I'm trying to automatically start a process when I enter runlevel 1 by init 1. It's a watchdog which has to send a life signal all the time therefore in runlevel 1 too! But when runlevel 1 is entered each process is killed and the system switches to runlevel S. I tried to tell linux to start my process by update-rc.d -f watchdog 99 1 S .. The resulting entries in /etc/rc1.d/ and /etc/rcS.d/ are:
/etc/rc1.d/:
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S30killprocs -> ../init.d/killprocs
S90single -> ../init.d/single
S99watchdog -> ../init.d/watchdog
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/etc/rcS.d/:
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S01glibc.sh -> ../init.d/glibc.sh
S02hostname.sh -> ../init.d/hostname.sh
S99watchdog -> ../init.d/watchdog
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A ps ax after runlevel 1 was entered sadfully doesn't return my watchdog process. I have to start it manually.
PID TTY STAT TIME COMMAND
1 ? Ss 0:00 init [S]
2 ? S 0:00 [kthreadd]
3 ? S 0:00 [ksoftirqd/0]
4 ? S 0:00 [kworker/0:0]
5 ? S 0:00 [kworker/u:0]
6 ? S 0:00 [rcu_kthread]
7 ? S< 0:00 [khelper]
8 ? S 0:00 [kworker/u:1]
104 ? S 0:00 [sync_supers]
106 ? S 0:00 [bdi-default]
108 ? S< 0:00 [kblockd]
119 ? S 0:00 [khubd]
219 ? S 0:00 [kswapd0]
220 ? S 0:00 [fsnotify_mark]
221 ? S< 0:00 [aio]
314 ? S< 0:00 [scsi_tgtd]
347 ? S< 0:00 [kpsmoused]
349 ? S 0:00 [kworker/0:1]
366 ? S 0:00 [w1_bus_master1]
390 ? S 0:00 [mmcqd/0]
395 ? S 0:00 [jbd2/mmcblk0p2-]
396 ? S< 0:00 [ext4-dio-unwrit]
475 ? S 0:00 [flush-179:0]
4532 ttyS0 Ss 0:00 init [S]
4533 ttyS0 S 0:00 bash
4536 ttyS0 R+ 0:00 ps ax
The system I'm working on is Debian GNU/Linux 5.0 debarm (embedded). Any hints or solution? Thank you.
I solved it by adding following line into /etc/inittab:
~~:S:wait:/etc/init.d/watchdog start
~~:S:wait:/sbin/sulogin
Note: It must be before /sbin/sulogin.