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pidfile.h
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1/*-------------------------------------------------------------------------
2 *
3 * pidfile.h
4 * Declarations describing the data directory lock file (postmaster.pid)
5 *
6 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 * src/include/utils/pidfile.h
10 *
11 *-------------------------------------------------------------------------
12 */
13#ifndef UTILS_PIDFILE_H
14#define UTILS_PIDFILE_H
15
16/*
17 * As of Postgres 10, the contents of the data-directory lock file are:
18 *
19 * line #
20 * 1 postmaster PID (or negative of a standalone backend's PID)
21 * 2 data directory path
22 * 3 postmaster start timestamp (time_t representation)
23 * 4 port number
24 * 5 first Unix socket directory path (empty if none)
25 * 6 first listen_address (IP address or "*"; empty if no TCP port)
26 * 7 shared memory key (empty on Windows)
27 * 8 postmaster status (see values below)
28 *
29 * Lines 6 and up are added via AddToDataDirLockFile() after initial file
30 * creation; also, line 5 is initially empty and is changed after the first
31 * Unix socket is opened. Onlookers should not assume that lines 4 and up
32 * are filled in any particular order.
33 *
34 * Socket lock file(s), if used, have the same contents as lines 1-5, with
35 * line 5 being their own directory.
36 */
37#define LOCK_FILE_LINE_PID 1
38#define LOCK_FILE_LINE_DATA_DIR 2
39#define LOCK_FILE_LINE_START_TIME 3
40#define LOCK_FILE_LINE_PORT 4
41#define LOCK_FILE_LINE_SOCKET_DIR 5
42#define LOCK_FILE_LINE_LISTEN_ADDR 6
43#define LOCK_FILE_LINE_SHMEM_KEY 7
44#define LOCK_FILE_LINE_PM_STATUS 8
45
46/*
47 * The PM_STATUS line may contain one of these values. All these strings
48 * must be the same length, per comments for AddToDataDirLockFile().
49 * We pad with spaces as needed to make that true.
50 */
51#define PM_STATUS_STARTING "starting" /* still starting up */
52#define PM_STATUS_STOPPING "stopping" /* in shutdown sequence */
53#define PM_STATUS_READY "ready " /* ready for connections */
54#define PM_STATUS_STANDBY "standby " /* up, won't accept connections */
55
56#endif /* UTILS_PIDFILE_H */