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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 <signal.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(). * * 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 bool InterruptPending; extern PGDLLIMPORT volatile bool QueryCancelPending; extern PGDLLIMPORT volatile bool ProcDiePending; extern PGDLLIMPORT volatile bool IdleInTransactionSessionTimeoutPending; extern PGDLLIMPORT volatile sig_atomic_t ConfigReloadPending; 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); /* Test whether an interrupt is pending */ #ifndef WIN32 #define INTERRUPTS_PENDING_CONDITION() \ (InterruptPending) #else #define INTERRUPTS_PENDING_CONDITION() \ (UNBLOCKED_SIGNAL_QUEUE() ? pgwin32_dispatch_queued_signals() : 0, \ 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 bool IsPostmasterEnvironment; extern PGDLLIMPORT bool IsUnderPostmaster; extern bool IsBackgroundWorker; extern PGDLLIMPORT bool IsBinaryUpgrade; extern PGDLLIMPORT bool ExitOnAnyError; extern PGDLLIMPORT char *DataDir; extern PGDLLIMPORT int NBuffers; extern PGDLLIMPORT int MaxBackends; extern PGDLLIMPORT int MaxConnections; extern PGDLLIMPORT 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 PGDLLIMPORT bool allowSystemTableMods; extern PGDLLIMPORT int work_mem; extern PGDLLIMPORT int maintenance_work_mem; extern PGDLLIMPORT int replacement_sort_tuples; 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); extern void PostgresSigHupHandler(SIGNAL_ARGS); /* 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 */