X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftalloc%2Ftalloc.c;h=ed958a8e5f25fdbeebf83f30b1ea8fef82d018bc;hp=ba998f5424b6570571a3bbe64b0bbdff82bba2ba;hb=d1cea3ebf96f61b5bbac1e74975700770e06add6;hpb=16b7eb13fbcb1a04a71622e6310020baccc3c39c

diff --git a/ccan/talloc/talloc.c b/ccan/talloc/talloc.c
index ba998f54..ed958a8e 100644
--- a/ccan/talloc/talloc.c
+++ b/ccan/talloc/talloc.c
@@ -43,7 +43,7 @@
 #define ALWAYS_REALLOC 0
 
 
-#define MAX_TALLOC_SIZE 0x10000000
+#define MAX_TALLOC_SIZE 0x7FFFFFFF
 #define TALLOC_MAGIC 0xe814ec70
 #define TALLOC_FLAG_FREE 0x01
 #define TALLOC_FLAG_LOOP 0x02
@@ -82,9 +82,9 @@
 static void *null_context;
 static pid_t *autofree_context;
 
-static void *(*tc_external_alloc)(void *parent, size_t size);
-static void (*tc_external_free)(void *ptr, void *parent);
-static void *(*tc_external_realloc)(void *ptr, void *parent, size_t size);
+static void *(*tc_external_realloc)(const void *parent, void *ptr, size_t size);
+static void (*tc_lock)(const void *ctx);
+static void (*tc_unlock)(void);
 
 struct talloc_reference_handle {
 	struct talloc_reference_handle *next, *prev;
@@ -149,6 +149,28 @@ do { \
 	if ((p) && ((p) != (list))) (p)->next = (p)->prev = NULL; \
 } while (0)
 
+static int locked;
+static inline void lock(const void *p)
+{
+	if (tc_lock && p) {
+		struct talloc_chunk *tc = talloc_chunk_from_ptr(p);
+
+		if (tc->flags & TALLOC_FLAG_EXT_ALLOC) {
+			if (locked)
+				TALLOC_ABORT("nested locking");
+			tc_lock(tc);
+			locked = 1;
+		}
+	}
+}
+
+static inline void unlock(void)
+{
+	if (locked) {
+		tc_unlock();
+		locked = 0;
+	}
+}
 
 /*
   return the parent chunk of a pointer
@@ -167,10 +189,23 @@ static inline struct talloc_chunk *talloc_parent_chunk(const void *ptr)
 	return tc->parent;
 }
 
+/* This version doesn't do locking, so you must already have it. */
+static void *talloc_parent_nolock(const void *ptr)
+{
+	struct talloc_chunk *tc;
+
+	tc = talloc_parent_chunk(ptr);
+	return tc ? TC_PTR_FROM_CHUNK(tc) : NULL;
+}
+
 void *talloc_parent(const void *ptr)
 {
-	struct talloc_chunk *tc = talloc_parent_chunk(ptr);
-	return tc? TC_PTR_FROM_CHUNK(tc) : NULL;
+	void *parent;
+
+	lock(ptr);
+	parent = talloc_parent_nolock(ptr);
+	unlock();
+	return parent;
 }
 
 /*
@@ -178,49 +213,32 @@ void *talloc_parent(const void *ptr)
 */
 const char *talloc_parent_name(const void *ptr)
 {
-	struct talloc_chunk *tc = talloc_parent_chunk(ptr);
+	struct talloc_chunk *tc;
+
+	lock(ptr);
+	tc = talloc_parent_chunk(ptr);
+	unlock();
+
 	return tc? tc->name : NULL;
 }
 
-/* 
-   Allocate a bit of memory as a child of an existing pointer
-*/
-static inline void *__talloc(const void *context, size_t size)
+static void *init_talloc(struct talloc_chunk *parent,
+			 struct talloc_chunk *tc,
+			 size_t size, int external)
 {
-	struct talloc_chunk *tc;
-	struct talloc_chunk *parent = NULL; /* Prevent spurious gcc warning */
-	unsigned flags = TALLOC_MAGIC;
-
-	if (unlikely(context == NULL)) {
-		context = null_context;
-	}
-
-	if (unlikely(size >= MAX_TALLOC_SIZE)) {
+	if (unlikely(tc == NULL))
 		return NULL;
-	}
-
-	if (likely(context)) {
-		parent = talloc_chunk_from_ptr(context);
-		if (unlikely(parent->flags & TALLOC_FLAG_EXT_ALLOC)) {
-			tc = tc_external_alloc(TC_PTR_FROM_CHUNK(parent),
-					       TC_HDR_SIZE+size);
-			flags |= TALLOC_FLAG_EXT_ALLOC;
-			goto alloc_done;
-		}
-	}
-
-	tc = (struct talloc_chunk *)malloc(TC_HDR_SIZE+size);
-alloc_done:
-	if (unlikely(tc == NULL)) return NULL;
 
