From 718ed842ba0b56ec2310feb415e83ce15284868f Mon Sep 17 00:00:00 2001 From: Matthieu Patou Date: Tue, 22 May 2012 15:13:04 -0700 Subject: [PATCH] s4-dsdb: Check for key SCHEMA_SEQ_NUM in metadata.tdb updates If the value has changed then reload the schema, this means that now the schema is only reloaded on a periodical basis or if we have been asked explicitly to do it and not necesserly if the schema partition has changed. --- source4/dsdb/samdb/ldb_modules/schema_load.c | 186 ++++++++++++++++++- source4/dsdb/schema/schema.h | 9 +- 2 files changed, 192 insertions(+), 3 deletions(-) diff --git a/source4/dsdb/samdb/ldb_modules/schema_load.c b/source4/dsdb/samdb/ldb_modules/schema_load.c index 9ae99a44b29..0ba0180e95a 100644 --- a/source4/dsdb/samdb/ldb_modules/schema_load.c +++ b/source4/dsdb/samdb/ldb_modules/schema_load.c @@ -29,18 +29,133 @@ #include "librpc/gen_ndr/ndr_drsuapi.h" #include "librpc/gen_ndr/ndr_drsblobs.h" #include "param/param.h" +#include "lib/tdb_wrap/tdb_wrap.h" +#include "lib/tdb_compat/tdb_compat.h" #include "dsdb/samdb/ldb_modules/util.h" +#include "system/filesys.h" struct schema_load_private_data { bool in_transaction; + struct tdb_wrap *metadata; }; static int dsdb_schema_from_db(struct ldb_module *module, struct ldb_dn *schema_dn, uint64_t current_usn, struct dsdb_schema **schema); +/* + * Open sam.ldb.d/metadata.tdb. + */ +static int schema_metadata_open(struct ldb_module *module) +{ + struct schema_load_private_data *data = talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data); + struct ldb_context *ldb = ldb_module_get_ctx(module); + TALLOC_CTX *tmp_ctx; + struct loadparm_context *lp_ctx; + const char *sam_name; + char *filename; + int open_flags; + struct stat statbuf; + + if (!data) { + return ldb_module_error(module, LDB_ERR_OPERATIONS_ERROR, + "schema_load: metadata not initialized"); + } + data->metadata = NULL; + + tmp_ctx = talloc_new(NULL); + if (tmp_ctx == NULL) { + return ldb_module_oom(module); + } + + sam_name = (const char *)ldb_get_opaque(ldb, "ldb_url"); + if (strncmp("tdb://", sam_name, 6) == 0) { + sam_name += 6; + } + if (!sam_name) { + talloc_free(tmp_ctx); + return ldb_operr(ldb); + } + filename = talloc_asprintf(tmp_ctx, "%s.d/metadata.tdb", sam_name); + if (!filename) { + talloc_free(tmp_ctx); + return ldb_oom(ldb); + } + + open_flags = O_RDWR; + if (stat(filename, &statbuf) != 0) { + talloc_free(tmp_ctx); + return LDB_ERR_OPERATIONS_ERROR; + } + + lp_ctx = talloc_get_type_abort(ldb_get_opaque(ldb, "loadparm"), + struct loadparm_context); + + data->metadata = tdb_wrap_open(data, filename, 10, + TDB_DEFAULT, open_flags, 0660, + lp_ctx); + if (data->metadata == NULL) { + talloc_free(tmp_ctx); + return LDB_ERR_OPERATIONS_ERROR; + } + + talloc_free(tmp_ctx); + return LDB_SUCCESS; +} + +static int schema_metadata_get_uint64(struct ldb_module *module, + const char *key, uint64_t *value, + uint64_t default_value) +{ + struct schema_load_private_data *data = talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data); + struct tdb_context *tdb; + TDB_DATA tdb_key, tdb_data; + char *value_str; + TALLOC_CTX *tmp_ctx; + + if (!data || !data->metadata) { + return ldb_module_error(module, LDB_ERR_OPERATIONS_ERROR, + "schema: metadata tdb not initialized"); + } + + tmp_ctx = talloc_new(NULL); + if (tmp_ctx == NULL) { + return ldb_module_oom(module); + } + + tdb = data->metadata->tdb; + + tdb_key.dptr = (uint8_t *)discard_const_p(char, key); + tdb_key.dsize = strlen(key); + + tdb_data = tdb_fetch_compat(tdb, tdb_key); + if (!tdb_data.dptr) { + if (tdb_error(tdb) == TDB_ERR_NOEXIST) { + *value = default_value; + return LDB_SUCCESS; + } else { + return ldb_module_error(module, LDB_ERR_OPERATIONS_ERROR, + tdb_errorstr_compat(tdb)); + } + } + + value_str = talloc_strndup(tmp_ctx, (char *)tdb_data.dptr, tdb_data.dsize); + if (value_str == NULL) { + SAFE_FREE(tdb_data.dptr); + talloc_free(tmp_ctx); + return ldb_module_oom(module); + } + + *value = strtoull(value_str, NULL, 10); + + SAFE_FREE(tdb_data.dptr); + talloc_free(tmp_ctx); + + return LDB_SUCCESS; +} + static struct dsdb_schema *dsdb_schema_refresh(struct ldb_module *module, struct dsdb_schema *schema, bool is_global_schema) { - uint64_t current_usn; + uint64_t current_usn, value; int ret; struct