Skip to content

CDRIVER-5864 Do not parse BSON in mongoc_server_description_new_copy #1835

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 5 commits into from
Feb 4, 2025
Merged

CDRIVER-5864 Do not parse BSON in mongoc_server_description_new_copy #1835

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
9da57f8
do not parse BSON in `mongoc_server_description_new_copy`
kevinAlbs Jan 23, 2025
5d84208
remove unnecessary atomic modification of `round_trip_time_msec`
kevinAlbs Jan 24, 2025
ca372a3
add tests for copying
kevinAlbs Jan 24, 2025
392f83e
remove unnecessary `bson_init`
kevinAlbs Jan 27, 2025
2c84319
add debug assertions
kevinAlbs Jan 27, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
120 changes: 83 additions & 37 deletions src/libmongoc/src/mongoc/mongoc-server-description.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -485,11 +485,9 @@ mongoc_server_description_update_rtt (mongoc_server_description_t *server, int64
return;
}
if (server->round_trip_time_msec == MONGOC_RTT_UNSET) {
mcommon_atomic_int64_exchange (&server->round_trip_time_msec, rtt_msec, mcommon_memory_order_relaxed);
server->round_trip_time_msec = rtt_msec;
} else {
mcommon_atomic_int64_exchange (&server->round_trip_time_msec,
(int64_t) (ALPHA * rtt_msec + (1 - ALPHA) * server->round_trip_time_msec),
mcommon_memory_order_relaxed);
server->round_trip_time_msec = (int64_t) (ALPHA * rtt_msec + (1 - ALPHA) * server->round_trip_time_msec);
}
}

Expand Down Expand Up @@ -768,48 +766,96 @@ mongoc_server_description_handle_hello (mongoc_server_description_t *sd,
mongoc_server_description_t *
mongoc_server_description_new_copy (const mongoc_server_description_t *description)
{
mongoc_server_description_t *copy;
#define COPY_FIELD(FIELD) \
if (1) { \
copy->FIELD = description->FIELD; \
} else \
(void) 0


#define COPY_BSON_FIELD(FIELD) \
if (1) { \
bson_copy_to (&description->FIELD, &copy->FIELD); \
} else \
(void) 0

// COPY_INTERNAL_BSON_FIELD copies a `bson_t` that references data in `last_hello_response`.
#define COPY_INTERNAL_BSON_FIELD(FIELD) \
if (1) { \
if (!bson_empty (&description->FIELD)) { \
ptrdiff_t offset = bson_get_data (&description->FIELD) - bson_get_data (&description->last_hello_response); \
MONGOC_DEBUG_ASSERT (offset >= 0); \
const uint8_t *data = bson_get_data (&copy->last_hello_response) + offset; \
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I know this is a performance patch, but it might still be worth bounds-checking 'offset' here? This might be a good place for a debug-only or asan-only assertion.

Copy link
Collaborator Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added debug-only assertions with MONGOC_DEBUG_ASSERT

uint32_t len = description->FIELD.len; \
MONGOC_DEBUG_ASSERT (offset + len <= copy->last_hello_response.len); \
bson_init_static (&copy->FIELD, data, len); \
} else { \
bson_init (&copy->FIELD); \
} \
} else \
(void) 0

// COPY_INTERNAL_STRING_FIELD copies a `const char*` that references data in `last_hello_response`.
#define COPY_INTERNAL_STRING_FIELD(FIELD) \
if (1) { \
if (description->FIELD) { \
ptrdiff_t offset = (char *) description->FIELD - (char *) bson_get_data (&description->last_hello_response); \
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This might be a good place for an asan-only assertion too, since it would require a heavy strlen check.

MONGOC_DEBUG_ASSERT (offset >= 0); \
copy->FIELD = (char *) bson_get_data (&copy->last_hello_response) + offset; \
MONGOC_DEBUG_ASSERT (offset + strlen (description->FIELD) <= copy->last_hello_response.len); \
} else { \
copy->FIELD = NULL; \
} \
} else \
(void) 0


if (!description) {
return NULL;
}

copy = BSON_ALIGNED_ALLOC0 (mongoc_server_description_t);

copy->id = description->id;
copy->opened = description->opened;
memcpy (&copy->host, &description->host, sizeof (copy->host));
copy->round_trip_time_msec = MONGOC_RTT_UNSET;
mongoc_server_description_t *copy = BSON_ALIGNED_ALLOC (mongoc_server_description_t);

