path: root/src/VBox/Additions/x11/VBoxClient/display.cpp

/* $Id: display.cpp $ */
/** @file
 * X11 guest client - display management.
 */

/*
 * Copyright (C) 2006-2023 Oracle and/or its affiliates.
 *
 * This file is part of VirtualBox base platform packages, as
 * available from https://www.virtualbox.org.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, in version 3 of the
 * License.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <https://www.gnu.org/licenses>.
 *
 * SPDX-License-Identifier: GPL-3.0-only
 */

#include "VBoxClient.h"

#include <iprt/errcore.h>
#include <iprt/file.h>
#include <iprt/mem.h>
#include <iprt/string.h>
#include <iprt/asm.h>

#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/extensions/Xrandr.h>

/** @todo this should probably be replaced by something IPRT */
/* For system() and WEXITSTATUS() */
#include <stdlib.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <limits.h>
#include <poll.h>
#include <time.h>
#include <dlfcn.h>

/* TESTING: Dynamic resizing and mouse integration toggling should work
 * correctly with a range of X servers (pre-1.3, 1.3 and later under Linux, 1.3
 * and later under Solaris) with Guest Additions installed.  Switching to a
 * virtual terminal while a user session is in place should disable dynamic
 * resizing and cursor integration, switching back should re-enable them. */

/** State information needed for the service.  The main VBoxClient code provides
 *  the daemon logic needed by all services. */
struct DISPLAYSTATE
{
    /** Are we initialised yet? */
    bool mfInit;
    /** The connection to the server. */
    Display *pDisplay;
    /** The RandR extension base event number. */
    int cRREventBase;
    /** Can we use version 1.2 or later of the RandR protocol here? */
    bool fHaveRandR12;
    /** The command argument to use for the xrandr binary.  Currently only
     * used to support the non-standard location on some Solaris systems -
     * would it make sense to use absolute paths on all systems? */
    const char *pcszXrandr;
    /** Was there a recent mode hint with no following root window resize, and
     *  if so, have we waited for a reasonable time? */
    time_t timeLastModeHint;
    /** Handle to libXrandr. */
    void *pRandLibraryHandle;
    /** Handle to pXRRSelectInput. */
    void (*pXRRSelectInput) (Display *, Window, int);
    /** Handle to pXRRQueryExtension. */
    Bool (*pXRRQueryExtension) (Display *, int *, int *);
};

static struct DISPLAYSTATE g_DisplayState;

static unsigned char *getRootProperty(struct DISPLAYSTATE *pState, const char *pszName,
                                      long cItems, Atom type)
{
    Atom actualType = None;
    int iFormat = 0;
    unsigned long cReturned = 0;
    unsigned long cAfter = 0;
    unsigned char *pData = 0;

    if (XGetWindowProperty(pState->pDisplay, DefaultRootWindow(pState->pDisplay),
                           XInternAtom(pState->pDisplay, pszName, 0), 0, cItems,
                           False /* delete */, type, &actualType, &iFormat,
                           &cReturned, &cAfter, &pData))
        return NULL;
    return pData;
}

static void doResize(struct DISPLAYSTATE *pState)
{
    /** @note The xrandr command can fail if something else accesses RandR at
     *  the same time.  We just ignore failure for now as we do not know what
     *  someone else is doing. */
    if (!pState->fHaveRandR12)
    {
        char szCommand[256];
        unsigned char *pData;

