1 files changed, 402 insertions, 0 deletions
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
new file mode 100644
index 0000000..0e7de26
--- /dev/null
+++ b/src/backend/postmaster/startup.c
@@ -0,0 +1,402 @@
+/*-------------------------------------------------------------------------
+ *
+ * startup.c
+ *
+ * The Startup process initialises the server and performs any recovery
+ * actions that have been specified. Notice that there is no "main loop"
+ * since the Startup process ends as soon as initialisation is complete.
+ * (in standby mode, one can think of the replay loop as a main loop,
+ * though.)
+ *
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/postmaster/startup.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <unistd.h>
+
+#include "access/xlog.h"
+#include "access/xlogrecovery.h"
+#include "access/xlogutils.h"
+#include "libpq/pqsignal.h"
+#include "miscadmin.h"
+#include "pgstat.h"
+#include "postmaster/interrupt.h"
+#include "postmaster/startup.h"
+#include "storage/ipc.h"
+#include "storage/latch.h"
+#include "storage/pmsignal.h"
+#include "storage/procsignal.h"
+#include "storage/standby.h"
+#include "utils/guc.h"
+#include "utils/memutils.h"
+#include "utils/timeout.h"
+
+
+#ifndef USE_POSTMASTER_DEATH_SIGNAL
+/*
+ * On systems that need to make a system call to find out if the postmaster has
+ * gone away, we'll do so only every Nth call to HandleStartupProcInterrupts().
+ * This only affects how long it takes us to detect the condition while we're
+ * busy replaying WAL.  Latch waits and similar which should react immediately
+ * through the usual techniques.
+ */
+#define POSTMASTER_POLL_RATE_LIMIT 1024
+#endif
+
+/*
+ * Flags set by interrupt handlers for later service in the redo loop.
+ */
+static volatile sig_atomic_t got_SIGHUP = false;
+static volatile sig_atomic_t shutdown_requested = false;
+static volatile sig_atomic_t promote_signaled = false;
+
+/*
+ * Flag set when executing a restore command, to tell SIGTERM signal handler
+ * that it's safe to just proc_exit.
+ */
+static volatile sig_atomic_t in_restore_command = false;
+
+/*
+ * Time at which the most recent startup operation started.
+ */
+static TimestampTz startup_progress_phase_start_time;
+
+/*
+ * Indicates whether the startup progress interval mentioned by the user is
+ * elapsed or not. TRUE if timeout occurred, FALSE otherwise.
+ */
+static volatile sig_atomic_t startup_progress_timer_expired = false;
+
+/*
+ * Time between progress updates for long-running startup operations.
+ */
+int			log_startup_progress_interval = 10000;	/* 10 sec */
+
+/* Signal handlers */
+static void StartupProcTriggerHandler(SIGNAL_ARGS);
+static void StartupProcSigHupHandler(SIGNAL_ARGS);
+
+/* Callbacks */
+static void StartupProcExit(int code, Datum arg);
+
+
+/* --------------------------------
+ *		signal handler routines
+ * --------------------------------
+ */
+
+/* SIGUSR2: set flag to finish recovery */
+static void
+StartupProcTriggerHandler(SIGNAL_ARGS)
+{
+	int			save_errno = errno;
+
+	promote_signaled = true;
+	WakeupRecovery();
+
+	errno = save_errno;
+}
+
+/* SIGHUP: set flag to re-read config file at next convenient time */
+static void
+StartupProcSigHupHandler(SIGNAL_ARGS)
+{
+	int			save_errno = errno;
+
+	got_SIGHUP = true;
+	WakeupRecovery();
+
+	errno = save_errno;
+}
+
+/* SIGTERM: set flag to abort redo and exit */
+static void
+StartupProcShutdownHandler(SIGNAL_ARGS)
+{
+	int			save_errno = errno;
+
+	if (in_restore_command)
+	{
+		/*
+		 * If we are in a child process (e.g., forked by system() in
+		 * RestoreArchivedFile()), we don't want to call any exit callbacks.
