miscadmin.h

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/*-------------------------------------------------------------------------
 *
 * miscadmin.h
 *    This file contains general postgres administration and initialization
 *    stuff that used to be spread out between the following files:
 *      globals.h                       global variables
 *      pdir.h                          directory path crud
 *      pinit.h                         postgres initialization
 *      pmod.h                          processing modes
 *    Over time, this has also become the preferred place for widely known
 *    resource-limitation stuff, such as work_mem and check_stack_depth().
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/miscadmin.h
 *
 * NOTES
 *    some of the information in this file should be moved to other files.
 *
 *-------------------------------------------------------------------------
 */
#ifndef MISCADMIN_H
#define MISCADMIN_H
 
#include <signal.h>
 
#include "datatype/timestamp.h" /* for TimestampTz */
#include "pgtime.h"             /* for pg_time_t */
 
 
#define InvalidPid              (-1)
 
 
/*****************************************************************************
 *    System interrupt and critical section handling
 *
 * There are two types of interrupts that a running backend needs to accept
 * without messing up its state: QueryCancel (SIGINT) and ProcDie (SIGTERM).
 * In both cases, we need to be able to clean up the current transaction
 * gracefully, so we can't respond to the interrupt instantaneously ---
 * there's no guarantee that internal data structures would be self-consistent
 * if the code is interrupted at an arbitrary instant.  Instead, the signal
 * handlers set flags that are checked periodically during execution.
 *
 * The CHECK_FOR_INTERRUPTS() macro is called at strategically located spots
 * where it is normally safe to accept a cancel or die interrupt.  In some
 * cases, we invoke CHECK_FOR_INTERRUPTS() inside low-level subroutines that
 * might sometimes be called in contexts that do *not* want to allow a cancel
 * or die interrupt.  The HOLD_INTERRUPTS() and RESUME_INTERRUPTS() macros
 * allow code to ensure that no cancel or die interrupt will be accepted,
 * even if CHECK_FOR_INTERRUPTS() gets called in a subroutine.  The interrupt
 * will be held off until CHECK_FOR_INTERRUPTS() is done outside any
 * HOLD_INTERRUPTS() ... RESUME_INTERRUPTS() section.
 *
 * There is also a mechanism to prevent query cancel interrupts, while still
 * allowing die interrupts: HOLD_CANCEL_INTERRUPTS() and
 * RESUME_CANCEL_INTERRUPTS().
 *
 * Note that ProcessInterrupts() has also acquired a number of tasks that
 * do not necessarily cause a query-cancel-or-die response.  Hence, it's
 * possible that it will just clear InterruptPending and return.
 *
 * INTERRUPTS_PENDING_CONDITION() can be checked to see whether an
 * interrupt needs to be serviced, without trying to do so immediately.
 * Some callers are also interested in INTERRUPTS_CAN_BE_PROCESSED(),
 * which tells whether ProcessInterrupts is sure to clear the interrupt.
 *
 * Special mechanisms are used to let an interrupt be accepted when we are
 * waiting for a lock or when we are waiting for command input (but, of
 * course, only if the interrupt holdoff counter is zero).  See the
 * related code for details.
 *
 * A lost connection is handled similarly, although the loss of connection
 * does not raise a signal, but is detected when we fail to write to the
 * socket. If there was a signal for a broken connection, we could make use of
 * it by setting ClientConnectionLost in the signal handler.
 *
 * A related, but conceptually distinct, mechanism is the "critical section"
 * mechanism.  A critical section not only holds off cancel/die interrupts,
 * but causes any ereport(ERROR) or ereport(FATAL) to become ereport(PANIC)
 * --- that is, a system-wide reset is forced.  Needless to say, only really
 * *critical* code should be marked as a critical section!  Currently, this
 * mechanism is only used for XLOG-related code.
 *
 *****************************************************************************/
 