 	tc->size = size;
-	tc->flags = flags;
+	tc->flags = TALLOC_MAGIC;
+	if (external)
+		tc->flags |= TALLOC_FLAG_EXT_ALLOC;
 	tc->destructor = NULL;
 	tc->child = NULL;
 	tc->name = NULL;
 	tc->refs = NULL;
 
-	if (likely(context)) {
+	if (likely(parent)) {
 		if (parent->child) {
 			parent->child->parent = NULL;
 			tc->next = parent->child;
@@ -238,6 +256,38 @@ alloc_done:
 	return TC_PTR_FROM_CHUNK(tc);
 }
 
+/* 
+   Allocate a bit of memory as a child of an existing pointer
+*/
+static inline void *__talloc(const void *context, size_t size)
+{
+	struct talloc_chunk *tc;
+	struct talloc_chunk *parent = NULL;
+	int external = 0;
+
+	if (unlikely(context == NULL)) {
+		context = null_context;
+	}
+
+	if (unlikely(size >= MAX_TALLOC_SIZE)) {
+		return NULL;
+	}
+
+	if (likely(context)) {
+		parent = talloc_chunk_from_ptr(context);
+		if (unlikely(parent->flags & TALLOC_FLAG_EXT_ALLOC)) {
+			tc = tc_external_realloc(context, NULL,
+						 TC_HDR_SIZE+size);
+			external = 1;
+			goto alloc_done;
+		}
+	}
+
+	tc = (struct talloc_chunk *)malloc(TC_HDR_SIZE+size);
+alloc_done:
+	return init_talloc(parent, tc, size, external);
+}
+
 /*
   setup a destructor to be called on free of a pointer
   the destructor should return 0 on success, or -1 on failure.
@@ -315,11 +365,15 @@ void *_talloc_reference(const void *context, const void *ptr)
 	struct talloc_reference_handle *handle;
 	if (unlikely(ptr == NULL)) return NULL;
 
+	lock(context);
 	tc = talloc_chunk_from_ptr(ptr);
 	handle = (struct talloc_reference_handle *)_talloc_named_const(context,
 						   sizeof(struct talloc_reference_handle),
 						   TALLOC_MAGIC_REFERENCE);
-	if (unlikely(handle == NULL)) return NULL;
+	if (unlikely(handle == NULL)) {
+		unlock();
+		return NULL;
+	}
 
 	/* note that we hang the destructor off the handle, not the
 	   main context as that allows the caller to still setup their
@@ -327,14 +381,95 @@ void *_talloc_reference(const void *context, const void *ptr)
 	talloc_set_destructor(handle, talloc_reference_destructor);
 	handle->ptr = discard_const_p(void, ptr);
 	_TLIST_ADD(tc->refs, handle);
+	unlock();
 	return handle->ptr;
 }
 
