From: Pali Rohár <pali@kernel.org>
Date: Fri, 24 Sep 2021 21:07:10 +0000 (+0200)
Subject: tools: kwboot: Disable non-blocking mode
X-Git-Url: http://git.dujemihanovic.xyz/?a=commitdiff_plain;h=911515b339109d4bdf992441d5efdf4a6f885f95;p=u-boot.git

tools: kwboot: Disable non-blocking mode

The kwboot utility does not handle EAGAIN / EBUSY errors, it expects
blocking mode on tty - it uses select() to check if data is available.

Disable non-blocking mode by clearing O_NDELAY flag which was set by
open().

We can't just take O_NDELAY from open(), because it is required there
until the CLOCAL flag is set on the tty.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <marek.behun@nic.cz>
---

diff --git a/tools/kwboot.c b/tools/kwboot.c
index a527c79cf3..5e491f31a4 100644
--- a/tools/kwboot.c
+++ b/tools/kwboot.c
@@ -639,7 +639,7 @@ baud_fail:
 static int
 kwboot_open_tty(const char *path, int baudrate)
 {
-	int rc, fd;
+	int rc, fd, flags;
 	struct termios tio;
 
 	rc = -1;
@@ -661,6 +661,14 @@ kwboot_open_tty(const char *path, int baudrate)
 	if (rc)
 		goto out;
 
+	flags = fcntl(fd, F_GETFL);
+	if (flags < 0)
+		goto out;
+
+	rc = fcntl(fd, F_SETFL, flags & ~O_NDELAY);
+	if (rc)
+		goto out;
+
 	rc = kwboot_tty_change_baudrate(fd, baudrate);
 	if (rc)
 		goto out;