   override_milliseconds(service->name, key, NSSM_REG_KILL_WINDOW_GRACE_PERIOD, &service->kill_window_delay, NSSM_KILL_WINDOW_GRACE_PERIOD, NSSM_EVENT_BOGUS_KILL_WINDOW_GRACE_PERIOD);
   override_milliseconds(service->name, key, NSSM_REG_KILL_THREADS_GRACE_PERIOD, &service->kill_threads_delay, NSSM_KILL_THREADS_GRACE_PERIOD, NSSM_EVENT_BOGUS_KILL_THREADS_GRACE_PERIOD);
 
+  /* Try to get default exit action. */
+  bool default_action;
+  service->default_exit_action = NSSM_EXIT_RESTART;
+  TCHAR action_string[ACTION_LEN];
+  if (! get_exit_action(service->name, 0, action_string, &default_action)) {
+    for (int i = 0; exit_action_strings[i]; i++) {
+      if (! _tcsnicmp((const TCHAR *) action_string, exit_action_strings[i], ACTION_LEN)) {
+        service->default_exit_action = i;
+        break;
+      }
+    }
+  }
+
   /* Close registry */
   RegCloseKey(key);
 
diff --git a/registry.h b/registry.h
index 600c188..564e674 100644
--- a/registry.h
+++ b/registry.h
@@ -26,8 +26,8 @@
 #define NSSM_STDIO_LENGTH 29
 
 int create_messages();
-int create_parameters(nssm_service_t *);
-int create_exit_action(TCHAR *, const TCHAR *);
+int create_parameters(nssm_service_t *, bool);
+int create_exit_action(TCHAR *, const TCHAR *, bool);
 int set_environment(TCHAR *, HKEY, TCHAR *, TCHAR **, unsigned long *);
 int expand_parameter(HKEY, TCHAR *, TCHAR *, unsigned long, bool, bool);
 int expand_parameter(HKEY, TCHAR *, TCHAR *, unsigned long, bool);
diff --git a/resource.h b/resource.h
index 6964003..bebd411 100644
--- a/resource.h
+++ b/resource.h
@@ -6,14 +6,16 @@
 #define IDI_NSSM                        101
 #define IDD_INSTALL                     102
 #define IDD_REMOVE                      103
-#define IDD_APPLICATION                 104
-#define IDD_DETAILS                     105
-#define IDD_LOGON                       106
-#define IDD_IO                          107
-#define IDD_ROTATION                    108
-#define IDD_APPEXIT                     109
-#define IDD_SHUTDOWN                    110
-#define IDD_ENVIRONMENT                 111
+#define IDD_EDIT                        104
+#define IDD_APPLICATION                 105
+#define IDD_DETAILS                     106
+#define IDD_LOGON                       107
+#define IDD_IO                          108
+#define IDD_ROTATION                    109
+#define IDD_APPEXIT                     110
+#define IDD_SHUTDOWN                    111
+#define IDD_ENVIRONMENT                 112
+#define IDD_NATIVE                      113
 #define IDC_PATH                        1000
 #define IDC_TAB1                        1001
 #define IDC_CANCEL                      1002
@@ -58,7 +60,7 @@
 // 
 #ifdef APSTUDIO_INVOKED
 #ifndef APSTUDIO_READONLY_SYMBOLS
-#define _APS_NEXT_RESOURCE_VALUE        112
+#define _APS_NEXT_RESOURCE_VALUE        114
 #define _APS_NEXT_COMMAND_VALUE         40001
 #define _APS_NEXT_CONTROL_VALUE         1040
 #define _APS_NEXT_SYMED_VALUE           101
diff --git a/service.cpp b/service.cpp
index 09fbe1f..b246443 100644
--- a/service.cpp
+++ b/service.cpp
@@ -1,5 +1,7 @@
 #include "nssm.h"
 
+extern const TCHAR *exit_action_strings[];
+
 bool is_admin;
 bool use_critical_section;
 
@@ -120,6 +122,172 @@ int pre_install_service(int argc, TCHAR **argv) {
   return ret;
 }
 
