init: if PID!=1, show clearer error message. move usage text closer to main()

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 137 insertions, 134 deletions

diff --git a/init/init.c b/init/init.c
index a7bbd5e64..0a0d503b5 100644
--- a/init/init.c
+++ b/init/init.c
@@ -108,138 +108,6 @@
 //config:	  Note that on Linux, init attempts to detect serial terminal and
 //config:	  sets TERM to "vt102" if one is found.
 
-//usage:#define init_trivial_usage
-//usage:       ""
-//usage:#define init_full_usage "\n\n"
-//usage:       "Init is the parent of all processes"
-//usage:
-//usage:#define init_notes_usage
-//usage:	"This version of init is designed to be run only by the kernel.\n"
-//usage:	"\n"
-//usage:	"BusyBox init doesn't support multiple runlevels. The runlevels field of\n"
-//usage:	"the /etc/inittab file is completely ignored by BusyBox init. If you want\n"
-//usage:	"runlevels, use sysvinit.\n"
-//usage:	"\n"
-//usage:	"BusyBox init works just fine without an inittab. If no inittab is found,\n"
-//usage:	"it has the following default behavior:\n"
-//usage:	"\n"
-//usage:	"	::sysinit:/etc/init.d/rcS\n"
-//usage:	"	::askfirst:/bin/sh\n"
-//usage:	"	::ctrlaltdel:/sbin/reboot\n"
-//usage:	"	::shutdown:/sbin/swapoff -a\n"
-//usage:	"	::shutdown:/bin/umount -a -r\n"
-//usage:	"	::restart:/sbin/init\n"
-//usage:	"\n"
-//usage:	"if it detects that /dev/console is _not_ a serial console, it will also run:\n"
-//usage:	"\n"
-//usage:	"	tty2::askfirst:/bin/sh\n"
-//usage:	"	tty3::askfirst:/bin/sh\n"
-//usage:	"	tty4::askfirst:/bin/sh\n"
-//usage:	"\n"
-//usage:	"If you choose to use an /etc/inittab file, the inittab entry format is as follows:\n"
-//usage:	"\n"
-//usage:	"	<id>:<runlevels>:<action>:<process>\n"
-//usage:	"\n"
-//usage:	"	<id>:\n"
-//usage:	"\n"
-//usage:	"		WARNING: This field has a non-traditional meaning for BusyBox init!\n"
-//usage:	"		The id field is used by BusyBox init to specify the controlling tty for\n"
-//usage:	"		the specified process to run on. The contents of this field are\n"
-//usage:	"		appended to \"/dev/\" and used as-is. There is no need for this field to\n"
-//usage:	"		be unique, although if it isn't you may have strange results. If this\n"
-//usage:	"		field is left blank, the controlling tty is set to the console. Also\n"
-//usage:	"		note that if BusyBox detects that a serial console is in use, then only\n"
-//usage:	"		entries whose controlling tty is either the serial console or /dev/null\n"
-//usage:	"		will be run. BusyBox init does nothing with utmp. We don't need no\n"
-//usage:	"		stinkin' utmp.\n"
-//usage:	"\n"
-//usage:	"	<runlevels>:\n"
-//usage:	"\n"
-//usage:	"		The runlevels field is completely ignored.\n"
-//usage:	"\n"
-//usage:	"	<action>:\n"
-//usage:	"\n"
-//usage:	"		Valid actions include: sysinit, respawn, askfirst, wait,\n"
-//usage:	"		once, restart, ctrlaltdel, and shutdown.\n"
-//usage:	"\n"
-//usage:	"		The available actions can be classified into two groups: actions\n"
-//usage:	"		that are run only once, and actions that are re-run when the specified\n"
-//usage:	"		process exits.\n"
-//usage:	"\n"
-//usage:	"		Run only-once actions:\n"
-//usage:	"\n"
-//usage:	"			'sysinit' is the first item run on boot. init waits until all\n"
-//usage:	"			sysinit actions are completed before continuing. Following the\n"
-//usage:	"			completion of all sysinit actions, all 'wait' actions are run.\n"
-//usage:	"			'wait' actions, like 'sysinit' actions, cause init to wait until\n"
