diff options
Diffstat (limited to 'pkg/sentry/fs/tty/line_discipline.go')
| -rw-r--r-- | pkg/sentry/fs/tty/line_discipline.go | 46 |
1 files changed, 26 insertions, 20 deletions
diff --git a/pkg/sentry/fs/tty/line_discipline.go b/pkg/sentry/fs/tty/line_discipline.go index 484366f85..31b6344f2 100644 --- a/pkg/sentry/fs/tty/line_discipline.go +++ b/pkg/sentry/fs/tty/line_discipline.go @@ -140,9 +140,9 @@ func (l *lineDiscipline) setTermios(ctx context.Context, io usermem.IO, args arc // buffer to its read buffer. Anything already in the read buffer is // now readable. if oldCanonEnabled && !l.termios.LEnabled(linux.ICANON) { - if n := l.inQueue.pushWaitBuf(l); n > 0 { - l.slaveWaiter.Notify(waiter.EventIn) - } + l.inQueue.pushWaitBuf(l) + l.inQueue.readable = true + l.slaveWaiter.Notify(waiter.EventIn) } return 0, err @@ -263,7 +263,7 @@ type outputQueueTransformer struct{} // transform does output processing for one end of the pty. See // drivers/tty/n_tty.c:do_output_char for an analogous kernel function. // -// Precondition: +// Preconditions: // * l.termiosMu must be held for reading. // * q.mu must be held. func (*outputQueueTransformer) transform(l *lineDiscipline, q *queue, buf []byte) int { @@ -271,11 +271,11 @@ func (*outputQueueTransformer) transform(l *lineDiscipline, q *queue, buf []byte // master termios never has ICANON set. if !l.termios.OEnabled(linux.OPOST) { - n, _ := q.readBuf.Write(buf) - if q.readBuf.Len() > 0 { + q.readBuf = append(q.readBuf, buf...) + if len(q.readBuf) > 0 { q.readable = true } - return n + return len(buf) } var ret int @@ -289,7 +289,7 @@ func (*outputQueueTransformer) transform(l *lineDiscipline, q *queue, buf []byte l.column = 0 } if l.termios.OEnabled(linux.ONLCR) { - q.readBuf.Write([]byte{'\r', '\n'}) + q.readBuf = append(q.readBuf, '\r', '\n') continue } case '\r': @@ -308,7 +308,7 @@ func (*outputQueueTransformer) transform(l *lineDiscipline, q *queue, buf []byte spaces := spacesPerTab - l.column%spacesPerTab if l.termios.OutputFlags&linux.TABDLY == linux.XTABS { l.column += spaces - q.readBuf.Write(bytes.Repeat([]byte{' '}, spacesPerTab)) + q.readBuf = append(q.readBuf, bytes.Repeat([]byte{' '}, spacesPerTab)...) continue } l.column += spaces @@ -319,9 +319,12 @@ func (*outputQueueTransformer) transform(l *lineDiscipline, q *queue, buf []byte default: l.column++ } - q.readBuf.WriteRune(c) + // The compiler optimizes this by growing readBuf without + // creating the intermediate slice. + q.readBuf = append(q.readBuf, make([]byte, size)...) + utf8.EncodeRune(q.readBuf[len(q.readBuf)-size:], c) } - if q.readBuf.Len() > 0 { + if len(q.readBuf) > 0 { q.readable = true } return ret @@ -338,7 +341,7 @@ type inputQueueTransformer struct{} // drivers/tty/n_tty.c:n_tty_receive_char_special for an analogous kernel // function. // -// Precondition: +// Preconditions: // * l.termiosMu must be held for reading. // * q.mu must be held. func (*inputQueueTransformer) transform(l *lineDiscipline, q *queue, buf []byte) int { @@ -354,7 +357,7 @@ func (*inputQueueTransformer) transform(l *lineDiscipline, q *queue, buf []byte) } var ret int - for len(buf) > 0 && q.readBuf.Len() < canonMaxBytes { + for len(buf) > 0 && len(q.readBuf) < canonMaxBytes { c, size := l.peekRune(buf) switch c { case '\r': @@ -381,7 +384,7 @@ func (*inputQueueTransformer) transform(l *lineDiscipline, q *queue, buf []byte) } // Stop if the buffer would be overfilled. - if q.readBuf.Len()+size > maxBytes { + if len(q.readBuf)+size > maxBytes { break } cBytes := buf[:size] @@ -394,12 +397,15 @@ func (*inputQueueTransformer) transform(l *lineDiscipline, q *queue, buf []byte) break } - q.readBuf.WriteRune(c) + // The compiler optimizes this by growing readBuf without + // creating the intermediate slice. + q.readBuf = append(q.readBuf, make([]byte, size)...) + utf8.EncodeRune(q.readBuf[len(q.readBuf)-size:], c) + // Anything written to the readBuf will have to be echoed. if l.termios.LEnabled(linux.ECHO) { - if l.outQueue.writeBytes(cBytes, l) > 0 { - l.masterWaiter.Notify(waiter.EventIn) - } + l.outQueue.writeBytes(cBytes, l) + l.masterWaiter.Notify(waiter.EventIn) } // If we finish a line, make it available for reading. @@ -410,7 +416,7 @@ func (*inputQueueTransformer) transform(l *lineDiscipline, q *queue, buf []byte) } // In noncanonical mode, everything is readable. - if !l.termios.LEnabled(linux.ICANON) && q.readBuf.Len() > 0 { + if !l.termios.LEnabled(linux.ICANON) && len(q.readBuf) > 0 { q.readable = true } @@ -425,7 +431,7 @@ func (*inputQueueTransformer) transform(l *lineDiscipline, q *queue, buf []byte) // * l.termiosMu must be held for reading. // * q.mu must be held. func (l *lineDiscipline) shouldDiscard(q *queue, c rune) bool { - return l.termios.LEnabled(linux.ICANON) && q.readBuf.Len()+utf8.RuneLen(c) >= canonMaxBytes && !l.termios.IsTerminating(c) + return l.termios.LEnabled(linux.ICANON) && len(q.readBuf)+utf8.RuneLen(c) >= canonMaxBytes && !l.termios.IsTerminating(c) } // peekRune returns the first rune from the byte array depending on whether |