Index: kern/loader.c
===================================================================
--- kern/loader.c	(revisión: 1845)
+++ kern/loader.c	(copia de trabajo)
@@ -22,12 +22,54 @@
 #include <grub/err.h>
 #include <grub/kernel.h>
 
+struct grub_preboot_t
+{
+  grub_err_t (*preboot_func) (int);  
+  struct grub_preboot_t *next;
+  struct grub_preboot_t *previous;
+};
+
 static grub_err_t (*grub_loader_boot_func) (void);
 static grub_err_t (*grub_loader_unload_func) (void);
 static int grub_loader_noreturn;
 
 static int grub_loader_loaded;
 
+static struct grub_preboot_t *grub_loader_preboots=0;
+
+void *
+grub_loader_add_preboot (grub_err_t (*preboot_func) (int))
+{
+  struct grub_preboot_t *cur;
+  if (!preboot_func)
+    return 0;
+  cur = (struct grub_preboot_t *) grub_malloc (sizeof (struct grub_preboot_t));
+  if (!cur)
+    {
+      grub_error (GRUB_ERR_OUT_OF_MEMORY, "no memory left to register hook");
+      return 0;
+    }
+  cur->next = grub_loader_preboots;
+  cur->previous = 0;
+  cur->next->previous = cur;
+  cur->preboot_func = preboot_func;
+  grub_loader_preboots = cur;
+  return cur;
+}
+
+void
+grub_loader_remove_preboot (void *p)
+{
+  struct grub_preboot_t *hnd = (struct grub_preboot_t *)p;
+  if (!hnd)
+    return;
+  if (hnd->previous)
+    hnd->previous->next = hnd->next;
+  if (hnd->next)
+    hnd->next->previous = hnd->previous;
+  grub_free (hnd);
+}
+
 int
 grub_loader_is_loaded (void)
 {
@@ -64,12 +106,18 @@
 grub_err_t
 grub_loader_boot (void)
 {
+  struct grub_preboot_t *iter=grub_loader_preboots;
   if (! grub_loader_loaded)
     return grub_error (GRUB_ERR_NO_KERNEL, "no loaded kernel");
 
   if (grub_loader_noreturn)
     grub_machine_fini ();
-  
+  while (iter)
+    {
+      if (iter->preboot_func)
+	iter->preboot_func (grub_loader_noreturn);
+      iter=iter->next;
+    }
   return (grub_loader_boot_func) ();
 }
 
Index: include/grub/loader.h
===================================================================
--- include/grub/loader.h	(revisión: 1845)
+++ include/grub/loader.h	(copia de trabajo)
@@ -25,6 +25,8 @@
 #include <grub/err.h>
 #include <grub/types.h>
 
+typedef grub_err_t (*grub_preboot_func) (int noreturn);
+
 /* Check if a loader is loaded.  */
 int EXPORT_FUNC(grub_loader_is_loaded) (void);
 
@@ -37,6 +39,12 @@
 /* Unset current loader, if any.  */
 void EXPORT_FUNC(grub_loader_unset) (void);
 
+/*Add a preboot function*/
+void* EXPORT_FUNC(grub_loader_add_preboot) (grub_preboot_func func);
+
+/*Remove given preboot function*/
+void EXPORT_FUNC(grub_loader_remove_preboot) (void *hnd);
+
 /* Call the boot hook in current loader. This may or may not return,
    depending on the setting by grub_loader_set.  */
 grub_err_t EXPORT_FUNC(grub_loader_boot) (void);