1 /*-------------------------------------------------------------------------
2  *
3  * pg_shdepend.c
4  *	  routines to support manipulation of the pg_shdepend relation
5  *
6  * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
7  * Portions Copyright (c) 1994, Regents of the University of California
8  *
9  *
10  * IDENTIFICATION
11  *	  src/backend/catalog/pg_shdepend.c
12  *
13  *-------------------------------------------------------------------------
14  */
15 #include "postgres.h"
16 
17 #include "access/genam.h"
18 #include "access/htup_details.h"
19 #include "access/table.h"
20 #include "access/xact.h"
21 #include "catalog/catalog.h"
22 #include "catalog/dependency.h"
23 #include "catalog/indexing.h"
24 #include "catalog/pg_authid.h"
25 #include "catalog/pg_collation.h"
26 #include "catalog/pg_conversion.h"
27 #include "catalog/pg_database.h"
28 #include "catalog/pg_default_acl.h"
29 #include "catalog/pg_event_trigger.h"
30 #include "catalog/pg_extension.h"
31 #include "catalog/pg_foreign_data_wrapper.h"
32 #include "catalog/pg_foreign_server.h"
33 #include "catalog/pg_language.h"
34 #include "catalog/pg_largeobject.h"
35 #include "catalog/pg_largeobject_metadata.h"
36 #include "catalog/pg_namespace.h"
37 #include "catalog/pg_opclass.h"
38 #include "catalog/pg_operator.h"
39 #include "catalog/pg_opfamily.h"
40 #include "catalog/pg_proc.h"
41 #include "catalog/pg_shdepend.h"
42 #include "catalog/pg_statistic_ext.h"
43 #include "catalog/pg_subscription.h"
44 #include "catalog/pg_tablespace.h"
45 #include "catalog/pg_ts_config.h"
46 #include "catalog/pg_ts_dict.h"
47 #include "catalog/pg_type.h"
48 #include "catalog/pg_user_mapping.h"
49 #include "commands/alter.h"
50 #include "commands/collationcmds.h"
51 #include "commands/conversioncmds.h"
52 #include "commands/dbcommands.h"
53 #include "commands/defrem.h"
54 #include "commands/event_trigger.h"
55 #include "commands/extension.h"
56 #include "commands/policy.h"
57 #include "commands/proclang.h"
58 #include "commands/publicationcmds.h"
59 #include "commands/schemacmds.h"
60 #include "commands/subscriptioncmds.h"
61 #include "commands/tablecmds.h"
62 #include "commands/tablespace.h"
63 #include "commands/typecmds.h"
64 #include "miscadmin.h"
65 #include "storage/lmgr.h"
66 #include "utils/acl.h"
67 #include "utils/fmgroids.h"
68 #include "utils/syscache.h"
69 
70 typedef enum
71 {
72 	LOCAL_OBJECT,
73 	SHARED_OBJECT,
74 	REMOTE_OBJECT
75 } SharedDependencyObjectType;
76 
77 typedef struct
78 {
79 	ObjectAddress object;
80 	char		deptype;
81 	SharedDependencyObjectType objtype;
82 } ShDependObjectInfo;
83 
84 static void getOidListDiff(Oid *list1, int *nlist1, Oid *list2, int *nlist2);
85 static Oid	classIdGetDbId(Oid classId);
86 static void shdepChangeDep(Relation sdepRel,
87 						   Oid classid, Oid objid, int32 objsubid,
88 						   Oid refclassid, Oid refobjid,
89 						   SharedDependencyType deptype);
90 static void shdepAddDependency(Relation sdepRel,
91 							   Oid classId, Oid objectId, int32 objsubId,
92 							   Oid refclassId, Oid refobjId,
93 							   SharedDependencyType deptype);
94 static void shdepDropDependency(Relation sdepRel,
95 								Oid classId, Oid objectId, int32 objsubId,
96 								bool drop_subobjects,
97 								Oid refclassId, Oid refobjId,
98 								SharedDependencyType deptype);
99 static void storeObjectDescription(StringInfo descs,
100 								   SharedDependencyObjectType type,
101 								   ObjectAddress *object,
102 								   SharedDependencyType deptype,
103 								   int count);
104 static bool isSharedObjectPinned(Oid classId, Oid objectId, Relation sdepRel);
105 
106 
107 /*
108  * recordSharedDependencyOn
109  *
110  * Record a dependency between 2 objects via their respective ObjectAddresses.
111  * The first argument is the dependent object, the second the one it
112  * references (which must be a shared object).
113  *
114  * This locks the referenced object and makes sure it still exists.
115  * Then it creates an entry in pg_shdepend.  The lock is kept until
116  * the end of the transaction.
117  *
118  * Dependencies on pinned objects are not recorded.
119  */
120 void
recordSharedDependencyOn(ObjectAddress * depender,ObjectAddress * referenced,SharedDependencyType deptype)121 recordSharedDependencyOn(ObjectAddress *depender,
122 						 ObjectAddress *referenced,
123 						 SharedDependencyType deptype)
124 {
125 	Relation	sdepRel;
126 
127 	/*
128 	 * Objects in pg_shdepend can't have SubIds.
129 	 */
130 	Assert(depender->objectSubId == 0);
131 	Assert(referenced->objectSubId == 0);
132 
133 	/*
134 	 * During bootstrap, do nothing since pg_shdepend may not exist yet.
135 	 * initdb will fill in appropriate pg_shdepend entries after bootstrap.
136 	 */
137 	if (IsBootstrapProcessingMode())
138 		return;
139 
140 	sdepRel = table_open(SharedDependRelationId, RowExclusiveLock);
141 
142 	/* If the referenced object is pinned, do nothing. */
143 	if (!isSharedObjectPinned(referenced->classId, referenced->objectId,
144 							  sdepRel))
145 	{
146 		shdepAddDependency(sdepRel, depender->classId, depender->objectId,
147 						   depender->objectSubId,
148 						   referenced->classId, referenced->objectId,
149 						   deptype);
150 	}
151 
152 	table_close(sdepRel, RowExclusiveLock);
153 }
154 
155 /*
156  * recordDependencyOnOwner
157  *
158  * A convenient wrapper of recordSharedDependencyOn -- register the specified
159  * user as owner of the given object.
160  *
161  * Note: it's the caller's responsibility to ensure that there isn't an owner
162  * entry for the object already.
163  */
164 void
recordDependencyOnOwner(Oid classId,Oid objectId,Oid owner)165 recordDependencyOnOwner(Oid classId, Oid objectId, Oid owner)
166 {
167 	ObjectAddress myself,
168 				referenced;
169 
170 	myself.classId = classId;
171 	myself.objectId = objectId;
172 	myself.objectSubId = 0;
173 
174 	referenced.classId = AuthIdRelationId;
175 	referenced.objectId = owner;
176 	referenced.objectSubId = 0;
177 
178 	recordSharedDependencyOn(&myself, &referenced, SHARED_DEPENDENCY_OWNER);
179 }
180 
181 /*
182  * shdepChangeDep
183  *
184  * Update shared dependency records to account for an updated referenced
185  * object.  This is an internal workhorse for operations such as changing
186  * an object's owner.
187  *
188  * There must be no more than one existing entry for the given dependent
189  * object and dependency type!	So in practice this can only be used for
190  * updating SHARED_DEPENDENCY_OWNER and SHARED_DEPENDENCY_TABLESPACE
191  * entries, which should have that property.
192  *
193  * If there is no previous entry, we assume it was referencing a PINned
194  * object, so we create a new entry.  If the new referenced object is
195  * PINned, we don't create an entry (and drop the old one, if any).
196  * (For tablespaces, we don't record dependencies in certain cases, so
197  * there are other possible reasons for entries to be missing.)
198  *
199  * sdepRel must be the pg_shdepend relation, already opened and suitably
200  * locked.
