Add in all that stuff the last commit talked about

Makefile

@@ -1,8 +1,14 @@
+BINDIR = $(HOME)/bin
 CFLAGS = -Wall
 LDLIBS = -lX11
 
-all: xss xsswin xcursorpos xkeygrab magic
+BINARIES = xss xsswin xcursorpos xkeygrab xbell magic
+
+all: $(BINARIES)
+
+install: $(BINARIES)
+	cp $(BINARIES) $(BINDIR)
 
 xss: LDLIBS += -lXss
 
-.PHONY: all
+.PHONY: all install

README

@@ -1,6 +1,6 @@
 == xss ==
 
-`xss` uses the nearly 20-year-old MIT-SCREEN-SAVER extension to launch a
+`xss` uses the decades-old MIT-SCREEN-SAVER extension to launch a
 program when the X server turns on the built-in screen saver.
 
 `xsswin` makes a full-screen black window and runs some other program,
@@ -12,6 +12,8 @@ stdout.
 
 `xcursorpos` prints out the x and y coordinates of the cursor.
 
+`xbell` sounds the X server's bell.
+
 `magic` is a reimplementation of the "magic" screen saver from After
 Dark.  It probably doesn't work with an 8-bit color pallette.
 
@@ -28,18 +30,42 @@ Run like `xautolock`:
 
     xss xlock -mode qix &
 
+Launch a program called "screenlock" when you're idle:
 
-Shell script to run `magic` while waiting for a pass word from the keybord.  Won't
-do anything if the cursor is in the upper-left corner:
+    xss screenlock
+
+An simple "screenlock" script:
 
     #! /bin/sh
     
-    xcursorpos | (read x y; [ $x -lt 20 -a $y -lt 20 ]) && exit 0
-    xsswin magic XSS_WINDOW &
-    pid=$!
+    xsswin magic XSS_WINDOW & pid=$!
     xkeygrab | (while read l; do [ "$l" != "secret" ] && break; done)
     kill $pid
 
+A more complex "screenlock" script which locks the screen awaiting a
+pass phrase with the right md5 checksum.  After 4 seconds of being
+locked, it pauses mpd (iff it was playing).  When the screen is
+unlocked, mpd is resumed (iff it was playing beforehand).  The script
+won't lock if the cursor's at the top of the screen.
+
+    #! /bin/sh
+    
+    xcursorpos | (read x y; [ $y -lt 20 ]) && exit 0
+    mpc | fgrep -q '[playing]' && playing=1
+    xsswin magic XSS_WINDOW 2>/dev/null & xsswin=$!
+    (sleep 4; [ $playing ] && kill -0 $xsswin 2>/dev/null && mpc --no-status pause) &
+    xkeygrab | (
+        while read l; do
+            md5s=$(echo -n $l | md5sum | cut -d\  -f1)
+            if [ $md5s = 'a37c87558d98e9fe0484e09070268be1' ]; then
+                break
+            fi
+            xbell
+        done
+        )
+    kill $xsswin
+    [ $playing ] && mpc --no-status play
+
 
 Download
 --------
@@ -50,6 +76,13 @@ commit](http://woozle.org/~neale/repos/?p=xss;a=snapshot) or use git:
     git clone http://woozle.org/~neale/repos/xss/
 
 
+Bugs
+----
+
+* Sometimes xss quits launching anything.  I suspect it's not getting
+  SIGCHLD for some reason.
+
+
 History
 -------
 

xkeygrab.c

@@ -40,34 +40,34 @@ main(int argc, char *argv[])
     char          obuf[4096];
     int           obuflen = 0;
     struct pollfd fds[2];
-    int           i;
 
     if (! (display = XOpenDisplay(NULL))) raise("cannot open display");
     root = DefaultRootWindow(display);
-    for (i = 0; i < 3; ) {
-      if ((! (i & 1)) && (GrabSuccess == XGrabKeyboard(display, root,
-                                                       True,
-                                                       GrabModeAsync, GrabModeAsync,
-                                                       CurrentTime))) {
-        i |= 1;
-      }
-      if ((! (i & 2)) && (GrabSuccess == XGrabPointer(display, root,
-                                                      False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
-                                                      GrabModeAsync, GrabModeAsync,
-                                                      None, None, CurrentTime))) {
-        i |= 2;
-      }
-      (void)poll(NULL, 0, 100);
-    }
 
     fds[0].fd = STDOUT_FILENO;
     fds[0].events = 0;
     fds[1].fd = ConnectionNumber(display);
     fds[1].events = POLLIN;
     while (1) {
+      int tograb = 3;
       int ret;
 
-      ret = poll(fds, 2, -1);
+      if (tograb) {
+        if ((tograb & 1) && (GrabSuccess == XGrabKeyboard(display, root,
+                                                          True,
+                                                          GrabModeAsync, GrabModeAsync,
+                                                          CurrentTime))) {
+          tograb |= 1;
+        }
+        if ((tograb & 2) && (GrabSuccess == XGrabPointer(display, root,
+                                                         False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
+                                                         GrabModeAsync, GrabModeAsync,
+                                                         None, None, CurrentTime))) {
+          tograb |= 2;
+        }
+      }
+
+      ret = poll(fds, 2, (tograb?100:-1));
 
       if (fds[0].revents & POLLERR) {
         break;

xss.c

@@ -63,9 +63,7 @@ main(int argc, char *argv[])
     root = RootWindow(display, screen);
     XScreenSaverSelectInput(display, root, ScreenSaverNotifyMask);
 
-    /* Tell X to make the screen saver window 1 pixel by 1 pixel and off
-       the visible area, since we'll be creating our own.  I suspect jwz
-       is just blowing smoke. */
+    /* Tell X to show its provided window off the screen.  We make our own. */
     {
       XSetWindowAttributes attr;