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http/spdy: fix data race in header decompression.

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flate's reader greedily reads from the shared io.Reader in Framer. This leads to a data race on Framer.r. Fix this by providing a corkedReader to zlib.NewReaderDict(). We uncork the reader and allow it to read the number of bytes in the compressed payload.

Fixes #1884.

R=bradfitz, rsc, go.peter.90
CC=golang-dev
https://golang.org/cl/4530089
This commit is contained in:
William Chan 2011-05-31 14:05:35 -07:00 committed by Brad Fitzpatrick
parent f4349f7368
commit fecab40586
2 changed files with 26 additions and 17 deletions
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31
src/pkg/http/spdy/framer.go
View File

@ -44,6 +44,24 @@ func (e FramerError) String() string {
return "Error(" + strconv.Itoa(int(e)) + ")"
}
type corkedReader struct {
r io.Reader
ch chan int
n int
}
func (cr *corkedReader) Read(p []byte) (int, os.Error) {
if cr.n == 0 {
cr.n = <-cr.ch
}
if len(p) > cr.n {
p = p[:cr.n]
}
n, err := cr.r.Read(p)
cr.n -= n
return n, err
}
// Framer handles serializing/deserializing SPDY frames, including compressing/
// decompressing payloads.
type Framer struct {
@ -52,6 +70,7 @@ type Framer struct {
headerBuf *bytes.Buffer
headerCompressor *zlib.Writer
r io.Reader
headerReader corkedReader
headerDecompressor io.ReadCloser
}
@ -74,11 +93,13 @@ func NewFramer(w io.Writer, r io.Reader) (*Framer, os.Error) {
return framer, nil
}
func (f *Framer) initHeaderDecompression() os.Error {
func (f *Framer) uncorkHeaderDecompressor(payloadSize int) os.Error {
if f.headerDecompressor != nil {
f.headerReader.ch <- payloadSize
return nil
}
decompressor, err := zlib.NewReaderDict(f.r, []byte(HeaderDictionary))
f.headerReader = corkedReader{r: f.r, ch: make(chan int, 1), n: payloadSize}
decompressor, err := zlib.NewReaderDict(&f.headerReader, []byte(HeaderDictionary))
if err != nil {
return err
}
@ -171,7 +192,7 @@ func (f *Framer) readSynStreamFrame(h ControlFrameHeader, frame *SynStreamFrame)
reader := f.r
if !f.headerCompressionDisabled {
f.initHeaderDecompression()
f.uncorkHeaderDecompressor(int(h.length - 10))
reader = f.headerDecompressor
}
@ -194,7 +215,7 @@ func (f *Framer) readSynReplyFrame(h ControlFrameHeader, frame *SynReplyFrame) o
}
reader := f.r
if !f.headerCompressionDisabled {
f.initHeaderDecompression()
f.uncorkHeaderDecompressor(int(h.length - 6))
reader = f.headerDecompressor
}
frame.Headers, err = parseHeaderValueBlock(reader)
@ -216,7 +237,7 @@ func (f *Framer) readHeadersFrame(h ControlFrameHeader, frame *HeadersFrame) os.
}
reader := f.r
if !f.headerCompressionDisabled {
f.initHeaderDecompression()
f.uncorkHeaderDecompressor(int(h.length - 6))
reader = f.headerDecompressor
}
frame.Headers, err = parseHeaderValueBlock(reader)

12
src/pkg/http/spdy/framer_test.go
View File

@ -371,12 +371,6 @@ func TestCreateParseDataFrame(t *testing.T) {
}
func TestCompressionContextAcrossFrames(t *testing.T) {
{
// TODO(willchan,bradfitz): test is temporarily disabled
t.Logf("test temporarily disabled; http://code.google.com/p/go/issues/detail?id=1884")
return
}
buffer := new(bytes.Buffer)
framer, err := NewFramer(buffer, buffer)
if err != nil {
@ -430,12 +424,6 @@ func TestCompressionContextAcrossFrames(t *testing.T) {
}
func TestMultipleSPDYFrames(t *testing.T) {
{
// TODO(willchan,bradfitz): test is temporarily disabled
t.Logf("test temporarily disabled; http://code.google.com/p/go/issues/detail?id=1884")
return
}
// Initialize the framers.
pr1, pw1 := io.Pipe()
pr2, pw2 := io.Pipe()