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postinit.c
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postinit.c
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/*-------------------------------------------------------------------------
*
* postinit.c
* postgres initialization utilities
*
* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/utils/init/postinit.c
*
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <ctype.h>
#include <fcntl.h>
#include <unistd.h>
#include "access/genam.h"
#include "access/heapam.h"
#include "access/htup_details.h"
#include "access/session.h"
#include "access/sysattr.h"
#include "access/tableam.h"
#include "access/xact.h"
#include "access/xlog.h"
#include "access/xloginsert.h"
#include "catalog/catalog.h"
#include "catalog/namespace.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_database.h"
#include "catalog/pg_db_role_setting.h"
#include "catalog/pg_tablespace.h"
#include "libpq/auth.h"
#include "libpq/libpq-be.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "postmaster/postmaster.h"
#include "replication/slot.h"
#include "replication/walsender.h"
#include "storage/bufmgr.h"
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/lmgr.h"
#include "storage/proc.h"
#include "storage/procarray.h"
#include "storage/procsignal.h"
#include "storage/sinvaladt.h"
#include "storage/smgr.h"
#include "storage/sync.h"
#include "tcop/tcopprot.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/memutils.h"
#include "utils/pg_locale.h"
#include "utils/portal.h"
#include "utils/ps_status.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/timeout.h"
static HeapTuple GetDatabaseTuple(const char *dbname);
static HeapTuple GetDatabaseTupleByOid(Oid dboid);
static void PerformAuthentication(Port *port);
static void CheckMyDatabase(const char *name, bool am_superuser, bool override_allow_connections);
static void ShutdownPostgres(int code, Datum arg);
static void StatementTimeoutHandler(void);
static void LockTimeoutHandler(void);
static void IdleInTransactionSessionTimeoutHandler(void);
static void IdleSessionTimeoutHandler(void);
static void IdleStatsUpdateTimeoutHandler(void);
static void ClientCheckTimeoutHandler(void);
static bool ThereIsAtLeastOneRole(void);
static void process_startup_options(Port *port, bool am_superuser);
static void process_settings(Oid databaseid, Oid roleid);
/*** InitPostgres support ***/
/*
* GetDatabaseTuple -- fetch the pg_database row for a database
*
* This is used during backend startup when we don't yet have any access to
* system catalogs in general. In the worst case, we can seqscan pg_database
* using nothing but the hard-wired descriptor that relcache.c creates for
* pg_database. In more typical cases, relcache.c was able to load
* descriptors for both pg_database and its indexes from the shared relcache
* cache file, and so we can do an indexscan. criticalSharedRelcachesBuilt
* tells whether we got the cached descriptors.
*/
static HeapTuple
GetDatabaseTuple(const char *dbname)
{
HeapTuple tuple;
Relation relation;
SysScanDesc scan;
ScanKeyData key[1];
/*
* form a scan key
*/
ScanKeyInit(&key[0],
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(dbname));
/*
* Open pg_database and fetch a tuple. Force heap scan if we haven't yet
* built the critical shared relcache entries (i.e., we're starting up
* without a shared relcache cache file).
*/
relation = table_open(DatabaseRelationId, AccessShareLock);
scan = systable_beginscan(relation, DatabaseNameIndexId,
criticalSharedRelcachesBuilt,
NULL,
1, key);
tuple = systable_getnext(scan);
/* Must copy tuple before releasing buffer */
if (HeapTupleIsValid(tuple))
tuple = heap_copytuple(tuple);
/* all done */
systable_endscan(scan);
table_close(relation, AccessShareLock);
return tuple;
}
/*
* GetDatabaseTupleByOid -- as above, but search by database OID
*/
static HeapTuple
GetDatabaseTupleByOid(Oid dboid)
{
HeapTuple tuple;
Relation relation;
SysScanDesc scan;
ScanKeyData key[1];
/*
* form a scan key
*/
ScanKeyInit(&key[0],
Anum_pg_database_oid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(dboid));
/*
* Open pg_database and fetch a tuple. Force heap scan if we haven't yet
* built the critical shared relcache entries (i.e., we're starting up
* without a shared relcache cache file).
