initial commit

GRUB2/grub-2.04/grub-core/normal/menu.c

@@ -0,0 +1,913 @@
+/* menu.c - General supporting functionality for menus.  */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2003,2004,2005,2006,2007,2008,2009,2010  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/normal.h>
+#include <grub/misc.h>
+#include <grub/loader.h>
+#include <grub/mm.h>
+#include <grub/time.h>
+#include <grub/env.h>
+#include <grub/menu_viewer.h>
+#include <grub/command.h>
+#include <grub/parser.h>
+#include <grub/auth.h>
+#include <grub/i18n.h>
+#include <grub/term.h>
+#include <grub/script_sh.h>
+#include <grub/gfxterm.h>
+#include <grub/dl.h>
+
+/* Time to delay after displaying an error message about a default/fallback
+   entry failing to boot.  */
+#define DEFAULT_ENTRY_ERROR_DELAY_MS  2500
+
+grub_err_t (*grub_gfxmenu_try_hook) (int entry, grub_menu_t menu,
+				     int nested) = NULL;
+
+enum timeout_style {
+  TIMEOUT_STYLE_MENU,
+  TIMEOUT_STYLE_COUNTDOWN,
+  TIMEOUT_STYLE_HIDDEN
+};
+
+struct timeout_style_name {
+  const char *name;
+  enum timeout_style style;
+} timeout_style_names[] = {
+  {"menu", TIMEOUT_STYLE_MENU},
+  {"countdown", TIMEOUT_STYLE_COUNTDOWN},
+  {"hidden", TIMEOUT_STYLE_HIDDEN},
+  {NULL, 0}
+};
+
+/* Wait until the user pushes any key so that the user
+   can see what happened.  */
+void
+grub_wait_after_message (void)
+{
+  grub_uint64_t endtime;
+  grub_xputs ("\n");
+  grub_printf_ (N_("Press any key to continue..."));
+  grub_refresh ();
+
+  endtime = grub_get_time_ms () + 10000;
+
+  while (grub_get_time_ms () < endtime
+	 && grub_getkey_noblock () == GRUB_TERM_NO_KEY);
+
+  grub_xputs ("\n");
+}
+
+/* Get a menu entry by its index in the entry list.  */
+grub_menu_entry_t
+grub_menu_get_entry (grub_menu_t menu, int no)
+{
+  grub_menu_entry_t e;
+
+  for (e = menu->entry_list; e && no > 0; e = e->next, no--)
+    ;
+
+  return e;
+}
+
+/* Get the index of a menu entry associated with a given hotkey, or -1.  */
+static int
+get_entry_index_by_hotkey (grub_menu_t menu, int hotkey)
+{
+  grub_menu_entry_t entry;
+  int i;
+
+  for (i = 0, entry = menu->entry_list; i < menu->size;
+       i++, entry = entry->next)
+    if (entry->hotkey == hotkey)
+      return i;
+
+  return -1;
+}
+
+/* Return the timeout style.  If the variable "timeout_style" is not set or
+   invalid, default to TIMEOUT_STYLE_MENU.  */
+static enum timeout_style
+get_timeout_style (void)
+{
+  const char *val;
+  struct timeout_style_name *style_name;
+
+  val = grub_env_get ("timeout_style");
+  if (!val)
+    return TIMEOUT_STYLE_MENU;
+
+  for (style_name = timeout_style_names; style_name->name; style_name++)
+    if (grub_strcmp (style_name->name, val) == 0)
+      return style_name->style;
+
+  return TIMEOUT_STYLE_MENU;
+}
+
+/* Return the current timeout. If the variable "timeout" is not set or
+   invalid, return -1.  */
+int
+grub_menu_get_timeout (void)
+{
+  const char *val;
+  int timeout;
+
+  val = grub_env_get ("timeout");
+  if (! val)
+    return -1;
+
+  grub_error_push ();
+
+  timeout = (int) grub_strtoul (val, 0, 0);
+
+  /* If the value is invalid, unset the variable.  */
+  if (grub_errno != GRUB_ERR_NONE)
+    {
+      grub_env_unset ("timeout");
+      grub_errno = GRUB_ERR_NONE;
+      timeout = -1;
+    }
+
+  grub_error_pop ();
+
+  return timeout;
+}
+
+/* Set current timeout in the variable "timeout".  */
+void
+grub_menu_set_timeout (int timeout)
+{
+  /* Ignore TIMEOUT if it is zero, because it will be unset really soon.  */
