path: root/src/backend/postmaster/launch_backend.c

/*-------------------------------------------------------------------------
 *
 * launch_backend.c
 *	  Functions for launching backends and other postmaster child
 *	  processes.
 *
 * On Unix systems, a new child process is launched with fork().  It inherits
 * all the global variables and data structures that had been initialized in
 * the postmaster.  After forking, the child process closes the file
 * descriptors that are not needed in the child process, and sets up the
 * mechanism to detect death of the parent postmaster process, etc.  After
 * that, it calls the right Main function depending on the kind of child
 * process.
 *
 * In EXEC_BACKEND mode, which is used on Windows but can be enabled on other
 * platforms for testing, the child process is launched by fork() + exec() (or
 * CreateProcess() on Windows).  It does not inherit the state from the
 * postmaster, so it needs to re-attach to the shared memory, re-initialize
 * global variables, reload the config file etc. to get the process to the
 * same state as after fork() on a Unix system.
 *
 *
 * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *	  src/backend/postmaster/launch_backend.c
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include <unistd.h>

#include "access/xlog.h"
#include "common/file_utils.h"
#include "libpq/libpq-be.h"
#include "libpq/pqsignal.h"
#include "miscadmin.h"
#include "nodes/queryjumble.h"
#include "port.h"
#include "postmaster/autovacuum.h"
#include "postmaster/auxprocess.h"
#include "postmaster/bgworker_internals.h"
#include "postmaster/bgwriter.h"
#include "postmaster/fork_process.h"
#include "postmaster/pgarch.h"
#include "postmaster/postmaster.h"
#include "postmaster/startup.h"
#include "postmaster/syslogger.h"
#include "postmaster/walwriter.h"
#include "replication/walreceiver.h"
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/pg_shmem.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/datetime.h"
#include "utils/guc.h"
#include "utils/memutils.h"
#include "utils/timestamp.h"

#ifdef EXEC_BACKEND
#include "nodes/queryjumble.h"
#include "storage/pg_shmem.h"
#include "storage/spin.h"
#endif


#ifdef EXEC_BACKEND

/* Type for a socket that can be inherited to a client process */
#ifdef WIN32
typedef struct
{
	SOCKET		origsocket;		/* Original socket value, or PGINVALID_SOCKET
								 * if not a socket */
	WSAPROTOCOL_INFO wsainfo;
} InheritableSocket;
#else
typedef int InheritableSocket;
#endif

/*
 * Structure contains all variables passed to exec:ed backends
 */
typedef struct
{
	bool		has_client_sock;
	ClientSocket client_sock;
	InheritableSocket inh_sock;

	bool		has_bgworker;
	BackgroundWorker bgworker;

	char		DataDir[MAXPGPATH];
	int32		MyCancelKey;
	int			MyPMChildSlot;
#ifndef WIN32
	unsigned long UsedShmemSegID;
#else
	void	   *ShmemProtectiveRegion;
	HANDLE		UsedShmemSegID;
#endif
	void	   *UsedShmemSegAddr;
	slock_t    *ShmemLock;
	struct bkend *ShmemBackendArray;
#ifndef HAVE_SPINLOCKS
	PGSemaphore *SpinlockSemaArray;
#endif
	int			NamedLWLockTrancheRequests;
	NamedLWLockTranche *NamedLWLockTrancheArray;
	LWLockPadded *MainLWLockArray;
	slock_t    *ProcStructLock;
	PROC_HDR   *ProcGlobal;
	PGPROC	   *AuxiliaryProcs;
	PGPROC	   *PreparedXactProcs;
	PMSignalData *PMSignalState;
	pid_t		PostmasterPid;
	TimestampTz PgStartTime;
	TimestampTz PgReloadTime;
	pg_time_t	first_syslogger_file_time;
	bool		redirection_done;
	bool		IsBinaryUpgrade;
	bool		query_id_enabled;
	int			max_safe_fds;
	int			MaxBackends;
#ifdef WIN32
	HANDLE		PostmasterHandle;
	HANDLE		initial_signal_pipe;
	HANDLE		syslogPipe[2];
#else
	int			postmaster_alive_fds[2];
	int			syslogPipe[2];
#endif
	char		my_exec_path[MAXPGPATH];
	char		pkglib_path[MAXPGPATH];
} BackendParameters;

#define SizeOfBackendParameters(startup_data_len) (offsetof(BackendParameters, startup_data) + startup_data_len)

void		read_backend_variables(char *id, ClientSocket **client_sock, BackgroundWorker **worker);
static void restore_backend_variables(BackendParameters *param, ClientSocket **client_sock, BackgroundWorker **worker);