-//usage:	"			the specified task completes. 'once' actions are asynchronous,\n"
-//usage:	"			therefore, init does not wait for them to complete. 'restart' is\n"
-//usage:	"			the action taken to restart the init process. By default this should\n"
-//usage:	"			simply run /sbin/init, but can be a script which runs pivot_root or it\n"
-//usage:	"			can do all sorts of other interesting things. The 'ctrlaltdel' init\n"
-//usage:	"			actions are run when the system detects that someone on the system\n"
-//usage:	"			console has pressed the CTRL-ALT-DEL key combination. Typically one\n"
-//usage:	"			wants to run 'reboot' at this point to cause the system to reboot.\n"
-//usage:	"			Finally the 'shutdown' action specifies the actions to taken when\n"
-//usage:	"			init is told to reboot. Unmounting filesystems and disabling swap\n"
-//usage:	"			is a very good here.\n"
-//usage:	"\n"
-//usage:	"		Run repeatedly actions:\n"
-//usage:	"\n"
-//usage:	"			'respawn' actions are run after the 'once' actions. When a process\n"
-//usage:	"			started with a 'respawn' action exits, init automatically restarts\n"
-//usage:	"			it. Unlike sysvinit, BusyBox init does not stop processes from\n"
-//usage:	"			respawning out of control. The 'askfirst' actions acts just like\n"
-//usage:	"			respawn, except that before running the specified process it\n"
-//usage:	"			displays the line \"Please press Enter to activate this console.\"\n"
-//usage:	"			and then waits for the user to press enter before starting the\n"
-//usage:	"			specified process.\n"
-//usage:	"\n"
-//usage:	"		Unrecognized actions (like initdefault) will cause init to emit an\n"
-//usage:	"		error message, and then go along with its business. All actions are\n"
-//usage:	"		run in the order they appear in /etc/inittab.\n"
-//usage:	"\n"
-//usage:	"	<process>:\n"
-//usage:	"\n"
-//usage:	"		Specifies the process to be executed and its command line.\n"
-//usage:	"\n"
-//usage:	"Example /etc/inittab file:\n"
-//usage:	"\n"
-//usage:	"	# This is run first except when booting in single-user mode\n"
-//usage:	"	#\n"
-//usage:	"	::sysinit:/etc/init.d/rcS\n"
-//usage:	"	\n"
-//usage:	"	# /bin/sh invocations on selected ttys\n"
-//usage:	"	#\n"
-//usage:	"	# Start an \"askfirst\" shell on the console (whatever that may be)\n"
-//usage:	"	::askfirst:-/bin/sh\n"
-//usage:	"	# Start an \"askfirst\" shell on /dev/tty2-4\n"
-//usage:	"	tty2::askfirst:-/bin/sh\n"
-//usage:	"	tty3::askfirst:-/bin/sh\n"
-//usage:	"	tty4::askfirst:-/bin/sh\n"
-//usage:	"	\n"
-//usage:	"	# /sbin/getty invocations for selected ttys\n"
-//usage:	"	#\n"
-//usage:	"	tty4::respawn:/sbin/getty 38400 tty4\n"
-//usage:	"	tty5::respawn:/sbin/getty 38400 tty5\n"
-//usage:	"	\n"
-//usage:	"	\n"
-//usage:	"	# Example of how to put a getty on a serial line (for a terminal)\n"
-//usage:	"	#\n"
-//usage:	"	#::respawn:/sbin/getty -L ttyS0 9600 vt100\n"
-//usage:	"	#::respawn:/sbin/getty -L ttyS1 9600 vt100\n"
-//usage:	"	#\n"
-//usage:	"	# Example how to put a getty on a modem line\n"
-//usage:	"	#::respawn:/sbin/getty 57600 ttyS2\n"
-//usage:	"	\n"
-//usage:	"	# Stuff to do when restarting the init process\n"
-//usage:	"	::restart:/sbin/init\n"
-//usage:	"	\n"
-//usage:	"	# Stuff to do before rebooting\n"
-//usage:	"	::ctrlaltdel:/sbin/reboot\n"
-//usage:	"	::shutdown:/bin/umount -a -r\n"
-//usage:	"	::shutdown:/sbin/swapoff -a\n"
-
 #include "libbb.h"
 #include <syslog.h>
 #include <paths.h>
@@ -1095,9 +963,9 @@ int init_main(int argc UNUSED_PARAM, char **argv)
 	if (!DEBUG_INIT) {