+/*
+  return 1 if ptr is a parent of context
+*/
+static int _talloc_is_parent(const void *context, const void *ptr)
+{
+	struct talloc_chunk *tc;
+
+	if (context == NULL) {
+		return 0;
+	}
+
+	tc = talloc_chunk_from_ptr(context);
+	while (tc) {
+		if (TC_PTR_FROM_CHUNK(tc) == ptr) {
+			return 1;
+		}
+		while (tc && tc->prev) tc = tc->prev;
+		if (tc) {
+			tc = tc->parent;
+		}
+	}
+	return 0;
+}
+
+/* 
+   move a lump of memory from one talloc context to another return the
+   ptr on success, or NULL if it could not be transferred.
+   passing NULL as ptr will always return NULL with no side effects.
+*/
+static void *__talloc_steal(const void *new_ctx, const void *ptr)
+{
+	struct talloc_chunk *tc, *new_tc;
+
+	if (unlikely(!ptr)) {
+		return NULL;
+	}
+
+	if (unlikely(new_ctx == NULL)) {
+		new_ctx = null_context;
+	}
+
+	tc = talloc_chunk_from_ptr(ptr);
+
+	if (unlikely(new_ctx == NULL)) {
+		if (tc->parent) {
+			_TLIST_REMOVE(tc->parent->child, tc);
+			if (tc->parent->child) {
+				tc->parent->child->parent = tc->parent;
+			}
+		} else {
+			if (tc->prev) tc->prev->next = tc->next;
+			if (tc->next) tc->next->prev = tc->prev;
+		}
+		
+		tc->parent = tc->next = tc->prev = NULL;
+		return discard_const_p(void, ptr);
+	}
+
+	new_tc = talloc_chunk_from_ptr(new_ctx);
+
+	if (unlikely(tc == new_tc || tc->parent == new_tc)) {
+		return discard_const_p(void, ptr);
+	}
+
+	if (tc->parent) {
+		_TLIST_REMOVE(tc->parent->child, tc);
+		if (tc->parent->child) {
+			tc->parent->child->parent = tc->parent;
+		}
+	} else {
+		if (tc->prev) tc->prev->next = tc->next;
+		if (tc->next) tc->next->prev = tc->prev;
+	}
+
+	tc->parent = new_tc;
+	if (new_tc->child) new_tc->child->parent = NULL;
+	_TLIST_ADD(new_tc->child, tc);
+
+	return discard_const_p(void, ptr);
+}
 
 /* 
    internal talloc_free call
 */
-static inline int _talloc_free(void *ptr)
+static inline int _talloc_free(const void *ptr)
 {
 	struct talloc_chunk *tc;
 	void *oldparent = NULL;
@@ -354,7 +489,7 @@ static inline int _talloc_free(void *ptr)
 		 * call another instance of talloc_free() on the current
 		 * pointer.
 		 */
-		is_child = talloc_is_parent(tc->refs, ptr);
+		is_child = _talloc_is_parent(tc->refs, ptr);
 		_talloc_free(tc->refs);
 		if (is_child) {
 			return _talloc_free(ptr);
@@ -373,7 +508,7 @@ static inline int _talloc_free(void *ptr)
 			return -1;
 		}
 		tc->destructor = (talloc_destructor_t)-1;
-		if (d(ptr) == -1) {
+		if (d(discard_const_p(void, ptr)) == -1) {
 			tc->destructor = d;
 			return -1;
 		}
@@ -381,7 +516,7 @@ static inline int _talloc_free(void *ptr)
 	}
 
 	if (unlikely(tc->flags & TALLOC_FLAG_EXT_ALLOC))
-		oldparent = talloc_parent(ptr);
+		oldparent = talloc_parent_nolock(ptr);
 
 	if (tc->parent) {
 		_TLIST_REMOVE(tc->parent->child, tc);
@@ -412,79 +547,30 @@ static inline int _talloc_free(void *ptr)
 				struct talloc_chunk *p = talloc_parent_chunk(ptr);
 				if (p) new_parent = TC_PTR_FROM_CHUNK(p);
 			}
-			talloc_steal(new_parent, child);
+			__talloc_steal(new_parent, child);
 		}
 	}
 
 	tc->flags |= TALLOC_FLAG_FREE;
 
 	if (unlikely(tc->flags & TALLOC_FLAG_EXT_ALLOC))
-		tc_external_free(tc, oldparent);
+		tc_external_realloc(oldparent, tc, 0);
 	else
 		free(tc);
 
 	return 0;
 }
 
-/* 
-   move a lump of memory from one talloc context to another return the
-   ptr on success, or NULL if it could not be transferred.
-   passing NULL as ptr will always return NULL with no side effects.
-*/
 void *_talloc_steal(const void *new_ctx, const void *ptr)
 {
-	struct talloc_chunk *tc, *new_tc;
-
-	if (unlikely(!ptr)) {
-		return NULL;
-	}
-
-	if (unlikely(new_ctx == NULL)) {
-		new_ctx = null_context;
-	}
-
-	tc = talloc_chunk_from_ptr(ptr);
+	void *p;
 
