From 3ac78c7a7a42afbbc9cb09c03b568c1c39cd035c Mon Sep 17 00:00:00 2001 From: Hayato Kuroda Date: Wed, 19 Feb 2025 11:37:26 +0900 Subject: [PATCH v5 2/2] Prohibit slot manipulation while in single-user mode Replication-related commands are rarely used in single-user mode and have been broken for years. This commit prohibits calling slot manipulation SQL functions to avoid additional risk of failures. One exception is pg_drop_replication_slot. It is still allowed because users may want to clean up their mistakes in the mode. --- doc/src/sgml/func/func-admin.sgml | 5 +++++ src/backend/replication/logical/logicalfuncs.c | 3 +++ src/backend/replication/slot.c | 12 ++++++++++++ src/backend/replication/slotfuncs.c | 17 +++++++++++++++++ src/backend/utils/adt/pg_upgrade_support.c | 3 +++ src/include/replication/slot.h | 1 + 6 files changed, 41 insertions(+) diff --git a/doc/src/sgml/func/func-admin.sgml b/doc/src/sgml/func/func-admin.sgml index 446fdfe56f4..cfa09e4b987 100644 --- a/doc/src/sgml/func/func-admin.sgml +++ b/doc/src/sgml/func/func-admin.sgml @@ -1012,6 +1012,11 @@ postgres=# SELECT '0/0'::pg_lsn + pd.segment_number * ps.setting::int + :offset are also relevant for replication. + + Note that slot manipulation functions except pg_drop_replication_slot + cannot be used in single-user mode. + + Replication Management Functions diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index ca53caac2f2..30877fdc3ab 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -113,6 +113,9 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin List *options = NIL; DecodingOutputState *p; + /* Slot manipulation is not allowed in single-user mode */ + CheckSlotIsInSingleUserMode(); + CheckSlotPermissions(); CheckLogicalDecodingRequirements(); diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index fd0fdb96d42..4ca1227cc94 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -1529,6 +1529,18 @@ CheckSlotPermissions(void) "REPLICATION"))); } +/* + * Check whether the instance is in single-user mode. + */ +void +CheckSlotIsInSingleUserMode(void) +{ + if (!IsUnderPostmaster) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots cannot be used in single-user mode"))); +} + /* * Reserve WAL for the currently active slot. * diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 69f4c6157c5..4de2e52fba9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -17,6 +17,7 @@ #include "access/xlogrecovery.h" #include "access/xlogutils.h" #include "funcapi.h" +#include "miscadmin.h" #include "replication/logical.h" #include "replication/slot.h" #include "replication/slotsync.h" @@ -76,6 +77,9 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE) elog(ERROR, "return type must be a row type"); + /* Slot manipulation is not allowed in single-user mode */ + CheckSlotIsInSingleUserMode(); + CheckSlotPermissions(); CheckSlotRequirements(); @@ -182,6 +186,9 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE) elog(ERROR, "return type must be a row type"); + /* Slot manipulation is not allowed in single-user mode */ + CheckSlotIsInSingleUserMode(); + CheckSlotPermissions(); CheckLogicalDecodingRequirements(); @@ -521,6 +528,9 @@ pg_replication_slot_advance(PG_FUNCTION_ARGS) Assert(!MyReplicationSlot); + /* Slot manipulation is not allowed in single-user mode */ + CheckSlotIsInSingleUserMode(); + CheckSlotPermissions(); if (XLogRecPtrIsInvalid(moveto)) @@ -618,9 +628,13 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) TupleDesc tupdesc; HeapTuple tuple; + if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE) elog(ERROR, "return type must be a row type"); + /* Slot manipulation is not allowed in single-user mode */ + CheckSlotIsInSingleUserMode(); + CheckSlotPermissions(); if (logical_slot) @@ -898,6 +912,9 @@ pg_sync_replication_slots(PG_FUNCTION_ARGS) char *err; StringInfoData app_name; + /* Slot manipulation is not allowed in single-user mode */ + CheckSlotIsInSingleUserMode(); + CheckSlotPermissions(); if (!RecoveryInProgress()) diff --git a/src/backend/utils/adt/pg_upgrade_support.c b/src/backend/utils/adt/pg_upgrade_support.c index a4f8b4faa90..337f705b34b 100644 --- a/src/backend/utils/adt/pg_upgrade_support.c +++ b/src/backend/utils/adt/pg_upgrade_support.c @@ -296,6 +296,9 @@ binary_upgrade_logical_slot_has_caught_up(PG_FUNCTION_ARGS) */ Assert(has_rolreplication(GetUserId())); + /* Slot manipulation is not allowed in single-user mode */ + CheckSlotIsInSingleUserMode(); + slot_name = PG_GETARG_NAME(0); /* Acquire the given slot */ diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index e8fc342d1a9..b4d89760f96 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -342,6 +342,7 @@ extern void CheckPointReplicationSlots(bool is_shutdown); extern void CheckSlotRequirements(void); extern void CheckSlotPermissions(void); +extern void CheckSlotIsInSingleUserMode(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); extern const char *GetSlotInvalidationCauseName(ReplicationSlotInvalidationCause cause); -- 2.47.1