persist-state.h

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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 PERSIST_STATE_H_INCLUDED
#define PERSIST_STATE_H_INCLUDED
 
#include "syslog-ng.h"
 
typedef struct _PersistFileHeader
{
  union
  {
    struct
    {
      /* should contain SLP4, everything is Big-Endian */
 
      /* 64 bytes for file header */
      gchar magic[4];
      /* should be zero, any non-zero value is not supported and causes the state to be dropped */
      guint32 flags;
      /* number of name-value keys in the file */
      guint32 key_count;
      /* space reserved for additional information in the header */
      gchar __reserved1[52];
      /* initial key store where the first couple of NV keys are stored, sized to align the header to 4k boundary */
      gchar initial_key_store[4032];
    };
    gchar __padding[4096];
  };
} PersistFileHeader;
 
typedef guint32 PersistEntryHandle;
 
typedef struct
{
  void (*handler)(gpointer user_data);
  gpointer cookie;
} PersistStateErrorHandler;
 
typedef struct _PersistEntry
{
  PersistEntryHandle ofs;
} PersistEntry;
 
struct _PersistState
{
  gint version;
  gchar *committed_filename;
  gchar *temp_filename;
  gint fd;
  gint mapped_counter;
  GMutex mapped_lock;
  GCond mapped_release_cond;
  guint32 current_size;
  guint32 current_ofs;
  gpointer current_map;
  PersistFileHeader *header;
  PersistStateErrorHandler error_handler;
 
  /* keys being used */
  GHashTable *keys;
  PersistEntryHandle current_key_block;
  gint current_key_ofs;
  gint current_key_size;
};
 
typedef struct _PersistState PersistState;
 
gpointer persist_state_map_entry(PersistState *self, PersistEntryHandle handle);
void persist_state_unmap_entry(PersistState *self, PersistEntryHandle handle);
 
PersistEntryHandle persist_state_alloc_entry(PersistState *self, const gchar *persist_name, gsize alloc_size);
PersistEntryHandle persist_state_lookup_entry(PersistState *self, const gchar *persist_name, gsize *size,
                                              guint8 *version);
gboolean persist_state_entry_exists(PersistState *self, const gchar *persist_name);
gboolean persist_state_remove_entry(PersistState *self, const gchar *persist_name);
 
gchar *persist_state_lookup_string(PersistState *self, const gchar *key, gsize *length, guint8 *version);
gboolean persist_state_rename_entry(PersistState *self, const gchar *old_key, const gchar *new_key);
gboolean persist_state_copy_entry(PersistState *self, const gchar *old_key, const gchar *new_key);
gboolean persist_state_move_entry(PersistState *self, const gchar *old_key, const gchar *new_key);
void persist_state_alloc_string(PersistState *self, const gchar *persist_name, const gchar *value, gssize len);
 
void persist_state_free_entry(PersistEntryHandle handle);
 
typedef void (*PersistStateForeachFunc)(gchar *name, gint entry_size, gpointer entry, gpointer userdata);
void persist_state_foreach_entry(PersistState *self, PersistStateForeachFunc func, gpointer userdata);
 
gboolean persist_state_start(PersistState *self);
gboolean persist_state_start_edit(PersistState *self);
gboolean persist_state_start_dump(PersistState *self);
 
const gchar *persist_state_get_filename(PersistState *self);
 
gboolean persist_state_commit(PersistState *self);
void persist_state_cancel(PersistState *self);
 
PersistState *persist_state_new(const gchar *filename);
void persist_state_free(PersistState *self);
 
void persist_state_set_global_error_handler(PersistState *self, void (*handler)(gpointer user_data),
                                            gpointer user_data);
 
#endif