http://packetstorm.tacticalflex.com/UNIX/admin/xscreensaver-3.27.tar.gz

[xscreensaver] / hacks / screenhack.c

diff --git a/hacks/screenhack.c b/hacks/screenhack.c
index 8a882fcd7b4ddd41426d673f79d387822241abc2..c3c8ad4aa713280b5809c91e3253c2a29d0ff540 100644 (file)
--- a/hacks/screenhack.c
+++ b/hacks/screenhack.c
@@ -57,6 +57,14 @@
 #include "version.h"
 #include "vroot.h"
 
+#ifndef isupper
+# define isupper(c)  ((c) >= 'A' && (c) <= 'Z')
+#endif
+#ifndef _tolower
+# define _tolower(c)  ((c) - 'A' + 'a')
+#endif
+
+
 char *progname;
 XrmDatabase db;
 XtAppContext app;
@@ -244,6 +252,11 @@ pick_visual (Screen *screen)
    */
   Visual *v = 0;
   char *string = get_string_resource ("visualID", "VisualID");
+  char *s;
+
+  if (string)
+    for (s = string; *s; s++)
+      if (isupper (*s)) *s = _tolower (*s);
 
   if (!string || !*string ||
       !strcmp (string, "gl") ||
@@ -262,12 +275,75 @@ pick_visual (Screen *screen)
 }
 
 
+/* Notice when the user has requested a different visual or colormap
+   on a pre-existing window (e.g., "-root -visual truecolor" or
+   "-window-id 0x2c00001 -install") and complain, since when drawing
+   on an existing window, we have no choice about these things.
+ */
+static void
+visual_warning (Screen *screen, Window window, Visual *visual, Colormap cmap,
+                Bool window_p)
+{
+  char *visual_string = get_string_resource ("visualID", "VisualID");
+  Visual *desired_visual = pick_visual (screen);
+  char win[100];
+  char why[100];
+
+  if (window == RootWindowOfScreen (screen))
+    strcpy (win, "root window");
+  else
+    sprintf (win, "window 0x%x", (unsigned long) window);
+
+  if (window_p)
+    sprintf (why, "-window-id 0x%x", (unsigned long) window);
+  else
+    strcpy (why, "-root");
+
+  if (visual_string && *visual_string)
+    {
+      char *s;
+      for (s = visual_string; *s; s++)
+        if (isupper (*s)) *s = _tolower (*s);
+
+      if (!strcmp (visual_string, "default") ||
+          !strcmp (visual_string, "default") ||
+          !strcmp (visual_string, "best"))
+        /* don't warn about these, just silently DWIM. */
+        ;
+      else if (visual != desired_visual)
+        {
+          fprintf (stderr, "%s: ignoring `-visual %s' because of `%s'.\n",
+                   progname, visual_string, why);
+          fprintf (stderr, "%s: using %s's visual 0x%x.\n",
+                   progname, win, XVisualIDFromVisual (visual));
+        }
+      free (visual_string);
+    }
+
+  if (visual == DefaultVisualOfScreen (screen) &&
+      has_writable_cells (screen, visual) &&
+      get_boolean_resource ("installColormap", "InstallColormap"))
+    {
+      fprintf (stderr, "%s: ignoring `-install' because of `%s'.\n",
+               progname, why);
+      fprintf (stderr, "%s: using %s's colormap 0x%x.\n",
+               progname, win, (unsigned long) cmap);
+    }
+
+# ifdef USE_GL
+  if (!validate_gl_visual (stderr, screen, win, visual))
+    exit (1);
+# endif /* USE_GL */
+}
+
+
 int
 main (int argc, char **argv)
 {
   Widget toplevel;
   Display *dpy;
   Window window;
+  Screen *screen;
   Visual *visual;
   Colormap cmap;
   Bool root_p;
@@ -297,8 +373,14 @@ main (int argc, char **argv)
                              merged_options_size, &argc, argv,
                              merged_defaults, 0, 0);
   dpy = XtDisplay (toplevel);
+  screen = XtScreen (toplevel);
   db = XtDatabase (dpy);
+
   XtGetApplicationNameAndClass (dpy, &progname, &progclass);
+
+  /* half-assed way of avoiding buffer-overrun attacks. */
+  if (strlen (progname) >= 100) progname[100] = 0;
+
   XSetErrorHandler (screenhack_ehandler);
 
   XA_WM_PROTOCOLS = XInternAtom (dpy, "WM_PROTOCOLS", False);
@@ -374,6 +456,7 @@ main (int argc, char **argv)
       XGetWindowAttributes (dpy, window, &xgwa);
       cmap = xgwa.colormap;
       visual = xgwa.visual;
+      visual_warning (screen, window, visual, cmap, True);
     }
   else if (root_p)
     {
@@ -383,13 +466,18 @@ main (int argc, char **argv)
       XGetWindowAttributes (dpy, window, &xgwa);
       cmap = xgwa.colormap;
       visual = xgwa.visual;
+      visual_warning (screen, window, visual, cmap, False);
     }
   else
     {
       Boolean def_visual_p;
-      Screen *screen = XtScreen (toplevel);
       visual = pick_visual (screen);
 
+# ifdef USE_GL
+      if (!validate_gl_visual (stderr, screen, "window", visual))
+        exit (1);
+# endif /* USE_GL */
+
       if (toplevel->core.width <= 0)
        toplevel->core.width = 600;
       if (toplevel->core.height <= 0)
@@ -417,6 +505,7 @@ main (int argc, char **argv)
                                    XtNcolormap, cmap,
                                    XtNbackground, (Pixel) bg,
                                    XtNborderColor, (Pixel) bd,
+                                   XtNinput, True,  /* for WM_HINTS */
                                    0);
          XtDestroyWidget (toplevel);
          toplevel = new;
@@ -425,7 +514,10 @@ main (int argc, char **argv)
        }
       else
        {
-         XtVaSetValues (toplevel, XtNmappedWhenManaged, False, 0);
+         XtVaSetValues (toplevel,
+                         XtNmappedWhenManaged, False,
+                         XtNinput, True,  /* for WM_HINTS */
+                         0);
          XtRealizeWidget (toplevel);
          window = XtWindow (toplevel);
 
@@ -482,7 +574,13 @@ main (int argc, char **argv)
     XIfEvent (dpy, &event, MapNotify_event_p, (XPointer) window);
 
   XSync (dpy, False);
-  srandom ((int) time ((time_t *) 0));
+
+  /* This is the one and only place that the random-number generator is
+     seeded in any screenhack.  You do not need to seed the RNG again,
+     it is done for you before your code is invoked. */
+# undef ya_rand_init
+  ya_rand_init (0);
+
   screenhack (dpy, window); /* doesn't return */
   return 0;
 }