[PATCH] bootmenu: Allow to quit it via CTRL+C

[Heinrich Schuchardt]

Am 26. Dezember 2020 20:15:40 MEZ schrieb "Pali Rohár" <pali at kernel.org>:
>On Saturday 26 December 2020 20:10:10 Heinrich Schuchardt wrote:
>> Am 26. Dezember 2020 20:03:56 MEZ schrieb "Pali Rohár"
><pali at kernel.org>:
>> >On Saturday 26 December 2020 19:44:23 Heinrich Schuchardt wrote:
>> >> Am 26. Dezember 2020 19:02:25 MEZ schrieb "Pali Rohár"
>> ><pali at kernel.org>:
>> >> >When CTRL+C is pressed interrupt bootmenu and jump into U-Boot
>> >console.
>> >> >As the last entry in bootmenu is always U-Boot console just
>choose
>> >the
>> >> >last
>> >> >entry when CTRL+C is pressed.
>> >> >
>> >> >It is useful when bootmenu is part of boot process and you want
>to
>> >> >interrupt boot process by scripts which control U-Boot (serial)
>> >> >console.
>> >> 
>> >> Wouldn't the escape key be a better choice?
>> >
>> >I can add also escape key. But has escape key stable ANSI sequence
>> >which
>> >is needed to catch? If you tell me which bytes to catch (for escape
>> >key)
>> >I will add it.
>> 
>> 0x1b is Escape
>
>Does not work. 0x1b is not escape key. It is start of the ANSI escape
>sequence which matches also existing keys up and down.

On the serial console you have to hit the key twice.

The device driver will tranlate it to a single 0x1b which is the char you want to react to.

>
>> >
>> >> On the sandbox CTRL-C makes you quit U-Boot.
>> >> 
>> >> When hitting CTRL-C late on other systems it might interrupt a
>> >follow-up command.
>> >
>> >I understand your concerns. But all other commands catch also CTRL+C
>so
>> >I think that bootmenu command should it too.
>> >
>> >> --
>> >> 
>> >> The following is not directly related to your patch:
>> >> 
>> >> Is it really a good design that a user cannot be stopped from
>> >reaching the console?
>> >
>> >Currently "U-Boot console" option is always added to menu list. But
>> >option is doing only one thing: exiting the current U-Boot command
>and
>> >returning back to the monitor mode.
>> >
>> >> I could think of use cases in the context of secure booting where
>you
>> >want to show a menu but you do not want to give access to the
>command
>> >line.
>> >
>> >If bootmenu is not started from monitor mode then this "U-Boot
>console"
>> >command just enter into monitor mode. And I think that you can
>already
>> >block monitor mode and therefore has ability of this secure boot
>> >scheme.
>> >
>> >> Best regards
>> >> 
>> >> Heinrich
>> >> 
>> >> >
>> >> >Signed-off-by: Pali Rohár <pali at kernel.org>
>> >> >---
>> >> > cmd/bootmenu.c | 16 +++++++++++++++-
>> >> > 1 file changed, 15 insertions(+), 1 deletion(-)
>> >> >
>> >> >diff --git a/cmd/bootmenu.c b/cmd/bootmenu.c
>> >> >index 1ba7b622e5..9b56bfaa9a 100644
>> >> >--- a/cmd/bootmenu.c
>> >> >+++ b/cmd/bootmenu.c
>> >> >@@ -45,6 +45,7 @@ enum bootmenu_key {
>> >> > 	KEY_UP,
>> >> > 	KEY_DOWN,
>> >> > 	KEY_SELECT,
>> >> >+	KEY_QUIT,
>> >> > };
>> >> > 
>> >> > static char *bootmenu_getoption(unsigned short int n)
>> >> >@@ -109,6 +110,9 @@ static void bootmenu_autoboot_loop(struct
>> >> >bootmenu_data *menu,
>> >> > 			case '\r':
>> >> > 				*key = KEY_SELECT;
>> >> > 				break;
>> >> >+			case 0x3: /* ^C */
>> >> >+				*key = KEY_QUIT;
>> >> >+				break;
>> >> > 			default:
>> >> > 				*key = KEY_NONE;
>> >> > 				break;
>> >> >@@ -187,6 +191,10 @@ static void bootmenu_loop(struct
>bootmenu_data
>> >> >*menu,
>> >> > 	/* enter key was pressed */
>> >> > 	if (c == '\r')
>> >> > 		*key = KEY_SELECT;
>> >> >+
>> >> >+	/* ^C was pressed */
>> >> >+	if (c == 0x3)
>> >> >+		*key = KEY_QUIT;
>> >> > }
>> >> > 
>> >> > static char *bootmenu_choice_entry(void *data)
>> >> >@@ -222,6 +230,12 @@ static char *bootmenu_choice_entry(void
>*data)
>> >> > 			for (i = 0; i < menu->active; ++i)
>> >> > 				iter = iter->next;
>> >> > 			return iter->key;
>> >> >+		case KEY_QUIT:
>> >> >+			/* Quit by choosing the last entry - U-Boot console */
>> >> >+			iter = menu->first;
>> >> >+			while (iter->next)
>> >> >+				iter = iter->next;
>> >> >+			return iter->key;
>> >> > 		default:
>> >> > 			break;
>> >> > 		}
>> >> >@@ -389,7 +403,7 @@ static void menu_display_statusline(struct
>menu
>> >*m)
>> >> > 	printf(ANSI_CURSOR_POSITION, menu->count + 5, 1);
>> >> > 	puts(ANSI_CLEAR_LINE);
>> >> > 	printf(ANSI_CURSOR_POSITION, menu->count + 6, 1);
>> >> >-	puts("  Press UP/DOWN to move, ENTER to select");
>> >> >+	puts("  Press UP/DOWN to move, ENTER to select, CTRL+C to
>quit");
>> >> > 	puts(ANSI_CLEAR_LINE_TO_END);
>> >> > 	printf(ANSI_CURSOR_POSITION, menu->count + 7, 1);
>> >> > 	puts(ANSI_CLEAR_LINE);
>> >> 
>>