Fix assorted issues in pg_ctl's pgwin32_CommandLine().

Ensure that the invocation command for postgres or pg_ctl runservice
double-quotes the executable's pathname; failure to do this leads to
trouble when the path contains spaces.

Also, ensure that the path ends in ".exe" in both cases and uses
backslashes rather than slashes as directory separators.  The latter issue
is reported to confuse some third-party tools such as Symantec Backup Exec.

Also, rewrite the function to avoid buffer overrun issues by using a
PQExpBuffer instead of a fixed-size static buffer.  Combinations of
very long executable pathnames and very long data directory pathnames
could have caused trouble before, for example.

Back-patch to all active branches, since this code has been like this
for a long while.

Naoya Anzai and Tom Lane, reviewed by Rajeev Rastogi

src/bin/pg_ctl/pg_ctl.c

@@ -18,7 +18,9 @@
 #endif
 
 #include "postgres_fe.h"
+
 #include "libpq-fe.h"
+#include "pqexpbuffer.h"
 
 #include <fcntl.h>
 #include <locale.h>
@@ -1238,16 +1240,13 @@ pgwin32_IsInstalled(SC_HANDLE hSCM)
 static char *
 pgwin32_CommandLine(bool registration)
 {
-	static char cmdLine[MAXPGPATH];
+	PQExpBuffer cmdLine = createPQExpBuffer();
+	char		cmdPath[MAXPGPATH];
 	int			ret;
 
-#ifdef __CYGWIN__
-	char		buf[MAXPGPATH];
-#endif
-
 	if (registration)
 	{
-		ret = find_my_exec(argv0, cmdLine);
+		ret = find_my_exec(argv0, cmdPath);
 		if (ret != 0)
 		{
 			write_stderr(_("%s: could not find own program executable\n"), progname);
@@ -1257,7 +1256,7 @@ pgwin32_CommandLine(bool registration)
 	else
 	{
 		ret = find_other_exec(argv0, "postgres", PG_BACKEND_VERSIONSTR,
-							  cmdLine);
+							  cmdPath);
 		if (ret != 0)
 		{
 			write_stderr(_("%s: could not find postgres program executable\n"), progname);
@@ -1267,54 +1266,57 @@ pgwin32_CommandLine(bool registration)
 
 #ifdef __CYGWIN__
 	/* need to convert to windows path */
+	{
+		char		buf[MAXPGPATH];
+
 #if CYGWIN_VERSION_DLL_MAJOR >= 1007
-	cygwin_conv_path(CCP_POSIX_TO_WIN_A, cmdLine, buf, sizeof(buf));
+		cygwin_conv_path(CCP_POSIX_TO_WIN_A, cmdPath, buf, sizeof(buf));
 #else
-	cygwin_conv_to_full_win32_path(cmdLine, buf);
+		cygwin_conv_to_full_win32_path(cmdPath, buf);
 #endif
-	strcpy(cmdLine, buf);
+		strcpy(cmdPath, buf);
+	}
 #endif
 
+	/* if path does not end in .exe, append it */
+	if (strlen(cmdPath) < 4 ||
+		pg_strcasecmp(cmdPath + strlen(cmdPath) - 4, ".exe") != 0)
+		snprintf(cmdPath + strlen(cmdPath), sizeof(cmdPath) - strlen(cmdPath),
+				 ".exe");
+
+	/* use backslashes in path to avoid problems with some third-party tools */
+	make_native_path(cmdPath);
+
+	/* be sure to double-quote the executable's name in the command */
+	appendPQExpBuffer(cmdLine, "\"%s\"", cmdPath);
+
+	/* append assorted switches to the command line, as needed */
+
 	if (registration)
-	{
-		if (pg_strcasecmp(cmdLine + strlen(cmdLine) - 4, ".exe") != 0)
-		{
-			/* If commandline does not end in .exe, append it */
-			strcat(cmdLine, ".exe");
-		}
-		strcat(cmdLine, " runservice -N \"");
-		strcat(cmdLine, register_servicename);
-		strcat(cmdLine, "\"");
-	}
+		appendPQExpBuffer(cmdLine, " runservice -N \"%s\"",
+						  register_servicename);
 
 	if (pg_config)
-	{
-		strcat(cmdLine, " -D \"");
-		strcat(cmdLine, pg_config);
-		strcat(cmdLine, "\"");
-	}
+		appendPQExpBuffer(cmdLine, " -D \"%s\"", pg_config);
 
 	if (registration && do_wait)
-		strcat(cmdLine, " -w");
+		appendPQExpBuffer(cmdLine, " -w");
 
 	if (registration && wait_seconds != DEFAULT_WAIT)
-		/* concatenate */
-		sprintf(cmdLine + strlen(cmdLine), " -t %d", wait_seconds);
+		appendPQExpBuffer(cmdLine, " -t %d", wait_seconds);
 
 	if (registration && silent_mode)
-		strcat(cmdLine, " -s");
+		appendPQExpBuffer(cmdLine, " -s");
 
 	if (post_opts)
 	{
-		strcat(cmdLine, " ");
-		if (registration)
-			strcat(cmdLine, " -o \"");
-		strcat(cmdLine, post_opts);
 		if (registration)
-			strcat(cmdLine, "\"");
+			appendPQExpBuffer(cmdLine, " -o \"%s\"", post_opts);
+		else
+			appendPQExpBuffer(cmdLine, " %s", post_opts);
 	}
 
-	return cmdLine;
+	return cmdLine->data;
 }
 
 static void
@@ -1745,7 +1747,7 @@ CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo, bool as_ser
 	 */
 	return r;
 }
-#endif
+#endif   /* defined(WIN32) || defined(__CYGWIN__) */
 
 static void
 do_advice(void)