[PATCH v2 0/6] forking and threading

[Brandon Williams <bmwill@google.com>]

v2 does a bit of restructuring based on comments from reviewers.  I took the
patch by Eric and broke it up and tweaked it a bit to flow better with v2.  I
left out the part of Eric's patch which did signal manipulation as I wasn't
experienced enough to know what it was doing or why it was necessary.  Though I
believe the code is structured in such a way that Eric could make another patch
on top of this series with just the signal changes.

I switched to using 'execve' instead of 'execvpe' because 'execvpe' isn't a
portable call and doesn't work on systems like macOS.  This means that the path
resolution needs to be done by hand before forking (which there already existed
a function to do just that).

From what I can see, there are now no calls in the child process (after fork
and before exec/_exit) which are not Async-Signal-Safe.  This means that
fork/exec in a threaded context should work without deadlock and we could
potentially move to using vfork instead of fork, though I'll let others more
experienced make that decision.

Brandon Williams (6):
  t5550: use write_script to generate post-update hook
  run-command: prepare command before forking
  run-command: prepare child environment before forking
  run-command: don't die in child when duping /dev/null
  run-command: eliminate calls to error handling functions in child
  run-command: add note about forking and threading

 run-command.c              | 291 ++++++++++++++++++++++++++++++++++-----------
 t/t5550-http-fetch-dumb.sh |   5 +-
 2 files changed, 223 insertions(+), 73 deletions(-)

-- 
2.12.2.762.g0e3151a226-goog