-	if (unlikely(new_ctx == NULL)) {
-		if (tc->parent) {
-			_TLIST_REMOVE(tc->parent->child, tc);
-			if (tc->parent->child) {
-				tc->parent->child->parent = tc->parent;
-			}
-		} else {
-			if (tc->prev) tc->prev->next = tc->next;
-			if (tc->next) tc->next->prev = tc->prev;
-		}
-		
-		tc->parent = tc->next = tc->prev = NULL;
-		return discard_const_p(void, ptr);
-	}
-
-	new_tc = talloc_chunk_from_ptr(new_ctx);
-
-	if (unlikely(tc == new_tc || tc->parent == new_tc)) {
-		return discard_const_p(void, ptr);
-	}
-
-	if (tc->parent) {
-		_TLIST_REMOVE(tc->parent->child, tc);
-		if (tc->parent->child) {
-			tc->parent->child->parent = tc->parent;
-		}
-	} else {
-		if (tc->prev) tc->prev->next = tc->next;
-		if (tc->next) tc->next->prev = tc->prev;
-	}
-
-	tc->parent = new_tc;
-	if (new_tc->child) new_tc->child->parent = NULL;
-	_TLIST_ADD(new_tc->child, tc);
-
-	return discard_const_p(void, ptr);
+	lock(new_ctx);
+	p = __talloc_steal(new_ctx, ptr);
+	unlock();
+	return p;
 }
 
-
-
 /*
   remove a secondary reference to a pointer. This undo's what
   talloc_reference() has done. The context and pointer arguments
@@ -531,16 +617,20 @@ int talloc_unlink(const void *context, void *ptr)
 		context = null_context;
 	}
 
+	lock(context);
 	if (talloc_unreference(context, ptr) == 0) {
+		unlock();
 		return 0;
 	}
 
 	if (context == NULL) {
 		if (talloc_parent_chunk(ptr) != NULL) {
+			unlock();
 			return -1;
 		}
 	} else {
 		if (talloc_chunk_from_ptr(context) != talloc_parent_chunk(ptr)) {
+			unlock();
 			return -1;
 		}
 	}
@@ -548,7 +638,9 @@ int talloc_unlink(const void *context, void *ptr)
 	tc_p = talloc_chunk_from_ptr(ptr);
 
 	if (tc_p->refs == NULL) {
-		return _talloc_free(ptr);
+		int ret = _talloc_free(ptr);
+		unlock();
+		return ret;
 	}
 
 	new_p = talloc_parent_chunk(tc_p->refs);
@@ -559,10 +651,12 @@ int talloc_unlink(const void *context, void *ptr)
 	}
 
 	if (talloc_unreference(new_parent, ptr) != 0) {
+		unlock();
 		return -1;
 	}
 
-	talloc_steal(new_parent, ptr);
+	__talloc_steal(new_parent, ptr);
+	unlock();
 
 	return 0;
 }
@@ -607,7 +701,9 @@ void *talloc_named(const void *context, size_t size, const char *fmt, ...)
 	void *ptr;
 	const char *name;
 
+	lock(context);
 	ptr = __talloc(context, size);
+	unlock();
 	if (unlikely(ptr == NULL)) return NULL;
 
 	va_start(ap, fmt);
@@ -615,7 +711,7 @@ void *talloc_named(const void *context, size_t size, const char *fmt, ...)
 	va_end(ap);
 
 	if (unlikely(name == NULL)) {
-		_talloc_free(ptr);
+		talloc_free(ptr);
 		return NULL;
 	}
 
@@ -678,50 +774,13 @@ void *talloc_init(const char *fmt, ...)
 	va_end(ap);
 
 	if (unlikely(name == NULL)) {
-		_talloc_free(ptr);
+		talloc_free(ptr);
 		return NULL;
 	}
 
 	return ptr;
 }
 
-/*
-  this is a replacement for the Samba3 talloc_destroy_pool functionality. It
-  should probably not be used in new code. It's in here to keep the talloc
-  code consistent across Samba 3 and 4.
-*/
-void talloc_free_children(void *ptr)
-{
-	struct talloc_chunk *tc;
-
-	if (unlikely(ptr == NULL)) {
-		return;
-	}
-
-	tc = talloc_chunk_from_ptr(ptr);
-
-	while (tc->child) {
-		/* we need to work out who will own an abandoned child
-		   if it cannot be freed. In priority order, the first
-		   choice is owner of any remaining reference to this
-		   pointer, the second choice is our parent, and the
-		   final choice is the null context. */
-		void *child = TC_PTR_FROM_CHUNK(tc->child);
-		const void *new_parent = null_context;
-		if (unlikely(tc->child->refs)) {
-			struct talloc_chunk *p = talloc_parent_chunk(tc->child->refs);
-			if (p) new_parent = TC_PTR_FROM_CHUNK(p);
-		}
-		if (unlikely(_talloc_free(child) == -1)) {
-			if (new_parent == null_context) {
-				struct talloc_chunk *p = talloc_parent_chunk(ptr);
-				if (p) new_parent = TC_PTR_FROM_CHUNK(p);
-			}
-			talloc_steal(new_parent, child);
-		}
-	}
-}
-
 /* 
    Allocate a bit of memory as a child of an existing pointer
 */
@@ -730,6 +789,35 @@ void *_talloc(const void *context, size_t size)
 	return __talloc(context, size);
 }
 
