From: Michael Brown <mcb30@ipxe.org>
Date: Mon, 7 Mar 2011 17:40:12 +0000 (+0000)
Subject: [console] Avoid timer wraparound problems in getchar_timeout()
X-Git-Tag: v1.20.1~2266
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2969a8567ffd1e0fd1096199ec32b78beaf779fc;p=thirdparty%2Fipxe.git

[console] Avoid timer wraparound problems in getchar_timeout()

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---

diff --git a/src/core/getkey.c b/src/core/getkey.c
index d93ba1e64..5710f1900 100644
--- a/src/core/getkey.c
+++ b/src/core/getkey.c
@@ -39,9 +39,9 @@ FILE_LICENCE ( GPL2_OR_LATER );
  * @ret character	Character read from console
  */
 int getchar_timeout ( unsigned long timeout ) {
-	unsigned long expiry = ( currticks() + timeout );
+	unsigned long start = currticks();
 
-	while ( currticks() < expiry ) {
+	while ( ( currticks() - start ) < timeout ) {
 		step();
 		if ( iskey() )
 			return getchar();