[src/trunk]: src/sys/dev/wscons try not to crash when calling glyphcache_wipe...

[macallan <macallan%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/72c10291abe8
branches:  trunk
changeset: 792695:72c10291abe8
user:      macallan <macallan%NetBSD.org@localhost>
date:      Mon Jan 13 19:30:33 2014 +0000

description:
try not to crash when calling glyphcache_wipe() on an uninitialized cache
first step to fix PR 48492

diffstat:

 sys/dev/wscons/wsdisplay_glyphcache.c |  7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diffs (28 lines):

diff -r 20f834ecbe31 -r 72c10291abe8 sys/dev/wscons/wsdisplay_glyphcache.c
--- a/sys/dev/wscons/wsdisplay_glyphcache.c     Mon Jan 13 18:57:48 2014 +0000
+++ b/sys/dev/wscons/wsdisplay_glyphcache.c     Mon Jan 13 19:30:33 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: wsdisplay_glyphcache.c,v 1.5 2012/11/13 20:29:03 macallan Exp $        */
+/*     $NetBSD: wsdisplay_glyphcache.c,v 1.6 2014/01/13 19:30:33 macallan Exp $        */
 
 /*
  * Copyright (c) 2012 Michael Lorenz
@@ -67,6 +67,8 @@
        gc->gc_cellheight = cellheight;
        gc->gc_firstline = first;
        gc->gc_cellsperline = width / cellwidth;
+       gc->gc_buckets = NULL;
+       gc->gc_numbuckets = 0;
        if (lines < 0) lines = 0;
        cache_lines = lines / cellheight;
        gc->gc_numcells = cache_lines * gc->gc_cellsperline;
@@ -124,6 +126,9 @@
        gc_bucket *b;
        int i, j, idx;
 
+       if ((gc->gc_buckets == NULL) || (gc->gc_numbuckets < 1))
+               return;
+
        idx = gc->gc_buckets[0].gb_index;
 
        /* empty all the buckets */