From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 25 Oct 2011 00:51:37 +0000 (+1030)
Subject: talloc: talloc_set_flag/talloc_unset_flag and TALLOC_FLAG_WARN_MAY_REFERENCE
X-Git-Url: http://git.samba.org/?p=rusty%2Fsamba.git;a=commitdiff_plain;h=refs%2Fheads%2Ftalloc-reference-check-wip

talloc: talloc_set_flag/talloc_unset_flag and TALLOC_FLAG_WARN_MAY_REFERENCE

Add new API for twiddling talloc features.  Make it fail on unknown features
for future compatibility.

The only feature is TALLOC_FLAG_WARN_MAY_REFERENCE, which gets serious with
warning about using talloc_may_reference().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---

diff --git a/lib/talloc/talloc.c b/lib/talloc/talloc.c
index 41684dfee18..5756a5e51f5 100644
--- a/lib/talloc/talloc.c
+++ b/lib/talloc/talloc.c
@@ -123,6 +123,7 @@
 */
 static void *null_context;
 static void *autofree_context;
+static unsigned int flags;
 
 /* used to enable fill of memory on free, which can be useful for
  * catching use after free errors when valgrind is too slow
@@ -285,6 +286,24 @@ _PUBLIC_ void talloc_set_log_fn(void (*log_fn)(const char *message))
 	talloc_log_fn = log_fn;
 }
 
+int talloc_set_flag(unsigned int flag)
+{
+	if (flag != TALLOC_FLAG_WARN_MAY_REFERENCE) {
+		return -1;
+	}
+	flags |= flag;
+	return 0;
+}
+
+int talloc_unset_flag(unsigned int flag)
+{
+	if (flag != TALLOC_FLAG_WARN_MAY_REFERENCE) {
+		return -1;
+	}
+	flags |= ~flag;
+	return 0;
+}
+
 static void talloc_log(const char *fmt, ...) PRINTF_ATTRIBUTE(1,2);
 static void talloc_log(const char *fmt, ...)
 {
@@ -711,6 +730,10 @@ _PUBLIC_ void *_talloc_reference_loc(const void *context, const void *ptr, const
 	if (unlikely(ptr == NULL)) return NULL;
 
 	tc = talloc_chunk_from_ptr(ptr);
+	if ((flags & TALLOC_FLAG_WARN_MAY_REFERENCE) && !(tc->flags & TALLOC_FLAG_MAY_REF)) {
+		talloc_log("talloc_reference on non-may_reference pointer at %s)", location);
+	}
+
 	handle = (struct talloc_reference_handle *)_talloc_named_const(context,
 						   sizeof(struct talloc_reference_handle),
 						   TALLOC_MAGIC_REFERENCE);
diff --git a/lib/talloc/talloc.h b/lib/talloc/talloc.h
index cedc8d50f02..956dd4cdd86 100644
--- a/lib/talloc/talloc.h
+++ b/lib/talloc/talloc.h
@@ -955,7 +955,7 @@ void *_talloc_reference_loc(const void *context, const void *ptr, const char *lo
  *	talloc_may_reference(a);
  * @endcode
  *
- * @see talloc_reference()
+ * @see talloc_reference(), talloc_set_flag()
  */
 void *talloc_may_reference(const void *ptr);
 
@@ -1711,6 +1711,26 @@ void talloc_enable_leak_report(void);
  */
 void talloc_enable_leak_report_full(void);
 
+#define TALLOC_FLAG_WARN_MAY_REFERENCE	0x1
+/**
+ * @brief Set a global flag which alters talloc's behavior.
+ *
+ * 0 is returned if the flag is known, -1 otherwise.
+ *
+ * Flag is one of the following:
+ * TALLOC_FLAG_WARN_MAY_REFERENCE:
+ *	Warn if talloc_reference() is called on a pointer without talloc_may_reference()
+ *	being called first.
+ */
+int talloc_set_flag(unsigned int flag);
+
+/**
+ * @brief Remove a global flag which alters talloc's behavior.
+ *
+ * 0 is returned if the flag is known, -1 otherwise.
+ */
+int talloc_unset_flag(unsigned int flag);
+
 /* @} ******************************************************************/
 
 void talloc_set_abort_fn(void (*abort_fn)(const char *reason));
diff --git a/lib/talloc/wscript b/lib/talloc/wscript
index 44e7f2b224d..f9acb7b3842 100644
--- a/lib/talloc/wscript
+++ b/lib/talloc/wscript
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 
 APPNAME = 'talloc'
-VERSION = '2.1.0'
+VERSION = '2.1.1'
 
 
 blddir = 'bin'