[Qemu-devel] [PATCH 1/2] monitor: Reset HMP mon->rs on CHR_EVENT_CLOSED

[Stratos Psomadakis <psomas@grnet.gr>]

Commit cdaa86a54 ("Add G_IO_HUP handler for socket chardev") exposed a
bug in the way the HMP monitor handles its input.  When a client closes
the connection to the monitor, tcp_chr_read() will catch the HUP
'signal' and call tcp_chr_disconnect() to close the server-side
connection too. Due to the fact that monitor reads 1 byte at a time (for
each tcp_chr_read()), the monitor readline state / buffers can be left
in an inconsistent state (i.e. a half-finished command). Thus, without
calling readline_restart() on mon->rs upon CHR_EVENT_CLOSED, future HMP
commands will fail.

Signed-off-by: Stratos Psomadakis <psomas@grnet.gr>
Signed-off-by: Dimitris Aragiorgis <dimara@grnet.gr>
---
 monitor.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/monitor.c b/monitor.c
index 34cee74..7857300 100644
--- a/monitor.c
+++ b/monitor.c
@@ -5252,6 +5252,7 @@ static void monitor_event(void *opaque, int event)
         break;
 
     case CHR_EVENT_CLOSED:
+        readline_restart(mon->rs);
         mon_refcount--;
         monitor_fdsets_cleanup();
         break;
-- 
1.7.10.4