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) 1996-2026, 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_IO_WORKER_GROW, /* I/O worker pool wants to grow */
42 : : PMSIGNAL_BACKGROUND_WORKER_CHANGE, /* background worker state change */
43 : : PMSIGNAL_START_WALRECEIVER, /* start a walreceiver */
44 : : PMSIGNAL_ADVANCE_STATE_MACHINE, /* advance postmaster's state machine */
45 : : PMSIGNAL_XLOG_IS_SHUTDOWN, /* ShutdownXLOG() completed */
46 : : } PMSignalReason;
47 : :
48 : : #define NUM_PMSIGNALS (PMSIGNAL_XLOG_IS_SHUTDOWN+1)
49 : :
50 : : /*
51 : : * Reasons why the postmaster would send SIGQUIT to its children.
52 : : */
53 : : typedef enum
54 : : {
55 : : PMQUIT_NOT_SENT = 0, /* postmaster hasn't sent SIGQUIT */
56 : : PMQUIT_FOR_CRASH, /* some other backend bought the farm */
57 : : PMQUIT_FOR_STOP, /* immediate stop was commanded */
58 : : } QuitSignalReason;
59 : :
60 : : /* PMSignalData is an opaque struct, details known only within pmsignal.c */
61 : : typedef struct PMSignalData PMSignalData;
62 : :
63 : : #ifdef EXEC_BACKEND
64 : : extern PGDLLIMPORT volatile PMSignalData *PMSignalState;
65 : : #endif
66 : :
67 : : /*
68 : : * prototypes for functions in pmsignal.c
69 : : */
70 : : extern void SendPostmasterSignal(PMSignalReason reason);
71 : : extern bool CheckPostmasterSignal(PMSignalReason reason);
72 : : extern void SetQuitSignalReason(QuitSignalReason reason);
73 : : extern QuitSignalReason GetQuitSignalReason(void);
74 : : extern void MarkPostmasterChildSlotAssigned(int slot);
75 : : extern bool MarkPostmasterChildSlotUnassigned(int slot);
76 : : extern bool IsPostmasterChildWalSender(int slot);
77 : : extern void RegisterPostmasterChildActive(void);
78 : : extern void MarkPostmasterChildWalSender(void);
79 : : extern bool PostmasterIsAliveInternal(void);
80 : : extern void PostmasterDeathSignalInit(void);
81 : :
82 : :
83 : : /*
84 : : * Do we have a way to ask for a signal on parent death?
85 : : *
86 : : * If we do, pmsignal.c will set up a signal handler, that sets a flag when
87 : : * the parent dies. Checking the flag first makes PostmasterIsAlive() a lot
88 : : * cheaper in usual case that the postmaster is alive.
89 : : */
90 : : #if (defined(HAVE_SYS_PRCTL_H) && defined(PR_SET_PDEATHSIG)) || \
91 : : (defined(HAVE_SYS_PROCCTL_H) && defined(PROC_PDEATHSIG_CTL))
92 : : #define USE_POSTMASTER_DEATH_SIGNAL
93 : : #endif
94 : :
95 : : #ifdef USE_POSTMASTER_DEATH_SIGNAL
96 : : extern PGDLLIMPORT volatile sig_atomic_t postmaster_possibly_dead;
97 : :
98 : : static inline bool
2855 tmunro@postgresql.or 99 :CBC 2936621 : PostmasterIsAlive(void)
100 : : {
101 [ + + ]: 2936621 : if (likely(!postmaster_possibly_dead))
102 : 2936342 : return true;
103 : 279 : return PostmasterIsAliveInternal();
104 : : }
105 : : #else
106 : : #define PostmasterIsAlive() PostmasterIsAliveInternal()
107 : : #endif
108 : :
109 : : #endif /* PMSIGNAL_H */
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