From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Mon, 26 Mar 2018 16:15:53 +0200
Subject: [PATCH] Accept ESC, F8 and holding SHIFT as user interrupt keys

On some devices the ESC key is the hotkey to enter the BIOS/EFI setup
screen, making it really hard to time pressing it right. Besides that
ESC is also pretty hard to discover for a user who does not know it
will unhide the menu.

This commit makes F8, which used to be the hotkey to show the Windows
boot menu during boot for a long long time, also interrupt sleeps /
stop the menu countdown.

This solves the ESC gets into the BIOS setup and also somewhat solves
the discoverability issue, but leaves the timing issue unresolved.

This commit fixes the timing issue by also adding support for keeping
SHIFT pressed during boot to stop the menu countdown. This matches
what Ubuntu is doing, which should also help with discoverability.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 grub-core/commands/sleep.c |  2 +-
 grub-core/kern/term.c      | 16 ++++++++++++++++
 grub-core/normal/menu.c    |  2 +-
 include/grub/term.h        |  1 +
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/grub-core/commands/sleep.c b/grub-core/commands/sleep.c
index e77e7900fac..a1370b710c9 100644
--- a/grub-core/commands/sleep.c
+++ b/grub-core/commands/sleep.c
@@ -55,7 +55,7 @@ grub_interruptible_millisleep (grub_uint32_t ms)
   start = grub_get_time_ms ();
 
   while (grub_get_time_ms () - start < ms)
-    if (grub_getkey_noblock () == GRUB_TERM_ESC)
+    if (grub_key_is_interrupt (grub_getkey_noblock ()))
       return 1;
 
   return 0;
diff --git a/grub-core/kern/term.c b/grub-core/kern/term.c
index 93bd3378d18..6cae4c23e7a 100644
--- a/grub-core/kern/term.c
+++ b/grub-core/kern/term.c
@@ -138,6 +138,22 @@ grub_getkeystatus (void)
   return status;
 }
 
+int
+grub_key_is_interrupt (int key)
+{
+  /* ESC sometimes is the BIOS setup hotkey and may be hard to discover, also
+     check F8, which was the key to get the Windows bootmenu for a long time. */
+  if (key == GRUB_TERM_ESC || key == GRUB_TERM_KEY_F8)
+    return 1;
+
+  /* Pressing keys at the right time during boot is hard to time, also allow
+     interrupting sleeps / the menu countdown by keeping shift pressed. */
+  if (grub_getkeystatus() & (GRUB_TERM_STATUS_LSHIFT|GRUB_TERM_STATUS_RSHIFT))
+    return 1;
+
+  return 0;
+}
+
 void
 grub_refresh (void)
 {
diff --git a/grub-core/normal/menu.c b/grub-core/normal/menu.c
index 5e2f5283d3d..6cb2a071490 100644
--- a/grub-core/normal/menu.c
+++ b/grub-core/normal/menu.c
@@ -655,7 +655,7 @@ run_menu (grub_menu_t menu, int nested, int *auto_boot)
 	      if (entry >= 0)
 		break;
 	    }
-	  if (key == GRUB_TERM_ESC)
+	  if (grub_key_is_interrupt (key))
 	    {
 	      timeout = -1;
 	      break;
diff --git a/include/grub/term.h b/include/grub/term.h
index c215133383f..2b079c29b80 100644
--- a/include/grub/term.h
+++ b/include/grub/term.h
@@ -328,6 +328,7 @@ void grub_putcode (grub_uint32_t code, struct grub_term_output *term);
 int EXPORT_FUNC(grub_getkey) (void);
 int EXPORT_FUNC(grub_getkey_noblock) (void);
 int EXPORT_FUNC(grub_getkeystatus) (void);
+int EXPORT_FUNC(grub_key_is_interrupt) (int key);
 void grub_cls (void);
 void EXPORT_FUNC(grub_refresh) (void);
 void grub_puts_terminal (const char *str, struct grub_term_output *term);