+  if (timeout > 0)
+    {
+      char buf[16];
+
+      grub_snprintf (buf, sizeof (buf), "%d", timeout);
+      grub_env_set ("timeout", buf);
+    }
+}
+
+/* Get the first entry number from the value of the environment variable NAME,
+   which is a space-separated list of non-negative integers.  The entry number
+   which is returned is stripped from the value of NAME.  If no entry number
+   can be found, -1 is returned.  */
+static int
+get_and_remove_first_entry_number (const char *name)
+{
+  const char *val;
+  char *tail;
+  int entry;
+
+  val = grub_env_get (name);
+  if (! val)
+    return -1;
+
+  grub_error_push ();
+
+  entry = (int) grub_strtoul (val, &tail, 0);
+
+  if (grub_errno == GRUB_ERR_NONE)
+    {
+      /* Skip whitespace to find the next digit.  */
+      while (*tail && grub_isspace (*tail))
+	tail++;
+      grub_env_set (name, tail);
+    }
+  else
+    {
+      grub_env_unset (name);
+      grub_errno = GRUB_ERR_NONE;
+      entry = -1;
+    }
+
+  grub_error_pop ();
+
+  return entry;
+}
+
+/* Run a menu entry.  */
+static void
+grub_menu_execute_entry(grub_menu_entry_t entry, int auto_boot)
+{
+  grub_err_t err = GRUB_ERR_NONE;
+  int errs_before;
+  grub_menu_t menu = NULL;
+  char *optr, *buf, *oldchosen = NULL, *olddefault = NULL;
+  const char *ptr, *chosen, *def;
+  grub_size_t sz = 0;
+
+  if (entry->restricted)
+    err = grub_auth_check_authentication (entry->users);
+
+  if (err)
+    {
+      grub_print_error ();
+      grub_errno = GRUB_ERR_NONE;
+      return;
+    }
+
+  errs_before = grub_err_printed_errors;
+
+  chosen = grub_env_get ("chosen");
+  def = grub_env_get ("default");
+
+  if (entry->submenu)
+    {
+      grub_env_context_open ();
+      menu = grub_zalloc (sizeof (*menu));
+      if (! menu)
+	return;
+      grub_env_set_menu (menu);
+      if (auto_boot)
+	grub_env_set ("timeout", "0");
+    }
+
+  for (ptr = entry->id; *ptr; ptr++)
+    sz += (*ptr == '>') ? 2 : 1;
+  if (chosen)
+    {
+      oldchosen = grub_strdup (chosen);
+      if (!oldchosen)
+	grub_print_error ();
+    }
+  if (def)
+    {
+      olddefault = grub_strdup (def);
+      if (!olddefault)
+	grub_print_error ();
+    }
+  sz++;
+  if (chosen)
+    sz += grub_strlen (chosen);
+  sz++;
+  buf = grub_malloc (sz);
+  if (!buf)
+    grub_print_error ();
+  else
+    {
+      optr = buf;
+      if (chosen)
+	{
+	  optr = grub_stpcpy (optr, chosen);
+	  *optr++ = '>';
+	}
+      for (ptr = entry->id; *ptr; ptr++)
+	{
+	  if (*ptr == '>')
+	    *optr++ = '>';
+	  *optr++ = *ptr;
+	}
+      *optr = 0;
+      grub_env_set ("chosen", buf);
+      grub_env_export ("chosen");
+      grub_free (buf);
+    }
+
+  for (ptr = def; ptr && *ptr; ptr++)
+    {
+      if (ptr[0] == '>' && ptr[1] == '>')
+	{
+	  ptr++;
+	  continue;
+	}
+      if (ptr[0] == '>')
+	break;
+    }
+
+  if (ptr && ptr[0] && ptr[1])
+    grub_env_set ("default", ptr + 1);
+  else
+    grub_env_unset ("default");
+
+  grub_script_execute_new_scope (entry->sourcecode, entry->argc, entry->args);
+
+  if (errs_before != grub_err_printed_errors)
+    grub_wait_after_message ();
+
+  errs_before = grub_err_printed_errors;
+
+  if (grub_errno == GRUB_ERR_NONE && grub_loader_is_loaded ())
+    /* Implicit execution of boot, only if something is loaded.  */
+    grub_command_execute ("boot", 0, 0);
+
+  if (errs_before != grub_err_printed_errors)
+    grub_wait_after_message ();
+
+  if (entry->submenu)
+    {
