[Qemu-devel] [PATCH 1/2] char: add qemu_chr_be_is_fe_connected

[Alon Levy <alevy@redhat.com>]

Note that the handler is called chr_is_guest_connected and not
chr_is_fe_connected, consistent with other members of CharDriverState.

Signed-off-by: Alon Levy <alevy@redhat.com>
---
 hw/virtio-console.c |  9 +++++++++
 include/char/char.h | 11 +++++++++++
 qemu-char.c         |  9 +++++++++
 3 files changed, 29 insertions(+)

diff --git a/hw/virtio-console.c b/hw/virtio-console.c
index e2d1c58..643e24e 100644
--- a/hw/virtio-console.c
+++ b/hw/virtio-console.c
@@ -120,6 +120,13 @@ static void chr_event(void *opaque, int event)
     }
 }
 
+static bool chr_is_guest_connected(void *opaque)
+{
+    VirtConsole *vcon = opaque;
+
+    return vcon->port.guest_connected;
+}
+
 static int virtconsole_initfn(VirtIOSerialPort *port)
 {
     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
@@ -133,6 +140,8 @@ static int virtconsole_initfn(VirtIOSerialPort *port)
     if (vcon->chr) {
         qemu_chr_add_handlers(vcon->chr, chr_can_read, chr_read, chr_event,
                               vcon);
+        /* only user of chr_is_guest_connected so leave it as special cased*/
+        vcon->chr->chr_is_guest_connected = chr_is_guest_connected;
     }
 
     return 0;
diff --git a/include/char/char.h b/include/char/char.h
index 0326b2a..b41ddc0 100644
--- a/include/char/char.h
+++ b/include/char/char.h
@@ -52,6 +52,7 @@ typedef struct {
 #define CHR_TIOCM_RTS	0x004
 
 typedef void IOEventHandler(void *opaque, int event);
+typedef bool IOIsGuestConnectedHandler(void *opaque);
 
 struct CharDriverState {
     void (*init)(struct CharDriverState *s);
@@ -64,6 +65,7 @@ struct CharDriverState {
     IOEventHandler *chr_event;
     IOCanReadHandler *chr_can_read;
     IOReadHandler *chr_read;
+    IOIsGuestConnectedHandler *chr_is_guest_connected;
     void *handler_opaque;
     void (*chr_close)(struct CharDriverState *chr);
     void (*chr_accept_input)(struct CharDriverState *chr);
@@ -229,6 +231,15 @@ void qemu_chr_be_write(CharDriverState *s, uint8_t *buf, int len);
  */
 void qemu_chr_be_event(CharDriverState *s, int event);
 
+/**
+ * @qemu_chr_be_is_fe_connected:
+ *
+ * Back end calls this to check if the front end is connected.
+ *
+ * Returns: true if the guest (front end) is connected, false otherwise.
+ */
+bool qemu_chr_be_is_fe_connected(CharDriverState *s);
+
 void qemu_chr_add_handlers(CharDriverState *s,
                            IOCanReadHandler *fd_can_read,
                            IOReadHandler *fd_read,
diff --git a/qemu-char.c b/qemu-char.c
index 4e011df..77a501a 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -120,6 +120,15 @@ void qemu_chr_be_event(CharDriverState *s, int event)
     s->chr_event(s->handler_opaque, event);
 }
 
+bool qemu_chr_be_is_fe_connected(CharDriverState *s)
+{
+    if (s->chr_is_guest_connected) {
+        return s->chr_is_guest_connected(s->handler_opaque);
+    }
+    /* default to always connected */
+    return true;
+}
+
 static gboolean qemu_chr_generic_open_bh(gpointer opaque)
 {
     CharDriverState *s = opaque;
-- 
1.8.1.4