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event_trigger.c
2376 lines (2072 loc) · 64.9 KB
/
event_trigger.c
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/*-------------------------------------------------------------------------
*
* event_trigger.c
* PostgreSQL EVENT TRIGGER support code.
*
* Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/commands/event_trigger.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "access/xact.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_event_trigger.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_opfamily.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_trigger.h"
#include "catalog/pg_ts_config.h"
#include "catalog/pg_type.h"
#include "commands/dbcommands.h"
#include "commands/event_trigger.h"
#include "commands/extension.h"
#include "commands/trigger.h"
#include "funcapi.h"
#include "parser/parse_func.h"
#include "pgstat.h"
#include "lib/ilist.h"
#include "miscadmin.h"
#include "tcop/deparse_utility.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/evtcache.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/tqual.h"
#include "utils/syscache.h"
#include "tcop/utility.h"
typedef struct EventTriggerQueryState
{
/* memory context for this state's objects */
MemoryContext cxt;
/* sql_drop */
slist_head SQLDropList;
bool in_sql_drop;
/* table_rewrite */
Oid table_rewrite_oid; /* InvalidOid, or set for table_rewrite
* event */
int table_rewrite_reason; /* AT_REWRITE reason */
/* Support for command collection */
bool commandCollectionInhibited;
CollectedCommand *currentCommand;
List *commandList; /* list of CollectedCommand; see
* deparse_utility.h */
struct EventTriggerQueryState *previous;
} EventTriggerQueryState;
static EventTriggerQueryState *currentEventTriggerState = NULL;
typedef struct
{
const char *obtypename;
bool supported;
} event_trigger_support_data;
typedef enum
{
EVENT_TRIGGER_COMMAND_TAG_OK,
EVENT_TRIGGER_COMMAND_TAG_NOT_SUPPORTED,
EVENT_TRIGGER_COMMAND_TAG_NOT_RECOGNIZED
} event_trigger_command_tag_check_result;
/* XXX merge this with ObjectTypeMap? */
static event_trigger_support_data event_trigger_support[] = {
{"ACCESS METHOD", true},
{"AGGREGATE", true},
{"CAST", true},
{"CONSTRAINT", true},
{"COLLATION", true},
{"CONVERSION", true},
{"DATABASE", false},
{"DOMAIN", true},
{"EXTENSION", true},
{"EVENT TRIGGER", false},
{"FOREIGN DATA WRAPPER", true},
{"FOREIGN TABLE", true},
{"FUNCTION", true},
{"INDEX", true},
{"LANGUAGE", true},
{"MATERIALIZED VIEW", true},
{"OPERATOR", true},
{"OPERATOR CLASS", true},
{"OPERATOR FAMILY", true},
{"POLICY", true},
{"PROCEDURE", true},
{"PUBLICATION", true},
{"ROLE", false},
{"ROUTINE", true},
{"RULE", true},
{"SCHEMA", true},
{"SEQUENCE", true},
{"SERVER", true},
{"STATISTICS", true},
{"SUBSCRIPTION", true},
{"TABLE", true},
{"TABLESPACE", false},
{"TRANSFORM", true},
{"TRIGGER", true},
{"TEXT SEARCH CONFIGURATION", true},
{"TEXT SEARCH DICTIONARY", true},
{"TEXT SEARCH PARSER", true},
{"TEXT SEARCH TEMPLATE", true},
{"TYPE", true},
{"USER MAPPING", true},
{"VIEW", true},
{NULL, false}
};
/* Support for dropped objects */
typedef struct SQLDropObject
{
ObjectAddress address;
const char *schemaname;
const char *objname;
const char *objidentity;
const char *objecttype;
List *addrnames;
List *addrargs;
bool original;
bool normal;
bool istemp;
slist_node next;
} SQLDropObject;
static void AlterEventTriggerOwner_internal(Relation rel,
HeapTuple tup,
Oid newOwnerId);
static event_trigger_command_tag_check_result check_ddl_tag(const char *tag);
static event_trigger_command_tag_check_result check_table_rewrite_ddl_tag(
const char *tag);
static void error_duplicate_filter_variable(const char *defname);
static Datum filter_list_to_array(List *filterlist);
static Oid insert_event_trigger_tuple(const char *trigname, const char *eventname,
Oid evtOwner, Oid funcoid, List *tags);
static void validate_ddl_tags(const char *filtervar, List *taglist);
static void validate_table_rewrite_tags(const char *filtervar, List *taglist);
static void EventTriggerInvoke(List *fn_oid_list, EventTriggerData *trigdata);
static const char *stringify_grant_objtype(ObjectType objtype);
static const char *stringify_adefprivs_objtype(ObjectType objtype);
/*
* Create an event trigger.