*/
relation = table_open(DatabaseRelationId, AccessShareLock);
scan = systable_beginscan(relation, DatabaseOidIndexId,
criticalSharedRelcachesBuilt,
NULL,
1, key);
tuple = systable_getnext(scan);
/* Must copy tuple before releasing buffer */
if (HeapTupleIsValid(tuple))
tuple = heap_copytuple(tuple);
/* all done */
systable_endscan(scan);
table_close(relation, AccessShareLock);
return tuple;
}
/*
* PerformAuthentication -- authenticate a remote client
*
* returns: nothing. Will not return at all if there's any failure.
*/
static void
PerformAuthentication(Port *port)
{
/* This should be set already, but let's make sure */
ClientAuthInProgress = true; /* limit visibility of log messages */
/*
* In EXEC_BACKEND case, we didn't inherit the contents of pg_hba.conf
* etcetera from the postmaster, and have to load them ourselves.
*
* FIXME: [fork/exec] Ugh. Is there a way around this overhead?
*/
#ifdef EXEC_BACKEND
/*
* load_hba() and load_ident() want to work within the PostmasterContext,
* so create that if it doesn't exist (which it won't). We'll delete it
* again later, in PostgresMain.
*/
if (PostmasterContext == NULL)
PostmasterContext = AllocSetContextCreate(TopMemoryContext,
"Postmaster",
ALLOCSET_DEFAULT_SIZES);
if (!load_hba())
{
/*
* It makes no sense to continue if we fail to load the HBA file,
* since there is no way to connect to the database in this case.
*/
ereport(FATAL,
(errmsg("could not load pg_hba.conf")));
}
if (!load_ident())
{
/*
* It is ok to continue if we fail to load the IDENT file, although it
* means that you cannot log in using any of the authentication
* methods that need a user name mapping. load_ident() already logged
* the details of error to the log.
*/
}
#endif
/*
* Set up a timeout in case a buggy or malicious client fails to respond
* during authentication. Since we're inside a transaction and might do
* database access, we have to use the statement_timeout infrastructure.
*/
enable_timeout_after(STATEMENT_TIMEOUT, AuthenticationTimeout * 1000);
/*
* Now perform authentication exchange.
*/
set_ps_display("authentication");
ClientAuthentication(port); /* might not return, if failure */
/*
* Done with authentication. Disable the timeout, and log if needed.
*/
disable_timeout(STATEMENT_TIMEOUT, false);
if (Log_connections)
{
StringInfoData logmsg;
initStringInfo(&logmsg);
if (am_walsender)
appendStringInfo(&logmsg, _("replication connection authorized: user=%s"),
port->user_name);
else
appendStringInfo(&logmsg, _("connection authorized: user=%s"),
port->user_name);
if (!am_walsender)
appendStringInfo(&logmsg, _(" database=%s"), port->database_name);
if (port->application_name != NULL)
appendStringInfo(&logmsg, _(" application_name=%s"),
port->application_name);
#ifdef USE_SSL
if (port->ssl_in_use)
appendStringInfo(&logmsg, _(" SSL enabled (protocol=%s, cipher=%s, bits=%d)"),
be_tls_get_version(port),
be_tls_get_cipher(port),
be_tls_get_cipher_bits(port));
#endif
#ifdef ENABLE_GSS
if (port->gss)
{
const char *princ = be_gssapi_get_princ(port);
if (princ)
appendStringInfo(&logmsg,
_(" GSS (authenticated=%s, encrypted=%s, principal=%s)"),
be_gssapi_get_auth(port) ? _("yes") : _("no"),
be_gssapi_get_enc(port) ? _("yes") : _("no"),
princ);
else
appendStringInfo(&logmsg,
_(" GSS (authenticated=%s, encrypted=%s)"),
be_gssapi_get_auth(port) ? _("yes") : _("no"),
be_gssapi_get_enc(port) ? _("yes") : _("no"));
}
#endif
ereport(LOG, errmsg_internal("%s", logmsg.data));
pfree(logmsg.data);
}
set_ps_display("startup");
ClientAuthInProgress = false; /* client_min_messages is active now */
}
/*
* CheckMyDatabase -- fetch information from the pg_database entry for our DB
*/
static void
CheckMyDatabase(const char *name, bool am_superuser, bool override_allow_connections)
{
HeapTuple tup;
Form_pg_database dbform;
Datum datum;
bool isnull;
char *collate;
char *ctype;
char *iculocale;
/* Fetch our pg_database row normally, via syscache */
tup = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(MyDatabaseId));
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup failed for database %u", MyDatabaseId);
dbform = (Form_pg_database) GETSTRUCT(tup);
/* This recheck is strictly paranoia */
if (strcmp(name, NameStr(dbform->datname)) != 0)
ereport(FATAL,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" has disappeared from pg_database",
name),
errdetail("Database OID %u now seems to belong to \"%s\".",
MyDatabaseId, NameStr(dbform->datname))));
/*
* Check permissions to connect to the database.
