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 a527c79..5e491f3 100644 (file)
--- 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;