+/* About to edit the service. */
+int pre_edit_service(int argc, TCHAR **argv) {
+  /* Require service name. */
+  if (argc < 1) return usage(1);
+
+  nssm_service_t *service = alloc_nssm_service();
+  _sntprintf_s(service->name, _countof(service->name), _TRUNCATE, _T("%s"), argv[0]);
+
+  /* Open service manager */
+  SC_HANDLE services = open_service_manager();
+  if (! services) {
+    print_message(stderr, NSSM_MESSAGE_OPEN_SERVICE_MANAGER_FAILED);
+    return 2;
+  }
+
+  /* Try to open the service */
+  service->handle = OpenService(services, service->name, SC_MANAGER_ALL_ACCESS);
+  if (! service->handle) {
+    CloseServiceHandle(services);
+    print_message(stderr, NSSM_MESSAGE_OPENSERVICE_FAILED);
+    return 3;
+  }
+
+  /* Get system details. */
+  unsigned long bufsize;
+  unsigned long error;
+  QUERY_SERVICE_CONFIG *qsc;
+
+  QueryServiceConfig(service->handle, 0, 0, &bufsize);
+  error = GetLastError();
+  if (error == ERROR_INSUFFICIENT_BUFFER) {
+    qsc = (QUERY_SERVICE_CONFIG *) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, bufsize);
+    if (! qsc) {
+      print_message(stderr, NSSM_EVENT_OUT_OF_MEMORY, _T("QUERY_SERVICE_CONFIG"), _T("pre_edit_service()"), 0);
+      return 4;
+    }
+  }
+  else {
+    CloseHandle(service->handle);
+    CloseServiceHandle(services);
+    print_message(stderr, NSSM_MESSAGE_QUERYSERVICECONFIG_FAILED, service->name, error_string(error), 0);
+    return 4;
+  }
+
+  if (! QueryServiceConfig(service->handle, qsc, bufsize, &bufsize)) {
+    HeapFree(GetProcessHeap(), 0, qsc);
+    CloseHandle(service->handle);
+    CloseServiceHandle(services);
+    print_message(stderr, NSSM_MESSAGE_QUERYSERVICECONFIG_FAILED, service->name, error_string(GetLastError()), 0);
+    return 4;
+  }
+
+  service->type = qsc->dwServiceType;
+  if (! (service->type & SERVICE_WIN32_OWN_PROCESS)) {
+    HeapFree(GetProcessHeap(), 0, qsc);
+    CloseHandle(service->handle);
+    CloseServiceHandle(services);
+    print_message(stderr, NSSM_MESSAGE_CANNOT_EDIT, service->name, _T("SERVICE_WIN32_OWN_PROCESS"), 0);
+    return 3;
+  }
+
+  switch (qsc->dwStartType) {
+    case SERVICE_DEMAND_START: service->startup = NSSM_STARTUP_MANUAL; break;
+    case SERVICE_DISABLED: service->startup = NSSM_STARTUP_DISABLED; break;
+    default: service->startup = NSSM_STARTUP_AUTOMATIC;
+  }
+  if (! str_equiv(qsc->lpServiceStartName, NSSM_LOCALSYSTEM_ACCOUNT)) {
+    size_t len = _tcslen(qsc->lpServiceStartName);
+    service->username = (TCHAR *) HeapAlloc(GetProcessHeap(), 0, (len + 1) * sizeof(TCHAR));
+    if (service->username) {
+      memmove(service->username, qsc->lpServiceStartName, (len + 1) * sizeof(TCHAR));
+      service->usernamelen = (unsigned long) len;
+    }
+    else {
+      HeapFree(GetProcessHeap(), 0, qsc);
+      CloseHandle(service->handle);
+      CloseServiceHandle(services);
+      print_message(stderr, NSSM_EVENT_OUT_OF_MEMORY, _T("username"), _T("pre_edit_service()"));
+      return 4;
+    }
+  }
+  _sntprintf_s(service->displayname, _countof(service->displayname), _TRUNCATE, _T("%s"), qsc->lpDisplayName);
+
+  /* Remember the executable in case it isn't NSSM. */
+  _sntprintf_s(service->image, _countof(service->image), _TRUNCATE, _T("%s"), qsc->lpBinaryPathName);
+  HeapFree(GetProcessHeap(), 0, qsc);
+
+  /* Get extended system details. */
+  if (service->startup == NSSM_STARTUP_AUTOMATIC) {
