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e26c539e9f
The purpose of this change is to eliminate the need for every caller of SearchSysCache, SearchSysCacheCopy, SearchSysCacheExists, GetSysCacheOid, and SearchSysCacheList to know the maximum number of allowable keys for a syscache entry (currently 4). This will make it far easier to increase the maximum number of keys in a future release should we choose to do so, and it makes the code shorter, too. Design and review by Tom Lane.
108 lines
2.8 KiB
C
108 lines
2.8 KiB
C
/*-------------------------------------------------------------------------
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*
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* superuser.c
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* The superuser() function. Determines if user has superuser privilege.
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*
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* All code should use either of these two functions to find out
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* whether a given user is a superuser, rather than examining
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* pg_authid.rolsuper directly, so that the escape hatch built in for
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* the single-user case works.
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*
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*
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* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/utils/misc/superuser.c,v 1.41 2010/02/14 18:42:18 rhaas Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "catalog/pg_authid.h"
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#include "utils/inval.h"
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#include "utils/syscache.h"
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#include "miscadmin.h"
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/*
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* In common cases the same roleid (ie, the session or current ID) will
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* be queried repeatedly. So we maintain a simple one-entry cache for
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* the status of the last requested roleid. The cache can be flushed
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* at need by watching for cache update events on pg_authid.
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*/
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static Oid last_roleid = InvalidOid; /* InvalidOid == cache not valid */
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static bool last_roleid_is_super = false;
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static bool roleid_callback_registered = false;
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static void RoleidCallback(Datum arg, int cacheid, ItemPointer tuplePtr);
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/*
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* The Postgres user running this command has Postgres superuser privileges
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*/
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bool
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superuser(void)
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{
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return superuser_arg(GetUserId());
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}
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/*
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* The specified role has Postgres superuser privileges
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*/
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bool
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superuser_arg(Oid roleid)
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{
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bool result;
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HeapTuple rtup;
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/* Quick out for cache hit */
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if (OidIsValid(last_roleid) && last_roleid == roleid)
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return last_roleid_is_super;
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/* Special escape path in case you deleted all your users. */
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if (!IsUnderPostmaster && roleid == BOOTSTRAP_SUPERUSERID)
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return true;
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/* OK, look up the information in pg_authid */
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rtup = SearchSysCache1(AUTHOID, ObjectIdGetDatum(roleid));
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if (HeapTupleIsValid(rtup))
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{
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result = ((Form_pg_authid) GETSTRUCT(rtup))->rolsuper;
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ReleaseSysCache(rtup);
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}
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else
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{
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/* Report "not superuser" for invalid roleids */
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result = false;
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}
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/* If first time through, set up callback for cache flushes */
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if (!roleid_callback_registered)
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{
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CacheRegisterSyscacheCallback(AUTHOID,
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RoleidCallback,
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(Datum) 0);
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roleid_callback_registered = true;
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}
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/* Cache the result for next time */
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last_roleid = roleid;
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last_roleid_is_super = result;
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return result;
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}
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/*
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* UseridCallback
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* Syscache inval callback function
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*/
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static void
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RoleidCallback(Datum arg, int cacheid, ItemPointer tuplePtr)
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{
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/* Invalidate our local cache in case role's superuserness changed */
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last_roleid = InvalidOid;
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}
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