X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?p=xscreensaver;a=blobdiff_plain;f=driver%2Fxscreensaver.c;h=4460c19df6125b9c358df07e4a3a179bb06f98e4;hp=8942df98c5198ad6708bcf5bf577508147e87cfe;hb=551b3de3f619c04c2dd1971ee9b3f02e270c28c9;hpb=ce3185de9d9705e259f2b60dd4b5509007fa17d4

diff --git a/driver/xscreensaver.c b/driver/xscreensaver.c
index 8942df98..4460c19d 100644
--- a/driver/xscreensaver.c
+++ b/driver/xscreensaver.c
@@ -1,4 +1,4 @@
-/* xscreensaver, Copyright (c) 1991-1998 Jamie Zawinski <jwz@jwz.org>
+/* xscreensaver, Copyright (c) 1991-1999 Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -131,6 +131,7 @@
 #include <X11/StringDefs.h>
 #include <X11/Shell.h>
 #include <X11/Xos.h>
+#include <netdb.h>	/* for gethostbyname() */
 #ifdef HAVE_XMU
 # ifndef VMS
 #  include <X11/Xmu/Error.h>
@@ -142,7 +143,7 @@
 #endif /* !HAVE_XMU */
 
 #ifdef HAVE_XIDLE_EXTENSION
-#include <X11/extensions/xidle.h>
+# include <X11/extensions/xidle.h>
 #endif /* HAVE_XIDLE_EXTENSION */
 
 #include "xscreensaver.h"
@@ -150,6 +151,7 @@
 #include "yarandom.h"
 #include "resources.h"
 #include "visual.h"
+#include "usleep.h"
 
 saver_info *global_si_kludge = 0;	/* I hate C so much... */
 
@@ -158,8 +160,9 @@ char *progclass = 0;
 XrmDatabase db = 0;
 
 
+static Atom XA_SCREENSAVER_RESPONSE;
 static Atom XA_ACTIVATE, XA_DEACTIVATE, XA_CYCLE, XA_NEXT, XA_PREV;
-static Atom XA_EXIT, XA_RESTART, XA_LOCK;
+static Atom XA_EXIT, XA_RESTART, XA_LOCK, XA_SELECT;
 Atom XA_DEMO, XA_PREFS;
 
 
@@ -168,27 +171,35 @@ static XrmOptionDescRec options [] = {
   { "-cycle",		   ".cycle",		XrmoptionSepArg, 0 },
   { "-lock-mode",	   ".lock",		XrmoptionNoArg, "on" },
   { "-no-lock-mode",	   ".lock",		XrmoptionNoArg, "off" },
+  { "-no-lock",		   ".lock",		XrmoptionNoArg, "off" },
   { "-lock-timeout",	   ".lockTimeout",	XrmoptionSepArg, 0 },
+  { "-lock-vts",	   ".lockVTs",		XrmoptionNoArg, "on" },
+  { "-no-lock-vts",	   ".lockVTs",		XrmoptionNoArg, "off" },
   { "-visual",		   ".visualID",		XrmoptionSepArg, 0 },
   { "-install",		   ".installColormap",	XrmoptionNoArg, "on" },
   { "-no-install",	   ".installColormap",	XrmoptionNoArg, "off" },
   { "-verbose",		   ".verbose",		XrmoptionNoArg, "on" },
   { "-silent",		   ".verbose",		XrmoptionNoArg, "off" },
   { "-timestamp",	   ".timestamp",	XrmoptionNoArg, "on" },
+  { "-capture-stderr",	   ".captureStderr",	XrmoptionNoArg, "on" },
+  { "-no-capture-stderr",  ".captureStderr",	XrmoptionNoArg, "off" },
   { "-xidle-extension",	   ".xidleExtension",	XrmoptionNoArg, "on" },
   { "-no-xidle-extension", ".xidleExtension",	XrmoptionNoArg, "off" },
   { "-mit-extension",	   ".mitSaverExtension",XrmoptionNoArg, "on" },
   { "-no-mit-extension",   ".mitSaverExtension",XrmoptionNoArg, "off" },
   { "-sgi-extension",	   ".sgiSaverExtension",XrmoptionNoArg, "on" },
   { "-no-sgi-extension",   ".sgiSaverExtension",XrmoptionNoArg, "off" },
+  { "-proc-interrupts",	   ".procInterrupts",	XrmoptionNoArg, "on" },
+  { "-no-proc-interrupts", ".procInterrupts",	XrmoptionNoArg, "off" },
   { "-splash",		   ".splash",		XrmoptionNoArg, "on" },
   { "-no-splash",	   ".splash",		XrmoptionNoArg, "off" },
   { "-nosplash",	   ".splash",		XrmoptionNoArg, "off" },
   { "-idelay",		   ".initialDelay",	XrmoptionSepArg, 0 },
   { "-nice",		   ".nice",		XrmoptionSepArg, 0 },
 
-  /* Actually this one is built in to Xt, but just to be sure... */
-  { "-synchronous",	   ".synchronous",	XrmoptionNoArg, "on" }
+  /* Actually these are built in to Xt, but just to be sure... */
+  { "-synchronous",	   ".synchronous",	XrmoptionNoArg, "on" },
+  { "-xrm",		   NULL,		XrmoptionResArg, NULL }
 };
 
 static char *defaults[] = {
@@ -206,7 +217,7 @@ do_help (saver_info *si)
   fflush (stdout);
   fflush (stderr);
   fprintf (stdout, "\
-xscreensaver %s, copyright (c) 1991-1998 by Jamie Zawinski <jwz@jwz.org>\n\
+xscreensaver %s, copyright (c) 1991-1999 by Jamie Zawinski <jwz@jwz.org>\n\
 The standard Xt command-line options are accepted; other options include:\n\
 \n\
     -timeout <minutes>       When the screensaver should activate.\n\
@@ -222,7 +233,8 @@ The standard Xt command-line options are accepted; other options include:\n\
 See the manual for other options and X resources.\n\
 \n\
 The `xscreensaver' program should be left running in the background.\n\
-Use the `xscreensaver-command' program to manipulate a running xscreensaver.\n\
+Use the `xscreensaver-demo' and `xscreensaver-command' programs to\n\
+manipulate a running xscreensaver.\n\
 \n\
 The `*programs' resource controls which graphics demos will be launched by\n\
 the screensaver.  See `man xscreensaver' or the web page for more details.\n\
@@ -230,7 +242,7 @@ the screensaver.  See `man xscreensaver' or the web page for more details.\n\
 Just getting started?  Try this:\n\
 \n\
         xscreensaver &\n\
-        xscreensaver-command -demo\n\
+        xscreensaver-demo\n\
 \n\
 For updates, check http://www.jwz.org/xscreensaver/\n\
 \n",
@@ -241,265 +253,6 @@ For updates, check http://www.jwz.org/xscreensaver/\n\
 }
 
