Fix Win32 problems with signals and sockets, by making the forkexec code

even uglier than it was already :-(.  Also, on Windows only, use temporary
shared memory segments instead of ordinary files to pass over critical
variable values from postmaster to child processes.  Magnus Hagander

src/backend/main/main.c

@@ -13,7 +13,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/main/main.c,v 1.92 2004/11/05 17:11:17 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/main/main.c,v 1.93 2004/11/17 00:14:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -118,9 +118,6 @@ main(int argc, char *argv[])
 						 argv[0], err);
 			exit(1);
 		}
-
-		/* Start our win32 signal implementation */
-		pgwin32_signal_initialize();
 	}
 #endif
 
@@ -281,6 +278,16 @@ main(int argc, char *argv[])
 		exit(SubPostmasterMain(argc, argv));
 #endif
 
+#ifdef WIN32
+	/*
+	 * Start our win32 signal implementation
+	 *
+	 * SubPostmasterMain() will do this for itself, but the remaining
+	 * modes need it here
+	 */
+	pgwin32_signal_initialize();
+#endif
+
 	/*
 	 * If the first argument is "-boot", then invoke bootstrap mode. (This
 	 * path is taken only for a standalone bootstrap process.)

src/backend/port/win32/signal.c

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/port/win32/signal.c,v 1.9 2004/11/09 13:01:25 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/port/win32/signal.c,v 1.10 2004/11/17 00:14:10 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -26,6 +26,7 @@ static pqsigfunc pg_signal_defaults[PG_SIGNAL_COUNT];
 static int	pg_signal_mask;
 
 DLLIMPORT HANDLE pgwin32_signal_event;
+HANDLE pgwin32_initial_signal_pipe = INVALID_HANDLE_VALUE;
 
 
 /* Signal handling thread function */
@@ -154,6 +155,28 @@ pqsignal(int signum, pqsigfunc handler)
 	return prevfunc;
 }
 
+/* Create the signal listener pipe for specified pid */
+HANDLE
+pgwin32_create_signal_listener(pid_t pid)
+{
+	char		pipename[128];
+	HANDLE		pipe;
+
+	wsprintf(pipename, "\\\\.\\pipe\\pgsignal_%d", (int) pid);
+
+	pipe = CreateNamedPipe(pipename, PIPE_ACCESS_DUPLEX,
+						   PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE | PIPE_WAIT,
+						   PIPE_UNLIMITED_INSTANCES, 16, 16, 1000, NULL);
+
+	if (pipe == INVALID_HANDLE_VALUE)
+		ereport(ERROR,
+				(errmsg("could not create signal listener pipe for pid %d: error code %d",
+						(int) pid, (int) GetLastError())));
+
+	return pipe;
+}
+
+
 /*
  * All functions below execute on the signal handler thread
  * and must be synchronized as such!
@@ -210,7 +233,7 @@ static DWORD WINAPI
 pg_signal_thread(LPVOID param)
 {
 	char		pipename[128];
-	HANDLE		pipe = INVALID_HANDLE_VALUE;
+	HANDLE      pipe = pgwin32_initial_signal_pipe;
 
 	wsprintf(pipename, "\\\\.\\pipe\\pgsignal_%d", GetCurrentProcessId());
 
@@ -219,15 +242,19 @@ pg_signal_thread(LPVOID param)
 		BOOL		fConnected;
 		HANDLE		hThread;
 
+		if (pipe == INVALID_HANDLE_VALUE)
+		{
 			pipe = CreateNamedPipe(pipename, PIPE_ACCESS_DUPLEX,
 								   PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE | PIPE_WAIT,
 								   PIPE_UNLIMITED_INSTANCES, 16, 16, 1000, NULL);
+
 			if (pipe == INVALID_HANDLE_VALUE)
 			{
 				write_stderr("could not create signal listener pipe: error code %d; retrying\n", (int) GetLastError());
 				SleepEx(500, FALSE);
 				continue;
 			}
+		}
 
 		fConnected = ConnectNamedPipe(pipe, NULL) ? TRUE : (GetLastError() == ERROR_PIPE_CONNECTED);
 		if (fConnected)
@@ -244,6 +271,9 @@ pg_signal_thread(LPVOID param)
 		else
 			/* Connection failed. Cleanup and try again */
 			CloseHandle(pipe);
+
+		/* Set up so we create a new pipe on next loop */
+		pipe = INVALID_HANDLE_VALUE;
 	}
 	return 0;
 }

src/backend/postmaster/pgstat.c

@@ -13,7 +13,7 @@
  *
  *	Copyright (c) 2001-2004, PostgreSQL Global Development Group
  *
- *	$PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.84 2004/10/28 01:38:41 neilc Exp $
+ *	$PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.85 2004/11/17 00:14:12 tgl Exp $
  * ----------
  */
 #include "postgres.h"
@@ -110,8 +110,9 @@ bool		pgstat_collect_blocklevel = false;
  * ----------
  */
 NON_EXEC_STATIC int pgStatSock = -1;
-static int	pgStatPipe[2];
+NON_EXEC_STATIC int pgStatPipe[2] = {-1,-1};
 static struct sockaddr_storage pgStatAddr;
+static pid_t pgStatCollectorPid = 0;
 
 static time_t last_pgstat_start_time;
 
