1 files changed, 270 insertions, 0 deletions
diff --git a/src/net/http/fcgi/fcgi.go b/src/net/http/fcgi/fcgi.go
new file mode 100644
index 0000000..fb822f8
--- /dev/null
+++ b/src/net/http/fcgi/fcgi.go
@@ -0,0 +1,270 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package fcgi implements the FastCGI protocol.
+//
+// See https://fast-cgi.github.io/ for an unofficial mirror of the
+// original documentation.
+//
+// Currently only the responder role is supported.
+package fcgi
+
+// This file defines the raw protocol and some utilities used by the child and
+// the host.
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"io"
+	"sync"
+)
+
+// recType is a record type, as defined by
+// https://web.archive.org/web/20150420080736/http://www.fastcgi.com/drupal/node/6?q=node/22#S8
+type recType uint8
+
+const (
+	typeBeginRequest    recType = 1
+	typeAbortRequest    recType = 2
+	typeEndRequest      recType = 3
+	typeParams          recType = 4
+	typeStdin           recType = 5
+	typeStdout          recType = 6
+	typeStderr          recType = 7
+	typeData            recType = 8
+	typeGetValues       recType = 9
+	typeGetValuesResult recType = 10
+	typeUnknownType     recType = 11
+)
+
+// keep the connection between web-server and responder open after request
+const flagKeepConn = 1
+
+const (
+	maxWrite = 65535 // maximum record body
+	maxPad   = 255
+)
+
+const (
+	roleResponder = iota + 1 // only Responders are implemented.
+	roleAuthorizer
+	roleFilter
+)
+
+const (
+	statusRequestComplete = iota
+	statusCantMultiplex
+	statusOverloaded
+	statusUnknownRole
+)
+
+type header struct {
+	Version       uint8
+	Type          recType
+	Id            uint16
+	ContentLength uint16
+	PaddingLength uint8
+	Reserved      uint8
+}
+
+type beginRequest struct {
+	role     uint16
+	flags    uint8
+	reserved [5]uint8
+}
+
+func (br *beginRequest) read(content []byte) error {
+	if len(content) != 8 {
+		return errors.New("fcgi: invalid begin request record")
+	}
+	br.role = binary.BigEndian.Uint16(content)
+	br.flags = content[2]
+	return nil
+}
+
+// for padding so we don't have to allocate all the time
+// not synchronized because we don't care what the contents are
+var pad [maxPad]byte
+
+func (h *header) init(recType recType, reqId uint16, contentLength int) {
+	h.Version = 1
+	h.Type = recType
+	h.Id = reqId
+	h.ContentLength = uint16(contentLength)
+	h.PaddingLength = uint8(-contentLength & 7)
+}
+
+// conn sends records over rwc
+type conn struct {
+	mutex sync.Mutex
+	rwc   io.ReadWriteCloser
+
+	// to avoid allocations
+	buf bytes.Buffer
+	h   header
+}
+
+func newConn(rwc io.ReadWriteCloser) *conn {
+	return &conn{rwc: rwc}
+}
+
+func (c *conn) Close() error {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+	return c.rwc.Close()
+}
+
+type record struct {
+	h   header
+	buf [maxWrite + maxPad]byte
+}
+
+func (rec *record) read(r io.Reader) (err error) {
+	if err = binary.Read(r, binary.BigEndian, &rec.h); err != nil {
+		return err
+	}
+	if rec.h.Version != 1 {
+		return errors.New("fcgi: invalid header version")
+	}
+	n := int(rec.h.ContentLength) + int(rec.h.PaddingLength)
+	if _, err = io.ReadFull(r, rec.buf[:n]); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (r *record) content() []byte {
+	return r.buf[:r.h.ContentLength]
+}
+
+// writeRecord writes and sends a single record.
+func (c *conn) writeRecord(recType recType, reqId uint16, b []byte) error {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+	c.buf.Reset()
+	c.h.init(recType, reqId, len(b))
+	if err := binary.Write(&c.buf, binary.BigEndian, c.h); err != nil {
+		return err
+	}
+	if _, err := c.buf.Write(b); err != nil {
+		return err
+	}
+	if _, err := c.buf.Write(pad[:c.h.PaddingLength]); err != nil {
+		return err
+	}
+	_, err := c.rwc.Write(c.buf.Bytes())
+	return err
+}
+
+func (c *conn) writeEndRequest(reqId uint16, appStatus int, protocolStatus uint8) error {
+	b := make([]byte, 8)
+	binary.BigEndian.PutUint32(b, uint32(appStatus))
+	b[4] = protocolStatus
+	return c.writeRecord(typeEndRequest, reqId, b)
+}
+
+func (c *conn) writePairs(recType recType, reqId uint16, pairs map[string]string) error {
+	w := newWriter(c, recType, reqId)
+	b := make([]byte, 8)
+	for k, v := range pairs {
+		n := encodeSize(b, uint32(len(k)))
+		n += encodeSize(b[n:], uint32(len(v)))
+		if _, err := w.Write(b[:n]); err != nil {
+			return err
+		}
+		if _, err := w.WriteString(k); err != nil {
+			return err
+		}
+		if _, err := w.WriteString(v); err != nil {
+			return err
+		}
+	}
+	w.Close()
+	return nil
+}
+
+func readSize(s []byte) (uint32, int) {
+	if len(s) == 0 {
+		return 0, 0
+	}
+	size, n := uint32(s[0]), 1
+	if size&(1<<7) != 0 {
+		if len(s) < 4 {
+			return 0, 0
+		}
+		n = 4
+		size = binary.BigEndian.Uint32(s)
+		size &^= 1 << 31
+	}
+	return size, n
+}
+
+func readString(s []byte, size uint32) string {
+	if size > uint32(len(s)) {
+		return ""
+	}
+	return string(s[:size])
+}
+
+func encodeSize(b []byte, size uint32) int {
+	if size > 127 {
+		size |= 1 << 31
+		binary.BigEndian.PutUint32(b, size)
+		return 4
+	}
+	b[0] = byte(size)
+	return 1
+}
+
+// bufWriter encapsulates bufio.Writer but also closes the underlying stream when
+// Closed.
+type bufWriter struct {
+	closer io.Closer
+	*bufio.Writer
+}
+
+func (w *bufWriter) Close() error {
+	if err := w.Writer.Flush(); err != nil {
+		w.closer.Close()
+		return err
+	}
+	return w.closer.Close()
+}
+
+func newWriter(c *conn, recType recType, reqId uint16) *bufWriter {
+	s := &streamWriter{c: c, recType: recType, reqId: reqId}
+	w := bufio.NewWriterSize(s, maxWrite)
+	return &bufWriter{s, w}
+}
+
+// streamWriter abstracts out the separation of a stream into discrete records.
+// It only writes maxWrite bytes at a time.
+type streamWriter struct {
+	c       *conn
+	recType recType
+	reqId   uint16
+}
+
+func (w *streamWriter) Write(p []byte) (int, error) {
+	nn := 0
+	for len(p) > 0 {
+		n := len(p)
+		if n > maxWrite {
+			n = maxWrite
+		}
+		if err := w.c.writeRecord(w.recType, w.reqId, p[:n]); err != nil {
+			return nn, err
+		}
+		nn += n
+		p = p[n:]
+	}
+	return nn, nil
+}
+
+func (w *streamWriter) Close() error {
+	// send empty record to close the stream
+	return w.c.writeRecord(w.recType, w.reqId, nil)
+}