#include <signal.h>

Include dependency graph for pmsignal.h:

This graph shows which files directly or indirectly include this file:

Macros
#define	PostmasterIsAlive() PostmasterIsAliveInternal()

Typedefs
typedef struct PMSignalData	PMSignalData

Enumerations
enum	PMSignalReason { PMSIGNAL_RECOVERY_STARTED , 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 , NUM_PMSIGNALS }

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)

int	AssignPostmasterChildSlot (void)

bool	ReleasePostmasterChildSlot (int slot)

bool	IsPostmasterChildWalSender (int slot)

void	MarkPostmasterChildActive (void)

void	MarkPostmasterChildInactive (void)

void	MarkPostmasterChildWalSender (void)

bool	PostmasterIsAliveInternal (void)

void	PostmasterDeathSignalInit (void)

Macro Definition Documentation

◆ PostmasterIsAlive

#define PostmasterIsAlive ( ) PostmasterIsAliveInternal()

Definition at line 102 of file pmsignal.h.

Typedef Documentation

◆ PMSignalData

typedef struct PMSignalData PMSignalData

Definition at line 1 of file pmsignal.h.

Enumeration Type Documentation

◆ PMSignalReason

enum PMSignalReason

Enumerator
PMSIGNAL_RECOVERY_STARTED
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
NUM_PMSIGNALS

Definition at line 33 of file pmsignal.h.

 {
     PMSIGNAL_RECOVERY_STARTED,  /* recovery has started */
     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 */
  
     NUM_PMSIGNALS               /* Must be last value of enum! */
 } PMSignalReason;

◆ QuitSignalReason

enum QuitSignalReason

Enumerator
PMQUIT_NOT_SENT
PMQUIT_FOR_CRASH
PMQUIT_FOR_STOP

Definition at line 50 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

◆ AssignPostmasterChildSlot()

int AssignPostmasterChildSlot ( void )

Definition at line 219 of file pmsignal.c.

 {
     int         slot = PMSignalState->next_child_flag;
     int         n;
  
     /*
      * Scan for a free slot.  We track the last slot assigned so as not to
      * waste time repeatedly rescanning low-numbered slots.
      */
     for (n = PMSignalState->num_child_flags; n > 0; n--)
     {
         if (--slot < 0)
             slot = PMSignalState->num_child_flags - 1;
         if (PMSignalState->PMChildFlags[slot] == PM_CHILD_UNUSED)
         {
             PMSignalState->PMChildFlags[slot] = PM_CHILD_ASSIGNED;
             PMSignalState->next_child_flag = slot;
             return slot + 1;
         }
     }
  
     /* Out of slots ... should never happen, else postmaster.c messed up */
     elog(FATAL, "no free slots in PMChildFlags array");
     return 0;                   /* keep compiler quiet */
 }

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

Referenced by assign_backendlist_entry(), BackendStartup(), and StartAutovacuumWorker().

◆ CheckPostmasterSignal()

bool CheckPostmasterSignal ( PMSignalReason reason )

Definition at line 170 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 sigusr1_handler().

◆ GetQuitSignalReason()

QuitSignalReason GetQuitSignalReason ( void )

Definition at line 201 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 IsUnderPostmaster, PMQUIT_NOT_SENT, PMSignalState, and PMSignalData::sigquit_reason.

Referenced by quickdie().

◆ IsPostmasterChildWalSender()

bool IsPostmasterChildWalSender ( int slot )

Definition at line 275 of file pmsignal.c.

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

References Assert(), PM_CHILD_WALSENDER, PMSignalData::PMChildFlags, and PMSignalState.

Referenced by CountChildren(), and SignalSomeChildren().

◆ MarkPostmasterChildActive()

void MarkPostmasterChildActive ( void )

Definition at line 291 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;
 }

References Assert(), MyPMChildSlot, PM_CHILD_ACTIVE, PM_CHILD_ASSIGNED, PMSignalData::PMChildFlags, and PMSignalState.

Referenced by InitProcess().

◆ MarkPostmasterChildInactive()

void MarkPostmasterChildInactive ( void )

Definition at line 324 of file pmsignal.c.

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

References Assert(), MyPMChildSlot, PM_CHILD_ACTIVE, PM_CHILD_ASSIGNED, PM_CHILD_WALSENDER, PMSignalData::PMChildFlags, and PMSignalState.

Referenced by ProcKill().

◆ MarkPostmasterChildWalSender()

void MarkPostmasterChildWalSender ( void )

Definition at line 307 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(), MyPMChildSlot, PM_CHILD_ACTIVE, PM_CHILD_WALSENDER, PMSignalData::PMChildFlags, and PMSignalState.

◆ PMSignalShmemInit()

void PMSignalShmemInit ( void )

Definition at line 134 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());
         PMSignalState->num_child_flags = MaxLivePostmasterChildren();
     }
 }

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

Referenced by CreateSharedMemoryAndSemaphores().

◆ PMSignalShmemSize()

Size PMSignalShmemSize ( void )

Definition at line 119 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(), MaxLivePostmasterChildren(), mul_size(), and offsetof.

Referenced by CalculateShmemSize(), and PMSignalShmemInit().

◆ PostmasterDeathSignalInit()

void PostmasterDeathSignalInit ( void )

Definition at line 405 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, and pqsignal().

Referenced by InitPostmasterChild().

◆ PostmasterIsAliveInternal()

bool PostmasterIsAliveInternal ( void )

Definition at line 344 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, postmaster_alive_fds, POSTMASTER_FD_WATCH, and read.

◆ ReleasePostmasterChildSlot()

bool ReleasePostmasterChildSlot ( int slot )

Definition at line 253 of file pmsignal.c.

 {
     bool        result;
  
     Assert(slot > 0 && slot <= PMSignalState->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(), PM_CHILD_ASSIGNED, PM_CHILD_UNUSED, PMSignalData::PMChildFlags, and PMSignalState.

Referenced by BackendStartup(), CleanupBackend(), CleanupBackgroundWorker(), do_start_bgworker(), HandleChildCrash(), and StartAutovacuumWorker().

◆ SendPostmasterSignal()

void SendPostmasterSignal ( PMSignalReason reason )

Definition at line 153 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(), CheckRecoveryConsistency(), do_start_worker(), GetNewMultiXactId(), GetNewTransactionId(), PerformWalRecovery(), pg_rotate_logfile(), pg_rotate_logfile_v2(), RegisterDynamicBackgroundWorker(), RequestXLogStreaming(), SetMultiXactIdLimit(), SetTransactionIdLimit(), and TerminateBackgroundWorker().

◆ SetQuitSignalReason()

void SetQuitSignalReason ( QuitSignalReason reason )

Definition at line 190 of file pmsignal.c.

 {
     PMSignalState->sigquit_reason = reason;
 }

References PMSignalState, and PMSignalData::sigquit_reason.

Referenced by HandleChildCrash(), and pmdie().

Macros

Typedefs

Enumerations

Functions