*/
Oid
CreateEventTrigger(CreateEventTrigStmt *stmt)
{
HeapTuple tuple;
Oid funcoid;
Oid funcrettype;
Oid fargtypes[1]; /* dummy */
Oid evtowner = GetUserId();
ListCell *lc;
List *tags = NULL;
/*
* It would be nice to allow database owners or even regular users to do
* this, but there are obvious privilege escalation risks which would have
* to somehow be plugged first.
*/
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to create event trigger \"%s\"",
stmt->trigname),
errhint("Must be superuser to create an event trigger.")));
/* Validate event name. */
if (strcmp(stmt->eventname, "ddl_command_start") != 0 &&
strcmp(stmt->eventname, "ddl_command_end") != 0 &&
strcmp(stmt->eventname, "sql_drop") != 0 &&
strcmp(stmt->eventname, "table_rewrite") != 0)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unrecognized event name \"%s\"",
stmt->eventname)));
/* Validate filter conditions. */
foreach(lc, stmt->whenclause)
{
DefElem *def = (DefElem *) lfirst(lc);
if (strcmp(def->defname, "tag") == 0)
{
if (tags != NULL)
error_duplicate_filter_variable(def->defname);
tags = (List *) def->arg;
}
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unrecognized filter variable \"%s\"", def->defname)));
}
/* Validate tag list, if any. */
if ((strcmp(stmt->eventname, "ddl_command_start") == 0 ||
strcmp(stmt->eventname, "ddl_command_end") == 0 ||
strcmp(stmt->eventname, "sql_drop") == 0)
&& tags != NULL)
validate_ddl_tags("tag", tags);
else if (strcmp(stmt->eventname, "table_rewrite") == 0
&& tags != NULL)
validate_table_rewrite_tags("tag", tags);
/*
* Give user a nice error message if an event trigger of the same name
* already exists.
*/
tuple = SearchSysCache1(EVENTTRIGGERNAME, CStringGetDatum(stmt->trigname));
if (HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("event trigger \"%s\" already exists",
stmt->trigname)));
/* Find and validate the trigger function. */
funcoid = LookupFuncName(stmt->funcname, 0, fargtypes, false);
funcrettype = get_func_rettype(funcoid);
if (funcrettype != EVTTRIGGEROID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("function %s must return type %s",
NameListToString(stmt->funcname), "event_trigger")));
/* Insert catalog entries. */
return insert_event_trigger_tuple(stmt->trigname, stmt->eventname,
evtowner, funcoid, tags);
}
/*
* Validate DDL command tags.
*/
static void
validate_ddl_tags(const char *filtervar, List *taglist)
{
ListCell *lc;
foreach(lc, taglist)
{
const char *tag = strVal(lfirst(lc));
event_trigger_command_tag_check_result result;
result = check_ddl_tag(tag);
if (result == EVENT_TRIGGER_COMMAND_TAG_NOT_RECOGNIZED)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("filter value \"%s\" not recognized for filter variable \"%s\"",
tag, filtervar)));
if (result == EVENT_TRIGGER_COMMAND_TAG_NOT_SUPPORTED)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
/* translator: %s represents an SQL statement name */
errmsg("event triggers are not supported for %s",
tag)));
}
}
static event_trigger_command_tag_check_result
check_ddl_tag(const char *tag)
{
const char *obtypename;
event_trigger_support_data *etsd;
/*
* Handle some idiosyncratic special cases.
