ldb.c

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/* 
   ldb database library

   Copyright (C) Andrew Tridgell  2004
   Copyright (C) Simo Sorce  2005-2006

     ** NOTE! The following LGPL license applies to the ldb
     ** library. This does NOT imply that all of Samba is released
     ** under the LGPL
   
   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 3 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, see <http://www.gnu.org/licenses/>.
*/

/*
 *  Name: ldb
 *
 *  Component: ldb core API
 *
 *  Description: core API routines interfacing to ldb backends
 *
 *  Author: Andrew Tridgell
 */

#include "ldb_includes.h"

/* 
   initialise a ldb context
   The mem_ctx is optional
*/
struct ldb_context *ldb_init(void *mem_ctx)
{
	struct ldb_context *ldb = talloc_zero(mem_ctx, struct ldb_context);
	int ret;

	ret = ldb_setup_wellknown_attributes(ldb);
	if (ret != 0) {
		talloc_free(ldb);
		return NULL;
	}

	ldb_set_utf8_default(ldb);
	ldb_set_create_perms(ldb, 0666);
	ldb_set_modules_dir(ldb, LDB_MODULESDIR);

	return ldb;
}

static struct backends_list_entry {
	struct ldb_backend_ops *ops;
	struct backends_list_entry *prev, *next;
} *ldb_backends = NULL;

#ifndef STATIC_LIBLDB_BACKENDS 

#ifdef HAVE_LDB_LDAP
#define LDAP_INIT &ldb_ldap_backend_ops, \
				  &ldb_ldapi_backend_ops, \
				  &ldb_ldaps_backend_ops,
#else
#define LDAP_INIT
#endif

#ifdef HAVE_LDB_SQLITE3
#define SQLITE3_INIT &ldb_sqlite3_backend_ops,
#else
#define SQLITE3_INIT
#endif

#define STATIC_LIBLDB_BACKENDS \
	LDAP_INIT \
	SQLITE3_INIT \
	&ldb_tdb_backend_ops, 	\
	NULL
#endif

const static struct ldb_backend_ops *builtin_backends[] = {
	STATIC_LIBLDB_BACKENDS
};

static ldb_connect_fn ldb_find_backend(const char *url)
{
	struct backends_list_entry *backend;
	int i;

	for (i = 0; builtin_backends[i]; i++) {
		if (strncmp(builtin_backends[i]->name, url, strlen(builtin_backends[i]->name)) == 0)
			return builtin_backends[i]->connect_fn;
	}

	for (backend = ldb_backends; backend; backend = backend->next) {
		if (strncmp(backend->ops->name, url, strlen(backend->ops->name)) == 0) {
			return backend->ops->connect_fn;
		}
	}

	return NULL;
}

/*
 register a new ldb backend
*/
int ldb_register_backend(const char *url_prefix, ldb_connect_fn connectfn)
{
	struct ldb_backend_ops *backend = talloc(talloc_autofree_context(), struct ldb_backend_ops);
	struct backends_list_entry *entry = talloc(talloc_autofree_context(), struct backends_list_entry);

	if (ldb_find_backend(url_prefix)) {
		return LDB_SUCCESS;
	}

	/* Maybe check for duplicity here later on? */

	backend->name = talloc_strdup(backend, url_prefix);
	backend->connect_fn = connectfn;
	entry->ops = backend;
	DLIST_ADD(ldb_backends, entry);

	return LDB_SUCCESS;
}

/* 
   Return the ldb module form of a database. The URL can either be one of the following forms
   ldb://path
   ldapi://path

   flags is made up of LDB_FLG_*

   the options are passed uninterpreted to the backend, and are
   backend specific.

  This allows modules to get at only the backend module, for example where a module 
  may wish to direct certain requests at a particular backend.
*/
int ldb_connect_backend(struct ldb_context *ldb, const char *url, const char *options[],
			struct ldb_module **backend_module)
{
	int ret;
	char *backend;
	ldb_connect_fn fn;

	if (strchr(url, ':') != NULL) {
		backend = talloc_strndup(ldb, url, strchr(url, ':')-url);
	} else {
		/* Default to tdb */
		backend = talloc_strdup(ldb, "tdb");
	}

	fn = ldb_find_backend(backend);

	if (fn == NULL) {
		int (*init_fn) (void);

		init_fn = ldb_dso_load_symbol(ldb, backend,
					      "init_module");
		if (init_fn != NULL && init_fn() == 0) {
			fn = ldb_find_backend(backend);
		}
	}

