ldb_search returns LDB_ERR_NO_SUCH_OBJECT when searching for prefixMap from module

[Anatoliy Atanasov]

Hi List, 

I added a module in dsdb/samdb/ldb_modules called prefix_map. All I need in my init function is to get the prefix map and store it, 
but I fail when I do ldb_search with error LDB_ERR_NO_SUCH_OBJECT.
I tried to copy/paste the code from schema_fsmo_init method and it doesn't work in my function also.
I guess my module is not called when it should.

Here is what I have done so far.

I added it to the build system in dsdb/samdb/ldb_modules/config.mk


################################################
# Start MODULE ldb_prefix_map
[MODULE::ldb_prefix_map]
INIT_FUNCTION = LDB_MODULE(prefix_map)
CFLAGS = -Ilib/ldb/include
OUTPUT_TYPE = SHARED_LIBRARY
PRIVATE_DEPENDENCIES = SAMDB LIBTALLOC LIBNDR NDR_MISC NDR_DRSUAPI \
					   NDR_DRSBLOBS LIBNDR
SUBSYSTEM = LIBLDB
# End MODULE ldb_prefix_map
################################################

ldb_prefix_map_OBJ_FILES = $(dsdbsrcdir)/samdb/ldb_modules/prefix_map.o


Edited the scripting/python/samba/provision.py to put it in the chain

modules_list = ["rootdse",
                    "paged_results",
                    "ranged_results",
                    "anr",
                    "server_sort",
                    "extended_dn",
                    "asq",
                    "rdn_name",
                    "objectclass",
                    "samldb",
                    "kludge_acl",
                    "operational",
                    "prefix_map"]

And added code to the .init_context function

static int prefix_map_init(struct ldb_module *module)
{
	const struct ldb_val    *prefix_val;
    struct ldb_val          *prefix_map_string;
    struct ldb_dn           *schema_dn;
    struct ldb_result       *schema_res;
    int                     ret;
    TALLOC_CTX              *mem_ctx;
    static const char *schema_attrs[] = {
		"prefixMap",
		NULL
	};
	    
    schema_dn = samdb_schema_dn(module->ldb);
    if (!schema_dn) {
		ldb_reset_err_string(module->ldb);
		ldb_debug(module->ldb, LDB_DEBUG_WARNING,
            "prefix_map_init: no schema dn present: (skip prefix map init)\n");
		return ldb_next_init(module);
	}

	mem_ctx = talloc_new(module);
	if (!mem_ctx) {
		ldb_debug(module->ldb, LDB_DEBUG_WARNING,
            "prefix_map_init: talloc failed: (skip prefix map init)\n");
		return ldb_next_init(module);
	}
    
    ret = ldb_search(module->ldb, schema_dn,
			        LDB_SCOPE_BASE,
			        NULL, schema_attrs,
			        &schema_res);
	if (ret == LDB_ERR_NO_SUCH_OBJECT) {
		ldb_reset_err_string(module->ldb);
		ldb_debug(module->ldb, LDB_DEBUG_WARNING,
			        "prefix_map_init: no prefix map present: (skip prefix map init)\n");
		talloc_free(mem_ctx);
		return ldb_next_init(module);
	} else if (ret != LDB_SUCCESS) {
		ldb_asprintf_errstring(module->ldb,
				                "prefix_map_init: failed to search the schema head: %s",
				                ldb_errstring(module->ldb));
		talloc_free(mem_ctx);
		return ret;
	}

    prefix_val = ldb_msg_find_ldb_val(schema_res->msgs[0], "prefixMap");
	if (!prefix_val) {
		ldb_debug_set(module->ldb, LDB_DEBUG_FATAL,
			        "prefix_map_init: no prefixMap attribute found");
		talloc_free(mem_ctx);
		return ldb_next_init(module);
	}
    
    prefix_map_string = talloc( mem_ctx, struct ldb_val );
    if ( !ldif_write_prefixMap(module->ldb, mem_ctx, prefix_val, prefix_map_string) ) {
        ldb_debug_set(module->ldb, LDB_DEBUG_FATAL,
			        "prefix_map_init: cannot convert a NDR formatted blob to a ldif formatted prefixMap");
		talloc_free(mem_ctx);
		return ldb_next_init(module);
    }
    
    talloc_free(mem_ctx);
    return ldb_next_init(module);
}

Regards, 
Anatoliy Atanasov