#ifndef WIN32
static bool save_backend_variables(BackendParameters *param, ClientSocket *client_sock, BackgroundWorker *worker);
#else
static bool save_backend_variables(BackendParameters *param, ClientSocket *client_sock, BackgroundWorker *worker,
								   HANDLE childProcess, pid_t childPid);
#endif

pid_t		internal_forkexec(int argc, char *argv[], ClientSocket *client_sock, BackgroundWorker *worker);

#ifndef WIN32

/*
 * internal_forkexec non-win32 implementation
 *
 * - writes out backend variables to the parameter file
 * - fork():s, and then exec():s the child process
 */
pid_t
internal_forkexec(int argc, char *argv[], ClientSocket *client_sock, BackgroundWorker *worker)
{
	static unsigned long tmpBackendFileNum = 0;
	pid_t		pid;
	char		tmpfilename[MAXPGPATH];
	BackendParameters param;
	FILE	   *fp;

	/*
	 * Make sure padding bytes are initialized, to prevent Valgrind from
	 * complaining about writing uninitialized bytes to the file.  This isn't
	 * performance critical, and the win32 implementation initializes the
	 * padding bytes to zeros, so do it even when not using Valgrind.
	 */
	memset(&param, 0, sizeof(BackendParameters));

	if (!save_backend_variables(&param, client_sock, worker))
		return -1;				/* log made by save_backend_variables */

	/* Calculate name for temp file */
	snprintf(tmpfilename, MAXPGPATH, "%s/%s.backend_var.%d.%lu",
			 PG_TEMP_FILES_DIR, PG_TEMP_FILE_PREFIX,
			 MyProcPid, ++tmpBackendFileNum);

	/* Open file */
	fp = AllocateFile(tmpfilename, PG_BINARY_W);
	if (!fp)
	{
		/*
		 * As in OpenTemporaryFileInTablespace, try to make the temp-file
		 * directory, ignoring errors.
		 */
		(void) MakePGDirectory(PG_TEMP_FILES_DIR);

		fp = AllocateFile(tmpfilename, PG_BINARY_W);
		if (!fp)
		{
			ereport(LOG,
					(errcode_for_file_access(),
					 errmsg("could not create file \"%s\": %m",
							tmpfilename)));
			return -1;
		}
	}

	if (fwrite(&param, sizeof(param), 1, fp) != 1)
	{
		ereport(LOG,
				(errcode_for_file_access(),
				 errmsg("could not write to file \"%s\": %m", tmpfilename)));
		FreeFile(fp);
		return -1;
	}

	/* Release file */
	if (FreeFile(fp))
	{
		ereport(LOG,
				(errcode_for_file_access(),
				 errmsg("could not write to file \"%s\": %m", tmpfilename)));
		return -1;
	}

	/* Make sure caller set up argv properly */
	Assert(argc >= 3);
	Assert(argv[argc] == NULL);
	Assert(strncmp(argv[1], "--fork", 6) == 0);
	Assert(argv[2] == NULL);

	/* Insert temp file name after --fork argument */
	argv[2] = tmpfilename;

	/* Fire off execv in child */
	if ((pid = fork_process()) == 0)
	{
		if (execv(postgres_exec_path, argv) < 0)
		{
			ereport(LOG,
					(errmsg("could not execute server process \"%s\": %m",
							postgres_exec_path)));
			/* We're already in the child process here, can't return */
			exit(1);
		}
	}

	return pid;					/* Parent returns pid, or -1 on fork failure */
}
#else							/* WIN32 */

/*
 * internal_forkexec win32 implementation
 *
 * - starts backend using CreateProcess(), in suspended state
 * - writes out backend variables to the parameter file
 *	- during this, duplicates handles and sockets required for
 *	  inheritance into the new process
 * - resumes execution of the new process once the backend parameter
 *	 file is complete.
 */
pid_t
internal_forkexec(int argc, char *argv[], ClientSocket *client_sock, BackgroundWorker *worker)
{
	int			retry_count = 0;
	STARTUPINFO si;
	PROCESS_INFORMATION pi;
	int			i;
	int			j;
	char		cmdLine[MAXPGPATH * 2];
	HANDLE		paramHandle;
	BackendParameters *param;
	SECURITY_ATTRIBUTES sa;
	char		paramHandleStr[32];

