Simplify, drop --enable-fallback-shell from configure script

Recommend using `notty` option in tty stanza instead.  See the updated
docs for details.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

configure.ac

@@ -53,10 +53,6 @@ AC_ARG_ENABLE(emergency_shell,
 	                Use only for debugging very early boot problems with Finit]),,[
 	enable_emergency_shell=no])
 
-AC_ARG_ENABLE(fallback_shell,
-        AS_HELP_STRING([--enable-fallback-shell], [Start a shell if no TTYs can start]),,[
-	enable_fallback_shell=no])
-
 AC_ARG_ENABLE(auto_reload,
         AS_HELP_STRING([--enable-auto-reload], [Automatic reload on any .conf change]),,[
 	enable_auto_reload=no])
@@ -130,13 +126,10 @@ AC_ARG_WITH(random-seed,
 
 ### Enable features ###########################################################################
 
-# Create config.h from selected features and fallback defautls
+# Create config.h from selected features and fallback defaults
 AS_IF([test "x$enable_emergency_shell" = "xyes"], [
         AC_DEFINE(EMERGENCY_SHELL,  1, [Fork off init and let PID 1 wait and start /bin/sh if init crashes.])])
 
-AS_IF([test "x$enable_fallback_shell" = "xyes"], [
-        AC_DEFINE(FALLBACK_SHELL,  1, [Start /bin/sh on console if no TTYs.])])
-
 AS_IF([test "x$enable_auto_reload" = "xyes"], [
         AC_DEFINE(AUTO_RELOAD, 1, [Finit automatically does `initctl reload` on any .conf change])])
 

doc/bootstrap.md

@@ -34,7 +34,7 @@ Bootstrap
 24. Call 4th level hooks, `HOOK_SVC_UP`
 25. Call `/etc/rc.local`, if it exists and is an executable shell script
 26. Call 5th level (last) hooks, `HOOK_SYSTEM_UP`
-27. Start all configured TTYs, or a fallback shell on `/dev/console`
+27. Start all configured TTYs
 
 In (19) and (22) tasks and services defined in `/etc/finit.conf` and
 `/etc/sysctl.d/*.conf` are started.  Remember, all `service` and `task`

doc/build.md

@@ -153,19 +153,22 @@ kernel messages and add `debug` to enable Finit debug messages.
 append="init=/sbin/finit debug"
 ```
 
-To debug startup issues, in particular issues with getty/login, try
-`configure --enable-fallback-shell`.  When no TTYs are detected, and
-Finit is configured with this option, Finit will try to start a bare
-`/bin/sh` on the boot console.  Remember, this is only for debugging
-and would leave your production system potentially wide open.
+To debug startup issues, in particular issues with getty/login, add
+the following to your Finit .conf file:
+
+    tty [12345789] notty noclear
+
+The `notty` option ensures reusing the stdin/stdout set up by the
+kernel.  Remember, this is only for debugging and would leave your
+production system potentially wide open.
 
 There is also a rescue shell available, in case Finit crashes and the
 kernel usually reboots: `configure --enable-emergency-shell`.  However,
 the behavior of Finit is severely limited when this is enabled, so use
 it only for debugging start up issues when Finit crashes.
 
-**NOTE:** Neither of these two configure options should be enabled on
-  production systems since they can potentially give a user root access.
+**NOTE:** Neither of these options should be enabled on production
+         systems since they can potentially give a user root access.
 
 
 [1]:       ftp://troglobit.com/finit/finit-3.0.tar.xz

doc/config.md

@@ -522,12 +522,14 @@ can be omitted to keep the kernel default.
 
     tty [12345] @console noclear vt220
 
-On really bare bones systems Finit offers a fallback shell, which
-should not be enabled on production systems since.  This because it
-may give a user root access without having to log in.  However, for
-bringup and system debugging it can come in handy:
+On really bare bones systems Finit can give you a shell prompt as
+soon as bootstrap is done, without opening any device node:
 
-    configure --enable-fallback-shell
+    tty [12345789] notty noclear
+
+This should of course not be enabled on production systems.  Because it
+may give a user root access without having to log in.  However, for
+board bringup and system debugging it can come in handy.
 
 One can also use the `service` stanza to start a stand-alone shell:
 

src/conf.c

@@ -737,10 +737,6 @@ int conf_reload(void)
 
 	globfree(&gl);
 
-	/* Verify config, do we have at least one TTY available? */
-	if (tty_fallback(FINIT_CONF))
-		logit(LOG_WARNING, "warning, no getty enabled on local TTYs.");
-
 	/* Mark any reverse deps as chenaged. */
 	service_update_rdeps();
 

src/svc.c

@@ -433,7 +433,7 @@ svc_t *svc_find_by_tty(char *dev)
 {
 	svc_t *svc, *iter = NULL;
 
-	/* this is valid for fallback shells */
+	/* this is valid for fallback (notty) shells */
 	if (!dev)
 		return NULL;
 

src/tty.c

@@ -286,32 +286,6 @@ int tty_exec(svc_t *tty)
 	return run_getty2(dev, tty->cmd, args, tty->noclear, tty->nowait, tty->rlimit);
 }
 
-/*
- * Fallback shell if no TTYs are active
- */
-int tty_fallback(char *file)
-{
-	svc_t *svc, *iter = NULL;
-	size_t num = 0;
-
-	for (svc = svc_iterator(&iter, 1); svc; svc = svc_iterator(&iter, 0)) {
-		if (!svc_is_tty(svc) || svc_is_removed(svc))
-			continue;
-		num++;
-	}
-
-#ifdef FALLBACK_SHELL
-	char line[32] = "tty [12345789] notty noclear";
-
-	if (!num) {
-		_d("No TTY active in configuration, enabling fallback shell.");
-		return service_register(SVC_TYPE_TTY, line, global_rlimit, file);
-	}
-#endif
-
-	return num == 0;
-}
-
 /**
  * Local Variables:
  *  indent-tabs-mode: t

src/tty.h

@@ -51,7 +51,6 @@ int	 tty_parse_args   (char *cmdline, struct tty *tty);
 
 int	 tty_exists	  (char *dev);
 int	 tty_exec	  (svc_t *tty);
-int	 tty_fallback	  (char *file);
 
 #endif /* FINIT_TTY_H_ */