sconsole

commit b6f6965252c97768365e12fe908fa710cd3c2fb7
parent ed15a97ae2d034f3683e3a51802ee31520967e7c
Author: Colin Cross <ccross@android.com>
Date:   Wed, 20 Mar 2013 18:19:45 -0700

Switch the serial port to blocking after opening

The serial port must be opened non-blocking to avoid waiting for
carrier detect during open, but leaving it set to non-blocking
causes later writes to fail with "Resource temporarily unavailable".
Switch the fd back to blocking mode after opening.

Diffstat:
M
sconsole.c
 | 
16
++++++++++++++++

1 file changed, 16 insertions(+), 0 deletions(-)
diff --git a/sconsole.c b/sconsole.c
@@ -103,11 +103,27 @@ int openserial(const char *device, int speed)
 {
 	struct termios tio;
 	int fd;
+	int fl;
+
+	/* open the serial port non-blocking to avoid waiting for cd */
 	fd = open(device, O_RDWR | O_NOCTTY | O_NDELAY);
 
 	if (fd < 0)
 		return -1;
 
+
+	/* then switch the fd to blocking */
+	fl = fcntl(fd, F_GETFL, 0);
+	if (fl < 0) {
+		close(fd);
+		return -1;
+	}
+	fl = fcntl(fd, F_SETFL,  fl & ~O_NDELAY);
+	if (fl < 0) {
+		close(fd);
+		return -1;
+	}
+
 	if (tcgetattr(fd, &tio))
 		memset(&tio, 0, sizeof(tio));