/* in globals.c */
/* these are marked volatile because they are set by signal handlers: */
extern PGDLLIMPORT volatile sig_atomic_t InterruptPending;
extern PGDLLIMPORT volatile sig_atomic_t QueryCancelPending;
extern PGDLLIMPORT volatile sig_atomic_t ProcDiePending;
extern PGDLLIMPORT volatile sig_atomic_t IdleInTransactionSessionTimeoutPending;
extern PGDLLIMPORT volatile sig_atomic_t TransactionTimeoutPending;
extern PGDLLIMPORT volatile sig_atomic_t IdleSessionTimeoutPending;
extern PGDLLIMPORT volatile sig_atomic_t ProcSignalBarrierPending;
extern PGDLLIMPORT volatile sig_atomic_t LogMemoryContextPending;
extern PGDLLIMPORT volatile sig_atomic_t IdleStatsUpdateTimeoutPending;
extern PGDLLIMPORT volatile sig_atomic_t PublishMemoryContextPending;
 
extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
 
/* these are marked volatile because they are examined by signal handlers: */
extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;
extern PGDLLIMPORT volatile uint32 QueryCancelHoldoffCount;
extern PGDLLIMPORT volatile uint32 CritSectionCount;
 
/* in tcop/postgres.c */
extern void ProcessInterrupts(void);
 
/* Test whether an interrupt is pending */
#ifndef WIN32
#define INTERRUPTS_PENDING_CONDITION() \
    (unlikely(InterruptPending))
#else
#define INTERRUPTS_PENDING_CONDITION() \
    (unlikely(UNBLOCKED_SIGNAL_QUEUE()) ? pgwin32_dispatch_queued_signals() : 0, \
     unlikely(InterruptPending))
#endif
 
/* Service interrupt, if one is pending and it's safe to service it now */
#define CHECK_FOR_INTERRUPTS() \
do { \
    if (INTERRUPTS_PENDING_CONDITION()) \
        ProcessInterrupts(); \
} while(0)
 
/* Is ProcessInterrupts() guaranteed to clear InterruptPending? */
#define INTERRUPTS_CAN_BE_PROCESSED() \
    (InterruptHoldoffCount == 0 && CritSectionCount == 0 && \
     QueryCancelHoldoffCount == 0)
 
#define HOLD_INTERRUPTS()  (InterruptHoldoffCount++)
 
#define RESUME_INTERRUPTS() \
do { \
    Assert(InterruptHoldoffCount > 0); \
    InterruptHoldoffCount--; \
} while(0)
 
#define HOLD_CANCEL_INTERRUPTS()  (QueryCancelHoldoffCount++)
 
#define RESUME_CANCEL_INTERRUPTS() \
do { \
    Assert(QueryCancelHoldoffCount > 0); \
    QueryCancelHoldoffCount--; \
} while(0)
 
#define START_CRIT_SECTION()  (CritSectionCount++)
 
#define END_CRIT_SECTION() \
do { \
    Assert(CritSectionCount > 0); \
    CritSectionCount--; \
} while(0)
 
 
/*****************************************************************************
 *    globals.h --                                                           *
 *****************************************************************************/
 
/*
 * from utils/init/globals.c
 */
extern PGDLLIMPORT pid_t PostmasterPid;
extern PGDLLIMPORT bool IsPostmasterEnvironment;
extern PGDLLIMPORT bool IsUnderPostmaster;
extern PGDLLIMPORT bool IsBinaryUpgrade;
 
extern PGDLLIMPORT bool ExitOnAnyError;
 
extern PGDLLIMPORT char *DataDir;
extern PGDLLIMPORT int data_directory_mode;
 
extern PGDLLIMPORT int NBuffers;
extern PGDLLIMPORT int MaxBackends;
extern PGDLLIMPORT int MaxConnections;
extern PGDLLIMPORT int max_worker_processes;
extern PGDLLIMPORT int max_parallel_workers;
 