*
* These checks are not enforced when in standalone mode, so that there is
* a way to recover from disabling all access to all databases, for
* example "UPDATE pg_database SET datallowconn = false;".
*
* We do not enforce them for autovacuum worker processes either.
*/
if (IsUnderPostmaster && !IsAutoVacuumWorkerProcess())
{
/*
* Check that the database is currently allowing connections.
*/
if (!dbform->datallowconn && !override_allow_connections)
ereport(FATAL,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("database \"%s\" is not currently accepting connections",
name)));
/*
* Check privilege to connect to the database. (The am_superuser test
* is redundant, but since we have the flag, might as well check it
* and save a few cycles.)
*/
if (!am_superuser &&
pg_database_aclcheck(MyDatabaseId, GetUserId(),
ACL_CONNECT) != ACLCHECK_OK)
ereport(FATAL,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied for database \"%s\"", name),
errdetail("User does not have CONNECT privilege.")));
/*
* Check connection limit for this database.
*
* There is a race condition here --- we create our PGPROC before
* checking for other PGPROCs. If two backends did this at about the
* same time, they might both think they were over the limit, while
* ideally one should succeed and one fail. Getting that to work
* exactly seems more trouble than it is worth, however; instead we
* just document that the connection limit is approximate.
*/
if (dbform->datconnlimit >= 0 &&
!am_superuser &&
CountDBConnections(MyDatabaseId) > dbform->datconnlimit)
ereport(FATAL,
(errcode(ERRCODE_TOO_MANY_CONNECTIONS),
errmsg("too many connections for database \"%s\"",
name)));
}
/*
* OK, we're golden. Next to-do item is to save the encoding info out of
* the pg_database tuple.
*/
SetDatabaseEncoding(dbform->encoding);
/* Record it as a GUC internal option, too */
SetConfigOption("server_encoding", GetDatabaseEncodingName(),
PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
/* If we have no other source of client_encoding, use server encoding */
SetConfigOption("client_encoding", GetDatabaseEncodingName(),
PGC_BACKEND, PGC_S_DYNAMIC_DEFAULT);
/* assign locale variables */
datum = SysCacheGetAttr(DATABASEOID, tup, Anum_pg_database_datcollate, &isnull);
Assert(!isnull);
collate = TextDatumGetCString(datum);
datum = SysCacheGetAttr(DATABASEOID, tup, Anum_pg_database_datctype, &isnull);
Assert(!isnull);
ctype = TextDatumGetCString(datum);
if (pg_perm_setlocale(LC_COLLATE, collate) == NULL)
ereport(FATAL,
(errmsg("database locale is incompatible with operating system"),
errdetail("The database was initialized with LC_COLLATE \"%s\", "
" which is not recognized by setlocale().", collate),
errhint("Recreate the database with another locale or install the missing locale.")));
if (pg_perm_setlocale(LC_CTYPE, ctype) == NULL)
ereport(FATAL,
(errmsg("database locale is incompatible with operating system"),
errdetail("The database was initialized with LC_CTYPE \"%s\", "
" which is not recognized by setlocale().", ctype),
errhint("Recreate the database with another locale or install the missing locale.")));
if (dbform->datlocprovider == COLLPROVIDER_ICU)
{
datum = SysCacheGetAttr(DATABASEOID, tup, Anum_pg_database_daticulocale, &isnull);
Assert(!isnull);
iculocale = TextDatumGetCString(datum);
make_icu_collator(iculocale, &default_locale);
}
else
iculocale = NULL;
default_locale.provider = dbform->datlocprovider;
/*
* Default locale is currently always deterministic. Nondeterministic
* locales currently don't support pattern matching, which would break a
* lot of things if applied globally.