201  */
202 static void
shdepChangeDep(Relation sdepRel,Oid classid,Oid objid,int32 objsubid,Oid refclassid,Oid refobjid,SharedDependencyType deptype)203 shdepChangeDep(Relation sdepRel,
204 			   Oid classid, Oid objid, int32 objsubid,
205 			   Oid refclassid, Oid refobjid,
206 			   SharedDependencyType deptype)
207 {
208 	Oid			dbid = classIdGetDbId(classid);
209 	HeapTuple	oldtup = NULL;
210 	HeapTuple	scantup;
211 	ScanKeyData key[4];
212 	SysScanDesc scan;
213 
214 	/*
215 	 * Make sure the new referenced object doesn't go away while we record the
216 	 * dependency.
217 	 */
218 	shdepLockAndCheckObject(refclassid, refobjid);
219 
220 	/*
221 	 * Look for a previous entry
222 	 */
223 	ScanKeyInit(&key[0],
224 				Anum_pg_shdepend_dbid,
225 				BTEqualStrategyNumber, F_OIDEQ,
226 				ObjectIdGetDatum(dbid));
227 	ScanKeyInit(&key[1],
228 				Anum_pg_shdepend_classid,
229 				BTEqualStrategyNumber, F_OIDEQ,
230 				ObjectIdGetDatum(classid));
231 	ScanKeyInit(&key[2],
232 				Anum_pg_shdepend_objid,
233 				BTEqualStrategyNumber, F_OIDEQ,
234 				ObjectIdGetDatum(objid));
235 	ScanKeyInit(&key[3],
236 				Anum_pg_shdepend_objsubid,
237 				BTEqualStrategyNumber, F_INT4EQ,
238 				Int32GetDatum(objsubid));
239 
240 	scan = systable_beginscan(sdepRel, SharedDependDependerIndexId, true,
241 							  NULL, 4, key);
242 
243 	while ((scantup = systable_getnext(scan)) != NULL)
244 	{
245 		/* Ignore if not of the target dependency type */
246 		if (((Form_pg_shdepend) GETSTRUCT(scantup))->deptype != deptype)
247 			continue;
248 		/* Caller screwed up if multiple matches */
249 		if (oldtup)
250 			elog(ERROR,
251 				 "multiple pg_shdepend entries for object %u/%u/%d deptype %c",
252 				 classid, objid, objsubid, deptype);
253 		oldtup = heap_copytuple(scantup);
254 	}
255 
256 	systable_endscan(scan);
257 
258 	if (isSharedObjectPinned(refclassid, refobjid, sdepRel))
259 	{
260 		/* No new entry needed, so just delete existing entry if any */
261 		if (oldtup)
262 			CatalogTupleDelete(sdepRel, &oldtup->t_self);
263 	}
264 	else if (oldtup)
265 	{
266 		/* Need to update existing entry */
267 		Form_pg_shdepend shForm = (Form_pg_shdepend) GETSTRUCT(oldtup);
268 
269 		/* Since oldtup is a copy, we can just modify it in-memory */
270 		shForm->refclassid = refclassid;
271 		shForm->refobjid = refobjid;
272 
273 		CatalogTupleUpdate(sdepRel, &oldtup->t_self, oldtup);
274 	}
275 	else
276 	{
277 		/* Need to insert new entry */
278 		Datum		values[Natts_pg_shdepend];
279 		bool		nulls[Natts_pg_shdepend];
280 
281 		memset(nulls, false, sizeof(nulls));
282 
283 		values[Anum_pg_shdepend_dbid - 1] = ObjectIdGetDatum(dbid);
284 		values[Anum_pg_shdepend_classid - 1] = ObjectIdGetDatum(classid);
285 		values[Anum_pg_shdepend_objid - 1] = ObjectIdGetDatum(objid);
286 		values[Anum_pg_shdepend_objsubid - 1] = Int32GetDatum(objsubid);
287 
288 		values[Anum_pg_shdepend_refclassid - 1] = ObjectIdGetDatum(refclassid);
289 		values[Anum_pg_shdepend_refobjid - 1] = ObjectIdGetDatum(refobjid);
290 		values[Anum_pg_shdepend_deptype - 1] = CharGetDatum(deptype);
291 
292 		/*
293 		 * we are reusing oldtup just to avoid declaring a new variable, but
294 		 * it's certainly a new tuple
295 		 */
296 		oldtup = heap_form_tuple(RelationGetDescr(sdepRel), values, nulls);
297 		CatalogTupleInsert(sdepRel, oldtup);
298 	}
299 
300 	if (oldtup)
301 		heap_freetuple(oldtup);
302 }
303 
304 /*
305  * changeDependencyOnOwner
306  *
307  * Update the shared dependencies to account for the new owner.
308  *
309  * Note: we don't need an objsubid argument because only whole objects
310  * have owners.
311  */
312 void
changeDependencyOnOwner(Oid classId,Oid objectId,Oid newOwnerId)313 changeDependencyOnOwner(Oid classId, Oid objectId, Oid newOwnerId)
314 {
315 	Relation	sdepRel;
316 
317 	sdepRel = table_open(SharedDependRelationId, RowExclusiveLock);
318 
319 	/* Adjust the SHARED_DEPENDENCY_OWNER entry */
320 	shdepChangeDep(sdepRel,
321 				   classId, objectId, 0,
322 				   AuthIdRelationId, newOwnerId,
323 				   SHARED_DEPENDENCY_OWNER);
324 
325 	/*----------
326 	 * There should never be a SHARED_DEPENDENCY_ACL entry for the owner,
327 	 * so get rid of it if there is one.  This can happen if the new owner
328 	 * was previously granted some rights to the object.
329 	 *
330 	 * This step is analogous to aclnewowner's removal of duplicate entries
331 	 * in the ACL.  We have to do it to handle this scenario:
332 	 *		A grants some rights on an object to B
333 	 *		ALTER OWNER changes the object's owner to B
334 	 *		ALTER OWNER changes the object's owner to C
335 	 * The third step would remove all mention of B from the object's ACL,
336 	 * but we'd still have a SHARED_DEPENDENCY_ACL for B if we did not do
337 	 * things this way.
338 	 *
339 	 * The rule against having a SHARED_DEPENDENCY_ACL entry for the owner
340 	 * allows us to fix things up in just this one place, without having
341 	 * to make the various ALTER OWNER routines each know about it.
342 	 *----------
343 	 */
344 	shdepDropDependency(sdepRel, classId, objectId, 0, true,
345 						AuthIdRelationId, newOwnerId,
346 						SHARED_DEPENDENCY_ACL);
347 
348 	table_close(sdepRel, RowExclusiveLock);
349 }
350 
351 /*
352  * recordDependencyOnTablespace
353  *
354  * A convenient wrapper of recordSharedDependencyOn -- register the specified
355  * tablespace as default for the given object.
356  *
357  * Note: it's the caller's responsibility to ensure that there isn't a
358  * tablespace entry for the object already.
359  */
360 void
recordDependencyOnTablespace(Oid classId,Oid objectId,Oid tablespace)361 recordDependencyOnTablespace(Oid classId, Oid objectId, Oid tablespace)
362 {
363 	ObjectAddress myself,
364 				  referenced;
365 
366 	ObjectAddressSet(myself, classId, objectId);
367 	ObjectAddressSet(referenced, TableSpaceRelationId, tablespace);
368 
369 	recordSharedDependencyOn(&myself, &referenced,
370 							 SHARED_DEPENDENCY_TABLESPACE);
371 }
372 
373 /*
374  * changeDependencyOnTablespace
375  *
376  * Update the shared dependencies to account for the new tablespace.
377  *
378  * Note: we don't need an objsubid argument because only whole objects
379  * have tablespaces.