 
-static char *
-reformat_hack(const char *hack)
-{
-  int i;
-  const char *in = hack;
-  int indent = 13;
-  char *h2 = (char *) malloc(strlen(in) + indent + 2);
-  char *out = h2;
-
-  while (isspace(*in)) in++;		/* skip whitespace */
-  while (*in && !isspace(*in) && *in != ':')
-    *out++ = *in++;			/* snarf first token */
-  while (isspace(*in)) in++;		/* skip whitespace */
-
-  if (*in == ':')
-    *out++ = *in++;			/* copy colon */
-  else
-    {
-      in = hack;
-      out = h2;				/* reset to beginning */
-    }
-
-  *out = 0;
-
-  while (isspace(*in)) in++;		/* skip whitespace */
-  for (i = strlen(h2); i < indent; i++)	/* indent */
-    *out++ = ' ';
-
-  while (*in) *out++ = *in++;		/* copy rest of line */
-  *out = 0;
-
-  return h2;
-}
-
-
-static void
-get_screenhacks (saver_info *si)
-{
-  saver_preferences *p = &si->prefs;
-  int i = 0;
-  int hacks_size = 60;
-  int size;
-  char *d;
-
-  d = get_string_resource ("monoPrograms", "MonoPrograms");
-  if (d && !*d) { free(d); d = 0; }
-  if (!d)
-    d = get_string_resource ("colorPrograms", "ColorPrograms");
-  if (d && !*d) { free(d); d = 0; }
-
-  if (d)
-    {
-      fprintf (stderr,
-       "%s: the `monoPrograms' and `colorPrograms' resources are obsolete;\n\
-	see the manual for details.\n", blurb());
-      free(d);
-    }
-
-  d = get_string_resource ("programs", "Programs");
-
-  size = d ? strlen (d) : 0;
-  p->screenhacks = (char **) malloc (sizeof (char *) * hacks_size);
-  p->screenhacks_count = 0;
-
-  while (i < size)
-    {
-      int end, start = i;
-      if (d[i] == ' ' || d[i] == '\t' || d[i] == '\n' || d[i] == 0)
-	{
-	  i++;
-	  continue;
-	}
-      if (hacks_size <= p->screenhacks_count)
-	p->screenhacks = (char **) realloc (p->screenhacks,
-					    (hacks_size = hacks_size * 2) *
-					    sizeof (char *));
-      p->screenhacks [p->screenhacks_count++] = d + i;
-      while (d[i] != 0 && d[i] != '\n')
-	i++;
-      end = i;
-      while (i > start && (d[i-1] == ' ' || d[i-1] == '\t'))
-	i--;
-      d[i] = 0;
-      i = end + 1;
-    }
-
-  /* shrink all whitespace to one space, for the benefit of the "demo"
-     mode display.  We only do this when we can easily tell that the
-     whitespace is not significant (no shell metachars).
-   */
-  for (i = 0; i < p->screenhacks_count; i++)
-    {
-      char *s = p->screenhacks [i];
-      char *s2;
-      int L = strlen (s);
-      int j, k;
-      for (j = 0; j < L; j++)
-	{
-	  switch (s[j])
-	    {
-	    case '\'': case '"': case '`': case '\\':
-	      goto DONE;
-	    case '\t':
-	      s[j] = ' ';
-	    case ' ':
-	      k = 0;
-	      for (s2 = s+j+1; *s2 == ' ' || *s2 == '\t'; s2++)
-		k++;
-	      if (k > 0)
-		{
-		  for (s2 = s+j+1; s2[k]; s2++)
-		    *s2 = s2[k];
-		  *s2 = 0;
-		}
-	      break;
-	    }
-	}
-    DONE:
-      p->screenhacks[i] = reformat_hack(s);  /* mallocs */
-    }
-
-  if (p->screenhacks_count)
-    {
-      /* Shrink down the screenhacks array to be only as big as it needs to.
-	 This doesn't really matter at all. */
-      p->screenhacks = (char **)
-	realloc (p->screenhacks, ((p->screenhacks_count + 1) *
-				  sizeof(char *)));
-      p->screenhacks [p->screenhacks_count] = 0;
-    }
-  else
-    {
-      free (p->screenhacks);
-      p->screenhacks = 0;
-    }
-}
-
-
-static Bool blurb_timestamp_p = False;   /* kludge */
-
-
-static void
-get_resources (saver_info *si)
-{
-  char *s;
-  saver_preferences *p = &si->prefs;
-
-  p->xsync_p	    = get_boolean_resource ("synchronous", "Synchronous");
-  if (p->xsync_p)
-    XSynchronize(si->dpy, True);
-
-  p->verbose_p	    = get_boolean_resource ("verbose", "Boolean");
-  p->timestamp_p    = get_boolean_resource ("timestamp", "Boolean");
-  p->lock_p	    = get_boolean_resource ("lock", "Boolean");
-  p->fade_p	    = get_boolean_resource ("fade", "Boolean");
-  p->unfade_p	    = get_boolean_resource ("unfade", "Boolean");
-  p->fade_seconds   = get_seconds_resource ("fadeSeconds", "Time");
-  p->fade_ticks	    = get_integer_resource ("fadeTicks", "Integer");
-  p->install_cmap_p = get_boolean_resource ("installColormap", "Boolean");
-  p->nice_inferior  = get_integer_resource ("nice", "Nice");
-
-  p->initial_delay   = get_seconds_resource ("initialDelay", "Time");
-  p->splash_duration = 1000 * get_seconds_resource ("splashDuration", "Time");
-  p->timeout         = 1000 * get_minutes_resource ("timeout", "Time");
-  p->lock_timeout    = 1000 * get_minutes_resource ("lockTimeout", "Time");
-  p->cycle           = 1000 * get_minutes_resource ("cycle", "Time");
-
-#ifndef NO_LOCKING
-  p->passwd_timeout = 1000 * get_seconds_resource ("passwdTimeout", "Time");
-#endif
-
-  p->pointer_timeout = 1000 * get_seconds_resource ("pointerPollTime", "Time");
-  p->notice_events_timeout = 1000*get_seconds_resource("windowCreationTimeout",
-						       "Time");
-  p->shell = get_string_resource ("bourneShell", "BourneShell");
-
-  p->help_url = get_string_resource("helpURL", "URL");
-  p->load_url_command = get_string_resource("loadURL", "LoadURL");
-
-  if ((s = get_string_resource ("splash", "Boolean")))
-    if (!get_boolean_resource("splash", "Boolean"))
-      p->splash_duration = 0;
-  if (s) free (s);
-
-  /* don't set use_xidle_extension unless it is explicitly specified */
-  if ((s = get_string_resource ("xidleExtension", "Boolean")))
-    p->use_xidle_extension = get_boolean_resource ("xidleExtension","Boolean");
-  else
-#ifdef HAVE_XIDLE_EXTENSION		/* pick a default */
-    p->use_xidle_extension = True;	/* if we have it, use it */
-#else  /* !HAVE_XIDLE_EXTENSION */
-    p->use_xidle_extension = False;
-#endif /* !HAVE_XIDLE_EXTENSION */
-  if (s) free (s);
-
-  /* don't set use_mit_extension unless it is explicitly specified */
-  if ((s = get_string_resource ("mitSaverExtension", "Boolean")))
-    p->use_mit_saver_extension = get_boolean_resource ("mitSaverExtension",
-						       "Boolean");
-  else
-#ifdef HAVE_MIT_SAVER_EXTENSION		/* pick a default */
-    p->use_mit_saver_extension = False;	/* Default false, because it sucks */
-#else  /* !HAVE_MIT_SAVER_EXTENSION */
-    p->use_mit_saver_extension = False;
-#endif /* !HAVE_MIT_SAVER_EXTENSION */
-  if (s) free (s);
-
-
-  /* don't set use_mit_extension unless it is explicitly specified */
-  if ((s = get_string_resource ("sgiSaverExtension", "Boolean")))
-    p->use_sgi_saver_extension = get_boolean_resource ("sgiSaverExtension",
-						       "Boolean");
-  else
-#ifdef HAVE_SGI_SAVER_EXTENSION		/* pick a default */
-    p->use_sgi_saver_extension = True;	/* if we have it, use it */
-#else  /* !HAVE_SGI_SAVER_EXTENSION */
-    p->use_sgi_saver_extension = False;
-#endif /* !HAVE_SGI_SAVER_EXTENSION */
-  if (s) free (s);
-
-
-  /* Throttle the various timeouts to reasonable values.
-   */
-#ifndef NO_LOCKING
-  if (p->passwd_timeout == 0) p->passwd_timeout = 30000;	 /* 30 secs */
-#endif
-  if (p->timeout < 10000) p->timeout = 10000;			 /* 10 secs */
-  if (p->cycle != 0 && p->cycle < 2000) p->cycle = 2000;	 /*  2 secs */
-  if (p->pointer_timeout == 0) p->pointer_timeout = 5000;	 /*  5 secs */
-  if (p->notice_events_timeout == 0)
-    p->notice_events_timeout = 10000;				 /* 10 secs */
-  if (p->fade_seconds == 0 || p->fade_ticks == 0)
-    p->fade_p = False;
-  if (! p->fade_p) p->unfade_p = False;
-
-  p->watchdog_timeout = p->cycle;
-  if (p->watchdog_timeout < 30000) p->watchdog_timeout = 30000;	  /* 30 secs */
-  if (p->watchdog_timeout > 3600000) p->watchdog_timeout = 3600000; /*  1 hr */
-
-#ifdef NO_LOCKING
-  si->locking_disabled_p = True;
-  si->nolock_reason = "not compiled with locking support";
-#endif /* NO_LOCKING */
-
-  get_screenhacks (si);
-
-  if (p->debug_p)
-    {
-      XSynchronize(si->dpy, True);
-      p->xsync_p = True;
-      p->verbose_p = True;
-      p->timestamp_p = True;
-      p->initial_delay = 0;
-    }
-
-  blurb_timestamp_p = p->timestamp_p;
-}
-
-
 char *
 timestring (void)
 {
@@ -510,20 +263,26 @@ timestring (void)
   return str;
 }
 
-static void initialize (saver_info *si, int argc, char **argv);
-static void main_loop (saver_info *si);
+static Bool blurb_timestamp_p = False;   /* kludge */
 
-int
-main (int argc, char **argv)
+const char *
+blurb (void)
 {
-  saver_info si;
-  memset(&si, 0, sizeof(si));
-  global_si_kludge = &si;	/* I hate C so much... */
-  initialize (&si, argc, argv);
-  if (!si.demo_mode_p)
-    pop_splash_dialog (&si);
-  main_loop (&si);		/* doesn't return */
-  return 0;
+  if (!blurb_timestamp_p)
+    return progname;
+  else
+    {
+      static char buf[255];
+      char *ct = timestring();
+      int n = strlen(progname);
+      if (n > 100) n = 99;
+      strncpy(buf, progname, n);
+      buf[n++] = ':';
+      buf[n++] = ' ';
+      strncpy(buf+n, ct+11, 8);
+      strcpy(buf+n+9, ": ");
+      return buf;
+    }
 }
 
 
@@ -532,6 +291,8 @@ saver_ehandler (Display *dpy, XErrorEvent *error)
 {
   saver_info *si = global_si_kludge;	/* I hate C so much... */
 
+  if (!real_stderr) real_stderr = stderr;
+
   fprintf (real_stderr, "\n"
 	   "#######################################"
 	   "#######################################\n\n"
@@ -548,9 +309,25 @@ saver_ehandler (Display *dpy, XErrorEvent *error)
 	}
       else
 	{
-	  fprintf(real_stderr,
-		  "%s: to dump a core file, re-run with `-sync'.\n\n",
-		  blurb());
+          fprintf (real_stderr,
+                   "#######################################"
+                   "#######################################\n\n");
+          fprintf (real_stderr,
+   "    If at all possible, please re-run xscreensaver with the command line\n"
+   "    arguments `-sync -verbose', and reproduce this bug.  That will cause\n"
+   "    xscreensaver to dump a `core' file to the current directory.  Please\n"
+   "    include the stack trace from that core file in your bug report.\n"
+   "\n"
+   "    http://www.jwz.org/xscreensaver/bugs.html explains how to create the\n"
+   "    most useful bug reports, and how to examine core files.\n"
+   "\n"
+   "    The more information you can provide, the better.  But please report\n"
+   "    report this bug, regardless!\n"
+   "\n");
+          fprintf (real_stderr,
+                   "#######################################"
+                   "#######################################\n\n");
+
 	  saver_exit (si, -1, 0);
 	}
     }
@@ -560,32 +337,67 @@ saver_ehandler (Display *dpy, XErrorEvent *error)
 }
 
