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) 1996-2025, 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_RECOVERY_CONSISTENT, /* recovery has reached consistent state */
37 : : PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */
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 : : PMSIGNAL_XLOG_IS_SHUTDOWN, /* ShutdownXLOG() completed */
45 : : } PMSignalReason;
46 : :
47 : : #define NUM_PMSIGNALS (PMSIGNAL_XLOG_IS_SHUTDOWN+1)
48 : :
49 : : /*
50 : : * Reasons why the postmaster would send SIGQUIT to its children.
51 : : */
52 : : typedef enum
53 : : {
54 : : PMQUIT_NOT_SENT = 0, /* postmaster hasn't sent SIGQUIT */
55 : : PMQUIT_FOR_CRASH, /* some other backend bought the farm */
56 : : PMQUIT_FOR_STOP, /* immediate stop was commanded */
57 : : } QuitSignalReason;
58 : :
59 : : /* PMSignalData is an opaque struct, details known only within pmsignal.c */
60 : : typedef struct PMSignalData PMSignalData;
61 : :
62 : : #ifdef EXEC_BACKEND
63 : : extern PGDLLIMPORT volatile PMSignalData *PMSignalState;
64 : : #endif
65 : :
66 : : /*
67 : : * prototypes for functions in pmsignal.c
68 : : */
69 : : extern Size PMSignalShmemSize(void);
70 : : extern void PMSignalShmemInit(void);
71 : : extern void SendPostmasterSignal(PMSignalReason reason);
72 : : extern bool CheckPostmasterSignal(PMSignalReason reason);
73 : : extern void SetQuitSignalReason(QuitSignalReason reason);
74 : : extern QuitSignalReason GetQuitSignalReason(void);
75 : : extern void MarkPostmasterChildSlotAssigned(int slot);
76 : : extern bool MarkPostmasterChildSlotUnassigned(int slot);
77 : : extern bool IsPostmasterChildWalSender(int slot);
78 : : extern void RegisterPostmasterChildActive(void);
79 : : extern void MarkPostmasterChildWalSender(void);
80 : : extern bool PostmasterIsAliveInternal(void);
81 : : extern void PostmasterDeathSignalInit(void);
82 : :
83 : :
84 : : /*
85 : : * Do we have a way to ask for a signal on parent death?
86 : : *
87 : : * If we do, pmsignal.c will set up a signal handler, that sets a flag when
88 : : * the parent dies. Checking the flag first makes PostmasterIsAlive() a lot
89 : : * cheaper in usual case that the postmaster is alive.
90 : : */
91 : : #if (defined(HAVE_SYS_PRCTL_H) && defined(PR_SET_PDEATHSIG)) || \
92 : : (defined(HAVE_SYS_PROCCTL_H) && defined(PROC_PDEATHSIG_CTL))
93 : : #define USE_POSTMASTER_DEATH_SIGNAL
94 : : #endif
95 : :
96 : : #ifdef USE_POSTMASTER_DEATH_SIGNAL
97 : : extern PGDLLIMPORT volatile sig_atomic_t postmaster_possibly_dead;
98 : :
99 : : static inline bool
2614 tmunro@postgresql.or 100 :CBC 2724128 : PostmasterIsAlive(void)
101 : : {
102 [ + + ]: 2724128 : if (likely(!postmaster_possibly_dead))
103 : 2723901 : return true;
104 : 227 : return PostmasterIsAliveInternal();
105 : : }
106 : : #else
107 : : #define PostmasterIsAlive() PostmasterIsAliveInternal()
108 : : #endif
109 : :
110 : : #endif /* PMSIGNAL_H */
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