Simplified and renamed start_terminal() to start() which can start any

program. Skip the double fork() and explicitly ignore SIGCHLD to fend
off zombies.

Added support for mouse buttons on root window to optionally start a
program with start(). By default mouse button three starts mcmenu
which must be in PATH.

4 files changed, 87 insertions, 48 deletions

diff --git a/NEWS b/NEWS
index 46f0b1e..fd9e18e 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,14 @@
 
 User visible changes
 
+2011-11-22
+
+  * Now optionally starts programs when MODKEY + mouse buttons are
+    pressed on root window. See config.h for configuration and the
+    manual page for an example.
+
+    Also simplified starting programs.
+
 2011-11-17
 
   * In a ConfigureRequest we no longer obey window movements not
diff --git a/config.h b/config.h
index 35176a7..0291b11 100644
--- a/config.h
+++ b/config.h
@@ -33,6 +33,13 @@
 #define TERMINAL "urxvt"
 
 /*
+ * Start these programs when pressing MODKEY and mouse buttons on root window.
+ */
+#define MOUSE1 ""
+#define MOUSE2 ""
+#define MOUSE3 "mcmenu"
+
+/*
  * Default colour on border for focused windows. Can be set from
  * command line with "-f colour".
  */
diff --git a/mcwm.c b/mcwm.c
index 613d53e..0613c9f 100644
--- a/mcwm.c
+++ b/mcwm.c
@@ -326,7 +326,7 @@ static struct client *findclient(xcb_drawable_t win);
 static void focusnext(void);
 static void setunfocus(xcb_drawable_t win);
 static void setfocus(struct client *client);
-static int start_terminal(void);
+static int start(char *program);
 static void resizelim(struct client *client);
 static void moveresize(xcb_drawable_t win, uint16_t x, uint16_t y,
                        uint16_t width, uint16_t height);
@@ -2085,15 +2085,10 @@ void setfocus(struct client *client)
     focuswin = client;
 }
 
-/*
- * Start a program specified in conf.terminal.
- *
- * Returns 0 on success. 
- */
-int start_terminal(void)
+int start(char *program)
 {
     pid_t pid;
-
+    
     pid = fork();
     if (-1 == pid)
     {
@@ -2102,10 +2097,10 @@ int start_terminal(void)
     }
     else if (0 == pid)
     {
-        pid_t termpid;
-
-        /* In our first child. */
+        char *argv[2];
 
+        /* In the child. */
+        
         /*
          * Make this process a new process leader, otherwise the
          * terminal will die when the wm dies. Also, this makes any
@@ -2117,39 +2112,15 @@ int start_terminal(void)
             exit(1);
         }
         
-        /*
-         * Fork again for the terminal process. This way, the wm won't
-         * know anything about it.
-         */
-        termpid = fork();
-        if (-1 == termpid)
+        argv[0] = program;
+        argv[1] = NULL;
+
+        if (-1 == execvp(program, argv))
         {
-            perror("fork");
+            perror("execve");            
             exit(1);
         }
-        else if (0 == termpid)
-        {
-            char *argv[2];
-        
-            /* In the second child, now starting terminal. */
-        
-            argv[0] = conf.terminal;
-            argv[1] = NULL;
-
-            if (-1 == execvp(conf.terminal, argv))
-            {
-                perror("execve");            
-                exit(1);
-            }
-        } /* second child */
-
-        /* Exit our first child so the wm can pick up and continue. */
         exit(0);
-    } /* first child */
-    else
-    {
-        /* Wait for the first forked process to exit. */
-        waitpid(pid, NULL, 0);
     }
 
     return 0;
@@ -3010,7 +2981,7 @@ void handle_keypress(xcb_key_press_event_t *ev)
         switch (key)
         {
         case KEY_RET: /* return */
-            start_terminal();
+            start(conf.terminal);
             break;
 
         case KEY_F: /* f */
@@ -3486,6 +3457,32 @@ void events(void)
                    e->detail, (long)e->event, e->child, e->event_x,
                    e->event_y);
 
+            if (0 == e->child)
+            {
+                /* Mouse click on root window. Start programs? */
+
+                switch (e->detail)
+                {
+                case 1: /* Mouse button one. */
+                    start(MOUSE1);
+                    break;
+
+                case 2: /* Middle mouse button. */
+                    start(MOUSE2);                    
+                    break;
+
+                case 3: /* Mouse button three. */
+                    start(MOUSE3);
+                    break;
+
+                default:
+                    break;
+                } /* switch */
+
+                /* Break out of event switch. */
+                break;
+            }
+            
             /*
              * If we don't have any currently focused window, we can't
              * do anything. We don't want to do anything if the mouse
@@ -3498,11 +3495,6 @@ void events(void)
             }
 
             /*
-             * XXX if 0 == e->child, we're on the root window. Do
-             * something on the root when mouse buttons are pressed?
-             */            
-
-            /*
              * If middle button was pressed, raise window or lower
              * it if it was already on top.
              */
@@ -4004,6 +3996,13 @@ int main(int argc, char **argv)
 
     /* Install signal handlers. */
 
+    /* We ignore child exists. Don't create zombies. */
+    if (SIG_ERR == signal(SIGCHLD, SIG_IGN))
+    {
+        perror("mcwm: signal");
+        exit(1);
+    }
+
     if (SIG_ERR == signal(SIGINT, sigcatch))
     {
         perror("mcwm: signal");
@@ -4111,7 +4110,7 @@ int main(int argc, char **argv)
                     XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC, root, XCB_NONE,
                     1 /* left mouse button */,
                     MOUSEMODKEY);
-
+    
     xcb_grab_button(conn, 0, root, XCB_EVENT_MASK_BUTTON_PRESS
                     | XCB_EVENT_MASK_BUTTON_RELEASE,
                     XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC, root, XCB_NONE,
diff --git a/mcwm.man b/mcwm.man
index 5b234db..1f4ebf7 100644
--- a/mcwm.man
+++ b/mcwm.man
@@ -147,7 +147,10 @@ cursor. Of course, changing workspaces has nothing to do with the
 focused window.
 .PP
 If you don't like the default key bindings, border width, et cetera,
-look in the config.h file, change and recompile.
+look in the config.h file, change and recompile. In the config.h file
+you can also define mouse button actions on the root window. By
+default button 3 starts the command mcmenu. You can write your own
+mcmenu by using, for instance, 9menu or ratmenu.
 .PP
 .SH STARTING
 Typically the window manager is started from a script, either run by
@@ -179,5 +182,27 @@ exec urxvt
 .fi
 .in -4
 .sp
+.PP
+You may also want to define an mcmenu program for use with mcwm.
+Here's a complete example using the 9menu program:
+.sp
+.in +4
+.nf
+\&#! /bin/sh
+9menu -bg black -fg white \\
+ -popup \\
+ 'cpu:urxvt -e ssh cpu.example.org' \\
+ ':' \\
+ 'VGA On: xrandr --output VGA --on' \\
+ 'VGA Off: xrandr --output VGA --off' \\
+ 'VGA Above: xrandr --output VGA --auto --above LVDS' \\
+ ':' \\
+ 'HHKB: xkbcomp -I$HOME/conf/xkb $HOME/conf/xkb/hhkb.xkb $DISPLAY' \\
+ 'Thinkpad: xmodmap /home/mc/lib/xmodmap/thinkpad-x60.xmodmap' \\
+ ':' \\
+ 'close:'
+.fi
+.in -4
+.sp
 .SH AUTHOR
 Michael Cardell Widerkrantz <mc@hack.org>.