Date: Wed, 4 Jul 2001 12:05:57 +0300 (IDT)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender: eliz AT is
To: djgpp-workers AT delorie DOT com, Charles Sandmann <sandmann AT clio DOT rice DOT edu>
Subject: Re: malloc() problem, DJDEV 203
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On Tue, 3 Jul 2001, I wrote:

> If that doesn't work, I think we can safely decline anything above 2GB, 
> which will avoid the signed/unsigned nuisance (inside malloc as well).

Does the following look right?


--- malloc.c~0	Wed Jul  4 09:55:04 2001
+++ malloc.c	Wed Jul  4 11:10:02 2001
@@ -132,6 +132,16 @@ malloc(size_t size)
 
   if (size<ALIGN) size = ALIGN;
   size = (size+(ALIGN-1))&~(ALIGN-1);
+
+  /* Refuse ridiculously large requests right away.  Anything beyond
+     2GB will be treated by sbrk as a negative request, i.e. as a
+     request to _decrease_ the heap size.  */
+  if (size > 0x7fffffff - 0x10000) /* sbrk rounds up to 64KB */
+  {
+    if (__libc_malloc_fail_hook)
+      __libc_malloc_fail_hook(size);
+    return 0;
+  }
 #if DEBUG
   printf("malloc(%u)\n", size);
 #endif