[PATCH] console_countdown: ignore errors in getchar()

[Aleksander Morgado]

The getchar() call may return an error reported as a -1, e.g. when the
console detects a RATP message and switches to RATP mode.

In general it probably is a good idea to ignore these errors in the
console countdown operation; and in particular for the RATP usecase,
this also prevents from interfering with the countdown and menu just
when switching one of the consoles to RATP mode.

As a hint, this is what the standard console was printing due to this
issue when the RATP console was activated:

   Hit m for menu or any other key to stop autoboot: [: missing `]'

Signed-off-by: Aleksander Morgado <aleksander at aleksander.es>
---
 common/console_countdown.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/common/console_countdown.c b/common/console_countdown.c
index 03b9b3353..36da1ce57 100644
--- a/common/console_countdown.c
+++ b/common/console_countdown.c
@@ -47,12 +47,14 @@ int console_countdown(int timeout_s, unsigned flags, char *out_key)
 	do {
 		if (tstc()) {
 			key = getchar();
-			if (flags & CONSOLE_COUNTDOWN_ANYKEY)
-				goto out;
-			if (flags & CONSOLE_COUNTDOWN_RETURN && key == '\n')
-				goto out;
-			if (flags & CONSOLE_COUNTDOWN_CTRLC && key == 3)
-				goto out;
+			if (key >= 0) {
+				if (flags & CONSOLE_COUNTDOWN_ANYKEY)
+					goto out;
+				if (flags & CONSOLE_COUNTDOWN_RETURN && key == '\n')
+					goto out;
+				if (flags & CONSOLE_COUNTDOWN_CTRLC && key == 3)
+					goto out;
+			}
 			key = 0;
 		}
 		if ((flags & CONSOLE_COUNTDOWN_EXTERN) &&
-- 
2.14.1