+static int talloc_destroy_pointer(void ***pptr)
+{
+	if ((uintptr_t)**pptr < getpagesize())
+		TALLOC_ABORT("Double free or invalid talloc_set?");
+	/* Invalidate pointer so it can't be used again. */
+	**pptr = (void *)1;
+	return 0;
+}
+
+void _talloc_set(void *ptr, const void *ctx, size_t size, const char *name)
+{
+	void ***child;
+	void **pptr = ptr;
+
+	*pptr = talloc_named_const(ctx, size, name);
+	if (unlikely(!*pptr))
+		return;
+
+	child = talloc(*pptr, void **);
+	if (unlikely(!child)) {
+		talloc_free(*pptr);
+		*pptr = NULL;
+		return;
+	}
+	*child = pptr;
+	talloc_set_name_const(child, "talloc_set destructor");
+	talloc_set_destructor(child, talloc_destroy_pointer);
+}
+
 /*
   externally callable talloc_set_name_const()
 */
@@ -745,7 +833,11 @@ void talloc_set_name_const(const void *ptr, const char *name)
 */
 void *talloc_named_const(const void *context, size_t size, const char *name)
 {
-	return _talloc_named_const(context, size, name);
+	void *p;
+	lock(context);
+	p = _talloc_named_const(context, size, name);
+	unlock();
+	return p;
 }
 
 /* 
@@ -756,10 +848,13 @@ void *talloc_named_const(const void *context, size_t size, const char *name)
    will not be freed if the ref_count is > 1 or the destructor (if
    any) returns non-zero
 */
-int talloc_free(void *ptr)
+int talloc_free(const void *ptr)
 {
 	int saved_errno = errno, ret;
-	ret = _talloc_free(ptr);
+
+	lock(ptr);
+	ret = _talloc_free(discard_const_p(void, ptr));
+	unlock();
 	if (ret == 0)
 		errno = saved_errno;
 	return ret;
@@ -778,7 +873,7 @@ void *_talloc_realloc(const void *context, void *ptr, size_t size, const char *n
 
 	/* size zero is equivalent to free() */
 	if (unlikely(size == 0)) {
-		_talloc_free(ptr);
+		talloc_free(ptr);
 		return NULL;
 	}
 
@@ -788,7 +883,7 @@ void *_talloc_realloc(const void *context, void *ptr, size_t size, const char *n
 
 	/* realloc(NULL) is equivalent to malloc() */
 	if (ptr == NULL) {
-		return _talloc_named_const(context, size, name);
+		return talloc_named_const(context, size, name);
 	}
 
 	tc = talloc_chunk_from_ptr(ptr);
@@ -798,11 +893,12 @@ void *_talloc_realloc(const void *context, void *ptr, size_t size, const char *n
 		return NULL;
 	}
 
+	lock(ptr);
 	if (unlikely(tc->flags & TALLOC_FLAG_EXT_ALLOC)) {
 		/* need to get parent before setting free flag. */
-		void *parent = talloc_parent(ptr);
+		void *parent = talloc_parent_nolock(ptr);
 		tc->flags |= TALLOC_FLAG_FREE;
-		new_ptr = tc_external_realloc(tc, parent, size + TC_HDR_SIZE);
+		new_ptr = tc_external_realloc(parent, tc, size + TC_HDR_SIZE);
 	} else {
 		/* by resetting magic we catch users of the old memory */
 		tc->flags |= TALLOC_FLAG_FREE;
@@ -820,6 +916,7 @@ void *_talloc_realloc(const void *context, void *ptr, size_t size, const char *n
 
 	if (unlikely(!new_ptr)) {	
 		tc->flags &= ~TALLOC_FLAG_FREE; 
+		unlock();
 		return NULL; 
 	}
 
