todo

sysvinit--linux系统下的init

There are several things on the wishlist. See also the "wishlist" bugs filed
against sysvinit in the debian bugs system (http://www.debian.org/Bugs/).

1. A special target for kbrequest, so that extra CHILDs are
  created (each one needs its own utmp/wtmp bookkeeping)
2. Extend the initreq.h interface?
3. Add GNU last long options to last

4. Write all boot messages to a logfile
   Problem: TIOCCONS ioctl redirects console output, it doesn't copy it.
   I think this is not easily possible without kernel support.
   I do not like the idea of booting with a pseudo tty as console and
   a redirect process behind it writing to both the real console and a
   logfile - too fragile.