1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
/*-------------------------------------------------------------------------
*
* pmsignal.h
* routines for signaling the postmaster from its child processes
*
*
* Portions Copyright (c) 1996-2020, 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_BEGIN_HOT_STANDBY, /* begin Hot Standby */
PMSIGNAL_WAKEN_ARCHIVER, /* send a NOTIFY signal to xlog archiver */
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;
/* PMSignalData is an opaque struct, details known only within pmsignal.c */
typedef struct PMSignalData PMSignalData;
/*
* 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 int AssignPostmasterChildSlot(void);
extern bool ReleasePostmasterChildSlot(int slot);
extern bool IsPostmasterChildWalSender(int slot);
extern void MarkPostmasterChildActive(void);
extern void MarkPostmasterChildInactive(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 volatile sig_atomic_t postmaster_possibly_dead;
static inline bool
PostmasterIsAlive(void)
{
if (likely(!postmaster_possibly_dead))
return true;
return PostmasterIsAliveInternal();
}
#else
#define PostmasterIsAlive() PostmasterIsAliveInternal()
#endif
#endif /* PMSIGNAL_H */
|
