char: drop data written to a disconnected pty

When a serial port writes data to a pty that's disconnected, drop the
data and return the length dropped. This avoids triggering pointless
retries in callers like the 16550A serial_xmit(), and causes
qemu_chr_fe_write() to write all data to the log file, rather than
logging only while a pty client like virsh console happens to be
connected.

Signed-off-by: Ed Swierk <[email protected]>
Message-Id: <1485870329[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

diff --git a/chardev/char-pty.c b/chardev/char-pty.c
index 27eb85f505627e059254552fc234450e0398c886..ecf2c7a5c4290a5a94ee0fa712a9edc02d066552 100644 (file)
--- a/chardev/char-pty.c
+++ b/chardev/char-pty.c
@@ -129,7 +129,7 @@ static int char_pty_chr_write(Chardev *chr, const uint8_t *buf, int len)
         /* guest sends data, check for (re-)connect */
         pty_chr_update_read_handler_locked(chr);
         if (!s->connected) {
-            return 0;
+            return len;
         }
     }
     return io_channel_send(s->ioc, buf, len);