*/
default_locale.deterministic = true;
/*
* Check collation version. See similar code in
* pg_newlocale_from_collation(). Note that here we warn instead of error
* in any case, so that we don't prevent connecting.
*/
datum = SysCacheGetAttr(DATABASEOID, tup, Anum_pg_database_datcollversion,
&isnull);
if (!isnull)
{
char *actual_versionstr;
char *collversionstr;
collversionstr = TextDatumGetCString(datum);
actual_versionstr = get_collation_actual_version(dbform->datlocprovider, dbform->datlocprovider == COLLPROVIDER_ICU ? iculocale : collate);
if (!actual_versionstr)
ereport(WARNING,
(errmsg("database \"%s\" has no actual collation version, but a version was recorded",
name)));
else if (strcmp(actual_versionstr, collversionstr) != 0)
ereport(WARNING,
(errmsg("database \"%s\" has a collation version mismatch",
name),
errdetail("The database was created using collation version %s, "
"but the operating system provides version %s.",
collversionstr, actual_versionstr),
errhint("Rebuild all objects in this database that use the default collation and run "
"ALTER DATABASE %s REFRESH COLLATION VERSION, "
"or build PostgreSQL with the right library version.",
quote_identifier(name))));
}
/* Make the locale settings visible as GUC variables, too */
SetConfigOption("lc_collate", collate, PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
SetConfigOption("lc_ctype", ctype, PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
check_strxfrm_bug();
ReleaseSysCache(tup);
}
/*
* pg_split_opts -- split a string of options and append it to an argv array
*
* The caller is responsible for ensuring the argv array is large enough. The
* maximum possible number of arguments added by this routine is
* (strlen(optstr) + 1) / 2.
*
* Because some option values can contain spaces we allow escaping using
* backslashes, with \\ representing a literal backslash.
*/
void
pg_split_opts(char **argv, int *argcp, const char *optstr)
{
StringInfoData s;
initStringInfo(&s);
while (*optstr)
{
bool last_was_escape = false;
resetStringInfo(&s);
/* skip over leading space */
while (isspace((unsigned char) *optstr))
optstr++;
if (*optstr == '\0')
break;
/*
* Parse a single option, stopping at the first space, unless it's
* escaped.
*/
while (*optstr)
{
if (isspace((unsigned char) *optstr) && !last_was_escape)
break;
if (!last_was_escape && *optstr == '\\')
last_was_escape = true;
else
{
last_was_escape = false;
appendStringInfoChar(&s, *optstr);
}
optstr++;
}
/* now store the option in the next argv[] position */
argv[(*argcp)++] = pstrdup(s.data);
}
pfree(s.data);
}
/*
* Initialize MaxBackends value from config options.
*
* This must be called after modules have had the chance to alter GUCs in
* shared_preload_libraries and before shared memory size is determined.
*
* Note that in EXEC_BACKEND environment, the value is passed down from
* postmaster to subprocesses via BackendParameters in SubPostmasterMain; only
* postmaster itself and processes not under postmaster control should call
* this.
*/
void
InitializeMaxBackends(void)
{
Assert(MaxBackends == 0);
/* the extra unit accounts for the autovacuum launcher */
MaxBackends = MaxConnections + autovacuum_max_workers + 1 +
max_worker_processes + max_wal_senders;
/* internal error because the values were all checked previously */
if (MaxBackends > MAX_BACKENDS)
elog(ERROR, "too many backends configured");
}
/*
* Early initialization of a backend (either standalone or under postmaster).
* This happens even before InitPostgres.
*
* This is separate from InitPostgres because it is also called by auxiliary
* processes, such as the background writer process, which may not call
* InitPostgres at all.
*/
void
BaseInit(void)
{
Assert(MyProc != NULL);
/*
* Initialize our input/output/debugging file descriptors.
*/
DebugFileOpen();
/*
* Initialize file access. Done early so other subsystems can access
* files.
*/
InitFileAccess();
/*
* Initialize statistics reporting. This needs to happen early to ensure
* that pgstat's shutdown callback runs after the shutdown callbacks of
* all subsystems that can produce stats (like e.g. transaction commits
* can).
