[SCM] Samba Shared Repository - branch master updated

[Volker Lendecke]

The branch, master has been updated
       via  e325a5b talloc: Add a warning about talloc_autofree_context() and dlclose()
      from  e90c707 s3-waf: convert READLINE into a subsystem.

http://gitweb.samba.org/?p=samba.git;a=shortlog;h=master


- Log -----------------------------------------------------------------
commit e325a5b67453fd8cfe06d3d0d6c7c5ab7e4ad772
Author: Volker Lendecke <vl at samba.org>
Date:   Fri Sep 24 19:20:06 2010 +0200

    talloc: Add a warning about talloc_autofree_context() and dlclose()

-----------------------------------------------------------------------

Summary of changes:
 lib/talloc/talloc.h         |    9 +++++++++
 lib/talloc/talloc_guide.txt |   13 +++++++++++++
 2 files changed, 22 insertions(+), 0 deletions(-)


Changeset truncated at 500 lines:

diff --git a/lib/talloc/talloc.h b/lib/talloc/talloc.h
index 187d7e7..8b9ade2 100644
--- a/lib/talloc/talloc.h
+++ b/lib/talloc/talloc.h
@@ -972,6 +972,15 @@ int talloc_unlink(const void *context, void *ptr);
  * which will be automatically freed on program exit. This can be used
  * to reduce the noise in memory leak reports.
  *
+ * Never use this in code that might be used in objects loaded with
+ * dlopen and unloaded with dlclose. talloc_autofree_context()
+ * internally uses atexit(3). Some platforms like modern Linux handles
+ * this fine, but for example FreeBSD does not deal well with dlopen()
+ * and atexit() used simultaneously: dlclose() does not clean up the
+ * list of atexit-handlers, so when the program exits the code that
+ * was registered from within talloc_autofree_context() is gone, the
+ * program crashes at exit.
+ *
  * @return              A talloc context, NULL on error.
  */
 void *talloc_autofree_context(void);
diff --git a/lib/talloc/talloc_guide.txt b/lib/talloc/talloc_guide.txt
index a79fd03..f29b1d6 100644
--- a/lib/talloc/talloc_guide.txt
+++ b/lib/talloc/talloc_guide.txt
@@ -74,6 +74,19 @@ without proper synchronization ;
 shouldn't be used by several threads simultaneously without  
 synchronization.
 
+talloc and shared objects
+-------------------------
+
+talloc can be used in shared objects. Special care needs to be taken
+to never use talloc_autofree_context() in code that might be loaded
+with dlopen() and unloaded with dlclose(), as talloc_autofree_context()
+internally uses atexit(3). Some platforms like modern Linux handles
+this fine, but for example FreeBSD does not deal well with dlopen()
+and atexit() used simultaneously: dlclose() does not clean up the list
+of atexit-handlers, so when the program exits the code that was
+registered from within talloc_autofree_context() is gone, the program
+crashes at exit.
+
 
 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 (type *)talloc(const void *context, type);


-- 
Samba Shared Repository