+static int
+send_xscreensaver_command (Display *dpy, Atom command, long argument,
+ Window *window_ret)
+{
+ char *v = 0;
+ Window window = find_screensaver_window (dpy, &v);
+ XWindowAttributes xgwa;
+
+ if (window_ret)
+ *window_ret = window;
+
+ if (!window)
+ return -1;
+
+ /* Select for property change events, so that we can read the response. */
+ XGetWindowAttributes (dpy, window, &xgwa);
+ XSelectInput (dpy, window, xgwa.your_event_mask | PropertyChangeMask);
+
+ if (command == XA_SCREENSAVER_TIME ||
+ command == XA_SCREENSAVER_VERSION)
+ {
+ XClassHint hint;
+ memset (&hint, 0, sizeof(hint));
+ if (!v || !*v)
+ {
+ fprintf (stderr, "%s: version property not set on window 0x%x?\n",
+ progname, (unsigned int) window);
+ return -1;
+ }
+
+ XGetClassHint(dpy, window, &hint);
+ if (!hint.res_class)
+ {
+ fprintf (stderr, "%s: class hints not set on window 0x%x?\n",
+ progname, (unsigned int) window);
+ return -1;
+ }
+
+ fprintf (stdout, "%s %s", hint.res_class, v);
+
+ if (command != XA_SCREENSAVER_TIME)
+ {
+ fprintf (stdout, "\n");
+ }
+ else
+ {
+ Atom type;
+ int format;
+ unsigned long nitems, bytesafter;
+ unsigned char *data = 0;
+ Bool active_p = False;
+
+ if (XGetWindowProperty (dpy, window, XA_VROOT,
+ 0, 0, False, XA_WINDOW,
+ &type, &format, &nitems, &bytesafter,
+ &data)
+ == Success
+ && type != None)
+ active_p = True;
+
+ if (data) free (data);
+ data = 0;
+
+ if (XGetWindowProperty (dpy, window,
+ XA_SCREENSAVER_TIME,
+ 0, 1, False, XA_INTEGER,
+ &type, &format, &nitems, &bytesafter,
+ &data)
+ == Success
+ && type == XA_INTEGER
+ && data)
+ {
+ CARD32 time32 = *((CARD32 *)data);
+ time_t tt = (time_t) time32;
+
+ if (active_p)
+ fprintf (stdout, ": screen blanked since ");
+ else
+ /* suggestions for a better way to phrase this are welcome. */
+ fprintf (stdout, ": screen non-blanked since ");
+ fprintf (stdout, "%s", ctime(&tt));
+ if (data) free (data);
+ }
+ else
+ {
+ if (data) free (data);
+ fprintf (stdout, "\n");
+ fflush (stdout);
+ fprintf (stderr, "%s: no time on window 0x%x (%s %s).\n",
+ progname, (unsigned int) window,
+ hint.res_class, (v ? v : "???"));
+ return -1;
+ }
+ }
+
+ /* No need to read a response for these commands. */
+ return 1;
+ }
+ else
+ {
+ XEvent event;
+ long arg1 = (command == XA_SELECT ? argument : 0L);
+ event.xany.type = ClientMessage;
+ event.xclient.display = dpy;
+ event.xclient.window = window;
+ event.xclient.message_type = XA_SCREENSAVER;
+ event.xclient.format = 32;
+ memset (&event.xclient.data, 0, sizeof(event.xclient.data));
+ event.xclient.data.l[0] = (long) command;
+ event.xclient.data.l[1] = arg1;
+ if (! XSendEvent (dpy, window, False, 0L, &event))
+ {
+ fprintf (stderr, "%s: XSendEvent(dpy, 0x%x ...) failed.\n",
+ progname, (unsigned int) window);
+ return -1;
+ }
+ }
+ XSync (dpy, 0);
+ return 0;
+}
+
+
+static XErrorHandler old_handler = 0;
+static Bool got_badwindow = False;
+static int
+BadWindow_ehandler (Display *dpy, XErrorEvent *error)
+{
+ /* When we notice a window being created, we spawn a timer that waits
+ 30 seconds or so, and then selects events on that window. This error
+ handler is used so that we can cope with the fact that the window
+ may have been destroyed <30 seconds after it was created.