*/
pgstat_initialize();
/* Do local initialization of storage and buffer managers */
InitSync();
smgrinit();
InitBufferPoolAccess();
/*
* Initialize temporary file access after pgstat, so that the temporary
* file shutdown hook can report temporary file statistics.
*/
InitTemporaryFileAccess();
/*
* Initialize local buffers for WAL record construction, in case we ever
* try to insert XLOG.
*/
InitXLogInsert();
/*
* Initialize replication slots after pgstat. The exit hook might need to
* drop ephemeral slots, which in turn triggers stats reporting.
*/
ReplicationSlotInitialize();
}
/* --------------------------------
* InitPostgres
* Initialize POSTGRES.
*
* The database can be specified by name, using the in_dbname parameter, or by
* OID, using the dboid parameter. In the latter case, the actual database
* name can be returned to the caller in out_dbname. If out_dbname isn't
* NULL, it must point to a buffer of size NAMEDATALEN.
*
* Similarly, the username can be passed by name, using the username parameter,
* or by OID using the useroid parameter.
*
* In bootstrap mode no parameters are used. The autovacuum launcher process
* doesn't use any parameters either, because it only goes far enough to be
* able to read pg_database; it doesn't connect to any particular database.
* In walsender mode only username is used.
*
* As of PostgreSQL 8.2, we expect InitProcess() was already called, so we
* already have a PGPROC struct ... but it's not completely filled in yet.
*
* Note:
* Be very careful with the order of calls in the InitPostgres function.
* --------------------------------
*/
void
InitPostgres(const char *in_dbname, Oid dboid, const char *username,
Oid useroid, char *out_dbname, bool override_allow_connections)
{
bool bootstrap = IsBootstrapProcessingMode();
bool am_superuser;
char *fullpath;
char dbname[NAMEDATALEN];
elog(DEBUG3, "InitPostgres");
/*
* Add my PGPROC struct to the ProcArray.
*
* Once I have done this, I am visible to other backends!
*/
InitProcessPhase2();
/*
* Initialize my entry in the shared-invalidation manager's array of
* per-backend data.
*
* Sets up MyBackendId, a unique backend identifier.
*/
MyBackendId = InvalidBackendId;
SharedInvalBackendInit(false);
if (MyBackendId > MaxBackends || MyBackendId <= 0)
elog(FATAL, "bad backend ID: %d", MyBackendId);
/* Now that we have a BackendId, we can participate in ProcSignal */
ProcSignalInit(MyBackendId);
/*
* Also set up timeout handlers needed for backend operation. We need
* these in every case except bootstrap.
*/
if (!bootstrap)
{
RegisterTimeout(DEADLOCK_TIMEOUT, CheckDeadLockAlert);
RegisterTimeout(STATEMENT_TIMEOUT, StatementTimeoutHandler);
RegisterTimeout(LOCK_TIMEOUT, LockTimeoutHandler);
RegisterTimeout(IDLE_IN_TRANSACTION_SESSION_TIMEOUT,
IdleInTransactionSessionTimeoutHandler);
RegisterTimeout(IDLE_SESSION_TIMEOUT, IdleSessionTimeoutHandler);
RegisterTimeout(CLIENT_CONNECTION_CHECK_TIMEOUT, ClientCheckTimeoutHandler);
RegisterTimeout(IDLE_STATS_UPDATE_TIMEOUT,
IdleStatsUpdateTimeoutHandler);
}
/*
* If this is either a bootstrap process or a standalone backend, start up
* the XLOG machinery, and register to have it closed down at exit. In
* other cases, the startup process is responsible for starting up the
* XLOG machinery, and the checkpointer for closing it down.
*/
if (!IsUnderPostmaster)
{
/*
* We don't yet have an aux-process resource owner, but StartupXLOG
* and ShutdownXLOG will need one. Hence, create said resource owner
* (and register a callback to clean it up after ShutdownXLOG runs).
*/
CreateAuxProcessResourceOwner();
StartupXLOG();
/* Release (and warn about) any buffer pins leaked in StartupXLOG */
ReleaseAuxProcessResources(true);
/* Reset CurrentResourceOwner to nothing for the moment */
CurrentResourceOwner = NULL;
/*
* Use before_shmem_exit() so that ShutdownXLOG() can rely on DSM
* segments etc to work (which in turn is required for pgstats).