	if (fn == NULL) {
		struct ldb_backend_ops *ops;
		char *symbol_name = talloc_asprintf(ldb, "ldb_%s_backend_ops", backend);
		if (symbol_name == NULL) {
			return LDB_ERR_OPERATIONS_ERROR;
		}
		ops = ldb_dso_load_symbol(ldb, backend, symbol_name);
		if (ops != NULL) {
			fn = ops->connect_fn;
		}
		talloc_free(symbol_name);
	}

	talloc_free(backend);

	if (fn == NULL) {
		ldb_debug(ldb, LDB_DEBUG_FATAL, "Unable to find backend for '%s'\n", url);
		return LDB_ERR_OTHER;
	}

	ret = fn(ldb, url, ldb->flags, options, backend_module);

	if (ret != LDB_SUCCESS) {
		ldb_debug(ldb, LDB_DEBUG_ERROR, "Failed to connect to '%s'\n", url);
		return ret;
	}
	return ret;
}

/*
  try to autodetect a basedn if none specified. This fixes one of my
  pet hates about ldapsearch, which is that you have to get a long,
  complex basedn right to make any use of it.
*/
void ldb_set_default_dns(struct ldb_context *ldb)
{
	TALLOC_CTX *tmp_ctx;
	int ret;
	struct ldb_result *res;
	struct ldb_dn *tmp_dn=NULL;
	static const char *attrs[] = {
		"rootDomainNamingContext",
		"configurationNamingContext",
		"schemaNamingContext",
		"defaultNamingContext",
		NULL
	};

	tmp_ctx = talloc_new(ldb);
	ret = ldb_search(ldb, ldb_dn_new(tmp_ctx, ldb, NULL), LDB_SCOPE_BASE, 
			 "(objectClass=*)", attrs, &res);
	if (ret == LDB_SUCCESS) {
		if (res->count == 1) {
			if (!ldb_get_opaque(ldb, "rootDomainNamingContext")) {
				tmp_dn = ldb_msg_find_attr_as_dn(ldb, ldb, res->msgs[0], "rootDomainNamingContext");
				ldb_set_opaque(ldb, "rootDomainNamingContext", tmp_dn);
			}

			if (!ldb_get_opaque(ldb, "configurationNamingContext")) {
				tmp_dn = ldb_msg_find_attr_as_dn(ldb, ldb, res->msgs[0], "configurationNamingContext");
				ldb_set_opaque(ldb, "configurationNamingContext", tmp_dn);
			}

			if (!ldb_get_opaque(ldb, "schemaNamingContext")) {
				tmp_dn = ldb_msg_find_attr_as_dn(ldb, ldb, res->msgs[0], "schemaNamingContext");
				ldb_set_opaque(ldb, "schemaNamingContext", tmp_dn);
			}

			if (!ldb_get_opaque(ldb, "defaultNamingContext")) {
				tmp_dn = ldb_msg_find_attr_as_dn(ldb, ldb, res->msgs[0], "defaultNamingContext");
				ldb_set_opaque(ldb, "defaultNamingContext", tmp_dn);
			}
		}
		talloc_free(res);
	}

	talloc_free(tmp_ctx);
}

struct ldb_dn *ldb_get_root_basedn(struct ldb_context *ldb)
{
	return talloc_get_type(ldb_get_opaque(ldb, "rootDomainNamingContext"), struct ldb_dn);
}

struct ldb_dn *ldb_get_config_basedn(struct ldb_context *ldb)
{
	return talloc_get_type(ldb_get_opaque(ldb, "configurationNamingContext"), struct ldb_dn);
}

struct ldb_dn *ldb_get_schema_basedn(struct ldb_context *ldb)
{
	return talloc_get_type(ldb_get_opaque(ldb, "schemaNamingContext"), struct ldb_dn);
}

struct ldb_dn *ldb_get_default_basedn(struct ldb_context *ldb)
{
	return talloc_get_type(ldb_get_opaque(ldb, "defaultNamingContext"), struct ldb_dn);
}