+    QueryServiceConfig2(service->handle, SERVICE_CONFIG_DELAYED_AUTO_START_INFO, 0, 0, &bufsize);
+    error = GetLastError();
+    if (error == ERROR_INSUFFICIENT_BUFFER) {
+      SERVICE_DELAYED_AUTO_START_INFO *info = (SERVICE_DELAYED_AUTO_START_INFO *) HeapAlloc(GetProcessHeap(), 0, bufsize);
+      if (! info) {
+        CloseHandle(service->handle);
+        CloseServiceHandle(services);
+        print_message(stderr, NSSM_EVENT_OUT_OF_MEMORY, _T("SERVICE_DELAYED_AUTO_START_INFO"), _T("pre_edit_service()"));
+        return 5;
+      }
+
+      if (QueryServiceConfig2(service->handle, SERVICE_CONFIG_DELAYED_AUTO_START_INFO, (unsigned char *) info, bufsize, &bufsize)) {
+        if (info->fDelayedAutostart) service->startup = NSSM_STARTUP_DELAYED;
+      }
+      else {
+        error = GetLastError();
+        if (error != ERROR_INVALID_LEVEL) {
+          CloseHandle(service->handle);
+          CloseServiceHandle(services);
+          print_message(stderr, NSSM_MESSAGE_QUERYSERVICECONFIG2_FAILED, service->name, _T("SERVICE_CONFIG_DELAYED_AUTO_START_INFO"), error_string(error));
+          return 5;
+        }
+      }
+    }
+    else if (error != ERROR_INVALID_LEVEL) {
+      CloseHandle(service->handle);
+      CloseServiceHandle(services);
+      print_message(stderr, NSSM_MESSAGE_QUERYSERVICECONFIG2_FAILED, service->name, _T("SERVICE_DELAYED_AUTO_START_INFO"), error_string(error));
+      return 5;
+    }
+  }
+
+  QueryServiceConfig2(service->handle, SERVICE_CONFIG_DESCRIPTION, 0, 0, &bufsize);
+  error = GetLastError();
+  if (error == ERROR_INSUFFICIENT_BUFFER) {
+    SERVICE_DESCRIPTION *description = (SERVICE_DESCRIPTION *) HeapAlloc(GetProcessHeap(), 0, bufsize);
+    if (! description) {
+      CloseHandle(service->handle);
+      CloseServiceHandle(services);
+      print_message(stderr, NSSM_EVENT_OUT_OF_MEMORY, _T("SERVICE_CONFIG_DESCRIPTION"), _T("pre_edit_service()"));
+      return 6;
+    }
+
+    if (QueryServiceConfig2(service->handle, SERVICE_CONFIG_DESCRIPTION, (unsigned char *) description, bufsize, &bufsize)) {
+     if (description->lpDescription) _sntprintf_s(service->description, _countof(service->description), _TRUNCATE, _T("%s"), description->lpDescription);
+      HeapFree(GetProcessHeap(), 0, description);
+    }
+    else {
+      HeapFree(GetProcessHeap(), 0, description);
+      CloseHandle(service->handle);
+      CloseServiceHandle(services);
+      print_message(stderr, NSSM_MESSAGE_QUERYSERVICECONFIG2_FAILED, service->name, _T("SERVICE_CONFIG_DELAYED_AUTO_START_INFO"), error_string(error));
+      return 6;
+    }
+  }
+  else {
+    CloseHandle(service->handle);
+    CloseServiceHandle(services);
+    print_message(stderr, NSSM_MESSAGE_QUERYSERVICECONFIG2_FAILED, service->name, _T("SERVICE_CONFIG_DELAYED_AUTO_START_INFO"), error_string(error));
+    return 6;
+  }
+
+  /* Get NSSM details. */
+  get_parameters(service, 0);
+
+  CloseServiceHandle(services);
+
+  if (! service->exe[0]) {
+    print_message(stderr, NSSM_MESSAGE_INVALID_SERVICE, service->name, NSSM, service->image);
+    service->native = true;
+  }
+
+  nssm_gui(IDD_EDIT, service);
+
+  return 0;
+}
+
 /* About to remove the service */
 int pre_remove_service(int argc, TCHAR **argv) {
   nssm_service_t *service = alloc_nssm_service();
@@ -150,8 +318,33 @@ int install_service(nssm_service_t *service) {
   }
 
