utility.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 1,566 行 · 第 1/3 页

/*-------------------------------------------------------------------------
 *
 * utility.c
 *	  Contains functions which control the execution of the POSTGRES utility
 *	  commands.  At one time acted as an interface between the Lisp and C
 *	  systems.
 *
 * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.208 2003/10/02 06:34:04 petere Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/heapam.h"
#include "catalog/catalog.h"
#include "catalog/namespace.h"
#include "catalog/pg_shadow.h"
#include "commands/alter.h"
#include "commands/async.h"
#include "commands/cluster.h"
#include "commands/comment.h"
#include "commands/copy.h"
#include "commands/conversioncmds.h"
#include "commands/dbcommands.h"
#include "commands/defrem.h"
#include "commands/explain.h"
#include "commands/lockcmds.h"
#include "commands/portalcmds.h"
#include "commands/prepare.h"
#include "commands/proclang.h"
#include "commands/schemacmds.h"
#include "commands/sequence.h"
#include "commands/tablecmds.h"
#include "commands/trigger.h"
#include "commands/typecmds.h"
#include "commands/user.h"
#include "commands/vacuum.h"
#include "commands/view.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "parser/parse_clause.h"
#include "parser/parse_expr.h"
#include "parser/parse_type.h"
#include "rewrite/rewriteDefine.h"
#include "rewrite/rewriteRemove.h"
#include "tcop/pquery.h"
#include "tcop/utility.h"
#include "utils/acl.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "access/xlog.h"

/*
 * Error-checking support for DROP commands
 */

struct msgstrings
{
	char		kind;
	int			nonexistent_code;
	const char *nonexistent_msg;
	const char *nota_msg;
	const char *drophint_msg;
};

static const struct msgstrings msgstringarray[] = {
	{RELKIND_RELATION,
		ERRCODE_UNDEFINED_TABLE,
		gettext_noop("table \"%s\" does not exist"),
		gettext_noop("\"%s\" is not a table"),
	gettext_noop("Use DROP TABLE to remove a table.")},
	{RELKIND_SEQUENCE,
		ERRCODE_UNDEFINED_TABLE,
		gettext_noop("sequence \"%s\" does not exist"),
		gettext_noop("\"%s\" is not a sequence"),
	gettext_noop("Use DROP SEQUENCE to remove a sequence.")},
	{RELKIND_VIEW,
		ERRCODE_UNDEFINED_TABLE,
		gettext_noop("view \"%s\" does not exist"),
		gettext_noop("\"%s\" is not a view"),
	gettext_noop("Use DROP VIEW to remove a view.")},
	{RELKIND_INDEX,
		ERRCODE_UNDEFINED_OBJECT,
		gettext_noop("index \"%s\" does not exist"),
		gettext_noop("\"%s\" is not an index"),
	gettext_noop("Use DROP INDEX to remove an index.")},
	{RELKIND_COMPOSITE_TYPE,
		ERRCODE_UNDEFINED_OBJECT,
		gettext_noop("type \"%s\" does not exist"),
		gettext_noop("\"%s\" is not a type"),
	gettext_noop("Use DROP TYPE to remove a type.")},
	{'\0', 0, NULL, NULL, NULL}
};


static void
DropErrorMsg(char *relname, char wrongkind, char rightkind)
{
	const struct msgstrings *rentry;
	const struct msgstrings *wentry;

	for (rentry = msgstringarray; rentry->kind != '\0'; rentry++)
		if (rentry->kind == rightkind)
			break;
	Assert(rentry->kind != '\0');

	for (wentry = msgstringarray; wentry->kind != '\0'; wentry++)
		if (wentry->kind == wrongkind)
			break;
	/* wrongkind could be something we don't have in our table... */

	ereport(ERROR,
			(errcode(ERRCODE_WRONG_OBJECT_TYPE),
			 errmsg(rentry->nota_msg, relname),
			 (wentry->kind != '\0') ? errhint(wentry->drophint_msg) : 0));
}

static void
CheckDropPermissions(RangeVar *rel, char rightkind)
{
	const struct msgstrings *rentry;
	Oid			relOid;
	HeapTuple	tuple;
	Form_pg_class classform;

	for (rentry = msgstringarray; rentry->kind != '\0'; rentry++)
		if (rentry->kind == rightkind)
			break;
	Assert(rentry->kind != '\0');

	relOid = RangeVarGetRelid(rel, true);
	if (!OidIsValid(relOid))
		ereport(ERROR,
				(errcode(rentry->nonexistent_code),
				 errmsg(rentry->nonexistent_msg, rel->relname)));
	tuple = SearchSysCache(RELOID,
						   ObjectIdGetDatum(relOid),
						   0, 0, 0);
	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "cache lookup failed for relation %u", relOid);

	classform = (Form_pg_class) GETSTRUCT(tuple);

	if (classform->relkind != rightkind)
		DropErrorMsg(rel->relname, classform->relkind, rightkind);

