[Qemu-devel] [PATCH] add close callback for tty-based char device

["David S. Ahern" <daahern@cisco.com>]

Add a tty close callback. Right now if a guest device that is connected
to a tty-based chardev in the host is removed, the tty is not closed.
With this patch it is closed.

Example use case is connecting an emulated USB serial cable in the guest
to tty0 of the host using the monitor command:

usb_add serial::/dev/tty0

and then removing the device with:

usb_del serial::/dev/tty0

Signed-off-by: David Ahern <daahern@cisco.com>

diff --git a/qemu-char.c b/qemu-char.c
index 800ee6c..ecd84ec 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -1173,6 +1173,20 @@ static int tty_serial_ioctl(CharDriverState *chr,
int cmd
     return 0;
 }

+static void qemu_chr_close_tty(CharDriverState *chr)
+{
+    FDCharDriver *s = chr->opaque;
+    int fd = -1;
+
+    if (s)
+        fd = s->fd_in;
+
+    fd_chr_close(chr);
+
+    if (fd >= 0)
+        close(fd);
+}
+
 static CharDriverState *qemu_chr_open_tty(QemuOpts *opts)
 {
     const char *filename = qemu_opt_get(opts, "path");
@@ -1187,6 +1201,7 @@ static CharDriverState *qemu_chr_open_tty(QemuOpts
*opts)
         return NULL;
     }
     chr->chr_ioctl = tty_serial_ioctl;
+    chr->chr_close = qemu_chr_close_tty;
     return chr;
 }
 #else  /* ! __linux__ && ! __sun__ */