pmsignal.h File Reference

#include <signal.h>

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Macros
#define	NUM_PMSIGNALS   (PMSIGNAL_XLOG_IS_SHUTDOWN+1)
#define	PostmasterIsAlive()   PostmasterIsAliveInternal()

Typedefs
typedef struct PMSignalData	PMSignalData

Enumerations
enum	PMSignalReason {   PMSIGNAL_RECOVERY_STARTED , PMSIGNAL_RECOVERY_CONSISTENT , PMSIGNAL_BEGIN_HOT_STANDBY , PMSIGNAL_ROTATE_LOGFILE ,   PMSIGNAL_START_AUTOVAC_LAUNCHER , PMSIGNAL_START_AUTOVAC_WORKER , PMSIGNAL_BACKGROUND_WORKER_CHANGE , PMSIGNAL_START_WALRECEIVER ,   PMSIGNAL_ADVANCE_STATE_MACHINE , PMSIGNAL_XLOG_IS_SHUTDOWN }
enum	QuitSignalReason { PMQUIT_NOT_SENT = 0 , PMQUIT_FOR_CRASH , PMQUIT_FOR_STOP }

Functions
Size	PMSignalShmemSize (void)
void	PMSignalShmemInit (void)
void	SendPostmasterSignal (PMSignalReason reason)
bool	CheckPostmasterSignal (PMSignalReason reason)
void	SetQuitSignalReason (QuitSignalReason reason)
QuitSignalReason	GetQuitSignalReason (void)
void	MarkPostmasterChildSlotAssigned (int slot)
bool	MarkPostmasterChildSlotUnassigned (int slot)
bool	IsPostmasterChildWalSender (int slot)
void	RegisterPostmasterChildActive (void)
void	MarkPostmasterChildWalSender (void)
bool	PostmasterIsAliveInternal (void)
void	PostmasterDeathSignalInit (void)

Macro Definition Documentation

NUM_PMSIGNALS

#define NUM_PMSIGNALS   (PMSIGNAL_XLOG_IS_SHUTDOWN+1)

Definition at line 47 of file pmsignal.h.

PostmasterIsAlive

#define PostmasterIsAlive

(

)

PostmasterIsAliveInternal()

Definition at line 107 of file pmsignal.h.

Typedef Documentation

PMSignalData

typedef struct PMSignalData PMSignalData

Definition at line 60 of file pmsignal.h.

Enumeration Type Documentation

PMSignalReason

enum PMSignalReason

Enumerator
PMSIGNAL_RECOVERY_STARTED
PMSIGNAL_RECOVERY_CONSISTENT
PMSIGNAL_BEGIN_HOT_STANDBY
PMSIGNAL_ROTATE_LOGFILE
PMSIGNAL_START_AUTOVAC_LAUNCHER
PMSIGNAL_START_AUTOVAC_WORKER
PMSIGNAL_BACKGROUND_WORKER_CHANGE
PMSIGNAL_START_WALRECEIVER
PMSIGNAL_ADVANCE_STATE_MACHINE
PMSIGNAL_XLOG_IS_SHUTDOWN

Definition at line 33 of file pmsignal.h.

{
    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;

QuitSignalReason

enum QuitSignalReason

Enumerator
PMQUIT_NOT_SENT
PMQUIT_FOR_CRASH
PMQUIT_FOR_STOP

Definition at line 52 of file pmsignal.h.

{
    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;

Function Documentation

CheckPostmasterSignal()

bool CheckPostmasterSignal ( PMSignalReason  reason )

extern

Definition at line 182 of file pmsignal.c.

{
    /* Careful here --- don't clear flag if we haven't seen it set */
    if (PMSignalState->PMSignalFlags[reason])
    {
        PMSignalState->PMSignalFlags[reason] = false;
        return true;
    }
    return false;
}

References PMSignalData::PMSignalFlags, and PMSignalState.

Referenced by process_pm_pmsignal().

GetQuitSignalReason()

QuitSignalReason GetQuitSignalReason ( void  )

extern

Definition at line 213 of file pmsignal.c.

{
    /* This is called in signal handlers, so be extra paranoid. */
    if (!IsUnderPostmaster || PMSignalState == NULL)
        return PMQUIT_NOT_SENT;
    return PMSignalState->sigquit_reason;
}

References fb(), IsUnderPostmaster, PMQUIT_NOT_SENT, PMSignalState, and PMSignalData::sigquit_reason.

Referenced by quickdie().

IsPostmasterChildWalSender()

bool IsPostmasterChildWalSender ( int  slot )

extern

Definition at line 271 of file pmsignal.c.