380  */
381 void
changeDependencyOnTablespace(Oid classId,Oid objectId,Oid newTablespaceId)382 changeDependencyOnTablespace(Oid classId, Oid objectId, Oid newTablespaceId)
383 {
384 	Relation	sdepRel;
385 
386 	sdepRel = table_open(SharedDependRelationId, RowExclusiveLock);
387 
388 	if (newTablespaceId != DEFAULTTABLESPACE_OID &&
389 		newTablespaceId != InvalidOid)
390 		shdepChangeDep(sdepRel,
391 					   classId, objectId, 0,
392 					   TableSpaceRelationId, newTablespaceId,
393 					   SHARED_DEPENDENCY_TABLESPACE);
394 	else
395 		shdepDropDependency(sdepRel,
396 							classId, objectId, 0, true,
397 							InvalidOid, InvalidOid,
398 							SHARED_DEPENDENCY_INVALID);
399 
400 	table_close(sdepRel, RowExclusiveLock);
401 }
402 
403 /*
404  * getOidListDiff
405  *		Helper for updateAclDependencies.
406  *
407  * Takes two Oid arrays and removes elements that are common to both arrays,
408  * leaving just those that are in one input but not the other.
409  * We assume both arrays have been sorted and de-duped.
410  */
411 static void
getOidListDiff(Oid * list1,int * nlist1,Oid * list2,int * nlist2)412 getOidListDiff(Oid *list1, int *nlist1, Oid *list2, int *nlist2)
413 {
414 	int			in1,
415 				in2,
416 				out1,
417 				out2;
418 
419 	in1 = in2 = out1 = out2 = 0;
420 	while (in1 < *nlist1 && in2 < *nlist2)
421 	{
422 		if (list1[in1] == list2[in2])
423 		{
424 			/* skip over duplicates */
425 			in1++;
426 			in2++;
427 		}
428 		else if (list1[in1] < list2[in2])
429 		{
430 			/* list1[in1] is not in list2 */
431 			list1[out1++] = list1[in1++];
432 		}
433 		else
434 		{
435 			/* list2[in2] is not in list1 */
436 			list2[out2++] = list2[in2++];
437 		}
438 	}
439 
440 	/* any remaining list1 entries are not in list2 */
441 	while (in1 < *nlist1)
442 	{
443 		list1[out1++] = list1[in1++];
444 	}
445 
446 	/* any remaining list2 entries are not in list1 */
447 	while (in2 < *nlist2)
448 	{
449 		list2[out2++] = list2[in2++];
450 	}
451 
452 	*nlist1 = out1;
453 	*nlist2 = out2;
454 }
455 
456 /*
457  * updateAclDependencies
458  *		Update the pg_shdepend info for an object's ACL during GRANT/REVOKE.
459  *
460  * classId, objectId, objsubId: identify the object whose ACL this is
461  * ownerId: role owning the object
462  * noldmembers, oldmembers: array of roleids appearing in old ACL
463  * nnewmembers, newmembers: array of roleids appearing in new ACL
464  *
465  * We calculate the differences between the new and old lists of roles,
466  * and then insert or delete from pg_shdepend as appropriate.
467  *
468  * Note that we can't just insert all referenced roles blindly during GRANT,
469  * because we would end up with duplicate registered dependencies.  We could
470  * check for existence of the tuples before inserting, but that seems to be
471  * more expensive than what we are doing here.  Likewise we can't just delete
472  * blindly during REVOKE, because the user may still have other privileges.
473  * It is also possible that REVOKE actually adds dependencies, due to
474  * instantiation of a formerly implicit default ACL (although at present,
475  * all such dependencies should be for the owning role, which we ignore here).
476  *
477  * NOTE: Both input arrays must be sorted and de-duped.  (Typically they
478  * are extracted from an ACL array by aclmembers(), which takes care of
479  * both requirements.)	The arrays are pfreed before return.
480  */
481 void
updateAclDependencies(Oid classId,Oid objectId,int32 objsubId,Oid ownerId,int noldmembers,Oid * oldmembers,int nnewmembers,Oid * newmembers)482 updateAclDependencies(Oid classId, Oid objectId, int32 objsubId,
483 					  Oid ownerId,
484 					  int noldmembers, Oid *oldmembers,
485 					  int nnewmembers, Oid *newmembers)
486 {
487 	Relation	sdepRel;
488 	int			i;
489 
490 	/*
491 	 * Remove entries that are common to both lists; those represent existing
492 	 * dependencies we don't need to change.
493 	 *
494 	 * OK to overwrite the inputs since we'll pfree them anyway.
495 	 */
496 	getOidListDiff(oldmembers, &noldmembers, newmembers, &nnewmembers);
497 
498 	if (noldmembers > 0 || nnewmembers > 0)
499 	{
500 		sdepRel = table_open(SharedDependRelationId, RowExclusiveLock);
501 
502 		/* Add new dependencies that weren't already present */
503 		for (i = 0; i < nnewmembers; i++)
504 		{
505 			Oid			roleid = newmembers[i];
506 
507 			/*
508 			 * Skip the owner: he has an OWNER shdep entry instead. (This is
509 			 * not just a space optimization; it makes ALTER OWNER easier. See
510 			 * notes in changeDependencyOnOwner.)
511 			 */
512 			if (roleid == ownerId)
513 				continue;
514 
515 			/* Skip pinned roles; they don't need dependency entries */
516 			if (isSharedObjectPinned(AuthIdRelationId, roleid, sdepRel))
517 				continue;
518 
519 			shdepAddDependency(sdepRel, classId, objectId, objsubId,
520 							   AuthIdRelationId, roleid,
521 							   SHARED_DEPENDENCY_ACL);
522 		}
523 
524 		/* Drop no-longer-used old dependencies */
525 		for (i = 0; i < noldmembers; i++)
526 		{
527 			Oid			roleid = oldmembers[i];
528 
529 			/* Skip the owner, same as above */
530 			if (roleid == ownerId)
531 				continue;
532 
533 			/* Skip pinned roles */
534 			if (isSharedObjectPinned(AuthIdRelationId, roleid, sdepRel))
535 				continue;
536 
537 			shdepDropDependency(sdepRel, classId, objectId, objsubId,
538 								false,	/* exact match on objsubId */
539 								AuthIdRelationId, roleid,
540 								SHARED_DEPENDENCY_ACL);
541 		}
542 
543 		table_close(sdepRel, RowExclusiveLock);
544 	}
545 
546 	if (oldmembers)
547 		pfree(oldmembers);
548 	if (newmembers)
549 		pfree(newmembers);
550 }
551 
552 /*
553  * A struct to keep track of dependencies found in other databases.
554  */
555 typedef struct
556 {
557 	Oid			dbOid;
558 	int			count;
559 } remoteDep;
560 
561 /*
562  * qsort comparator for ShDependObjectInfo items
563  */
564 static int
shared_dependency_comparator(const void * a,const void * b)565 shared_dependency_comparator(const void *a, const void *b)
566 {
567 	const ShDependObjectInfo *obja = (const ShDependObjectInfo *) a;
568 	const ShDependObjectInfo *objb = (const ShDependObjectInfo *) b;
569 
570 	/*
571 	 * Primary sort key is OID ascending.
572 	 */
573 	if (obja->object.objectId < objb->object.objectId)
574 		return -1;
575 	if (obja->object.objectId > objb->object.objectId)
576 		return 1;
577 
578 	/*
579 	 * Next sort on catalog ID, in case identical OIDs appear in different
580 	 * catalogs.  Sort direction is pretty arbitrary here.
581 	 */
582 	if (obja->object.classId < objb->object.classId)
583 		return -1;
584 	if (obja->object.classId > objb->object.classId)
585 		return 1;
586 
587 	/*
588 	 * Sort on object subId.
589 	 *
590 	 * We sort the subId as an unsigned int so that 0 (the whole object) will
591 	 * come first.
592 	 */
593 	if ((unsigned int) obja->object.objectSubId < (unsigned int) objb->object.objectSubId)
594 		return -1;
595 	if ((unsigned int) obja->object.objectSubId > (unsigned int) objb->object.objectSubId)
596 		return 1;
597 
598 	/*
599 	 * Last, sort on deptype, in case the same object has multiple dependency
600 	 * types.  (Note that there's no need to consider objtype, as that's
601 	 * determined by the catalog OID.)
