xserver-multidpi/xfixes/disconnect.c

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xfixes: Add ClientDisconnectMode With Wayland compositors now being able to start Xwayland on demand, the next logical step is to be able to stop Xwayland when there is no more need for it. 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. Worse, the X11 window manager of a Wayland compositor also counts as an X11 client, hence also preventing Xwayland from stopping. Some compositors such as mutter use the XRes extension to query the X11 clients connected, match their PID with the actual executable name and compare those with a list of executables that can be ignored when deciding to kill the Xserver. But that's not just clumsy, it is also racy, because a new X11 client might initiate a connection the X11 server right when the compositor is about to kill it. 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> Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
2021-02-19 12:03:39 +01:00
/*
* Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
* Copyright 2010 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,
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* 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
*
* 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_DIX_CONFIG_H
#include <dix-config.h>
#endif
#include "xfixesint.h"
#include "opaque.h"
static DevPrivateKeyRec ClientDisconnectPrivateKeyRec;
#define ClientDisconnectPrivateKey (&ClientDisconnectPrivateKeyRec)
typedef struct _ClientDisconnect {
int disconnect_mode;
} ClientDisconnectRec, *ClientDisconnectPtr;
#define GetClientDisconnect(s) \
((ClientDisconnectPtr) dixLookupPrivate(&(s)->devPrivates, \
ClientDisconnectPrivateKey))
int
ProcXFixesSetClientDisconnectMode(ClientPtr client)
{
ClientDisconnectPtr pDisconnect = GetClientDisconnect(client);
REQUEST(xXFixesSetClientDisconnectModeReq);
pDisconnect->disconnect_mode = stuff->disconnect_mode;
return Success;
}
int _X_COLD
SProcXFixesSetClientDisconnectMode(ClientPtr client)
{
REQUEST(xXFixesSetClientDisconnectModeReq);
swaps(&stuff->length);
REQUEST_AT_LEAST_SIZE(xXFixesSetClientDisconnectModeReq);
swapl(&stuff->disconnect_mode);
return (*ProcXFixesVector[stuff->xfixesReqType]) (client);
}
int
ProcXFixesGetClientDisconnectMode(ClientPtr client)
{
ClientDisconnectPtr pDisconnect = GetClientDisconnect(client);
xXFixesGetClientDisconnectModeReply reply;
REQUEST_SIZE_MATCH(xXFixesGetClientDisconnectModeReq);
reply = (xXFixesGetClientDisconnectModeReply) {
.type = X_Reply,
.sequenceNumber = client->sequence,
.length = 0,
.disconnect_mode = pDisconnect->disconnect_mode,
};
if (client->swapped) {
swaps(&reply.sequenceNumber);
swapl(&reply.disconnect_mode);
}
WriteToClient(client, sizeof(xXFixesGetClientDisconnectModeReply), &reply);
return Success;
}
int _X_COLD
SProcXFixesGetClientDisconnectMode(ClientPtr client)
{
REQUEST(xXFixesGetClientDisconnectModeReq);
swaps(&stuff->length);
REQUEST_SIZE_MATCH(xXFixesGetClientDisconnectModeReq);
return (*ProcXFixesVector[stuff->xfixesReqType]) (client);
}
Bool
XFixesShouldDisconnectClient(ClientPtr client)
{
ClientDisconnectPtr pDisconnect = GetClientDisconnect(client);
if (!pDisconnect)
return FALSE;
if (dispatchExceptionAtReset & DE_TERMINATE)
return (pDisconnect->disconnect_mode & XFixesClientDisconnectFlagTerminate);
return FALSE;
}
Bool
XFixesClientDisconnectInit(void)
{
if (!dixRegisterPrivateKey(&ClientDisconnectPrivateKeyRec,
PRIVATE_CLIENT, sizeof(ClientDisconnectRec)))
return FALSE;
return TRUE;
}