diff options
| -rw-r--r-- | src/crypto/tls/conn.go | 49 |
1 files changed, 24 insertions, 25 deletions
diff --git a/src/crypto/tls/conn.go b/src/crypto/tls/conn.go index 9c662ef8f6..54a4d1a883 100644 --- a/src/crypto/tls/conn.go +++ b/src/crypto/tls/conn.go @@ -800,29 +800,6 @@ func (c *Conn) retryReadRecord(expectChangeCipherSpec bool) error { return c.readRecordOrCCS(expectChangeCipherSpec) } -// atLeastReader reads from R, stopping with EOF once at least N bytes have been -// read. It is different from an io.LimitedReader in that it doesn't cut short -// the last Read call, and in that it considers an early EOF an error. -type atLeastReader struct { - R io.Reader - N int64 -} - -func (r *atLeastReader) Read(p []byte) (int, error) { - if r.N <= 0 { - return 0, io.EOF - } - n, err := r.R.Read(p) - r.N -= int64(n) // won't underflow unless len(p) >= n > 9223372036854775809 - if r.N > 0 && err == io.EOF { - return n, io.ErrUnexpectedEOF - } - if r.N <= 0 && err == nil { - return n, io.EOF - } - return n, err -} - // readFromUntil reads from r into c.rawInput until c.rawInput contains // at least n bytes or else returns an error. func (c *Conn) readFromUntil(r io.Reader, n int) error { @@ -833,9 +810,31 @@ func (c *Conn) readFromUntil(r io.Reader, n int) error { // There might be extra input waiting on the wire. Make a best effort // attempt to fetch it so that it can be used in (*Conn).Read to // "predict" closeNotify alerts. + // TODO(dmo): we use bytes.MinRead here because we used the buffer + // ReadFrom mechanism to avoid allocations, but we've hoisted this + // loop for performance. We really should use our own heuristic here + // for how much to read ahead. c.rawInput.Grow(needs + bytes.MinRead) - _, err := c.rawInput.ReadFrom(&atLeastReader{r, int64(needs)}) - return err + for { + buf := c.rawInput.AvailableBuffer()[:needs+bytes.MinRead] + n, err := r.Read(buf) + // This write is just to update the internal state of the + // rawInput bytes.Buffer. It cannot fail. + c.rawInput.Write(buf[:n]) + needs -= n + if needs <= 0 { + if err == io.EOF { + err = nil + } + return err + } + if err == io.EOF { + return io.ErrUnexpectedEOF + } + if err != nil { + return err + } + } } // sendAlertLocked sends a TLS alert message. |