samba-mirror/lib/ntdb/man/ntdb.3.xml

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<refentry>
  <refmeta>
    <refentrytitle>ntdb</refentrytitle>
    <manvolnum>3</manvolnum>
    <refmiscinfo class="source">Samba</refmiscinfo>
    <refmiscinfo class="manual">System Administration tools</refmiscinfo>
    <refmiscinfo class="version">4.1</refmiscinfo>
  </refmeta>
  <refnamediv>
    <refname>ntdb</refname>
<refpurpose>A not-so trivial keyword/data database system</refpurpose>
  </refnamediv>
  <refsynopsisdiv>
<synopsis>#include &lt;ntdb.h&gt;</synopsis>
  </refsynopsisdiv>
  <refsect1><title>DESCRIPTION</title>
    <para>
      If you have previously used the tdb library from Samba, much of
      this will seem familiar, but there are some API changes which a
      compiler will warn you about if you simply replace 'tdb' with
      'ntdb' in your code!  The on-disk format for ntdb is
      incompatible with tdb.
    </para>
    <para>
      tdb's API was based on gdbm, and ntdb continues this tradition,
      with enhancements.  A differences guide is available in the text
      file <filename>lib/ntdb/doc/TDB_porting.txt</filename> in the
      SAMBA source tree.
    </para>
  </refsect1>
  <refsect1><title>NTDB API OVERVIEW</title>
    <para>
      The complete API is documented in the ntdb.h header, which is
      kept up-to-date and recommended reading.
    </para>
    <para>
      Normal usage is to call ntdb_open() to create or open an ntdb
      file.  ntdb_store() is used to add records, ntdb_fetch() is used
      to fetch them.  Traversals are supported via callback
      (ntdb_traverse()) or iteration (ntdb_firstkey() and
      ntdb_nextkey()).  Transactions are supported for batching
      updates or reads atomically, using ntdb_transaction_start() and
      ntdb_transaction_commit().
    </para>
    <refsect2><title>Use With Talloc</title>
      <para>
	ntdb_open() takes an optional linked list of attributes:
	in particular you can specify an alternate allocator (such as
	talloc):
      </para>
      <programlisting>
#include &lt;talloc.h&gt;
#include &lt;ntdb.h&gt;

static void *my_alloc(const void *owner, size_t len, void *priv)
{
    return talloc_size(owner, len);
}

static void *my_expand(void *old, size_t newlen, void *priv)
{
    return talloc_realloc_size(NULL, old, newlen);
}

static void my_free(void *old, void *priv)
{
    talloc_free(old);
}

/* This opens an ntdb file as a talloc object with given parent. */
struct ntdb_context *ntdb_open_talloc(const void *parent,
                                      const char *filename)
{
     struct ntdb_context *ntdb;
     union ntdb_attribute alloc;

     alloc.base.attr = NTDB_ATTRIBUTE_ALLOCATOR;
     alloc.base.next = NULL;
     alloc.alloc.alloc = my_alloc;
     alloc.alloc.expand = my_expand;
     alloc.alloc.free = my_free;

     ntdb = ntdb_open(filename, NTDB_DEFAULT, O_RDWR|O_CREAT, 0600,
                      &amp;alloc);
     if (ntdb) {
         talloc_steal(parent, ntdb);
         talloc_set_name(ntdb, "%s", filename);
     }
     return ntdb;
}
</programlisting>
    </refsect2>
  </refsect1>
  <refsect1><title>SEE ALSO</title>
    <para>
      <ulink url="http://tdb.samba.org/"/>
    </para>
  </refsect1>

  <refsect1><title>AUTHOR</title>
    <para> The original tdb software was created by Andrew Tridgell, and
    is now developed by the
      Samba Team as an Open Source project similar to the way the
      Linux kernel is developed.  ntdb was derived from tdb, but mostly
      rewritten by Rusty Russell.
    </para>
  </refsect1>

  <refsect1><title>COPYRIGHT/LICENSE</title>
    <para>
      Copyright (C) Rusty Russell 2013, IBM Corporation
    </para>
    <para>
      This program 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 3 of the
      License, or (at your option) any later version.
    </para>
    <para>
      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.
    </para>
    <para>
      You should have received a copy of the GNU General Public License
      along with this program; if not, see http://www.gnu.org/licenses/.
    </para>
  </refsect1>
</refentry>