dinit/TODO

For version 0.17:
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* Limit memory use by control connections. Currently clients have command responses queued without
  limit; it would be better to stop accepting new commands once a certain amount of response is
  buffered. 
* Externally triggered services (to represent devices etc). Such services will not reach STARTED
  state unless the external trigger occurs (eg "dinitctl trigger servicename", details to be
  determined).

For version 1.0 (release requirements):
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* Be able to boot and shutdown Linux and FreeBSD (or OpenBSD).
* Documentation must be complete (mostly done; will need updates as other items are completed).


Maybe for 1.0?
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* on shutdown, after a long interval with no activity, display information about
  services we are waiting on (and/or, do this when prompted via ^C or C-A-D?)
* Proper support for socket activation?
* Chaining of service process input/output?


For later (post 1.0):
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* jails support
* On linux when running with PID != 1, write PID to /proc/sys/kernel/cad_pid so
  that we still receive SIGINT from ctrl+alt+del (must be done after /proc is
  mounted, possibly could be left to a service script)
* Perhaps need a way to prevent script services from re-starting.
  (eg there's no need to mount filesystems twice; there might be various other
   system initialisations that can't or shouldn't really be "undone" and so do
   not need to be re-done).
* Internationalisation
* A service can prevent shutdown/reboot by failing to stop. Maybe make
  multiple CTRL-ALT-DEL presses (or ^C since that's more portable) commence
  immediate shutdown (or launch a simple control interface).
* When we take down a service or tty session, it would be ideal if we could kill
  the whole process tree, not just the leader process (need cgroups or pid
  namespace or other mechanism).
* Allow logging tasks to memory (growing or circular buffer) and later
  switching to disk logging (allows for filesystem mounted readonly on boot).
  But perhaps this really the responsibility of another daemon.
* Allow running services with different resource limits, chroot, cgroups,
  namespaces (pid/fs/uid), etc
* Support chaining service output to another process (logger) input; if the
  service dies the file descriptor of its stdout isn't closed and is reassigned
  when the service is restarted, so that minimal output is lost.
  - even more, it would be nice if a single logger process could be responsible
    for receiving output from multiple services. This would require some kind of
    protocol for passing new output descriptors to the logger (for when a
    service starts).
* dinitcheck should be able to resolve variable substitutions using variables from running dinit.


Even later / Maybe never:
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* Support recognising /etc/init.d services automatically (as script services, with
  no dependency management - or upstart compatible dependency management)
  Also BSD's rc.d style scripts (PROVIDE, REQUIRE).
* Place some reasonable, soft limit on the number of services to be started
  simultaneously, to prevent thrashing. Services that are taking a long time
  to start don't count to the limit. Maybe use CPU/IO usage as a controlling
  factor.
* Cron-like tasks (if started, they run a sub-task periodically. Stopping the
  task will wait until the sub-task is complete). 
* Allow to run services attached to virtual tty, allow connection to that tty (ala "screen").
* SystemD-like handling of filesystem mounts (see autofs documentation in kernel)
  i.e. a mount point gets an autofs attached, and lazily gets mounted when accessed
  (or is mounted in parallel). Probably put the functionality in a separate daemon.