 
-const char *
-blurb (void)
+/* This error handler is used only while the X connection is being set up;
+   after we've got a connection, we don't use this handler again.  The only
+   reason for having this is so that we can present a more idiot-proof error
+   message than "cannot open display."
+ */
+static void 
+startup_ehandler (String name, String type, String class,
+                  String defalt,  /* one can't even spel properly
+                                     in this joke of a language */
+                  String *av, Cardinal *ac)
 {
-  if (!blurb_timestamp_p)
-    return progname;
-  else
-    {
-      static char buf[255];
-      char *ct = timestring();
-      int n = strlen(progname);
-      if (n > 100) n = 99;
-      strncpy(buf, progname, n);
-      buf[n++] = ':';
-      buf[n++] = ' ';
-      strncpy(buf+n, ct+11, 8);
-      strcpy(buf+n+9, ": ");
-      return buf;
-    }
+  char fmt[512];
+  String p[10];
+  saver_info *si = global_si_kludge;	/* I hate C so much... */
+  XrmDatabase *db = XtAppGetErrorDatabase(si->app);
+  *fmt = 0;
+  XtAppGetErrorDatabaseText(si->app, name, type, class, defalt,
+                            fmt, sizeof(fmt)-1, *db);
+
+  fprintf (stderr, "%s: ", blurb());
+
+  memset (p, 0, sizeof(p));
+  if (*ac > countof (p)) *ac = countof (p);
+  memcpy ((char *) p, (char *) av, (*ac) * sizeof(*av));
+  fprintf (stderr, fmt,		/* Did I mention that I hate C? */
+           p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], p[8], p[9]);
+  fprintf (stderr, "\n");
+
+  describe_uids (si, stderr);
+  fprintf (stderr, "\n"
+           "%s: Errors at startup are usually authorization problems.\n"
+           "              Did you read the manual?  Specifically, the parts\n"
+           "              that talk about XAUTH, XDM, and root logins?\n"
+           "\n"
+           "              http://www.jwz.org/xscreensaver/man.html\n"
+           "\n",
+           blurb());
+
+  fflush (stderr);
+  fflush (stdout);
+  exit (1);
 }
 
+
+/* The zillions of initializations.
+ */
+
+/* Set progname, version, etc.  This is done very early.
+ */
 static void
-initialize_connection (saver_info *si, int argc, char **argv)
+set_version_string (saver_info *si, int *argc, char **argv)
 {
-  int i;
-  Widget toplevel_shell;
-  saver_preferences *p = &si->prefs;
+  progclass = "XScreenSaver";
+
+  /* progname is reset later, after we connect to X. */
+  progname = strrchr(argv[0], '/');
+  if (progname) progname++;
+  else progname = argv[0];
+
+  if (strlen(progname) > 100)	/* keep it short. */
+    progname[99] = 0;
 
   /* The X resource database blows up if argv[0] has a "." in it. */
   {
@@ -594,68 +406,227 @@ initialize_connection (saver_info *si, int argc, char **argv)
       *s = '_';
   }
 
+  si->version = (char *) malloc (5);
+  memcpy (si->version, screensaver_id + 17, 4);
+  si->version [4] = 0;
+}
+
+
+/* Initializations that potentially take place as a priveleged user:
+   If the xscreensaver executable is setuid root, then these initializations
+   are run as root, before discarding privileges.
+ */
+static void
+privileged_initialization (saver_info *si, int *argc, char **argv)
+{
+#ifndef NO_LOCKING
+  /* before hack_uid() for proper permissions */
+  lock_priv_init (*argc, argv, si->prefs.verbose_p);
+#endif /* NO_LOCKING */
+
+#ifndef NO_SETUID
+  hack_uid (si);
+#endif /* NO_SETUID */
+}
+
+
+/* Figure out what locking mechanisms are supported.
+ */
+static void
+lock_initialization (saver_info *si, int *argc, char **argv)
+{
+#ifdef NO_LOCKING
+  si->locking_disabled_p = True;
+  si->nolock_reason = "not compiled with locking support";
+#else /* !NO_LOCKING */
+  si->locking_disabled_p = False;
+
+  /* Finish initializing locking, now that we're out of privileged code. */
+  if (! lock_init (*argc, argv, si->prefs.verbose_p))
+    {
+      si->locking_disabled_p = True;
+      si->nolock_reason = "error getting password";
+    }
+#endif /* NO_LOCKING */
+
+#ifndef NO_SETUID
+  hack_uid (si);
+#endif /* NO_SETUID */
+}
+
+
+/* Open the connection to the X server, and intern our Atoms.
+ */
+static Widget
+connect_to_server (saver_info *si, int *argc, char **argv)
+{
+  Widget toplevel_shell;
+
+  XSetErrorHandler (saver_ehandler);
+
+  XtAppSetErrorMsgHandler (si->app, startup_ehandler);
   toplevel_shell = XtAppInitialize (&si->app, progclass,
 				    options, XtNumber (options),
-				    &argc, argv, defaults, 0, 0);
+				    argc, argv, defaults, 0, 0);
+  XtAppSetErrorMsgHandler (si->app, 0);
 
   si->dpy = XtDisplay (toplevel_shell);
-  si->db = XtDatabase (si->dpy);
+  si->prefs.db = XtDatabase (si->dpy);
   XtGetApplicationNameAndClass (si->dpy, &progname, &progclass);
 
-  if(strlen(progname)  > 100) progname [99] = 0;  /* keep it short. */
+  if(strlen(progname) > 100)	/* keep it short. */
+    progname [99] = 0;
+
+  db = si->prefs.db;	/* resources.c needs this */
 
-  db = si->db;	/* resources.c needs this */
+  XA_VROOT = XInternAtom (si->dpy, "__SWM_VROOT", False);
+  XA_SCREENSAVER = XInternAtom (si->dpy, "SCREENSAVER", False);
+  XA_SCREENSAVER_VERSION = XInternAtom (si->dpy, "_SCREENSAVER_VERSION",False);
+  XA_SCREENSAVER_ID = XInternAtom (si->dpy, "_SCREENSAVER_ID", False);
+  XA_SCREENSAVER_TIME = XInternAtom (si->dpy, "_SCREENSAVER_TIME", False);
+  XA_SCREENSAVER_RESPONSE = XInternAtom (si->dpy, "_SCREENSAVER_RESPONSE",
+					 False);
+  XA_XSETROOT_ID = XInternAtom (si->dpy, "_XSETROOT_ID", False);
+  XA_ACTIVATE = XInternAtom (si->dpy, "ACTIVATE", False);
+  XA_DEACTIVATE = XInternAtom (si->dpy, "DEACTIVATE", False);
+  XA_RESTART = XInternAtom (si->dpy, "RESTART", False);
+  XA_CYCLE = XInternAtom (si->dpy, "CYCLE", False);
+  XA_NEXT = XInternAtom (si->dpy, "NEXT", False);
+  XA_PREV = XInternAtom (si->dpy, "PREV", False);
+  XA_SELECT = XInternAtom (si->dpy, "SELECT", False);
+  XA_EXIT = XInternAtom (si->dpy, "EXIT", False);
+  XA_DEMO = XInternAtom (si->dpy, "DEMO", False);
+  XA_PREFS = XInternAtom (si->dpy, "PREFS", False);
+  XA_LOCK = XInternAtom (si->dpy, "LOCK", False);
 
-  if (argc == 2 &&
-      (!strcmp (argv[1], "-h") ||
-       !strcmp (argv[1], "-help") ||
-       !strcmp (argv[1], "--help")))
-    do_help (si);
+  return toplevel_shell;
+}
 
-  else if (argc == 2 && !strcmp (argv[1], "-debug"))
-    si->prefs.debug_p = True;  /* no resource for this one, out of paranoia. */
 
-  else if (argc > 1)
+/* Handle the command-line arguments that were not handled for us by Xt.
+   Issue an error message and exit if there are unknown options.
+ */
+static void
+process_command_line (saver_info *si, int *argc, char **argv)
+{
+  int i;
+  for (i = 1; i < *argc; i++)
     {
-      const char *s = argv[1];
-      fprintf (stderr, "%s: unknown option \"%s\".  Try \"-help\".\n",
-	       blurb(), s);
-
-      if (s[0] == '-' && s[1] == '-') s++;
-      if (!strcmp (s, "-activate") ||
-	  !strcmp (s, "-deactivate") ||
-	  !strcmp (s, "-cycle") ||
-	  !strcmp (s, "-next") ||
-	  !strcmp (s, "-prev") ||
-	  !strcmp (s, "-exit") ||
-	  !strcmp (s, "-restart") ||
-	  !strcmp (s, "-demo") ||
-	  !strcmp (s, "-prefs") ||
-	  !strcmp (s, "-preferences") ||
-	  !strcmp (s, "-lock") ||
-	  !strcmp (s, "-version") ||
-	  !strcmp (s, "-time"))
+      if (!strcmp (argv[i], "-debug"))
+	/* no resource for this one, out of paranoia. */
+	si->prefs.debug_p = True;
+
+      else if (!strcmp (argv[i], "-h") ||
+	       !strcmp (argv[i], "-help") ||
+	       !strcmp (argv[i], "--help"))
+	do_help (si);
+
+      else
 	{
-	  fprintf (stderr, "\n\
-    However, %s is an option to the `xscreensaver-command' program.\n\
+	  const char *s = argv[i];
+	  fprintf (stderr, "%s: unknown option \"%s\".  Try \"-help\".\n",
+		   blurb(), s);
+
+	  if (s[0] == '-' && s[1] == '-') s++;
+	  if (!strcmp (s, "-activate") ||
+	      !strcmp (s, "-deactivate") ||
+	      !strcmp (s, "-cycle") ||
+	      !strcmp (s, "-next") ||
+	      !strcmp (s, "-prev") ||
+	      !strcmp (s, "-exit") ||
+	      !strcmp (s, "-restart") ||
+	      !strcmp (s, "-demo") ||
+	      !strcmp (s, "-prefs") ||
+	      !strcmp (s, "-preferences") ||
+	      !strcmp (s, "-lock") ||
+	      !strcmp (s, "-version") ||
+	      !strcmp (s, "-time"))
+	    {
+
+	      if (!strcmp (s, "-demo") || !strcmp (s, "-prefs"))
+		fprintf (stderr, "\n\
+    Perhaps you meant to run the `xscreensaver-demo' program instead?\n");
+	      else
+		fprintf (stderr, "\n\
+    However, `%s' is an option to the `xscreensaver-command' program.\n", s);
+
+	      fprintf (stderr, "\
     The `xscreensaver' program is a daemon that runs in the background.\n\
     You control a running xscreensaver process by sending it messages\n\
-    with `xscreensaver-command'.  See the man pages for details,\n\
-    or check the web page: http://www.jwz.org/xscreensaver/\n\n",
-		   s);
-
-	  /* Since version 1.21 renamed the "-lock" option to "-lock-mode",
-	     suggest that explicitly. */
-	  if (!strcmp (s, "-lock"))
-	    fprintf (stderr, "\
+    with `xscreensaver-demo' or `xscreensaver-command'.\n\
+.   See the man pages for details, or check the web page:\n\
+    http://www.jwz.org/xscreensaver/\n\n");
+
+	      /* Since version 1.21 renamed the "-lock" option to "-lock-mode",
+		 suggest that explicitly. */
+	      if (!strcmp (s, "-lock"))
+		fprintf (stderr, "\
     Or perhaps you meant either the \"-lock-mode\" or the\n\
     \"-lock-timeout <minutes>\" options to xscreensaver?\n\n");
+	    }
+
+	  exit (1);
 	}
+    }
+}
 
