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/*
* Copyright (c) 2002-2012 Balabit
* Copyright (c) 1998-2012 Balázs Scheidler
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* As an additional exemption you are allowed to compile & link against the
* OpenSSL libraries as published by the OpenSSL project. See the file
* COPYING for details.
*
*/
#ifndef DRIVER_H_INCLUDED
#define DRIVER_H_INCLUDED
#include "syslog-ng.h"
#include "logpipe.h"
#include "logqueue.h"
#include "cfg.h"
#include "signal-slot-connector/signal-slot-connector.h"
/*
* Drivers overview
* ================
*
* In syslog-ng nomenclature a driver is either responsible for handling
* incoming messages (also known as source driver), or to send them out to
* another party (also known as the destination driver). Source drivers are
* created in "source" statements and destination drivers are similarly
* created in "destination" statements.
*
* Drivers are derived from LogPipes, in essence they use the same "queue"
* method to forward messages further down the processing pipeline.
*
* Driver plugins
* ==============
*
* It is possible to change the behaviour of a driver somewhat by adding
* "plugins" to drivers. These plugins basically get a chance to override
* LogDriver virtual methods, change their semantics and possibly rely on
* the original behaviour too. This way, functionalities that are present
* in all destination drivers can easily be shared, without having to recode
* the same stuff multiple times.
*
* Driver plugins are activated with the "attach" virtual method, which in
* turn may redirect any of the LogDriver virtual methods to themselves.
* They can even have a "user_data" pointer, so that they can locate their
* associated state.
*
* Multiple plugins can hook into the same method, by saving the original
* address & original user_data value.
*
*/
/* direction agnostic driver class: LogDriver, see specialized source & destination drivers below */
typedef struct _LogDriver LogDriver;
typedef struct _LogDriverPlugin LogDriverPlugin;
struct _LogDriverPlugin
{
SignalSlotConnector *signal_connector;
const gchar *name;
/* this function is called when the plugin is attached to a LogDriver
* instance. It should do whatever it is necessary to extend the
* functionality of the driver specified (e.g. hook into various
* methods).
*/
gboolean (*attach)(LogDriverPlugin *s, LogDriver *d);
void (*detach)(LogDriverPlugin *s, LogDriver *d);
void (*free_fn)(LogDriverPlugin *s);
};
static inline gboolean
log_driver_plugin_attach(LogDriverPlugin *self, LogDriver *d)
{
return self->attach(self, d);
}
static inline void
log_driver_plugin_detach(LogDriverPlugin *self, LogDriver *d)
{
if (self->detach)
self->detach(self, d);
}
static inline void
log_driver_plugin_free(LogDriverPlugin *self)
{
self->free_fn(self);
}
void log_driver_plugin_init_instance(LogDriverPlugin *self, const gchar *name);
void log_driver_plugin_free_method(LogDriverPlugin *self);
struct _LogDriver
{
LogPipe super;
gboolean optional;
gchar *group;
gchar *id;
GList *plugins;
StatsCounterItem *processed_group_messages;
};
gboolean log_driver_add_plugin(LogDriver *self, LogDriverPlugin *plugin);
void log_driver_append(LogDriver *self, LogDriver *next);
LogDriverPlugin *log_driver_lookup_plugin(LogDriver *self, const gchar *name);
#define log_driver_get_plugin(self, T, name) \
({ \
T *plugin = (T *) log_driver_lookup_plugin(self, name); \
g_assert(plugin != NULL); \
plugin; \
})
/* methods registered to the init/deinit virtual functions */
gboolean log_driver_init_method(LogPipe *s);
gboolean log_driver_deinit_method(LogPipe *s);
/* source driver class: LogSourceDriver */
typedef struct _LogSrcDriver LogSrcDriver;
struct _LogSrcDriver
{
LogDriver super;
gint group_len;
StatsCounterItem *received_global_messages;
};
gboolean log_src_driver_init_method(LogPipe *s);
gboolean log_src_driver_deinit_method(LogPipe *s);
void log_src_driver_queue_method(LogPipe *s, LogMessage *msg, const LogPathOptions *path_options);
void log_src_driver_init_instance(LogSrcDriver *self, GlobalConfig *cfg);
void log_src_driver_free(LogPipe *s);
/* destination driver class: LogDestDriver */
typedef struct _LogDestDriver LogDestDriver;
struct _LogDestDriver
{
LogDriver super;
LogQueue *(*acquire_queue)(LogDestDriver *s, const gchar *persist_name, gint stats_level,
StatsClusterKeyBuilder *driver_sck_builder,
StatsClusterKeyBuilder *queue_sck_builder);
void (*release_queue)(LogDestDriver *s, LogQueue *q);
/* queues managed by this LogDestDriver, all constructed queues come
* here and are automatically saved into cfg_persist & persist_state. */
GList *queues;
gint log_fifo_size;
gint throttle;
StatsCounterItem *queued_global_messages;
};
/* returns a reference */
static inline LogQueue *
log_dest_driver_acquire_queue(LogDestDriver *self, const gchar *persist_name, gint stats_level,
StatsClusterKeyBuilder *driver_sck_builder,
StatsClusterKeyBuilder *queue_sck_builder)
{
LogQueue *q;
q = self->acquire_queue(self, persist_name, stats_level, driver_sck_builder, queue_sck_builder);
if (q)
{
self->queues = g_list_prepend(self->queues, q);
}
return q;
}
/* consumes the reference in @q */
static inline void
log_dest_driver_release_queue(LogDestDriver *self, LogQueue *q)
{
if (q)
{
self->queues = g_list_remove(self->queues, q);
/* this drops the reference passed by the caller */
self->release_queue(self, q);
/* this drops the reference stored on the list */
log_queue_unref(q);
}
}
gboolean log_dest_driver_init_method(LogPipe *s);
gboolean log_dest_driver_deinit_method(LogPipe *s);
void log_dest_driver_queue_method(LogPipe *s, LogMessage *msg, const LogPathOptions *path_options);
void log_dest_driver_init_instance(LogDestDriver *self, GlobalConfig *cfg);
void log_dest_driver_free(LogPipe *s);
#endif
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