ldb_result *res; struct ldb_request *treq; @@ -104,6 +219,15 @@ static struct dsdb_schema *dsdb_schema_refresh(struct ldb_module *module, struct * actually changed (and therefor completely reloaded) we would * continue to hit the database to get the highest USN. */ + + ret = schema_metadata_get_uint64(module, DSDB_METADATA_SCHEMA_SEQ_NUM, &value, 0); + if (ret == LDB_SUCCESS) { + schema->metadata_usn = value; + } else { + /* From an old provision it can happen that the tdb didn't exists yet */ + DEBUG(0, ("Error while searching for the schema usn in the metadata\n")); + schema->metadata_usn = 0; + } schema->last_refresh = ts; ctrl = talloc(treq, struct dsdb_control_current_partition); @@ -311,14 +435,71 @@ static int schema_load_init(struct ldb_module *module) current_usn = 0; } - return dsdb_schema_from_db(module, schema_dn, current_usn, &schema); + ret = dsdb_schema_from_db(module, schema_dn, current_usn, &schema); + /* We don't care too much on the result of this action + * the most probable reason for this to fail is that the tdb didn't + * exists yet and this will be corrected by the partition module. + */ + if (ret == LDB_SUCCESS && schema_metadata_open(module) == LDB_SUCCESS) { + uint64_t value; + + ret = schema_metadata_get_uint64(module, DSDB_METADATA_SCHEMA_SEQ_NUM, &value, 0); + if (ret == LDB_SUCCESS) { + schema->metadata_usn = value; + } else { + schema->metadata_usn = 0; + } + } + return ret; +} + +static int schema_search(struct ldb_module *module, struct ldb_request *req) +{ + struct dsdb_schema *schema; + struct ldb_context *ldb = ldb_module_get_ctx(module); + uint64_t value; + int ret; + struct schema_load_private_data *private_data = + talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data); + + schema = dsdb_get_schema(ldb, NULL); + if (schema && private_data && !private_data->in_transaction) { + ret = schema_metadata_get_uint64(module, DSDB_METADATA_SCHEMA_SEQ_NUM, &value, 0); + if (ret == LDB_SUCCESS && schema->metadata_usn < value) { + /* The usn of the schema was changed in the metadata, + * this indicate that another process has modified the schema and + * that a reload is needed. + */ + schema->last_refresh = 0; + schema = dsdb_get_schema(ldb, NULL); + } + } + + return ldb_next_request(module, req); } 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); + struct dsdb_schema *schema; + struct ldb_context *ldb = ldb_module_get_ctx(module); + uint64_t value; + int ret; + schema = dsdb_get_schema(ldb, NULL); + if (!private_data->metadata) { + schema_metadata_open(module); + } + ret = schema_metadata_get_uint64(module, DSDB_METADATA_SCHEMA_SEQ_NUM, &value, 0); + if (ret == LDB_SUCCESS && schema->metadata_usn < value) { + /* The usn of the schema was changed in the metadata, + * this indicate that another process has modified the schema and + * that a reload is needed. + */ + schema->last_refresh = 0; + schema = dsdb_get_schema(ldb, NULL); + } private_data->in_transaction = true; return ldb_next_start_trans(module); @@ -372,6 +553,7 @@ static const struct ldb_module_ops ldb_schema_load_module_ops = { .name = "schema_load", .init_context = schema_load_init, .extended = schema_load_extended, + .search = schema_search, .start_transaction = schema_load_start_transaction, .end_transaction = schema_load_end_transaction, .del_transaction = schema_load_del_transaction, diff --git a/source4/dsdb/schema/schema.h b/source4/dsdb/schema/schema.h index b2f7bac1d18..b7ea09ead80 100644 --- a/source4/dsdb/schema/schema.h +++ b/source4/dsdb/schema/schema.h @@ -247,7 +247,14 @@ struct dsdb_schema { bool refresh_in_progress; time_t ts_last_change; time_t last_refresh; - /* an 'opaque' sequence number that the reload function may also wish to use */ + /* This 'opaque' is stored in the metadata and is used by one process to signal + * that others have to reload the schema + */ + uint64_t metadata_usn; + /* an 'opaque' sequence number that is used in the reload to check if a reload + * should really be performed, as the schema is periodically reloaded this + * is still needed in order to avoid costly complete schema reload. + */ uint64_t reload_seq_number; /* Should the syntax handlers in this case handle all incoming OIDs automatically, assigning them as an OID if no text name is known? */ -- 2.34.1