	/* Make sure caller set up argv properly */
	Assert(argc >= 3);
	Assert(argv[argc] == NULL);
	Assert(strncmp(argv[1], "--fork", 6) == 0);
	Assert(argv[2] == NULL);

	/* Resume here if we need to retry */
retry:

	/* Set up shared memory for parameter passing */
	ZeroMemory(&sa, sizeof(sa));
	sa.nLength = sizeof(sa);
	sa.bInheritHandle = TRUE;
	paramHandle = CreateFileMapping(INVALID_HANDLE_VALUE,
									&sa,
									PAGE_READWRITE,
									0,
									sizeof(BackendParameters),
									NULL);
	if (paramHandle == INVALID_HANDLE_VALUE)
	{
		ereport(LOG,
				(errmsg("could not create backend parameter file mapping: error code %lu",
						GetLastError())));
		return -1;
	}

	param = MapViewOfFile(paramHandle, FILE_MAP_WRITE, 0, 0, sizeof(BackendParameters));
	if (!param)
	{
		ereport(LOG,
				(errmsg("could not map backend parameter memory: error code %lu",
						GetLastError())));
		CloseHandle(paramHandle);
		return -1;
	}

	/* Insert temp file name after --fork argument */
#ifdef _WIN64
	sprintf(paramHandleStr, "%llu", (LONG_PTR) paramHandle);
#else
	sprintf(paramHandleStr, "%lu", (DWORD) paramHandle);
#endif
	argv[2] = paramHandleStr;

	/* Format the cmd line */
	cmdLine[sizeof(cmdLine) - 1] = '\0';
	cmdLine[sizeof(cmdLine) - 2] = '\0';
	snprintf(cmdLine, sizeof(cmdLine) - 1, "\"%s\"", postgres_exec_path);
	i = 0;
	while (argv[++i] != NULL)
	{
		j = strlen(cmdLine);
		snprintf(cmdLine + j, sizeof(cmdLine) - 1 - j, " \"%s\"", argv[i]);
	}
	if (cmdLine[sizeof(cmdLine) - 2] != '\0')
	{
		ereport(LOG,
				(errmsg("subprocess command line too long")));
		UnmapViewOfFile(param);
		CloseHandle(paramHandle);
		return -1;
	}

	memset(&pi, 0, sizeof(pi));
	memset(&si, 0, sizeof(si));
	si.cb = sizeof(si);

	/*
	 * Create the subprocess in a suspended state. This will be resumed later,
	 * once we have written out the parameter file.
	 */
	if (!CreateProcess(NULL, cmdLine, NULL, NULL, TRUE, CREATE_SUSPENDED,
					   NULL, NULL, &si, &pi))
	{
		ereport(LOG,
				(errmsg("CreateProcess() call failed: %m (error code %lu)",
						GetLastError())));
		UnmapViewOfFile(param);
		CloseHandle(paramHandle);
		return -1;
	}

	if (!save_backend_variables(param, client_sock, worker, pi.hProcess, pi.dwProcessId))
	{
		/*
		 * log made by save_backend_variables, but we have to clean up the
		 * mess with the half-started process
		 */
		if (!TerminateProcess(pi.hProcess, 255))
			ereport(LOG,
					(errmsg_internal("could not terminate unstarted process: error code %lu",
									 GetLastError())));
		CloseHandle(pi.hProcess);
		CloseHandle(pi.hThread);
		UnmapViewOfFile(param);
		CloseHandle(paramHandle);
		return -1;				/* log made by save_backend_variables */
	}

	/* Drop the parameter shared memory that is now inherited to the backend */
	if (!UnmapViewOfFile(param))
		ereport(LOG,
				(errmsg("could not unmap view of backend parameter file: error code %lu",
						GetLastError())));
	if (!CloseHandle(paramHandle))
		ereport(LOG,
				(errmsg("could not close handle to backend parameter file: error code %lu",
						GetLastError())));

	/*
	 * Reserve the memory region used by our main shared memory segment before
	 * we resume the child process.  Normally this should succeed, but if ASLR
	 * is active then it might sometimes fail due to the stack or heap having
	 * gotten mapped into that range.  In that case, just terminate the
	 * process and retry.
	 */
	if (!pgwin32_ReserveSharedMemoryRegion(pi.hProcess))
	{
		/* pgwin32_ReserveSharedMemoryRegion already made a log entry */
		if (!TerminateProcess(pi.hProcess, 255))
			ereport(LOG,
					(errmsg_internal("could not terminate process that failed to reserve memory: error code %lu",
									 GetLastError())));
		CloseHandle(pi.hProcess);
		CloseHandle(pi.hThread);
		if (++retry_count < 100)
			goto retry;
		ereport(LOG,
				(errmsg("giving up after too many tries to reserve shared memory"),
				 errhint("This might be caused by ASLR or antivirus software.")));
		return -1;
	}

