From a724dff8a3ba6d5e8d3baf79b0041b1b73bd190d Mon Sep 17 00:00:00 2001

From: Francesco Giudici <fgiudici@redhat.com>

Date: Fri, 17 Jan 2020 16:06:13 +0100

Subject: [PATCH] remote-viewer: add handler for SIGINT signal

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When remote-viewer is started from terminal, CTRL-C sends a SIGINT

signal to the program causing immediate termination. On linux clients

usb redirected devices are left without any kernel driver attached,

causing them to appear as no more available to the host.

Add a SIGINT handler to allow a clean exit, in particular to allow

the kernel to attach back the host driver.

The issue is present on linux only.

To perform usb device redirection, virt-viewer leverages spice-gtk

library, which in turn relies on usbredir library, which uses libusb.

In order to take control of the usb device the auto-loaded kernel

driver must be detached. This is achieved (in the very end) with

libusb_detach_kernel_driver(). Then the device interfaces can be claimed

with libusb_claim_interface() and get in control to the application.

During normal application termination, the usb channel is teared down,

performing a reset of the usb device and giving back the control of the

device to the kernel (libusb_attach_kernel_driver()).

If the application quits without doing this, the device interfaces will

end up with no driver attached, making them not usable in the host

system.

Note that enabling libusb_set_auto_detach_kernel_driver() does not solve

the issue, as this is just a convenient API from libusb: libusb will

take care of detaching/attaching the driver to the interfaces of the usb

device each time a call to libusb_release_interface() and

libusb_claim_interface() is performed. An unexpected quit of the

application will skip the libusb_release_interface() call too, leaving

the interfaces without any driver attached.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1713311

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

Signed-off-by: Francesco Giudici <fgiudici@redhat.com>

---

 src/virt-viewer-app.c | 25 +++++++++++++++++++++++++

 1 file changed, 25 insertions(+)

diff --git a/src/virt-viewer-app.c b/src/virt-viewer-app.c

index da8cfa9..343b1af 100644

--- a/src/virt-viewer-app.c

+++ b/src/virt-viewer-app.c

@@ -37,6 +37,10 @@

 #include <glib/gi18n.h>

 #include <errno.h>

+#ifndef G_OS_WIN32

+#include <glib-unix.h>

+#endif

+

 #ifdef HAVE_SYS_SOCKET_H

 #include <sys/socket.h>

 #endif

@@ -1756,6 +1760,23 @@ static gboolean opt_fullscreen = FALSE;

 static gboolean opt_kiosk = FALSE;

 static gboolean opt_kiosk_quit = FALSE;

+#ifndef G_OS_WIN32

+static gboolean

+sigint_cb(gpointer data)

+{

+    VirtViewerApp *self = VIRT_VIEWER_APP(data);

+    VirtViewerAppPrivate *priv = self->priv;

+

+    g_debug("got SIGINT, quitting\n");

+    if (priv->started)

+        virt_viewer_app_quit(self);

+    else

+        exit(EXIT_SUCCESS);

+

+    return G_SOURCE_CONTINUE;

+}

+#endif

+

 static void

 title_maybe_changed(VirtViewerApp *self, GParamSpec* pspec G_GNUC_UNUSED, gpointer user_data G_GNUC_UNUSED)

 {

@@ -1770,6 +1791,10 @@ virt_viewer_app_init(VirtViewerApp *self)

     gtk_window_set_default_icon_name("virt-viewer");

+#ifndef G_OS_WIN32

+    g_unix_signal_add (SIGINT, sigint_cb, self);

+#endif

+

     self->priv->displays = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL, g_object_unref);

     self->priv->config = g_key_file_new();

     self->priv->config_file = g_build_filename(g_get_user_config_dir(),

-- 

2.26.0