[PATCH 01/11] vt: minor cleanup to vc_translate_unicode()

Nicolas Pitre
2025-04-10T01:19:03Z

From: Nicolas Pitre <npitre@baylibre.com>

Make it clearer when a sequence is bad.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
---
drivers/tty/vt/vt.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index f5642b3038..b5f3c8a818 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -2817,7 +2817,7 @@ static int vc_translate_unicode(struct vc_data *vc, int c, bool *rescan)
if ((c & 0xc0) == 0x80) {
/* Unexpected continuation byte? */
if (!vc->vc_utf_count)
- return 0xfffd;
+ goto bad_sequence;

vc->vc_utf_char = (vc->vc_utf_char << 6) | (c & 0x3f);
vc->vc_npar++;
@@ -2829,17 +2829,17 @@ static int vc_translate_unicode(struct vc_data *vc, int c, bool *rescan)
/* Reject overlong sequences */
if (c <= utf8_length_changes[vc->vc_npar - 1] ||
c > utf8_length_changes[vc->vc_npar])
- return 0xfffd;
+ goto bad_sequence;

return vc_sanitize_unicode(c);
}

/* Single ASCII byte or first byte of a sequence received */
if (vc->vc_utf_count) {
- /* Continuation byte expected */
+ /* A continuation byte was expected */
*rescan = true;
vc->vc_utf_count = 0;
- return 0xfffd;
+ goto bad_sequence;
}

/* Nothing to do if an ASCII byte was received */
@@ -2858,11 +2858,14 @@ static int vc_translate_unicode(struct vc_data *vc, int c, bool *rescan)
vc->vc_utf_count = 3;
vc->vc_utf_char = (c & 0x07);
} else {
- return 0xfffd;
+ goto bad_sequence;
}

need_more_bytes:
return -1;
+
+bad_sequence:
+ return 0xfffd;
}

static int vc_translate(struct vc_data *vc, int *c, bool *rescan)
--
2.49.0