Age Owner TLA Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * interrupt.c
4 : * Interrupt handling routines.
5 : *
6 : * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : * IDENTIFICATION
10 : * src/backend/postmaster/interrupt.c
11 : *
12 : *-------------------------------------------------------------------------
13 : */
14 :
15 : #include "postgres.h"
16 :
17 : #include <unistd.h>
18 :
19 : #include "miscadmin.h"
20 : #include "postmaster/interrupt.h"
21 : #include "storage/ipc.h"
22 : #include "storage/latch.h"
23 : #include "storage/procsignal.h"
24 : #include "utils/guc.h"
25 : #include "utils/memutils.h"
26 :
27 : volatile sig_atomic_t ConfigReloadPending = false;
28 : volatile sig_atomic_t ShutdownRequestPending = false;
29 :
30 : /*
31 : * Simple interrupt handler for main loops of background processes.
32 : */
33 : void
1209 rhaas 34 CBC 10790 : HandleMainLoopInterrupts(void)
35 : {
1207 36 10790 : if (ProcSignalBarrierPending)
37 38 : ProcessProcSignalBarrier();
38 :
1209 39 10790 : if (ConfigReloadPending)
40 : {
41 36 : ConfigReloadPending = false;
42 36 : ProcessConfigFile(PGC_SIGHUP);
43 : }
44 :
45 10790 : if (ShutdownRequestPending)
46 352 : proc_exit(0);
47 :
48 : /* Perform logging of memory contexts of this process */
453 fujii 49 10438 : if (LogMemoryContextPending)
453 fujii 50 UBC 0 : ProcessLogMemoryContextInterrupt();
1209 rhaas 51 CBC 10438 : }
52 :
53 : /*
54 : * Simple signal handler for triggering a configuration reload.
55 : *
56 : * Normally, this handler would be used for SIGHUP. The idea is that code
57 : * which uses it would arrange to check the ConfigReloadPending flag at
58 : * convenient places inside main loops, or else call HandleMainLoopInterrupts.
59 : */
60 : void
61 304 : SignalHandlerForConfigReload(SIGNAL_ARGS)
62 : {
63 304 : int save_errno = errno;
64 :
65 304 : ConfigReloadPending = true;
66 304 : SetLatch(MyLatch);
67 :
68 304 : errno = save_errno;
69 304 : }
70 :
71 : /*
72 : * Simple signal handler for exiting quickly as if due to a crash.
73 : *
74 : * Normally, this would be used for handling SIGQUIT.
75 : */
76 : void
1209 rhaas 77 UBC 0 : SignalHandlerForCrashExit(SIGNAL_ARGS)
78 : {
79 : /*
80 : * We DO NOT want to run proc_exit() or atexit() callbacks -- we're here
81 : * because shared memory may be corrupted, so we don't want to try to
82 : * clean up our transaction. Just nail the windows shut and get out of
83 : * town. The callbacks wouldn't be safe to run from a signal handler,
84 : * anyway.
85 : *
86 : * Note we do _exit(2) not _exit(0). This is to force the postmaster into
87 : * a system reset cycle if someone sends a manual SIGQUIT to a random
88 : * backend. This is necessary precisely because we don't clean up our
89 : * shared memory state. (The "dead man switch" mechanism in pmsignal.c
90 : * should ensure the postmaster sees this as a crash, too, but no harm in
91 : * being doubly sure.)
92 : */
93 0 : _exit(2);
94 : }
95 :
96 : /*
97 : * Simple signal handler for triggering a long-running background process to
98 : * shut down and exit.
99 : *
100 : * Typically, this handler would be used for SIGTERM, but some processes use
101 : * other signals. In particular, the checkpointer exits on SIGUSR2, and the WAL
102 : * writer and the logical replication parallel apply worker exits on either
103 : * SIGINT or SIGTERM.
104 : *
105 : * ShutdownRequestPending should be checked at a convenient place within the
106 : * main loop, or else the main loop should call HandleMainLoopInterrupts.
107 : */
108 : void
1209 rhaas 109 GIC 1392 : SignalHandlerForShutdownRequest(SIGNAL_ARGS)
1209 rhaas 110 ECB : {
1209 rhaas 111 GIC 1392 : int save_errno = errno;
1209 rhaas 112 ECB :
1209 rhaas 113 GIC 1392 : ShutdownRequestPending = true;
1209 rhaas 114 CBC 1392 : SetLatch(MyLatch);
1209 rhaas 115 ECB :
1209 rhaas 116 GIC 1392 : errno = save_errno;
1209 rhaas 117 CBC 1392 : }
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