commit e02bc6de30c44fd668dc0d6e1cd1804f2eed3ed3
author Roger Pau Monne <roger.pau@citrix.com> Fri May 23 17:57:49 2014 +0200
committer Paolo Bonzini <pbonzini@redhat.com> Mon Jun 30 15:04:34 2014 +0200
tree 248484486b6a64e6c79a4560bec751d6130ec505
parent 9328cfd2fe4a7ff86a41b2c26ea33974241d7d4e

serial: poll the serial console with G_IO_HUP

On FreeBSD polling a master pty while the other end is not connected
with G_IO_OUT only results in an endless wait. This is different from
the Linux behaviour, that returns immediately. In order to demonstrate
this, I have the following example code:

http://xenbits.xen.org/people/royger/test_poll.c

When executed on Linux:

$ ./test_poll
In callback

On FreeBSD instead, the callback never gets called:

$ ./test_poll

So, in order to workaround this, poll the source with G_IO_HUP (which
makes the code behave the same way on both Linux and FreeBSD).

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Cc: Michael Tokarev <mjt@tls.msk.ru>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: xen-devel@lists.xenproject.org
[Add hw/char/cadence_uart.c too. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/char/cadence_uart.c

diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
index bf0c853..dbbc167 100644
--- a/hw/char/cadence_uart.c
+++ b/hw/char/cadence_uart.c
@@ -306,7 +306,8 @@
     memmove(s->tx_fifo, s->tx_fifo + ret, s->tx_count);
 
     if (s->tx_count) {
-        int r = qemu_chr_fe_add_watch(s->chr, G_IO_OUT, cadence_uart_xmit, s);
+        int r = qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP,
+                                      cadence_uart_xmit, s);
         assert(r);
     }
 

hw/char/serial.c

diff --git a/hw/char/serial.c b/hw/char/serial.c
index d17da16..54180a9 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -246,7 +246,7 @@
         serial_receive1(s, &s->tsr, 1);
     } else if (qemu_chr_fe_write(s->chr, &s->tsr, 1) != 1) {
         if (s->tsr_retry >= 0 && s->tsr_retry < MAX_XMIT_RETRY &&
-            qemu_chr_fe_add_watch(s->chr, G_IO_OUT, serial_xmit, s) > 0) {
+            qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP, serial_xmit, s) > 0) {
             s->tsr_retry++;
             return FALSE;
         }

hw/char/virtio-console.c

diff --git a/hw/char/virtio-console.c b/hw/char/virtio-console.c
index 54eb15f..752ed2c 100644
--- a/hw/char/virtio-console.c
+++ b/hw/char/virtio-console.c
@@ -70,7 +70,8 @@
         if (!k->is_console) {
             virtio_serial_throttle_port(port, true);
             if (!vcon->watch) {
-                vcon->watch = qemu_chr_fe_add_watch(vcon->chr, G_IO_OUT,
+                vcon->watch = qemu_chr_fe_add_watch(vcon->chr,
+                                                    G_IO_OUT|G_IO_HUP,
                                                     chr_write_unblocked, vcon);
             }
         }

hw/usb/redirect.c

diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c
index 4c6187b..44522d9 100644
--- a/hw/usb/redirect.c
+++ b/hw/usb/redirect.c
@@ -290,7 +290,7 @@
     r = qemu_chr_fe_write(dev->cs, data, count);
     if (r < count) {
         if (!dev->watch) {
-            dev->watch = qemu_chr_fe_add_watch(dev->cs, G_IO_OUT,
+            dev->watch = qemu_chr_fe_add_watch(dev->cs, G_IO_OUT|G_IO_HUP,
                                                usbredir_write_unblocked, dev);
         }
         if (r < 0) {

monitor.c

diff --git a/monitor.c b/monitor.c
index 799131b..5bc70a6 100644
--- a/monitor.c
+++ b/monitor.c
@@ -321,7 +321,7 @@
             mon->outbuf = tmp;
         }
         if (mon->out_watch == 0) {
-            mon->out_watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT,
+            mon->out_watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT|G_IO_HUP,
                                                    monitor_unblocked, mon);
         }
     }