	/*
	 * Now that the backend variables are written out, we start the child
	 * thread so it can start initializing while we set up the rest of the
	 * parent state.
	 */
	if (ResumeThread(pi.hThread) == -1)
	{
		if (!TerminateProcess(pi.hProcess, 255))
		{
			ereport(LOG,
					(errmsg_internal("could not terminate unstartable process: error code %lu",
									 GetLastError())));
			CloseHandle(pi.hProcess);
			CloseHandle(pi.hThread);
			return -1;
		}
		CloseHandle(pi.hProcess);
		CloseHandle(pi.hThread);
		ereport(LOG,
				(errmsg_internal("could not resume thread of unstarted process: error code %lu",
								 GetLastError())));
		return -1;
	}

	/* Set up notification when the child process dies */
	pgwin32_register_deadchild_callback(pi.hProcess, pi.dwProcessId);

	/* Don't close pi.hProcess, it's owned by the deadchild callback now */

	CloseHandle(pi.hThread);

	return pi.dwProcessId;
}
#endif							/* WIN32 */

/*
 * The following need to be available to the save/restore_backend_variables
 * functions.  They are marked NON_EXEC_STATIC in their home modules.
 */
extern slock_t *ShmemLock;
extern slock_t *ProcStructLock;
extern PGPROC *AuxiliaryProcs;
extern PMSignalData *PMSignalState;
extern pg_time_t first_syslogger_file_time;
extern struct bkend *ShmemBackendArray;
extern bool redirection_done;

#ifndef WIN32
#define write_inheritable_socket(dest, src, childpid) ((*(dest) = (src)), true)
#define read_inheritable_socket(dest, src) (*(dest) = *(src))
#else
static bool write_duplicated_handle(HANDLE *dest, HANDLE src, HANDLE child);
static bool write_inheritable_socket(InheritableSocket *dest, SOCKET src,
									 pid_t childPid);
static void read_inheritable_socket(SOCKET *dest, InheritableSocket *src);
#endif


/* Save critical backend variables into the BackendParameters struct */
#ifndef WIN32
static bool
save_backend_variables(BackendParameters *param, ClientSocket *client_sock, BackgroundWorker *worker)
#else
static bool
save_backend_variables(BackendParameters *param, ClientSocket *client_sock, BackgroundWorker *worker,
					   HANDLE childProcess, pid_t childPid)
#endif
{
	if (client_sock)
	{
		memcpy(&param->client_sock, client_sock, sizeof(ClientSocket));
		if (!write_inheritable_socket(&param->inh_sock, client_sock->sock, childPid))
			return false;
		param->has_client_sock = true;
	}
	else
	{
		memset(&param->client_sock, 0, sizeof(ClientSocket));
		param->has_client_sock = false;
	}

	if (worker)
	{
		memcpy(&param->bgworker, worker, sizeof(BackgroundWorker));
		param->has_bgworker = true;
	}
	else
	{
		memset(&param->bgworker, 0, sizeof(BackgroundWorker));
		param->has_bgworker = false;
	}

	strlcpy(param->DataDir, DataDir, MAXPGPATH);

	param->MyCancelKey = MyCancelKey;
	param->MyPMChildSlot = MyPMChildSlot;

#ifdef WIN32
	param->ShmemProtectiveRegion = ShmemProtectiveRegion;
#endif
	param->UsedShmemSegID = UsedShmemSegID;
	param->UsedShmemSegAddr = UsedShmemSegAddr;

	param->ShmemLock = ShmemLock;
	param->ShmemBackendArray = ShmemBackendArray;

#ifndef HAVE_SPINLOCKS
	param->SpinlockSemaArray = SpinlockSemaArray;
#endif
	param->NamedLWLockTrancheRequests = NamedLWLockTrancheRequests;
	param->NamedLWLockTrancheArray = NamedLWLockTrancheArray;
	param->MainLWLockArray = MainLWLockArray;
	param->ProcStructLock = ProcStructLock;
	param->ProcGlobal = ProcGlobal;
	param->AuxiliaryProcs = AuxiliaryProcs;
	param->PreparedXactProcs = PreparedXactProcs;
	param->PMSignalState = PMSignalState;

	param->PostmasterPid = PostmasterPid;
	param->PgStartTime = PgStartTime;
	param->PgReloadTime = PgReloadTime;
	param->first_syslogger_file_time = first_syslogger_file_time;

	param->redirection_done = redirection_done;
	param->IsBinaryUpgrade = IsBinaryUpgrade;
	param->query_id_enabled = query_id_enabled;
	param->max_safe_fds = max_safe_fds;

	param->MaxBackends = MaxBackends;