extern PGDLLIMPORT int commit_timestamp_buffers;
extern PGDLLIMPORT int multixact_member_buffers;
extern PGDLLIMPORT int multixact_offset_buffers;
extern PGDLLIMPORT int notify_buffers;
extern PGDLLIMPORT int serializable_buffers;
extern PGDLLIMPORT int subtransaction_buffers;
extern PGDLLIMPORT int transaction_buffers;
 
extern PGDLLIMPORT int MyProcPid;
extern PGDLLIMPORT pg_time_t MyStartTime;
extern PGDLLIMPORT TimestampTz MyStartTimestamp;
extern PGDLLIMPORT struct Port *MyProcPort;
extern PGDLLIMPORT struct Latch *MyLatch;
extern PGDLLIMPORT char MyCancelKey[];
extern PGDLLIMPORT int MyCancelKeyLength;
extern PGDLLIMPORT int MyPMChildSlot;
 
extern PGDLLIMPORT char OutputFileName[];
extern PGDLLIMPORT char my_exec_path[];
extern PGDLLIMPORT char pkglib_path[];
 
#ifdef EXEC_BACKEND
extern PGDLLIMPORT char postgres_exec_path[];
#endif
 
extern PGDLLIMPORT Oid MyDatabaseId;
 
extern PGDLLIMPORT Oid MyDatabaseTableSpace;
 
extern PGDLLIMPORT bool MyDatabaseHasLoginEventTriggers;
 
/*
 * Date/Time Configuration
 *
 * DateStyle defines the output formatting choice for date/time types:
 *  USE_POSTGRES_DATES specifies traditional Postgres format
 *  USE_ISO_DATES specifies ISO-compliant format
 *  USE_SQL_DATES specifies Oracle/Ingres-compliant format
 *  USE_GERMAN_DATES specifies German-style dd.mm/yyyy
 *
 * DateOrder defines the field order to be assumed when reading an
 * ambiguous date (anything not in YYYY-MM-DD format, with a four-digit
 * year field first, is taken to be ambiguous):
 *  DATEORDER_YMD specifies field order yy-mm-dd
 *  DATEORDER_DMY specifies field order dd-mm-yy ("European" convention)
 *  DATEORDER_MDY specifies field order mm-dd-yy ("US" convention)
 *
 * In the Postgres and SQL DateStyles, DateOrder also selects output field
 * order: day comes before month in DMY style, else month comes before day.
 *
 * The user-visible "DateStyle" run-time parameter subsumes both of these.
 */
 
/* valid DateStyle values */
#define USE_POSTGRES_DATES      0
#define USE_ISO_DATES           1
#define USE_SQL_DATES           2
#define USE_GERMAN_DATES        3
#define USE_XSD_DATES           4
 
/* valid DateOrder values */
#define DATEORDER_YMD           0
#define DATEORDER_DMY           1
#define DATEORDER_MDY           2
 
extern PGDLLIMPORT int DateStyle;
extern PGDLLIMPORT int DateOrder;
 
/*
 * IntervalStyles
 *   INTSTYLE_POSTGRES             Like Postgres < 8.4 when DateStyle = 'iso'
 *   INTSTYLE_POSTGRES_VERBOSE     Like Postgres < 8.4 when DateStyle != 'iso'
 *   INTSTYLE_SQL_STANDARD         SQL standard interval literals
 *   INTSTYLE_ISO_8601             ISO-8601-basic formatted intervals
 */
#define INTSTYLE_POSTGRES           0
#define INTSTYLE_POSTGRES_VERBOSE   1
#define INTSTYLE_SQL_STANDARD       2
#define INTSTYLE_ISO_8601           3
 
extern PGDLLIMPORT int IntervalStyle;
 
#define MAXTZLEN        10      /* max TZ name len, not counting tr. null */
 
extern PGDLLIMPORT bool enableFsync;
extern PGDLLIMPORT bool allowSystemTableMods;
extern PGDLLIMPORT int work_mem;
extern PGDLLIMPORT double hash_mem_multiplier;
extern PGDLLIMPORT int maintenance_work_mem;
extern PGDLLIMPORT int max_parallel_maintenance_workers;
 
