Fix some issues found by lint

internal/anonssh/anonssh.go

@@ -48,6 +48,8 @@ type session struct {
 }
 
 func (s *session) request(ctx context.Context, req *ssh.Request) error {
+	_ = ctx // FIXME: not yet used
+
 	switch req.Type {
 
 	case "env":

internal/maincmd/maincmd.go

@@ -34,7 +34,7 @@ func Main(ctx context.Context, args []string, stdin io.Reader, stdout io.Writer,
 	opts, opt := rsyncd.NewGetOpt()
 	remaining, err := opt.Parse(args[1:])
 	if opt.Called("help") {
-		fmt.Fprintf(stderr, opt.Help())
+		fmt.Fprint(stderr, opt.Help())
 		os.Exit(1)
 	}
 	if err != nil {

internal/receivermaincmd/generator.go

@@ -86,7 +86,7 @@ func (rt *recvTransfer) setPerms(f *file) error {
 		}
 	}
 
-	st, err = rt.setUid(f, local, st)
+	_, err = rt.setUid(f, local, st)
 	if err != nil {
 		return err
 	}
@@ -260,13 +260,13 @@ func (rt *recvTransfer) recvGenerator(idx int, f *file) error {
 }
 
 // rsync/generator.c:generate_and_send_sums
-func (rt *recvTransfer) generateAndSendSums(in *os.File, len int64) error {
-	sh := rsynccommon.SumSizesSqroot(len)
+func (rt *recvTransfer) generateAndSendSums(in *os.File, fileLen int64) error {
+	sh := rsynccommon.SumSizesSqroot(fileLen)
 	if err := sh.WriteTo(rt.conn); err != nil {
 		return err
 	}
 	buf := make([]byte, int(sh.BlockLength))
-	remaining := len
+	remaining := fileLen
 	for i := int32(0); i < sh.ChecksumCount; i++ {
 		n1 := int64(sh.BlockLength)
 		if n1 > remaining {

internal/receivermaincmd/receiver.go

@@ -121,11 +121,11 @@ func (rt *recvTransfer) receiveData(f *file, localFile *os.File) error {
 		}
 		token = -(token + 1)
 		offset2 := int64(token) * int64(sh.BlockLength)
-		len := sh.BlockLength
+		dataLen := sh.BlockLength
 		if token == sh.ChecksumCount-1 && sh.RemainderLength != 0 {
-			len = sh.RemainderLength
+			dataLen = sh.RemainderLength
 		}
-		data = make([]byte, len)
+		data = make([]byte, dataLen)
 		if _, err := localFile.ReadAt(data, offset2); err != nil {
 			return err
 		}

internal/receivermaincmd/receivermaincmd.go

@@ -195,7 +195,7 @@ func rsyncMain(osenv osenv, opts *Opts, sources []string, dest string) (*Stats,
 				user = machine[:idx]
 				machine = machine[idx+1:]
 			}
-			rc, wc, err := doCmd(osenv, opts, machine, user, path, daemonConnection)
+			rc, wc, err := doCmd(opts, machine, user, path, daemonConnection)
 			if err != nil {
 				return nil, err
 			}
@@ -236,7 +236,7 @@ func (prw *readWriter) Write(p []byte) (n int, err error) {
 }
 
 // rsync/main.c:do_cmd
-func doCmd(osenv osenv, opts *Opts, machine, user, path string, daemonConnection int) (io.ReadCloser, io.WriteCloser, error) {
+func doCmd(opts *Opts, machine, user, path string, daemonConnection int) (io.ReadCloser, io.WriteCloser, error) {
 	cmd := opts.ShellCommand
 	if cmd == "" {
 		cmd = "ssh"

internal/rsyncchecksum/rsyncchecksum.go

@@ -23,12 +23,12 @@ func signExtend(b byte) uint32 {
 }
 
 func Checksum1(buf []byte) uint32 {
-	len := len(buf)
+	bufLen := len(buf)
 	var s1, s2 uint32
 	var i int
 
-	if len > 4 {
-		for i = 0; i < (len - 4); i += 4 {
+	if bufLen > 4 {
+		for i = 0; i < (bufLen - 4); i += 4 {
 			s2 += 4*(s1+signExtend(buf[i])) +
 				3*signExtend(buf[i+1]) +
 				2*signExtend(buf[i+2]) +
@@ -39,7 +39,7 @@ func Checksum1(buf []byte) uint32 {
 				signExtend(buf[i+3])
 		}
 	}
-	for ; i < len; i++ {
+	for ; i < bufLen; i++ {
 		s1 += signExtend(buf[i])
 		s2 += s1
 	}

internal/rsynccommon/rsynccommon.go

@@ -11,15 +11,15 @@ import (
 const blockSize = 700 // rsync/rsync.h
 
 // Corresponds to rsync/generator.c:sum_sizes_sqroot
-func SumSizesSqroot(len int64) rsync.SumHead {
+func SumSizesSqroot(contentLen int64) rsync.SumHead {
 	// * The block size is a rounded square root of file length.
 