	/* Allow DROP to either table owner or schema owner */
	if (!pg_class_ownercheck(relOid, GetUserId()) &&
		!pg_namespace_ownercheck(classform->relnamespace, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
					   rel->relname);

	if (!allowSystemTableMods && IsSystemClass(classform))
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 errmsg("permission denied: \"%s\" is a system catalog",
						rel->relname)));

	ReleaseSysCache(tuple);
}

/*
 * Verify user has ownership of specified relation, else ereport.
 *
 * If noCatalogs is true then we also deny access to system catalogs,
 * except when allowSystemTableMods is true.
 */
void
CheckRelationOwnership(RangeVar *rel, bool noCatalogs)
{
	Oid			relOid;
	HeapTuple	tuple;

	relOid = RangeVarGetRelid(rel, false);
	tuple = SearchSysCache(RELOID,
						   ObjectIdGetDatum(relOid),
						   0, 0, 0);
	if (!HeapTupleIsValid(tuple))		/* should not happen */
		elog(ERROR, "cache lookup failed for relation %u", relOid);

	if (!pg_class_ownercheck(relOid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
					   rel->relname);

	if (noCatalogs)
	{
		if (!allowSystemTableMods &&
			IsSystemClass((Form_pg_class) GETSTRUCT(tuple)))
			ereport(ERROR,
					(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				  errmsg("permission denied: \"%s\" is a system catalog",
						 rel->relname)));
	}

	ReleaseSysCache(tuple);
}


static void
check_xact_readonly(Node *parsetree)
{
	if (!XactReadOnly)
		return;

	/*
	 * Note: Commands that need to do more complicated checking are
	 * handled elsewhere.
	 */

	switch (nodeTag(parsetree))
	{
		case T_AlterDatabaseSetStmt:
		case T_AlterDomainStmt:
		case T_AlterGroupStmt:
		case T_AlterSeqStmt:
		case T_AlterTableStmt:
		case T_RenameStmt:
		case T_AlterUserStmt:
		case T_AlterUserSetStmt:
		case T_CommentStmt:
		case T_DefineStmt:
		case T_CreateCastStmt:
		case T_CreateConversionStmt:
		case T_CreatedbStmt:
		case T_CreateDomainStmt:
		case T_CreateFunctionStmt:
		case T_CreateGroupStmt:
		case T_IndexStmt:
		case T_CreatePLangStmt:
		case T_CreateOpClassStmt:
		case T_RuleStmt:
		case T_CreateSchemaStmt:
		case T_CreateSeqStmt:
		case T_CreateStmt:
		case T_CreateTrigStmt:
		case T_CompositeTypeStmt:
		case T_CreateUserStmt:
		case T_ViewStmt:
		case T_RemoveAggrStmt:
		case T_DropCastStmt:
		case T_DropStmt:
		case T_DropdbStmt:
		case T_RemoveFuncStmt:
		case T_DropGroupStmt:
		case T_DropPLangStmt:
		case T_RemoveOperStmt:
		case T_RemoveOpClassStmt:
		case T_DropPropertyStmt:
		case T_DropUserStmt:
		case T_GrantStmt:
		case T_TruncateStmt:
			ereport(ERROR,
					(errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
					 errmsg("transaction is read-only")));
			break;
		default:
			/* do nothing */
			break;
	}
}


/*
 * ProcessUtility
 *		general utility function invoker
 *
 *	parsetree: the parse tree for the utility statement
 *	dest: where to send results
 *	completionTag: points to a buffer of size COMPLETION_TAG_BUFSIZE
 *		in which to store a command completion status string.
 *
 * completionTag is only set nonempty if we want to return a nondefault
 * status (currently, only used for MOVE/FETCH).
 *
 * completionTag may be NULL if caller doesn't want a status string.
 */
void
ProcessUtility(Node *parsetree,
			   DestReceiver *dest,
			   char *completionTag)
{
	check_xact_readonly(parsetree);

	if (completionTag)
		completionTag[0] = '\0';

	switch (nodeTag(parsetree))
	{
			/*
			 * ******************** transactions ********************
			 */
		case T_TransactionStmt:
			{
				TransactionStmt *stmt = (TransactionStmt *) parsetree;

				switch (stmt->kind)
				{
					case TRANS_STMT_BEGIN:
						BeginTransactionBlock();
						break;

						/*
						 * START TRANSACTION, as defined by SQL99:
						 * Identical to BEGIN, except that it takes a few
						 * additional options.
						 */
					case TRANS_STMT_START:
						{
							BeginTransactionBlock();

							if (stmt->options)
							{
								List	   *head;

								foreach(head, stmt->options)
								{
									DefElem    *item = (DefElem *) lfirst(head);

									if (strcmp(item->defname, "transaction_isolation") == 0)
										SetPGVariable("transaction_isolation",
											makeList1(item->arg), false);
									else if (strcmp(item->defname, "transaction_read_only") == 0)
										SetPGVariable("transaction_read_only",
											makeList1(item->arg), false);
								}
							}
						}
						break;

					case TRANS_STMT_COMMIT:
						EndTransactionBlock();
						break;

					case TRANS_STMT_ROLLBACK:
						UserAbortTransactionBlock();
						break;
				}
			}
			break;

