There seems to be a compatibility problems with Rails +
Rack::Deflater; so we revert this incompatibility.

This effectively reverts r65922; but keeps the bugfixes to
better support non-blocking sockets and pipes for future use.

[Bug #15356] [Bug #14968]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66093 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

All normal Ruby IO methods (IO#read, IO#gets, IO#write, ...) are
all capable of appearing to be "blocking" when presented with a
file description with the O_NONBLOCK flag set; so there is
little risk of incompatibility within Ruby-using programs.

The biggest compatibility risk is when spawning external
programs.  As a result, stdin, stdout, and stderr are now always
made blocking before exec-family calls.

This change will make an event-oriented MJIT usable if it is
waiting on pipes on POSIX_like platforms.

It is ALSO necessary to take advantage of (proposed lightweight
concurrency (aka "auto-Fiber") or any similar proposal for
network concurrency: https://bugs.ruby-lang.org/issues/13618

Named-pipe (FIFO) are NOT yet non-blocking by default since
they are rarely-used and may introduce compatibility problems
and extra syscall overhead for a common path.

Please revert this commit if there are problems and if I am afk
since I am afk a lot, lately.

[ruby-core:89950] [Bug #14968]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65922 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

IO#read_nonblock and IO#write_nonblock take into account
buffered data, so the Linux-only BasicSocket#read_nonblock
and BasicSocket#write_nonblock methods must, too.

This bug was only introduced in r58400
("socket: avoid fcntl for read/write_nonblock on Linux")
and does not affect any stable release.

* ext/socket/basicsocket.c (rsock_init_basicsocket):
* ext/socket/init.c (rsock_s_recvfrom_nonblock):
* ext/socket/init.c (rsock_init_socket_init):
* ext/socket/lib/socket.rb (def read_nonblock):
* ext/socket/lib/socket.rb (def write_nonblock):
* ext/socket/rubysocket.h (static inline void rsock_maybe_wait_fd):
* test/socket/test_basicsocket.rb (def test_read_write_nonblock):
  [Feature #13362]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60496 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

Binding to a potentially public IP in a test can cause problems
if hit by a random port scanner or something...

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58725 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

On some systems with slower local sockets, :wait_readable may
happen and we should wait on it to drain the socket.
This is a possible fix for https://bugs.ruby-lang.org/issues/13491

* test/socket/test_basicsocket.rb (test_read_write_nonblock):
  handle :wait_readable on read_nonblock

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58437 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

On platforms where MSG_DONTWAIT works reliably on all sockets
(so far, I know of Linux), we can avoid fcntl syscalls and
implement IO#write_nonblock and IO#read_nonblock in terms of the
socket-specific send and recv family of syscalls.

This avoids side effects on the socket, and also encourages
generic code to be written in cases where IO wrappers like
OpenSSL::SSL::SSLSocket are used.

Perhaps in the future, side-effect-free non-blocking I/O can
be standard on all files and OSes: https://cr.yp.to/unix/nonblock.html

* ext/socket/lib/socket.rb (read_nonblock, write_nonblock):
  Linux-specific wrapper without side effects
  [ruby-core:80780] [Feature #13362]
* test/socket/test_basicsocket.rb (test_read_write_nonblock):
  new test

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58400 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* test/rinda/test_rinda.rb (test_make_socket_ipv4_multicast):
  The fifth argument to getsockopt(2) should be modified to
  indicate the actual size of the value on return,
  but not in AIX. This is a know bug. Skip related tests.
* test/rinda/test_rinda.rb (test_ring_server_ipv4_multicast):
  ditto.
* test/rinda/test_rinda.rb (test_make_socket_unicast): ditto.
* test/socket/test_basicsocket.rb (test_getsockopt): ditto.
* test/socket/test_sockopt.rb (test_bool): ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@54004 b2dd03c8-39d4-4d8f-98ff-823fe69b080e