Rainbow 0.7.12 Announcement

[Michael Stone]

Folks,

I've released a new rainbow, version 0.7.12 into Joyride in order to
solicit more widespread testing of some changes that I'd like to
incorporate into our next release. This version has some tasty things
like
 
 - delayed rainbow startup (which will allow X to win the rainbow/X
   startup race [#6797] more frequently) contributed by Blake Setlow, 

 - "fail-safe" handling of preloading-related import errors, and
   
 - a compatibility patch which makes $HOME writable by activities by
   setting $HOME and $SAR/instance equal to one another.

The final patch requires that we diverge from the version-1-spool-format
used by previous versions of rainbow. User applications which
automatically always follow symlinks should require no changes; however,
prior versions of Rainbow's uid garbage collector will complain noisily
at boot and will probably be unable to collect uids allocated by
rainbow-0.7.12 or later. Prior versions of Rainbow may become unable to
launch activities which have been launched by rainbow-0.7.12 or later.

If either of these issues sound like trouble, we can bump the spool
format version number (i.e. start locating version 2 spools in
/home/olpc/isolation/2/), provide a migration tool, and propagate the
change throughout client software. (The only software that I know of
which cares is the DataStore, and it's easily patched.)

Comments?

Michael

P.S. - Further review of the diffs from the rainbow-0.7.11 to
rainbow-0.7.12 tags in the security repo is quite welcome. Please don't
be shy if you see ways that this code can be improved!