			/*
			 * Portal (cursor) manipulation
			 */
		case T_DeclareCursorStmt:
			PerformCursorOpen((DeclareCursorStmt *) parsetree);
			break;

		case T_ClosePortalStmt:
			{
				ClosePortalStmt *stmt = (ClosePortalStmt *) parsetree;

				PerformPortalClose(stmt->portalname);
			}
			break;

		case T_FetchStmt:
			PerformPortalFetch((FetchStmt *) parsetree, dest,
							   completionTag);
			break;

			/*
			 * relation and attribute manipulation
			 */
		case T_CreateSchemaStmt:
			CreateSchemaCommand((CreateSchemaStmt *) parsetree);
			break;

		case T_CreateStmt:
			{
				Oid			relOid;

				relOid = DefineRelation((CreateStmt *) parsetree,
										RELKIND_RELATION);

				/*
				 * Let AlterTableCreateToastTable decide if this one needs
				 * a secondary relation too.
				 */
				CommandCounterIncrement();
				AlterTableCreateToastTable(relOid, true);
			}
			break;

		case T_DropStmt:
			{
				DropStmt   *stmt = (DropStmt *) parsetree;
				List	   *arg;

				foreach(arg, stmt->objects)
				{
					List	   *names = (List *) lfirst(arg);
					RangeVar   *rel;

					switch (stmt->removeType)
					{
						case OBJECT_TABLE:
							rel = makeRangeVarFromNameList(names);
							CheckDropPermissions(rel, RELKIND_RELATION);
							RemoveRelation(rel, stmt->behavior);
							break;

						case OBJECT_SEQUENCE:
							rel = makeRangeVarFromNameList(names);
							CheckDropPermissions(rel, RELKIND_SEQUENCE);
							RemoveRelation(rel, stmt->behavior);
							break;

						case OBJECT_VIEW:
							rel = makeRangeVarFromNameList(names);
							CheckDropPermissions(rel, RELKIND_VIEW);
							RemoveView(rel, stmt->behavior);
							break;

						case OBJECT_INDEX:
							rel = makeRangeVarFromNameList(names);
							CheckDropPermissions(rel, RELKIND_INDEX);
							RemoveIndex(rel, stmt->behavior);
							break;

						case OBJECT_TYPE:
							/* RemoveType does its own permissions checks */
							RemoveType(names, stmt->behavior);
							break;

						case OBJECT_DOMAIN:

							/*
							 * RemoveDomain does its own permissions
							 * checks
							 */
							RemoveDomain(names, stmt->behavior);
							break;

						case OBJECT_CONVERSION:
							DropConversionCommand(names, stmt->behavior);
							break;

						case OBJECT_SCHEMA:

							/*
							 * RemoveSchema does its own permissions
							 * checks
							 */
							RemoveSchema(names, stmt->behavior);
							break;

						default:
							elog(ERROR, "unrecognized drop object type: %d",
								 (int) stmt->removeType);
							break;
					}

					/*
					 * We used to need to do CommandCounterIncrement()
					 * here, but now it's done inside performDeletion().
					 */
				}
			}
			break;

		case T_TruncateStmt:
			{
				TruncateStmt *stmt = (TruncateStmt *) parsetree;

				TruncateRelation(stmt->relation);
			}
			break;

		case T_CommentStmt:
			CommentObject((CommentStmt *) parsetree);
			break;

		case T_CopyStmt:
			DoCopy((CopyStmt *) parsetree);
			break;

		case T_PrepareStmt:
			PrepareQuery((PrepareStmt *) parsetree);
			break;

		case T_ExecuteStmt:
			ExecuteQuery((ExecuteStmt *) parsetree, dest);
			break;

		case T_DeallocateStmt:
			DeallocateQuery((DeallocateStmt *) parsetree);
			break;

			/*
			 * schema
			 */
		case T_RenameStmt:
			ExecRenameStmt((RenameStmt *) parsetree);
			break;

			/* various Alter Table forms */

		case T_AlterTableStmt:
			{
				AlterTableStmt *stmt = (AlterTableStmt *) parsetree;
				Oid			relid;

				relid = RangeVarGetRelid(stmt->relation, false);

				/*
				 * Some or all of these functions are recursive to cover
				 * inherited things, so permission checks are done there.
				 */
				switch (stmt->subtype)
				{
					case 'A':	/* ADD COLUMN */

						/*
						 * Recursively add column to table and, if
						 * requested, to descendants
						 */