*/
if (pg_strcasecmp(tag, "CREATE TABLE AS") == 0 ||
pg_strcasecmp(tag, "SELECT INTO") == 0 ||
pg_strcasecmp(tag, "REFRESH MATERIALIZED VIEW") == 0 ||
pg_strcasecmp(tag, "ALTER DEFAULT PRIVILEGES") == 0 ||
pg_strcasecmp(tag, "ALTER LARGE OBJECT") == 0 ||
pg_strcasecmp(tag, "COMMENT") == 0 ||
pg_strcasecmp(tag, "GRANT") == 0 ||
pg_strcasecmp(tag, "REVOKE") == 0 ||
pg_strcasecmp(tag, "DROP OWNED") == 0 ||
pg_strcasecmp(tag, "IMPORT FOREIGN SCHEMA") == 0 ||
pg_strcasecmp(tag, "SECURITY LABEL") == 0)
return EVENT_TRIGGER_COMMAND_TAG_OK;
/*
* Otherwise, command should be CREATE, ALTER, or DROP.
*/
if (pg_strncasecmp(tag, "CREATE ", 7) == 0)
obtypename = tag + 7;
else if (pg_strncasecmp(tag, "ALTER ", 6) == 0)
obtypename = tag + 6;
else if (pg_strncasecmp(tag, "DROP ", 5) == 0)
obtypename = tag + 5;
else
return EVENT_TRIGGER_COMMAND_TAG_NOT_RECOGNIZED;
/*
* ...and the object type should be something recognizable.
*/
for (etsd = event_trigger_support; etsd->obtypename != NULL; etsd++)
if (pg_strcasecmp(etsd->obtypename, obtypename) == 0)
break;
if (etsd->obtypename == NULL)
return EVENT_TRIGGER_COMMAND_TAG_NOT_RECOGNIZED;
if (!etsd->supported)
return EVENT_TRIGGER_COMMAND_TAG_NOT_SUPPORTED;
return EVENT_TRIGGER_COMMAND_TAG_OK;
}
/*
* Validate DDL command tags for event table_rewrite.
*/
static void
validate_table_rewrite_tags(const char *filtervar, List *taglist)
{
ListCell *lc;
foreach(lc, taglist)
{
const char *tag = strVal(lfirst(lc));
event_trigger_command_tag_check_result result;
result = check_table_rewrite_ddl_tag(tag);
if (result == EVENT_TRIGGER_COMMAND_TAG_NOT_SUPPORTED)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
/* translator: %s represents an SQL statement name */
errmsg("event triggers are not supported for %s",
tag)));
}
}
static event_trigger_command_tag_check_result
check_table_rewrite_ddl_tag(const char *tag)
{
if (pg_strcasecmp(tag, "ALTER TABLE") == 0 ||
pg_strcasecmp(tag, "ALTER TYPE") == 0)
return EVENT_TRIGGER_COMMAND_TAG_OK;
return EVENT_TRIGGER_COMMAND_TAG_NOT_SUPPORTED;
}
/*
* Complain about a duplicate filter variable.
*/
static void
error_duplicate_filter_variable(const char *defname)
{
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("filter variable \"%s\" specified more than once",
defname)));
}
/*
* Insert the new pg_event_trigger row and record dependencies.
*/
static Oid
insert_event_trigger_tuple(const char *trigname, const char *eventname, Oid evtOwner,
Oid funcoid, List *taglist)
{
Relation tgrel;
Oid trigoid;
HeapTuple tuple;
Datum values[Natts_pg_trigger];
bool nulls[Natts_pg_trigger];
NameData evtnamedata,
evteventdata;
ObjectAddress myself,
referenced;
/* Open pg_event_trigger. */
tgrel = heap_open(EventTriggerRelationId, RowExclusiveLock);
/* Build the new pg_trigger tuple. */
memset(nulls, false, sizeof(nulls));
namestrcpy(&evtnamedata, trigname);
values[Anum_pg_event_trigger_evtname - 1] = NameGetDatum(&evtnamedata);
namestrcpy(&evteventdata, eventname);
values[Anum_pg_event_trigger_evtevent - 1] = NameGetDatum(&evteventdata);
values[Anum_pg_event_trigger_evtowner - 1] = ObjectIdGetDatum(evtOwner);
values[Anum_pg_event_trigger_evtfoid - 1] = ObjectIdGetDatum(funcoid);
values[Anum_pg_event_trigger_evtenabled - 1] =
CharGetDatum(TRIGGER_FIRES_ON_ORIGIN);
if (taglist == NIL)
nulls[Anum_pg_event_trigger_evttags - 1] = true;
else
values[Anum_pg_event_trigger_evttags - 1] =
filter_list_to_array(taglist);
/* Insert heap tuple. */
tuple = heap_form_tuple(tgrel->rd_att, values, nulls);
trigoid = CatalogTupleInsert(tgrel, tuple);
heap_freetuple(tuple);
/* Depend on owner. */
recordDependencyOnOwner(EventTriggerRelationId, trigoid, evtOwner);
/* Depend on event trigger function. */
myself.classId = EventTriggerRelationId;
myself.objectId = trigoid;
myself.objectSubId = 0;
referenced.classId = ProcedureRelationId;
referenced.objectId = funcoid;
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
/* Depend on extension, if any. */
recordDependencyOnCurrentExtension(&myself, false);
/* Post creation hook for new event trigger */
InvokeObjectPostCreateHook(EventTriggerRelationId, trigoid, 0);
/* Close pg_event_trigger. */
heap_close(tgrel, RowExclusiveLock);
return trigoid;
}
/*
* In the parser, a clause like WHEN tag IN ('cmd1', 'cmd2') is represented
* by a DefElem whose value is a List of String nodes; in the catalog, we
* store the list of strings as a text array. This function transforms the
* former representation into the latter one.
