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[v4,5/5] kdb: Tweak escape handling for vi users

Message ID 20191025073328.643-6-daniel.thompson@linaro.org
State Accepted
Commit c58ff643763c78bef12874ee39995c9f7f987bc2
Headers show
Series kdb: Cleanup code to read user input and handle escape sequences | expand

Commit Message

Daniel Thompson Oct. 25, 2019, 7:33 a.m. UTC 
Currently if sequences such as "\ehelp\r" are delivered to the console then
the h gets eaten by the escape handling code. Since pressing escape
becomes something of a nervous twitch for vi users (and that escape doesn't
have much effect at a shell prompt) it is more helpful to emit the 'h' than
the '\e'.

We don't simply choose to emit the final character for all escape sequences
since that will do odd things for unsupported escape sequences (in
other words we retain the existing behaviour once we see '\e[').

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>

Reviewed-by: Douglas Anderson <dianders@chromium.org>

---
 kernel/debug/kdb/kdb_io.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
2.21.0
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Patch

diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index f794c0ca4557..8bcdded5d61f 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -163,8 +163,8 @@  char kdb_getchar(void)
 
 		*pbuf++ = key;
 		key = kdb_handle_escape(buf, pbuf - buf);
-		if (key < 0) /* no escape sequence; return first character */
-			return buf[0];
+		if (key < 0) /* no escape sequence; return best character */
+			return buf[pbuf - buf == 2 ? 1 : 0];
 		if (key > 0)
 			return key;
 	}