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| | # -*- encoding: binary -*-
# Copyright (C) 2015-2016 all contributors <yahns-public@yhbt.net>
# License: GPL-3.0+ (https://www.gnu.org/licenses/gpl-3.0.txt)
# frozen_string_literal: true
# loaded by yahns/proxy_pass, this relies on Yahns::HttpResponse for
# constants.
module Yahns::HttpResponse # :nodoc:
# write everything in buf to our client socket (or wbuf, if it exists)
# it may return a newly-created wbuf or nil
def proxy_write(wbuf, buf, alive)
unless wbuf
# no write buffer, try to write directly to the client socket
case rv = String === buf ? kgio_trywrite(buf) : kgio_trywritev(buf)
when nil then return # done writing buf, likely
when String, Array # partial write, hope the skb grows
buf = rv
when :wait_writable, :wait_readable
wbuf = Yahns::Wbuf.new(nil, alive, self.class.output_buffer_tmpdir, rv)
buf = buf.join if Array === buf
break
end while true
end
wbuf.wbuf_write(self, buf)
wbuf.busy ? wbuf : nil
end
def proxy_err_response(code, req_res, exc, wbuf)
logger = @hs.env['rack.logger']
case exc
when nil
logger.error('premature upstream EOF')
when Kcar::ParserError
logger.error("upstream response error: #{exc.message}")
else
Yahns::Log.exception(logger, 'upstream error', exc)
end
# try to write something, but don't care if we fail
Integer === code and
kgio_trywrite("HTTP/1.1 #{code} #{
Rack::Utils::HTTP_STATUS_CODES[code]}\r\n\r\n") rescue nil
shutdown rescue nil
@input = @input.close if @input
# this is safe ONLY because we are in an :ignore state after
# Fdmap#forget when we got hijacked:
close
nil # signal close of req_res from yahns_step in yahns/proxy_pass.rb
ensure
wbuf.wbuf_abort if wbuf
end
def wait_on_upstream(req_res, alive, wbuf)
req_res.resbuf = wbuf || Yahns::Wbuf.new(nil, alive,
self.class.output_buffer_tmpdir,
false)
:wait_readable # self remains in :ignore, wait on upstream
end
def proxy_res_headers(res)
status, headers = res
code = status.to_i
msg = Rack::Utils::HTTP_STATUS_CODES[code]
env = @hs.env
have_body = !Rack::Utils::STATUS_WITH_NO_ENTITY_BODY.include?(code) &&
env['REQUEST_METHOD'] != 'HEAD'.freeze
flags = MSG_DONTWAIT
alive = @hs.next? && self.class.persistent_connections
term = false
response_headers = env['yahns.proxy_pass.response_headers']
res = "HTTP/1.1 #{msg ? %Q(#{code} #{msg}) : status}\r\n".dup
headers.each do |key,value| # n.b.: headers is an Array of 2-element Arrays
case key
when /\A(?:Connection|Keep-Alive)\z/i
next # do not let some upstream headers leak through
when %r{\AContent-Length\z}i
term = true
flags |= MSG_MORE if have_body && value.to_i > 0
when %r{\ATransfer-Encoding\z}i
term = true if value =~ /\bchunked\b/i
end
# response header mapping
case val = response_headers[key]
when :ignore
next
when String
value = val
end
res << "#{key}: #{value}\r\n"
end
# For now, do not add a Date: header, assume upstream already did it
# but do not care if they did not
# chunk the response ourselves if the client supports it,
# but the backend does not terminate properly
if alive && ! term
if env['HTTP_VERSION'] == 'HTTP/1.1'.freeze
res << "Transfer-Encoding: chunked\r\n".freeze
else # we can't persist HTTP/1.0 and HTTP/0.9 w/o Content-Length
alive = false
end
end
res << (alive ? "Connection: keep-alive\r\n\r\n".freeze
: "Connection: close\r\n\r\n".freeze)
# send the headers
case rv = kgio_syssend(res, flags)
when nil then break # all done, likely
when String # partial write, highly unlikely
flags = MSG_DONTWAIT
res = rv # hope the skb grows
when :wait_writable, :wait_readable # highly unlikely in real apps
wbuf = proxy_write(nil, res, alive)
break # keep buffering as much as possible
end while true
[ alive, wbuf, have_body ]
end
def proxy_read_body(tip, kcar, req_res, alive, wbuf)
chunk = ''.dup if kcar.chunked?