   /* Get path of this program */
-  TCHAR command[MAX_PATH];
-  GetModuleFileName(0, command, _countof(command));
+  GetModuleFileName(0, service->image, _countof(service->image));
+
+  /* Create the service - settings will be changed in edit_service() */
+  service->handle = CreateService(services, service->name, service->name, SC_MANAGER_ALL_ACCESS, SERVICE_WIN32_OWN_PROCESS, SERVICE_AUTO_START, SERVICE_ERROR_NORMAL, service->image, 0, 0, 0, 0, 0);
+  if (! service->handle) {
+    print_message(stderr, NSSM_MESSAGE_CREATESERVICE_FAILED);
+    CloseServiceHandle(services);
+    return 5;
+  }
+
+  if (edit_service(service, false)) {
+    DeleteService(service->handle);
+    CloseServiceHandle(services);
+    return 6;
+  }
+
+  print_message(stdout, NSSM_MESSAGE_SERVICE_INSTALLED, service->name);
+
+  /* Cleanup */
+  CloseServiceHandle(services);
+
+  return 0;
+}
+
+/* Edit the service. */
+int edit_service(nssm_service_t *service, bool editing) {
+  if (! service) return 1;
 
   /*
     The only two valid flags for service type are SERVICE_WIN32_OWN_PROCESS
@@ -171,51 +364,59 @@ int install_service(nssm_service_t *service) {
   /* Display name. */
   if (! service->displayname[0]) _sntprintf_s(service->displayname, _countof(service->displayname), _TRUNCATE, _T("%s"), service->name);
 
-  /* Create the service */
-  service->handle = CreateService(services, service->name, service->displayname, SC_MANAGER_ALL_ACCESS, service->type, startup, SERVICE_ERROR_NORMAL, command, 0, 0, 0, service->username, service->password);
-  if (! service->handle) {
-    print_message(stderr, NSSM_MESSAGE_CREATESERVICE_FAILED);
-    CloseServiceHandle(services);
+  /*
+    Username must be NULL if we aren't changing or an account name.
+    We must explicitly user LOCALSYSTEM to change it when we are editing.
+    Password must be NULL if we aren't changing, a password or "".
+    Empty passwords are valid but we won't allow them in the GUI.
+  */
+  TCHAR *username = 0;
+  TCHAR *password = 0;
+  if (service->usernamelen) {
+    username = service->username;
+    if (service->passwordlen) password = service->password;
+    else password = _T("");
+  }
+  else if (editing) username = NSSM_LOCALSYSTEM_ACCOUNT;
+
+  if (! ChangeServiceConfig(service->handle, service->type, startup, SERVICE_NO_CHANGE, 0, 0, 0, 0, username, password, service->displayname)) {
+    print_message(stderr, NSSM_MESSAGE_CHANGESERVICECONFIG_FAILED, error_string(GetLastError()));
     return 5;
   }
 
-  if (service->description[0]) {
+  if (service->description[0] || editing) {
     SERVICE_DESCRIPTION description;
     ZeroMemory(&description, sizeof(description));
-    description.lpDescription = service->description;
+    if (service->description[0]) description.lpDescription = service->description;
+    else description.lpDescription = 0;
     if (! ChangeServiceConfig2(service->handle, SERVICE_CONFIG_DESCRIPTION, &description)) {
       log_event(EVENTLOG_ERROR_TYPE, NSSM_EVENT_SERVICE_CONFIG_DESCRIPTION_FAILED, service->name, error_string(GetLastError()), 0);
     }
   }
 