 		/* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
 		if (getpid() != 1
-		 && (!ENABLE_FEATURE_INITRD || !strstr(applet_name, "linuxrc"))
+		 && (!ENABLE_FEATURE_INITRD || applet_name[0] != 'l') /* not linuxrc? */
 		) {
-			bb_show_usage();
+			bb_error_msg_and_die("must be run as PID 1");
 		}
 #ifdef RB_DISABLE_CAD
 		/* Turn off rebooting via CTL-ALT-DEL - we get a
@@ -1286,3 +1154,138 @@ int init_main(int argc UNUSED_PARAM, char **argv)
 		}
 	} /* while (1) */
 }
+
+//usage:#define linuxrc_trivial_usage NOUSAGE_STR
+//usage:#define linuxrc_full_usage ""
+
+//usage:#define init_trivial_usage
+//usage:       ""
+//usage:#define init_full_usage "\n\n"
+//usage:       "Init is the parent of all processes"
+//usage:
+//usage:#define init_notes_usage
+//usage:	"This version of init is designed to be run only by the kernel.\n"
+//usage:	"\n"
+//usage:	"BusyBox init doesn't support multiple runlevels. The runlevels field of\n"
+//usage:	"the /etc/inittab file is completely ignored by BusyBox init. If you want\n"
+//usage:	"runlevels, use sysvinit.\n"
+//usage:	"\n"
+//usage:	"BusyBox init works just fine without an inittab. If no inittab is found,\n"
+//usage:	"it has the following default behavior:\n"
+//usage:	"\n"
+//usage:	"	::sysinit:/etc/init.d/rcS\n"
+//usage:	"	::askfirst:/bin/sh\n"
+//usage:	"	::ctrlaltdel:/sbin/reboot\n"
+//usage:	"	::shutdown:/sbin/swapoff -a\n"
+//usage:	"	::shutdown:/bin/umount -a -r\n"
+//usage:	"	::restart:/sbin/init\n"
+//usage:	"\n"
+//usage:	"if it detects that /dev/console is _not_ a serial console, it will also run:\n"
+//usage:	"\n"
+//usage:	"	tty2::askfirst:/bin/sh\n"
+//usage:	"	tty3::askfirst:/bin/sh\n"
+//usage:	"	tty4::askfirst:/bin/sh\n"
+//usage:	"\n"
+//usage:	"If you choose to use an /etc/inittab file, the inittab entry format is as follows:\n"
+//usage:	"\n"
+//usage:	"	<id>:<runlevels>:<action>:<process>\n"
+//usage:	"\n"
+//usage:	"	<id>:\n"
+//usage:	"\n"
+//usage:	"		WARNING: This field has a non-traditional meaning for BusyBox init!\n"
+//usage:	"		The id field is used by BusyBox init to specify the controlling tty for\n"
+//usage:	"		the specified process to run on. The contents of this field are\n"
+//usage:	"		appended to \"/dev/\" and used as-is. There is no need for this field to\n"
+//usage:	"		be unique, although if it isn't you may have strange results. If this\n"
+//usage:	"		field is left blank, the controlling tty is set to the console. Also\n"
+//usage:	"		note that if BusyBox detects that a serial console is in use, then only\n"
+//usage:	"		entries whose controlling tty is either the serial console or /dev/null\n"
+//usage:	"		will be run. BusyBox init does nothing with utmp. We don't need no\n"
+//usage:	"		stinkin' utmp.\n"
+//usage:	"\n"
+//usage:	"	<runlevels>:\n"
+//usage:	"\n"
+//usage:	"		The runlevels field is completely ignored.\n"
+//usage:	"\n"
+//usage:	"	<action>:\n"
+//usage:	"\n"
+//usage:	"		Valid actions include: sysinit, respawn, askfirst, wait,\n"
+//usage:	"		once, restart, ctrlaltdel, and shutdown.\n"
+//usage:	"\n"
+//usage:	"		The available actions can be classified into two groups: actions\n"
+//usage:	"		that are run only once, and actions that are re-run when the specified\n"
+//usage:	"		process exits.\n"
+//usage:	"\n"
+//usage:	"		Run only-once actions:\n"
+//usage:	"\n"
+//usage:	"			'sysinit' is the first item run on boot. init waits until all\n"
+//usage:	"			sysinit actions are completed before continuing. Following the\n"