        pData = getRootProperty(pState, "VBOXVIDEO_PREFERRED_MODE", 1, XA_INTEGER);
        if (pData != NULL)
        {
            RTStrPrintf(szCommand, sizeof(szCommand), "%s -s %ux%u",
                        pState->pcszXrandr, ((unsigned long *)pData)[0] >> 16, ((unsigned long *)pData)[0] & 0xFFFF);
            int rcShutUpGcc = system(szCommand); RT_NOREF_PV(rcShutUpGcc);
            XFree(pData);
        }
    }
    else
    {
        const char szCommandBase[] =
            "%s --output VGA-0 --auto --output VGA-1 --auto --right-of VGA-0 "
               "--output VGA-2 --auto --right-of VGA-1 --output VGA-3 --auto --right-of VGA-2 "
               "--output VGA-4 --auto --right-of VGA-3 --output VGA-5 --auto --right-of VGA-4 "
               "--output VGA-6 --auto --right-of VGA-5 --output VGA-7 --auto --right-of VGA-6 "
               "--output VGA-8 --auto --right-of VGA-7 --output VGA-9 --auto --right-of VGA-8 "
               "--output VGA-10 --auto --right-of VGA-9 --output VGA-11 --auto --right-of VGA-10 "
               "--output VGA-12 --auto --right-of VGA-11 --output VGA-13 --auto --right-of VGA-12 "
               "--output VGA-14 --auto --right-of VGA-13 --output VGA-15 --auto --right-of VGA-14 "
               "--output VGA-16 --auto --right-of VGA-15 --output VGA-17 --auto --right-of VGA-16 "
               "--output VGA-18 --auto --right-of VGA-17 --output VGA-19 --auto --right-of VGA-18 "
               "--output VGA-20 --auto --right-of VGA-19 --output VGA-21 --auto --right-of VGA-20 "
               "--output VGA-22 --auto --right-of VGA-21 --output VGA-23 --auto --right-of VGA-22 "
               "--output VGA-24 --auto --right-of VGA-23 --output VGA-25 --auto --right-of VGA-24 "
               "--output VGA-26 --auto --right-of VGA-25 --output VGA-27 --auto --right-of VGA-26 "
               "--output VGA-28 --auto --right-of VGA-27 --output VGA-29 --auto --right-of VGA-28 "
               "--output VGA-30 --auto --right-of VGA-29 --output VGA-31 --auto --right-of VGA-30";
        char szCommand[sizeof(szCommandBase) + 256];
        RTStrPrintf(szCommand, sizeof(szCommand), szCommandBase, pState->pcszXrandr);
        int rcShutUpGcc = system(szCommand); RT_NOREF_PV(rcShutUpGcc);
    }
}

/** Main loop: handle display hot-plug events, property updates (which can
 *  signal VT switches hot-plug in old X servers). */
static void runDisplay(struct DISPLAYSTATE *pState, bool volatile *pfShutdown)
{
    Display *pDisplay = pState->pDisplay;
    long cValue = 1;

    /* One way or another we want the preferred mode at server start-up. */
    doResize(pState);
    XSelectInput(pDisplay, DefaultRootWindow(pDisplay), PropertyChangeMask | StructureNotifyMask);
    if (pState->fHaveRandR12)
        pState->pXRRSelectInput(pDisplay, DefaultRootWindow(pDisplay), RRScreenChangeNotifyMask);
    /* Semantics: when VBOXCLIENT_STARTED is set, pre-1.3 X.Org Server driver
     * assumes that a client capable of handling mode hints will be present for the
     * rest of the X session.  If we crash things will not work as they should.
     * I thought that preferable to implementing complex crash-handling logic.
     */
    XChangeProperty(pState->pDisplay, DefaultRootWindow(pState->pDisplay), XInternAtom(pState->pDisplay, "VBOXCLIENT_STARTED", 0),
                    XA_INTEGER, 32, PropModeReplace, (unsigned char *)&cValue, 1);
    /* Interrupting this cleanly will be more work than making it robust
     * against spontaneous termination, especially as it will never get
     * properly tested, so I will go for the second. */
    while (!ASMAtomicReadBool(pfShutdown))
    {
        XEvent event;
        struct pollfd PollFd;
        int pollTimeOut = -1;
        int cFds;

        /* Do not handle overflow. */
        if (pState->timeLastModeHint > 0 && pState->timeLastModeHint < INT_MAX - 2)
            pollTimeOut = 2 - (time(0) - pState->timeLastModeHint);
        PollFd.fd = ConnectionNumber(pDisplay);
        PollFd.events = POLLIN;  /* Hang-up is always reported. */
        XFlush(pDisplay);
        cFds = poll(&PollFd, 1, pollTimeOut >= 0 ? pollTimeOut * 1000 : -1);
        while (XPending(pDisplay))
        {
            XNextEvent(pDisplay, &event);
            /* This property is deleted when the server regains the virtual
             * terminal.  Force the main thread to call xrandr again, as old X
             * servers could not handle it while switched out. */
            if (   !pState->fHaveRandR12
                && event.type == PropertyNotify
                && event.xproperty.state == PropertyDelete
                && event.xproperty.window == DefaultRootWindow(pDisplay)
                && event.xproperty.atom == XInternAtom(pDisplay, "VBOXVIDEO_NO_VT", False))
                doResize(pState);
            if (   !pState->fHaveRandR12
                && event.type == PropertyNotify
                && event.xproperty.state == PropertyNewValue
                && event.xproperty.window == DefaultRootWindow(pDisplay)
                && event.xproperty.atom == XInternAtom(pDisplay, "VBOXVIDEO_PREFERRED_MODE", False))
                doResize(pState);
            if (   pState->fHaveRandR12
                && event.type == pState->cRREventBase + RRScreenChangeNotify)
                pState->timeLastModeHint = time(0);
            if (   event.type == ConfigureNotify
                && event.xproperty.window == DefaultRootWindow(pDisplay))
                pState->timeLastModeHint = 0;
        }
        if (cFds == 0 && pState->timeLastModeHint > 0)
            doResize(pState);
    }
}