-      exit (1);
+
+/* Print out the xscreensaver banner to the tty if applicable;
+   Issue any other warnings that are called for at this point.
+ */
+static void
+print_banner (saver_info *si)
+{
+  saver_preferences *p = &si->prefs;
+
+  /* This resource gets set some time before the others, so that we know
+     whether to print the banner (and so that the banner gets printed before
+     any resource-database-related error messages.)
+   */
+  p->verbose_p = (p->debug_p || get_boolean_resource ("verbose", "Boolean"));
+
+  /* Ditto, for the locking_disabled_p message. */
+  p->lock_p = get_boolean_resource ("lock", "Boolean");
+
+  if (p->verbose_p)
+    fprintf (stderr,
+	     "%s %s, copyright (c) 1991-1999 "
+	     "by Jamie Zawinski <jwz@jwz.org>.\n",
+	     progname, si->version);
+
+  if (p->debug_p)
+    fprintf (stderr, "\n"
+	     "%s: Warning: running in DEBUG MODE.  Be afraid.\n"
+	     "\n"
+	     "\tNote that in debug mode, the xscreensaver window will only\n"
+	     "\tcover the left half of the screen.  (The idea is that you\n"
+	     "\tcan still see debugging output in a shell, if you position\n"
+	     "\tit on the right side of the screen.)\n"
+	     "\n"
+	     "\tDebug mode is NOT SECURE.  Do not run with -debug in\n"
+	     "\tuntrusted environments.\n"
+	     "\n",
+	     blurb());
+
+  if (p->verbose_p)
+    {
+      if (!si->uid_message || !*si->uid_message)
+	describe_uids (si, stderr);
+      else
+	{
+	  if (si->orig_uid && *si->orig_uid)
+	    fprintf (stderr, "%s: initial effective uid/gid was %s.\n",
+		     blurb(), si->orig_uid);
+	  fprintf (stderr, "%s: %s\n", blurb(), si->uid_message);
+	}
+
+      fprintf (stderr, "%s: in process %lu.\n", blurb(),
+	       (unsigned long) getpid());
     }
-  get_resources (si);
 
+  /* If locking was not able to be initalized for some reason, explain why.
+     (This has to be done after we've read the lock_p resource.)
+   */
   if (p->lock_p && si->locking_disabled_p)
     {
       p->lock_p = False;
@@ -664,390 +635,458 @@ initialize_connection (saver_info *si, int argc, char **argv)
       if (strstr (si->nolock_reason, "passw"))
 	fprintf (stderr, "%s: does xscreensaver need to be setuid?  "
 		 "consult the manual.\n", blurb());
+      else if (strstr (si->nolock_reason, "running as "))
+	fprintf (stderr, 
+		 "%s: locking only works when xscreensaver is launched\n"
+		 "\t by a normal, non-privileged user (e.g., not \"root\".)\n"
+		 "\t See the manual for details.\n",
+		 blurb());
     }
+}
 
-  /* Defer the printing of this message until after we have loaded the
-     resources and know whether `verbose' is on.
-   */
-  if (p->verbose_p && si->uid_message)
-    {
-      if (si->orig_uid && *si->orig_uid)
-	fprintf (stderr, "%s: initial effective uid/gid was %s.\n", blurb(),
-		 si->orig_uid);
-      fprintf (stderr, "%s: %s\n", blurb(), si->uid_message);
-    }
 
-  XA_VROOT = XInternAtom (si->dpy, "__SWM_VROOT", False);
-  XA_SCREENSAVER = XInternAtom (si->dpy, "SCREENSAVER", False);
-  XA_SCREENSAVER_VERSION = XInternAtom (si->dpy, "_SCREENSAVER_VERSION",False);
-  XA_SCREENSAVER_ID = XInternAtom (si->dpy, "_SCREENSAVER_ID", False);
-  XA_SCREENSAVER_TIME = XInternAtom (si->dpy, "_SCREENSAVER_TIME", False);
-  XA_XSETROOT_ID = XInternAtom (si->dpy, "_XSETROOT_ID", False);
-  XA_ACTIVATE = XInternAtom (si->dpy, "ACTIVATE", False);
-  XA_DEACTIVATE = XInternAtom (si->dpy, "DEACTIVATE", False);
-  XA_RESTART = XInternAtom (si->dpy, "RESTART", False);
-  XA_CYCLE = XInternAtom (si->dpy, "CYCLE", False);
-  XA_NEXT = XInternAtom (si->dpy, "NEXT", False);
-  XA_PREV = XInternAtom (si->dpy, "PREV", False);
-  XA_EXIT = XInternAtom (si->dpy, "EXIT", False);
-  XA_DEMO = XInternAtom (si->dpy, "DEMO", False);
-  XA_PREFS = XInternAtom (si->dpy, "PREFS", False);
-  XA_LOCK = XInternAtom (si->dpy, "LOCK", False);
+/* Examine all of the display's screens, and populate the `saver_screen_info'
+   structures.
+ */
+static void
+initialize_per_screen_info (saver_info *si, Widget toplevel_shell)
+{
+  Bool found_any_writable_cells = False;
+  int i;
 
   si->nscreens = ScreenCount(si->dpy);
   si->screens = (saver_screen_info *)
     calloc(sizeof(saver_screen_info), si->nscreens);
 
-  si->default_screen = &si->screens[DefaultScreen(si->dpy)];
+  si->default_screen = &si->screens[DefaultScreen(si->dpy)];
+
+  for (i = 0; i < si->nscreens; i++)
+    {
+      saver_screen_info *ssi = &si->screens[i];
+      ssi->global = si;
+      ssi->screen = ScreenOfDisplay (si->dpy, i);
+
+      /* Note: we can't use the resource ".visual" because Xt is SO FUCKED. */
+      ssi->default_visual =
+	get_visual_resource (ssi->screen, "visualID", "VisualID", False);
+
+      ssi->current_visual = ssi->default_visual;
+      ssi->current_depth = visual_depth (ssi->screen, ssi->current_visual);
+
+      if (ssi == si->default_screen)
+	/* Since this is the default screen, use the one already created. */
+	ssi->toplevel_shell = toplevel_shell;
+      else
+	/* Otherwise, each screen must have its own unmapped root widget. */
+	ssi->toplevel_shell =
+	  XtVaAppCreateShell (progname, progclass, applicationShellWidgetClass,
+			      si->dpy,
+			      XtNscreen, ssi->screen,
+			      XtNvisual, ssi->current_visual,
+			      XtNdepth,  visual_depth (ssi->screen,
+						       ssi->current_visual),
+			      0);
+
+      if (! found_any_writable_cells)
+	{
+	  /* Check to see whether fading is ever possible -- if any of the
+	     screens on the display has a PseudoColor visual, then fading can
+	     work (on at least some screens.)  If no screen has a PseudoColor
+	     visual, then don't bother ever trying to fade, because it will
+	     just cause a delay without causing any visible effect.
+	  */
+	  if (has_writable_cells (ssi->screen, ssi->current_visual) ||
+	      get_visual (ssi->screen, "PseudoColor", True, False) ||
+	      get_visual (ssi->screen, "GrayScale", True, False))
+	    found_any_writable_cells = True;
+	}
+    }
+
+  si->prefs.fading_possible_p = found_any_writable_cells;
+}
+
+
+/* If any server extensions have been requested, try and initialize them.
+   Issue warnings if requests can't be honored.
+ */
+static void
+initialize_server_extensions (saver_info *si)
+{
+  saver_preferences *p = &si->prefs;
+
+  Bool server_has_xidle_extension_p = False;
+  Bool server_has_sgi_saver_extension_p = False;
+  Bool server_has_mit_saver_extension_p = False;
+  Bool system_has_proc_interrupts_p = False;
+  const char *piwhy = 0;
+
+  si->using_xidle_extension = p->use_xidle_extension;
+  si->using_sgi_saver_extension = p->use_sgi_saver_extension;
+  si->using_mit_saver_extension = p->use_mit_saver_extension;
+  si->using_proc_interrupts = p->use_proc_interrupts;
+
+#ifdef HAVE_XIDLE_EXTENSION
+  server_has_xidle_extension_p = query_xidle_extension (si);
+#endif
+#ifdef HAVE_SGI_SAVER_EXTENSION
+  server_has_sgi_saver_extension_p = query_sgi_saver_extension (si);
+#endif
+#ifdef HAVE_MIT_SAVER_EXTENSION
+  server_has_mit_saver_extension_p = query_mit_saver_extension (si);
+#endif
+#ifdef HAVE_PROC_INTERRUPTS
+  system_has_proc_interrupts_p = query_proc_interrupts_available (si, &piwhy);
+#endif
+
+  if (!server_has_xidle_extension_p)
+    si->using_xidle_extension = False;
+  else if (p->verbose_p)
+    {
+      if (si->using_xidle_extension)
+	fprintf (stderr, "%s: using XIDLE extension.\n", blurb());
+      else
+	fprintf (stderr, "%s: not using server's XIDLE extension.\n", blurb());
+    }
+
+  if (!server_has_sgi_saver_extension_p)
+    si->using_sgi_saver_extension = False;
+  else if (p->verbose_p)
+    {
+      if (si->using_sgi_saver_extension)
+	fprintf (stderr, "%s: using SGI SCREEN_SAVER extension.\n", blurb());
+      else
+	fprintf (stderr,
+		 "%s: not using server's SGI SCREEN_SAVER extension.\n",
+		 blurb());
+    }
+
+  if (!server_has_mit_saver_extension_p)
+    si->using_mit_saver_extension = False;
+  else if (p->verbose_p)
+    {
+      if (si->using_mit_saver_extension)
+	fprintf (stderr, "%s: using lame MIT-SCREEN-SAVER extension.\n",
+		 blurb());
+      else
+	fprintf (stderr,
+		 "%s: not using server's lame MIT-SCREEN-SAVER extension.\n",
+		 blurb());
+    }
+
+  if (!system_has_proc_interrupts_p)
+    {
+      si->using_proc_interrupts = False;
+      if (p->verbose_p && piwhy)
+	fprintf (stderr, "%s: not using /proc/interrupts: %s.\n", blurb(),
+                 piwhy);
+    }
+  else if (p->verbose_p)
+    {
+      if (si->using_proc_interrupts)
+	fprintf (stderr,
+                 "%s: consulting /proc/interrupts for keyboard activity.\n",
+		 blurb());
+      else
+	fprintf (stderr,
+                "%s: not consulting /proc/interrupts for keyboard activity.\n",
+		 blurb());
+    }
+}
+
+
+/* For the case where we aren't using an server extensions, select user events
+   on all the existing windows, and launch timers to select events on
+   newly-created windows as well.
+
+   If a server extension is being used, this does nothing.
+ */
+static void
+select_events (saver_info *si)
+{
+  saver_preferences *p = &si->prefs;
+  int i;
+
+  if (si->using_xidle_extension ||
+      si->using_mit_saver_extension ||
+      si->using_sgi_saver_extension)
+    return;
+
+  if (p->initial_delay)
+    {
+      if (p->verbose_p)
+	{
+	  fprintf (stderr, "%s: waiting for %d second%s...", blurb(),
+		   (int) p->initial_delay/1000,
+		   (p->initial_delay == 1000 ? "" : "s"));
+	  fflush (stderr);
+	  fflush (stdout);
+	}
+      usleep (p->initial_delay);
+      if (p->verbose_p)
+	fprintf (stderr, " done.\n");
+    }
 