+//usage:	"			completion of all sysinit actions, all 'wait' actions are run.\n"
+//usage:	"			'wait' actions, like 'sysinit' actions, cause init to wait until\n"
+//usage:	"			the specified task completes. 'once' actions are asynchronous,\n"
+//usage:	"			therefore, init does not wait for them to complete. 'restart' is\n"
+//usage:	"			the action taken to restart the init process. By default this should\n"
+//usage:	"			simply run /sbin/init, but can be a script which runs pivot_root or it\n"
+//usage:	"			can do all sorts of other interesting things. The 'ctrlaltdel' init\n"
+//usage:	"			actions are run when the system detects that someone on the system\n"
+//usage:	"			console has pressed the CTRL-ALT-DEL key combination. Typically one\n"
+//usage:	"			wants to run 'reboot' at this point to cause the system to reboot.\n"
+//usage:	"			Finally the 'shutdown' action specifies the actions to taken when\n"
+//usage:	"			init is told to reboot. Unmounting filesystems and disabling swap\n"
+//usage:	"			is a very good here.\n"
+//usage:	"\n"
+//usage:	"		Run repeatedly actions:\n"
+//usage:	"\n"
+//usage:	"			'respawn' actions are run after the 'once' actions. When a process\n"
+//usage:	"			started with a 'respawn' action exits, init automatically restarts\n"
+//usage:	"			it. Unlike sysvinit, BusyBox init does not stop processes from\n"
+//usage:	"			respawning out of control. The 'askfirst' actions acts just like\n"
+//usage:	"			respawn, except that before running the specified process it\n"
+//usage:	"			displays the line \"Please press Enter to activate this console.\"\n"
+//usage:	"			and then waits for the user to press enter before starting the\n"
+//usage:	"			specified process.\n"
+//usage:	"\n"
+//usage:	"		Unrecognized actions (like initdefault) will cause init to emit an\n"
+//usage:	"		error message, and then go along with its business. All actions are\n"
+//usage:	"		run in the order they appear in /etc/inittab.\n"
+//usage:	"\n"
+//usage:	"	<process>:\n"
+//usage:	"\n"
+//usage:	"		Specifies the process to be executed and its command line.\n"
+//usage:	"\n"
+//usage:	"Example /etc/inittab file:\n"
+//usage:	"\n"
+//usage:	"	# This is run first except when booting in single-user mode\n"
+//usage:	"	#\n"
+//usage:	"	::sysinit:/etc/init.d/rcS\n"
+//usage:	"	\n"
+//usage:	"	# /bin/sh invocations on selected ttys\n"
+//usage:	"	#\n"
+//usage:	"	# Start an \"askfirst\" shell on the console (whatever that may be)\n"
+//usage:	"	::askfirst:-/bin/sh\n"
+//usage:	"	# Start an \"askfirst\" shell on /dev/tty2-4\n"
+//usage:	"	tty2::askfirst:-/bin/sh\n"
+//usage:	"	tty3::askfirst:-/bin/sh\n"
+//usage:	"	tty4::askfirst:-/bin/sh\n"
+//usage:	"	\n"
+//usage:	"	# /sbin/getty invocations for selected ttys\n"
+//usage:	"	#\n"
+//usage:	"	tty4::respawn:/sbin/getty 38400 tty4\n"
+//usage:	"	tty5::respawn:/sbin/getty 38400 tty5\n"
+//usage:	"	\n"
+//usage:	"	\n"
+//usage:	"	# Example of how to put a getty on a serial line (for a terminal)\n"
+//usage:	"	#\n"
+//usage:	"	#::respawn:/sbin/getty -L ttyS0 9600 vt100\n"
+//usage:	"	#::respawn:/sbin/getty -L ttyS1 9600 vt100\n"
+//usage:	"	#\n"
+//usage:	"	# Example how to put a getty on a modem line\n"
+//usage:	"	#::respawn:/sbin/getty 57600 ttyS2\n"
+//usage:	"	\n"
+//usage:	"	# Stuff to do when restarting the init process\n"
+//usage:	"	::restart:/sbin/init\n"
+//usage:	"	\n"
+//usage:	"	# Stuff to do before rebooting\n"
+//usage:	"	::ctrlaltdel:/sbin/reboot\n"
+//usage:	"	::shutdown:/bin/umount -a -r\n"
+//usage:	"	::shutdown:/sbin/swapoff -a\n"