xfixes: Add ClientDisconnectMode

The Xserver itself is capable of terminating itself once all X11 clients
are gone, yet in a typical full session, there are a number of X11
clients running continuously (e.g. the Xsettings daemon, IBus, etc.).

Those always-running clients will prevent the Xserver from terminating,
because the actual number of X11 clients will never drop to 0.

To solve this issue directly at the Xserver level, this add new entries
to the XFixes extension to let the X11 clients themselves specify the
disconnect mode they expect.

Typically, those X11 daemon clients would specify the disconnect mode
XFixesClientDisconnectFlagTerminate to let the Xserver know that they
should not be accounted for when checking the remaining clients prior
to terminate.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>

3 files changed, 112 insertions, 1 deletions

diff --git a/include/X11/extensions/Xfixes.h b/include/X11/extensions/Xfixes.h
index 8995d14..b62b95b 100644
--- a/include/X11/extensions/Xfixes.h
+++ b/include/X11/extensions/Xfixes.h
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
- * Copyright 2011 Red Hat, Inc.
+ * Copyright 2011, 2021 Red Hat, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -264,6 +264,16 @@ XFixesDestroyPointerBarrier(Display *dpy, PointerBarrier b);
 
 #endif /* XFIXES_MAJOR >= 5 */
 
+#if XFIXES_MAJOR >= 6
+
+void
+XFixesSetClientDisconnectMode(Display *dpy, int disconnect_mode);
+
+int
+XFixesGetClientDisconnectMode(Display *dpy);
+
+#endif /* XFIXES_MAJOR >= 6 */
+
 _XFUNCPROTOEND
 
 #endif /* _XFIXES_H_ */
diff --git a/src/Disconnect.c b/src/Disconnect.c
new file mode 100644
index 0000000..047cd69
--- /dev/null
+++ b/src/Disconnect.c
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2021 Red Hat, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+/*
+ * Copyright © 2002 Keith Packard, member of The XFree86 Project, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of Keith Packard not be used in
+ * advertising or publicity pertaining to distribution of the software without
+ * specific, written prior permission.  Keith Packard makes no
+ * representations about the suitability of this software for any purpose.  It
+ * is provided "as is" without express or implied warranty.
+ *
+ * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include "Xfixesint.h"
+#include <limits.h>
+
+void
+XFixesSetClientDisconnectMode(Display *dpy, int disconnect_mode)
+{
+    XFixesExtDisplayInfo *info = XFixesFindDisplay(dpy);
+    xXFixesSetClientDisconnectModeReq *req;
+
+    XFixesSimpleCheckExtension(dpy, info);
+    if (info->major_version < 6)
+	return;
+
+    LockDisplay(dpy);
+    GetReq(XFixesSetClientDisconnectMode, req);
+    req->reqType = info->codes->major_opcode;
+    req->xfixesReqType = X_XFixesSetClientDisconnectMode;
+    req->disconnect_mode = disconnect_mode;
+    UnlockDisplay(dpy);
+    SyncHandle();
+}
+
+int
+XFixesGetClientDisconnectMode(Display *dpy)
+{
+    XFixesExtDisplayInfo *info = XFixesFindDisplay(dpy);
+    xXFixesGetClientDisconnectModeReq *req;
+    xXFixesGetClientDisconnectModeReply rep;
+    int disconnect_mode;
+
+    XFixesCheckExtension(dpy, info, 0);
+    if (info->major_version < 6)
+	return XFixesClientDisconnectFlagDefault;
+
+    LockDisplay(dpy);
+    GetReq(XFixesGetClientDisconnectMode, req);
+    req->reqType = info->codes->major_opcode;
+    req->xfixesReqType = X_XFixesGetClientDisconnectMode;
+
+    if (!_XReply(dpy, (xReply *) &rep, 0, xFalse))
+    {
+	UnlockDisplay(dpy);
+	SyncHandle();
+	return XFixesClientDisconnectFlagDefault;
+    }
+
+    disconnect_mode = rep.disconnect_mode;
+    UnlockDisplay(dpy);
+    SyncHandle();
+
+    return disconnect_mode;
+}
diff --git a/src/Makefile.am b/src/Makefile.am
index 4e3f542..7aed410 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -2,6 +2,7 @@ lib_LTLIBRARIES = libXfixes.la
 
 libXfixes_la_SOURCES = 	\
 	Cursor.c	\
+	Disconnect.c	\
 	Region.c	\
 	SaveSet.c	\
 	Selection.c	\