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authorAndrew Bartlett <abartlet@samba.org>2010-03-22 16:03:33 +1100
committerAndrew Bartlett <abartlet@samba.org>2010-03-22 20:24:41 +1100
commitfe3e1af901c970f738bee92baac5d7d4f5736e17 (patch)
tree88666ac36e3d7041b24592600f361c412aaa5c3f
parentd0b54476fc9f855d1e482597538a7ec60e04f331 (diff)
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s4:dsdb Rework schema loading and add schema reloading
This commit reworks Samba4's schema loading code to detect when it needs to reload the schema. This is done by watching the @REPLCHANGED special DN. The reload happens by means of a callback, which is only set when the schema is loaded from the ldb - not when loaded from an LDIF file or DRS. We also rework the global schema handling - instead of storing the pointer to the global schema in each ldb, we store a flag indicating that the global schema should be returned at run time. This makes it much easier to switch to a new global schema. Andrew Bartlett
-rw-r--r--source4/dsdb/samdb/ldb_modules/schema_load.c231
-rw-r--r--source4/dsdb/schema/schema_set.c80
-rw-r--r--source4/lib/ldb_wrap.c5
3 files changed, 185 insertions, 131 deletions
diff --git a/source4/dsdb/samdb/ldb_modules/schema_load.c b/source4/dsdb/samdb/ldb_modules/schema_load.c
index 5ea70fbe3e..5dd8fb78c9 100644
--- a/source4/dsdb/samdb/ldb_modules/schema_load.c
+++ b/source4/dsdb/samdb/ldb_modules/schema_load.c
@@ -5,8 +5,8 @@
checkings, it also loads the dsdb_schema.
Copyright (C) Stefan Metzmacher <metze@samba.org> 2007
- Copyright (C) Andrew Bartlett <abartlet@samba.org> 2009
-
+ Copyright (C) Andrew Bartlett <abartlet@samba.org> 2009-2010
+
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; either version 3 of the License, or
@@ -31,19 +31,58 @@
#include "param/param.h"
#include "dsdb/samdb/ldb_modules/util.h"
+struct schema_load_private_data {
+ bool in_transaction;
+};
+
+static int dsdb_schema_from_db(struct ldb_module *module, struct ldb_dn *schema_dn, uint64_t current_usn,
+ struct dsdb_schema **schema);
+
+struct dsdb_schema *dsdb_schema_refresh(struct ldb_module *module, struct dsdb_schema *schema, bool is_global_schema)
+{
+ uint64_t current_usn;
+ int ret;
+ struct schema_load_private_data *private_data = talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data);
+ if (!private_data) {
+ /* We can't refresh until the init function has run */
+ return schema;
+ }
+
+ /* We don't allow a schema reload during a transaction - nobody else can modify our schema behind our backs */
+ if (private_data->in_transaction) {
+ return schema;
+ }
+
+ ret = dsdb_module_load_partition_usn(module, schema->base_dn, &current_usn, NULL);
+ if (ret == LDB_SUCCESS && current_usn != schema->loaded_usn) {
+ struct ldb_context *ldb = ldb_module_get_ctx(module);
+ struct dsdb_schema *new_schema;
+
+ ret = dsdb_schema_from_db(module, schema->base_dn, current_usn, &new_schema);
+ if (ret != LDB_SUCCESS) {
+ return schema;
+ }
+
+ if (is_global_schema) {
+ dsdb_make_schema_global(ldb, new_schema);