@@ -841,6 +938,7 @@ void *_talloc_realloc(const void *context, void *ptr, size_t size, const char *n
 
 	tc->size = size;
 	_talloc_set_name_const(TC_PTR_FROM_CHUNK(tc), name);
+	unlock();
 
 	return TC_PTR_FROM_CHUNK(tc);
 }
@@ -860,18 +958,11 @@ void *_talloc_move(const void *new_ctx, const void *_pptr)
 /*
   return the total size of a talloc pool (subtree)
 */
-size_t talloc_total_size(const void *ptr)
+static size_t _talloc_total_size(const void *ptr)
 {
 	size_t total = 0;
 	struct talloc_chunk *c, *tc;
 
-	if (ptr == NULL) {
-		ptr = null_context;
-	}
-	if (ptr == NULL) {
-		return 0;
-	}
-
 	tc = talloc_chunk_from_ptr(ptr);
 
 	if (tc->flags & TALLOC_FLAG_LOOP) {
@@ -882,7 +973,7 @@ size_t talloc_total_size(const void *ptr)
 
 	total = tc->size;
 	for (c=tc->child;c;c=c->next) {
-		total += talloc_total_size(TC_PTR_FROM_CHUNK(c));
+		total += _talloc_total_size(TC_PTR_FROM_CHUNK(c));
 	}
 
 	tc->flags &= ~TALLOC_FLAG_LOOP;
@@ -890,10 +981,27 @@ size_t talloc_total_size(const void *ptr)
 	return total;
 }
 
+size_t talloc_total_size(const void *ptr)
+{
+	size_t total;
+
+	if (ptr == NULL) {
+		ptr = null_context;
+	}
+	if (ptr == NULL) {
+		return 0;
+	}
+
+	lock(ptr);
+	total = _talloc_total_size(ptr);
+	unlock();
+	return total;
+}	
+
 /*
   return the total number of blocks in a talloc pool (subtree)
 */
-size_t talloc_total_blocks(const void *ptr)
+static size_t _talloc_total_blocks(const void *ptr)
 {
 	size_t total = 0;
 	struct talloc_chunk *c, *tc = talloc_chunk_from_ptr(ptr);
@@ -906,7 +1014,7 @@ size_t talloc_total_blocks(const void *ptr)
 
 	total++;
 	for (c=tc->child;c;c=c->next) {
-		total += talloc_total_blocks(TC_PTR_FROM_CHUNK(c));
+		total += _talloc_total_blocks(TC_PTR_FROM_CHUNK(c));
 	}
 
 	tc->flags &= ~TALLOC_FLAG_LOOP;
@@ -914,10 +1022,18 @@ size_t talloc_total_blocks(const void *ptr)
 	return total;
 }
 
-/*
-  return the number of external references to a pointer
-*/
-size_t talloc_reference_count(const void *ptr)
+size_t talloc_total_blocks(const void *ptr)
+{
+	size_t total;
+
+	lock(ptr);
+	total = _talloc_total_blocks(ptr);
+	unlock();
+
+	return total;
+}
+
+static size_t _talloc_reference_count(const void *ptr)
 {
 	struct talloc_chunk *tc = talloc_chunk_from_ptr(ptr);
 	struct talloc_reference_handle *h;
@@ -929,10 +1045,23 @@ size_t talloc_reference_count(const void *ptr)
 	return ret;
 }
 
+/*
+  return the number of external references to a pointer
+*/
+size_t talloc_reference_count(const void *ptr)
+{
+	size_t ret;
+
+	lock(talloc_chunk_from_ptr(ptr));
+	ret = _talloc_reference_count(ptr);
+	unlock();
+	return ret;
+}
+
 /*
   report on memory usage by all children of a pointer, giving a full tree view
 */
-void talloc_report_depth_cb(const void *ptr, int depth, int max_depth,
+static void _talloc_report_depth_cb(const void *ptr, int depth, int max_depth,
 			    void (*callback)(const void *ptr,
 			  		     int depth, int max_depth,
 					     int is_ref,
@@ -941,11 +1070,6 @@ void talloc_report_depth_cb(const void *ptr, int depth, int max_depth,
 {
 	struct talloc_chunk *c, *tc;
 