-  for (i = 0; i < si->nscreens; i++)
+  if (p->verbose_p)
     {
-      saver_screen_info *ssi = &si->screens[i];
-      ssi->global = si;
-      ssi->screen = ScreenOfDisplay (si->dpy, i);
+      fprintf (stderr, "%s: selecting events on extant windows...", blurb());
+      fflush (stderr);
+      fflush (stdout);
+    }
 
-      /* Note: we can't use the resource ".visual" because Xt is SO FUCKED. */
-      ssi->default_visual =
-	get_visual_resource (ssi->screen, "visualID", "VisualID", False);
+  /* Select events on the root windows of every screen.  This also selects
+     for window creation events, so that new subwindows will be noticed.
+   */
+  for (i = 0; i < si->nscreens; i++)
+    start_notice_events_timer (si, RootWindowOfScreen (si->screens[i].screen),
+                               False);
 
-      ssi->current_visual = ssi->default_visual;
-      ssi->current_depth = visual_depth (ssi->screen, ssi->current_visual);
+  if (p->verbose_p)
+    fprintf (stderr, " done.\n");
+}
 
-      if (ssi == si->default_screen)
-	/* Since this is the default screen, use the one already created. */
-	ssi->toplevel_shell = toplevel_shell;
-      else
-	/* Otherwise, each screen must have its own unmapped root widget. */
-	ssi->toplevel_shell =
-	  XtVaAppCreateShell(progname, progclass, applicationShellWidgetClass,
-			     si->dpy,
-			     XtNscreen, ssi->screen,
-			     XtNvisual, ssi->current_visual,
-			     XtNdepth,  visual_depth(ssi->screen,
-						     ssi->current_visual),
-			     0);
+
+void
+maybe_reload_init_file (saver_info *si)
+{
+  saver_preferences *p = &si->prefs;
+  if (init_file_changed_p (p))
+    {
+      if (p->verbose_p)
+	fprintf (stderr, "%s: file \"%s\" has changed, reloading.\n",
+		 blurb(), init_file_name());
+
+      load_init_file (p);
+
+      /* If a server extension is in use, and p->timeout has changed,
+	 we need to inform the server of the new timeout. */
+      disable_builtin_screensaver (si, False);
     }
 }
 
 
+/* Loop forever:
+
+       - wait until the user is idle;
+       - blank the screen;
+       - wait until the user is active;
+       - unblank the screen;
+       - repeat.
+
+ */
 static void
-initialize (saver_info *si, int argc, char **argv)
+main_loop (saver_info *si)
 {
-  int i;
   saver_preferences *p = &si->prefs;
-  Bool initial_demo_mode_p = False;
-  si->version = (char *) malloc (5);
-  memcpy (si->version, screensaver_id + 17, 4);
-  si->version [4] = 0;
-  progname = argv[0]; /* reset later; this is for the benefit of lock_init() */
+  Bool ok_to_unblank;
 
-  if(strlen(progname) > 100) progname[99] = 0;  /* keep it short. */
+  while (1)
+    {
+      sleep_until_idle (si, True);
 
-#ifdef NO_LOCKING
-  si->locking_disabled_p = True;
-  si->nolock_reason = "not compiled with locking support";
-#else  /* !NO_LOCKING */
-  si->locking_disabled_p = False;
+      if (p->verbose_p)
+	{
+	  if (si->demoing_p)
+	    fprintf (stderr, "%s: demoing %d at %s.\n", blurb(),
+		     si->selection_mode, timestring());
+	  else
+	    if (p->verbose_p)
+	      fprintf (stderr, "%s: blanking screen at %s.\n", blurb(),
+		       timestring());
+	}
 
-# ifdef SCO
-  set_auth_parameters(argc, argv);
-# endif /* SCO */
+      maybe_reload_init_file (si);
 
-  if (! lock_init (argc, argv))	/* before hack_uid() for proper permissions */
-    {
-      si->locking_disabled_p = True;
-      si->nolock_reason = "error getting password";
-    }
-#endif  /* !NO_LOCKING */
+      if (! blank_screen (si))
+        {
+          /* We were unable to grab either the keyboard or mouse.
+             This means we did not (and must not) blank the screen.
+             If we were to blank the screen while some other program
+             is holding both the mouse and keyboard grabbed, then
+             we would never be able to un-blank it!  We would never
+             see any events, and the display would be wedged.
 
-#ifndef NO_SETUID
-  hack_uid (si);
-#endif /* NO_SETUID */
+             So, just go around the loop again and wait for the
+             next bout of idleness.
+          */
 
-  progclass = "XScreenSaver";
+          fprintf (stderr,
+                  "%s: unable to grab keyboard or mouse!  Blanking aborted.\n",
+                   blurb());
+          continue;
+        }
 
-  /* remove -initial-demo-mode switch before saving argv */
-  for (i = 1; i < argc; i++)
-    while (!strcmp ("-initial-demo-mode", argv [i]))
-      {
-	int j;
-	initial_demo_mode_p = True;
-	for (j = i; j < argc; j++)
-	  argv [j] = argv [j+1];
-	argv [j] = 0;
-	argc--;
-	if (argc <= i) break;
-      }
-  save_argv (argc, argv);
-  initialize_connection (si, argc, argv);
+      kill_screenhack (si);
+      spawn_screenhack (si, True);
 
-  if (p->verbose_p)
-    fprintf (stderr, "\
-%s %s, copyright (c) 1991-1998 by Jamie Zawinski <jwz@jwz.org>\n\
- pid = %d.\n", progname, si->version, (int) getpid ());
+      /* Don't start the cycle timer in demo mode. */
+      if (!si->demoing_p && p->cycle)
+	si->cycle_id = XtAppAddTimeOut (si->app, p->cycle, cycle_timer,
+					(XtPointer) si);
 
-  
-  for (i = 0; i < si->nscreens; i++)
-    if (ensure_no_screensaver_running (si->dpy, si->screens[i].screen))
-      exit (1);
 
-  hack_environment (si);
+#ifndef NO_LOCKING
+      if (!si->demoing_p &&		/* if not going into demo mode */
+	  p->lock_p &&			/* and locking is enabled */
+	  !si->locking_disabled_p &&	/* and locking is possible */
+	  p->lock_timeout == 0)		/* and locking is not timer-deferred */
+	si->locked_p = True;		/* then lock right now. */
+
+      /* locked_p might be true already because of the above, or because of
+	 the LOCK ClientMessage.  But if not, and if we're supposed to lock
+	 after some time, set up a timer to do so.
+       */
+      if (p->lock_p &&
+	  !si->locked_p &&
+	  p->lock_timeout > 0)
+	si->lock_id = XtAppAddTimeOut (si->app, p->lock_timeout,
+				       activate_lock_timer,
+				       (XtPointer) si);
+#endif /* !NO_LOCKING */
 