+ }
+ return new_schema;
+ }
+ return schema;
+}
+
+
/*
Given an LDB module (pointing at the schema DB), and the DN, set the populated schema
*/
-static int dsdb_schema_from_schema_dn(TALLOC_CTX *mem_ctx, struct ldb_module *module,
- struct smb_iconv_convenience *iconv_convenience,
- struct ldb_dn *schema_dn,
- struct dsdb_schema **schema)
+static int dsdb_schema_from_db(struct ldb_module *module, struct ldb_dn *schema_dn, uint64_t current_usn,
+ struct dsdb_schema **schema)
{
+ struct ldb_context *ldb = ldb_module_get_ctx(module);
TALLOC_CTX *tmp_ctx;
char *error_string;
int ret;
- struct ldb_context *ldb = ldb_module_get_ctx(module);
struct ldb_result *schema_res;
struct ldb_result *a_res;
struct ldb_result *c_res;
@@ -55,7 +94,7 @@ static int dsdb_schema_from_schema_dn(TALLOC_CTX *mem_ctx, struct ldb_module *mo
};
unsigned flags;
- tmp_ctx = talloc_new(mem_ctx);
+ tmp_ctx = talloc_new(module);
if (!tmp_ctx) {
ldb_oom(ldb);
return LDB_ERR_OPERATIONS_ERROR;
@@ -71,6 +110,9 @@ static int dsdb_schema_from_schema_dn(TALLOC_CTX *mem_ctx, struct ldb_module *mo
ret = dsdb_module_search_dn(module, tmp_ctx, &schema_res,
schema_dn, schema_attrs, 0);
if (ret == LDB_ERR_NO_SUCH_OBJECT) {
+ ldb_reset_err_string(ldb);
+ ldb_debug(ldb, LDB_DEBUG_WARNING,
+ "schema_load_init: no schema head present: (skip schema loading)\n");
goto failed;
} else if (ret != LDB_SUCCESS) {
ldb_asprintf_errstring(ldb,
@@ -112,11 +154,31 @@ static int dsdb_schema_from_schema_dn(TALLOC_CTX *mem_ctx, struct ldb_module *mo
schema_res, a_res, c_res, schema, &error_string);
if (ret != LDB_SUCCESS) {
ldb_asprintf_errstring(ldb,
- "dsdb_schema load failed: %s",
- error_string);
+ "dsdb_schema load failed: %s",
+ error_string);
goto failed;
}
- talloc_steal(mem_ctx, *schema);
+
+ (*schema)->refresh_fn = dsdb_schema_refresh;
+ (*schema)->loaded_from_module = module;
+ (*schema)->loaded_usn = current_usn;
+
+ /* dsdb_set_schema() steal schema into the ldb_context */
+ ret = dsdb_set_schema(ldb, (*schema));
+
+ if (ret != LDB_SUCCESS) {
+ ldb_debug_set(ldb, LDB_DEBUG_FATAL,
+ "schema_load_init: dsdb_set_schema() failed: %d:%s: %s",
+ ret, ldb_strerror(ret), ldb_errstring(ldb));
+ talloc_free(tmp_ctx);
+ return ret;
+ }
+
+ /* Ensure this module won't go away before the callback */
+ if (talloc_reference(*schema, ldb) == NULL) {
+ ldb_oom(ldb);
+ ret = LDB_ERR_OPERATIONS_ERROR;
+ }
failed:
if (flags & LDB_FLG_ENABLE_TRACING) {
@@ -130,18 +192,30 @@ failed:
static int schema_load_init(struct ldb_module *module)
{
- struct ldb_context *ldb;
- TALLOC_CTX *mem_ctx;
- struct ldb_dn *schema_dn;
+ struct schema_load_private_data *private_data;
struct dsdb_schema *schema;
+ struct ldb_context *ldb = ldb_module_get_ctx(module);
int ret;
+ uint64_t current_usn;
+ struct ldb_dn *schema_dn;
+
+ private_data = talloc_zero(module, struct schema_load_private_data);
+ if (private_data == NULL) {
+ ldb_oom(ldb);
+ return LDB_ERR_OPERATIONS_ERROR;
+ }
+
+ ldb_module_set_private(module, private_data);
ret = ldb_next_init(module);