+ */
+ if (error->error_code == BadWindow)
+ {
+ got_badwindow = True;
+ return 0;
+ }
+ else
+ {
+ fprintf (stderr, "%s: ", progname);
+ return (*old_handler) (dpy, error);
+ }
+}
+
+
+static int
+xscreensaver_command_response (Display *dpy, Window window)
+{
+ int fd = ConnectionNumber (dpy);
+ int timeout = 10;
+ int status;
+ fd_set fds;
+ struct timeval tv;
+
+ while (1)
+ {
+ FD_ZERO(&fds);
+ FD_SET(fd, &fds);
+ memset(&tv, 0, sizeof(tv));
+ tv.tv_sec = timeout;
+ status = select (fd+1, &fds, 0, &fds, &tv);
+
+ if (status < 0)
+ {
+ char buf[1024];
+ sprintf (buf, "%s: waiting for reply", progname);
+ perror (buf);
+ return status;
+ }
+ else if (status == 0)
+ {
+ fprintf (stderr, "%s: no response to command.\n", progname);
+ return -1;
+ }
+ else
+ {
+ XEvent event;
+ XNextEvent (dpy, &event);
+ switch (event.xany.type) {
+ case PropertyNotify:
+ if (event.xproperty.state == PropertyNewValue &&
+ event.xproperty.atom == XA_SCREENSAVER_RESPONSE)
+ {
+ Status st2;
+ Atom type;
+ int format;
+ unsigned long nitems, bytesafter;
+ char *msg = 0;
+
+ old_handler = XSetErrorHandler (BadWindow_ehandler);
+ XSync (dpy, False);
+
+ st2 = XGetWindowProperty (dpy, window,
+ XA_SCREENSAVER_RESPONSE,
+ 0, 1024, True,
+ AnyPropertyType,
+ &type, &format, &nitems, &bytesafter,
+ (unsigned char **) &msg);
+
+ if (got_badwindow)
+ {
+ fprintf (stdout,
+ "%s: xscreensaver window has been deleted.\n",
+ progname);
+ return 0;
+ }
+
+ if (st2 == Success && type != None)
+ {
+ if (type != XA_STRING || format != 8)
+ {
+ fprintf (stderr,
+ "%s: unrecognized response property.\n",
+ progname);
+ if (msg) XFree (msg);
+ return -1;
+ }
+ else if (!msg || (msg[0] != '+' && msg[0] != '-'))
+ {
+ fprintf (stderr,
+ "%s: unrecognized response message.\n",
+ progname);
+ if (msg) XFree (msg);
+ return -1;
+ }
+ else
+ {
+ int ret = (msg[0] == '+' ? 0 : -1);
+ fprintf ((ret < 0 ? stderr : stdout),
+ "%s: %s\n",
+ progname,
+ msg+1);
+ XFree (msg);
+ return ret;
+ }
+ }
+ }
+ break;
+
+ default:
+ fprintf (stderr, "%s: got unexpected response event %d.\n",
+ progname, event.xany.type);
+ return -1;
+ break;
+ }
+ }
+ }
+}
+
+
+int
+xscreensaver_command (Display *dpy, Atom command, long argument)
+{
+ Window w = 0;
+ int status = send_xscreensaver_command (dpy, command, argument, &w);
+ if (status == 0)
+ status = xscreensaver_command_response (dpy, w);
+ fflush (stdout);
+ fflush (stderr);
+ return status;
+}
+
+\f
+#ifdef STANDALONE
+static Atom XA_ACTIVATE, XA_DEACTIVATE, XA_CYCLE, XA_NEXT, XA_PREV;
+static Atom XA_EXIT, XA_RESTART, XA_DEMO, XA_PREFS, XA_LOCK;
+
+static char *progname;
+static char *screensaver_version;
+static char *usage = "\n\
+usage: %s -<option>\n\
+\n\
+ This program provides external control of a running xscreensaver process.\n\
+ Version %s, copyright (c) 1991-1998 Jamie Zawinski <jwz@jwz.org>.\n\
+\n\
+ The xscreensaver program is a daemon that runs in the background.\n\
+ You control a running xscreensaver process by sending it messages\n\
+ with this program, xscreensaver-command. See the man pages for\n\
+ details. These are the arguments understood by xscreensaver-command:\n\
+\n\
+ -demo Ask the xscreensaver process to enter interactive demo mode.\n\
+\n\
+ -prefs Ask the xscreensaver process to bring up the preferences\n\
+ panel.\n\
+\n\
+ -activate Turn on the screensaver (blank the screen), as if the user\n\
+ had been idle for long enough.\n\
+\n\
+ -deactivate Turns off the screensaver (un-blank the screen), as if user\n\
+ activity had been detected.\n\
+\n\
+ -cycle If the screensaver is active (the screen is blanked), then\n\
+ stop the current graphics demo and run a new one (chosen\n\
+ randomly.)\n\
+\n\
+ -next Like either -activate or -cycle, depending on which is more\n\
+ appropriate, except that the graphics hack that will be run\n\
+ is the next one in the list, instead of a randomly-chosen\n\
+ one. In other words, repeatedly executing -next will cause\n\
+ the xscreensaver process to invoke each graphics demo\n\
+ sequentially. (Though using the -demo option is probably\n\
+ an easier way to accomplish that.)\n\
+\n\
+ -prev Like -next, but goes in the other direction.\n\
+\n\
+ -select <N> Like -activate, but runs the Nth element in the list of\n\
+ hacks. By knowing what is in the `programs' list, and in\n\
+ what order, you can use this to activate the screensaver\n\
+ with a particular graphics demo. (The first element in the\n\
+ list is numbered 1, not 0.)\n\
+\n\
+ -exit Causes the xscreensaver process to exit gracefully. This is\n\
+ roughly the same as killing the process with `kill', but it\n\
+ is easier, since you don't need to first figure out the pid.\n\
+ (Note that one must *never* kill xscreensaver with -9!)\n\
+\n\
+ -restart Causes the screensaver process to exit and then restart with\n\
+ the same command line arguments as last time. Do this after\n\
+ you've changed your X resource settings, to cause\n\
+ xscreensaver to notice the changes.\n\
+\n\
+ -lock Tells the running xscreensaver process to lock the screen\n\
+ immediately. This is like -activate, but forces locking as\n\
+ well, even if locking is not the default.\n\
+\n\
+ -version Prints the version of xscreensaver that is currently running\n\
+ on the display -- that is, the actual version number of the\n\
+ running xscreensaver background process, rather than the\n\
+ version number of xscreensaver-command.\n\
+\n\
+ -time Prints the time at which the screensaver last activated or\n\
+ deactivated (roughly, how long the user has been idle or\n\
+ non-idle -- but not quite, since it only tells you when the\n\
+ screen became blanked or un-blanked.)\n\
+\n\
+ See the man page for more details.\n\
+ For updates, check http://www.jwz.org/xscreensaver/\n\
+\n";
+