106 lines
3.4 KiB
C
106 lines
3.4 KiB
C
/*-------------------------------------------------------------------------
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*
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* pmsignal.h
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* routines for signaling between the postmaster and its child processes
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*
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*
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* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/storage/pmsignal.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef PMSIGNAL_H
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#define PMSIGNAL_H
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#include <signal.h>
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#ifdef HAVE_SYS_PRCTL_H
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#include "sys/prctl.h"
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#endif
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#ifdef HAVE_SYS_PROCCTL_H
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#include "sys/procctl.h"
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#endif
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/*
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* Reasons for signaling the postmaster. We can cope with simultaneous
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* signals for different reasons. If the same reason is signaled multiple
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* times in quick succession, however, the postmaster is likely to observe
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* only one notification of it. This is okay for the present uses.
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*/
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typedef enum
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{
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PMSIGNAL_RECOVERY_STARTED, /* recovery has started */
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PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
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PMSIGNAL_ROTATE_LOGFILE, /* send SIGUSR1 to syslogger to rotate logfile */
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PMSIGNAL_START_AUTOVAC_LAUNCHER, /* start an autovacuum launcher */
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PMSIGNAL_START_AUTOVAC_WORKER, /* start an autovacuum worker */
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PMSIGNAL_BACKGROUND_WORKER_CHANGE, /* background worker state change */
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PMSIGNAL_START_WALRECEIVER, /* start a walreceiver */
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PMSIGNAL_ADVANCE_STATE_MACHINE, /* advance postmaster's state machine */
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NUM_PMSIGNALS /* Must be last value of enum! */
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} PMSignalReason;
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/*
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* Reasons why the postmaster would send SIGQUIT to its children.
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*/
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typedef enum
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{
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PMQUIT_NOT_SENT = 0, /* postmaster hasn't sent SIGQUIT */
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PMQUIT_FOR_CRASH, /* some other backend bought the farm */
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PMQUIT_FOR_STOP, /* immediate stop was commanded */
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} QuitSignalReason;
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/* PMSignalData is an opaque struct, details known only within pmsignal.c */
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typedef struct PMSignalData PMSignalData;
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/*
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* prototypes for functions in pmsignal.c
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*/
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extern Size PMSignalShmemSize(void);
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extern void PMSignalShmemInit(void);
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extern void SendPostmasterSignal(PMSignalReason reason);
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extern bool CheckPostmasterSignal(PMSignalReason reason);
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extern void SetQuitSignalReason(QuitSignalReason reason);
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extern QuitSignalReason GetQuitSignalReason(void);
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extern int AssignPostmasterChildSlot(void);
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extern bool ReleasePostmasterChildSlot(int slot);
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extern bool IsPostmasterChildWalSender(int slot);
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extern void MarkPostmasterChildActive(void);
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extern void MarkPostmasterChildInactive(void);
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extern void MarkPostmasterChildWalSender(void);
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extern bool PostmasterIsAliveInternal(void);
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extern void PostmasterDeathSignalInit(void);
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/*
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* Do we have a way to ask for a signal on parent death?
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*
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* If we do, pmsignal.c will set up a signal handler, that sets a flag when
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* the parent dies. Checking the flag first makes PostmasterIsAlive() a lot
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* cheaper in usual case that the postmaster is alive.
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*/
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#if (defined(HAVE_SYS_PRCTL_H) && defined(PR_SET_PDEATHSIG)) || \
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(defined(HAVE_SYS_PROCCTL_H) && defined(PROC_PDEATHSIG_CTL))
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#define USE_POSTMASTER_DEATH_SIGNAL
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#endif
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#ifdef USE_POSTMASTER_DEATH_SIGNAL
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extern PGDLLIMPORT volatile sig_atomic_t postmaster_possibly_dead;
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static inline bool
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PostmasterIsAlive(void)
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{
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if (likely(!postmaster_possibly_dead))
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return true;
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return PostmasterIsAliveInternal();
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}
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#else
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#define PostmasterIsAlive() PostmasterIsAliveInternal()
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#endif
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#endif /* PMSIGNAL_H */
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