src/include/storage/procsignal.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * procsignal.h
   4  *        Routines for interprocess signaling
   5  *
   6  *
   7  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
   8  * Portions Copyright (c) 1994, Regents of the University of California
   9  *
  10  * src/include/storage/procsignal.h
  11  *
  12  *-------------------------------------------------------------------------
  13  */
  14 #ifndef PROCSIGNAL_H
  15 #define PROCSIGNAL_H
  16
  17 #include "storage/procnumber.h"
  18
  19
  20 /*
  21  * Reasons for signaling a Postgres child process (a backend or an auxiliary
  22  * process, like checkpointer).  We can cope with concurrent signals for different
  23  * reasons.  However, if the same reason is signaled multiple times in quick
  24  * succession, the process is likely to observe only one notification of it.
  25  * This is okay for the present uses.
  26  *
  27  * Also, because of race conditions, it's important that all the signals be
  28  * defined so that no harm is done if a process mistakenly receives one.
  29  */
  30 typedef enum
  31 {
  32         PROCSIG_CATCHUP_INTERRUPT,      /* sinval catchup interrupt */
  33         PROCSIG_NOTIFY_INTERRUPT,       /* listen/notify interrupt */
  34         PROCSIG_PARALLEL_MESSAGE,       /* message from cooperating parallel backend */
  35         PROCSIG_WALSND_INIT_STOPPING,   /* ask walsenders to prepare for shutdown  */
  36         PROCSIG_BARRIER,                        /* global barrier interrupt  */
  37         PROCSIG_LOG_MEMORY_CONTEXT, /* ask backend to log the memory contexts */
  38         PROCSIG_PARALLEL_APPLY_MESSAGE, /* Message from parallel apply workers */
  39
  40         /* Recovery conflict reasons */
  41         PROCSIG_RECOVERY_CONFLICT_FIRST,
  42         PROCSIG_RECOVERY_CONFLICT_DATABASE = PROCSIG_RECOVERY_CONFLICT_FIRST,
  43         PROCSIG_RECOVERY_CONFLICT_TABLESPACE,
  44         PROCSIG_RECOVERY_CONFLICT_LOCK,
  45         PROCSIG_RECOVERY_CONFLICT_SNAPSHOT,
  46         PROCSIG_RECOVERY_CONFLICT_LOGICALSLOT,
  47         PROCSIG_RECOVERY_CONFLICT_BUFFERPIN,
  48         PROCSIG_RECOVERY_CONFLICT_STARTUP_DEADLOCK,
  49         PROCSIG_RECOVERY_CONFLICT_LAST = PROCSIG_RECOVERY_CONFLICT_STARTUP_DEADLOCK,
  50 } ProcSignalReason;
  51
  52 #define NUM_PROCSIGNALS (PROCSIG_RECOVERY_CONFLICT_LAST + 1)
  53
  54 typedef enum
  55 {
  56         PROCSIGNAL_BARRIER_SMGRRELEASE, /* ask smgr to close files */
  57 } ProcSignalBarrierType;
  58
  59 /*
  60  * prototypes for functions in procsignal.c
  61  */
  62 extern Size ProcSignalShmemSize(void);
  63 extern void ProcSignalShmemInit(void);
  64
  65 extern void ProcSignalInit(bool cancel_key_valid, int32 cancel_key);
  66 extern int      SendProcSignal(pid_t pid, ProcSignalReason reason,
  67                                                    ProcNumber procNumber);
  68 extern void SendCancelRequest(int backendPID, int32 cancelAuthCode);
  69
  70 extern uint64 EmitProcSignalBarrier(ProcSignalBarrierType type);
  71 extern void WaitForProcSignalBarrier(uint64 generation);
  72 extern void ProcessProcSignalBarrier(void);
  73
  74 extern void procsignal_sigusr1_handler(SIGNAL_ARGS);
  75
  76 /* ProcSignalHeader is an opaque struct, details known only within procsignal.c */
  77 typedef struct ProcSignalHeader ProcSignalHeader;
  78
  79 #ifdef EXEC_BACKEND
  80 extern PGDLLIMPORT ProcSignalHeader *ProcSignal;
  81 #endif
  82
  83 #endif                                                  /* PROCSIGNAL_H */