/* 
 connect to a database. The URL can either be one of the following forms
   ldb://path
   ldapi://path

   flags is made up of LDB_FLG_*

   the options are passed uninterpreted to the backend, and are
   backend specific
*/
int ldb_connect(struct ldb_context *ldb, const char *url, unsigned int flags, const char *options[])
{
	int ret;
	const char *url2;
	/* We seem to need to do this here, or else some utilities don't get ldb backends */

	ldb->flags = flags;

	url2 = talloc_strdup(ldb, url);
	if (!url2) {
		ldb_oom(ldb);
		return LDB_ERR_OPERATIONS_ERROR;
	}
	ret = ldb_set_opaque(ldb, "ldb_url", talloc_strdup(ldb, url2));
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	ret = ldb_connect_backend(ldb, url, options, &ldb->modules);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	if (ldb_load_modules(ldb, options) != LDB_SUCCESS) {
		ldb_debug(ldb, LDB_DEBUG_FATAL, "Unable to load modules for %s: %s\n",
			  url, ldb_errstring(ldb));
		return LDB_ERR_OTHER;
	}

	/* TODO: get timeout from options if available there */
	ldb->default_timeout = 300; /* set default to 5 minutes */

	/* set the default base dn */
	ldb_set_default_dns(ldb);

	return LDB_SUCCESS;
}

void ldb_set_errstring(struct ldb_context *ldb, const char *err_string)
{
	if (ldb->err_string) {
		talloc_free(ldb->err_string);
	}
	ldb->err_string = talloc_strdup(ldb, err_string);
}

void ldb_asprintf_errstring(struct ldb_context *ldb, const char *format, ...)
{
	va_list ap;
	char *old_string = NULL;

	if (ldb->err_string) {
		old_string = ldb->err_string;
	}

	va_start(ap, format);
	ldb->err_string = talloc_vasprintf(ldb, format, ap);
	va_end(ap);
	talloc_free(old_string);
}

void ldb_reset_err_string(struct ldb_context *ldb)
{
	if (ldb->err_string) {
		talloc_free(ldb->err_string);
		ldb->err_string = NULL;
	}
}

#define FIRST_OP(ldb, op) do { \
	module = ldb->modules;					\
	while (module && module->ops->op == NULL) module = module->next; \
	if (module == NULL) {						\
		ldb_asprintf_errstring(ldb, "unable to find module or backend to handle operation: " #op); \
		return LDB_ERR_OPERATIONS_ERROR;			\
	} \
} while (0)

/*
  start a transaction
*/
static int ldb_transaction_start_internal(struct ldb_context *ldb)
{
	struct ldb_module *module;
	int status;
	FIRST_OP(ldb, start_transaction);

	ldb_reset_err_string(ldb);

	status = module->ops->start_transaction(module);
	if (status != LDB_SUCCESS) {
		if (ldb->err_string == NULL) {
			/* no error string was setup by the backend */
			ldb_asprintf_errstring(ldb,
						"ldb transaction start: %s (%d)", 
						ldb_strerror(status), 
						status);
		}
	}
	return status;
}

/*
  commit a transaction
*/
static int ldb_transaction_commit_internal(struct ldb_context *ldb)
{
	struct ldb_module *module;
	int status;
	FIRST_OP(ldb, end_transaction);

	ldb_reset_err_string(ldb);

	status = module->ops->end_transaction(module);
	if (status != LDB_SUCCESS) {
		if (ldb->err_string == NULL) {
			/* no error string was setup by the backend */
			ldb_asprintf_errstring(ldb, 
						"ldb transaction commit: %s (%d)", 
						ldb_strerror(status), 
						status);
		}
	}
	return status;
}

/*
  cancel a transaction
*/
static int ldb_transaction_cancel_internal(struct ldb_context *ldb)
{
	struct ldb_module *module;
	int status;
	FIRST_OP(ldb, del_transaction);

	status = module->ops->del_transaction(module);
	if (status != LDB_SUCCESS) {
		if (ldb->err_string == NULL) {
			/* no error string was setup by the backend */
			ldb_asprintf_errstring(ldb, 
						"ldb transaction cancel: %s (%d)", 
						ldb_strerror(status), 
						status);
		}
	}
	return status;
}

int ldb_transaction_start(struct ldb_context *ldb)
{
	/* disable autotransactions */
	ldb->transaction_active++;

	return ldb_transaction_start_internal(ldb);
}

int ldb_transaction_commit(struct ldb_context *ldb)
{
	/* renable autotransactions (when we reach 0) */
	if (ldb->transaction_active > 0)
		ldb->transaction_active--;

	return ldb_transaction_commit_internal(ldb);
}

int ldb_transaction_cancel(struct ldb_context *ldb)
{
	/* renable autotransactions (when we reach 0) */
	if (ldb->transaction_active > 0)