- libunbound documentation on how to avoid openssl race conditions.

git-svn-id: file:///svn/unbound/trunk@2926 be551aaa-1e26-0410-a405-d3ace91eadb9

doc/Changelog

@@ -1,6 +1,7 @@
 19 Jun 2013: Wouter
 	- streamtcp man page, contributed by Tomas Hozza.
 	- iana portlist updated.
+	- libunbound documentation on how to avoid openssl race conditions.
 
 25 Jun 2013: Wouter
 	- Squelch sendto-permission denied errors when the network is

doc/libunbound.3.in

@@ -171,6 +171,9 @@ by default. Use
 and
 .B ub_ctx_hosts
 to read them.
+Before you call this, use the openssl functions CRYPTO_set_id_callback and
+CRYPTO_set_locking_callback to set up asyncronous operation if you use
+lib openssl (the application calls these functions once for initialisation).
 .TP
 .B ub_ctx_delete
 Delete validation context and free associated resources.

libunbound/unbound.h

@@ -78,6 +78,10 @@
  *	... same as async for non-threaded
  *	... the callbacks are called in the thread that calls process(ctx)
  *
+ * Openssl needs to have locking in place, and the application must set
+ * it up, because a mere library cannot do this, use the calls
+ * CRYPTO_set_id_callback and CRYPTO_set_locking_callback.
+ *
  * If no threading is compiled in, the above async example uses fork(2) to
  * create a process to perform the work. The forked process exits when the 
  * calling process exits, or ctx_delete() is called.