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).

upstream-commit-id: e02bc6de30c44fd668dc0d6e1cd1804f2eed3ed3

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>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
index 1012f1ad6451d79ac012b084623366434f01cb7c..1f3d1620fb31144e30c900350425d245e5034115 100644 (file)
--- a/hw/char/cadence_uart.c
+++ b/hw/char/cadence_uart.c
@@ -306,7 +306,8 @@ static gboolean cadence_uart_xmit(GIOChannel *chan, GIOCondition cond,
     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);
     }
 

diff --git a/hw/char/serial.c b/hw/char/serial.c
index f4d167f9167070672ffd1f21110c830e55fdf316..2a2c9e5daad77ba0115e1c176aa05a0b9a59bdca 100644 (file)
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -246,7 +246,7 @@ static gboolean serial_xmit(GIOChannel *chan, GIOCondition cond, void *opaque)
         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;
         }

diff --git a/hw/char/virtio-console.c b/hw/char/virtio-console.c
index 6c8be0fe26c5314fc0d96b1d235ba27cb9c3afd6..38e290adeb1ecb06e290e4a4abe1b1ffc423072c 100644 (file)
--- a/hw/char/virtio-console.c
+++ b/hw/char/virtio-console.c
@@ -69,7 +69,8 @@ static ssize_t flush_buf(VirtIOSerialPort *port,
         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);
             }
         }

diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c
index 287a505b481ee02d3f52a5ba242a538ece6f8ea4..06e757d13473670750e57d6fa6c865ce44b58270 100644 (file)
--- a/hw/usb/redirect.c
+++ b/hw/usb/redirect.c
@@ -284,7 +284,7 @@ static int usbredir_write(void *priv, uint8_t *data, int count)
     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) {

diff --git a/monitor.c b/monitor.c
index 342e83baea8bedf89ee19e832e7d47f3aebaebc3..0cbc378e4f2667747e3a5af1894baef756a48edf 100644 (file)
--- a/monitor.c
+++ b/monitor.c
@@ -303,7 +303,7 @@ void monitor_flush(Monitor *mon)
             mon->outbuf = tmp;
         }
         if (mon->watch == 0) {
-            mon->watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT,
+            mon->watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT|G_IO_HUP,
                                                monitor_unblocked, mon);
         }
     }