+      if (menu && menu->size)
+	{
+	  grub_show_menu (menu, 1, auto_boot);
+	  grub_normal_free_menu (menu);
+	}
+      grub_env_context_close ();
+    }
+  if (oldchosen)
+    grub_env_set ("chosen", oldchosen);
+  else
+    grub_env_unset ("chosen");
+  if (olddefault)
+    grub_env_set ("default", olddefault);
+  else
+    grub_env_unset ("default");
+  grub_env_unset ("timeout");
+}
+
+/* Execute ENTRY from the menu MENU, falling back to entries specified
+   in the environment variable "fallback" if it fails.  CALLBACK is a
+   pointer to a struct of function pointers which are used to allow the
+   caller provide feedback to the user.  */
+static void
+grub_menu_execute_with_fallback (grub_menu_t menu,
+				 grub_menu_entry_t entry,
+				 int autobooted,
+				 grub_menu_execute_callback_t callback,
+				 void *callback_data)
+{
+  int fallback_entry;
+
+  callback->notify_booting (entry, callback_data);
+
+  grub_menu_execute_entry (entry, 1);
+
+  /* Deal with fallback entries.  */
+  while ((fallback_entry = get_and_remove_first_entry_number ("fallback"))
+	 >= 0)
+    {
+      grub_print_error ();
+      grub_errno = GRUB_ERR_NONE;
+
+      entry = grub_menu_get_entry (menu, fallback_entry);
+      callback->notify_fallback (entry, callback_data);
+      grub_menu_execute_entry (entry, 1);
+      /* If the function call to execute the entry returns at all, then this is
+	 taken to indicate a boot failure.  For menu entries that do something
+	 other than actually boot an operating system, this could assume
+	 incorrectly that something failed.  */
+    }
+
+  if (!autobooted)
+    callback->notify_failure (callback_data);
+}
+
+static struct grub_menu_viewer *viewers;
+
+static void
+menu_set_chosen_entry (int entry)
+{
+  struct grub_menu_viewer *cur;
+  for (cur = viewers; cur; cur = cur->next)
+    cur->set_chosen_entry (entry, cur->data);
+}
+
+static void
+menu_print_timeout (int timeout)
+{
+  struct grub_menu_viewer *cur;
+  for (cur = viewers; cur; cur = cur->next)
+    cur->print_timeout (timeout, cur->data);
+}
+
+static void
+menu_fini (void)
+{
+  struct grub_menu_viewer *cur, *next;
+  for (cur = viewers; cur; cur = next)
+    {
+      next = cur->next;
+      cur->fini (cur->data);
+      grub_free (cur);
+    }
+  viewers = NULL;
+}
+
+static void
+menu_init (int entry, grub_menu_t menu, int nested)
+{
+  struct grub_term_output *term;
+  int gfxmenu = 0;
+
+  FOR_ACTIVE_TERM_OUTPUTS(term)
+    if (term->fullscreen)
+      {
+	if (grub_env_get ("theme"))
+	  {
+	    if (!grub_gfxmenu_try_hook)
+	      {
+		grub_dl_load ("gfxmenu");
+		grub_print_error ();
+	      }
+	    if (grub_gfxmenu_try_hook)
+	      {
+		grub_err_t err;
+		err = grub_gfxmenu_try_hook (entry, menu, nested);
+		if(!err)
+		  {
+		    gfxmenu = 1;
+		    break;
+		  }
+	      }
+	    else
+	      grub_error (GRUB_ERR_BAD_MODULE,
+			  N_("module `%s' isn't loaded"),
+			  "gfxmenu");
+	    grub_print_error ();
+	    grub_wait_after_message ();
+	  }
+	grub_errno = GRUB_ERR_NONE;
+	term->fullscreen ();
+	break;
+      }
+
+  FOR_ACTIVE_TERM_OUTPUTS(term)
+  {
+    grub_err_t err;
+
+    if (grub_strcmp (term->name, "gfxterm") == 0 && gfxmenu)
+      continue;
+
+    err = grub_menu_try_text (term, entry, menu, nested);
+    if(!err)
+      continue;
+    grub_print_error ();
+    grub_errno = GRUB_ERR_NONE;
+  }
+}
+
+static void
+clear_timeout (void)
+{
+  struct grub_menu_viewer *cur;
+  for (cur = viewers; cur; cur = cur->next)