*/
before_shmem_exit(pgstat_before_server_shutdown, 0);
before_shmem_exit(ShutdownXLOG, 0);
}
/*
* Initialize the relation cache and the system catalog caches. Note that
* no catalog access happens here; we only set up the hashtable structure.
* We must do this before starting a transaction because transaction abort
* would try to touch these hashtables.
*/
RelationCacheInitialize();
InitCatalogCache();
InitPlanCache();
/* Initialize portal manager */
EnablePortalManager();
/* Initialize status reporting */
pgstat_beinit();
/*
* Load relcache entries for the shared system catalogs. This must create
* at least entries for pg_database and catalogs used for authentication.
*/
RelationCacheInitializePhase2();
/*
* Set up process-exit callback to do pre-shutdown cleanup. This is the
* one of the first before_shmem_exit callbacks we register; thus, this
* will be one the last things we do before low-level modules like the
* buffer manager begin to close down. We need to have this in place
* before we begin our first transaction --- if we fail during the
* initialization transaction, as is entirely possible, we need the
* AbortTransaction call to clean up.
*/
before_shmem_exit(ShutdownPostgres, 0);
/* The autovacuum launcher is done here */
if (IsAutoVacuumLauncherProcess())
{
/* report this backend in the PgBackendStatus array */
pgstat_bestart();
return;
}
/*
* Start a new transaction here before first access to db, and get a
* snapshot. We don't have a use for the snapshot itself, but we're
* interested in the secondary effect that it sets RecentGlobalXmin. (This
* is critical for anything that reads heap pages, because HOT may decide
* to prune them even if the process doesn't attempt to modify any
* tuples.)
*
* FIXME: This comment is inaccurate / the code buggy. A snapshot that is
* not pushed/active does not reliably prevent HOT pruning (->xmin could
* e.g. be cleared when cache invalidations are processed).
*/
if (!bootstrap)
{
/* statement_timestamp must be set for timeouts to work correctly */
SetCurrentStatementStartTimestamp();
StartTransactionCommand();
/*
* transaction_isolation will have been set to the default by the
* above. If the default is "serializable", and we are in hot
* standby, we will fail if we don't change it to something lower.
* Fortunately, "read committed" is plenty good enough.
*/
XactIsoLevel = XACT_READ_COMMITTED;
(void) GetTransactionSnapshot();
}
/*
* Perform client authentication if necessary, then figure out our
* postgres user ID, and see if we are a superuser.
*
* In standalone mode and in autovacuum worker processes, we use a fixed
* ID, otherwise we figure it out from the authenticated user name.
*/
if (bootstrap || IsAutoVacuumWorkerProcess())
{
InitializeSessionUserIdStandalone();
am_superuser = true;
}
else if (!IsUnderPostmaster)
{
InitializeSessionUserIdStandalone();
am_superuser = true;
if (!ThereIsAtLeastOneRole())
ereport(WARNING,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("no roles are defined in this database system"),
errhint("You should immediately run CREATE USER \"%s\" SUPERUSER;.",
username != NULL ? username : "postgres")));
}
else if (IsBackgroundWorker)
{
if (username == NULL && !OidIsValid(useroid))
{
InitializeSessionUserIdStandalone();
am_superuser = true;
}
else
{
InitializeSessionUserId(username, useroid);
am_superuser = superuser();
}
}
else
{
/* normal multiuser case */
Assert(MyProcPort != NULL);
PerformAuthentication(MyProcPort);
InitializeSessionUserId(username, useroid);
am_superuser = superuser();
}
/*
* Binary upgrades only allowed super-user connections
*/
if (IsBinaryUpgrade && !am_superuser)
{
ereport(FATAL,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to connect in binary upgrade mode")));
}
/*
* The last few connection slots are reserved for superusers. Replication
* connections are drawn from slots reserved with max_wal_senders and not
* limited by max_connections or superuser_reserved_connections.
*/
if (!am_superuser && !am_walsender &&
ReservedBackends > 0 &&
!HaveNFreeProcs(ReservedBackends))
ereport(FATAL,
(errcode(ERRCODE_TOO_MANY_CONNECTIONS),
errmsg("remaining connection slots are reserved for non-replication superuser connections")));
/* Check replication permissions needed for walsender processes. */
if (am_walsender)
{
Assert(!bootstrap);
if (!superuser() && !has_rolreplication(GetUserId()))
ereport(FATAL,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser or replication role to start walsender")));
}
/*
* If this is a plain walsender only supporting physical replication, we
* don't want to connect to any particular database. Just finish the
* backend startup by processing any options from the startup packet, and
* we're done.
