[dwm] bug in grabkeys()

[Peter Hartlich]

Hi,

Changeset 1320:65c37b4be9cb introduces a bug in grabkeys() that causes
MODKEY presses to be ignored if numlock is enabled on my system.

The problem is that between initializing modifiers[] with numlockmask
and using it later, numlockmask is changed without updating modifiers[].

Maybe extract a function initmodmap(), to be called before grabkeys(),
from the modmap initializiation block? Right now grabbuttons(), which
uses numlockmask as well, subtly depends on grabkeys() having been
called beforehand; this might make it a little more explicit what's
going on.

I've attached a patch that works for me, hopefully someone who knows
more about that stuff can look over it.

Regards,
Peter

diff -r c4ecef7983b8 dwm.c
--- a/dwm.c     Mon Aug 18 19:28:34 2008 +0100
+++ b/dwm.c     Tue Aug 19 15:36:05 2008 +0200
@@ -158,6 +158,7 @@
 static void grabbuttons(Client *c, Bool focused);
 static void grabkeys(void);
 static void initfont(const char *fontstr);
+static void initmodmap(void);
 static Bool isprotodel(Client *c);
 static void keypress(XEvent *e);
 static void killclient(const Arg *arg);
@@ -753,16 +754,6 @@
        unsigned int i, j;
        unsigned int modifiers[] = { 0, LockMask, numlockmask, 
numlockmask|LockMask };
        KeyCode code;
-       XModifierKeymap *modmap;
-
-       /* init modifier map */
-       modmap = XGetModifierMapping(dpy);
-       for(i = 0; i < 8; i++)
-               for(j = 0; j < modmap->max_keypermod; j++) {
-                       if(modmap->modifiermap[i * modmap->max_keypermod + j] 
== XKeysymToKeycode(dpy, XK_Num_Lock))
-                               numlockmask = (1 << i);
-               }
-       XFreeModifiermap(modmap);
 
        XUngrabKey(dpy, AnyKey, AnyModifier, root);
        for(i = 0; i < LENGTH(keys); i++) {
@@ -811,6 +802,19 @@
                dc.font.descent = dc.font.xfont->descent;
        }
        dc.font.height = dc.font.ascent + dc.font.descent;
+}
+
+void
+initmodmap(void) {
+       unsigned int i, j;
+       XModifierKeymap *modmap;
+
+       modmap = XGetModifierMapping(dpy);
+       for(i = 0; i < 8; i++)
+               for(j = 0; j < modmap->max_keypermod; j++)
+                       if(modmap->modifiermap[i * modmap->max_keypermod + j] 
== XKeysymToKeycode(dpy, XK_Num_Lock))
+                               numlockmask = (1 << i);
+       XFreeModifiermap(modmap);
 }
 
 Bool
@@ -925,8 +929,10 @@
        XMappingEvent *ev = &e->xmapping;
 
        XRefreshKeyboardMapping(ev);
-       if(ev->request == MappingKeyboard)
+       if(ev->request == MappingKeyboard) {
+               initmodmap();
                grabkeys();
+       }
 }
 
 void
@@ -1373,8 +1379,7 @@
        XChangeWindowAttributes(dpy, root, CWEventMask|CWCursor, &wa);
        XSelectInput(dpy, root, wa.event_mask);
 
-
-       /* grab keys */
+       initmodmap();
        grabkeys();
 }