/*
 * Upper and lower hard limits for the buffer access strategy ring size
 * specified by the VacuumBufferUsageLimit GUC and BUFFER_USAGE_LIMIT option
 * to VACUUM and ANALYZE.
 */
#define MIN_BAS_VAC_RING_SIZE_KB 128
#define MAX_BAS_VAC_RING_SIZE_KB (16 * 1024 * 1024)
 
extern PGDLLIMPORT int VacuumBufferUsageLimit;
extern PGDLLIMPORT int VacuumCostPageHit;
extern PGDLLIMPORT int VacuumCostPageMiss;
extern PGDLLIMPORT int VacuumCostPageDirty;
extern PGDLLIMPORT int VacuumCostLimit;
extern PGDLLIMPORT double VacuumCostDelay;
 
extern PGDLLIMPORT int VacuumCostBalance;
extern PGDLLIMPORT bool VacuumCostActive;
 
 
/* in utils/misc/stack_depth.c */
 
extern PGDLLIMPORT int max_stack_depth;
 
/* Required daylight between max_stack_depth and the kernel limit, in bytes */
#define STACK_DEPTH_SLOP (512 * 1024)
 
typedef char *pg_stack_base_t;
 
extern pg_stack_base_t set_stack_base(void);
extern void restore_stack_base(pg_stack_base_t base);
extern void check_stack_depth(void);
extern bool stack_is_too_deep(void);
extern ssize_t get_stack_depth_rlimit(void);
 
/* in tcop/utility.c */
extern void PreventCommandIfReadOnly(const char *cmdname);
extern void PreventCommandIfParallelMode(const char *cmdname);
extern void PreventCommandDuringRecovery(const char *cmdname);
 
/*****************************************************************************
 *    pdir.h --                                                              *
 *          POSTGRES directory path definitions.                             *
 *****************************************************************************/
 
/* flags to be OR'd to form sec_context */
#define SECURITY_LOCAL_USERID_CHANGE    0x0001
#define SECURITY_RESTRICTED_OPERATION   0x0002
#define SECURITY_NOFORCE_RLS            0x0004
 
extern PGDLLIMPORT char *DatabasePath;
 
/* now in utils/init/miscinit.c */
extern void InitPostmasterChild(void);
extern void InitStandaloneProcess(const char *argv0);
extern void InitProcessLocalLatch(void);
extern void SwitchToSharedLatch(void);
extern void SwitchBackToLocalLatch(void);
 
/*
 * MyBackendType indicates what kind of a backend this is.
 *
 * If you add entries, please also update the child_process_kinds array in
 * launch_backend.c.
 */
typedef enum BackendType
{
    B_INVALID = 0,
 
    /* Backends and other backend-like processes */
    B_BACKEND,
    B_DEAD_END_BACKEND,
    B_AUTOVAC_LAUNCHER,
    B_AUTOVAC_WORKER,
    B_BG_WORKER,
    B_WAL_SENDER,
    B_SLOTSYNC_WORKER,
 
    B_STANDALONE_BACKEND,
 
    /*
     * Auxiliary processes. These have PGPROC entries, but they are not
     * attached to any particular database, and cannot run transactions or
     * even take heavyweight locks. There can be only one of each of these
     * running at a time.
     *
     * If you modify these, make sure to update NUM_AUXILIARY_PROCS and the
     * glossary in the docs.
     */
    B_ARCHIVER,
    B_BG_WRITER,
    B_CHECKPOINTER,
    B_IO_WORKER,
    B_STARTUP,
    B_WAL_RECEIVER,
    B_WAL_SUMMARIZER,
    B_WAL_WRITER,
 