COPY_FIELD (id);
COPY_FIELD (host);
COPY_FIELD (round_trip_time_msec);
COPY_FIELD (last_update_time_usec);
COPY_BSON_FIELD (last_hello_response);
COPY_FIELD (has_hello_response);
COPY_FIELD (hello_ok);
copy->connection_address = copy->host.host_and_port;
bson_init (&copy->last_hello_response);
bson_init (&copy->hosts);
bson_init (&copy->passives);
bson_init (&copy->arbiters);
bson_init (&copy->tags);
bson_init (&copy->compressors);
bson_copy_to (&description->topology_version, &copy->topology_version);
bson_oid_copy (&description->service_id, &copy->service_id);
copy->server_connection_id = description->server_connection_id;

if (description->has_hello_response) {
/* calls mongoc_server_description_reset */
int64_t last_rtt_ms =
mcommon_atomic_int64_fetch (&description->round_trip_time_msec, mcommon_memory_order_relaxed);
mongoc_server_description_handle_hello (
copy, &description->last_hello_response, last_rtt_ms, &description->error);
} else {
mongoc_server_description_reset (copy);
/* preserve the original server description type, which is manually set
* for a LoadBalancer server */
copy->type = description->type;
}
COPY_INTERNAL_STRING_FIELD (me);
COPY_FIELD (opened);
COPY_INTERNAL_STRING_FIELD (set_name);
COPY_FIELD (error);
COPY_FIELD (type);
COPY_FIELD (min_wire_version);
COPY_FIELD (max_wire_version);
COPY_FIELD (max_msg_size);
COPY_FIELD (max_bson_obj_size);
COPY_FIELD (max_write_batch_size);
COPY_FIELD (session_timeout_minutes);
COPY_INTERNAL_BSON_FIELD (hosts);
COPY_INTERNAL_BSON_FIELD (passives);
COPY_INTERNAL_BSON_FIELD (arbiters);
COPY_INTERNAL_BSON_FIELD (tags);
COPY_INTERNAL_STRING_FIELD (current_primary);
COPY_FIELD (set_version);
COPY_FIELD (election_id);
COPY_FIELD (last_write_date_ms);
COPY_INTERNAL_BSON_FIELD (compressors);
// `topology_version` does not refer to data in `last_hello_response`. It needs to outlive `last_hello_response`.
COPY_BSON_FIELD (topology_version);
COPY_FIELD (generation);
copy->_generation_map_ = mongoc_generation_map_copy (mc_tpl_sd_generation_map_const (description));
COPY_FIELD (service_id);
COPY_FIELD (server_connection_id);

/* Preserve the error */
memcpy (&copy->error, &description->error, sizeof copy->error);
#undef COPY_INTERNAL_STRING_FIELD
#undef COPY_INTERNAL_BSON_FIELD
#undef COPY_BSON_FIELD
#undef COPY_FIELD

copy->generation = description->generation;
copy->_generation_map_ = mongoc_generation_map_copy (mc_tpl_sd_generation_map_const (description));
return copy;
}

Expand Down
114 changes: 114 additions & 0 deletions src/libmongoc/tests/test-mongoc-server-description.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -458,6 +458,119 @@ test_server_description_hello_type_error (void)
mongoc_server_description_cleanup (&sd);
}

static void
test_copy (const char *hello_json)
{
mongoc_server_description_t sd, *sd_copy;
mongoc_server_description_init (&sd, "host:1234", 1);
bson_error_t empty_error = {0};
mongoc_server_description_handle_hello (&sd, tmp_bson (hello_json), 0, &empty_error);
sd_copy = mongoc_server_description_new_copy (&sd);

// Check server descriptions compare equal by "Server Description Equality" rules. Not all fields are considered.
ASSERT (_mongoc_server_description_equal (&sd, sd_copy));

// Check all fields:
ASSERT_CMPUINT32 (sd.id, ==, sd_copy->id);
ASSERT_CMPSTR (sd.host.host_and_port, sd_copy->host.host_and_port);
ASSERT_CMPINT64 (sd.round_trip_time_msec, ==, sd_copy->round_trip_time_msec);
ASSERT_CMPINT64 (sd.last_update_time_usec, ==, sd_copy->last_update_time_usec);
ASSERT_EQUAL_BSON (&sd.last_hello_response, &sd_copy->last_hello_response);
ASSERT_CMPINT ((int) sd.has_hello_response, ==, (int) sd_copy->has_hello_response);
ASSERT_CMPINT ((int) sd.hello_ok, ==, (int) sd_copy->hello_ok);
ASSERT_CMPSTR (sd.connection_address, sd_copy->connection_address);
ASSERT_CMPSTR (sd.me, sd_copy->me);
ASSERT_CMPINT ((int) sd.opened, ==, (int) sd_copy->opened);
ASSERT_CMPSTR (sd.set_name, sd_copy->set_name);
ASSERT_MEMCMP (&sd.error, &sd_copy->error, (int) sizeof (bson_error_t));
ASSERT_CMPINT ((int) sd.type, ==, (int) sd_copy->type);
ASSERT_CMPINT32 (sd.min_wire_version, ==, sd_copy->min_wire_version);
ASSERT_CMPINT32 (sd.max_wire_version, ==, sd_copy->max_wire_version);
ASSERT_CMPINT32 (sd.max_msg_size, ==, sd_copy->max_msg_size);
ASSERT_CMPINT32 (sd.max_bson_obj_size, ==, sd_copy->max_bson_obj_size);
ASSERT_CMPINT32 (sd.max_write_batch_size, ==, sd_copy->max_write_batch_size);
ASSERT_CMPINT64 (sd.session_timeout_minutes, ==, sd_copy->session_timeout_minutes);
ASSERT_EQUAL_BSON (&sd.hosts, &sd_copy->hosts);
ASSERT_EQUAL_BSON (&sd.passives, &sd_copy->passives);
ASSERT_EQUAL_BSON (&sd.arbiters, &sd_copy->arbiters);
ASSERT_EQUAL_BSON (&sd.tags, &sd_copy->tags);
ASSERT_CMPSTR (sd.current_primary, sd_copy->current_primary);
ASSERT_CMPINT64 (sd.set_version, ==, sd_copy->set_version);
ASSERT_MEMCMP (&sd.election_id, &sd_copy->election_id, (int) sizeof (bson_oid_t));
ASSERT_CMPINT64 (sd.last_write_date_ms, ==, sd_copy->last_write_date_ms);
ASSERT_EQUAL_BSON (&sd.compressors, &sd_copy->compressors);
ASSERT_EQUAL_BSON (&sd.topology_version, &sd_copy->topology_version);
ASSERT_CMPUINT32 (sd.generation, ==, sd_copy->generation);
ASSERT (sd_copy->_generation_map_ != NULL); // Do not compare entries. Just ensure non-NULL.
ASSERT_MEMCMP (&sd.service_id, &sd_copy->service_id, (int) sizeof (bson_oid_t));
ASSERT_CMPINT64 (sd.server_connection_id, ==, sd_copy->server_connection_id);