+		 * The parent will take care of that.
+		 */
+		if (MyProcPid == (int) getpid())
+			proc_exit(1);
+		else
+		{
+			write_stderr_signal_safe("StartupProcShutdownHandler() called in child process\n");
+			_exit(1);
+		}
+	}
+	else
+		shutdown_requested = true;
+	WakeupRecovery();
+
+	errno = save_errno;
+}
+
+/*
+ * Re-read the config file.
+ *
+ * If one of the critical walreceiver options has changed, flag xlog.c
+ * to restart it.
+ */
+static void
+StartupRereadConfig(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		tempSlot = wal_receiver_create_temp_slot;
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+	bool		tempSlotChanged = false;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	conninfoChanged = strcmp(conninfo, PrimaryConnInfo) != 0;
+	slotnameChanged = strcmp(slotname, PrimarySlotName) != 0;
+
+	/*
+	 * wal_receiver_create_temp_slot is used only when we have no slot
+	 * configured.  We do not need to track this change if it has no effect.
+	 */
+	if (!slotnameChanged && strcmp(PrimarySlotName, "") == 0)
+		tempSlotChanged = tempSlot != wal_receiver_create_temp_slot;
+	pfree(conninfo);
+	pfree(slotname);
+
+	if (conninfoChanged || slotnameChanged || tempSlotChanged)
+		StartupRequestWalReceiverRestart();
+}
+
+/* Handle various signals that might be sent to the startup process */
+void
+HandleStartupProcInterrupts(void)
+{
+#ifdef POSTMASTER_POLL_RATE_LIMIT
+	static uint32 postmaster_poll_count = 0;
+#endif
+
+	/*
+	 * Process any requests or signals received recently.
+	 */
+	if (got_SIGHUP)
+	{
+		got_SIGHUP = false;
+		StartupRereadConfig();
+	}
+
+	/*
+	 * Check if we were requested to exit without finishing recovery.
+	 */
+	if (shutdown_requested)
+		proc_exit(1);
+
+	/*
+	 * Emergency bailout if postmaster has died.  This is to avoid the
+	 * necessity for manual cleanup of all postmaster children.  Do this less
+	 * frequently on systems for which we don't have signals to make that
+	 * cheap.
+	 */
+	if (IsUnderPostmaster &&
+#ifdef POSTMASTER_POLL_RATE_LIMIT
+		postmaster_poll_count++ % POSTMASTER_POLL_RATE_LIMIT == 0 &&
+#endif
+		!PostmasterIsAlive())
+		exit(1);
+
+	/* Process barrier events */
+	if (ProcSignalBarrierPending)
+		ProcessProcSignalBarrier();
+
+	/* Perform logging of memory contexts of this process */
+	if (LogMemoryContextPending)
+		ProcessLogMemoryContextInterrupt();
+}
+
+
+/* --------------------------------
+ *		signal handler routines
+ * --------------------------------
+ */
+static void
+StartupProcExit(int code, Datum arg)
+{
+	/* Shutdown the recovery environment */
+	if (standbyState != STANDBY_DISABLED)
+		ShutdownRecoveryTransactionEnvironment();
+}
+
+
+/* ----------------------------------
+ *	Startup Process main entry point
+ * ----------------------------------
+ */
+void
+StartupProcessMain(void)
+{
+	/* Arrange to clean up at startup process exit */
+	on_shmem_exit(StartupProcExit, 0);
+
+	/*
+	 * Properly accept or ignore signals the postmaster might send us.