+    cur->clear_timeout (cur->data);
+}
+
+void
+grub_menu_register_viewer (struct grub_menu_viewer *viewer)
+{
+  viewer->next = viewers;
+  viewers = viewer;
+}
+
+static int
+menuentry_eq (const char *id, const char *spec)
+{
+  const char *ptr1, *ptr2;
+  ptr1 = id;
+  ptr2 = spec;
+  while (1)
+    {
+      if (*ptr2 == '>' && ptr2[1] != '>' && *ptr1 == 0)
+	return 1;
+      if (*ptr2 == '>' && ptr2[1] != '>')
+	return 0;
+      if (*ptr2 == '>')
+	ptr2++;
+      if (*ptr1 != *ptr2)
+	return 0;
+      if (*ptr1 == 0)
+	return 1;
+      ptr1++;
+      ptr2++;
+    }
+}
+
+
+/* Get the entry number from the variable NAME.  */
+static int
+get_entry_number (grub_menu_t menu, const char *name)
+{
+  const char *val;
+  int entry;
+
+  val = grub_env_get (name);
+  if (! val)
+    return -1;
+
+  grub_error_push ();
+
+  entry = (int) grub_strtoul (val, 0, 0);
+
+  if (grub_errno == GRUB_ERR_BAD_NUMBER)
+    {
+      /* See if the variable matches the title of a menu entry.  */
+      grub_menu_entry_t e = menu->entry_list;
+      int i;
+
+      grub_errno = GRUB_ERR_NONE;
+
+      for (i = 0; e; i++)
+	{
+	  if (menuentry_eq (e->title, val)
+	      || menuentry_eq (e->id, val))
+	    {
+	      entry = i;
+	      break;
+	    }
+	  e = e->next;
+	}
+
+      if (! e)
+	entry = -1;
+    }
+
+  if (grub_errno != GRUB_ERR_NONE)
+    {
+      grub_errno = GRUB_ERR_NONE;
+      entry = -1;
+    }
+
+  grub_error_pop ();
+
+  return entry;
+}
+
+/* Check whether a second has elapsed since the last tick.  If so, adjust
+   the timer and return 1; otherwise, return 0.  */
+static int
+has_second_elapsed (grub_uint64_t *saved_time)
+{
+  grub_uint64_t current_time;
+
+  current_time = grub_get_time_ms ();
+  if (current_time - *saved_time >= 1000)
+    {
+      *saved_time = current_time;
+      return 1;
+    }
+  else
+    return 0;
+}
+
+static void
+print_countdown (struct grub_term_coordinate *pos, int n)
+{
+  grub_term_restore_pos (pos);
+  /* NOTE: Do not remove the trailing space characters.
+     They are required to clear the line.  */
+  grub_printf ("%d    ", n);
+  grub_refresh ();
+}
+
+#define GRUB_MENU_PAGE_SIZE 10
+
+/* Show the menu and handle menu entry selection.  Returns the menu entry
+   index that should be executed or -1 if no entry should be executed (e.g.,
+   Esc pressed to exit a sub-menu or switching menu viewers).
+   If the return value is not -1, then *AUTO_BOOT is nonzero iff the menu
+   entry to be executed is a result of an automatic default selection because
+   of the timeout.  */
+static int
+run_menu (grub_menu_t menu, int nested, int *auto_boot)
+{
+  grub_uint64_t saved_time;
+  int default_entry, current_entry;
+  int timeout;
+  enum timeout_style timeout_style;
+
+  default_entry = get_entry_number (menu, "default");
+
+  /* If DEFAULT_ENTRY is not within the menu entries, fall back to
+     the first entry.  */
+  if (default_entry < 0 || default_entry >= menu->size)
+    default_entry = 0;
+
+  timeout = grub_menu_get_timeout ();
+  if (timeout < 0)
+    /* If there is no timeout, the "countdown" and "hidden" styles result in
+       the system doing nothing and providing no or very little indication
+       why.  Technically this is what the user asked for, but it's not very
+       useful and likely to be a source of confusion, so we disallow this.  */
+    grub_env_unset ("timeout_style");
+
+  timeout_style = get_timeout_style ();
+
+  if (timeout_style == TIMEOUT_STYLE_COUNTDOWN