-	if (ptr == NULL) {
-		ptr = null_context;
-	}
-	if (ptr == NULL) return;
-
 	tc = talloc_chunk_from_ptr(ptr);
 
 	if (tc->flags & TALLOC_FLAG_LOOP) {
@@ -964,12 +1088,29 @@ void talloc_report_depth_cb(const void *ptr, int depth, int max_depth,
 			struct talloc_reference_handle *h = (struct talloc_reference_handle *)TC_PTR_FROM_CHUNK(c);
 			callback(h->ptr, depth + 1, max_depth, 1, private_data);
 		} else {
-			talloc_report_depth_cb(TC_PTR_FROM_CHUNK(c), depth + 1, max_depth, callback, private_data);
+			_talloc_report_depth_cb(TC_PTR_FROM_CHUNK(c), depth + 1, max_depth, callback, private_data);
 		}
 	}
 	tc->flags &= ~TALLOC_FLAG_LOOP;
 }
 
+void talloc_report_depth_cb(const void *ptr, int depth, int max_depth,
+			    void (*callback)(const void *ptr,
+			  		     int depth, int max_depth,
+					     int is_ref,
+					     void *private_data),
+			    void *private_data)
+{
+	if (ptr == NULL) {
+		ptr = null_context;
+	}
+	if (ptr == NULL) return;
+
+	lock(ptr);
+	_talloc_report_depth_cb(ptr, depth, max_depth, callback, private_data);
+	unlock();
+}
+
 static void talloc_report_depth_FILE_helper(const void *ptr, int depth, int max_depth, int is_ref, void *_f)
 {
 	const char *name = talloc_get_name(ptr);
@@ -983,17 +1124,17 @@ static void talloc_report_depth_FILE_helper(const void *ptr, int depth, int max_
 	if (depth == 0) {
 		fprintf(f,"%stalloc report on '%s' (total %6lu bytes in %3lu blocks)\n", 
 			(max_depth < 0 ? "full " :""), name,
-			(unsigned long)talloc_total_size(ptr),
-			(unsigned long)talloc_total_blocks(ptr));
+			(unsigned long)_talloc_total_size(ptr),
+			(unsigned long)_talloc_total_blocks(ptr));
 		return;
 	}
 
 	fprintf(f, "%*s%-30s contains %6lu bytes in %3lu blocks (ref %d) %p\n", 
 		depth*4, "",
 		name,
-		(unsigned long)talloc_total_size(ptr),
-		(unsigned long)talloc_total_blocks(ptr),
-		(int)talloc_reference_count(ptr), ptr);
+		(unsigned long)_talloc_total_size(ptr),
+		(unsigned long)_talloc_total_blocks(ptr),
+		(int)_talloc_reference_count(ptr), ptr);
 
 #if 0
 	fprintf(f, "content: ");
@@ -1100,7 +1241,11 @@ void talloc_enable_leak_report_full(void)
 */
 void *_talloc_zero(const void *ctx, size_t size, const char *name)
 {
-	void *p = _talloc_named_const(ctx, size, name);
+	void *p;
+
+	lock(ctx);
+	p = _talloc_named_const(ctx, size, name);
+	unlock();
 
 	if (p) {
 		memset(p, '\0', size);
@@ -1114,7 +1259,11 @@ void *_talloc_zero(const void *ctx, size_t size, const char *name)
 */
 void *_talloc_memdup(const void *t, const void *p, size_t size, const char *name)
 {
-	void *newp = _talloc_named_const(t, size, name);
+	void *newp;
+
+	lock(t);
+	newp = _talloc_named_const(t, size, name);
+	unlock();
 
 	if (likely(newp)) {
 		memcpy(newp, p, size);
@@ -1175,7 +1324,9 @@ char *talloc_strndup(const void *t, const char *p, size_t n)
 
 	for (len=0; len<n && p[len]; len++) ;
 
+	lock(t);
 	ret = (char *)__talloc(t, len + 1);
+	unlock();
 	if (!ret) { return NULL; }
 	memcpy(ret, p, len);
 	ret[len] = 0;
@@ -1198,7 +1349,9 @@ char *talloc_vasprintf(const void *t, const char *fmt, va_list ap)
 		return NULL;
 	}
 
