/*------------------------------------------------------------------------- * * comment.c * * PostgreSQL object comments utility code. * * Copyright (c) 1996-2001, PostgreSQL Global Development Group * * IDENTIFICATION * $Header: /cvsroot/pgsql/src/backend/commands/comment.c,v 1.56 2002/08/09 16:45:14 tgl Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/genam.h" #include "access/heapam.h" #include "catalog/catname.h" #include "catalog/indexing.h" #include "catalog/namespace.h" #include "catalog/pg_constraint.h" #include "catalog/pg_description.h" #include "catalog/pg_operator.h" #include "catalog/pg_rewrite.h" #include "catalog/pg_trigger.h" #include "commands/comment.h" #include "commands/dbcommands.h" #include "miscadmin.h" #include "parser/parse_func.h" #include "parser/parse_oper.h" #include "parser/parse_type.h" #include "utils/acl.h" #include "utils/builtins.h" #include "utils/fmgroids.h" #include "utils/lsyscache.h" #include "utils/syscache.h" /* * Static Function Prototypes -- * * The following protoypes are declared static so as not to conflict * with any other routines outside this module. These routines are * called by the public function CommentObject() routine to create * the appropriate comment for the specific object type. */ static void CommentRelation(int objtype, List *relname, char *comment); static void CommentAttribute(List *qualname, char *comment); static void CommentDatabase(List *qualname, char *comment); static void CommentNamespace(List *qualname, char *comment); static void CommentRule(List *qualname, char *comment); static void CommentType(List *typename, char *comment); static void CommentAggregate(List *aggregate, List *arguments, char *comment); static void CommentProc(List *function, List *arguments, char *comment); static void CommentOperator(List *opername, List *arguments, char *comment); static void CommentTrigger(List *qualname, char *comment); static void CommentConstraint(List *qualname, char *comment); /* * CommentObject -- * * This routine is used to add the associated comment into * pg_description for the object specified by the given SQL command. */ void CommentObject(CommentStmt *stmt) { switch (stmt->objtype) { case COMMENT_ON_INDEX: case COMMENT_ON_SEQUENCE: case COMMENT_ON_TABLE: case COMMENT_ON_VIEW: CommentRelation(stmt->objtype, stmt->objname, stmt->comment); break; case COMMENT_ON_COLUMN: CommentAttribute(stmt->objname, stmt->comment); break; case COMMENT_ON_DATABASE: CommentDatabase(stmt->objname, stmt->comment); break; case COMMENT_ON_RULE: CommentRule(stmt->objname, stmt->comment); break; case COMMENT_ON_TYPE: CommentType(stmt->objname, stmt->comment); break; case COMMENT_ON_AGGREGATE: CommentAggregate(stmt->objname, stmt->objargs, stmt->comment); break; case COMMENT_ON_FUNCTION: CommentProc(stmt->objname, stmt->objargs, stmt->comment); break; case COMMENT_ON_OPERATOR: CommentOperator(stmt->objname, stmt->objargs, stmt->comment); break; case COMMENT_ON_TRIGGER: CommentTrigger(stmt->objname, stmt->comment); break; case COMMENT_ON_SCHEMA: CommentNamespace(stmt->objname, stmt->comment); break; case COMMENT_ON_CONSTRAINT: CommentConstraint(stmt->objname, stmt->comment); break; default: elog(ERROR, "An attempt was made to comment on a unknown type: %d", stmt->objtype); } } /* * CreateComments -- * * Create a comment for the specified object descriptor. Inserts a new * pg_description tuple, or replaces an existing one with the same key. * * If the comment given is null or an empty string, instead delete any * existing comment for the specified key. */ void CreateComments(Oid oid, Oid classoid, int32 subid, char *comment) { Relation description; ScanKeyData skey[3]; SysScanDesc sd; HeapTuple oldtuple; HeapTuple newtuple = NULL; Datum values[Natts_pg_description]; char nulls[Natts_pg_description]; char replaces[Natts_pg_description]; int i; /* Reduce empty-string to NULL case */ if (comment != NULL && strlen(comment) == 