Unicorn 0.94.0 - small fixes and new features

Unicorn is a HTTP server for Rack applications designed to only serve
fast clients on low-latency, high-bandwidth connections and take
advantage of features in Unix/Unix-like kernels. Slow clients should
only be served by placing a reverse proxy capable of fully buffering
both the the request and response in between Unicorn and slow clients.

Changes:

The HTTP parser is fix for oddly-aligned reads of trailers (this
technically affects headers, too, but is highly unlikely due to
our non-support of slow clients). This allows our HTTP parser
to better support very slow clients when used by other servers
(like Rainbows!). Fortunately this bug does not appear to lead
to any invalid memory accesses (and potential arbitrary code
execution).

FreeBSD (and possibly other *BSDs) support is improved and and
all the test cases pass under FreeBSD 7.2. Various flavors of
GNU/Linux remains our primary platform for development and
production.

New features added include the “working_directory” directive in
the configurator . Even without specifying a
“working_directory”, symlink-aware detection of the current path
no longer depends on /bin/sh so it should work out-of-the-box on
FreeBSD and Solaris and not just systems where /bin/sh is dash,
ksh93 or bash.

User-switching support is finally supported but only intended
for use in the after_fork hook of worker processes. Putting it
in the after_fork hook allows allows users to set things like
CPU affinity[1] on a per-worker basis before dropping
privileges. The master process retains all privileges it
started with.

The ENV[“RACK_ENV”] (process-wide) environment variable is now
both read and set for unicorn' in the same way RAILS_ENV is used byunicorn_rails’. This allows the Merb launcher to read
ENV[“RACK_ENV”] in config.ru. Other web servers already set
this and there may be applications or libraries that already
rely on this de facto standard.

Eric W. (26):
cleanup: avoid redundant error checks for fstat
test_helper: connect(2) may fail with EINVAL
GNUmakefile: fix non-portable tar(1) usage
tests: provide a pure Ruby setsid(8) equivalent
more portable symlink awareness for START_CTX[:cwd]
test_signals: avoid portability issues with fchmod(2)
cleanup error handling and make it less noisy
Do not override Dir.chdir in config files
configurator: add “working_directory” directive
configurator: working_directory is expanded
configurator: set ENV[“PWD”] with working_directory, too
configurator: working_directory affects pid, std{err,out}_paths
configurator: update documentation for working_directory
TODO: remove working_directory bit, done
Util.reopen_logs: remove needless Range
worker: user/group switching for after_fork hooks
Fix autoload of Etc in Worker for Ruby 1.9
bin/unicorn: allow RACK_ENV to be passed from parent
tests for RACK_ENV preservation
http: allow headers/trailers to be written byte-wise
http: extra test for bytewise chunked bodies
tee_input: do not clobber trailer buffer on partial uploads
test_exec: ensure master is killed after test
Util::tmpio returns a TmpIO that responds to #size
TODO: remove user-switching bit, done
unicorn 0.94.0

Wayne L. (1):
bin/unicorn: set ENV[“RACK_ENV”] on startup

[1] - Unicorn does not support CPU affinity directly, but it is
possible to load code that allows it inside after_fork hooks,
or even just call sched_tool(8).