602 	 */
603 	if (obja->deptype < objb->deptype)
604 		return -1;
605 	if (obja->deptype > objb->deptype)
606 		return 1;
607 
608 	return 0;
609 }
610 
611 /*
612  * checkSharedDependencies
613  *
614  * Check whether there are shared dependency entries for a given shared
615  * object; return true if so.
616  *
617  * In addition, return a string containing a newline-separated list of object
618  * descriptions that depend on the shared object, or NULL if none is found.
619  * We actually return two such strings; the "detail" result is suitable for
620  * returning to the client as an errdetail() string, and is limited in size.
621  * The "detail_log" string is potentially much longer, and should be emitted
622  * to the server log only.
623  *
624  * We can find three different kinds of dependencies: dependencies on objects
625  * of the current database; dependencies on shared objects; and dependencies
626  * on objects local to other databases.  We can (and do) provide descriptions
627  * of the two former kinds of objects, but we can't do that for "remote"
628  * objects, so we just provide a count of them.
629  *
630  * If we find a SHARED_DEPENDENCY_PIN entry, we can error out early.
631  */
632 bool
checkSharedDependencies(Oid classId,Oid objectId,char ** detail_msg,char ** detail_log_msg)633 checkSharedDependencies(Oid classId, Oid objectId,
634 						char **detail_msg, char **detail_log_msg)
635 {
636 	Relation	sdepRel;
637 	ScanKeyData key[2];
638 	SysScanDesc scan;
639 	HeapTuple	tup;
640 	int			numReportedDeps = 0;
641 	int			numNotReportedDeps = 0;
642 	int			numNotReportedDbs = 0;
643 	List	   *remDeps = NIL;
644 	ListCell   *cell;
645 	ObjectAddress object;
646 	ShDependObjectInfo *objects;
647 	int			numobjects;
648 	int			allocedobjects;
649 	StringInfoData descs;
650 	StringInfoData alldescs;
651 
652 	/*
653 	 * We limit the number of dependencies reported to the client to
654 	 * MAX_REPORTED_DEPS, since client software may not deal well with
655 	 * enormous error strings.  The server log always gets a full report.
656 	 *
657 	 * For stability of regression test results, we sort local and shared
658 	 * objects by OID before reporting them.  We don't worry about the order
659 	 * in which other databases are reported, though.
660 	 */
661 #define MAX_REPORTED_DEPS 100
662 
663 	allocedobjects = 128;		/* arbitrary initial array size */
664 	objects = (ShDependObjectInfo *)
665 		palloc(allocedobjects * sizeof(ShDependObjectInfo));
666 	numobjects = 0;
667 	initStringInfo(&descs);
668 	initStringInfo(&alldescs);
669 
670 	sdepRel = table_open(SharedDependRelationId, AccessShareLock);
671 
672 	ScanKeyInit(&key[0],
673 				Anum_pg_shdepend_refclassid,
674 				BTEqualStrategyNumber, F_OIDEQ,
675 				ObjectIdGetDatum(classId));
676 	ScanKeyInit(&key[1],
677 				Anum_pg_shdepend_refobjid,
678 				BTEqualStrategyNumber, F_OIDEQ,
679 				ObjectIdGetDatum(objectId));
680 
681 	scan = systable_beginscan(sdepRel, SharedDependReferenceIndexId, true,
682 							  NULL, 2, key);
683 
684 	while (HeapTupleIsValid(tup = systable_getnext(scan)))
685 	{
686 		Form_pg_shdepend sdepForm = (Form_pg_shdepend) GETSTRUCT(tup);
687 
688 		/* This case can be dispatched quickly */
689 		if (sdepForm->deptype == SHARED_DEPENDENCY_PIN)
690 		{
691 			object.classId = classId;
692 			object.objectId = objectId;
693 			object.objectSubId = 0;
694 			ereport(ERROR,
695 					(errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
696 					 errmsg("cannot drop %s because it is required by the database system",
697 							getObjectDescription(&object))));
698 		}
699 
700 		object.classId = sdepForm->classid;
701 		object.objectId = sdepForm->objid;
702 		object.objectSubId = sdepForm->objsubid;
703 
704 		/*
705 		 * If it's a dependency local to this database or it's a shared
706 		 * object, add it to the objects array.
707 		 *
708 		 * If it's a remote dependency, keep track of it so we can report the
709 		 * number of them later.
710 		 */
711 		if (sdepForm->dbid == MyDatabaseId ||
712 			sdepForm->dbid == InvalidOid)
713 		{
714 			if (numobjects >= allocedobjects)
715 			{
716 				allocedobjects *= 2;
717 				objects = (ShDependObjectInfo *)
718 					repalloc(objects,
719 							 allocedobjects * sizeof(ShDependObjectInfo));
720 			}
721 			objects[numobjects].object = object;
722 			objects[numobjects].deptype = sdepForm->deptype;
723 			objects[numobjects].objtype = (sdepForm->dbid == MyDatabaseId) ?
724 				LOCAL_OBJECT : SHARED_OBJECT;
725 			numobjects++;
726 		}
727 		else
728 		{
729 			/* It's not local nor shared, so it must be remote. */
730 			remoteDep  *dep;
731 			bool		stored = false;
732 
733 			/*
734 			 * XXX this info is kept on a simple List.  Maybe it's not good
735 			 * for performance, but using a hash table seems needlessly
736 			 * complex.  The expected number of databases is not high anyway,
737 			 * I suppose.
738 			 */
739 			foreach(cell, remDeps)
740 			{
741 				dep = lfirst(cell);
742 				if (dep->dbOid == sdepForm->dbid)
743 				{
744 					dep->count++;
745 					stored = true;
746 					break;
747 				}
748 			}
749 			if (!stored)
750 			{
751 				dep = (remoteDep *) palloc(sizeof(remoteDep));
752 				dep->dbOid = sdepForm->dbid;
753 				dep->count = 1;
754 				remDeps = lappend(remDeps, dep);
755 			}
756 		}
757 	}
758 
759 	systable_endscan(scan);
760 
761 	table_close(sdepRel, AccessShareLock);
762 
763 	/*
764 	 * Sort and report local and shared objects.
765 	 */
766 	if (numobjects > 1)
767 		qsort((void *) objects, numobjects,
768 			  sizeof(ShDependObjectInfo), shared_dependency_comparator);
769 
770 	for (int i = 0; i < numobjects; i++)
771 	{
772 		if (numReportedDeps < MAX_REPORTED_DEPS)
773 		{
774 			numReportedDeps++;
775 			storeObjectDescription(&descs,
776 								   objects[i].objtype,
777 								   &objects[i].object,
778 								   objects[i].deptype,
779 								   0);
780 		}
781 		else
782 			numNotReportedDeps++;
783 		storeObjectDescription(&alldescs,
784 							   objects[i].objtype,
785 							   &objects[i].object,
786 							   objects[i].deptype,
787 							   0);
788 	}
789 
790 	/*
791 	 * Summarize dependencies in remote databases.
792 	 */
793 	foreach(cell, remDeps)
794 	{
795 		remoteDep  *dep = lfirst(cell);
796 
797 		object.classId = DatabaseRelationId;
798 		object.objectId = dep->dbOid;
799 		object.objectSubId = 0;
800 
801 		if (numReportedDeps < MAX_REPORTED_DEPS)
802 		{
803 			numReportedDeps++;
804 			storeObjectDescription(&descs, REMOTE_OBJECT, &object,
805 								   SHARED_DEPENDENCY_INVALID, dep->count);
806 		}
807 		else
808 			numNotReportedDbs++;
809 		storeObjectDescription(&alldescs, REMOTE_OBJECT, &object,
810 							   SHARED_DEPENDENCY_INVALID, dep->count);
811 	}
812 
813 	pfree(objects);
814 	list_free_deep(remDeps);
815 
816 	if (descs.len == 0)
817 	{
818 		pfree(descs.data);
819 		pfree(alldescs.data);
820 		*detail_msg = *detail_log_msg = NULL;
821 		return false;
822 	}
823 
824 	if (numNotReportedDeps > 0)
825 		appendStringInfo(&descs, ngettext("\nand %d other object "
826 										  "(see server log for list)",
827 										  "\nand %d other objects "
828 										  "(see server log for list)",
829 										  numNotReportedDeps),
830 						 numNotReportedDeps);
831 	if (numNotReportedDbs > 0)
832 		appendStringInfo(&descs, ngettext("\nand objects in %d other database "
833 										  "(see server log for list)",
834 										  "\nand objects in %d other databases "
835 										  "(see server log for list)",
836 										  numNotReportedDbs),
837 						 numNotReportedDbs);
838 
839 	*detail_msg = descs.data;
840 	*detail_log_msg = alldescs.data;
841 	return true;
842 }
843 
844 /*
845  * copyTemplateDependencies
846  *
847  * Routine to create the initial shared dependencies of a new database.