{
    Assert(slot > 0 && slot <= num_child_flags);
    slot--;
 
    if (PMSignalState->PMChildFlags[slot] == PM_CHILD_WALSENDER)
        return true;
    else
        return false;
}

References Assert, num_child_flags, PM_CHILD_WALSENDER, PMSignalData::PMChildFlags, and PMSignalState.

Referenced by CountChildren(), and SignalChildren().

MarkPostmasterChildSlotAssigned()

void MarkPostmasterChildSlotAssigned ( int  slot )

extern

Definition at line 230 of file pmsignal.c.

{
    Assert(slot > 0 && slot <= num_child_flags);
    slot--;
 
    if (PMSignalState->PMChildFlags[slot] != PM_CHILD_UNUSED)
        elog(FATAL, "postmaster child slot is already in use");
 
    PMSignalState->PMChildFlags[slot] = PM_CHILD_ASSIGNED;
}

References Assert, elog, FATAL, num_child_flags, PM_CHILD_ASSIGNED, PM_CHILD_UNUSED, PMSignalData::PMChildFlags, and PMSignalState.

Referenced by AssignPostmasterChildSlot().

MarkPostmasterChildSlotUnassigned()

bool MarkPostmasterChildSlotUnassigned ( int  slot )

extern

Definition at line 249 of file pmsignal.c.

{
    bool        result;
 
    Assert(slot > 0 && slot <= num_child_flags);
    slot--;
 
    /*
     * Note: the slot state might already be unused, because the logic in
     * postmaster.c is such that this might get called twice when a child
     * crashes.  So we don't try to Assert anything about the state.
     */
    result = (PMSignalState->PMChildFlags[slot] == PM_CHILD_ASSIGNED);
    PMSignalState->PMChildFlags[slot] = PM_CHILD_UNUSED;
    return result;
}

References Assert, num_child_flags, PM_CHILD_ASSIGNED, PM_CHILD_UNUSED, PMSignalData::PMChildFlags, and PMSignalState.

Referenced by ReleasePostmasterChildSlot().

MarkPostmasterChildWalSender()

void MarkPostmasterChildWalSender ( void  )

extern

Definition at line 309 of file pmsignal.c.

{
    int         slot = MyPMChildSlot;
 
    Assert(am_walsender);
 
    Assert(slot > 0 && slot <= PMSignalState->num_child_flags);
    slot--;
    Assert(PMSignalState->PMChildFlags[slot] == PM_CHILD_ACTIVE);
    PMSignalState->PMChildFlags[slot] = PM_CHILD_WALSENDER;
}

References am_walsender, Assert, fb(), MyPMChildSlot, num_child_flags, PM_CHILD_ACTIVE, PM_CHILD_WALSENDER, PMSignalData::PMChildFlags, and PMSignalState.

Referenced by InitWalSender().

PMSignalShmemInit()

void PMSignalShmemInit ( void  )

extern

Definition at line 145 of file pmsignal.c.

{
    bool        found;
 
    PMSignalState = (PMSignalData *)
        ShmemInitStruct("PMSignalState", PMSignalShmemSize(), &found);
 
    if (!found)
    {
        /* initialize all flags to zeroes */
        MemSet(unvolatize(PMSignalData *, PMSignalState), 0, PMSignalShmemSize());
        num_child_flags = MaxLivePostmasterChildren();
        PMSignalState->num_child_flags = num_child_flags;
    }
}

References MaxLivePostmasterChildren(), MemSet, PMSignalData::num_child_flags, num_child_flags, PMSignalShmemSize(), PMSignalState, ShmemInitStruct(), and unvolatize.

Referenced by CreateOrAttachShmemStructs().

PMSignalShmemSize()

Size PMSignalShmemSize ( void  )

extern

Definition at line 130 of file pmsignal.c.

{
    Size        size;
 
    size = offsetof(PMSignalData, PMChildFlags);
    size = add_size(size, mul_size(MaxLivePostmasterChildren(),
                                   sizeof(sig_atomic_t)));
 
    return size;
}

References add_size(), fb(), MaxLivePostmasterChildren(), and mul_size().

Referenced by CalculateShmemSize(), and PMSignalShmemInit().

PostmasterDeathSignalInit()

void PostmasterDeathSignalInit ( void  )

extern

Definition at line 407 of file pmsignal.c.

{
#ifdef USE_POSTMASTER_DEATH_SIGNAL
    int         signum = POSTMASTER_DEATH_SIGNAL;
 
    /* Register our signal handler. */
    pqsignal(signum, postmaster_death_handler);
 
    /* Request a signal on parent exit. */
#if defined(PR_SET_PDEATHSIG)
    if (prctl(PR_SET_PDEATHSIG, signum) < 0)
        elog(ERROR, "could not request parent death signal: %m");
#elif defined(PROC_PDEATHSIG_CTL)
    if (procctl(P_PID, 0, PROC_PDEATHSIG_CTL, &signum) < 0)
        elog(ERROR, "could not request parent death signal: %m");
#else
#error "USE_POSTMASTER_DEATH_SIGNAL set, but there is no mechanism to request the signal"
#endif
 
    /*
     * Just in case the parent was gone already and we missed it, we'd better
     * check the slow way on the first call.
     */
    postmaster_possibly_dead = true;
#endif                          /* USE_POSTMASTER_DEATH_SIGNAL */
}

References elog, ERROR, fb(), and pqsignal.