-  si->demo_mode_p = initial_demo_mode_p;
-  srandom ((int) time ((time_t *) 0));
 
-  if (p->debug_p)
-    fprintf (stderr, "\n"
-	     "%s: Warning: running in DEBUG MODE.  Be afraid.\n"
-	     "\n"
-	     "\tNote that in debug mode, the xscreensaver window will only\n"
-	     "\tcover the left half of the screen.  (The idea is that you\n"
-	     "\tcan still see debugging output in a shell, if you position\n"
-	     "\tit on the right side of the screen.)\n"
-	     "\n"
-	     "\tDebug mode is NOT SECURE.  Do not run with -debug in\n"
-	     "\tuntrusted environments.\n"
-	     "\n",
-	     progname);
+      ok_to_unblank = True;
+      do {
 
-  if (p->use_sgi_saver_extension)
-    {
-#ifdef HAVE_SGI_SAVER_EXTENSION
-      if (! query_sgi_saver_extension (si))
-	{
-	  fprintf (stderr,
-	 "%s: display %s does not support the SGI SCREEN_SAVER extension.\n",
-		   blurb(), DisplayString (si->dpy));
-	  p->use_sgi_saver_extension = False;
-	}
-      else if (p->use_mit_saver_extension)
-	{
-	  fprintf (stderr, "%s: SGI SCREEN_SAVER extension used instead\
- of MIT-SCREEN-SAVER extension.\n",
-		   blurb());
-	  p->use_mit_saver_extension = False;
-	}
-      else if (p->use_xidle_extension)
-	{
-	  fprintf (stderr,
-	 "%s: SGI SCREEN_SAVER extension used instead of XIDLE extension.\n",
-		   blurb());
-	  p->use_xidle_extension = False;
-	}
-#else  /* !HAVE_MIT_SAVER_EXTENSION */
-      fprintf (stderr,
-       "%s: not compiled with support for the SGI SCREEN_SAVER extension.\n",
-	       blurb());
-      p->use_sgi_saver_extension = False;
-#endif /* !HAVE_SGI_SAVER_EXTENSION */
-    }
+	sleep_until_idle (si, False);		/* until not idle */
+	maybe_reload_init_file (si);
 
-  if (p->use_mit_saver_extension)
-    {
-#ifdef HAVE_MIT_SAVER_EXTENSION
-      if (! query_mit_saver_extension (si))
-	{
-	  fprintf (stderr,
-	 "%s: display %s does not support the MIT-SCREEN-SAVER extension.\n",
-		   blurb(), DisplayString (si->dpy));
-	  p->use_mit_saver_extension = False;
-	}
-      else if (p->use_xidle_extension)
-	{
-	  fprintf (stderr,
-	 "%s: MIT-SCREEN-SAVER extension used instead of XIDLE extension.\n",
-		   blurb());
-	  p->use_xidle_extension = False;
-	}
-#else  /* !HAVE_MIT_SAVER_EXTENSION */
-      fprintf (stderr,
-       "%s: not compiled with support for the MIT-SCREEN-SAVER extension.\n",
-	       blurb());
-      p->use_mit_saver_extension = False;
-#endif /* !HAVE_MIT_SAVER_EXTENSION */
-    }
+#ifndef NO_LOCKING
+	if (si->locked_p)
+	  {
+	    saver_screen_info *ssi = si->default_screen;
+	    if (si->locking_disabled_p) abort ();
 
-  if (p->use_xidle_extension)
-    {
-#ifdef HAVE_XIDLE_EXTENSION
-      int first_event, first_error;
-      if (! XidleQueryExtension (si->dpy, &first_event, &first_error))
-	{
-	  fprintf (stderr,
-		   "%s: display %s does not support the XIdle extension.\n",
-		   blurb(), DisplayString (si->dpy));
-	  p->use_xidle_extension = False;
-	}
-#else  /* !HAVE_XIDLE_EXTENSION */
-      fprintf (stderr, "%s: not compiled with support for XIdle.\n",
-	       blurb());
-      p->use_xidle_extension = False;
-#endif /* !HAVE_XIDLE_EXTENSION */
-    }
+	    si->dbox_up_p = True;
+	    suspend_screenhack (si, True);
+	    XUndefineCursor (si->dpy, ssi->screensaver_window);
 
-  /* Call this only after having probed for presence of desired extension. */
-  initialize_screensaver_window (si);
+	    ok_to_unblank = unlock_p (si);
 
-  init_sigchld ();
+	    si->dbox_up_p = False;
+	    XDefineCursor (si->dpy, ssi->screensaver_window, ssi->cursor);
+	    suspend_screenhack (si, False);	/* resume */
+	  }
+#endif /* !NO_LOCKING */
 
-  disable_builtin_screensaver (si, True);
+	} while (!ok_to_unblank);
 
-  if (p->verbose_p && p->use_mit_saver_extension)
-    fprintf (stderr, "%s: using MIT-SCREEN-SAVER server extension.\n",
-	     blurb());
-  if (p->verbose_p && p->use_sgi_saver_extension)
-    fprintf (stderr, "%s: using SGI SCREEN_SAVER server extension.\n",
-	     blurb());
-  if (p->verbose_p && p->use_xidle_extension)
-    fprintf (stderr, "%s: using XIdle server extension.\n",
-	     blurb());
 
-  initialize_stderr (si);
-  XSetErrorHandler (saver_ehandler);
+      if (p->verbose_p)
+	fprintf (stderr, "%s: unblanking screen at %s.\n",
+		 blurb(), timestring ());
 
-  if (initial_demo_mode_p)
-    /* If the user wants demo mode, don't wait around before doing it. */
-    p->initial_delay = 0;
+      /* Kill before unblanking, to stop drawing as soon as possible. */
+      kill_screenhack (si);
+      unblank_screen (si);
 
-  if (!p->use_xidle_extension &&
-      !p->use_mit_saver_extension &&
-      !p->use_sgi_saver_extension)
-    {
-      if (p->initial_delay)
+      si->locked_p = False;
+      si->demoing_p = 0;
+      si->selection_mode = 0;
+
+      if (si->cycle_id)
 	{
-	  if (p->verbose_p)
-	    {
-	      fprintf (stderr, "%s: waiting for %d second%s...", blurb(),
-		       (int) p->initial_delay,
-		       (p->initial_delay == 1 ? "" : "s"));
-	      fflush (stderr);
-	      fflush (stdout);
-	    }
-	  sleep (p->initial_delay);
-	  if (p->verbose_p)
-	    fprintf (stderr, " done.\n");
+	  XtRemoveTimeOut (si->cycle_id);
+	  si->cycle_id = 0;
 	}
-      if (p->verbose_p)
+
+      if (si->lock_id)
 	{
-	  fprintf (stderr, "%s: selecting events on extant windows...",
-		   blurb());
-	  fflush (stderr);
-	  fflush (stdout);
+	  XtRemoveTimeOut (si->lock_id);
+	  si->lock_id = 0;
 	}
 
-      /* Select events on the root windows of every screen.  This also selects
-	 for window creation events, so that new subwindows will be noticed.
-       */
-      for (i = 0; i < si->nscreens; i++)
-	start_notice_events_timer (si,
-				   RootWindowOfScreen (si->screens[i].screen));
-
       if (p->verbose_p)
-	fprintf (stderr, " done.\n");
+	fprintf (stderr, "%s: awaiting idleness.\n", blurb());
     }
 }
 
-static void
-main_loop (saver_info *si)
+static void analyze_display (saver_info *si);
+
+int
+main (int argc, char **argv)
 {
+  Widget shell;
+  saver_info the_si;
+  saver_info *si = &the_si;
   saver_preferences *p = &si->prefs;
-  while (1)
-    {
-      if (! si->demo_mode_p)
-	sleep_until_idle (si, True);
+  int i;
 
-#ifndef NO_DEMO_MODE
-      if (si->demo_mode_p)
-	demo_mode (si);
-      else
-#endif /* !NO_DEMO_MODE */
-	{
-	  if (p->verbose_p)
-	    fprintf (stderr, "%s: user is idle; waking up at %s.\n", blurb(),
-		     timestring());
-	  blank_screen (si);
-	  spawn_screenhack (si, True);
-	  if (p->cycle)
-	    si->cycle_id = XtAppAddTimeOut (si->app, p->cycle, cycle_timer,
-					    (XtPointer) si);
+  memset(si, 0, sizeof(*si));
+  global_si_kludge = si;	/* I hate C so much... */
 
-#ifndef NO_LOCKING
-	  if (p->lock_p && p->lock_timeout == 0)
-	    si->locked_p = True;
-	  if (p->lock_p && !si->locked_p)
-	    /* locked_p might be true already because of ClientMessage */
-	    si->lock_id = XtAppAddTimeOut (si->app, p->lock_timeout,
-					   activate_lock_timer,
-					   (XtPointer) si);
-#endif /* !NO_LOCKING */
+  srandom ((int) time ((time_t *) 0));
 
-	PASSWD_INVALID:
+  save_argv (argc, argv);
+  set_version_string (si, &argc, argv);
+  privileged_initialization (si, &argc, argv);
+  hack_environment (si);
 
-	  sleep_until_idle (si, False); /* until not idle */
+  shell = connect_to_server (si, &argc, argv);
+  process_command_line (si, &argc, argv);
+  print_banner (si);
 
-#ifndef NO_LOCKING
-	  if (si->locked_p)
-	    {
-	      Bool val;
-	      if (si->locking_disabled_p) abort ();
-	      si->dbox_up_p = True;
-
-	      {
-		saver_screen_info *ssi = si->default_screen;
-		suspend_screenhack (si, True);
-		XUndefineCursor (si->dpy, ssi->screensaver_window);
-		if (p->verbose_p)
-		  fprintf (stderr, "%s: prompting for password.\n", blurb());
-		val = unlock_p (si);
-		if (p->verbose_p && val == False)
-		  fprintf (stderr, "%s: password incorrect!\n", blurb());
-		si->dbox_up_p = False;
-		XDefineCursor (si->dpy, ssi->screensaver_window, ssi->cursor);
-		suspend_screenhack (si, False);
-	      }
-
-	      if (! val)
-		goto PASSWD_INVALID;
-	      si->locked_p = False;
-	    }
-#endif /* !NO_LOCKING */
+  initialize_per_screen_info (si, shell);  /* also sets p->fading_possible_p */
 