848  * We simply copy the dependencies from the template database.
849  */
850 void
copyTemplateDependencies(Oid templateDbId,Oid newDbId)851 copyTemplateDependencies(Oid templateDbId, Oid newDbId)
852 {
853 	Relation	sdepRel;
854 	TupleDesc	sdepDesc;
855 	ScanKeyData key[1];
856 	SysScanDesc scan;
857 	HeapTuple	tup;
858 	CatalogIndexState indstate;
859 	Datum		values[Natts_pg_shdepend];
860 	bool		nulls[Natts_pg_shdepend];
861 	bool		replace[Natts_pg_shdepend];
862 
863 	sdepRel = table_open(SharedDependRelationId, RowExclusiveLock);
864 	sdepDesc = RelationGetDescr(sdepRel);
865 
866 	indstate = CatalogOpenIndexes(sdepRel);
867 
868 	/* Scan all entries with dbid = templateDbId */
869 	ScanKeyInit(&key[0],
870 				Anum_pg_shdepend_dbid,
871 				BTEqualStrategyNumber, F_OIDEQ,
872 				ObjectIdGetDatum(templateDbId));
873 
874 	scan = systable_beginscan(sdepRel, SharedDependDependerIndexId, true,
875 							  NULL, 1, key);
876 
877 	/* Set up to copy the tuples except for inserting newDbId */
878 	memset(values, 0, sizeof(values));
879 	memset(nulls, false, sizeof(nulls));
880 	memset(replace, false, sizeof(replace));
881 
882 	replace[Anum_pg_shdepend_dbid - 1] = true;
883 	values[Anum_pg_shdepend_dbid - 1] = ObjectIdGetDatum(newDbId);
884 
885 	/*
886 	 * Copy the entries of the original database, changing the database Id to
887 	 * that of the new database.  Note that because we are not copying rows
888 	 * with dbId == 0 (ie, rows describing dependent shared objects) we won't
889 	 * copy the ownership dependency of the template database itself; this is
890 	 * what we want.
891 	 */
892 	while (HeapTupleIsValid(tup = systable_getnext(scan)))
893 	{
894 		HeapTuple	newtup;
895 
896 		newtup = heap_modify_tuple(tup, sdepDesc, values, nulls, replace);
897 		CatalogTupleInsertWithInfo(sdepRel, newtup, indstate);
898 
899 		heap_freetuple(newtup);
900 	}
901 
902 	systable_endscan(scan);
903 
904 	CatalogCloseIndexes(indstate);
905 	table_close(sdepRel, RowExclusiveLock);
906 }
907 
908 /*
909  * dropDatabaseDependencies
910  *
911  * Delete pg_shdepend entries corresponding to a database that's being
912  * dropped.
913  */
914 void
dropDatabaseDependencies(Oid databaseId)915 dropDatabaseDependencies(Oid databaseId)
916 {
917 	Relation	sdepRel;
918 	ScanKeyData key[1];
919 	SysScanDesc scan;
920 	HeapTuple	tup;
921 
922 	sdepRel = table_open(SharedDependRelationId, RowExclusiveLock);
923 
924 	/*
925 	 * First, delete all the entries that have the database Oid in the dbid
926 	 * field.
927 	 */
928 	ScanKeyInit(&key[0],
929 				Anum_pg_shdepend_dbid,
930 				BTEqualStrategyNumber, F_OIDEQ,
931 				ObjectIdGetDatum(databaseId));
932 	/* We leave the other index fields unspecified */
933 
934 	scan = systable_beginscan(sdepRel, SharedDependDependerIndexId, true,
935 							  NULL, 1, key);
936 
937 	while (HeapTupleIsValid(tup = systable_getnext(scan)))
938 	{
939 		CatalogTupleDelete(sdepRel, &tup->t_self);
940 	}
941 
942 	systable_endscan(scan);
943 
944 	/* Now delete all entries corresponding to the database itself */
945 	shdepDropDependency(sdepRel, DatabaseRelationId, databaseId, 0, true,
946 						InvalidOid, InvalidOid,
947 						SHARED_DEPENDENCY_INVALID);
948 
949 	table_close(sdepRel, RowExclusiveLock);
950 }
951 
952 /*
953  * deleteSharedDependencyRecordsFor
954  *
955  * Delete all pg_shdepend entries corresponding to an object that's being
956  * dropped or modified.  The object is assumed to be either a shared object
957  * or local to the current database (the classId tells us which).
958  *
959  * If objectSubId is zero, we are deleting a whole object, so get rid of
960  * pg_shdepend entries for subobjects as well.
961  */
962 void
deleteSharedDependencyRecordsFor(Oid classId,Oid objectId,int32 objectSubId)963 deleteSharedDependencyRecordsFor(Oid classId, Oid objectId, int32 objectSubId)
964 {
965 	Relation	sdepRel;
966 
967 	sdepRel = table_open(SharedDependRelationId, RowExclusiveLock);
968 
969 	shdepDropDependency(sdepRel, classId, objectId, objectSubId,
970 						(objectSubId == 0),
971 						InvalidOid, InvalidOid,
972 						SHARED_DEPENDENCY_INVALID);
973 
974 	table_close(sdepRel, RowExclusiveLock);
975 }
976 
977 /*
978  * shdepAddDependency
979  *		Internal workhorse for inserting into pg_shdepend
980  *
981  * sdepRel must be the pg_shdepend relation, already opened and suitably
982  * locked.
983  */
984 static void
shdepAddDependency(Relation sdepRel,Oid classId,Oid objectId,int32 objsubId,Oid refclassId,Oid refobjId,SharedDependencyType deptype)985 shdepAddDependency(Relation sdepRel,
986 				   Oid classId, Oid objectId, int32 objsubId,
987 				   Oid refclassId, Oid refobjId,
988 				   SharedDependencyType deptype)
989 {
990 	HeapTuple	tup;
991 	Datum		values[Natts_pg_shdepend];
992 	bool		nulls[Natts_pg_shdepend];
993 
994 	/*
995 	 * Make sure the object doesn't go away while we record the dependency on
996 	 * it.  DROP routines should lock the object exclusively before they check
997 	 * shared dependencies.
998 	 */
999 	shdepLockAndCheckObject(refclassId, refobjId);
1000 
1001 	memset(nulls, false, sizeof(nulls));
1002 
1003 	/*
1004 	 * Form the new tuple and record the dependency.
1005 	 */
1006 	values[Anum_pg_shdepend_dbid - 1] = ObjectIdGetDatum(classIdGetDbId(classId));
1007 	values[Anum_pg_shdepend_classid - 1] = ObjectIdGetDatum(classId);
1008 	values[Anum_pg_shdepend_objid - 1] = ObjectIdGetDatum(objectId);
1009 	values[Anum_pg_shdepend_objsubid - 1] = Int32GetDatum(objsubId);
1010 
1011 	values[Anum_pg_shdepend_refclassid - 1] = ObjectIdGetDatum(refclassId);
1012 	values[Anum_pg_shdepend_refobjid - 1] = ObjectIdGetDatum(refobjId);
1013 	values[Anum_pg_shdepend_deptype - 1] = CharGetDatum(deptype);
1014 
1015 	tup = heap_form_tuple(sdepRel->rd_att, values, nulls);
1016 
1017 	CatalogTupleInsert(sdepRel, tup);
1018 
1019 	/* clean up */
1020 	heap_freetuple(tup);
1021 }
1022 
1023 /*
1024  * shdepDropDependency
1025  *		Internal workhorse for deleting entries from pg_shdepend.
