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) 1996-2016, 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 "pgtime.h"             /* for pg_time_t */


#define PG_BACKEND_VERSIONSTR "postgres (PostgreSQL) " PG_VERSION "\n"

#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().
 *
 * 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 bool InterruptPending;
extern PGDLLIMPORT volatile bool QueryCancelPending;
extern PGDLLIMPORT volatile bool ProcDiePending;

extern volatile bool 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);

#ifndef WIN32

#define CHECK_FOR_INTERRUPTS() \
do { \
    if (InterruptPending) \
        ProcessInterrupts(); \
} while(0)
#else                           /* WIN32 */

#define CHECK_FOR_INTERRUPTS() \
do { \
    if (UNBLOCKED_SIGNAL_QUEUE()) \
        pgwin32_dispatch_queued_signals(); \
    if (InterruptPending) \
        ProcessInterrupts(); \
} while(0)
#endif   /* WIN32 */


#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 pid_t PostmasterPid;
extern bool IsPostmasterEnvironment;
extern PGDLLIMPORT bool IsUnderPostmaster;
extern bool IsBackgroundWorker;
extern PGDLLIMPORT bool IsBinaryUpgrade;

extern bool ExitOnAnyError;

extern PGDLLIMPORT char *DataDir;

extern PGDLLIMPORT int NBuffers;
extern int  MaxBackends;
extern int  MaxConnections;
extern int  max_worker_processes;

extern PGDLLIMPORT int MyProcPid;
extern PGDLLIMPORT pg_time_t MyStartTime;
extern PGDLLIMPORT struct Port *MyProcPort;
extern PGDLLIMPORT struct Latch *MyLatch;
extern long MyCancelKey;
extern int  MyPMChildSlot;

extern char OutputFileName[];
extern PGDLLIMPORT char my_exec_path[];
extern char pkglib_path[];

#ifdef EXEC_BACKEND
extern char postgres_exec_path[];
#endif

/*
 * done in storage/backendid.h for now.
 *
 * extern BackendId    MyBackendId;
 */
extern PGDLLIMPORT Oid MyDatabaseId;

extern PGDLLIMPORT Oid MyDatabaseTableSpace;

/*
 * 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 bool enableFsync;
extern bool allowSystemTableMods;
extern PGDLLIMPORT int work_mem;
extern PGDLLIMPORT int maintenance_work_mem;

extern int  VacuumCostPageHit;
extern int  VacuumCostPageMiss;
extern int  VacuumCostPageDirty;
extern int  VacuumCostLimit;
extern int  VacuumCostDelay;

extern int  VacuumPageHit;
extern int  VacuumPageMiss;
extern int  VacuumPageDirty;

extern int  VacuumCostBalance;
extern bool VacuumCostActive;


/* in tcop/postgres.c */

#if defined(__ia64__) || defined(__ia64)
typedef struct
{
    char       *stack_base_ptr;
    char       *register_stack_base_ptr;
} pg_stack_base_t;
#else
typedef char *pg_stack_base_t;
#endif

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);

/* in tcop/utility.c */
extern void PreventCommandIfReadOnly(const char *cmdname);
extern void PreventCommandIfParallelMode(const char *cmdname);
extern void PreventCommandDuringRecovery(const char *cmdname);

/* in utils/misc/guc.c */
extern int  trace_recovery_messages;
extern int  trace_recovery(int trace_level);

/*****************************************************************************
 *    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 char *DatabasePath;

/* now in utils/init/miscinit.c */
extern void InitPostmasterChild(void);
extern void InitStandaloneProcess(const char *argv0);

extern void SetDatabasePath(const char *path);

extern char *GetUserNameFromId(Oid roleid, bool noerr);
extern Oid  GetUserId(void);
extern Oid  GetOuterUserId(void);
extern Oid  GetSessionUserId(void);
extern Oid  GetAuthenticatedUserId(void);
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 useroid);
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 SetDataDir(const char *dir);
extern void ChangeToDataDir(void);

extern void SwitchToSharedLatch(void);
extern void SwitchBackToLocalLatch(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 ProcessingMode Mode;

#define IsBootstrapProcessingMode() (Mode == BootstrapProcessing)
#define IsInitProcessingMode()      (Mode == InitProcessing)
#define IsNormalProcessingMode()    (Mode == NormalProcessing)

#define GetProcessingMode() Mode

#define SetProcessingMode(mode) \
    do { \
        AssertArg((mode) == BootstrapProcessing || \
                  (mode) == InitProcessing || \
                  (mode) == NormalProcessing); \
        Mode = (mode); \
    } while(0)


/*
 * Auxiliary-process type identifiers.  These used to be in bootstrap.h
 * but it seems saner to have them here, with the ProcessingMode stuff.
 * The MyAuxProcType global is defined and set in bootstrap.c.
 */

typedef enum
{
    NotAnAuxProcess = -1,
    CheckerProcess = 0,
    BootstrapProcess,
    StartupProcess,
    BgWriterProcess,
    CheckpointerProcess,
    WalWriterProcess,
    WalReceiverProcess,

    NUM_AUXPROCTYPES            /* Must be last! */
} AuxProcType;

extern AuxProcType MyAuxProcType;

#define AmBootstrapProcess()        (MyAuxProcType == BootstrapProcess)
#define AmStartupProcess()          (MyAuxProcType == StartupProcess)
#define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess)
#define AmCheckpointerProcess()     (MyAuxProcType == CheckpointerProcess)
#define AmWalWriterProcess()        (MyAuxProcType == WalWriterProcess)
#define AmWalReceiverProcess()      (MyAuxProcType == WalReceiverProcess)


/*****************************************************************************
 *    pinit.h --                                                             *
 *          POSTGRES initialization and cleanup definitions.                 *
 *****************************************************************************/

/* in utils/init/postinit.c */
extern void pg_split_opts(char **argv, int *argcp, const char *optstr);
extern void InitializeMaxBackends(void);
extern void InitPostgres(const char *in_dbname, Oid dboid, const char *username,
             Oid useroid, char *out_dbname);
extern void BaseInit(void);

/* in utils/init/miscinit.c */
extern bool IgnoreSystemIndexes;
extern PGDLLIMPORT bool process_shared_preload_libraries_in_progress;
extern char *session_preload_libraries_string;
extern char *shared_preload_libraries_string;
extern char *local_preload_libraries_string;

/*
 * As of 9.1, the contents of the data-directory lock file are:
 *
 * line #
 *      1   postmaster PID (or negative of a standalone backend's PID)
 *      2   data directory path
 *      3   postmaster start timestamp (time_t representation)
 *      4   port number
 *      5   first Unix socket directory path (empty if none)
 *      6   first listen_address (IP address or "*"; empty if no TCP port)
 *      7   shared memory key (not present on Windows)
 *
 * Lines 6 and up are added via AddToDataDirLockFile() after initial file
 * creation.
 *
 * The socket lock file, if used, has the same contents as lines 1-5.
 */
#define LOCK_FILE_LINE_PID          1
#define LOCK_FILE_LINE_DATA_DIR     2
#define LOCK_FILE_LINE_START_TIME   3
#define LOCK_FILE_LINE_PORT         4
#define LOCK_FILE_LINE_SOCKET_DIR   5
#define LOCK_FILE_LINE_LISTEN_ADDR  6
#define LOCK_FILE_LINE_SHMEM_KEY    7

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 pg_bindtextdomain(const char *domain);
extern bool has_rolreplication(Oid roleid);

/* in access/transam/xlog.c */
extern bool BackupInProgress(void);
extern void CancelBackup(void);

#endif   /* MISCADMIN_H */