From 86b2f925112eae59c29cf939d86c4313e854fc2d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Patrick=20L=C3=BChne?= <patrick@luehne.de>
Date: Sun, 24 May 2020 04:30:04 +0200
Subject: [PATCH] Initial commit

---
 github-fast-env.rb  | 161 ++++++++++++++++++++++++++++++++++
 github-fast-envd.rb | 204 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 365 insertions(+)
 create mode 100755 github-fast-env.rb
 create mode 100755 github-fast-envd.rb

diff --git a/github-fast-env.rb b/github-fast-env.rb
new file mode 100755
index 0000000..a6a561a
--- /dev/null
+++ b/github-fast-env.rb
@@ -0,0 +1,161 @@
+#!/usr/bin/env ruby
+
+require "base64"
+require "optparse"
+require "socket"
+
+usage_output = "USAGE:\n    github-fast-env SCRIPT_PATH [options]"
+
+$options = {:verbose => false}
+OptionParser.new do |options|
+	options.banner = usage_output
+	options.on("-v", "--verbose", "Show verbose output") do
+		$options[:verbose] = true
+	end
+end.parse!
+
+if not ARGV or ARGV.empty?
+	$stderr.puts "error: missing argument (script path)\n\n"
+	$stderr.puts usage_output
+	exit 1
+end
+
+if ARGV.length > 1
+	$stderr.puts "error: only one script expected\n\n"
+	$stderr.puts usage_output
+	exit 1
+end
+
+script_path = File.realpath(ARGV[0])
+
+control_socket_path = "/tmp/github-fast-envd.sock"
+
+$control_socket = UNIXSocket.new(control_socket_path)
+
+def log(level, message)
+	if level == "error" or $options[:verbose]
+		$stderr.puts "[github-fast-env] #{level}: #{message}"
+	end
+end
+
+def read_command(control_socket)
+	ready_ios = IO.select([control_socket], [], [], 10)
+
+	if not ready_ios
+		log "error", "timeout while communicating with github-fast-envd"
+		exit 1
+	end
+
+	response = control_socket.readline.strip.split(" ", 2)
+
+	if response.empty?
+		log "error", "malformed response from github-fast-envd"
+		exit 1
+	end
+
+	command = response[0]
+
+	if command == "error"
+		if response.length < 2
+			log "error", "malformed error response from github-fast-envd"
+			exit 1
+		end
+
+		error_message = response[1]
+
+		log "error", "#{error_message}"
+		exit 1
+	end
+
+	if command == "script_error"
+		if response.length < 2
+			log "error", "malformed script error response from github-fast-envd"
+			exit 1
+		end
+
+		error_message = Base64.decode64(response[1])
+
+		$stderr.puts error_message
+		exit 1
+	end
+
+	arguments = response[1].nil? ? [] : response[1].split(" ")
+
+	return command, arguments
+end
+
+log "info", "connected to control socket"
+
+encoded_script_path = Base64.encode64(script_path).delete("\n")
+$control_socket.puts "new v1 #{encoded_script_path}"
+
+pipes = {"stdin" => nil, "stdout" => nil, "stderr" => nil}
+
+while true
+	command, arguments = read_command($control_socket)
+
+	if command == "ready"
+		break
+	end
+
+	if not ["stdin", "stdout", "stderr"].include?(command) or arguments.empty?
+		log "error", "malformed response"
+		exit 1
+	end
+
+	pipe_path = arguments[0]
+
+	log "info", "connecting to #{pipe_path}"
+
+	if command == "stdin"
+		pipes[command] = File::open(pipe_path, "w")
+	else
+		pipes[command] = File::open(pipe_path, "r")
+	end
+
+	pipes[command].sync = true
+
+	log "info", "connected"
+end
+
+log "info", "ready"
+$control_socket.puts "ready"
+
+read_ios = [$control_socket, $stdin, pipes["stdout"], pipes["stderr"]]
+
+while read_ios.include?($control_socket) or read_ios.include?(pipes["stdout"]) or read_ios.include?(pipes["stderr"])
+	log "trace", read_ios.inspect
+
+	ready_read_ios, _, _ = IO.select(read_ios, [], [])
+
+	log "trace", "ready read IOs: #{ready_read_ios.inspect}"
+
+	ready_read_ios.each do |ready_read_io|
+		begin
+			if ready_read_io.equal? $stdin
+				log "trace", "writing to stdin"
+				pipes["stdin"].write ready_read_io.readpartial(4096)
+			elsif ready_read_io.equal? pipes["stdout"]
+				log "trace", "reading from stdout"
+				$stdout.write ready_read_io.readpartial(4096)
+			elsif ready_read_io.equal? pipes["stderr"]
+				log "trace", "reading from stderr"
+				$stderr.write ready_read_io.readpartial(4096)
+			elsif ready_read_io.equal? $control_socket
+				log "trace", "reading from control socket"
+				command, arguments = read_command($control_socket)
+
+				if command != "done"
+					log "error", "malformed response from github-fast-envd"
+				end
+			else
+				log "warn", "received input from unknown stream"
+			end
+		rescue EOFError
+			log "trace", "closing stream"
+			ready_read_io.close
+		end
+	end
+
+	read_ios = read_ios.select {|x| not x.closed?}
+end
diff --git a/github-fast-envd.rb b/github-fast-envd.rb
new file mode 100755
index 0000000..6bd2a27
--- /dev/null
+++ b/github-fast-envd.rb
@@ -0,0 +1,204 @@
+#!/usr/bin/env ruby
+
+require "base64"
+require "socket"
+
+class ClientError < StandardError
+	def initialize(message)
+		super(message)
+	end
+end
+
+class ClientScriptError < StandardError
+	def initialize(source)
+		super(source.message)
+		@source = source
+	end
+
+	def source
+		@source
+	end
+end
+
+control_socket_path = "/tmp/github-fast-envd.sock"
+
+if File.exist?(control_socket_path) and File.socket?(control_socket_path)
+	File.unlink(control_socket_path)
+end
+
+control_server = UNIXServer.new(control_socket_path)
+File.chmod 0700, control_socket_path
+
+#at_exit do
+#	control_server.close
+#end
+
+$stderr.puts "serving control socket"
+
+connection_id = 0
+
+def open_pipe(connection_id, name)
+	pipe_path = "/tmp/github-fast-envd.#{connection_id}.#{name}"
+
+	if File.exist?(pipe_path) and File.pipe?(pipe_path)
+		File.unlink(pipe_path)
+	end
+
+	File.mkfifo(pipe_path, mode = 0600)
+
+	pipe_path
+end
+
+def read_command(control_socket)
+	ready_ios = IO.select([control_socket], [], [], 10)
+
+	if not ready_ios
+		log "error", "timeout while communicating with github-fast-envd"
+		exit 1
+	end
+
+	response = control_socket.readline.strip.split(" ", 2)
+
+	if response.empty?
