LCOV - code coverage report
Current view: top level - src/include/storage - pmsignal.h (source / functions) Hit Total Coverage
Test: PostgreSQL 13devel Lines: 4 4 100.0 %
Date: 2019-11-21 13:06:38 Functions: 1 1 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * pmsignal.h
       4             :  *    routines for signaling the postmaster from its child processes
       5             :  *
       6             :  *
       7             :  * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
       8             :  * Portions Copyright (c) 1994, Regents of the University of California
       9             :  *
      10             :  * src/include/storage/pmsignal.h
      11             :  *
      12             :  *-------------------------------------------------------------------------
      13             :  */
      14             : #ifndef PMSIGNAL_H
      15             : #define PMSIGNAL_H
      16             : 
      17             : #include <signal.h>
      18             : 
      19             : #ifdef HAVE_SYS_PRCTL_H
      20             : #include "sys/prctl.h"
      21             : #endif
      22             : 
      23             : #ifdef HAVE_SYS_PROCCTL_H
      24             : #include "sys/procctl.h"
      25             : #endif
      26             : 
      27             : /*
      28             :  * Reasons for signaling the postmaster.  We can cope with simultaneous
      29             :  * signals for different reasons.  If the same reason is signaled multiple
      30             :  * times in quick succession, however, the postmaster is likely to observe
      31             :  * only one notification of it.  This is okay for the present uses.
      32             :  */
      33             : typedef enum
      34             : {
      35             :     PMSIGNAL_RECOVERY_STARTED,  /* recovery has started */
      36             :     PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
      37             :     PMSIGNAL_WAKEN_ARCHIVER,    /* send a NOTIFY signal to xlog archiver */
      38             :     PMSIGNAL_ROTATE_LOGFILE,    /* send SIGUSR1 to syslogger to rotate logfile */
      39             :     PMSIGNAL_START_AUTOVAC_LAUNCHER,    /* start an autovacuum launcher */
      40             :     PMSIGNAL_START_AUTOVAC_WORKER,  /* start an autovacuum worker */
      41             :     PMSIGNAL_BACKGROUND_WORKER_CHANGE,  /* background worker state change */
      42             :     PMSIGNAL_START_WALRECEIVER, /* start a walreceiver */
      43             :     PMSIGNAL_ADVANCE_STATE_MACHINE, /* advance postmaster's state machine */
      44             : 
      45             :     NUM_PMSIGNALS               /* Must be last value of enum! */
      46             : } PMSignalReason;
      47             : 
      48             : /* PMSignalData is an opaque struct, details known only within pmsignal.c */
      49             : typedef struct PMSignalData PMSignalData;
      50             : 
      51             : /*
      52             :  * prototypes for functions in pmsignal.c
      53             :  */
      54             : extern Size PMSignalShmemSize(void);
      55             : extern void PMSignalShmemInit(void);
      56             : extern void SendPostmasterSignal(PMSignalReason reason);
      57             : extern bool CheckPostmasterSignal(PMSignalReason reason);
      58             : extern int  AssignPostmasterChildSlot(void);
      59             : extern bool ReleasePostmasterChildSlot(int slot);
      60             : extern bool IsPostmasterChildWalSender(int slot);
      61             : extern void MarkPostmasterChildActive(void);
      62             : extern void MarkPostmasterChildInactive(void);
      63             : extern void MarkPostmasterChildWalSender(void);
      64             : extern bool PostmasterIsAliveInternal(void);
      65             : extern void PostmasterDeathSignalInit(void);
      66             : 
      67             : 
      68             : /*
      69             :  * Do we have a way to ask for a signal on parent death?
      70             :  *
      71             :  * If we do, pmsignal.c will set up a signal handler, that sets a flag when
      72             :  * the parent dies.  Checking the flag first makes PostmasterIsAlive() a lot
      73             :  * cheaper in usual case that the postmaster is alive.
      74             :  */
      75             : #if (defined(HAVE_SYS_PRCTL_H) && defined(PR_SET_PDEATHSIG)) || \
      76             :     (defined(HAVE_SYS_PROCCTL_H) && defined(PROC_PDEATHSIG_CTL))
      77             : #define USE_POSTMASTER_DEATH_SIGNAL
      78             : #endif
      79             : 
      80             : #ifdef USE_POSTMASTER_DEATH_SIGNAL
      81             : extern volatile sig_atomic_t postmaster_possibly_dead;
      82             : 
      83             : static inline bool
      84      198328 : PostmasterIsAlive(void)
      85             : {
      86      198328 :     if (likely(!postmaster_possibly_dead))
      87      198222 :         return true;
      88         106 :     return PostmasterIsAliveInternal();
      89             : }
      90             : #else
      91             : #define PostmasterIsAlive() PostmasterIsAliveInternal()
      92             : #endif
      93             : 
      94             : #endif                          /* PMSIGNAL_H */

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