-	  if (p->verbose_p)
-	    fprintf (stderr, "%s: user is active at %s.\n",
-		     blurb(), timestring ());
+  for (i = 0; i < si->nscreens; i++)
+    if (ensure_no_screensaver_running (si->dpy, si->screens[i].screen))
+      exit (1);
 
-	  /* Let's kill it before unblanking, to get it to stop drawing as
-	     soon as possible... */
-	  kill_screenhack (si);
-	  unblank_screen (si);
+  load_init_file (p);
+  lock_initialization (si, &argc, argv);
 
-	  if (si->cycle_id)
-	    {
-	      XtRemoveTimeOut (si->cycle_id);
-	      si->cycle_id = 0;
-	    }
+  if (p->xsync_p) XSynchronize (si->dpy, True);
+  blurb_timestamp_p = p->timestamp_p;  /* kludge */
 
-#ifndef NO_LOCKING
-	  if (si->lock_id)
-	    {
-	      XtRemoveTimeOut (si->lock_id);
-	      si->lock_id = 0;
-	    }
-#endif /* !NO_LOCKING */
+  if (p->verbose_p) analyze_display (si);
+  initialize_server_extensions (si);
+  initialize_screensaver_window (si);
+  select_events (si);
+  init_sigchld ();
+  disable_builtin_screensaver (si, True);
+  initialize_stderr (si);
 
-	  if (p->verbose_p)
-	    fprintf (stderr, "%s: going to sleep.\n", blurb());
-	}
-    }
+  make_splash_dialog (si);
+
+  main_loop (si);		/* doesn't return */
+  return 0;
 }
 
 
+/* Processing ClientMessage events.
+ */
+
+static void
+clientmessage_response (saver_info *si, Window w, Bool error,
+			const char *stderr_msg,
+			const char *protocol_msg)
+{
+  char *proto;
+  int L;
+  saver_preferences *p = &si->prefs;
+  if (error || p->verbose_p)
+    fprintf (stderr, "%s: %s\n", blurb(), stderr_msg);
+
+  L = strlen(protocol_msg);
+  proto = (char *) malloc (L + 2);
+  proto[0] = (error ? '-' : '+');
+  strcpy (proto+1, protocol_msg);
+  L++;
+
+  XChangeProperty (si->dpy, w, XA_SCREENSAVER_RESPONSE, XA_STRING, 8,
+		   PropModeReplace, (unsigned char *) proto, L);
+  XSync (si->dpy, False);
+  free (proto);
+}
 
 Bool
 handle_clientmessage (saver_info *si, XEvent *event, Bool until_idle_p)
 {
-  saver_preferences *p = &si->prefs;
   Atom type = 0;
+  Window window = event->xclient.window;
+
+  /* Preferences might affect our handling of client messages. */
+  maybe_reload_init_file (si);
+
   if (event->xclient.message_type != XA_SCREENSAVER)
     {
       char *str;
@@ -1069,10 +1108,12 @@ handle_clientmessage (saver_info *si, XEvent *event, Bool until_idle_p)
     {
       if (until_idle_p)
 	{
-	  if (p->verbose_p)
-	    fprintf (stderr,
-		     "%s: ACTIVATE ClientMessage received.\n", blurb());
-	  if (p->use_mit_saver_extension || p->use_sgi_saver_extension)
+	  clientmessage_response(si, window, False,
+				 "ACTIVATE ClientMessage received.",
+				 "activating.");
+	  si->selection_mode = 0;
+	  si->demoing_p = False;
+	  if (si->using_mit_saver_extension || si->using_sgi_saver_extension)
 	    {
 	      XForceScreenSaver (si->dpy, ScreenSaverActive);
 	      return False;
@@ -1082,18 +1123,18 @@ handle_clientmessage (saver_info *si, XEvent *event, Bool until_idle_p)
 	      return True;
 	    }
 	}
-      fprintf (stderr,
-	       "%s: ClientMessage ACTIVATE received while already active.\n",
-	       blurb());
+      clientmessage_response(si, window, True,
+		       "ClientMessage ACTIVATE received while already active.",
+			     "already active.");
     }
   else if (type == XA_DEACTIVATE)
     {
       if (! until_idle_p)
 	{
-	  if (p->verbose_p)
-	    fprintf (stderr, "%s: DEACTIVATE ClientMessage received.\n",
-		     blurb());
-	  if (p->use_mit_saver_extension || p->use_sgi_saver_extension)
+	  clientmessage_response(si, window, False,
+				 "DEACTIVATE ClientMessage received.",
+				 "deactivating.");
+	  if (si->using_mit_saver_extension || si->using_sgi_saver_extension)
 	    {
 	      XForceScreenSaver (si->dpy, ScreenSaverReset);
 	      return False;
@@ -1103,31 +1144,62 @@ handle_clientmessage (saver_info *si, XEvent *event, Bool until_idle_p)
 	      return True;
 	    }
 	}
-      fprintf (stderr,
-	       "%s: ClientMessage DEACTIVATE received while inactive.\n",
-	       blurb());
+      clientmessage_response(si, window, True,
+			   "ClientMessage DEACTIVATE received while inactive.",
+			     "not active.");
     }
   else if (type == XA_CYCLE)
     {
       if (! until_idle_p)
 	{
-	  if (p->verbose_p)
-	    fprintf (stderr, "%s: CYCLE ClientMessage received.\n", blurb());
+	  clientmessage_response(si, window, False,
+				 "CYCLE ClientMessage received.",
+				 "cycling.");
+	  si->selection_mode = 0;	/* 0 means randomize when its time. */
+	  si->demoing_p = False;
 	  if (si->cycle_id)
 	    XtRemoveTimeOut (si->cycle_id);
 	  si->cycle_id = 0;
 	  cycle_timer ((XtPointer) si, 0);
 	  return False;
 	}
-      fprintf (stderr, "%s: ClientMessage CYCLE received while inactive.\n",
-	       blurb());
+      clientmessage_response(si, window, True,
+			     "ClientMessage CYCLE received while inactive.",
+			     "not active.");
     }
   else if (type == XA_NEXT || type == XA_PREV)
     {
-      if (p->verbose_p)
-	fprintf (stderr, "%s: %s ClientMessage received.\n", blurb(),
-		(type == XA_NEXT ? "NEXT" : "PREV"));
-      si->next_mode_p = 1 + (type == XA_PREV);
+      clientmessage_response(si, window, False,
+			     (type == XA_NEXT
+			      ? "NEXT ClientMessage received."
+			      : "PREV ClientMessage received."),
+			     "cycling.");
+      si->selection_mode = (type == XA_NEXT ? -1 : -2);
+      si->demoing_p = False;
+
+      if (! until_idle_p)
+	{
+	  if (si->cycle_id)
+	    XtRemoveTimeOut (si->cycle_id);
+	  si->cycle_id = 0;
+	  cycle_timer ((XtPointer) si, 0);
+	}
+      else
+	return True;
+    }
+  else if (type == XA_SELECT)
+    {
+      char buf [255];
+      char buf2 [255];
+      long which = event->xclient.data.l[1];
+
+      sprintf (buf, "SELECT %ld ClientMessage received.", which);
+      sprintf (buf2, "activating (%ld).", which);
+      clientmessage_response (si, window, False, buf, buf2);
+
+      if (which < 0) which = 0;		/* 0 == "random" */
+      si->selection_mode = which;
+      si->demoing_p = False;
 