+		log "error", "malformed response from github-fast-envd"
+		exit 1
+	end
+
+	command = response[0]
+
+	if command == "error"
+		if response.length < 2
+			log "error", "malformed error response from github-fast-envd"
+			exit 1
+		end
+
+		error_message = response[1]
+
+		log "error", "#{error_message}"
+		exit 1
+	end
+
+	arguments = response[1].nil? ? [] : response[1].split(" ")
+
+	return command, arguments
+end
+
+while true
+	control_socket = control_server.accept
+	$stderr.puts "- new connection"
+
+	begin
+		command, arguments = read_command(control_socket)
+
+		if command != "new"
+			raise ClientError.new "unexpected command"
+		end
+
+		if arguments.length != 2
+			raise ClientError.new "malformed command"
+		end
+
+		if arguments[0] != "v1"
+			raise ClientError.new "unsupported protocol version"
+		end
+
+		connection_id += 1
+
+		child_process = fork {
+			original_stdin = $stdin.dup
+			original_stdout = $stdout.dup
+			original_stderr = $stderr.dup
+
+			begin
+				stdin = open_pipe(connection_id, "stdin")
+				control_socket.puts "stdin #{stdin}"
+				stdin = File::open(stdin, "r")
+				stdin.sync = true
+
+				stdout = open_pipe(connection_id, "stdout")
+				control_socket.puts "stdout #{stdout}"
+				stdout = File::open(stdout, "w")
+				stdout.sync = true
+
+				stderr = open_pipe(connection_id, "stderr")
+				control_socket.puts "stderr #{stderr}"
+				stderr = File::open(stderr, "w")
+				stderr.sync = true
+
+				$stderr.puts "  set up pipes"
+				control_socket.puts "ready"
+
+				response = control_socket.readline.strip
+
+				if response != "ready"
+					raise ClientError.new "invalid command"
+					Kernel.exit!
+				end
+
+				script_path = Base64.decode64(arguments[1])
+				$stderr.puts "  executing script " + script_path
+
+				$stdin.reopen(stdin)
+				$stdout.reopen(stdout)
+				$stderr.reopen(stderr)
+
+				begin
+					load script_path, true
+				rescue => error
+					$stdin = original_stdin
+					$stdout = original_stdout
+					$stderr = original_stderr
+
+					raise ClientScriptError.new error
+				end
+			rescue ClientScriptError => error
+				# TODO: Restore pipes to make sure that syntax errors are caught
+				encoded_error_output = Base64.encode64(error.source.full_message).delete("\n")
+				original_stderr.puts "  error executing script, ignoring request"
+				# TODO: if the begin/rescue blog has syntax errors, these go unnoticed
+				begin
+					control_socket.puts "script_error #{encoded_error_output}"
+				rescue
+				end
+			rescue ClientError => error
+				original_stderr.puts "  error communicating with client, ignoring request (#{error})"
+				begin
+					control_socket.puts "error #{error}"
+				rescue
+				end
+			rescue StandardError => error
+				original_stderr.puts "  error, ignoring request (#{error})"
+				begin
+					control_socket.puts "error internal server error"
+				rescue
+				end
+			end
+
+			begin
+				control_socket.puts "done"
+			rescue
+			end
+			control_socket.close
+
+			original_stderr.puts "  finished handling request"
+
+			Kernel.exit!
+		}
+
+		Process.detach(child_process)
+	rescue ClientError => error
+		$stderr.puts "  error communicating with client, ignoring request (#{error})"
+		begin
+			control_socket.puts "error #{error}"
+		rescue
+		end
+	rescue StandardError => error
+		$stderr.puts "  error, ignoring request (#{error})"
+		begin
+			control_socket.puts "error internal server error"
+		rescue
+		end
+	end
+
+	control_socket.close
+end