#ifdef WIN32
	param->PostmasterHandle = PostmasterHandle;
	if (!write_duplicated_handle(&param->initial_signal_pipe,
								 pgwin32_create_signal_listener(childPid),
								 childProcess))
		return false;
#else
	memcpy(&param->postmaster_alive_fds, &postmaster_alive_fds,
		   sizeof(postmaster_alive_fds));
#endif

	memcpy(&param->syslogPipe, &syslogPipe, sizeof(syslogPipe));

	strlcpy(param->my_exec_path, my_exec_path, MAXPGPATH);

	strlcpy(param->pkglib_path, pkglib_path, MAXPGPATH);

	return true;
}

#ifdef WIN32
/*
 * Duplicate a handle for usage in a child process, and write the child
 * process instance of the handle to the parameter file.
 */
static bool
write_duplicated_handle(HANDLE *dest, HANDLE src, HANDLE childProcess)
{
	HANDLE		hChild = INVALID_HANDLE_VALUE;

	if (!DuplicateHandle(GetCurrentProcess(),
						 src,
						 childProcess,
						 &hChild,
						 0,
						 TRUE,
						 DUPLICATE_CLOSE_SOURCE | DUPLICATE_SAME_ACCESS))
	{
		ereport(LOG,
				(errmsg_internal("could not duplicate handle to be written to backend parameter file: error code %lu",
								 GetLastError())));
		return false;
	}

	*dest = hChild;
	return true;
}

/*
 * Duplicate a socket for usage in a child process, and write the resulting
 * structure to the parameter file.
 * This is required because a number of LSPs (Layered Service Providers) very
 * common on Windows (antivirus, firewalls, download managers etc) break
 * straight socket inheritance.
 */
static bool
write_inheritable_socket(InheritableSocket *dest, SOCKET src, pid_t childpid)
{
	dest->origsocket = src;
	if (src != 0 && src != PGINVALID_SOCKET)
	{
		/* Actual socket */
		if (WSADuplicateSocket(src, childpid, &dest->wsainfo) != 0)
		{
			ereport(LOG,
					(errmsg("could not duplicate socket %d for use in backend: error code %d",
							(int) src, WSAGetLastError())));
			return false;
		}
	}
	return true;
}

/*
 * Read a duplicate socket structure back, and get the socket descriptor.
 */
static void
read_inheritable_socket(SOCKET *dest, InheritableSocket *src)
{
	SOCKET		s;

	if (src->origsocket == PGINVALID_SOCKET || src->origsocket == 0)
	{
		/* Not a real socket! */
		*dest = src->origsocket;
	}
	else
	{
		/* Actual socket, so create from structure */
		s = WSASocket(FROM_PROTOCOL_INFO,
					  FROM_PROTOCOL_INFO,
					  FROM_PROTOCOL_INFO,
					  &src->wsainfo,
					  0,
					  0);
		if (s == INVALID_SOCKET)
		{
			write_stderr("could not create inherited socket: error code %d\n",
						 WSAGetLastError());
			exit(1);
		}
		*dest = s;

		/*
		 * To make sure we don't get two references to the same socket, close
		 * the original one. (This would happen when inheritance actually
		 * works..
		 */
		closesocket(src->origsocket);
	}
}
#endif

void
read_backend_variables(char *id, ClientSocket **client_sock, BackgroundWorker **worker)
{
	BackendParameters param;

#ifndef WIN32
	/* Non-win32 implementation reads from file */
	FILE	   *fp;

	/* Open file */
	fp = AllocateFile(id, PG_BINARY_R);
	if (!fp)
	{
		write_stderr("could not open backend variables file \"%s\": %m\n", id);
		exit(1);
	}

	if (fread(&param, sizeof(param), 1, fp) != 1)
	{
		write_stderr("could not read from backend variables file \"%s\": %m\n", id);
		exit(1);
	}