if (ret != LDB_SUCCESS) {
return ret;
}
- ldb = ldb_module_get_ctx(module);
+ if (dsdb_get_schema(ldb, NULL)) {
+ return LDB_SUCCESS;
+ }
+
schema_dn = samdb_schema_dn(ldb);
if (!schema_dn) {
ldb_reset_err_string(ldb);
@@ -150,54 +224,51 @@ static int schema_load_init(struct ldb_module *module)
return LDB_SUCCESS;
}
- if (dsdb_get_schema(ldb, NULL)) {
- return LDB_SUCCESS;
+ ret = dsdb_module_load_partition_usn(module, schema_dn, &current_usn, NULL);
+ if (ret != LDB_SUCCESS) {
+ ldb_asprintf_errstring(ldb,
+ "dsdb_load_partition_usn failed: %s",
+ ldb_errstring(ldb));
+ return ret;
}
- mem_ctx = talloc_new(module);
- if (!mem_ctx) {
- ldb_oom(ldb);
- return LDB_ERR_OPERATIONS_ERROR;
- }
+ return dsdb_schema_from_db(module, schema_dn, current_usn, &schema);
+}
+
+static int schema_load_start_transaction(struct ldb_module *module)
+{
+ struct schema_load_private_data *private_data =
+ talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data);
- ret = dsdb_schema_from_schema_dn(mem_ctx, module,
- lp_iconv_convenience(ldb_get_opaque(ldb, "loadparm")),
- schema_dn, &schema);
+ private_data->in_transaction = true;
- if (ret == LDB_ERR_NO_SUCH_OBJECT) {
- ldb_reset_err_string(ldb);
- ldb_debug(ldb, LDB_DEBUG_WARNING,
- "schema_load_init: no schema head present: (skip schema loading)\n");
- talloc_free(mem_ctx);
- return LDB_SUCCESS;
- }
+ return ldb_next_start_trans(module);
+}
- if (ret != LDB_SUCCESS) {
- talloc_free(mem_ctx);
- return ret;
- }
+static int schema_load_del_transaction(struct ldb_module *module)
+{
+ struct schema_load_private_data *private_data =
+ talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data);
- /* dsdb_set_schema() steal schema into the ldb_context */
- ret = dsdb_set_schema(ldb, schema);
- if (ret != LDB_SUCCESS) {
- ldb_debug_set(ldb, LDB_DEBUG_FATAL,
- "schema_load_init: dsdb_set_schema() failed: %d:%s: %s",
- ret, ldb_strerror(ret), ldb_errstring(ldb));
- talloc_free(mem_ctx);
- return ret;
- }
+ private_data->in_transaction = false;
+
+ return ldb_next_del_trans(module);
+}
+
+static int schema_load_prepare_commit(struct ldb_module *module)
+{
+ int ret;
+ struct schema_load_private_data *private_data =
+ talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data);
- talloc_free(mem_ctx);
- return LDB_SUCCESS;
+ ret = ldb_next_prepare_commit(module);
+ private_data->in_transaction = false;
+ return ret;
}
static int schema_load_extended(struct ldb_module *module, struct ldb_request *req)
{
struct ldb_context *ldb;
- struct ldb_dn *schema_dn;
- struct dsdb_schema *schema;
- int ret;
- TALLOC_CTX *mem_ctx;
ldb = ldb_module_get_ctx(module);
@@ -205,60 +276,7 @@ static int schema_load_extended(struct ldb_module *module, struct ldb_request *r
return ldb_next_request(module, req);
}
- /*
- * TODO:
- *
- * We should check "schemaInfo" if we really need to reload the schema!
- *
- * We should also for a new schema version at the start of each
- * "write" (add/modify/rename/delete) operation. And have tests
- * to prove that windows does the same.
