box: fix null pointer dereference in exact_key_validate

Fixed a null pointer dereference in `exact_key_validate`. When you tried
to `get()` with an incorrect key format (`ER_EXACT_MATCH`) in `read_view`
from deleted space, a null pointer was dereferenced and tarantool crashed.

Needed for tarantool/tarantool-ee#787

NO_DOC=bugfix
NO_TEST=ee

changelogs/unreleased/ghe-787-fix-null-pointer-dereference-in-exact_key_validate.md

@@ -0,0 +1,3 @@
+## bugfix/box
+
+* Fixed a null pointer dereference when an `ER_EXACT_MATCH` error occurred on an attempt to call `get()` in a `read_view` from the deleted space. (ghe-787).

src/box/index.cc

@@ -99,8 +99,7 @@ error_set_index(struct error *error, const struct index_def *index_def)
 {
 	error_set_str(error, "index", index_def->name);
 	error_set_uint(error, "index_id", index_def->iid);
-	struct space *space = space_by_id(index_def->space_id);
-	error_set_str(error, "space", space->def->name);
+	error_set_str(error, "space", index_def->space_name);
 	error_set_uint(error, "space_id", index_def->space_id);
 }
 
@@ -218,10 +217,8 @@ index_check_dup(struct index *index, struct tuple *old_tuple,
 			 * dup_replace_mode is DUP_REPLACE, and
 			 * a tuple with the same key is not found.
 			 */
-			struct space *space = space_by_id(index->def->space_id);
-			assert(space != NULL);
 			diag_set(ClientError, ER_CANT_UPDATE_PRIMARY_KEY,
-				 space->def->name, space->def->id,
+				 index->def->space_name, index->def->space_id,
 				 old_tuple, new_tuple, NULL);
 			return -1;
 		}
@@ -234,10 +231,8 @@ index_check_dup(struct index *index, struct tuple *old_tuple,
 			 * possibly delete more than one tuple
 			 * at once.
 			 */
-			struct space *space = space_by_id(index->def->space_id);
-			assert(space != NULL);
 			diag_set(ClientError, ER_TUPLE_FOUND,
-				 index->def->name, space->def->name,
+				 index->def->name, index->def->space_name,
 				 tuple_str(dup_tuple), tuple_str(new_tuple),
 				 dup_tuple, new_tuple);
 			return -1;

src/box/index_def.c

@@ -35,6 +35,7 @@
 #include "json/json.h"
 #include "fiber.h"
 #include "tt_static.h"
+#include "space_cache.h"
 
 const char *index_type_strs[] = { "HASH", "TREE", "BITSET", "RTREE" };
 
@@ -133,6 +134,7 @@ index_def_new(uint32_t space_id, uint32_t iid, const char *name,
 	}
 	def->type = type;
 	def->space_id = space_id;
+	def->space_name = NULL;
 	def->iid = iid;
 	def->opts = *opts;
 	return def;
@@ -144,6 +146,8 @@ index_def_dup(const struct index_def *def)
 	struct index_def *dup = xmalloc(sizeof(*dup));
 	*dup = *def;
 	dup->name = xstrdup(def->name);
+	if (def->space_name)
+		dup->space_name = xstrdup(def->space_name);
 	dup->key_def = key_def_dup(def->key_def);
 	dup->cmp_def = key_def_dup(def->cmp_def);
 	dup->pk_def = key_def_dup(def->pk_def);
@@ -157,6 +161,8 @@ index_def_delete(struct index_def *index_def)
 {
 	index_opts_destroy(&index_def->opts);
 	free(index_def->name);
+	if (index_def->space_name)
+		free(index_def->space_name);
 
 	if (index_def->key_def)
 		key_def_delete(index_def->key_def);

src/box/index_def.h

@@ -166,6 +166,8 @@ struct index_def {
 	uint32_t iid;
 	/* Space id. */
 	uint32_t space_id;
+	/* Space name. */
+	char *space_name;
 	/** Index name. */
 	char *name;
 	/** Index type. */