+      || timeout_style == TIMEOUT_STYLE_HIDDEN)
+    {
+      static struct grub_term_coordinate *pos;
+      int entry = -1;
+
+      if (timeout_style == TIMEOUT_STYLE_COUNTDOWN && timeout)
+	{
+	  pos = grub_term_save_pos ();
+	  print_countdown (pos, timeout);
+	}
+
+      /* Enter interruptible sleep until Escape or a menu hotkey is pressed,
+         or the timeout expires.  */
+      saved_time = grub_get_time_ms ();
+      while (1)
+	{
+	  int key;
+
+	  key = grub_getkey_noblock ();
+	  if (key != GRUB_TERM_NO_KEY)
+	    {
+	      entry = get_entry_index_by_hotkey (menu, key);
+	      if (entry >= 0)
+		break;
+	    }
+	  if (key == GRUB_TERM_ESC)
+	    {
+	      timeout = -1;
+	      break;
+	    }
+
+	  if (timeout > 0 && has_second_elapsed (&saved_time))
+	    {
+	      timeout--;
+	      if (timeout_style == TIMEOUT_STYLE_COUNTDOWN)
+		print_countdown (pos, timeout);
+	    }
+
+	  if (timeout == 0)
+	    /* We will fall through to auto-booting the default entry.  */
+	    break;
+	}
+
+      grub_env_unset ("timeout");
+      grub_env_unset ("timeout_style");
+      if (entry >= 0)
+	{
+	  *auto_boot = 0;
+	  return entry;
+	}
+    }
+
+  /* If timeout is 0, drawing is pointless (and ugly).  */
+  if (timeout == 0)
+    {
+      *auto_boot = 1;
+      return default_entry;
+    }
+
+  current_entry = default_entry;
+
+ refresh:
+  menu_init (current_entry, menu, nested);
+
+  /* Initialize the time.  */
+  saved_time = grub_get_time_ms ();
+
+  timeout = grub_menu_get_timeout ();
+
+  if (timeout > 0)
+    menu_print_timeout (timeout);
+  else
+    clear_timeout ();
+
+  while (1)
+    {
+      int c;
+      timeout = grub_menu_get_timeout ();
+
+      if (grub_normal_exit_level)
+	return -1;
+
+      if (timeout > 0 && has_second_elapsed (&saved_time))
+	{
+	  timeout--;
+	  grub_menu_set_timeout (timeout);
+	  menu_print_timeout (timeout);
+	}
+
+      if (timeout == 0)
+	{
+	  grub_env_unset ("timeout");
+          *auto_boot = 1;
+	  menu_fini ();
+	  return default_entry;
+	}
+
+      c = grub_getkey_noblock ();
+
+      /* Negative values are returned on error. */
+      if ((c != GRUB_TERM_NO_KEY) && (c > 0))
+	{
+	  if (timeout >= 0)
+	    {
+	      grub_env_unset ("timeout");
+	      grub_env_unset ("fallback");
+	      clear_timeout ();
+	    }
+
+	  switch (c)
+	    {
+	    case GRUB_TERM_KEY_HOME:
+	    case GRUB_TERM_CTRL | 'a':
+	      current_entry = 0;
+	      menu_set_chosen_entry (current_entry);
+	      break;
+
+	    case GRUB_TERM_KEY_END:
+	    case GRUB_TERM_CTRL | 'e':
+	      current_entry = menu->size - 1;
+	      menu_set_chosen_entry (current_entry);
+	      break;
+
+	    case GRUB_TERM_KEY_UP:
+	    case GRUB_TERM_CTRL | 'p':
+	    case '^':
+	      if (current_entry > 0)
+		current_entry--;
+	      menu_set_chosen_entry (current_entry);
+	      break;
+
+	    case GRUB_TERM_CTRL | 'n':
+	    case GRUB_TERM_KEY_DOWN:
+	    case 'v':
+	      if (current_entry < menu->size - 1)
+		current_entry++;
+	      menu_set_chosen_entry (current_entry);
+	      break;
+
+	    case GRUB_TERM_CTRL | 'g':
+	    case GRUB_TERM_KEY_PPAGE:
+	      if (current_entry < GRUB_MENU_PAGE_SIZE)
+		current_entry = 0;
+	      else
+		current_entry -= GRUB_MENU_PAGE_SIZE;
+	      menu_set_chosen_entry (current_entry);
+	      break;
+
+	    case GRUB_TERM_CTRL | 'c':
+	    case GRUB_TERM_KEY_NPAGE:
+	      if (current_entry + GRUB_MENU_PAGE_SIZE < menu->size)
+		current_entry += GRUB_MENU_PAGE_SIZE;
+	      else