mongoc_server_description_cleanup (&sd);
mongoc_server_description_destroy (sd_copy);
}

static void
test_server_description_copy (void)
{
const char *hello_mongod = BSON_STR ({
"topologyVersion" : {"processId" : {"$oid" : "6792ef87965dee8797402adb"}, "counter" : 6},
"hosts" : ["localhost:27017"],
"setName" : "rs0",
"setVersion" : 1,
"isWritablePrimary" : true,
"secondary" : false,
"primary" : "localhost:27017",
"me" : "localhost:27017",
"electionId" : {"$oid" : "7fffffff0000000000000016"},
"lastWrite" : {
"opTime" : {"ts" : {"$timestamp" : {"t" : 1737682844, "i" : 1}}, "t" : 22},
"lastWriteDate" : {"$date" : "2025-01-24T01:40:44Z"},
"majorityOpTime" : {"ts" : {"$timestamp" : {"t" : 1737682844, "i" : 1}}, "t" : 22},
"majorityWriteDate" : {"$date" : "2025-01-24T01:40:44Z"}
},
"maxBsonObjectSize" : 16777216,
"maxMessageSizeBytes" : 48000000,
"maxWriteBatchSize" : 100000,
"localTime" : {"$date" : "2025-01-24T01:40:51.968Z"},
"logicalSessionTimeoutMinutes" : 30,
"connectionId" : 13,
"minWireVersion" : 0,
"maxWireVersion" : 25,
"readOnly" : false,
"ok" : 1.0,
"$clusterTime" : {
"clusterTime" : {"$timestamp" : {"t" : 1737682844, "i" : 1}},
"signature" :
{"hash" : {"$binary" : {"base64" : "AAAAAAAAAAAAAAAAAAAAAAAAAAA=", "subType" : "00"}}, "keyId" : 0}
},
"operationTime" : {"$timestamp" : {"t" : 1737682844, "i" : 1}}
});

const char *hello_mongos = BSON_STR ({
"isWritablePrimary" : true,
"msg" : "isdbgrid",
"topologyVersion" : {"processId" : {"$oid" : "6791af1181771f367602ec40"}, "counter" : 0},
"maxBsonObjectSize" : 16777216,
"maxMessageSizeBytes" : 48000000,
"maxWriteBatchSize" : 100000,
"localTime" : {"$date" : "2025-01-24T01:24:57.217Z"},
"logicalSessionTimeoutMinutes" : 30,
"connectionId" : 3310,
"maxWireVersion" : 25,
"minWireVersion" : 0,
"ok" : 1.0,
"$clusterTime" : {
"clusterTime" : {"$timestamp" : {"t" : 1737681896, "i" : 1}},
"signature" :
{"hash" : {"$binary" : {"base64" : "AAAAAAAAAAAAAAAAAAAAAAAAAAA=", "subType" : "00"}}, "keyId" : 0}
},
"operationTime" : {"$timestamp" : {"t" : 1737681896, "i" : 1}}
});

test_copy (hello_mongod);
test_copy (hello_mongos);
}

void
test_server_description_install (TestSuite *suite)
{
Expand All @@ -470,4 +583,5 @@ test_server_description_install (TestSuite *suite)
TestSuite_Add (suite, "/server_description/legacy_hello_ok", test_server_description_legacy_hello_ok);
TestSuite_Add (suite, "/server_description/connection_id", test_server_description_connection_id);
TestSuite_Add (suite, "/server_description/hello_type_error", test_server_description_hello_type_error);
TestSuite_Add (suite, "/server_description/copy", test_server_description_copy);
}