0) comment = NULL; /* Prepare to form or update a tuple, if necessary */ if (comment != NULL) { for (i = 0; i < Natts_pg_description; i++) { nulls[i] = ' '; replaces[i] = 'r'; } i = 0; values[i++] = ObjectIdGetDatum(oid); values[i++] = ObjectIdGetDatum(classoid); values[i++] = Int32GetDatum(subid); values[i++] = DirectFunctionCall1(textin, CStringGetDatum(comment)); } /* Use the index to search for a matching old tuple */ ScanKeyEntryInitialize(&skey[0], (bits16) 0x0, (AttrNumber) 1, (RegProcedure) F_OIDEQ, ObjectIdGetDatum(oid)); ScanKeyEntryInitialize(&skey[1], (bits16) 0x0, (AttrNumber) 2, (RegProcedure) F_OIDEQ, ObjectIdGetDatum(classoid)); ScanKeyEntryInitialize(&skey[2], (bits16) 0x0, (AttrNumber) 3, (RegProcedure) F_INT4EQ, Int32GetDatum(subid)); description = heap_openr(DescriptionRelationName, RowExclusiveLock); sd = systable_beginscan(description, DescriptionObjIndex, true, SnapshotNow, 3, skey); while ((oldtuple = systable_getnext(sd)) != NULL) { /* Found the old tuple, so delete or update it */ if (comment == NULL) simple_heap_delete(description, &oldtuple->t_self); else { newtuple = heap_modifytuple(oldtuple, description, values, nulls, replaces); simple_heap_update(description, &oldtuple->t_self, newtuple); } break; /* Assume there can be only one match */ } systable_endscan(sd); /* If we didn't find an old tuple, insert a new one */ if (newtuple == NULL && comment != NULL) { newtuple = heap_formtuple(RelationGetDescr(description), values, nulls); simple_heap_insert(description, newtuple); } /* Update indexes, if necessary */ if (newtuple != NULL) { CatalogUpdateIndexes(description, newtuple); heap_freetuple(newtuple); } /* Done */ heap_close(description, NoLock); } /* * DeleteComments -- remove comments for an object * * If subid is nonzero then only comments matching it will be removed. * If subid is zero, all comments matching the oid/classoid will be removed * (this corresponds to deleting a whole object). */ void DeleteComments(Oid oid, Oid classoid, int32 subid) { Relation description; ScanKeyData skey[3]; int nkeys; SysScanDesc sd; HeapTuple oldtuple; /* Use the index to search for all matching old tuples */ ScanKeyEntryInitialize(&skey[0], 0x0, Anum_pg_description_objoid, F_OIDEQ, ObjectIdGetDatum(oid)); ScanKeyEntryInitialize(&skey[1], 0x0, Anum_pg_description_classoid, F_OIDEQ, ObjectIdGetDatum(classoid)); if (subid != 0) { ScanKeyEntryInitialize(&skey[2], 0x0, Anum_pg_description_objsubid, F_INT4EQ, Int32GetDatum(subid)); nkeys = 3; } else nkeys = 2; description = heap_openr(DescriptionRelationName, RowExclusiveLock); sd = systable_beginscan(description, DescriptionObjIndex, true, SnapshotNow, nkeys, skey); while ((oldtuple = systable_getnext(sd)) != NULL) { simple_heap_delete(description, &oldtuple->t_self); } /* Done */ systable_endscan(sd); heap_close(description, RowExclusiveLock); } /* * CommentRelation -- * * This routine is used to add/drop a comment from a relation, where * a relation is a TABLE, SEQUENCE, VIEW or INDEX. The routine simply * finds the relation name by searching the system cache, locating * the appropriate tuple, and inserting a comment using that * tuple's oid. Its parameters are the relation name and comments. */ static void CommentRelation(int objtype, List *relname, char *comment) { Relation relation; RangeVar *tgtrel; tgtrel = makeRangeVarFromNameList(relname); /* * Open the relation. We do this mainly to acquire a lock that * ensures no one else drops the relation before we commit. (If they * did, they'd fail to remove the entry we are about to make in * pg_description.) */ relation = relation_openrv(tgtrel, AccessShareLock); /* Check object security */ if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(relation)); /* Next, verify that the relation type matches the intent */ switch (objtype) { case COMMENT_ON_INDEX: if (relation->rd_rel->relkind != RELKIND_INDEX) elog(ERROR, "relation \"%s\" is not an