 	// 	The block size algorithm plays a crucial role in the protocol efficiency. In general, the block size is the rounded square root of the total file size. The minimum block size, however, is 700 B. Otherwise, the square root computation is simply sqrt(3) followed by ceil(3)
 
 	// For reasons unknown, the square root result is rounded up to the nearest multiple of eight.
 
 	// TODO: round this
-	blockLength := int32(math.Sqrt(float64(len)))
+	blockLength := int32(math.Sqrt(float64(contentLen)))
 	if blockLength < blockSize {
 		blockLength = blockSize
 	}
@@ -32,8 +32,8 @@ func SumSizesSqroot(len int64) rsync.SumHead {
 	const checksumLength = 16 // TODO?
 
 	return rsync.SumHead{
-		ChecksumCount:   int32((len + (int64(blockLength) - 1)) / int64(blockLength)),
-		RemainderLength: int32(len % int64(blockLength)),
+		ChecksumCount:   int32((contentLen + (int64(blockLength) - 1)) / int64(blockLength)),
+		RemainderLength: int32(contentLen % int64(blockLength)),
 		BlockLength:     blockLength,
 		ChecksumLength:  checksumLength,
 	}

internal/rsyncd/flist.go

@@ -14,7 +14,7 @@ import (
 )
 
 // rsync/flist.c:send_file_list
-func (st *sendTransfer) sendFileList(c *rsyncwire.Conn, mod config.Module, opts *Opts, paths []string) (*fileList, error) {
+func (st *sendTransfer) sendFileList(mod config.Module, opts *Opts, paths []string) (*fileList, error) {
 	var fileList fileList
 	fec := &rsyncwire.Buffer{}
 

internal/rsyncd/match.go

@@ -243,12 +243,14 @@ func (st *sendTransfer) matched(h hash.Hash, f *os.File, head rsync.SumHead, off
 			offset, st.lastMatch, i, head.Sums[i].Len, n)
 	}
 
+	/* FIXME: this is not used
 	l := int64(0)
 	if !transmitAccumulated {
 		l = head.Sums[i].Len
 	}
+	*/
 
-	if err := st.sendToken(f, i, st.lastMatch, n, l); err != nil {
+	if err := st.sendToken(f, i, st.lastMatch, n); err != nil {
 		return fmt.Errorf("sendToken: %v", err)
 	}
 	// TODO: data_transfer += n;

internal/rsyncd/rsyncd.go

@@ -69,15 +69,6 @@ type fileList struct {
 	files     []file
 }
 
-// rsync/rsync.h:struct sum_buf
-type sumBuf struct {
-	offset int64
-	len    int64
-	index  int32
-	sum1   uint32
-	sum2   [16]byte
-}
-
 // rsync/rsync.h defines chunkSize as 32 * 1024, but increasing it to 256K
 // increases throughput with “tridge” rsync as client by 50 Mbit/s.
 const chunkSize = 256 * 1024
@@ -332,7 +323,7 @@ func (s *Server) HandleConn(module config.Module, rd io.Reader, crd *countingRea
 	// https://github.com/kristapsdz/openrsync/blob/master/rsync.5
 
 	// send file list
-	fileList, err := st.sendFileList(c, module, opts, paths)
+	fileList, err := st.sendFileList(module, opts, paths)
 	if err != nil {
 		return err
 	}

internal/rsyncd/token.go

@@ -36,13 +36,13 @@ func (st *sendTransfer) simpleSendToken(f *os.File, token int32, offset int64, n
 		}
 	}
 	if token != -2 {
-		return st.conn.WriteInt32(-(int32(token) + 1))
+		return st.conn.WriteInt32(-(token + 1))
 	}
 	return nil
 }
 
 // rsync/token.c:send_token
-func (st *sendTransfer) sendToken(f *os.File, i int32, offset int64, n int64, toklen int64) error {
+func (st *sendTransfer) sendToken(f *os.File, i int32, offset int64, n int64) error {
 	// TODO(compression): send deflated token
 	return st.simpleSendToken(f, i, offset, n)
 }

types.go

@@ -2,6 +2,7 @@ package rsync
 
 import "github.com/gokrazy/rsync/internal/rsyncwire"
 
+// rsync/rsync.h:struct sum_buf
 type SumBuf struct {
 	Offset int64
 	Len    int64