	/* Release file */
	FreeFile(fp);
	if (unlink(id) != 0)
	{
		write_stderr("could not remove file \"%s\": %m\n", id);
		exit(1);
	}
#else
	/* Win32 version uses mapped file */
	HANDLE		paramHandle;
	BackendParameters *paramp;

#ifdef _WIN64
	paramHandle = (HANDLE) _atoi64(id);
#else
	paramHandle = (HANDLE) atol(id);
#endif
	paramp = MapViewOfFile(paramHandle, FILE_MAP_READ, 0, 0, 0);
	if (!paramp)
	{
		write_stderr("could not map view of backend variables: error code %lu\n",
					 GetLastError());
		exit(1);
	}

	memcpy(&param, paramp, sizeof(BackendParameters));

	if (!UnmapViewOfFile(paramp))
	{
		write_stderr("could not unmap view of backend variables: error code %lu\n",
					 GetLastError());
		exit(1);
	}

	if (!CloseHandle(paramHandle))
	{
		write_stderr("could not close handle to backend parameter variables: error code %lu\n",
					 GetLastError());
		exit(1);
	}
#endif

	restore_backend_variables(&param, client_sock, worker);
}

/* Restore critical backend variables from the BackendParameters struct */
static void
restore_backend_variables(BackendParameters *param, ClientSocket **client_sock, BackgroundWorker **worker)
{
	if (param->has_client_sock)
	{
		*client_sock = (ClientSocket *) MemoryContextAlloc(TopMemoryContext, sizeof(ClientSocket));
		memcpy(*client_sock, &param->client_sock, sizeof(ClientSocket));
		read_inheritable_socket(&(*client_sock)->sock, &param->inh_sock);
	}
	else
		*client_sock = NULL;

	if (param->has_bgworker)
	{
		*worker = (BackgroundWorker *)
			MemoryContextAlloc(TopMemoryContext, sizeof(BackgroundWorker));
		memcpy(*worker, &param->bgworker, sizeof(BackgroundWorker));
	}
	else
		*worker = NULL;

	SetDataDir(param->DataDir);

	MyCancelKey = param->MyCancelKey;
	MyPMChildSlot = param->MyPMChildSlot;

#ifdef WIN32
	ShmemProtectiveRegion = param->ShmemProtectiveRegion;
#endif
	UsedShmemSegID = param->UsedShmemSegID;
	UsedShmemSegAddr = param->UsedShmemSegAddr;

	ShmemLock = param->ShmemLock;
	ShmemBackendArray = param->ShmemBackendArray;

#ifndef HAVE_SPINLOCKS
	SpinlockSemaArray = param->SpinlockSemaArray;
#endif
	NamedLWLockTrancheRequests = param->NamedLWLockTrancheRequests;
	NamedLWLockTrancheArray = param->NamedLWLockTrancheArray;
	MainLWLockArray = param->MainLWLockArray;
	ProcStructLock = param->ProcStructLock;
	ProcGlobal = param->ProcGlobal;
	AuxiliaryProcs = param->AuxiliaryProcs;
	PreparedXactProcs = param->PreparedXactProcs;
	PMSignalState = param->PMSignalState;

	PostmasterPid = param->PostmasterPid;
	PgStartTime = param->PgStartTime;
	PgReloadTime = param->PgReloadTime;
	first_syslogger_file_time = param->first_syslogger_file_time;

	redirection_done = param->redirection_done;
	IsBinaryUpgrade = param->IsBinaryUpgrade;
	query_id_enabled = param->query_id_enabled;
	max_safe_fds = param->max_safe_fds;

	MaxBackends = param->MaxBackends;

#ifdef WIN32
	PostmasterHandle = param->PostmasterHandle;
	pgwin32_initial_signal_pipe = param->initial_signal_pipe;
#else
	memcpy(&postmaster_alive_fds, &param->postmaster_alive_fds,
		   sizeof(postmaster_alive_fds));
#endif

	memcpy(&syslogPipe, &param->syslogPipe, sizeof(syslogPipe));

	strlcpy(my_exec_path, param->my_exec_path, MAXPGPATH);

	strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);

	/*
	 * We need to restore fd.c's counts of externally-opened FDs; to avoid
	 * confusion, be sure to do this after restoring max_safe_fds.  (Note:
	 * BackendInitialize will handle this for (*client_sock)->sock.)
	 */
#ifndef WIN32
	if (postmaster_alive_fds[0] >= 0)
		ReserveExternalFD();
	if (postmaster_alive_fds[1] >= 0)
		ReserveExternalFD();
#endif
}

#endif							/* EXEC_BACKEND */