1026  *
1027  * We drop entries having the following properties:
1028  *	dependent object is the one identified by classId/objectId/objsubId
1029  *	if refclassId isn't InvalidOid, it must match the entry's refclassid
1030  *	if refobjId isn't InvalidOid, it must match the entry's refobjid
1031  *	if deptype isn't SHARED_DEPENDENCY_INVALID, it must match entry's deptype
1032  *
1033  * If drop_subobjects is true, we ignore objsubId and consider all entries
1034  * matching classId/objectId.
1035  *
1036  * sdepRel must be the pg_shdepend relation, already opened and suitably
1037  * locked.
1038  */
1039 static void
shdepDropDependency(Relation sdepRel,Oid classId,Oid objectId,int32 objsubId,bool drop_subobjects,Oid refclassId,Oid refobjId,SharedDependencyType deptype)1040 shdepDropDependency(Relation sdepRel,
1041 					Oid classId, Oid objectId, int32 objsubId,
1042 					bool drop_subobjects,
1043 					Oid refclassId, Oid refobjId,
1044 					SharedDependencyType deptype)
1045 {
1046 	ScanKeyData key[4];
1047 	int			nkeys;
1048 	SysScanDesc scan;
1049 	HeapTuple	tup;
1050 
1051 	/* Scan for entries matching the dependent object */
1052 	ScanKeyInit(&key[0],
1053 				Anum_pg_shdepend_dbid,
1054 				BTEqualStrategyNumber, F_OIDEQ,
1055 				ObjectIdGetDatum(classIdGetDbId(classId)));
1056 	ScanKeyInit(&key[1],
1057 				Anum_pg_shdepend_classid,
1058 				BTEqualStrategyNumber, F_OIDEQ,
1059 				ObjectIdGetDatum(classId));
1060 	ScanKeyInit(&key[2],
1061 				Anum_pg_shdepend_objid,
1062 				BTEqualStrategyNumber, F_OIDEQ,
1063 				ObjectIdGetDatum(objectId));
1064 	if (drop_subobjects)
1065 		nkeys = 3;
1066 	else
1067 	{
1068 		ScanKeyInit(&key[3],
1069 					Anum_pg_shdepend_objsubid,
1070 					BTEqualStrategyNumber, F_INT4EQ,
1071 					Int32GetDatum(objsubId));
1072 		nkeys = 4;
1073 	}
1074 
1075 	scan = systable_beginscan(sdepRel, SharedDependDependerIndexId, true,
1076 							  NULL, nkeys, key);
1077 
1078 	while (HeapTupleIsValid(tup = systable_getnext(scan)))
1079 	{
1080 		Form_pg_shdepend shdepForm = (Form_pg_shdepend) GETSTRUCT(tup);
1081 
1082 		/* Filter entries according to additional parameters */
1083 		if (OidIsValid(refclassId) && shdepForm->refclassid != refclassId)
1084 			continue;
1085 		if (OidIsValid(refobjId) && shdepForm->refobjid != refobjId)
1086 			continue;
1087 		if (deptype != SHARED_DEPENDENCY_INVALID &&
1088 			shdepForm->deptype != deptype)
1089 			continue;
1090 
1091 		/* OK, delete it */
1092 		CatalogTupleDelete(sdepRel, &tup->t_self);
1093 	}
1094 
1095 	systable_endscan(scan);
1096 }
1097 
1098 /*
1099  * classIdGetDbId
1100  *
1101  * Get the database Id that should be used in pg_shdepend, given the OID
1102  * of the catalog containing the object.  For shared objects, it's 0
1103  * (InvalidOid); for all other objects, it's the current database Id.
1104  */
1105 static Oid
classIdGetDbId(Oid classId)1106 classIdGetDbId(Oid classId)
1107 {
1108 	Oid			dbId;
1109 
1110 	if (IsSharedRelation(classId))
1111 		dbId = InvalidOid;
1112 	else
1113 		dbId = MyDatabaseId;
1114 
1115 	return dbId;
1116 }
1117 
1118 /*
1119  * shdepLockAndCheckObject
1120  *
1121  * Lock the object that we are about to record a dependency on.
1122  * After it's locked, verify that it hasn't been dropped while we
1123  * weren't looking.  If the object has been dropped, this function
1124  * does not return!
1125  */
1126 void
shdepLockAndCheckObject(Oid classId,Oid objectId)1127 shdepLockAndCheckObject(Oid classId, Oid objectId)
1128 {
1129 	/* AccessShareLock should be OK, since we are not modifying the object */
1130 	LockSharedObject(classId, objectId, 0, AccessShareLock);
1131 
1132 	switch (classId)
1133 	{
1134 		case AuthIdRelationId:
1135 			if (!SearchSysCacheExists1(AUTHOID, ObjectIdGetDatum(objectId)))
1136 				ereport(ERROR,
1137 						(errcode(ERRCODE_UNDEFINED_OBJECT),
1138 						 errmsg("role %u was concurrently dropped",
1139 								objectId)));
1140 			break;
1141 
1142 		case TableSpaceRelationId:
1143 			{
1144 				/* For lack of a syscache on pg_tablespace, do this: */
1145 				char	   *tablespace = get_tablespace_name(objectId);
1146 
1147 				if (tablespace == NULL)
1148 					ereport(ERROR,
1149 							(errcode(ERRCODE_UNDEFINED_OBJECT),
1150 							 errmsg("tablespace %u was concurrently dropped",
1151 									objectId)));
1152 				pfree(tablespace);
1153 				break;
1154 			}
1155 
1156 		case DatabaseRelationId:
1157 			{
1158 				/* For lack of a syscache on pg_database, do this: */
1159 				char	   *database = get_database_name(objectId);
1160 
1161 				if (database == NULL)
1162 					ereport(ERROR,
1163 							(errcode(ERRCODE_UNDEFINED_OBJECT),
1164 							 errmsg("database %u was concurrently dropped",
1165 									objectId)));
1166 				pfree(database);
1167 				break;
1168 			}
1169 
1170 
1171 		default:
1172 			elog(ERROR, "unrecognized shared classId: %u", classId);
1173 	}
1174 }
1175 
1176 
1177 /*
1178  * storeObjectDescription
1179  *		Append the description of a dependent object to "descs"
1180  *
1181  * While searching for dependencies of a shared object, we stash the
1182  * descriptions of dependent objects we find in a single string, which we
1183  * later pass to ereport() in the DETAIL field when somebody attempts to
1184  * drop a referenced shared object.
1185  *
1186  * When type is LOCAL_OBJECT or SHARED_OBJECT, we expect object to be the
1187  * dependent object, deptype is the dependency type, and count is not used.
1188  * When type is REMOTE_OBJECT, we expect object to be the database object,
1189  * and count to be nonzero; deptype is not used in this case.
1190  */
1191 static void
storeObjectDescription(StringInfo descs,SharedDependencyObjectType type,ObjectAddress * object,SharedDependencyType deptype,int count)1192 storeObjectDescription(StringInfo descs,
1193 					   SharedDependencyObjectType type,
1194 					   ObjectAddress *object,
1195 					   SharedDependencyType deptype,
1196 					   int count)
1197 {
1198 	char	   *objdesc = getObjectDescription(object);
1199 
1200 	/*
1201 	 * An object being dropped concurrently doesn't need to be reported.