+		current_entry = menu->size - 1;
+	      menu_set_chosen_entry (current_entry);
+	      break;
+
+	    case '\n':
+	    case '\r':
+	//    case GRUB_TERM_KEY_RIGHT:
+	    case GRUB_TERM_CTRL | 'f':
+	      menu_fini ();
+              *auto_boot = 0;
+	      return current_entry;
+
+	    case GRUB_TERM_ESC:
+	      if (nested)
+		{
+		  menu_fini ();
+		  return -1;
+		}
+	      break;
+
+	    case 'c':
+	      menu_fini ();
+	      grub_cmdline_run (1, 0);
+	      goto refresh;
+
+	    case 'e':
+	      menu_fini ();
+		{
+		  grub_menu_entry_t e = grub_menu_get_entry (menu, current_entry);
+		  if (e)
+		    grub_menu_entry_run (e);
+		}
+	      goto refresh;
+
+	    default:
+	      {
+		int entry;
+
+		entry = get_entry_index_by_hotkey (menu, c);
+		if (entry >= 0)
+		  {
+		    menu_fini ();
+		    *auto_boot = 0;
+		    return entry;
+		  }
+	      }
+	      break;
+	    }
+	}
+    }
+
+  /* Never reach here.  */
+}
+
+/* Callback invoked immediately before a menu entry is executed.  */
+static void
+notify_booting (grub_menu_entry_t entry,
+		void *userdata __attribute__((unused)))
+{
+  grub_printf ("  ");
+  grub_printf_ (N_("Booting `%s'"), entry->title);
+  grub_printf ("\n\n");
+}
+
+/* Callback invoked when a default menu entry executed because of a timeout
+   has failed and an attempt will be made to execute the next fallback
+   entry, ENTRY.  */
+static void
+notify_fallback (grub_menu_entry_t entry,
+		 void *userdata __attribute__((unused)))
+{
+  grub_printf ("\n   ");
+  grub_printf_ (N_("Falling back to `%s'"), entry->title);
+  grub_printf ("\n\n");
+  grub_millisleep (DEFAULT_ENTRY_ERROR_DELAY_MS);
+}
+
+/* Callback invoked when a menu entry has failed and there is no remaining
+   fallback entry to attempt.  */
+static void
+notify_execution_failure (void *userdata __attribute__((unused)))
+{
+  if (grub_errno != GRUB_ERR_NONE)
+    {
+      grub_print_error ();
+      grub_errno = GRUB_ERR_NONE;
+    }
+  grub_printf ("\n  ");
+  grub_printf_ (N_("Failed to boot both default and fallback entries.\n"));
+  grub_wait_after_message ();
+}
+
+/* Callbacks used by the text menu to provide user feedback when menu entries
+   are executed.  */
+static struct grub_menu_execute_callback execution_callback =
+{
+  .notify_booting = notify_booting,
+  .notify_fallback = notify_fallback,
+  .notify_failure = notify_execution_failure
+};
+
+static grub_err_t
+show_menu (grub_menu_t menu, int nested, int autobooted)
+{
+  while (1)
+    {
+      int boot_entry;
+      grub_menu_entry_t e;
+      int auto_boot;
+
+      boot_entry = run_menu (menu, nested, &auto_boot);
+      if (boot_entry < 0)
+	break;
+
+      e = grub_menu_get_entry (menu, boot_entry);
+      if (! e)
+	continue; /* Menu is empty.  */
+
+      grub_cls ();
+
+      if (auto_boot)
+	grub_menu_execute_with_fallback (menu, e, autobooted,
+					 &execution_callback, 0);
+      else
+	grub_menu_execute_entry (e, 0);
+      if (autobooted)
+	break;
+    }
+
+  return GRUB_ERR_NONE;
+}
+
+grub_err_t
+grub_show_menu (grub_menu_t menu, int nested, int autoboot)
+{
+  grub_err_t err1, err2;
+
+  while (1)
+    {
+      err1 = show_menu (menu, nested, autoboot);
+      autoboot = 0;
+      grub_print_error ();
+
+      if (grub_normal_exit_level)
+	break;
+
+      err2 = grub_auth_check_authentication (NULL);
+      if (err2)
+	{
+	  grub_print_error ();
+	  grub_errno = GRUB_ERR_NONE;
+	  continue;
+	}
+
+      break;
+    }
+
+  return err1;
+}