*
* For cleanliness, we store command tags in the catalog as text. It's
* possible (although not currently anticipated) that we might have
* a case-sensitive filter variable in the future, in which case this would
* need some further adjustment.
*/
static Datum
filter_list_to_array(List *filterlist)
{
ListCell *lc;
Datum *data;
int i = 0,
l = list_length(filterlist);
data = (Datum *) palloc(l * sizeof(Datum));
foreach(lc, filterlist)
{
const char *value = strVal(lfirst(lc));
char *result,
*p;
result = pstrdup(value);
for (p = result; *p; p++)
*p = pg_ascii_toupper((unsigned char) *p);
data[i++] = PointerGetDatum(cstring_to_text(result));
pfree(result);
}
return PointerGetDatum(construct_array(data, l, TEXTOID, -1, false, 'i'));
}
/*
* Guts of event trigger deletion.
*/
void
RemoveEventTriggerById(Oid trigOid)
{
Relation tgrel;
HeapTuple tup;
tgrel = heap_open(EventTriggerRelationId, RowExclusiveLock);
tup = SearchSysCache1(EVENTTRIGGEROID, ObjectIdGetDatum(trigOid));
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup failed for event trigger %u", trigOid);
CatalogTupleDelete(tgrel, &tup->t_self);
ReleaseSysCache(tup);
heap_close(tgrel, RowExclusiveLock);
}
/*
* ALTER EVENT TRIGGER foo ENABLE|DISABLE|ENABLE ALWAYS|REPLICA
*/
Oid
AlterEventTrigger(AlterEventTrigStmt *stmt)
{
Relation tgrel;
HeapTuple tup;
Oid trigoid;
Form_pg_event_trigger evtForm;
char tgenabled = stmt->tgenabled;
tgrel = heap_open(EventTriggerRelationId, RowExclusiveLock);
tup = SearchSysCacheCopy1(EVENTTRIGGERNAME,
CStringGetDatum(stmt->trigname));
if (!HeapTupleIsValid(tup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("event trigger \"%s\" does not exist",
stmt->trigname)));
trigoid = HeapTupleGetOid(tup);
if (!pg_event_trigger_ownercheck(trigoid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_EVENT_TRIGGER,
stmt->trigname);
/* tuple is a copy, so we can modify it below */
evtForm = (Form_pg_event_trigger) GETSTRUCT(tup);
evtForm->evtenabled = tgenabled;
CatalogTupleUpdate(tgrel, &tup->t_self, tup);
InvokeObjectPostAlterHook(EventTriggerRelationId,
trigoid, 0);
/* clean up */
heap_freetuple(tup);
heap_close(tgrel, RowExclusiveLock);
return trigoid;
}
/*
* Change event trigger's owner -- by name
*/
ObjectAddress
AlterEventTriggerOwner(const char *name, Oid newOwnerId)
{
Oid evtOid;
HeapTuple tup;
Relation rel;
ObjectAddress address;
rel = heap_open(EventTriggerRelationId, RowExclusiveLock);
tup = SearchSysCacheCopy1(EVENTTRIGGERNAME, CStringGetDatum(name));
if (!HeapTupleIsValid(tup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("event trigger \"%s\" does not exist", name)));
evtOid = HeapTupleGetOid(tup);
AlterEventTriggerOwner_internal(rel, tup, newOwnerId);
ObjectAddressSet(address, EventTriggerRelationId, evtOid);
heap_freetuple(tup);
heap_close(rel, RowExclusiveLock);
return address;
}
/*
* Change event trigger owner, by OID
*/
void
AlterEventTriggerOwner_oid(Oid trigOid, Oid newOwnerId)
{
HeapTuple tup;
Relation rel;
rel = heap_open(EventTriggerRelationId, RowExclusiveLock);
tup = SearchSysCacheCopy1(EVENTTRIGGEROID, ObjectIdGetDatum(trigOid));
if (!HeapTupleIsValid(tup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("event trigger with OID %u does not exist", trigOid)));
