1 files changed, 73 insertions, 13 deletions

diff --git a/src/backend/main/main.c b/src/backend/main/main.c
index aea93a02298..3acb46bd464 100644
--- a/src/backend/main/main.c
+++ b/src/backend/main/main.c
@@ -43,6 +43,19 @@
 const char *progname;
 static bool reached_main = false;
 
+/* names of special must-be-first options for dispatching to subprograms */
+static const char *const DispatchOptionNames[] =
+{
+	[DISPATCH_CHECK] = "check",
+	[DISPATCH_BOOT] = "boot",
+	[DISPATCH_FORKCHILD] = "forkchild",
+	[DISPATCH_DESCRIBE_CONFIG] = "describe-config",
+	[DISPATCH_SINGLE] = "single",
+	/* DISPATCH_POSTMASTER has no name */
+};
+
+StaticAssertDecl(lengthof(DispatchOptionNames) == DISPATCH_POSTMASTER,
+				 "array length mismatch");
 
 static void startup_hacks(const char *progname);
 static void init_locale(const char *categoryname, int category, const char *locale);
@@ -57,6 +70,7 @@ int
 main(int argc, char *argv[])
 {
 	bool		do_check_root = true;
+	DispatchOption dispatch_option = DISPATCH_POSTMASTER;
 
 	reached_main = true;
 
@@ -179,26 +193,72 @@ main(int argc, char *argv[])
 	 * Dispatch to one of various subprograms depending on first argument.
 	 */
 
-	if (argc > 1 && strcmp(argv[1], "--check") == 0)
-		BootstrapModeMain(argc, argv, true);
-	else if (argc > 1 && strcmp(argv[1], "--boot") == 0)
-		BootstrapModeMain(argc, argv, false);
+	if (argc > 1 && argv[1][0] == '-' && argv[1][1] == '-')
+		dispatch_option = parse_dispatch_option(&argv[1][2]);
+
+	switch (dispatch_option)
+	{
+		case DISPATCH_CHECK:
+			BootstrapModeMain(argc, argv, true);
+			break;
+		case DISPATCH_BOOT:
+			BootstrapModeMain(argc, argv, false);
+			break;
+		case DISPATCH_FORKCHILD:
 #ifdef EXEC_BACKEND
-	else if (argc > 1 && strncmp(argv[1], "--forkchild", 11) == 0)
-		SubPostmasterMain(argc, argv);
+			SubPostmasterMain(argc, argv);
+#else
+			Assert(false);		/* should never happen */
 #endif
-	else if (argc > 1 && strcmp(argv[1], "--describe-config") == 0)
-		GucInfoMain();
-	else if (argc > 1 && strcmp(argv[1], "--single") == 0)
-		PostgresSingleUserMain(argc, argv,
-							   strdup(get_user_name_or_exit(progname)));
-	else
-		PostmasterMain(argc, argv);
+			break;
+		case DISPATCH_DESCRIBE_CONFIG:
+			GucInfoMain();
+			break;
+		case DISPATCH_SINGLE:
+			PostgresSingleUserMain(argc, argv,
+								   strdup(get_user_name_or_exit(progname)));
+			break;
+		case DISPATCH_POSTMASTER:
+			PostmasterMain(argc, argv);
+			break;
+	}
+
 	/* the functions above should not return */
 	abort();
 }
 
+/*
+ * Returns the matching DispatchOption value for the given option name.  If no
+ * match is found, DISPATCH_POSTMASTER is returned.
+ */
+DispatchOption
+parse_dispatch_option(const char *name)
+{
+	for (int i = 0; i < lengthof(DispatchOptionNames); i++)
+	{
+		/*
+		 * Unlike the other dispatch options, "forkchild" takes an argument,
+		 * so we just look for the prefix for that one.  For non-EXEC_BACKEND
+		 * builds, we never want to return DISPATCH_FORKCHILD, so skip over it
+		 * in that case.
+		 */
+		if (i == DISPATCH_FORKCHILD)
+		{
+#ifdef EXEC_BACKEND
+			if (strncmp(DispatchOptionNames[DISPATCH_FORKCHILD], name,
+						strlen(DispatchOptionNames[DISPATCH_FORKCHILD])) == 0)
+				return DISPATCH_FORKCHILD;
+#endif
+			continue;
+		}
+
+		if (strcmp(DispatchOptionNames[i], name) == 0)
+			return (DispatchOption) i;
+	}
 
+	/* no match means this is a postmaster */
+	return DISPATCH_POSTMASTER;
+}
 
 /*
  * Place platform-specific startup hacks here.  This is the right