index", RelationGetRelationName(relation)); break; case COMMENT_ON_SEQUENCE: if (relation->rd_rel->relkind != RELKIND_SEQUENCE) elog(ERROR, "relation \"%s\" is not a sequence", RelationGetRelationName(relation)); break; case COMMENT_ON_TABLE: if (relation->rd_rel->relkind != RELKIND_RELATION) elog(ERROR, "relation \"%s\" is not a table", RelationGetRelationName(relation)); break; case COMMENT_ON_VIEW: if (relation->rd_rel->relkind != RELKIND_VIEW) elog(ERROR, "relation \"%s\" is not a view", RelationGetRelationName(relation)); break; } /* Create the comment using the relation's oid */ CreateComments(RelationGetRelid(relation), RelOid_pg_class, 0, comment); /* Done, but hold lock until commit */ relation_close(relation, NoLock); } /* * CommentAttribute -- * * This routine is used to add/drop a comment from an attribute * such as a table's column. The routine will check security * restrictions and then attempt to look up the specified * attribute. If successful, a comment is added/dropped, else an * elog() exception is thrown. The parameters are the relation * and attribute names, and the comments */ static void CommentAttribute(List *qualname, char *comment) { int nnames; List *relname; char *attrname; RangeVar *rel; Relation relation; AttrNumber attnum; /* Separate relname and attr name */ nnames = length(qualname); if (nnames < 2) elog(ERROR, "CommentAttribute: must specify relation.attribute"); relname = ltruncate(nnames-1, listCopy(qualname)); attrname = strVal(nth(nnames-1, qualname)); /* Open the containing relation to ensure it won't go away meanwhile */ rel = makeRangeVarFromNameList(relname); relation = heap_openrv(rel, AccessShareLock); /* Check object security */ if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(relation)); /* Now, fetch the attribute number from the system cache */ attnum = get_attnum(RelationGetRelid(relation), attrname); if (attnum == InvalidAttrNumber) elog(ERROR, "Relation \"%s\" has no column \"%s\"", RelationGetRelationName(relation), attrname); /* Create the comment using the relation's oid */ CreateComments(RelationGetRelid(relation), RelOid_pg_class, (int32) attnum, comment); /* Done, but hold lock until commit */ heap_close(relation, NoLock); } /* * CommentDatabase -- * * This routine is used to add/drop any user-comments a user might * have regarding the specified database. The routine will check * security for owner permissions, and, if succesful, will then * attempt to find the oid of the database specified. Once found, * a comment is added/dropped using the CreateComments() routine. */ static void CommentDatabase(List *qualname, char *comment) { char *database; Oid oid; if (length(qualname) != 1) elog(ERROR, "CommentDatabase: database name may not be qualified"); database = strVal(lfirst(qualname)); /* First get the database OID */ oid = get_database_oid(database); if (!OidIsValid(oid)) elog(ERROR, "database \"%s\" does not exist", database); /* Allow if the user matches the database dba or is a superuser */ if (!(superuser() || is_dbadmin(oid))) elog(ERROR, "you are not permitted to comment on database \"%s\"", database); /* Only allow comments on the current database */ if (oid != MyDatabaseId) elog(ERROR, "Database comments may only be applied to the current database"); /* Create the comment with the pg_database oid */ CreateComments(oid, RelOid_pg_database, 0, comment); } /* * CommentNamespace -- * * This routine is used to add/drop any user-comments a user might * have regarding the specified namespace. The routine will check * security for owner permissions, and, if succesful, will then * attempt to find the oid of the namespace specified. Once found, * a comment is added/dropped using the CreateComments() routine. */ static void CommentNamespace(List *qualname, char *comment) { Oid oid; Oid classoid; char *namespace; if (length(qualname) != 1) elog(ERROR, "CommentSchema: schema name may not be qualified"); namespace = strVal(lfirst(qualname)); oid = GetSysCacheOid(NAMESPACENAME, CStringGetDatum(namespace), 0, 0, 0); if (!OidIsValid(oid)) elog(ERROR, "CommentSchema: Schema \"%s\" could not be found", namespace); /* Check object security */ if (!pg_namespace_ownercheck(oid, GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, namespace); /* pg_namespace doesn't have a hard-coded OID, so must look it up */ classoid = get_system_catalog_relid(NamespaceRelationName); /* Call CreateComments() to create/drop the comments */ CreateComments(oid, classoid, 0, comment); } /* * CommentRule -- * * This routine is used to add/drop any user-comments a user might * have regarding a specified RULE. The rule for commenting is determined by * both its name and the relation to which it refers. The arguments to this * function are the rule name and relation name (merged into a qualified * name), and the comment to add/drop. * * Before PG 7.3, rules had unique names across the whole database, and so * the syntax was just COMMENT ON RULE rulename, with no relation name. * For purposes of backwards compatibility, we support that as long as there * is only one rule by the specified name in the database. */ static void CommentRule(List *qualname, char *comment) { int nnames; List *relname; char *rulename; RangeVar *rel; Relation relation; HeapTuple tuple; Oid reloid; Oid ruleoid; Oid classoid; AclResult aclcheck; /* Separate relname and trig name */ nnames = length(qualname); if (nnames == 1) { /* Old-style: only a rule name is given */ Relation RewriteRelation; HeapScanDesc scanDesc; ScanKeyData scanKeyData; rulename = strVal(lfirst(qualname)); /* Search pg_rewrite for such a rule */ ScanKeyEntryInitialize(&scanKeyData, 0, Anum_pg_rewrite_rulename, F_NAMEEQ, PointerGetDatum(rulename)); RewriteRelation = heap_openr(RewriteRelationName, AccessShareLock); scanDesc = heap_beginscan(RewriteRelation, SnapshotNow, 1, &scanKeyData); tuple = heap_getnext(scanDesc, ForwardScanDirection); if (HeapTupleIsValid(tuple)) { reloid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class; AssertTupleDescHasOid(RewriteRelation->rd_att); ruleoid = HeapTupleGetOid(tuple); } else { elog(ERROR, "rule \"%s\" does not exist", rulename); reloid = ruleoid = 0; /* keep compiler quiet */ } if (HeapTupleIsValid(tuple = heap_getnext(scanDesc, ForwardScanDirection))) elog(ERROR, "There are multiple rules \"%s\"" "\n\tPlease specify a relation name as well as a rule name", rulename); heap_endscan(scanDesc); heap_close(RewriteRelation, AccessShareLock); /* Open the owning relation to ensure it won't go away meanwhile */ relation = heap_open(reloid, AccessShareLock); } else { /* New-style: rule and relname both provided */ Assert(nnames >= 2); relname = ltruncate(nnames-1, listCopy(qualname)); rulename = strVal(nth(nnames-1, qualname)); /* Open the owning relation to ensure it won't go away meanwhile */ rel = makeRangeVarFromNameList(relname); relation = heap_openrv(rel, AccessShareLock); reloid = RelationGetRelid(relation); /* Find the rule's pg_rewrite tuple, get its OID */ tuple = SearchSysCache(RULERELNAME, ObjectIdGetDatum(reloid), PointerGetDatum(rulename), 0, 0); if (!HeapTupleIsValid(tuple)) elog(ERROR, "rule \"%s\" does not exist", rulename); Assert(reloid == ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class); AssertTupleDescHasOid(relation->rd_att); ruleoid = HeapTupleGetOid(tuple); ReleaseSysCache(tuple); } /* Check object security */ aclcheck = pg_class_aclcheck(reloid, GetUserId(), ACL_RULE); if (aclcheck != ACLCHECK_OK) aclcheck_error(aclcheck, rulename); /* pg_rewrite doesn't have a hard-coded OID, so must look it up */ classoid = get_system_catalog_relid(RewriteRelationName); /* Call CreateComments() to create/drop the comments */ CreateComments(ruleoid, classoid, 0, comment); } /* * CommentType -- * * This routine is used to add/drop any user-comments a user might * have regarding a TYPE. The type is specified by name * and, if found, and the user has appropriate permissions, a * comment will be added/dropped using the CreateComments() routine. * The type's name and the comments are the paramters to this routine. */ static void CommentType(List *typename, char *comment) { TypeName *tname; Oid oid; /* XXX a bit of a crock; should accept TypeName in COMMENT syntax */ tname = makeNode(TypeName); tname->names = typename; tname->typmod = -1; /* Find the type's oid */ oid = typenameTypeId(tname); /* Check object security */ if (!pg_type_ownercheck(oid, GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, TypeNameToString(tname)); /* Call CreateComments() to create/drop the comments */ CreateComments(oid, RelOid_pg_type, 0, comment); } /* * CommentAggregate -- * * This routine is used to allow a user to provide comments on an * aggregate function. The aggregate function is determined by both * its name and its argument type, which, with the comments are * the three parameters handed to this routine. */ static void CommentAggregate(List *aggregate, List *arguments, char *comment) { TypeName *aggtype = (TypeName *) lfirst(arguments); Oid baseoid, oid; /* First, attempt to determine the base aggregate oid */ if (aggtype) baseoid = typenameTypeId(aggtype); else baseoid = InvalidOid; /* Now, attempt to find the actual tuple in pg_proc */ oid = find_aggregate_func("CommentAggregate", aggregate, baseoid); /* Next, validate the user's attempt to comment */ if (!pg_proc_ownercheck(oid, GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, NameListToString(aggregate)); /* Call CreateComments() to create/drop the comments */ CreateComments(oid, RelOid_pg_proc, 0, comment); } /* * CommentProc -- * * This routine is used to allow a user to provide comments on an * procedure (function). The procedure is determined by both * its name and its argument list. The argument list is expected to * be a series of parsed nodes pointed to by a List object. If the * comments string is empty, the associated comment is dropped. */ static void CommentProc(List *function, List *arguments, char *comment) { Oid oid; /* Look up the procedure */ oid = LookupFuncNameTypeNames(function, arguments, true, "CommentProc"); /* Now, validate the user's ability to comment on this function */ if (!pg_proc_ownercheck(oid, GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, NameListToString(function)); /* Call CreateComments() to create/drop the comments */ CreateComments(oid, RelOid_pg_proc, 0, comment); } /* * CommentOperator -- * * This routine is used to allow a user to provide comments on an * operator. The operator for commenting is determined by both * its name and its argument list which defines the left and right * hand types the operator will operate on. The argument list is * expected to be a couple of parse nodes pointed to be a List * object. */ static void CommentOperator(List *opername, List *arguments, char *comment) { TypeName *typenode1 = (TypeName *) lfirst(arguments); TypeName *typenode2 = (TypeName *) lsecond(arguments); Oid oid; Oid classoid; /* Look up the operator */ oid = LookupOperNameTypeNames(opername, typenode1, typenode2, "CommentOperator"); /* Valid user's ability to comment on this operator */ if (!pg_oper_ownercheck(oid, GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, NameListToString(opername)); /* pg_operator doesn't have a hard-coded OID, so must look it up */ classoid = get_system_catalog_relid(OperatorRelationName); /* Call CreateComments() to create/drop the comments */ CreateComments(oid, classoid, 0, comment); } /* * CommentTrigger -- * * This routine is used to allow a user to provide comments on a * trigger event. The trigger for commenting is determined by both * its name and the relation to which it refers. The arguments to this * function are the trigger name and relation name (merged into a qualified * name), and the comment to add/drop. */ static void CommentTrigger(List *qualname, char *comment) { int nnames; List *relname; char *trigname; RangeVar *rel; Relation pg_trigger, relation; HeapTuple triggertuple; SysScanDesc scan; ScanKeyData entry[2]; Oid oid; /* Separate relname and trig name */ nnames = length(qualname); if (nnames < 2) elog(ERROR, "CommentTrigger: must specify relation and trigger"); relname = ltruncate(nnames-1, listCopy(qualname)); trigname = strVal(nth(nnames-1, qualname)); /* Open the owning relation to ensure it won't go away meanwhile */ rel = makeRangeVarFromNameList(relname); relation = heap_openrv(rel, AccessShareLock); /* Check object security */ if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(relation)); /* * Fetch the trigger tuple from pg_trigger. There can be only one * because of the unique index. */ pg_trigger = heap_openr(TriggerRelationName, AccessShareLock); ScanKeyEntryInitialize(&entry[0], 0x0, Anum_pg_trigger_tgrelid, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(relation))); ScanKeyEntryInitialize(&entry[1], 0x0, Anum_pg_trigger_tgname, F_NAMEEQ, CStringGetDatum(trigname)); scan = systable_beginscan(pg_trigger, TriggerRelidNameIndex, true, SnapshotNow, 2, entry); triggertuple = systable_getnext(scan); /* If no trigger exists for the relation specified, notify user */ if (!HeapTupleIsValid(triggertuple)) elog(ERROR, "trigger \"%s\" for relation \"%s\" does not exist", trigname, RelationGetRelationName(relation)); AssertTupleDescHasOid(pg_trigger->rd_att); oid = HeapTupleGetOid(triggertuple); systable_endscan(scan); /* Create the comment with the pg_trigger oid */ CreateComments(oid, RelationGetRelid(pg_trigger), 0, comment); /* Done, but hold lock on relation */ heap_close(pg_trigger, AccessShareLock); heap_close(relation, NoLock); } /* * CommentConstraint -- * * Enable commenting on constraints held within the pg_constraint * table. A qualified name is required as constraint names are * unique per relation. */ static void CommentConstraint(List *qualname, char *comment) { int nnames; List *relName; char *conName; RangeVar *rel; Relation pg_constraint, relation; HeapTuple tuple; SysScanDesc scan; ScanKeyData skey[1]; Oid conOid = InvalidOid; /* Separate relname and constraint name */ nnames = length(qualname); if (nnames < 2) elog(ERROR, "CommentConstraint: must specify relation and constraint"); relName = ltruncate(nnames-1, listCopy(qualname)); conName = strVal(nth(nnames-1, qualname)); /* Open the owning relation to ensure it won't go away meanwhile */ rel = makeRangeVarFromNameList(relName); relation = heap_openrv(rel, AccessShareLock); /* Check object security */ if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(relation)); /* * Fetch the constraint tuple from pg_constraint. There may be more than * one match, because constraints are not required to have unique names; * if so, error out. */ pg_constraint = heap_openr(ConstraintRelationName, AccessShareLock); ScanKeyEntryInitialize(&skey[0], 0x0, Anum_pg_constraint_conrelid, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(relation))); scan = systable_beginscan(pg_constraint, ConstraintRelidIndex, true, SnapshotNow, 1, skey); while (HeapTupleIsValid(tuple = systable_getnext(scan))) { Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tuple); if (strcmp(NameStr(con->conname), conName) == 0) { if (OidIsValid(conOid)) elog(ERROR, "Relation \"%s\" has multiple constraints named \"%s\"", RelationGetRelationName(relation), conName); conOid = HeapTupleGetOid(tuple); } } systable_endscan(scan); /* If no constraint exists for the relation specified, notify user */ if (!OidIsValid(conOid)) elog(ERROR, "constraint \"%s\" for relation \"%s\" does not exist", conName, RelationGetRelationName(relation)); /* Create the comment with the pg_constraint oid */ CreateComments(conOid, RelationGetRelid(pg_constraint), 0, comment); /* Done, but hold lock on relation */ heap_close(pg_constraint, AccessShareLock); heap_close(relation, NoLock); }