X-Git-Url: http://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Ftalloc%2Ftalloc.h;h=54a702050e96d73409c8169e5ac58b11b359fc68;hb=99e576ac94fd86fcba188fb72ced9e8087ac1680;hp=8b0f8a38bc82d6782dbe29c2a56c4d3c1daaab63;hpb=16b7eb13fbcb1a04a71622e6310020baccc3c39c;p=ccan

diff --git a/ccan/talloc/talloc.h b/ccan/talloc/talloc.h
index 8b0f8a38..54a70205 100644
--- a/ccan/talloc/talloc.h
+++ b/ccan/talloc/talloc.h
@@ -26,8 +26,8 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdarg.h>
+#include <ccan/typesafe_cb/typesafe_cb.h>
 #include "config.h"
-#include "ccan/typesafe_cb/typesafe_cb.h"
 
 /*
   this uses a little trick to allow __LINE__ to be stringified
@@ -87,6 +87,30 @@
  */
 #define talloc(ctx, type) (type *)talloc_named_const(ctx, sizeof(type), #type)
 
+/**
+ * talloc_set - allocate dynamic memory for a type, into a pointer
+ * @ptr: pointer to the pointer to assign.
+ * @ctx: context to be parent of this allocation, or NULL.
+ *
+ * talloc_set() does a talloc, but also adds a destructor which will make the
+ * pointer invalid when it is freed.  This can find many use-after-free bugs.
+ *
+ * Note that the destructor is chained off a zero-length allocation, and so
+ * is not affected by talloc_set_destructor().
+ *
+ * Example:
+ *	unsigned int *a;
+ *	a = talloc(NULL, unsigned int);
+ *	talloc_set(&b, a, unsigned int);
+ *	talloc_free(a);
+ *	*b = 1; // This will crash!
+ *
+ * See Also:
+ *	talloc.
+ */
+#define talloc_set(pptr, ctx) \
+	_talloc_set((pptr), (ctx), sizeof(&**(pptr)), __location__)
+
 /**
  * talloc_free - free talloc'ed memory and its children
  * @ptr: the talloced pointer to free
@@ -119,7 +143,7 @@
  * See Also:
  *	talloc_set_destructor, talloc_unlink
  */
-int talloc_free(void *ptr);
+int talloc_free(const void *ptr);
 
 /**
  * talloc_set_destructor: set a destructor for when this pointer is freed
@@ -398,21 +422,6 @@ void talloc_report(const void *ptr, FILE *f);
  */
 #define talloc_ptrtype(ctx, ptr) (_TALLOC_TYPEOF(ptr))talloc_size(ctx, sizeof(*(ptr)))
 
-/**
- * talloc_free_children - free talloc'ed memory's children only
- * @ptr: the talloced pointer whose children we want to free
- *
- * talloc_free_children() walks along the list of all children of a talloc
- * context @ptr and talloc_free()s only the children, not the context itself.
- * Example:
- *	unsigned int *a, *b;
- *	a = talloc(NULL, unsigned int);
- *	b = talloc(a, unsigned int);
- *	// Frees b
- *	talloc_free_children(a);
- */
-void talloc_free_children(void *ptr);
-
 /**
  * talloc_new - create a new context
  * @ctx: the context to use as a parent.
@@ -929,33 +938,33 @@ size_t talloc_get_size(const void *ctx);
 void *talloc_find_parent_byname(const void *ctx, const char *name);
 
 /**
- * talloc_external_enable - set external allocators for some nodes
- * @alloc: the malloc() equivalent
- * @free: the free() equivalent
+ * talloc_add_external - create an externally allocated node
+ * @ctx: the parent
  * @realloc: the realloc() equivalent
+ * @lock: the call to lock before manipulation of external nodes
+ * @unlock: the call to unlock after manipulation of external nodes
  *
- * talloc_mark_external() can be used to mark nodes whose children should
- * use separate allocators.  Currently the set of allocators is global, not
- * per-node, and is set with this function.
+ * talloc_add_external() creates a node which uses a separate allocator.  All
+ * children allocated from that node will also use that allocator.
  *
- * The parent pointers is the talloc pointer of the parent.
- */
-void talloc_external_enable(void *(*alloc)(void *parent, size_t size),
-			    void (*free)(void *ptr, void *parent),
-			    void *(*realloc)(void *ptr, void *parent, size_t));
-
-/**
- * talloc_mark_external - children of this note must use external allocators
- * @p: the talloc pointer
+ * Note: Currently there is only one external allocator, not per-node,
+ * and it is set with this function.
+ *
+ * @lock is handed a pointer which was previous returned from your realloc
+ * function; you should use that to figure out which lock to get if you have
+ * multiple external pools.
  *
- * This function indicates that all children (and children's children etc)
- * should use the allocators set up wth talloc_external_enable() rather than
- * normal malloc/free.
+ * The parent pointers in realloc is the talloc pointer of the parent, if any.
  */
-void talloc_mark_external(void *ptr);
+void *talloc_add_external(const void *ctx,
+			  void *(*realloc)(const void *parent,
+					   void *ptr, size_t),
+			  void (*lock)(const void *p),
+			  void (*unlock)(void));
 
 /* The following definitions come from talloc.c  */
 void *_talloc(const void *context, size_t size);
+void _talloc_set(void *ptr, const void *ctx, size_t size, const char *name);
 void _talloc_set_destructor(const void *ptr, int (*destructor)(void *));
 size_t talloc_reference_count(const void *ptr);
 void *_talloc_reference(const void *context, const void *ptr);