applying patch from bug 24:

0000024 03-16-05 patch: allow init to set controlling tty

init/Config.in

@@ -43,6 +43,17 @@ config CONFIG_FEATURE_INIT_SWAPON
 	  If the system has less than one megabyte of total memory, init
 	  will run '/sbin/swapon -a' to add swap memory.
 
+config CONFIG_FEATURE_INIT_SCTTY
+	bool "  Support running commands with a controlling-tty?"
+	default n
+	depends on CONFIG_INIT
+	help
+	  If this option is enabled a command starting with hyphen (-)
+	  is run in its own session (setsid(2)) and possibly with a
+	  controlling tty (TIOCSCTTY).  This is not the traditional init
+	  behavour, but is often what you want in an embedded system where
+	  the console is only accessed during development or for maintenance.
+
 config CONFIG_FEATURE_EXTRA_QUIET
 	bool "  Should init be _extra_ quiet on boot?"
 	default y

init/init.c

@@ -577,6 +577,13 @@ static pid_t run(const struct init_action *a)
 				cmd[0][0] = '-';
 				strcpy(cmd[0] + 1, s);
 			}
+#ifdef CONFIG_FEATURE_INIT_SCTTY
+			/* Establish this process as session leader and
+			 * (attempt) to make the tty (if any) a controlling tty.
+			 */
+			(void) setsid();
+			(void) ioctl(0, TIOCSCTTY, 0/*don't steal it*/);
+#endif
 		}
 
 #if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__)