- */
-
- schema_dn = samdb_schema_dn(ldb);
- if (!schema_dn) {
- ldb_reset_err_string(ldb);
- ldb_debug(ldb, LDB_DEBUG_WARNING,
- "schema_load_extended: no schema dn present: (skip schema loading)\n");
- return ldb_next_request(module, req);
- }
-
- mem_ctx = talloc_new(module);
- if (!mem_ctx) {
- ldb_oom(ldb);
- return LDB_ERR_OPERATIONS_ERROR;
- }
-
- ret = dsdb_schema_from_schema_dn(mem_ctx, module,
- lp_iconv_convenience(ldb_get_opaque(ldb, "loadparm")),
- schema_dn, &schema);
-
- if (ret == LDB_ERR_NO_SUCH_OBJECT) {
- ldb_reset_err_string(ldb);
- ldb_debug(ldb, LDB_DEBUG_WARNING,
- "schema_load_extended: no schema head present: (skip schema loading)\n");
- talloc_free(mem_ctx);
- return ldb_next_request(module, req);
- }
-
- if (ret != LDB_SUCCESS) {
- talloc_free(mem_ctx);
- return ldb_next_request(module, req);
- }
-
- /* Replace the old schema*/
- ret = dsdb_set_schema(ldb, schema);
- if (ret != LDB_SUCCESS) {
- ldb_debug_set(ldb, LDB_DEBUG_FATAL,
- "schema_load_extended: dsdb_set_schema() failed: %d:%s: %s",
- ret, ldb_strerror(ret), ldb_errstring(ldb));
- talloc_free(mem_ctx);
- return ret;
- }
-
- dsdb_make_schema_global(ldb);
-
- talloc_free(mem_ctx);
+ /* This is a no-op. We reload as soon as we can */
return ldb_module_done(req, NULL, NULL, LDB_SUCCESS);
}
@@ -267,4 +285,7 @@ _PUBLIC_ const struct ldb_module_ops ldb_schema_load_module_ops = {
.name = "schema_load",
.init_context = schema_load_init,
.extended = schema_load_extended,
+ .start_transaction = schema_load_start_transaction,
+ .prepare_commit = schema_load_prepare_commit,
+ .del_transaction = schema_load_del_transaction,
};
diff --git a/source4/dsdb/schema/schema_set.c b/source4/dsdb/schema/schema_set.c
index e8fe7c4c65..1c7d39aa53 100644
--- a/source4/dsdb/schema/schema_set.c
+++ b/source4/dsdb/schema/schema_set.c
@@ -357,6 +357,11 @@ int dsdb_set_schema(struct ldb_context *ldb, struct dsdb_schema *schema)
return ret;
}
+ ret = ldb_set_opaque(ldb, "dsdb_use_global_schema", NULL);
+ if (ret != LDB_SUCCESS) {
+ return ret;
+ }
+
/* Set the new attributes based on the new schema */
ret = dsdb_schema_set_attributes(ldb, schema, true);
if (ret != LDB_SUCCESS) {
@@ -385,17 +390,6 @@ int dsdb_reference_schema(struct ldb_context *ldb, struct dsdb_schema *schema,
return ret;
}
- /* Set the new attributes based on the new schema */
- ret = dsdb_schema_set_attributes(ldb, schema, write_attributes);
- if (ret != LDB_SUCCESS) {
- return ret;
- }
-
- /* Keep a reference to this schema, just incase the original copy is replaced */
- if (talloc_reference(ldb, schema) == NULL) {
- return LDB_ERR_OPERATIONS_ERROR;
- }
-
return LDB_SUCCESS;
}
@@ -404,11 +398,27 @@ int dsdb_reference_schema(struct ldb_context *ldb, struct dsdb_schema *schema,
*/
int dsdb_set_global_schema(struct ldb_context *ldb)
{
+ int ret;
+ void *use_global_schema = (void *)1;
if (!global_schema) {
return LDB_SUCCESS;
}
- return dsdb_reference_schema(ldb, global_schema, false /* Don't write attributes, it's expensive */);
+ ret = ldb_set_opaque(ldb, "dsdb_use_global_schema", use_global_schema);
+ if (ret != LDB_SUCCESS) {
+ return ret;
+ }
+
+ /* Set the new attributes based on the new schema */
