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superuser.c
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1/*-------------------------------------------------------------------------
2 *
3 * superuser.c
4 * The superuser() function. Determines if user has superuser privilege.
5 *
6 * All code should use either of these two functions to find out
7 * whether a given user is a superuser, rather than examining
8 * pg_authid.rolsuper directly, so that the escape hatch built in for
9 * the single-user case works.
10 *
11 *
12 * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
13 * Portions Copyright (c) 1994, Regents of the University of California
14 *
15 *
16 * IDENTIFICATION
17 * src/backend/utils/misc/superuser.c
18 *
19 *-------------------------------------------------------------------------
20 */
21#include "postgres.h"
22
23#include "access/htup_details.h"
24#include "catalog/pg_authid.h"
25#include "miscadmin.h"
26#include "utils/inval.h"
27#include "utils/syscache.h"
28
29/*
30 * In common cases the same roleid (ie, the session or current ID) will
31 * be queried repeatedly. So we maintain a simple one-entry cache for
32 * the status of the last requested roleid. The cache can be flushed
33 * at need by watching for cache update events on pg_authid.
34 */
35static Oid last_roleid = InvalidOid; /* InvalidOid == cache not valid */
36static bool last_roleid_is_super = false;
37static bool roleid_callback_registered = false;
38
39static void RoleidCallback(Datum arg, int cacheid, uint32 hashvalue);
40
41
42/*
43 * The Postgres user running this command has Postgres superuser privileges
44 */
45bool
47{
48 return superuser_arg(GetUserId());
49}
50
51
52/*
53 * The specified role has Postgres superuser privileges
54 */
55bool
57{
58 bool result;
59 HeapTuple rtup;
60
61 /* Quick out for cache hit */
62 if (OidIsValid(last_roleid) && last_roleid == roleid)
64
65 /* Special escape path in case you deleted all your users. */
66 if (!IsUnderPostmaster && roleid == BOOTSTRAP_SUPERUSERID)
67 return true;
68
69 /* OK, look up the information in pg_authid */
70 rtup = SearchSysCache1(AUTHOID, ObjectIdGetDatum(roleid));
71 if (HeapTupleIsValid(rtup))
72 {
73 result = ((Form_pg_authid) GETSTRUCT(rtup))->rolsuper;
74 ReleaseSysCache(rtup);
75 }
76 else
77 {
78 /* Report "not superuser" for invalid roleids */
79 result = false;
80 }
81
82 /* If first time through, set up callback for cache flushes */
84 {
87 (Datum) 0);
89 }
90
91 /* Cache the result for next time */
92 last_roleid = roleid;
93 last_roleid_is_super = result;
94
95 return result;
96}
97
98/*
99 * RoleidCallback
100 * Syscache inval callback function
101 */
102static void
103RoleidCallback(Datum arg, int cacheid, uint32 hashvalue)
104{
105 /* Invalidate our local cache in case role's superuserness changed */
107}
uint32_t uint32
Definition: c.h:485
#define OidIsValid(objectId)
Definition: c.h:729
bool IsUnderPostmaster
Definition: globals.c:119
#define HeapTupleIsValid(tuple)
Definition: htup.h:78
#define GETSTRUCT(TUP)
Definition: htup_details.h:653
void CacheRegisterSyscacheCallback(int cacheid, SyscacheCallbackFunction func, Datum arg)
Definition: inval.c:1704
Oid GetUserId(void)
Definition: miscinit.c:517
bool rolsuper
Definition: pg_authid.h:35
FormData_pg_authid * Form_pg_authid
Definition: pg_authid.h:56
void * arg
uintptr_t Datum
Definition: postgres.h:64
static Datum ObjectIdGetDatum(Oid X)
Definition: postgres.h:252
#define InvalidOid
Definition: postgres_ext.h:36
unsigned int Oid
Definition: postgres_ext.h:31
static Oid last_roleid
Definition: superuser.c:35
static bool roleid_callback_registered
Definition: superuser.c:37
static void RoleidCallback(Datum arg, int cacheid, uint32 hashvalue)
Definition: superuser.c:103
bool superuser_arg(Oid roleid)
Definition: superuser.c:56
static bool last_roleid_is_super
Definition: superuser.c:36
bool superuser(void)
Definition: superuser.c:46
void ReleaseSysCache(HeapTuple tuple)
Definition: syscache.c:269
HeapTuple SearchSysCache1(int cacheId, Datum key1)
Definition: syscache.c:221