static int initDisplay(struct DISPLAYSTATE *pState)
{
    char szCommand[256];
    int status;

    pState->pRandLibraryHandle = dlopen("libXrandr.so", RTLD_LAZY /*| RTLD_LOCAL */);
    if (!pState->pRandLibraryHandle)
        pState->pRandLibraryHandle = dlopen("libXrandr.so.2", RTLD_LAZY /*| RTLD_LOCAL */);
    if (!pState->pRandLibraryHandle)
        pState->pRandLibraryHandle = dlopen("libXrandr.so.2.2.0", RTLD_LAZY /*| RTLD_LOCAL */);

    if (!RT_VALID_PTR(pState->pRandLibraryHandle))
    {
        VBClLogFatalError("Could not locate libXrandr for dlopen\n");
        return VERR_NOT_FOUND;
    }

    *(void **)(&pState->pXRRSelectInput) = dlsym(pState->pRandLibraryHandle, "XRRSelectInput");
    *(void **)(&pState->pXRRQueryExtension) = dlsym(pState->pRandLibraryHandle, "XRRQueryExtension");

    if (   !RT_VALID_PTR(pState->pXRRSelectInput)
        || !RT_VALID_PTR(pState->pXRRQueryExtension))
    {
        VBClLogFatalError("Could not load required libXrandr symbols\n");
        dlclose(pState->pRandLibraryHandle);
        pState->pRandLibraryHandle = NULL;
        return VERR_NOT_FOUND;
    }

    pState->pDisplay = XOpenDisplay(NULL);
    if (!pState->pDisplay)
        return VERR_NOT_FOUND;
    if (!pState->pXRRQueryExtension(pState->pDisplay, &pState->cRREventBase, &status))
        return VERR_NOT_FOUND;
    pState->fHaveRandR12 = false;
    pState->pcszXrandr = "xrandr";
    if (RTFileExists("/usr/X11/bin/xrandr"))
        pState->pcszXrandr = "/usr/X11/bin/xrandr";
    status = system(pState->pcszXrandr);
    if (WEXITSTATUS(status) != 0)  /* Utility or extension not available. */
        VBClLogFatalError("Failed to execute the xrandr utility\n");
    RTStrPrintf(szCommand, sizeof(szCommand), "%s --q12", pState->pcszXrandr);
    status = system(szCommand);
    if (WEXITSTATUS(status) == 0)
        pState->fHaveRandR12 = true;
    return VINF_SUCCESS;
}

/**
 * @interface_method_impl{VBCLSERVICE,pfnInit}
 */
static DECLCALLBACK(int) init(void)
{
    struct DISPLAYSTATE *pSelf = &g_DisplayState;
    int rc;

    if (pSelf->mfInit)
        return VERR_WRONG_ORDER;
    rc = initDisplay(pSelf);
    if (RT_FAILURE(rc))
        return rc;
    if (RT_SUCCESS(rc))
        pSelf->mfInit = true;
    return rc;
}

/**
 * @interface_method_impl{VBCLSERVICE,pfnWorker}
 */
static DECLCALLBACK(int) run(bool volatile *pfShutdown)
{
    struct DISPLAYSTATE *pSelf = &g_DisplayState;

    if (!pSelf->mfInit)
        return VERR_WRONG_ORDER;

    runDisplay(pSelf, pfShutdown);

    return VINF_SUCCESS;
}

/**
 * @interface_method_impl{VBCLSERVICE,pfnStop}
 */
static DECLCALLBACK(void) stop(void)
{
    /* Nothing to do here. Implement empty callback, so
     * main thread can set pfShutdown=true on process termination. */
}

VBCLSERVICE g_SvcDisplayLegacy =
{
    "dp-legacy-x11",                    /* szName */
    "Legacy display assistant",         /* pszDescription */
    ".vboxclient-display",              /* pszPidFilePathTemplate */
    NULL,                               /* pszUsage */
    NULL,                               /* pszOptions */
    NULL,                               /* pfnOption */
    init,                               /* pfnInit */
    run,                                /* pfnWorker */
    stop,                               /* pfnStop */
    NULL,                               /* pfnTerm */
};