Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * pmsignal.h
4 : : * routines for signaling between the postmaster and its child processes
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/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_ROTATE_LOGFILE, /* send SIGUSR1 to syslogger to rotate logfile */
38 : : PMSIGNAL_START_AUTOVAC_LAUNCHER, /* start an autovacuum launcher */
39 : : PMSIGNAL_START_AUTOVAC_WORKER, /* start an autovacuum worker */
40 : : PMSIGNAL_BACKGROUND_WORKER_CHANGE, /* background worker state change */
41 : : PMSIGNAL_START_WALRECEIVER, /* start a walreceiver */
42 : : PMSIGNAL_ADVANCE_STATE_MACHINE, /* advance postmaster's state machine */
43 : :
44 : : NUM_PMSIGNALS /* Must be last value of enum! */
45 : : } PMSignalReason;
46 : :
47 : : /*
48 : : * Reasons why the postmaster would send SIGQUIT to its children.
49 : : */
50 : : typedef enum
51 : : {
52 : : PMQUIT_NOT_SENT = 0, /* postmaster hasn't sent SIGQUIT */
53 : : PMQUIT_FOR_CRASH, /* some other backend bought the farm */
54 : : PMQUIT_FOR_STOP, /* immediate stop was commanded */
55 : : } QuitSignalReason;
56 : :
57 : : /* PMSignalData is an opaque struct, details known only within pmsignal.c */
58 : : typedef struct PMSignalData PMSignalData;
59 : :
60 : : /*
61 : : * prototypes for functions in pmsignal.c
62 : : */
63 : : extern Size PMSignalShmemSize(void);
64 : : extern void PMSignalShmemInit(void);
65 : : extern void SendPostmasterSignal(PMSignalReason reason);
66 : : extern bool CheckPostmasterSignal(PMSignalReason reason);
67 : : extern void SetQuitSignalReason(QuitSignalReason reason);
68 : : extern QuitSignalReason GetQuitSignalReason(void);
69 : : extern int AssignPostmasterChildSlot(void);
70 : : extern bool ReleasePostmasterChildSlot(int slot);
71 : : extern bool IsPostmasterChildWalSender(int slot);
72 : : extern void MarkPostmasterChildActive(void);
73 : : extern void MarkPostmasterChildInactive(void);
74 : : extern void MarkPostmasterChildWalSender(void);
75 : : extern bool PostmasterIsAliveInternal(void);
76 : : extern void PostmasterDeathSignalInit(void);
77 : :
78 : :
79 : : /*
80 : : * Do we have a way to ask for a signal on parent death?
81 : : *
82 : : * If we do, pmsignal.c will set up a signal handler, that sets a flag when
83 : : * the parent dies. Checking the flag first makes PostmasterIsAlive() a lot
84 : : * cheaper in usual case that the postmaster is alive.
85 : : */
86 : : #if (defined(HAVE_SYS_PRCTL_H) && defined(PR_SET_PDEATHSIG)) || \
87 : : (defined(HAVE_SYS_PROCCTL_H) && defined(PROC_PDEATHSIG_CTL))
88 : : #define USE_POSTMASTER_DEATH_SIGNAL
89 : : #endif
90 : :
91 : : #ifdef USE_POSTMASTER_DEATH_SIGNAL
92 : : extern PGDLLIMPORT volatile sig_atomic_t postmaster_possibly_dead;
93 : :
94 : : static inline bool
2104 tmunro@postgresql.or 95 :CBC 2972646 : PostmasterIsAlive(void)
96 : : {
97 [ + + ]: 2972646 : if (likely(!postmaster_possibly_dead))
98 : 2972278 : return true;
99 : 368 : return PostmasterIsAliveInternal();
100 : : }
101 : : #else
102 : : #define PostmasterIsAlive() PostmasterIsAliveInternal()
103 : : #endif
104 : :
105 : : #endif /* PMSIGNAL_H */
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