From dbf0c0620252d3a0d6d0c0e38cafe41ad24b959f Mon Sep 17 00:00:00 2001 From: normal Date: Wed, 19 Apr 2017 01:08:16 +0000 Subject: socket: avoid fcntl for read/write_nonblock on Linux 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 --- ext/socket/lib/socket.rb | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'ext') diff --git a/ext/socket/lib/socket.rb b/ext/socket/lib/socket.rb index de5eda3991..8127009fff 100644 --- a/ext/socket/lib/socket.rb +++ b/ext/socket/lib/socket.rb @@ -442,6 +442,24 @@ class BasicSocket < IO scm_rights: false, exception: true) __recvmsg_nonblock(dlen, flags, clen, scm_rights, exception) end + + # Linux-specific optimizations to avoid fcntl for IO#read_nonblock + # and IO#write_nonblock using MSG_DONTWAIT + # Do other platforms suport MSG_DONTWAIT reliably? + if RUBY_PLATFORM =~ /linux/ && Socket.const_defined?(:MSG_DONTWAIT) + def read_nonblock(len, str = nil, exception: true) # :nodoc: + case rv = __recv_nonblock(len, 0, str, exception) + when '' # recv_nonblock returns empty string on EOF + exception ? raise(EOFError, 'end of file reached') : nil + else + rv + end + end + + def write_nonblock(buf, exception: true) # :nodoc: + __sendmsg_nonblock(buf, 0, nil, nil, exception) + end + end end class Socket < BasicSocket -- cgit v1.2.3