+	lock(t);
 	ret = (char *)__talloc(t, len+1);
+	unlock();
 	if (ret) {
 		va_copy(ap2, ap);
 		vsnprintf(ret, len+1, fmt, ap2);
@@ -1291,10 +1444,15 @@ char *talloc_asprintf_append(char *s, const char *fmt, ...)
 */
 void *_talloc_array(const void *ctx, size_t el_size, unsigned count, const char *name)
 {
+	void *p;
+
 	if (count >= MAX_TALLOC_SIZE/el_size) {
 		return NULL;
 	}
-	return _talloc_named_const(ctx, el_size * count, name);
+	lock(ctx);
+	p = _talloc_named_const(ctx, el_size * count, name);
+	unlock();
+	return p;
 }
 
 /*
@@ -1302,10 +1460,13 @@ void *_talloc_array(const void *ctx, size_t el_size, unsigned count, const char
 */
 void *_talloc_zero_array(const void *ctx, size_t el_size, unsigned count, const char *name)
 {
+	void *p;
+
 	if (count >= MAX_TALLOC_SIZE/el_size) {
 		return NULL;
 	}
-	return _talloc_zero(ctx, el_size * count, name);
+	p = _talloc_zero(ctx, el_size * count, name);
+	return p;
 }
 
 /*
@@ -1339,7 +1500,7 @@ static int talloc_autofree_destructor(void *ptr)
 static void talloc_autofree(void)
 {
 	if (autofree_context && *autofree_context == getpid())
-		_talloc_free(autofree_context);
+		talloc_free(autofree_context);
 }
 
 /*
@@ -1382,9 +1543,11 @@ void *talloc_find_parent_byname(const void *context, const char *name)
 		return NULL;
 	}
 
+	lock(context);
 	tc = talloc_chunk_from_ptr(context);
 	while (tc) {
 		if (tc->name && strcmp(tc->name, name) == 0) {
+			unlock();
 			return TC_PTR_FROM_CHUNK(tc);
 		}
 		while (tc && tc->prev) tc = tc->prev;
@@ -1392,6 +1555,7 @@ void *talloc_find_parent_byname(const void *context, const char *name)
 			tc = tc->parent;
 		}
 	}
+	unlock();
 	return NULL;
 }
 
@@ -1407,6 +1571,7 @@ void talloc_show_parents(const void *context, FILE *file)
 		return;
 	}
 
+	lock(context);
 	tc = talloc_chunk_from_ptr(context);
 	fprintf(file, "talloc parents of '%s'\n", talloc_get_name(context));
 	while (tc) {
@@ -1416,48 +1581,41 @@ void talloc_show_parents(const void *context, FILE *file)
 			tc = tc->parent;
 		}
 	}
+	unlock();
 	fflush(file);
 }
 
-/*
-  return 1 if ptr is a parent of context
-*/
 int talloc_is_parent(const void *context, const void *ptr)
 {
-	struct talloc_chunk *tc;
-
-	if (context == NULL) {
-		return 0;
-	}
-
-	tc = talloc_chunk_from_ptr(context);
-	while (tc) {
-		if (TC_PTR_FROM_CHUNK(tc) == ptr) return 1;
-		while (tc && tc->prev) tc = tc->prev;
-		if (tc) {
-			tc = tc->parent;
-		}
-	}
-	return 0;
+	int ret;
+	lock(context);
+	ret = _talloc_is_parent(context, ptr);
+	unlock();
+	return ret;
 }
 
-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))
+void *talloc_add_external(const void *ctx,
+			  void *(*realloc)(const void *, void *, size_t),
+			  void (*lock)(const void *p),
+			  void (*unlock)(void))
 {
-	tc_external_alloc = alloc;
-	tc_external_free = free;
+	struct talloc_chunk *tc, *parent;
+	void *p;
+
+	if (tc_external_realloc && tc_external_realloc != realloc)
+		TALLOC_ABORT("talloc_add_external realloc replaced");
 	tc_external_realloc = realloc;
-}
 
-void talloc_mark_external(void *context)
-{
-	struct talloc_chunk *tc;
+	if (unlikely(ctx == NULL)) {
+		ctx = null_context;
+		parent = NULL;
+	} else
+		parent = talloc_chunk_from_ptr(ctx);	
 
-	if (unlikely(context == NULL)) {
-		context = null_context;
-	}
+	tc = tc_external_realloc(ctx, NULL, TC_HDR_SIZE);
+	p = init_talloc(parent, tc, 0, 1);
+	tc_lock = lock;
+	tc_unlock = unlock;
 
-	tc = talloc_chunk_from_ptr(context);
-	tc->flags |= TALLOC_FLAG_EXT_ALLOC;
+	return p;
 }