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/*********************************************************
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* Copyright (C) 2010 VMware, Inc. All rights reserved.
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published
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* by the Free Software Foundation version 2.1 and no later version.
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the Lesser GNU General Public
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* License for more details.
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*********************************************************/
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* Sets up an X11 lock atom and check it to avoid multiple running instances
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#include "desktopEventsInt.h"
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#define LOCK_ATOM_NAME "vmware-user-lock"
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******************************************************************************
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* InitGroupLeader -- */ /**
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* This routine sets a few properties related to our main window created
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* by {gdk,gtk}_init. Specifically this routine sets the window title,
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* sets the override_redirect X11 property, and reparents it to the root
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* In addition, this routine will return Xlib handles for the following
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* - Main or group leader window
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* - Display's root window
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* As a result of this function:
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* - groupLeader will have a title of VMUSER_TITLE.
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* - groupLeader, if not already directly parented by the root, will be.
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* - dpy will point to our default display (ex: $DISPLAY).
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* - groupLeader will point to the window created by gtk_init().
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* - rootWindow will point to the root window on $DISPLAY.
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* @param[out] groupLeader Group leader window.
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* @param[out] rootWindow Root window.
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* @return TRUE on success, FALSE on failure.
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******************************************************************************
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InitGroupLeader(Window *groupLeader,
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XSetWindowAttributes attr;
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GdkDisplay *gdkDisplay;
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attr.override_redirect = True;
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gdkDisplay = gdk_display_get_default();
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gdkLeader = gdk_display_get_default_group(gdkDisplay);
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myGroupLeader = GDK_WINDOW_XWINDOW(gdkLeader);
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myRootWindow = GDK_ROOT_WINDOW();
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ASSERT(myGroupLeader);
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/* XXX: With g_set_prgname() being called, this can probably go away. */
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XStoreName(GDK_DISPLAY(), myGroupLeader, VMUSER_TITLE);
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* Sanity check: Set the override redirect property on our group leader
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* window (not default), then re-parent it to the root window (default).
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* This makes sure that (a) a window manager can't re-parent our window,
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* and (b) that we remain a top-level window.
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XChangeWindowAttributes(GDK_DISPLAY(), myGroupLeader, CWOverrideRedirect,
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XReparentWindow(GDK_DISPLAY(), myGroupLeader, myRootWindow, 10, 10);
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XSync(GDK_DISPLAY(), FALSE);
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*groupLeader = myGroupLeader;
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*rootWindow = myRootWindow;
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******************************************************************************
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* QueryX11Lock -- */ /**
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* This is just a wrapper around XGetWindowProperty which queries the
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* window described by <dpy,w> for the property described by lockAtom.
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* @param[in] dpy X11 display to query
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* @param[in] w Window to query
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* @param[in] lockAtom Atom used for locking
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* @return TRUE if property defined by parameters exists; FALSE otherwise.
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******************************************************************************
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QueryX11Lock(Display *dpy,
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Atom ptype; // returned property type
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int pfmt; // returned property format
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unsigned long np; // returned # of properties
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unsigned long remaining; // amount of data remaining in property
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unsigned char *data = NULL;
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if (XGetWindowProperty(dpy, w, lockAtom, 0, 1, False, lockAtom,
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&ptype, &pfmt, &np, &remaining, &data) != Success) {
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g_warning("%s: Unable to query window %lx for property %s\n", __func__, w,
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* Xlib is wacky. If the following test is true, then our property
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* didn't exist for the window in question. As a result, `data' is
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* unset, so don't worry about the lack of XFree(data) here.
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* We care only about the existence of the property, not its value.
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******************************************************************************
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* AcquireDisplayLock -- */ /**
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* This function "locks" the display against being "claimed" by another
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* instance of vmware-user. It will succeed if we're the first/only
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* instance of vmware-user, and fail otherwise.
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* NB: This routine must be called -after- gtk_init().
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* Vmware-user enjoys per-display exclusivity using the following algorithm:
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* 1. Grab X server. (I.e., get exclusive access.)
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* 2. Search for top-level X windows meeting the following criteria:
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* a. named "vmware-user"
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* b. has the property "vmware-user-lock" set.
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* 3a. If any such windows described above found, then another vmware-user
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* process is attached to this display, so we consider the display
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* 3b. Else we're the only one. Set the "vmware-user-lock" property on
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* our top-level window.
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* 4. Ungrab the X server.
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* The first time this routine is ever called during the lifetime of an X
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* session, a new X11 Atom, "vmware-user-lock" is created for the lifetime
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* The "vmware-user-lock" property may be set on this process's group leader
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* @return TRUE if "lock" acquired (i.e., we're the first/only vmware-user
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* process); otherwise FALSE.
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******************************************************************************
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AcquireDisplayLock(void)
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Display *defaultDisplay; // Current default X11 display.