-  if (service->startup == NSSM_STARTUP_DELAYED) {
-    SERVICE_DELAYED_AUTO_START_INFO delayed;
-    ZeroMemory(&delayed, sizeof(delayed));
-    delayed.fDelayedAutostart = 1;
-    /* Delayed startup isn't supported until Vista. */
-    if (! ChangeServiceConfig2(service->handle, SERVICE_CONFIG_DELAYED_AUTO_START_INFO, &delayed)) {
-      unsigned long error = GetLastError();
-      /* Pre-Vista we expect to fail with ERROR_INVALID_LEVEL */
-      if (error != ERROR_INVALID_LEVEL) {
-        log_event(EVENTLOG_ERROR_TYPE, NSSM_EVENT_SERVICE_CONFIG_DELAYED_AUTO_START_INFO_FAILED, service->name, error_string(error), 0);
-      }
+  SERVICE_DELAYED_AUTO_START_INFO delayed;
+  ZeroMemory(&delayed, sizeof(delayed));
+  if (service->startup == NSSM_STARTUP_DELAYED) delayed.fDelayedAutostart = 1;
+  else delayed.fDelayedAutostart = 0;
+  /* Delayed startup isn't supported until Vista. */
+  if (! ChangeServiceConfig2(service->handle, SERVICE_CONFIG_DELAYED_AUTO_START_INFO, &delayed)) {
+    unsigned long error = GetLastError();
+    /* Pre-Vista we expect to fail with ERROR_INVALID_LEVEL */
+    if (error != ERROR_INVALID_LEVEL) {
+      log_event(EVENTLOG_ERROR_TYPE, NSSM_EVENT_SERVICE_CONFIG_DELAYED_AUTO_START_INFO_FAILED, service->name, error_string(error), 0);
     }
   }
 
-  /* Now we need to put the parameters into the registry */
-  if (create_parameters(service)) {
-    print_message(stderr, NSSM_MESSAGE_CREATE_PARAMETERS_FAILED);
-    DeleteService(service->handle);
-    CloseServiceHandle(services);
-    return 6;
-  }
-
-  set_service_recovery(service);
-
-  print_message(stdout, NSSM_MESSAGE_SERVICE_INSTALLED, service->name);
+  /* Don't mess with parameters which aren't ours. */
+  if (! service->native) {
+    /* Now we need to put the parameters into the registry */
+    if (create_parameters(service, editing)) {
+      print_message(stderr, NSSM_MESSAGE_CREATE_PARAMETERS_FAILED);
+      return 6;
+    }
 
-  /* Cleanup */
-  CloseServiceHandle(services);
+    set_service_recovery(service);
+  }
 
   return 0;
 }
@@ -295,7 +496,7 @@ void WINAPI service_main(unsigned long argc, TCHAR **argv) {
 
   if (is_admin) {
     /* Try to create the exit action parameters; we don't care if it fails */
-    create_exit_action(service->name, exit_action_strings[0]);
+    create_exit_action(service->name, exit_action_strings[0], false);
 
     SC_HANDLE services = open_service_manager();
     if (services) {
diff --git a/service.h b/service.h
index dc1715b..3460625 100644
--- a/service.h
+++ b/service.h
@@ -17,7 +17,10 @@
 
 #define ACTION_LEN 16
 
+#define NSSM_LOCALSYSTEM_ACCOUNT _T("LocalSystem")
+
 typedef struct {
+  bool native;
   TCHAR name[SERVICE_NAME_LENGTH];
   TCHAR displayname[SERVICE_DISPLAYNAME_LENGTH];
   TCHAR description[VALUE_LENGTH];
@@ -27,6 +30,7 @@ typedef struct {
   TCHAR *password;
   size_t passwordlen;
   unsigned long type;
+  TCHAR image[MAX_PATH];
   TCHAR exe[EXE_LENGTH];
   TCHAR flags[VALUE_LENGTH];
   TCHAR dir[MAX_PATH];
@@ -85,8 +89,10 @@ void cleanup_nssm_service(nssm_service_t *);
 SC_HANDLE open_service_manager();
 int pre_install_service(int, TCHAR **);
 int pre_remove_service(int, TCHAR **);
+int pre_edit_service(int, TCHAR **);
 int install_service(nssm_service_t *);
 int remove_service(nssm_service_t *);
+int edit_service(nssm_service_t *, bool);
 void set_service_recovery(nssm_service_t *);
 int monitor_service(nssm_service_t *);
 int start_service(nssm_service_t *);