1202 	 */
1203 	if (objdesc == NULL)
1204 		return;
1205 
1206 	/* separate entries with a newline */
1207 	if (descs->len != 0)
1208 		appendStringInfoChar(descs, '\n');
1209 
1210 	switch (type)
1211 	{
1212 		case LOCAL_OBJECT:
1213 		case SHARED_OBJECT:
1214 			if (deptype == SHARED_DEPENDENCY_OWNER)
1215 				appendStringInfo(descs, _("owner of %s"), objdesc);
1216 			else if (deptype == SHARED_DEPENDENCY_ACL)
1217 				appendStringInfo(descs, _("privileges for %s"), objdesc);
1218 			else if (deptype == SHARED_DEPENDENCY_POLICY)
1219 				appendStringInfo(descs, _("target of %s"), objdesc);
1220 			else if (deptype == SHARED_DEPENDENCY_TABLESPACE)
1221 				appendStringInfo(descs, _("tablespace for %s"), objdesc);
1222 			else
1223 				elog(ERROR, "unrecognized dependency type: %d",
1224 					 (int) deptype);
1225 			break;
1226 
1227 		case REMOTE_OBJECT:
1228 			/* translator: %s will always be "database %s" */
1229 			appendStringInfo(descs, ngettext("%d object in %s",
1230 											 "%d objects in %s",
1231 											 count),
1232 							 count, objdesc);
1233 			break;
1234 
1235 		default:
1236 			elog(ERROR, "unrecognized object type: %d", type);
1237 	}
1238 
1239 	pfree(objdesc);
1240 }
1241 
1242 
1243 /*
1244  * isSharedObjectPinned
1245  *		Return whether a given shared object has a SHARED_DEPENDENCY_PIN entry.
1246  *
1247  * sdepRel must be the pg_shdepend relation, already opened and suitably
1248  * locked.
1249  */
1250 static bool
isSharedObjectPinned(Oid classId,Oid objectId,Relation sdepRel)1251 isSharedObjectPinned(Oid classId, Oid objectId, Relation sdepRel)
1252 {
1253 	bool		result = false;
1254 	ScanKeyData key[2];
1255 	SysScanDesc scan;
1256 	HeapTuple	tup;
1257 
1258 	ScanKeyInit(&key[0],
1259 				Anum_pg_shdepend_refclassid,
1260 				BTEqualStrategyNumber, F_OIDEQ,
1261 				ObjectIdGetDatum(classId));
1262 	ScanKeyInit(&key[1],
1263 				Anum_pg_shdepend_refobjid,
1264 				BTEqualStrategyNumber, F_OIDEQ,
1265 				ObjectIdGetDatum(objectId));
1266 
1267 	scan = systable_beginscan(sdepRel, SharedDependReferenceIndexId, true,
1268 							  NULL, 2, key);
1269 
1270 	/*
1271 	 * Since we won't generate additional pg_shdepend entries for pinned
1272 	 * objects, there can be at most one entry referencing a pinned object.
1273 	 * Hence, it's sufficient to look at the first returned tuple; we don't
1274 	 * need to loop.
1275 	 */
1276 	tup = systable_getnext(scan);
1277 	if (HeapTupleIsValid(tup))
1278 	{
1279 		Form_pg_shdepend shdepForm = (Form_pg_shdepend) GETSTRUCT(tup);
1280 
1281 		if (shdepForm->deptype == SHARED_DEPENDENCY_PIN)
1282 			result = true;
1283 	}
1284 
1285 	systable_endscan(scan);
1286 
1287 	return result;
1288 }
1289 
1290 /*
1291  * shdepDropOwned
1292  *
1293  * Drop the objects owned by any one of the given RoleIds.  If a role has
1294  * access to an object, the grant will be removed as well (but the object
1295  * will not, of course).
1296  *
1297  * We can revoke grants immediately while doing the scan, but drops are
1298  * saved up and done all at once with performMultipleDeletions.  This
1299  * is necessary so that we don't get failures from trying to delete
1300  * interdependent objects in the wrong order.
1301  */
1302 void
shdepDropOwned(List * roleids,DropBehavior behavior)1303 shdepDropOwned(List *roleids, DropBehavior behavior)
1304 {
1305 	Relation	sdepRel;
1306 	ListCell   *cell;
1307 	ObjectAddresses *deleteobjs;
1308 
1309 	deleteobjs = new_object_addresses();
1310 
1311 	/*
1312 	 * We don't need this strong a lock here, but we'll call routines that
1313 	 * acquire RowExclusiveLock.  Better get that right now to avoid potential
1314 	 * deadlock failures.
1315 	 */
1316 	sdepRel = table_open(SharedDependRelationId, RowExclusiveLock);
1317 
1318 	/*
1319 	 * For each role, find the dependent objects and drop them using the
1320 	 * regular (non-shared) dependency management.
1321 	 */
1322 	foreach(cell, roleids)
1323 	{
1324 		Oid			roleid = lfirst_oid(cell);
1325 		ScanKeyData key[2];
1326 		SysScanDesc scan;
1327 		HeapTuple	tuple;
1328 
1329 		/* Doesn't work for pinned objects */
1330 		if (isSharedObjectPinned(AuthIdRelationId, roleid, sdepRel))
1331 		{
1332 			ObjectAddress obj;
1333 
1334 			obj.classId = AuthIdRelationId;
1335 			obj.objectId = roleid;
1336 			obj.objectSubId = 0;
1337 
1338 			ereport(ERROR,
1339 					(errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
1340 					 errmsg("cannot drop objects owned by %s because they are "
1341 							"required by the database system",
1342 							getObjectDescription(&obj))));
1343 		}
1344 
1345 		ScanKeyInit(&key[0],
1346 					Anum_pg_shdepend_refclassid,
1347 					BTEqualStrategyNumber, F_OIDEQ,
1348 					ObjectIdGetDatum(AuthIdRelationId));
1349 		ScanKeyInit(&key[1],
1350 					Anum_pg_shdepend_refobjid,
1351 					BTEqualStrategyNumber, F_OIDEQ,
1352 					ObjectIdGetDatum(roleid));
1353 
1354 		scan = systable_beginscan(sdepRel, SharedDependReferenceIndexId, true,
1355 								  NULL, 2, key);
1356 
1357 		while ((tuple = systable_getnext(scan)) != NULL)
1358 		{
1359 			Form_pg_shdepend sdepForm = (Form_pg_shdepend) GETSTRUCT(tuple);
1360 			ObjectAddress obj;
1361 
1362 			/*
1363 			 * We only operate on shared objects and objects in the current
1364 			 * database
1365 			 */
1366 			if (sdepForm->dbid != MyDatabaseId &&
1367 				sdepForm->dbid != InvalidOid)
1368 				continue;
1369 
1370 			switch (sdepForm->deptype)
1371 			{
1372 					/* Shouldn't happen */
1373 				case SHARED_DEPENDENCY_PIN:
1374 				case SHARED_DEPENDENCY_INVALID:
1375 					elog(ERROR, "unexpected dependency type");
1376 					break;
1377 				case SHARED_DEPENDENCY_ACL:
1378 					RemoveRoleFromObjectACL(roleid,
1379 											sdepForm->classid,
1380 											sdepForm->objid);
1381 					break;
1382 				case SHARED_DEPENDENCY_POLICY:
1383 
1384 					/*
1385 					 * Try to remove role from policy; if unable to, remove
1386 					 * policy.
1387 					 */
1388 					if (!RemoveRoleFromObjectPolicy(roleid,
1389 													sdepForm->classid,
1390 													sdepForm->objid))
1391 					{
1392 						obj.classId = sdepForm->classid;
1393 						obj.objectId = sdepForm->objid;
1394 						obj.objectSubId = sdepForm->objsubid;
1395 
1396 						/*
1397 						 * Acquire lock on object, then verify this dependency
1398 						 * is still relevant.  If not, the object might have
1399 						 * been dropped or the policy modified.  Ignore the
1400 						 * object in that case.