AlterEventTriggerOwner_internal(rel, tup, newOwnerId);
heap_freetuple(tup);
heap_close(rel, RowExclusiveLock);
}
/*
* Internal workhorse for changing an event trigger's owner
*/
static void
AlterEventTriggerOwner_internal(Relation rel, HeapTuple tup, Oid newOwnerId)
{
Form_pg_event_trigger form;
form = (Form_pg_event_trigger) GETSTRUCT(tup);
if (form->evtowner == newOwnerId)
return;
if (!pg_event_trigger_ownercheck(HeapTupleGetOid(tup), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_EVENT_TRIGGER,
NameStr(form->evtname));
/* New owner must be a superuser */
if (!superuser_arg(newOwnerId))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to change owner of event trigger \"%s\"",
NameStr(form->evtname)),
errhint("The owner of an event trigger must be a superuser.")));
form->evtowner = newOwnerId;
CatalogTupleUpdate(rel, &tup->t_self, tup);
/* Update owner dependency reference */
changeDependencyOnOwner(EventTriggerRelationId,
HeapTupleGetOid(tup),
newOwnerId);
InvokeObjectPostAlterHook(EventTriggerRelationId,
HeapTupleGetOid(tup), 0);
}
/*
* get_event_trigger_oid - Look up an event trigger by name to find its OID.
*
* If missing_ok is false, throw an error if trigger not found. If
* true, just return InvalidOid.
*/
Oid
get_event_trigger_oid(const char *trigname, bool missing_ok)
{
Oid oid;
oid = GetSysCacheOid1(EVENTTRIGGERNAME, CStringGetDatum(trigname));
if (!OidIsValid(oid) && !missing_ok)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("event trigger \"%s\" does not exist", trigname)));
return oid;
}
/*
* Return true when we want to fire given Event Trigger and false otherwise,
* filtering on the session replication role and the event trigger registered
* tags matching.
*/
static bool
filter_event_trigger(const char **tag, EventTriggerCacheItem *item)
{
/*
* Filter by session replication role, knowing that we never see disabled
* items down here.
*/
if (SessionReplicationRole == SESSION_REPLICATION_ROLE_REPLICA)
{
if (item->enabled == TRIGGER_FIRES_ON_ORIGIN)
return false;
}
else
{
if (item->enabled == TRIGGER_FIRES_ON_REPLICA)
return false;
}
/* Filter by tags, if any were specified. */
if (item->ntags != 0 && bsearch(tag, item->tag,
item->ntags, sizeof(char *),
pg_qsort_strcmp) == NULL)
return false;
/* if we reach that point, we're not filtering out this item */
return true;
}
/*
* Setup for running triggers for the given event. Return value is an OID list
* of functions to run; if there are any, trigdata is filled with an
* appropriate EventTriggerData for them to receive.
*/
static List *
EventTriggerCommonSetup(Node *parsetree,
EventTriggerEvent event, const char *eventstr,
EventTriggerData *trigdata)
{
const char *tag;
List *cachelist;
ListCell *lc;
List *runlist = NIL;
/*
* We want the list of command tags for which this procedure is actually
* invoked to match up exactly with the list that CREATE EVENT TRIGGER
* accepts. This debugging cross-check will throw an error if this
* function is invoked for a command tag that CREATE EVENT TRIGGER won't
* accept. (Unfortunately, there doesn't seem to be any simple, automated
* way to verify that CREATE EVENT TRIGGER doesn't accept extra stuff that
* never reaches this control point.)