    /*
     * Logger is not connected to shared memory and does not have a PGPROC
     * entry.
     */
    B_LOGGER,
} BackendType;
 
#define BACKEND_NUM_TYPES (B_LOGGER + 1)
 
extern PGDLLIMPORT BackendType MyBackendType;
 
#define AmRegularBackendProcess()   (MyBackendType == B_BACKEND)
#define AmAutoVacuumLauncherProcess() (MyBackendType == B_AUTOVAC_LAUNCHER)
#define AmAutoVacuumWorkerProcess() (MyBackendType == B_AUTOVAC_WORKER)
#define AmBackgroundWorkerProcess() (MyBackendType == B_BG_WORKER)
#define AmWalSenderProcess()        (MyBackendType == B_WAL_SENDER)
#define AmLogicalSlotSyncWorkerProcess() (MyBackendType == B_SLOTSYNC_WORKER)
#define AmArchiverProcess()         (MyBackendType == B_ARCHIVER)
#define AmBackgroundWriterProcess() (MyBackendType == B_BG_WRITER)
#define AmCheckpointerProcess()     (MyBackendType == B_CHECKPOINTER)
#define AmStartupProcess()          (MyBackendType == B_STARTUP)
#define AmWalReceiverProcess()      (MyBackendType == B_WAL_RECEIVER)
#define AmWalSummarizerProcess()    (MyBackendType == B_WAL_SUMMARIZER)
#define AmWalWriterProcess()        (MyBackendType == B_WAL_WRITER)
#define AmIoWorkerProcess()         (MyBackendType == B_IO_WORKER)
 
#define AmSpecialWorkerProcess() \
    (AmAutoVacuumLauncherProcess() || \
     AmLogicalSlotSyncWorkerProcess())
 
/*
 * Backend types that are spawned by the postmaster to serve a client or
 * replication connection. These backend types have in common that they are
 * externally initiated.
 */
#define IsExternalConnectionBackend(backend_type) \
    (backend_type == B_BACKEND || backend_type == B_WAL_SENDER)
 
extern const char *GetBackendTypeDesc(BackendType backendType);
 
extern void SetDatabasePath(const char *path);
extern void checkDataDir(void);
extern void SetDataDir(const char *dir);
extern void ChangeToDataDir(void);
 
extern char *GetUserNameFromId(Oid roleid, bool noerr);
extern Oid  GetUserId(void);
extern Oid  GetOuterUserId(void);
extern Oid  GetSessionUserId(void);
extern bool GetSessionUserIsSuperuser(void);
extern Oid  GetAuthenticatedUserId(void);
extern void SetAuthenticatedUserId(Oid userid);
extern void GetUserIdAndSecContext(Oid *userid, int *sec_context);
extern void SetUserIdAndSecContext(Oid userid, int sec_context);
extern bool InLocalUserIdChange(void);
extern bool InSecurityRestrictedOperation(void);
extern bool InNoForceRLSOperation(void);
extern void GetUserIdAndContext(Oid *userid, bool *sec_def_context);
extern void SetUserIdAndContext(Oid userid, bool sec_def_context);
extern void InitializeSessionUserId(const char *rolename, Oid roleid,
                                    bool bypass_login_check);
extern void InitializeSessionUserIdStandalone(void);
extern void SetSessionAuthorization(Oid userid, bool is_superuser);
extern Oid  GetCurrentRoleId(void);
extern void SetCurrentRoleId(Oid roleid, bool is_superuser);
extern void InitializeSystemUser(const char *authn_id,
                                 const char *auth_method);
extern const char *GetSystemUser(void);
 
/* in utils/misc/superuser.c */
extern bool superuser(void);    /* current user is superuser */
extern bool superuser_arg(Oid roleid);  /* given user is superuser */
 
 
/*****************************************************************************
 *    pmod.h --                                                              *
 *          POSTGRES processing mode definitions.                            *
 *****************************************************************************/
 