Referenced by InitPostmasterChild().

PostmasterIsAliveInternal()

bool PostmasterIsAliveInternal ( void  )

extern

Definition at line 346 of file pmsignal.c.

{
#ifdef USE_POSTMASTER_DEATH_SIGNAL
    /*
     * Reset the flag before checking, so that we don't miss a signal if
     * postmaster dies right after the check.  If postmaster was indeed dead,
     * we'll re-arm it before returning to caller.
     */
    postmaster_possibly_dead = false;
#endif
 
#ifndef WIN32
    {
        char        c;
        ssize_t     rc;
 
        rc = read(postmaster_alive_fds[POSTMASTER_FD_WATCH], &c, 1);
 
        /*
         * In the usual case, the postmaster is still alive, and there is no
         * data in the pipe.
         */
        if (rc < 0 && (errno == EAGAIN || errno == EWOULDBLOCK))
            return true;
        else
        {
            /*
             * Postmaster is dead, or something went wrong with the read()
             * call.
             */
 
#ifdef USE_POSTMASTER_DEATH_SIGNAL
            postmaster_possibly_dead = true;
#endif
 
            if (rc < 0)
                elog(FATAL, "read on postmaster death monitoring pipe failed: %m");
            else if (rc > 0)
                elog(FATAL, "unexpected data in postmaster death monitoring pipe");
 
            return false;
        }
    }
 
#else                           /* WIN32 */
    if (WaitForSingleObject(PostmasterHandle, 0) == WAIT_TIMEOUT)
        return true;
    else
    {
#ifdef USE_POSTMASTER_DEATH_SIGNAL
        postmaster_possibly_dead = true;
#endif
        return false;
    }
#endif                          /* WIN32 */
}

References EAGAIN, elog, EWOULDBLOCK, FATAL, fb(), postmaster_alive_fds, POSTMASTER_FD_WATCH, and read.

Referenced by WaitEventSetWaitBlock().

RegisterPostmasterChildActive()

void RegisterPostmasterChildActive ( void  )

extern

Definition at line 290 of file pmsignal.c.

{
    int         slot = MyPMChildSlot;
 
    Assert(slot > 0 && slot <= PMSignalState->num_child_flags);
    slot--;
    Assert(PMSignalState->PMChildFlags[slot] == PM_CHILD_ASSIGNED);
    PMSignalState->PMChildFlags[slot] = PM_CHILD_ACTIVE;
 
    /* Arrange to clean up at exit. */
    on_shmem_exit(MarkPostmasterChildInactive, 0);
}

References Assert, fb(), MarkPostmasterChildInactive(), MyPMChildSlot, num_child_flags, on_shmem_exit(), PM_CHILD_ACTIVE, PM_CHILD_ASSIGNED, PMSignalData::PMChildFlags, and PMSignalState.

Referenced by InitAuxiliaryProcess(), and InitProcess().

SendPostmasterSignal()

void SendPostmasterSignal ( PMSignalReason  reason )

extern

Definition at line 165 of file pmsignal.c.

{
    /* If called in a standalone backend, do nothing */
    if (!IsUnderPostmaster)
        return;
    /* Atomically set the proper flag */
    PMSignalState->PMSignalFlags[reason] = true;
    /* Send signal to postmaster */
    kill(PostmasterPid, SIGUSR1);
}

References IsUnderPostmaster, kill, PMSignalData::PMSignalFlags, PMSignalState, PostmasterPid, and SIGUSR1.

Referenced by AutoVacLauncherMain(), CheckpointerMain(), CheckRecoveryConsistency(), do_start_worker(), GetNewMultiXactId(), GetNewTransactionId(), InitWalSender(), PerformWalRecovery(), pg_rotate_logfile(), RegisterDynamicBackgroundWorker(), RequestXLogStreaming(), SetMultiXactIdLimit(), SetTransactionIdLimit(), TerminateBackgroundWorker(), and TerminateBackgroundWorkersForDatabase().

SetQuitSignalReason()

void SetQuitSignalReason ( QuitSignalReason  reason )

extern

Definition at line 202 of file pmsignal.c.

{
    PMSignalState->sigquit_reason = reason;
}

References PMSignalState, and PMSignalData::sigquit_reason.

Referenced by HandleFatalError(), and process_pm_shutdown_request().