*
* If this cross-check fails for you, you probably need to either adjust
* standard_ProcessUtility() not to invoke event triggers for the command
* type in question, or you need to adjust check_ddl_tag to accept the
* relevant command tag.
*/
#ifdef USE_ASSERT_CHECKING
{
const char *dbgtag;
dbgtag = CreateCommandTag(parsetree);
if (event == EVT_DDLCommandStart ||
event == EVT_DDLCommandEnd ||
event == EVT_SQLDrop)
{
if (check_ddl_tag(dbgtag) != EVENT_TRIGGER_COMMAND_TAG_OK)
elog(ERROR, "unexpected command tag \"%s\"", dbgtag);
}
else if (event == EVT_TableRewrite)
{
if (check_table_rewrite_ddl_tag(dbgtag) != EVENT_TRIGGER_COMMAND_TAG_OK)
elog(ERROR, "unexpected command tag \"%s\"", dbgtag);
}
}
#endif
/* Use cache to find triggers for this event; fast exit if none. */
cachelist = EventCacheLookup(event);
if (cachelist == NIL)
return NIL;
/* Get the command tag. */
tag = CreateCommandTag(parsetree);
/*
* Filter list of event triggers by command tag, and copy them into our
* memory context. Once we start running the command triggers, or indeed
* once we do anything at all that touches the catalogs, an invalidation
* might leave cachelist pointing at garbage, so we must do this before we
* can do much else.
*/
foreach(lc, cachelist)
{
EventTriggerCacheItem *item = lfirst(lc);
if (filter_event_trigger(&tag, item))
{
/* We must plan to fire this trigger. */
runlist = lappend_oid(runlist, item->fnoid);
}
}
/* don't spend any more time on this if no functions to run */
if (runlist == NIL)
return NIL;
trigdata->type = T_EventTriggerData;
trigdata->event = eventstr;
trigdata->parsetree = parsetree;
trigdata->tag = tag;
return runlist;
}
/*
* Fire ddl_command_start triggers.
*/
void
EventTriggerDDLCommandStart(Node *parsetree)
{
List *runlist;
EventTriggerData trigdata;
/*
* Event Triggers are completely disabled in standalone mode. There are
* (at least) two reasons for this:
*
* 1. A sufficiently broken event trigger might not only render the
* database unusable, but prevent disabling itself to fix the situation.
* In this scenario, restarting in standalone mode provides an escape
* hatch.
*
* 2. BuildEventTriggerCache relies on systable_beginscan_ordered, and
* therefore will malfunction if pg_event_trigger's indexes are damaged.
* To allow recovery from a damaged index, we need some operating mode
* wherein event triggers are disabled. (Or we could implement
* heapscan-and-sort logic for that case, but having disaster recovery
* scenarios depend on code that's otherwise untested isn't appetizing.)
*/
if (!IsUnderPostmaster)
return;
runlist = EventTriggerCommonSetup(parsetree,
EVT_DDLCommandStart,
"ddl_command_start",
&trigdata);
if (runlist == NIL)
return;
/* Run the triggers. */
EventTriggerInvoke(runlist, &trigdata);
/* Cleanup. */
list_free(runlist);
/*
* Make sure anything the event triggers did will be visible to the main
* command.
*/
CommandCounterIncrement();
}
/*
* Fire ddl_command_end triggers.
*/
void
EventTriggerDDLCommandEnd(Node *parsetree)
{
List *runlist;
EventTriggerData trigdata;
/*
* See EventTriggerDDLCommandStart for a discussion about why event
* triggers are disabled in single user mode.
*/
if (!IsUnderPostmaster)
return;
/*
* Also do nothing if our state isn't set up, which it won't be if there
* weren't any relevant event triggers at the start of the current DDL
* command. This test might therefore seem optional, but it's important
* because EventTriggerCommonSetup might find triggers that didn't exist
* at the time the command started. Although this function itself
* wouldn't crash, the event trigger functions would presumably call
* pg_event_trigger_ddl_commands which would fail. Better to do nothing
* until the next command.