1401 						 */
1402 						AcquireDeletionLock(&obj, 0);
1403 						if (!systable_recheck_tuple(scan, tuple))
1404 						{
1405 							ReleaseDeletionLock(&obj);
1406 							break;
1407 						}
1408 						add_exact_object_address(&obj, deleteobjs);
1409 					}
1410 					break;
1411 				case SHARED_DEPENDENCY_OWNER:
1412 					/* If a local object, save it for deletion below */
1413 					if (sdepForm->dbid == MyDatabaseId)
1414 					{
1415 						obj.classId = sdepForm->classid;
1416 						obj.objectId = sdepForm->objid;
1417 						obj.objectSubId = sdepForm->objsubid;
1418 						/* as above */
1419 						AcquireDeletionLock(&obj, 0);
1420 						if (!systable_recheck_tuple(scan, tuple))
1421 						{
1422 							ReleaseDeletionLock(&obj);
1423 							break;
1424 						}
1425 						add_exact_object_address(&obj, deleteobjs);
1426 					}
1427 					break;
1428 			}
1429 		}
1430 
1431 		systable_endscan(scan);
1432 	}
1433 
1434 	/*
1435 	 * For stability of deletion-report ordering, sort the objects into
1436 	 * approximate reverse creation order before deletion.  (This might also
1437 	 * make the deletion go a bit faster, since there's less chance of having
1438 	 * to rearrange the objects due to dependencies.)
1439 	 */
1440 	sort_object_addresses(deleteobjs);
1441 
1442 	/* the dependency mechanism does the actual work */
1443 	performMultipleDeletions(deleteobjs, behavior, 0);
1444 
1445 	table_close(sdepRel, RowExclusiveLock);
1446 
1447 	free_object_addresses(deleteobjs);
1448 }
1449 
1450 /*
1451  * shdepReassignOwned
1452  *
1453  * Change the owner of objects owned by any of the roles in roleids to
1454  * newrole.  Grants are not touched.
1455  */
1456 void
shdepReassignOwned(List * roleids,Oid newrole)1457 shdepReassignOwned(List *roleids, Oid newrole)
1458 {
1459 	Relation	sdepRel;
1460 	ListCell   *cell;
1461 
1462 	/*
1463 	 * We don't need this strong a lock here, but we'll call routines that
1464 	 * acquire RowExclusiveLock.  Better get that right now to avoid potential
1465 	 * deadlock problems.
1466 	 */
1467 	sdepRel = table_open(SharedDependRelationId, RowExclusiveLock);
1468 
1469 	foreach(cell, roleids)
1470 	{
1471 		SysScanDesc scan;
1472 		ScanKeyData key[2];
1473 		HeapTuple	tuple;
1474 		Oid			roleid = lfirst_oid(cell);
1475 
1476 		/* Refuse to work on pinned roles */
1477 		if (isSharedObjectPinned(AuthIdRelationId, roleid, sdepRel))
1478 		{
1479 			ObjectAddress obj;
1480 
1481 			obj.classId = AuthIdRelationId;
1482 			obj.objectId = roleid;
1483 			obj.objectSubId = 0;
1484 
1485 			ereport(ERROR,
1486 					(errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
1487 					 errmsg("cannot reassign ownership of objects owned by %s because they are required by the database system",
1488 							getObjectDescription(&obj))));
1489 
1490 			/*
1491 			 * There's no need to tell the whole truth, which is that we
1492 			 * didn't track these dependencies at all ...
1493 			 */
1494 		}
1495 
1496 		ScanKeyInit(&key[0],
1497 					Anum_pg_shdepend_refclassid,
1498 					BTEqualStrategyNumber, F_OIDEQ,
1499 					ObjectIdGetDatum(AuthIdRelationId));
1500 		ScanKeyInit(&key[1],
1501 					Anum_pg_shdepend_refobjid,
1502 					BTEqualStrategyNumber, F_OIDEQ,
1503 					ObjectIdGetDatum(roleid));
1504 
1505 		scan = systable_beginscan(sdepRel, SharedDependReferenceIndexId, true,
1506 								  NULL, 2, key);
1507 
1508 		while ((tuple = systable_getnext(scan)) != NULL)
1509 		{
1510 			Form_pg_shdepend sdepForm = (Form_pg_shdepend) GETSTRUCT(tuple);
1511 
1512 			/*
1513 			 * We only operate on shared objects and objects in the current
1514 			 * database
1515 			 */
1516 			if (sdepForm->dbid != MyDatabaseId &&
1517 				sdepForm->dbid != InvalidOid)
1518 				continue;
1519 
1520 			/* Unexpected because we checked for pins above */
1521 			if (sdepForm->deptype == SHARED_DEPENDENCY_PIN)
1522 				elog(ERROR, "unexpected shared pin");
1523 
1524 			/* We leave non-owner dependencies alone */
1525 			if (sdepForm->deptype != SHARED_DEPENDENCY_OWNER)
1526 				continue;
1527 
1528 			/* Issue the appropriate ALTER OWNER call */
1529 			switch (sdepForm->classid)
1530 			{
1531 				case TypeRelationId:
1532 					AlterTypeOwner_oid(sdepForm->objid, newrole, true);
1533 					break;
1534 
1535 				case NamespaceRelationId:
1536 					AlterSchemaOwner_oid(sdepForm->objid, newrole);
1537 					break;
1538 
1539 				case RelationRelationId:
1540 
1541 					/*
1542 					 * Pass recursing = true so that we don't fail on indexes,
1543 					 * owned sequences, etc when we happen to visit them
1544 					 * before their parent table.
1545 					 */
1546 					ATExecChangeOwner(sdepForm->objid, newrole, true, AccessExclusiveLock);
1547 					break;
1548 
1549 				case DefaultAclRelationId:
1550 
1551 					/*
1552 					 * Ignore default ACLs; they should be handled by DROP
1553 					 * OWNED, not REASSIGN OWNED.
1554 					 */
1555 					break;
1556 
1557 				case UserMappingRelationId:
1558 					/* ditto */
1559 					break;
1560 
1561 				case ForeignServerRelationId:
1562 					AlterForeignServerOwner_oid(sdepForm->objid, newrole);
1563 					break;
1564 
1565 				case ForeignDataWrapperRelationId:
1566 					AlterForeignDataWrapperOwner_oid(sdepForm->objid, newrole);
1567 					break;
1568 
1569 				case EventTriggerRelationId:
1570 					AlterEventTriggerOwner_oid(sdepForm->objid, newrole);
1571 					break;
1572 
1573 				case PublicationRelationId:
1574 					AlterPublicationOwner_oid(sdepForm->objid, newrole);
1575 					break;
1576 
1577 				case SubscriptionRelationId:
1578 					AlterSubscriptionOwner_oid(sdepForm->objid, newrole);
1579 					break;
1580 
1581 					/* Generic alter owner cases */
1582 				case CollationRelationId:
1583 				case ConversionRelationId:
1584 				case OperatorRelationId:
1585 				case ProcedureRelationId:
1586 				case LanguageRelationId:
1587 				case LargeObjectRelationId:
1588 				case OperatorFamilyRelationId:
1589 				case OperatorClassRelationId:
1590 				case ExtensionRelationId:
1591 				case StatisticExtRelationId:
1592 				case TableSpaceRelationId:
1593 				case DatabaseRelationId:
1594 				case TSConfigRelationId:
1595 				case TSDictionaryRelationId:
1596 					{
1597 						Oid			classId = sdepForm->classid;
1598 						Relation	catalog;
1599 
1600 						if (classId == LargeObjectRelationId)
1601 							classId = LargeObjectMetadataRelationId;
1602 
1603 						catalog = table_open(classId, RowExclusiveLock);
1604 
1605 						AlterObjectOwner_internal(catalog, sdepForm->objid,
1606 												  newrole);
1607 
1608 						table_close(catalog, NoLock);
1609 					}
1610 					break;
1611 
1612 				default:
1613 					elog(ERROR, "unexpected classid %u", sdepForm->classid);
1614 					break;
1615 			}
1616 			/* Make sure the next iteration will see my changes */
1617 			CommandCounterIncrement();
1618 		}
1619 
1620 		systable_endscan(scan);
1621 	}
1622 
1623 	table_close(sdepRel, RowExclusiveLock);
1624 }
1625