+	 */
+	pqsignal(SIGHUP, StartupProcSigHupHandler); /* reload config file */
+	pqsignal(SIGINT, SIG_IGN);	/* ignore query cancel */
+	pqsignal(SIGTERM, StartupProcShutdownHandler);	/* request shutdown */
+	/* SIGQUIT handler was already set up by InitPostmasterChild */
+	InitializeTimeouts();		/* establishes SIGALRM handler */
+	pqsignal(SIGPIPE, SIG_IGN);
+	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
+	pqsignal(SIGUSR2, StartupProcTriggerHandler);
+
+	/*
+	 * Reset some signals that are accepted by postmaster but not here
+	 */
+	pqsignal(SIGCHLD, SIG_DFL);
+
+	/*
+	 * Register timeouts needed for standby mode
+	 */
+	RegisterTimeout(STANDBY_DEADLOCK_TIMEOUT, StandbyDeadLockHandler);
+	RegisterTimeout(STANDBY_TIMEOUT, StandbyTimeoutHandler);
+	RegisterTimeout(STANDBY_LOCK_TIMEOUT, StandbyLockTimeoutHandler);
+
+	/*
+	 * Unblock signals (they were blocked when the postmaster forked us)
+	 */
+	sigprocmask(SIG_SETMASK, &UnBlockSig, NULL);
+
+	/*
+	 * Do what we came for.
+	 */
+	StartupXLOG();
+
+	/*
+	 * Exit normally. Exit code 0 tells postmaster that we completed recovery
+	 * successfully.
+	 */
+	proc_exit(0);
+}
+
+void
+PreRestoreCommand(void)
+{
+	/*
+	 * Set in_restore_command to tell the signal handler that we should exit
+	 * right away on SIGTERM. We know that we're at a safe point to do that.
+	 * Check if we had already received the signal, so that we don't miss a
+	 * shutdown request received just before this.
+	 */
+	in_restore_command = true;
+	if (shutdown_requested)
+		proc_exit(1);
+}
+
+void
+PostRestoreCommand(void)
+{
+	in_restore_command = false;
+}
+
+bool
+IsPromoteSignaled(void)
+{
+	return promote_signaled;
+}
+
+void
+ResetPromoteSignaled(void)
+{
+	promote_signaled = false;
+}
+
+/*
+ * Set a flag indicating that it's time to log a progress report.
+ */
+void
+startup_progress_timeout_handler(void)
+{
+	startup_progress_timer_expired = true;
+}
+
+void
+disable_startup_progress_timeout(void)
+{
+	/* Feature is disabled. */
+	if (log_startup_progress_interval == 0)
+		return;
+
+	disable_timeout(STARTUP_PROGRESS_TIMEOUT, false);
+	startup_progress_timer_expired = false;
+}
+
+/*
+ * Set the start timestamp of the current operation and enable the timeout.
+ */
+void
+enable_startup_progress_timeout(void)
+{
+	TimestampTz fin_time;
+
+	/* Feature is disabled. */
+	if (log_startup_progress_interval == 0)
+		return;
+
+	startup_progress_phase_start_time = GetCurrentTimestamp();
+	fin_time = TimestampTzPlusMilliseconds(startup_progress_phase_start_time,
+										   log_startup_progress_interval);
+	enable_timeout_every(STARTUP_PROGRESS_TIMEOUT, fin_time,
+						 log_startup_progress_interval);
+}
+
+/*
+ * A thin wrapper to first disable and then enable the startup progress
+ * timeout.
+ */
+void
+begin_startup_progress_phase(void)
+{
+	/* Feature is disabled. */
+	if (log_startup_progress_interval == 0)
+		return;
+
+	disable_startup_progress_timeout();
+	enable_startup_progress_timeout();
+}
+
+/*
+ * Report whether startup progress timeout has occurred. Reset the timer flag
+ * if it did, set the elapsed time to the out parameters and return true,
+ * otherwise return false.
+ */
+bool
+has_startup_progress_timeout_expired(long *secs, int *usecs)
+{
+	long		seconds;
+	int			useconds;
+	TimestampTz now;
+
+	/* No timeout has occurred. */
+	if (!startup_progress_timer_expired)
+		return false;
+
+	/* Calculate the elapsed time. */
+	now = GetCurrentTimestamp();
+	TimestampDifference(startup_progress_phase_start_time, now, &seconds, &useconds);
+
+	*secs = seconds;
+	*usecs = useconds;
+	startup_progress_timer_expired = false;
+
+	return true;
+}