src/box/key_list.c

@@ -63,50 +63,44 @@ key_list_iterator_create(struct key_list_iterator *it, struct tuple *tuple,
 	port_destroy(&in_port);
 	if (rc != 0) {
 		/* Can't evaluate function. */
-		struct space *space = space_by_id(index_def->space_id);
 		diag_add(ClientError, ER_FUNC_INDEX_FUNC, index_def->name,
-			 space ? space_name(space) : "",
-			 "can't evaluate function");
+			 index_def->space_name, "can't evaluate function");
 		return -1;
 	}
 	uint32_t key_data_sz;
 	const char *key_data = port_get_msgpack(&out_port, &key_data_sz);
 	port_destroy(&out_port);
 	if (key_data == NULL) {
-		struct space *space = space_by_id(index_def->space_id);
 		/* Can't get a result returned by function . */
-		diag_add(ClientError, ER_FUNC_INDEX_FUNC, index_def->name,
-			 space ? space_name(space) : "",
+		diag_add(ClientError, ER_FUNC_INDEX_FUNC,
+			 index_def->name, index_def->space_name,
 			 "can't get a value returned by function");
 		return -1;
 	}
 
 	it->data_end = key_data + key_data_sz;
 	assert(mp_typeof(*key_data) == MP_ARRAY);
 	if (mp_decode_array(&key_data) != 1) {
-		struct space *space = space_by_id(index_def->space_id);
 		/*
 		 * Function return doesn't follow the
 		 * convention: to many values were returned.
 		 * i.e. return 1, 2
 		 */
 		region_truncate(region, region_svp);
-		diag_set(ClientError, ER_FUNC_INDEX_FORMAT, index_def->name,
-			 space ? space_name(space) : "",
+		diag_set(ClientError, ER_FUNC_INDEX_FORMAT,
+			 index_def->name, index_def->space_name,
 			 "to many values were returned");
 		return -1;
 	}
 	if (func->def->opts.is_multikey) {
 		if (mp_typeof(*key_data) != MP_ARRAY) {
-			struct space * space = space_by_id(index_def->space_id);
 			/*
 			 * Multikey function must return an array
 			 * of keys.
 			 */
 			region_truncate(region, region_svp);
 			diag_set(ClientError, ER_FUNC_INDEX_FORMAT,
-				 index_def->name,
-				 space ? space_name(space) : "",
+				 index_def->name, index_def->space_name,
 				 "a multikey function mustn't return a scalar");
 			return -1;
 		}
@@ -138,13 +132,12 @@ key_list_iterator_next(struct key_list_iterator *it, struct tuple **value)
 	}
 
 	if (mp_typeof(*key) != MP_ARRAY) {
-		struct space *space = space_by_id(it->index_def->space_id);
 		/*
 		 * A value returned by func_index function is
 		 * not a valid key, i.e. {1}.
 		 */
-		diag_set(ClientError, ER_FUNC_INDEX_FORMAT, it->index_def->name,
-			 space ? space_name(space) : "",
+		diag_set(ClientError, ER_FUNC_INDEX_FORMAT,
+			 it->index_def->name, it->index_def->space_name,
 			 tt_sprintf("supplied key type is invalid: expected %s",
 				    field_type_strs[FIELD_TYPE_ARRAY]));
 		return -1;
@@ -153,26 +146,24 @@ key_list_iterator_next(struct key_list_iterator *it, struct tuple **value)
 	const char *rptr = key;
 	uint32_t part_count = mp_decode_array(&rptr);
 	if (part_count != key_def->part_count) {
-		struct space *space = space_by_id(it->index_def->space_id);
 		/*
 		 * The key must have exact functional index
 		 * definition's part_count(s).
 		 */
-		diag_set(ClientError, ER_FUNC_INDEX_FORMAT, it->index_def->name,
-			 space ? space_name(space) : "",
+		diag_set(ClientError, ER_FUNC_INDEX_FORMAT,
+			 it->index_def->name, it->index_def->space_name,
 			 tt_sprintf(tnt_errcode_desc(ER_EXACT_MATCH),
 				   key_def->part_count, part_count));
 		return -1;
 	}
 	if (key_validate_parts(key_def, rptr, part_count, true,
 			       &key_end) != 0) {
-		struct space *space = space_by_id(it->index_def->space_id);
 		/*
 		 * The key doesn't follow functional index key
 		 * definition.
 		 */
 		diag_add(ClientError, ER_FUNC_INDEX_FORMAT, it->index_def->name,
-			 space ? space_name(space) : "",
+			 it->index_def->name, it->index_def->space_name,
 			 "key does not follow functional index definition");
 		return -1;
 	}

src/box/space.c

@@ -580,6 +580,7 @@ space_create(struct space *space, struct engine *engine,
 		struct index *index = space_create_index(space, index_def);
 		if (index == NULL)
 			goto fail_free_indexes;
+		index->def->space_name = xstrdup(def->name);
 		space->index_map[index_def->iid] = index;
 		if (index_def->opts.is_unique)
 			bit_set(space->check_unique_constraint_map,