Normally, GRUB allows using a combination of the Return/Enter (`\n' and
`\r'), Ctrl-F, and the right arrow key to select a menu item. However, on
some keyboards (especially those half-height arrow keys found on laptop
computers), it is very easy to accidentally select a menu item when the
user meant to press the up/down arrow key.
Implement an GRUB_RIGHT_TO_SELECT option (boolean) to enable/disable right
arrow key for selecting menu items.
---
Changes in v2:
* Fix comment style.
* Fix if condition styling for TERM_KEY_RIGHT detection (Avnish: I kept
the indentation style, as it's consistent with the styling in the
TERM_KEY_ESC case below, in how those indentations were written for
that if-and-break branch).
Co-developed-by: Mag Mell <sakii...@aosc.io>
Signed-off-by: Mingcong Bai <jeff...@aosc.io>
---
docs/grub.texi | 4 ++++
grub-core/normal/menu.c | 23 ++++++++++++++++++++---
util/grub-mkconfig.in | 3 ++-
util/grub.d/00_header.in | 6 ++++++
4 files changed, 32 insertions(+), 4 deletions(-)
diff --git a/docs/grub.texi b/docs/grub.texi
index a225f9a88..09d251659 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -1596,6 +1596,10 @@ This option may be set to a list of GRUB module names
separated by spaces.
Each module will be loaded as early as possible, at the start of
@file{grub.cfg}.
+@item GRUB_RIGHT_TO_SELECT
+This option may be set to specify whether the right arrow key may be used
+to make a selection. This option defaults to @samp{true}.
+
@end table
The following options are still accepted for compatibility with existing
diff --git a/grub-core/normal/menu.c b/grub-core/normal/menu.c
index 6a90e091f..d54e5a53b 100644
--- a/grub-core/normal/menu.c
+++ b/grub-core/normal/menu.c
@@ -32,6 +32,7 @@
#include <grub/script_sh.h>
#include <grub/gfxterm.h>
#include <grub/dl.h>
+#include <grub/env.h>
/* Time to delay after displaying an error message about a default/fallback
entry failing to boot. */
@@ -579,11 +580,18 @@ run_menu (grub_menu_t menu, int nested, int *auto_boot,
int *notify_boot)
int default_entry, current_entry;
int timeout;
enum timeout_style timeout_style;
+ bool right_to_select;
*notify_boot = 1;
default_entry = get_entry_number (menu, "default");
+ /*
+ * Read if the right arrow key is enabled for selection. Default to `true'
+ * if unset.
+ */
+ right_to_select = grub_env_get_bool ("right_to_select", true);
+
/* If DEFAULT_ENTRY is not within the menu entries, fall back to
the first entry. */
if (default_entry < 0 || default_entry >= menu->size)
@@ -762,9 +770,18 @@ run_menu (grub_menu_t menu, int nested, int *auto_boot,
int *notify_boot)
case '\r':
case GRUB_TERM_KEY_RIGHT:
case GRUB_TERM_CTRL | 'f':
- menu_fini ();
- *auto_boot = 0;
- return current_entry;
+ /*
+ * Right arrow key to select only when boolean value
+ * `right_to_select' is set to `true' or not specified
+ * (defaults to `true').
+ */
+ if ((c != GRUB_TERM_KEY_RIGHT) || right_to_select)
+ {
+ menu_fini ();
+ *auto_boot = 0;
+ return current_entry;
+ }
+ break;
case GRUB_TERM_ESC:
if (nested)
diff --git a/util/grub-mkconfig.in b/util/grub-mkconfig.in
index 32c480dae..d0e0efbb1 100644
--- a/util/grub-mkconfig.in
+++ b/util/grub-mkconfig.in
@@ -255,7 +255,8 @@ export GRUB_DEFAULT \
GRUB_ENABLE_CRYPTODISK \
GRUB_BADRAM \
GRUB_OS_PROBER_SKIP_LIST \
- GRUB_DISABLE_SUBMENU
+ GRUB_DISABLE_SUBMENU \
+ GRUB_RIGHT_TO_SELECT
if test "x${grub_cfg}" != "x"; then
rm -f "${grub_cfg}.new"
diff --git a/util/grub.d/00_header.in b/util/grub.d/00_header.in
index 6a316a5ba..54b2f9aa7 100644
--- a/util/grub.d/00_header.in
+++ b/util/grub.d/00_header.in
@@ -37,6 +37,7 @@ if [ "x${GRUB_DEFAULT}" = "x" ] ; then GRUB_DEFAULT=0 ; fi
if [ "x${GRUB_DEFAULT}" = "xsaved" ] ; then GRUB_DEFAULT='${saved_entry}' ; fi
if [ "x${GRUB_TIMEOUT}" = "x" ] ; then GRUB_TIMEOUT=5 ; fi
if [ "x${GRUB_GFXMODE}" = "x" ] ; then GRUB_GFXMODE=auto ; fi
+if [ "x${GRUB_RIGHT_TO_SELECT}" = "x" ] ; then GRUB_RIGHT_TO_SELECT=true ; fi
if [ "x${GRUB_DEFAULT_BUTTON}" = "x" ] ; then
GRUB_DEFAULT_BUTTON="$GRUB_DEFAULT" ; fi
if [ "x${GRUB_DEFAULT_BUTTON}" = "xsaved" ] ; then
GRUB_DEFAULT_BUTTON='${saved_entry}' ; fi
@@ -354,3 +355,8 @@ fi
if [ "x${GRUB_BADRAM}" != "x" ] ; then
echo "badram ${GRUB_BADRAM}"
fi
+
+# Whether to allow selecting with the right arrow key.
+cat << EOF
+set right_to_select=${GRUB_RIGHT_TO_SELECT}
+EOF
--
2.47.0
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