From: Nicholas Clark <nick@ccl4.org>
Date: Fri, 10 Feb 2006 14:25:33 +0000 (+0000)
Subject: With PERL_POISON defined, ensure freshly malloc()ed memory isn't zeros,
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=9a083ecf3183b31c0b60e9c5dac947cd40829810;p=p5sagit%2Fp5-mst-13.2.git

With PERL_POISON defined, ensure freshly malloc()ed memory isn't zeros,
and when PERL_TRACK_MEMPOOL is also defined scribble on any extension
added by realloc().

p4raw-id: //depot/perl@27151
---

diff --git a/util.c b/util.c
index c10dd29..61d4036 100644
--- a/util.c
+++ b/util.c
@@ -96,7 +96,13 @@ Perl_safesysmalloc(MEM_SIZE size)
 #ifdef PERL_TRACK_MEMPOOL
 	struct perl_memory_debug_header *const header
 	    = (struct perl_memory_debug_header *)ptr;
+#endif
+
+#ifdef PERL_POISON
+	Poison(((char *)ptr), size, char);
+#endif
 
+#ifdef PERL_TRACK_MEMPOOL
 	header->interpreter = aTHX;
 	/* Link us into the list.  */
 	header->prev = &PL_memory_debug_header;
@@ -180,6 +186,14 @@ Perl_safesysrealloc(Malloc_t where,MEM_SIZE size)
 	struct perl_memory_debug_header *const header
 	    = (struct perl_memory_debug_header *)ptr;
 
+#  ifdef PERL_POISON
+	if (header->size < size) {
+	    const MEM_SIZE fresh = size - header->size;
+	    char *start_of_fresh = ((char *)ptr) + size;
+	    Poison(start_of_fresh, fresh, char);
+	}
+#  endif
+
 	header->next->prev = header;
 	header->prev->next = header;