Make all combinations of G, P, J and zero-fill work with as little

effort as possible in most cases; ok djm@

diff --git a/lib/libc/stdlib/malloc.c b/lib/libc/stdlib/malloc.c
index 1cbe7fa..be80640 100644 (file)
--- a/lib/libc/stdlib/malloc.c
+++ b/lib/libc/stdlib/malloc.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: malloc.c,v 1.97 2008/08/23 07:49:38 djm Exp $ */
+/*     $OpenBSD: malloc.c,v 1.98 2008/08/25 17:56:17 otto Exp $        */
 /*
  * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
  *
@@ -1078,8 +1078,6 @@ omalloc(size_t sz, int zero_fill)
                        errno = ENOMEM;
                        return NULL;
                }
-               if (malloc_junk)
-                       memset(p + sz, SOME_JUNK, psz - sz);
                if (malloc_guard) {
                        if (mprotect((char *)p + psz - malloc_guard,
                            malloc_guard, PROT_NONE))
@@ -1087,11 +1085,28 @@ omalloc(size_t sz, int zero_fill)
                        malloc_guarded += malloc_guard;
                }
 
-               /* shift towards the end */
                if (malloc_move &&
-                   sz - malloc_guard < MALLOC_PAGESIZE - MALLOC_MINSIZE)
+                   sz - malloc_guard < MALLOC_PAGESIZE - MALLOC_MINSIZE) {
+                       /* fill whole allocation */
+                       if (malloc_junk)
+                               memset(p, SOME_JUNK, psz - malloc_guard);
+                       /* shift towards the end */
                        p = ((char *)p) + ((MALLOC_PAGESIZE - MALLOC_MINSIZE -
                            (sz - malloc_guard)) & ~(MALLOC_MINSIZE-1));
+                       /* fill zeros if needed and overwritten above */
+                       if (zero_fill && malloc_junk)
+                               memset(p, 0, sz - malloc_guard);
+               } else {
+                       if (malloc_junk) {
+                               if (zero_fill)
+                                       memset(p + sz - malloc_guard,
+                                           SOME_JUNK, psz - sz);
+                               else
+                                       memset(p,
+                                           SOME_JUNK, psz - malloc_guard);
+                       }
+               }
+
        } else {
                /* takes care of SOME_JUNK */
                p = malloc_bytes(&g_pool, sz);