       if (! until_idle_p)
 	{
@@ -1144,8 +1216,9 @@ handle_clientmessage (saver_info *si, XEvent *event, Bool until_idle_p)
       /* Ignore EXIT message if the screen is locked. */
       if (until_idle_p || !si->locked_p)
 	{
-	  if (p->verbose_p)
-	    fprintf (stderr, "%s: EXIT ClientMessage received.\n", blurb());
+	  clientmessage_response (si, window, False,
+				  "EXIT ClientMessage received.",
+				  "exiting.");
 	  if (! until_idle_p)
 	    {
 	      unblank_screen (si);
@@ -1155,8 +1228,9 @@ handle_clientmessage (saver_info *si, XEvent *event, Bool until_idle_p)
 	  saver_exit (si, 0, 0);
 	}
       else
-	fprintf (stderr, "%s: EXIT ClientMessage received while locked.\n",
-		 blurb());
+	clientmessage_response (si, window, True,
+				"EXIT ClientMessage received while locked.",
+				"screen is locked.");
     }
   else if (type == XA_RESTART)
     {
@@ -1165,8 +1239,9 @@ handle_clientmessage (saver_info *si, XEvent *event, Bool until_idle_p)
        */
       if (until_idle_p || !si->locked_p)
 	{
-	  if (p->verbose_p)
-	    fprintf (stderr, "%s: RESTART ClientMessage received.\n", blurb());
+	  clientmessage_response (si, window, False,
+				  "RESTART ClientMessage received.",
+				  "restarting.");
 	  if (! until_idle_p)
 	    {
 	      unblank_screen (si);
@@ -1183,63 +1258,76 @@ handle_clientmessage (saver_info *si, XEvent *event, Bool until_idle_p)
 			   make this command be the same as EXIT. */
 	}
       else
-	fprintf(stderr, "%s: RESTART ClientMessage received while locked.\n",
-		blurb());
+	clientmessage_response (si, window, True,
+				"RESTART ClientMessage received while locked.",
+				"screen is locked.");
     }
   else if (type == XA_DEMO)
     {
-#ifdef NO_DEMO_MODE
-      fprintf (stderr, "%s: not compiled with support for DEMO mode\n",
-	       blurb());
-#else
-      if (until_idle_p)
+      long arg = event->xclient.data.l[1];
+      Bool demo_one_hack_p = (arg == 300);
+
+      if (demo_one_hack_p)
+	{
+	  if (until_idle_p)
+	    {
+	      long which = event->xclient.data.l[2];
+	      char buf [255];
+	      char buf2 [255];
+	      sprintf (buf, "DEMO %ld ClientMessage received.", which);
+	      sprintf (buf2, "demoing (%ld).", which);
+	      clientmessage_response (si, window, False, buf, buf2);
+
+	      if (which < 0) which = 0;		/* 0 == "random" */
+	      si->selection_mode = which;
+	      si->demoing_p = True;
+
+	      return True;
+	    }
+
+	  clientmessage_response (si, window, True,
+				  "DEMO ClientMessage received while active.",
+				  "already active.");
+	}
+      else
 	{
-	  if (p->verbose_p)
-	    fprintf (stderr, "%s: DEMO ClientMessage received.\n", blurb());
-	  si->demo_mode_p = True;
-	  return True;
+	  clientmessage_response (si, window, True,
+				  "obsolete form of DEMO ClientMessage.",
+				  "obsolete form of DEMO ClientMessage.");
 	}
-      fprintf (stderr,
-	       "%s: DEMO ClientMessage received while active.\n", blurb());
-#endif
     }
   else if (type == XA_PREFS)
     {
-#ifdef NO_DEMO_MODE
-      fprintf (stderr, "%s: not compiled with support for DEMO mode\n",
-	       blurb());
-#else
-      if (until_idle_p)
-	{
-	  if (p->verbose_p)
-	    fprintf (stderr, "%s: PREFS ClientMessage received.\n", blurb());
-	  si->demo_mode_p = (Bool) 2;  /* kludge, so sue me. */
-	  return True;
-	}
-      fprintf (stderr,
-	       "%s: PREFS ClientMessage received while active.\n", blurb());
-#endif
+      clientmessage_response (si, window, True,
+			      "the PREFS client-message is obsolete.",
+			      "the PREFS client-message is obsolete.");
     }
   else if (type == XA_LOCK)
     {
 #ifdef NO_LOCKING
-      fprintf (stderr, "%s: not compiled with support for LOCK mode\n",
-	       blurb());
-#else
+      clientmessage_response (si, window, True,
+			      "not compiled with support for locking.",
+			      "locking not enabled.");
+#else /* !NO_LOCKING */
       if (si->locking_disabled_p)
-	fprintf (stderr,
-	       "%s: LOCK ClientMessage received, but locking is disabled.\n",
-		 blurb());
+	clientmessage_response (si, window, True,
+		      "LOCK ClientMessage received, but locking is disabled.",
+			      "locking not enabled.");
       else if (si->locked_p)
-	fprintf (stderr,
-	       "%s: LOCK ClientMessage received while already locked.\n",
-		 blurb());
+	clientmessage_response (si, window, True,
+			   "LOCK ClientMessage received while already locked.",
+				"already locked.");
       else
 	{
+	  char buf [255];
+	  char *response = (until_idle_p
+			    ? "activating and locking."
+			    : "locking.");
 	  si->locked_p = True;
-	  if (p->verbose_p) 
-	    fprintf (stderr, "%s: LOCK ClientMessage received;%s locking.\n",
-		    blurb(), until_idle_p ? " activating and" : "");
+	  si->selection_mode = 0;
+	  si->demoing_p = False;
+	  sprintf (buf, "LOCK ClientMessage received; %s", response);
+	  clientmessage_response (si, window, False, buf, response);
 
 	  if (si->lock_id)	/* we're doing it now, so lose the timeout */
 	    {
@@ -1249,7 +1337,8 @@ handle_clientmessage (saver_info *si, XEvent *event, Bool until_idle_p)
 
 	  if (until_idle_p)
 	    {
-	      if (p->use_mit_saver_extension || p->use_sgi_saver_extension)
+	      if (si->using_mit_saver_extension ||
+                  si->using_sgi_saver_extension)
 		{
 		  XForceScreenSaver (si->dpy, ScreenSaverActive);
 		  return False;
@@ -1260,21 +1349,146 @@ handle_clientmessage (saver_info *si, XEvent *event, Bool until_idle_p)
 		}
 	    }
 	}
-#endif
+#endif /* !NO_LOCKING */
     }
   else
     {
+      char buf [1024];
       char *str;
       str = (type ? XGetAtomName(si->dpy, type) : 0);
+
       if (str)
-	fprintf (stderr,
-		 "%s: unrecognised screensaver ClientMessage %s received\n",
-		 blurb(), str);
+	{
+	  if (strlen (str) > 80)
+	    strcpy (str+70, "...");
+	  sprintf (buf, "unrecognised screensaver ClientMessage %s received.",
+		   str);
+	  free (str);
+	}
       else
-	fprintf (stderr,
-		"%s: unrecognised screensaver ClientMessage 0x%x received\n",
-		 blurb(), (unsigned int) event->xclient.data.l[0]);
-      if (str) XFree (str);
+	{
+	  sprintf (buf,
+		   "unrecognised screensaver ClientMessage 0x%x received.",
+		   (unsigned int) event->xclient.data.l[0]);
+	}
+
+      clientmessage_response (si, window, True, buf, buf);
     }
   return False;
 }
+
+
+/* Some random diagnostics printed in -verbose mode.
+ */
+
+static void
+analyze_display (saver_info *si)
+{
+  int i, j;
+  static const char *exts[][2] = {
+    { "SCREEN_SAVER",	   "SGI Screen-Saver" },
+    { "SCREEN-SAVER",	   "SGI Screen-Saver" },
+    { "MIT-SCREEN-SAVER",  "MIT Screen-Saver" },
+    { "XIDLE",		   "XIdle" },
+    { "SGI-VIDEO-CONTROL", "SGI Video-Control" },
+    { "READDISPLAY",	   "SGI Read-Display" },
+    { "MIT-SHM",	   "Shared Memory" },
+    { "DOUBLE-BUFFER",	   "Double-Buffering" },
+    { "DPMS",		   "Power Management" },
+    { "GLX",		   "GLX" }
+  };
+
+  fprintf (stderr, "%s: running on display \"%s\"\n", blurb(),
+	   DisplayString(si->dpy));
+  fprintf (stderr, "%s: vendor is %s, %d\n", blurb(),
+	   ServerVendor(si->dpy), VendorRelease(si->dpy));
+
+  fprintf (stderr, "%s: useful extensions:\n", blurb());
+  for (i = 0; i < countof(exts); i++)
+    {
+      int op = 0, event = 0, error = 0;
+      if (XQueryExtension (si->dpy, exts[i][0], &op, &event, &error))
+	fprintf (stderr, "%s:   %s\n", blurb(), exts[i][1]);
+    }
+
+  for (i = 0; i < si->nscreens; i++)
+    {
+      unsigned long colormapped_depths = 0;
+      unsigned long non_mapped_depths = 0;
+      XVisualInfo vi_in, *vi_out;
+      int out_count;
+      vi_in.screen = i;
+      vi_out = XGetVisualInfo (si->dpy, VisualScreenMask, &vi_in, &out_count);
+      if (!vi_out) continue;
+      for (j = 0; j < out_count; j++)
+	if (vi_out[j].class == PseudoColor)
+	  colormapped_depths |= (1 << vi_out[j].depth);
+	else
+	  non_mapped_depths  |= (1 << vi_out[j].depth);
+      XFree ((char *) vi_out);
+
+      if (colormapped_depths)
+	{
+	  fprintf (stderr, "%s: screen %d colormapped depths:", blurb(), i);
+	  for (j = 0; j < 32; j++)
+	    if (colormapped_depths & (1 << j))
+	      fprintf (stderr, " %d", j);
+	  fprintf (stderr, "\n");
+	}
+      if (non_mapped_depths)
+	{
+	  fprintf (stderr, "%s: screen %d non-mapped depths:", blurb(), i);
+	  for (j = 0; j < 32; j++)
+	    if (non_mapped_depths & (1 << j))
+	      fprintf (stderr, " %d", j);
+	  fprintf (stderr, "\n");
+	}
+    }
+}
+
+Bool
+display_is_on_console_p (saver_info *si)
+{
+  Bool not_on_console = True;
+  char *dpystr = DisplayString (si->dpy);
+  char *tail = (char *) strchr (dpystr, ':');
+  if (! tail || strncmp (tail, ":0", 2))
+    not_on_console = True;
+  else
+    {
+      char dpyname[255], localname[255];
+      strncpy (dpyname, dpystr, tail-dpystr);
+      dpyname [tail-dpystr] = 0;
+      if (!*dpyname ||
+	  !strcmp(dpyname, "unix") ||
+	  !strcmp(dpyname, "localhost"))
+	not_on_console = False;
+      else if (gethostname (localname, sizeof (localname)))
+	not_on_console = True;  /* can't find hostname? */
+      else
+	{
+	  /* We have to call gethostbyname() on the result of gethostname()
+	     because the two aren't guarenteed to be the same name for the
+	     same host: on some losing systems, one is a FQDN and the other
+	     is not.  Here in the wide wonderful world of Unix it's rocket
+	     science to obtain the local hostname in a portable fashion.
+	     
+	     And don't forget, gethostbyname() reuses the structure it
+	     returns, so we have to copy the fucker before calling it again.
+	     Thank you master, may I have another.
+	   */
+	  struct hostent *h = gethostbyname (dpyname);
+	  if (!h)
+	    not_on_console = True;
+	  else
+	    {
+	      char hn [255];
+	      struct hostent *l;
+	      strcpy (hn, h->h_name);
+	      l = gethostbyname (localname);
+	      not_on_console = (!l || !!(strcmp (l->h_name, hn)));
+	    }
+	}
+    }
+  return !not_on_console;
+}