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Date: Sun, 18 Jan 2009 17:45:26 -0800
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Subject: PATCH: zend_mm_heap_overflow()
From: shire@tekrat.com (shire)


I'm releasing an extended PHP logging extension that we currently use at facebook with much success.  I currently use a small patch to determine if a memory overflow has occurred as there's currently no direct access into the allocator structures.  You can get more information on the project at http://tekrat.com/php/xlog/.

It would be useful if this patch (and perhaps more accessors into the memory allocator) where added.  Although I understand there should be some careful choices and limitations here, and this case is a pretty specific use case, but I thought I'd share it in case there are others who happen to find this useful as well or perhaps someone can propose a more general alternative.

Patches for different branches are here (I've pasted php53 below):

http://tekrat.com/downloads/bits/zend_mm_heap_overflow.php6.patch
http://tekrat.com/downloads/bits/zend_mm_heap_overflow.php53.patch
http://tekrat.com/downloads/bits/zend_mm_heap_overflow.php52.patch


diff --git a/ZendEngine2/zend_alloc.c b/ZendEngine2/zend_alloc.c
index 8853d06..b8884a0 100644
--- a/ZendEngine2/zend_alloc.c
+++ b/ZendEngine2/zend_alloc.c
@@ -2537,6 +2537,13 @@ ZEND_API void start_memory_manager(TSRMLS_D)
  #endif
  }

+/*** BEGIN Patch: zend_mm_heap_overflow ***/
+ZEND_API int zend_mm_heap_overflow(TSRMLS_D)
+{
+    return AG(mm_heap)->overflow;
+}
+/*** END Patch: zend_mm_heap_overflow ***/
+
  ZEND_API zend_mm_heap *zend_mm_set_heap(zend_mm_heap *new_heap TSRMLS_DC)
  {
   zend_mm_heap *old_heap;
diff --git a/ZendEngine2/zend_alloc.h b/ZendEngine2/zend_alloc.h
index d92df4b..3610931 100644
--- a/ZendEngine2/zend_alloc.h
+++ b/ZendEngine2/zend_alloc.h
@@ -231,6 +231,7 @@ struct _zend_mm_storage {
  };

  ZEND_API zend_mm_heap *zend_mm_startup_ex(const zend_mm_mem_handlers *handlers, size_t block_size, size_t reserve_size, int internal, void *params);
+ZEND_API int zend_mm_heap_overflow(TSRMLS_D); /* Patch: zend_mm_heap_overflow */
  ZEND_API zend_mm_heap *zend_mm_set_heap(zend_mm_heap *new_heap TSRMLS_DC);
  ZEND_API zend_mm_storage *zend_mm_get_storage(zend_mm_heap *heap);



-shire