len = kcar.body_bytes_left
rbuf = Thread.current[:yahns_rbuf]
case tmp = tip.shift || req_res.kgio_tryread(0x2000, rbuf)
when String
if len
kcar.body_bytes_left -= tmp.size # progress for body_eof? => true
elsif chunk
kcar.filter_body(chunk, rbuf = tmp) # progress for body_eof? => true
next if chunk.empty? # call req_res.kgio_tryread for more
tmp = chunk_out(chunk)
elsif alive # HTTP/1.0 upstream, HTTP/1.1 client
tmp = chunk_out(tmp)
# else # HTTP/1.0 upstream, HTTP/1.0 client, do nothing
end
wbuf = proxy_write(wbuf, tmp, alive)
chunk.clear if chunk
when nil # EOF
# HTTP/1.1 upstream, unexpected premature EOF:
return proxy_err_response(nil, req_res, nil, wbuf) if len || chunk
# HTTP/1.0 upstream:
wbuf = proxy_write(wbuf, "0\r\n\r\n".freeze, true) if alive
req_res.shutdown
break
when :wait_readable
return wait_on_upstream(req_res, alive, wbuf)
end until kcar.body_eof?
if chunk
# tip is an empty array and becomes trailer storage
req_res.proxy_trailers = [ rbuf.dup, tip ]
return proxy_read_trailers(kcar, req_res, alive, wbuf)
end
proxy_busy_mod(wbuf, alive)
end
def proxy_read_trailers(kcar, req_res, alive, wbuf)
chunk, tlr = req_res.proxy_trailers
rbuf = Thread.current[:yahns_rbuf]
until kcar.trailers(tlr, chunk)
case rv = req_res.kgio_tryread(0x2000, rbuf)
when String
chunk << rv
when :wait_readable
return wait_on_upstream(req_res, alive, wbuf)
when nil # premature EOF
return proxy_err_response(nil, req_res, nil, wbuf)
end # no loop here
end
wbuf = proxy_write(wbuf, trailer_out(tlr), alive)
proxy_busy_mod(wbuf, alive)
end
# start streaming the response once upstream is done sending headers to us.
# returns :wait_readable if we need to read more from req_res
# returns :ignore if we yield control to the client(self)
# returns nil if completely done
def proxy_response_start(res, tip, kcar, req_res)
alive, wbuf, have_body = proxy_res_headers(res)
tip = tip.empty? ? [] : [ tip ]
if have_body
req_res.proxy_trailers = nil # define to avoid uninitialized warnings
return proxy_read_body(tip, kcar, req_res, alive, wbuf)
end
# all done reading response from upstream, req_res will be discarded
# when we return nil:
proxy_busy_mod(wbuf, alive)
rescue => e
proxy_err_response(502, req_res, e, wbuf)
end
def proxy_response_finish(kcar, wbuf, req_res)
alive = wbuf.wbuf_persist
req_res.proxy_trailers ? proxy_read_trailers(kcar, req_res, alive, wbuf)
: proxy_read_body([], kcar, req_res, alive, wbuf)
end
def proxy_wait_next(qflags)
Thread.current[:yahns_fdmap].remember(self)
# We must allocate a new, empty request object here to avoid a TOCTTOU
# in the following timeline
#
# original thread: | another thread
# HttpClient#yahns_step |
# r = k.app.call(env = @hs.env) # socket hijacked into epoll queue
# <thread is scheduled away> | epoll_wait readiness
# | ReqRes#yahns_step
# | proxy dispatch ...
# | proxy_busy_mod
# ************************** DANGER BELOW ********************************
# | HttpClient#yahns_step
# | # clears env
# sees empty env: |
# return :ignore if env.include?('rack.hijack_io') |
#
# In other words, we cannot touch the original env seen by the
# original thread since it must see the 'rack.hijack_io' value
# because both are operating in the same Yahns::HttpClient object.
# This will happen regardless of GVL existence
hs = Unicorn::HttpRequest.new
hs.buf.replace(@hs.buf)
@hs = hs
# n.b. we may not touch anything in this object once we call queue_mod,
# another thread is likely to take it!
Thread.current[:yahns_queue].queue_mod(self, qflags)
end
def proxy_busy_mod(wbuf, alive)
busy = wbuf.busy if wbuf
if busy
# we are completely done reading and buffering the upstream response,
# but have not completely written the response to the client,
# yield control to the client socket:
@state = wbuf
proxy_wait_next(case busy
when :wait_readable then Yahns::Queue::QEV_RD
when :wait_writable then Yahns::Queue::QEV_WR
else
raise "BUG: invalid wbuf.busy: #{busy.inspect}"
end)
# no touching self after proxy_wait_next, we may be running
# HttpClient#yahns_step in a different thread at this point
else
case http_response_done(alive)
when :wait_readable then proxy_wait_next(Yahns::Queue::QEV_RD)
when :wait_writable then proxy_wait_next(Yahns::Queue::QEV_WR)
when :close then close
end
end
nil # signal close for ReqRes#yahns_step
end
# n.b.: we can use String#size for optimized dispatch under YARV instead
# of String#bytesize because all the IO read methods return a binary
# string when given a maximum read length
def chunk_out(buf)
[ "#{buf.size.to_s(16)}\r\n", buf, "\r\n".freeze ]
end
def trailer_out(tlr)
"0\r\n#{tlr.map! do |k,v| "#{k}: #{v}\r\n" end.join}\r\n"
end
end
|