Backport from 6.0-codebase.

WL#3771
  "Audit Plugin Interface"
  Implement new plug-in type - AUDIT
  New plug-in: audit_null
    simply increments counter for how many times it was called.

include/Makefile.am:
  wl3771
    add new headers to distribution
include/mysql/plugin.h:
  wl3771
    define new AUDIT plugin type
    Split out fulltext plugin type into its own header
include/mysql/plugin.h.pp:
  wl3771
    no real API change, just re-arranged some code
include/mysql/plugin_audit.h:
  wl3771
    pluggable audit interface
include/mysql/plugin_ftparser.h:
  wl3771
    Split out fulltext plugin type into its own header
libmysqld/CMakeLists.txt:
  wl3771
    add sql_audit.cc to build
libmysqld/Makefile.am:
  wl3771
    add sql_audit.cc to build
plugin/audit_null:
  wl3771
    an example plugin for testing pluggable audit interface
plugin/audit_null/Makefile.am:
  wl3771
    an example plugin for testing pluggable audit interface
plugin/audit_null/audit_null.c:
  wl3771
    an example plugin for testing pluggable audit interface
plugin/audit_null/plug.in:
  wl3771
    an example plugin for testing pluggable audit interface
sql/CMakeLists.txt:
  wl3771
    add sql_audit.cc to build
sql/Makefile.am:
  wl3771
    add sql_audit.cc to build
sql/event_queue.cc:
  wl3771
    release audit resources before waiting
sql/log.cc:
  wl3771
    add general audit call for log
sql/mysqld.cc:
  wl3771
    add audit initialize/finalize
    add general audit call for error
sql/sql_audit.cc:
  wl3771
    pluggable audit interface implementation
sql/sql_audit.h:
  wl3771
    pluggable audit interface implementation
sql/sql_class.cc:
  wl3771
    add thd audit init/deinit calls
sql/sql_class.h:
  wl3771
    add required data structures for audit to THD
sql/sql_connect.cc:
  wl3771
    release audit resources before waiting
sql/sql_insert.cc:
  wl3771
    release audit plugins before waiting
sql/sql_parse.cc:
  wl3771
    add general audit call for results
sql/sql_plugin.cc:
  wl3771
    add declarations for audit plugin type

3 files changed, 166 insertions, 0 deletions

diff --git a/plugin/audit_null/Makefile.am b/plugin/audit_null/Makefile.am
new file mode 100644
index 00000000000..d57a72f8c18
--- /dev/null
+++ b/plugin/audit_null/Makefile.am
@@ -0,0 +1,32 @@
+# Copyright (C) 2007 MySQL AB
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+#Makefile.am example for a plugin
+
+pkgplugindir=		$(pkglibdir)/plugin
+
+AM_CPPFLAGS =		-I$(top_srcdir)/include
+
+EXTRA_LTLIBRARIES=	adt_null.la
+pkgplugin_LTLIBRARIES=	@plugin_audit_null_shared_target@
+adt_null_la_LDFLAGS=	-module -rpath $(pkgplugindir)
+adt_null_la_CPPFLAGS=	$(AM_CPPFLAGS) -DMYSQL_DYNAMIC_PLUGIN
+adt_null_la_SOURCES=	audit_null.c
+
+EXTRA_LIBRARIES=	libadtnull.a
+noinst_LIBRARIES=	@plugin_audit_null_static_target@
+libadtnull_a_SOURCES=	audit_null.c
+
+EXTRA_DIST=		plug.in
diff --git a/plugin/audit_null/audit_null.c b/plugin/audit_null/audit_null.c
new file mode 100644
index 00000000000..52a9df08cf4
--- /dev/null
+++ b/plugin/audit_null/audit_null.c
@@ -0,0 +1,130 @@
+/* Copyright (C) 2006-2007 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA */
+
+#include <stdio.h>
+#include <mysql/plugin.h>
+#include <mysql/plugin_audit.h>
+
+#if !defined(__attribute__) && (defined(__cplusplus) || !defined(__GNUC__)  || __GNUC__ == 2 && __GNUC_MINOR__ < 8)
+#define __attribute__(A)
+#endif
+
+static volatile int number_of_calls; /* for SHOW STATUS, see below */
+
+
+/*
+  Initialize the plugin at server start or plugin installation.
+
+  SYNOPSIS
+    audit_null_plugin_init()
+
+  DESCRIPTION
+    Does nothing.
+
+  RETURN VALUE
+    0                    success
+    1                    failure (cannot happen)
+*/
+
+static int audit_null_plugin_init(void *arg __attribute__((unused)))
+{
+  number_of_calls= 0;
+  return(0);
+}
+
+
+/*
+  Terminate the plugin at server shutdown or plugin deinstallation.
+
+  SYNOPSIS
+    audit_null_plugin_deinit()
+    Does nothing.
+
+  RETURN VALUE
+    0                    success
+    1                    failure (cannot happen)
+
+*/
+
+static int audit_null_plugin_deinit(void *arg __attribute__((unused)))
+{
+  printf("audit_null was invoked %u times\n", number_of_calls);
+  return(0);
+}
+
+
+/*
+  Foo
+
+  SYNOPSIS
+    audit_null_notify()
+      thd                connection context
+
+  DESCRIPTION
+*/
+
+static void audit_null_notify(MYSQL_THD thd __attribute__((unused)),
+                              const struct mysql_event *event
+                              __attribute__((unused)))
+{
+  /* prone to races, oh well */
+  number_of_calls++;
+}
+
+
+/*
+  Plugin type-specific descriptor
+*/
+
+static struct st_mysql_audit audit_null_descriptor=
+{
+  MYSQL_AUDIT_INTERFACE_VERSION,    /* interface version      */
+  NULL,                             /* release_thd function   */
+  audit_null_notify,                /* notify function        */
+  { (unsigned long) -1 }            /* class mask             */
+};
+
+/*
+  Plugin status variables for SHOW STATUS
+*/
+
+static struct st_mysql_show_var simple_status[]=
+{
+  {"audit_null_called", (char *)&number_of_calls, SHOW_INT},
+  {0,0,0}
+};
+
+
+/*
+  Plugin library descriptor
+*/
+
+mysql_declare_plugin(audit_null)
+{
+  MYSQL_AUDIT_PLUGIN,         /* type                            */
+  &audit_null_descriptor,     /* descriptor                      */
+  "NULL_AUDIT",               /* name                            */
+  "MySQL AB",                 /* author                          */
+  "Simple NULL Audit",        /* description                     */
+  PLUGIN_LICENSE_GPL,
+  audit_null_plugin_init,     /* init function (when loaded)     */
+  audit_null_plugin_deinit,   /* deinit function (when unloaded) */
+  0x0001,                     /* version                         */
+  simple_status,              /* status variables                */
+  NULL,                       /* system variables                */
+  NULL
+}
+mysql_declare_plugin_end;
+
diff --git a/plugin/audit_null/plug.in b/plugin/audit_null/plug.in
new file mode 100644
index 00000000000..15b1a48b408
--- /dev/null
+++ b/plugin/audit_null/plug.in
@@ -0,0 +1,4 @@
+MYSQL_PLUGIN(audit_null,         [NULL Audit Plug-in],
+        [Simple black-hole Audit example plug-in])
+MYSQL_PLUGIN_DYNAMIC(audit_null, [adt_null.la])
+MYSQL_PLUGIN_STATIC(audit_null,  [libadtnull.a])