@@ -492,10 +493,6 @@ pgstat_forkexec(STATS_PROCESS_TYPE procType)
 	/* postgres_exec_path is not passed by write_backend_variables */
 	av[ac++] = postgres_exec_path;
 
-	/* Pipe file ids (those not passed by write_backend_variables) */
-	snprintf(pgstatBuf[bufc++], 32, "%d", pgStatPipe[0]);
-	snprintf(pgstatBuf[bufc++], 32, "%d", pgStatPipe[1]);
-
 	/* Add to the arg list */
 	Assert(bufc <= lengthof(pgstatBuf));
 	for (i = 0; i < bufc; i++)
@@ -517,12 +514,10 @@ pgstat_forkexec(STATS_PROCESS_TYPE procType)
 static void
 pgstat_parseArgs(int argc, char *argv[])
 {
-	Assert(argc == 6);
+	Assert(argc == 4);
 
 	argc = 3;
 	StrNCpy(postgres_exec_path, argv[argc++], MAXPGPATH);
-	pgStatPipe[0] = atoi(argv[argc++]);
-	pgStatPipe[1] = atoi(argv[argc++]);
 }
 #endif   /* EXEC_BACKEND */
 
@@ -1385,12 +1380,13 @@ PgstatBufferMain(int argc, char *argv[])
 				(errcode_for_socket_access(),
 			 errmsg("could not create pipe for statistics buffer: %m")));
 
-#ifdef EXEC_BACKEND
 	/* child becomes collector process */
-	switch (pgstat_forkexec(STAT_PROC_COLLECTOR))
+#ifdef EXEC_BACKEND
+	pgStatCollectorPid = pgstat_forkexec(STAT_PROC_COLLECTOR);
 #else
-	switch (fork())
+	pgStatCollectorPid = fork();
 #endif
+	switch (pgStatCollectorPid)
 	{
 		case -1:
 			ereport(ERROR,
@@ -1445,7 +1441,12 @@ PgstatCollectorMain(int argc, char *argv[])
 	pqsignal(SIGHUP, SIG_IGN);
 	pqsignal(SIGINT, SIG_IGN);
 	pqsignal(SIGTERM, SIG_IGN);
+#ifndef WIN32
 	pqsignal(SIGQUIT, SIG_IGN);
+#else
+	/* kluge to allow buffer process to kill collector; FIXME */
+	pqsignal(SIGQUIT, pgstat_exit);
+#endif
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
 	pqsignal(SIGUSR1, SIG_IGN);
@@ -1943,6 +1944,16 @@ pgstat_exit(SIGNAL_ARGS)
 	 * be cleaner to allow any pending messages to be sent, but that
 	 * creates a tradeoff against speed of exit.
 	 */
+
+	/*
+	 * If running in bufferer, kill our collector as well. On some broken
+	 * win32 systems, it does not shut down automatically because of issues
+	 * with socket inheritance.  XXX so why not fix the socket inheritance...
+	 */
+#ifdef WIN32
+	if (pgStatCollectorPid > 0)
+		kill(pgStatCollectorPid, SIGQUIT);
+#endif
 	exit(0);
 }
 

src/include/port/win32.h

-/* $PostgreSQL: pgsql/src/include/port/win32.h,v 1.39 2004/10/06 17:47:53 momjian Exp $ */
+/* $PostgreSQL: pgsql/src/include/port/win32.h,v 1.40 2004/11/17 00:14:14 tgl Exp $ */
 
 /* undefine and redefine after #include */
 #undef mkdir
@@ -104,8 +104,11 @@ int			semop(int semId, struct sembuf * sops, int flag);
 
 
 /* In backend/port/win32/signal.c */
-void		pgwin32_signal_initialize(void);
 extern DLLIMPORT HANDLE pgwin32_signal_event;
+extern HANDLE pgwin32_initial_signal_pipe;
+
+void		pgwin32_signal_initialize(void);
+HANDLE		pgwin32_create_signal_listener(pid_t pid);
 void		pgwin32_dispatch_queued_signals(void);
 void		pg_queue_signal(int signum);