/*
 * Description:
 *      There are three processing modes in POSTGRES.  They are
 * BootstrapProcessing or "bootstrap," InitProcessing or
 * "initialization," and NormalProcessing or "normal."
 *
 * The first two processing modes are used during special times. When the
 * system state indicates bootstrap processing, transactions are all given
 * transaction id "one" and are consequently guaranteed to commit. This mode
 * is used during the initial generation of template databases.
 *
 * Initialization mode: used while starting a backend, until all normal
 * initialization is complete.  Some code behaves differently when executed
 * in this mode to enable system bootstrapping.
 *
 * If a POSTGRES backend process is in normal mode, then all code may be
 * executed normally.
 */
 
typedef enum ProcessingMode
{
    BootstrapProcessing,        /* bootstrap creation of template database */
    InitProcessing,             /* initializing system */
    NormalProcessing,           /* normal processing */
} ProcessingMode;
 
extern PGDLLIMPORT ProcessingMode Mode;
 
#define IsBootstrapProcessingMode() (Mode == BootstrapProcessing)
#define IsInitProcessingMode()      (Mode == InitProcessing)
#define IsNormalProcessingMode()    (Mode == NormalProcessing)
 
#define GetProcessingMode() Mode
 
#define SetProcessingMode(mode) \
    do { \
        Assert((mode) == BootstrapProcessing || \
                  (mode) == InitProcessing || \
                  (mode) == NormalProcessing); \
        Mode = (mode); \
    } while(0)
 
 
/*****************************************************************************
 *    pinit.h --                                                             *
 *          POSTGRES initialization and cleanup definitions.                 *
 *****************************************************************************/
 
/* in utils/init/postinit.c */
/* flags for InitPostgres() */
#define INIT_PG_LOAD_SESSION_LIBS       0x0001
#define INIT_PG_OVERRIDE_ALLOW_CONNS    0x0002
#define INIT_PG_OVERRIDE_ROLE_LOGIN     0x0004
extern void pg_split_opts(char **argv, int *argcp, const char *optstr);
extern void InitializeMaxBackends(void);
extern void InitializeFastPathLocks(void);
extern void InitPostgres(const char *in_dbname, Oid dboid,
                         const char *username, Oid useroid,
                         bits32 flags,
                         char *out_dbname);
extern void BaseInit(void);
 
/* in utils/init/miscinit.c */
extern PGDLLIMPORT bool IgnoreSystemIndexes;
extern PGDLLIMPORT bool process_shared_preload_libraries_in_progress;
extern PGDLLIMPORT bool process_shared_preload_libraries_done;
extern PGDLLIMPORT bool process_shmem_requests_in_progress;
extern PGDLLIMPORT char *session_preload_libraries_string;
extern PGDLLIMPORT char *shared_preload_libraries_string;
extern PGDLLIMPORT char *local_preload_libraries_string;
 
extern void CreateDataDirLockFile(bool amPostmaster);
extern void CreateSocketLockFile(const char *socketfile, bool amPostmaster,
                                 const char *socketDir);
extern void TouchSocketLockFiles(void);
extern void AddToDataDirLockFile(int target_line, const char *str);
extern bool RecheckDataDirLockFile(void);
extern void ValidatePgVersion(const char *path);
extern void process_shared_preload_libraries(void);
extern void process_session_preload_libraries(void);
extern void process_shmem_requests(void);
extern void pg_bindtextdomain(const char *domain);
extern bool has_rolreplication(Oid roleid);
 
typedef void (*shmem_request_hook_type) (void);
extern PGDLLIMPORT shmem_request_hook_type shmem_request_hook;
 
extern Size EstimateClientConnectionInfoSpace(void);
extern void SerializeClientConnectionInfo(Size maxsize, char *start_address);
extern void RestoreClientConnectionInfo(char *conninfo);
 
/* in executor/nodeHash.c */
extern size_t get_hash_memory_limit(void);
 
#endif                          /* MISCADMIN_H */