*/
if (!currentEventTriggerState)
return;
runlist = EventTriggerCommonSetup(parsetree,
EVT_DDLCommandEnd, "ddl_command_end",
&trigdata);
if (runlist == NIL)
return;
/*
* Make sure anything the main command did will be visible to the event
* triggers.
*/
CommandCounterIncrement();
/* Run the triggers. */
EventTriggerInvoke(runlist, &trigdata);
/* Cleanup. */
list_free(runlist);
}
/*
* Fire sql_drop triggers.
*/
void
EventTriggerSQLDrop(Node *parsetree)
{
List *runlist;
EventTriggerData trigdata;
/*
* See EventTriggerDDLCommandStart for a discussion about why event
* triggers are disabled in single user mode.
*/
if (!IsUnderPostmaster)
return;
/*
* Use current state to determine whether this event fires at all. If
* there are no triggers for the sql_drop event, then we don't have
* anything to do here. Note that dropped object collection is disabled
* if this is the case, so even if we were to try to run, the list would
* be empty.
*/
if (!currentEventTriggerState ||
slist_is_empty(¤tEventTriggerState->SQLDropList))
return;
runlist = EventTriggerCommonSetup(parsetree,
EVT_SQLDrop, "sql_drop",
&trigdata);
/*
* Nothing to do if run list is empty. Note this typically can't happen,
* because if there are no sql_drop events, then objects-to-drop wouldn't
* have been collected in the first place and we would have quit above.
* But it could occur if event triggers were dropped partway through.
*/
if (runlist == NIL)
return;
/*
* Make sure anything the main command did will be visible to the event
* triggers.
*/
CommandCounterIncrement();
/*
* Make sure pg_event_trigger_dropped_objects only works when running
* these triggers. Use PG_TRY to ensure in_sql_drop is reset even when
* one trigger fails. (This is perhaps not necessary, as the currentState
* variable will be removed shortly by our caller, but it seems better to
* play safe.)
*/
currentEventTriggerState->in_sql_drop = true;
/* Run the triggers. */
PG_TRY();
{
EventTriggerInvoke(runlist, &trigdata);
}
PG_CATCH();
{
currentEventTriggerState->in_sql_drop = false;
PG_RE_THROW();
}
PG_END_TRY();
currentEventTriggerState->in_sql_drop = false;
/* Cleanup. */
list_free(runlist);
}
/*
* Fire table_rewrite triggers.
*/
void
EventTriggerTableRewrite(Node *parsetree, Oid tableOid, int reason)
{
List *runlist;
EventTriggerData trigdata;
/*
* Event Triggers are completely disabled in standalone mode. There are
* (at least) two reasons for this:
*
* 1. A sufficiently broken event trigger might not only render the
* database unusable, but prevent disabling itself to fix the situation.
* In this scenario, restarting in standalone mode provides an escape
* hatch.
*
* 2. BuildEventTriggerCache relies on systable_beginscan_ordered, and
* therefore will malfunction if pg_event_trigger's indexes are damaged.
* To allow recovery from a damaged index, we need some operating mode
* wherein event triggers are disabled. (Or we could implement
* heapscan-and-sort logic for that case, but having disaster recovery
* scenarios depend on code that's otherwise untested isn't appetizing.)
*/
if (!IsUnderPostmaster)
return;
/*
* Also do nothing if our state isn't set up, which it won't be if there
* weren't any relevant event triggers at the start of the current DDL
* command. This test might therefore seem optional, but it's
* *necessary*, because EventTriggerCommonSetup might find triggers that
* didn't exist at the time the command started.
*/
if (!currentEventTriggerState)
return;
runlist = EventTriggerCommonSetup(parsetree,
EVT_TableRewrite,
"table_rewrite",
&trigdata);
if (runlist == NIL)
return;
/*
* Make sure pg_event_trigger_table_rewrite_oid only works when running
* these triggers. Use PG_TRY to ensure table_rewrite_oid is reset even
* when one trigger fails. (This is perhaps not necessary, as the
* currentState variable will be removed shortly by our caller, but it
* seems better to play safe.)
*/
currentEventTriggerState->table_rewrite_oid = tableOid;
currentEventTriggerState->table_rewrite_reason = reason;
/* Run the triggers. */
PG_TRY();