/*-------------------------------------------------------------------------

 *

 * pmsignal.h

 *    routines for signaling between the postmaster and its child processes

 *

 *

 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group

 * Portions Copyright (c) 1994, Regents of the University of California

 *

 * src/include/storage/pmsignal.h

 *

 *-------------------------------------------------------------------------

 */

#ifndef PMSIGNAL_H

#define PMSIGNAL_H

#include <signal.h>

#ifdef HAVE_SYS_PRCTL_H

#include <sys/prctl.h>

#endif

#ifdef HAVE_SYS_PROCCTL_H

#include <sys/procctl.h>

#endif

/*

 * Reasons for signaling the postmaster.  We can cope with simultaneous

 * signals for different reasons.  If the same reason is signaled multiple

 * times in quick succession, however, the postmaster is likely to observe

 * only one notification of it.  This is okay for the present uses.

 */

typedef enum

{

  PMSIGNAL_RECOVERY_STARTED,  /* recovery has started */

  PMSIGNAL_RECOVERY_CONSISTENT, /* recovery has reached consistent state */

  PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */

  PMSIGNAL_ROTATE_LOGFILE,  /* send SIGUSR1 to syslogger to rotate logfile */

  PMSIGNAL_START_AUTOVAC_LAUNCHER,  /* start an autovacuum launcher */

  PMSIGNAL_START_AUTOVAC_WORKER,  /* start an autovacuum worker */

  PMSIGNAL_BACKGROUND_WORKER_CHANGE,  /* background worker state change */

  PMSIGNAL_START_WALRECEIVER, /* start a walreceiver */

  PMSIGNAL_ADVANCE_STATE_MACHINE, /* advance postmaster's state machine */

  PMSIGNAL_XLOG_IS_SHUTDOWN,  /* ShutdownXLOG() completed */

} PMSignalReason;

#define NUM_PMSIGNALS (PMSIGNAL_XLOG_IS_SHUTDOWN+1)

/*

 * Reasons why the postmaster would send SIGQUIT to its children.

 */

typedef enum

{

  PMQUIT_NOT_SENT = 0,    /* postmaster hasn't sent SIGQUIT */

  PMQUIT_FOR_CRASH,     /* some other backend bought the farm */

  PMQUIT_FOR_STOP,      /* immediate stop was commanded */

} QuitSignalReason;

/* PMSignalData is an opaque struct, details known only within pmsignal.c */

typedef struct PMSignalData PMSignalData;

#ifdef EXEC_BACKEND

extern PGDLLIMPORT volatile PMSignalData *PMSignalState;

#endif

/*

 * prototypes for functions in pmsignal.c

 */

extern Size PMSignalShmemSize(void);

extern void PMSignalShmemInit(void);

extern void SendPostmasterSignal(PMSignalReason reason);

extern bool CheckPostmasterSignal(PMSignalReason reason);

extern void SetQuitSignalReason(QuitSignalReason reason);

extern QuitSignalReason GetQuitSignalReason(void);

extern void MarkPostmasterChildSlotAssigned(int slot);

extern bool MarkPostmasterChildSlotUnassigned(int slot);

extern bool IsPostmasterChildWalSender(int slot);

extern void RegisterPostmasterChildActive(void);

extern void MarkPostmasterChildWalSender(void);

extern bool PostmasterIsAliveInternal(void);

extern void PostmasterDeathSignalInit(void);

/*

 * Do we have a way to ask for a signal on parent death?

 *

 * If we do, pmsignal.c will set up a signal handler, that sets a flag when

 * the parent dies.  Checking the flag first makes PostmasterIsAlive() a lot

 * cheaper in usual case that the postmaster is alive.

 */

#if (defined(HAVE_SYS_PRCTL_H) && defined(PR_SET_PDEATHSIG)) || \

  (defined(HAVE_SYS_PROCCTL_H) && defined(PROC_PDEATHSIG_CTL))

#define USE_POSTMASTER_DEATH_SIGNAL

#endif

#ifdef USE_POSTMASTER_DEATH_SIGNAL

extern PGDLLIMPORT volatile sig_atomic_t postmaster_possibly_dead;

static inline bool

PostmasterIsAlive(void)

{

  if (likely(!postmaster_possibly_dead))

    return true;

  return PostmasterIsAliveInternal();

}

Unexecuted instantiation: multixact.c:PostmasterIsAlive

Unexecuted instantiation: varsup.c:PostmasterIsAlive

Unexecuted instantiation: xlogrecovery.c:PostmasterIsAlive

Unexecuted instantiation: vacuum.c:PostmasterIsAlive

Unexecuted instantiation: autovacuum.c:PostmasterIsAlive

Unexecuted instantiation: bgworker.c:PostmasterIsAlive

Unexecuted instantiation: checkpointer.c:PostmasterIsAlive

Unexecuted instantiation: pgarch.c:PostmasterIsAlive

Unexecuted instantiation: pmchild.c:PostmasterIsAlive

Unexecuted instantiation: postmaster.c:PostmasterIsAlive

Unexecuted instantiation: startup.c:PostmasterIsAlive

Unexecuted instantiation: walreceiverfuncs.c:PostmasterIsAlive

Unexecuted instantiation: walsender.c:PostmasterIsAlive

Unexecuted instantiation: ipci.c:PostmasterIsAlive

Unexecuted instantiation: pmsignal.c:PostmasterIsAlive

Unexecuted instantiation: signalfuncs.c:PostmasterIsAlive

Unexecuted instantiation: waiteventset.c:PostmasterIsAlive

Unexecuted instantiation: proc.c:PostmasterIsAlive

Unexecuted instantiation: postgres.c:PostmasterIsAlive

Unexecuted instantiation: miscinit.c:PostmasterIsAlive

#else

#define PostmasterIsAlive() PostmasterIsAliveInternal()

#endif

#endif              /* PMSIGNAL_H */