1 files changed, 23 insertions, 0 deletions
diff --git a/extras/mini-os/mm.c b/extras/mini-os/mm.c
index 11e249d421..f204fa66ec 100644
--- a/extras/mini-os/mm.c
+++ b/extras/mini-os/mm.c
@@ -360,6 +360,29 @@ void free_pages(void *pointer, int order)
    
 }
 
+#ifdef HAVE_LIBC
+void *sbrk(ptrdiff_t increment)
+{
+    unsigned long old_brk = brk;
+    unsigned long new_brk = old_brk + increment;
+
+    if (new_brk > heap_end) {
+	printk("Heap exhausted: %p + %lx = %p > %p\n", old_brk, increment, new_brk, heap_end);
+	return NULL;
+    }
+    
+    if (new_brk > heap_mapped) {
+        unsigned long n = (new_brk - heap_mapped + PAGE_SIZE - 1) / PAGE_SIZE;
+        do_map_zero(heap_mapped, n);
+        heap_mapped += n * PAGE_SIZE;
+    }
+
+    brk = new_brk;
+
+    return (void *) old_brk;
+}
+#endif
+
 
 
 void init_mm(void)