*/
if (am_walsender && !am_db_walsender)
{
/* process any options passed in the startup packet */
if (MyProcPort != NULL)
process_startup_options(MyProcPort, am_superuser);
/* Apply PostAuthDelay as soon as we've read all options */
if (PostAuthDelay > 0)
pg_usleep(PostAuthDelay * 1000000L);
/* initialize client encoding */
InitializeClientEncoding();
/* report this backend in the PgBackendStatus array */
pgstat_bestart();
/* close the transaction we started above */
CommitTransactionCommand();
return;
}
/*
* Set up the global variables holding database id and default tablespace.
* But note we won't actually try to touch the database just yet.
*
* We take a shortcut in the bootstrap case, otherwise we have to look up
* the db's entry in pg_database.
*/
if (bootstrap)
{
MyDatabaseId = Template1DbOid;
MyDatabaseTableSpace = DEFAULTTABLESPACE_OID;
}
else if (in_dbname != NULL)
{
HeapTuple tuple;
Form_pg_database dbform;
tuple = GetDatabaseTuple(in_dbname);
if (!HeapTupleIsValid(tuple))
ereport(FATAL,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", in_dbname)));
dbform = (Form_pg_database) GETSTRUCT(tuple);
MyDatabaseId = dbform->oid;
MyDatabaseTableSpace = dbform->dattablespace;
/* take database name from the caller, just for paranoia */
strlcpy(dbname, in_dbname, sizeof(dbname));
}
else if (OidIsValid(dboid))
{
/* caller specified database by OID */
HeapTuple tuple;
Form_pg_database dbform;
tuple = GetDatabaseTupleByOid(dboid);
if (!HeapTupleIsValid(tuple))
ereport(FATAL,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database %u does not exist", dboid)));
dbform = (Form_pg_database) GETSTRUCT(tuple);
MyDatabaseId = dbform->oid;
MyDatabaseTableSpace = dbform->dattablespace;
Assert(MyDatabaseId == dboid);
strlcpy(dbname, NameStr(dbform->datname), sizeof(dbname));
/* pass the database name back to the caller */
if (out_dbname)
strcpy(out_dbname, dbname);
}
else
{
/*
* If this is a background worker not bound to any particular
* database, we're done now. Everything that follows only makes sense
* if we are bound to a specific database. We do need to close the
* transaction we started before returning.
*/
if (!bootstrap)
{
pgstat_bestart();
CommitTransactionCommand();
}
return;
}
/*
* Now, take a writer's lock on the database we are trying to connect to.
* If there is a concurrently running DROP DATABASE on that database, this
* will block us until it finishes (and has committed its update of
* pg_database).
*
* Note that the lock is not held long, only until the end of this startup
* transaction. This is OK since we will advertise our use of the
* database in the ProcArray before dropping the lock (in fact, that's the
* next thing to do). Anyone trying a DROP DATABASE after this point will
* see us in the array once they have the lock. Ordering is important for
* this because we don't want to advertise ourselves as being in this
* database until we have the lock; otherwise we create what amounts to a
* deadlock with CountOtherDBBackends().
*
* Note: use of RowExclusiveLock here is reasonable because we envision
* our session as being a concurrent writer of the database. If we had a
* way of declaring a session as being guaranteed-read-only, we could use
* AccessShareLock for such sessions and thereby not conflict against
* CREATE DATABASE.
*/
if (!bootstrap)
LockSharedObject(DatabaseRelationId, MyDatabaseId, 0,
RowExclusiveLock);
/*
* Now we can mark our PGPROC entry with the database ID.
*
* We assume this is an atomic store so no lock is needed; though actually
* things would work fine even if it weren't atomic. Anyone searching the
* ProcArray for this database's ID should hold the database lock, so they
* would not be executing concurrently with this store. A process looking
* for another database's ID could in theory see a chance match if it read
* a partially-updated databaseId value; but as long as all such searches
* wait and retry, as in CountOtherDBBackends(), they will certainly see