+ ret = dsdb_schema_set_attributes(ldb, global_schema, false /* Don't write attributes, it's expensive */);
+ if (ret == LDB_SUCCESS) {
+ /* Keep a reference to this schema, just incase the original copy is replaced */
+ if (talloc_reference(ldb, global_schema) == NULL) {
+ return LDB_ERR_OPERATIONS_ERROR;
+ }
+ }
+
+ return ret;
}
/**
@@ -420,23 +430,41 @@ int dsdb_set_global_schema(struct ldb_context *ldb)
struct dsdb_schema *dsdb_get_schema(struct ldb_context *ldb, TALLOC_CTX *reference_ctx)
{
const void *p;
- struct dsdb_schema *schema;
+ struct dsdb_schema *schema_out;
+ struct dsdb_schema *schema_in;
+ bool use_global_schema;
/* see if we have a cached copy */
- p = ldb_get_opaque(ldb, "dsdb_schema");
- if (!p) {
- return NULL;
+ use_global_schema = (ldb_get_opaque(ldb, "dsdb_use_global_schema") != NULL);
+ if (use_global_schema) {
+ schema_in = global_schema;
+ } else {
+ p = ldb_get_opaque(ldb, "dsdb_schema");
+
+ schema_in = talloc_get_type(p, struct dsdb_schema);
+ if (!schema_in) {
+ return NULL;
+ }
}
- schema = talloc_get_type(p, struct dsdb_schema);
- if (!schema) {
- return NULL;
+ if (schema_in->refresh_fn && !schema_in->refresh_in_progress) {
+ schema_in->refresh_in_progress = true;
+ /* This may change schema, if it needs to reload it from disk */
+ schema_out = schema_in->refresh_fn(schema_in->loaded_from_module,
+ schema_in,
+ use_global_schema);
+ schema_in->refresh_in_progress = false;
+ if (schema_out != schema_in) {
+ talloc_unlink(schema_in, ldb);
+ }
+ } else {
+ schema_out = schema_in;
}
if (!reference_ctx) {
- return schema;
+ return schema_out;
} else {
- return talloc_reference(reference_ctx, schema);
+ return talloc_reference(reference_ctx, schema_out);
}
}
@@ -444,9 +472,8 @@ struct dsdb_schema *dsdb_get_schema(struct ldb_context *ldb, TALLOC_CTX *referen
* Make the schema found on this ldb the 'global' schema
*/
-void dsdb_make_schema_global(struct ldb_context *ldb)
+void dsdb_make_schema_global(struct ldb_context *ldb, struct dsdb_schema *schema)
{
- struct dsdb_schema *schema = dsdb_get_schema(ldb, NULL);
if (!schema) {
return;
}
@@ -455,11 +482,14 @@ void dsdb_make_schema_global(struct ldb_context *ldb)
talloc_unlink(talloc_autofree_context(), global_schema);
}
- /* we want the schema to be around permanently */
- talloc_reparent(talloc_parent(schema), talloc_autofree_context(), schema);
+ /* Wipe any reference to the exact schema - we will set 'use the global schema' below */
+ ldb_set_opaque(ldb, "dsdb_schema", NULL);
+ /* we want the schema to be around permanently */
+ talloc_reparent(ldb, talloc_autofree_context(), schema);
global_schema = schema;
+ /* This calls the talloc_reference() of the global schema back onto the ldb */
dsdb_set_global_schema(ldb);
}
diff --git a/source4/lib/ldb_wrap.c b/source4/lib/ldb_wrap.c
index d5178467b1..8bcfb58f61 100644
--- a/source4/lib/ldb_wrap.c
+++ b/source4/lib/ldb_wrap.c
@@ -250,7 +250,10 @@ struct ldb_context *ldb_wrap_connect(TALLOC_CTX *mem_ctx,
/* make the resulting schema global */
if (lp_ctx != NULL && strcmp(lp_sam_url(lp_ctx), url) == 0) {
- dsdb_make_schema_global(ldb);
+ struct dsdb_schema *schema = dsdb_get_schema(ldb, NULL);
+ if (schema) {
+ dsdb_make_schema_global(ldb, schema);
+ }
}
DEBUG(3,("ldb_wrap open of %s\n", url));