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Window rootWindow; // Root window of defaultDisplay; used as root node
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// passed to XQueryTree().
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Window groupLeader; // Our instance's window group leader. This is
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// implicitly created by gtk_init().
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Window *children = NULL; // Array of windows returned by XQueryTree().
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unsigned int nchildren; // Length of children.
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Window dummy1, dummy2; // Throwaway window IDs for XQueryTree().
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Atom lockAtom; // Refers to the "vmware-user-lock" X11 Atom.
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Bool alreadyLocked = FALSE; // Set to TRUE if we discover lock is held.
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defaultDisplay = GDK_DISPLAY();
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* Reset some of our main window's settings & fetch Xlib handles for
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* the GDK group leader and root windows.
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if (InitGroupLeader(&groupLeader, &rootWindow) == FALSE) {
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g_warning("%s: unable to initialize main window.\n", __func__);
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* Look up the lock atom, creating it if it doesn't already exist.
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lockAtom = XInternAtom(defaultDisplay, LOCK_ATOM_NAME, False);
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if (lockAtom == None) {
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g_warning("%s: unable to create X11 atom: " LOCK_ATOM_NAME "\n", __func__);
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* Okay, so at this point the following is done:
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* 1. Our top-level / group leader window is a child of the display's
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* 2. The window manager can't get its hands on said window.
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* 3. We have a handle on the X11 atom which will be used to identify
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* the X11 property used as our lock.
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g_debug("%s: Grabbing X server.\n", __func__);
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* Neither of these can fail, or at least not in the sense that they'd
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* return an error. Instead we'd likely see an X11 I/O error, tearing
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* the connection down.
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* XSync simply blocks until the XGrabServer request is acknowledged
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* by the server. It makes sure that we don't continue issuing requests,
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* such as XQueryTree, until the server grants our "grab".
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XGrabServer(defaultDisplay);
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XSync(defaultDisplay, False);
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* WARNING: At this point, we have grabbed the X server. Consider the
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* UI to be completely frozen. Under -no- circumstances should we return
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* without ungrabbing the server first.
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if (XQueryTree(defaultDisplay, rootWindow, &dummy1, &dummy2, &children,
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g_warning("%s: XQueryTree failed\n", __func__);
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* Iterate over array of top-level windows. Search for those named
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* vmware-user and with the property "vmware-user-lock" set.
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* If any such windows are found, then another process has already
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* claimed this X session.
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for (index = 0; (index < nchildren) && !alreadyLocked; index++) {
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/* Skip unless window is named vmware-user. */
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if ((XFetchName(defaultDisplay, children[index], &name) == 0) ||
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strcmp(name, VMUSER_TITLE)) {
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* Query the window for the "vmware-user-lock" property.
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alreadyLocked = QueryX11Lock(defaultDisplay, children[index], lockAtom);
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* Yay. Lock isn't held, so go ahead and acquire it.
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if (!alreadyLocked) {
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unsigned char dummy[] = "1";
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g_debug("%s: Setting property " LOCK_ATOM_NAME "\n", __func__);
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* NB: Current Xlib always returns one. This may generate a -fatal- IO
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XChangeProperty(defaultDisplay, groupLeader, lockAtom, lockAtom, 8,
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PropModeReplace, dummy, sizeof dummy);
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XUngrabServer(defaultDisplay);
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XSync(defaultDisplay, False);
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******************************************************************************
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* X11Lock_Init -- */ /**
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* Initializes GTK, and sets up a lock atom to make sure only one vmusr
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* instance is running.
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* On error, this function will request that the application's main loop stop
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* @param[in] ctx Application context.
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* @param[in] pdata Registration data.
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* @return TRUE on success, FALSE if another vmusr instance owns the display or
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* not running in the right container (vmusr).
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******************************************************************************
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X11Lock_Init(ToolsAppCtx *ctx,
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ToolsPluginData *pdata)
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char *argv[] = { NULL, NULL };
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if (strcmp(ctx->name, VMTOOLS_USER_SERVICE) != 0) {
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VMTOOLSAPP_ERROR(ctx, EXIT_FAILURE);
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* We depend on the window title when performing (primitive) vmware-user
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* session detection, and unfortunately for us, GTK has a nasty habit of
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* retitling toplevel windows. That said, we can control GTK's default
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* title by setting Glib's application or program name.
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* XXX Consider using g_set_application_name("VMware User Agent") or
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g_set_prgname(VMUSER_TITLE);
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argv[0] = VMUSER_TITLE;
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/* XXX: is calling gtk_init() multiple times safe? */
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gtk_init(&argc, (char ***) &argv);
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if (!AcquireDisplayLock()) {
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g_warning("Another instance of vmware-user already running. Exiting.\n");
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VMTOOLSAPP_ERROR(ctx, EXIT_FAILURE);
added
removed
services/plugins/desktopEvents/x11Lock.c
