Add SFTP Server Support (#6753)

* Add SFTP Server Support

Signed-off-by: Mohamed Sekour <mohamed.sekour@exfo.com>

* fix s3 tests and helm lint

Signed-off-by: Mohamed Sekour <mohamed.sekour@exfo.com>

* increase  helm chart version

* adjust version

---------

Signed-off-by: Mohamed Sekour <mohamed.sekour@exfo.com>
Co-authored-by: chrislu <chris.lu@gmail.com>

weed/sftpd/sftp_helpers.go

@@ -0,0 +1,126 @@
+// sftp_helpers.go
+package sftpd
+
+import (
+	"io"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/pkg/sftp"
+	"github.com/seaweedfs/seaweedfs/weed/glog"
+	"github.com/seaweedfs/seaweedfs/weed/util"
+)
+
+// FileInfo implements os.FileInfo.
+type FileInfo struct {
+	name    string
+	size    int64
+	mode    os.FileMode
+	modTime time.Time
+	isDir   bool
+}
+
+func (fi *FileInfo) Name() string       { return fi.name }
+func (fi *FileInfo) Size() int64        { return fi.size }
+func (fi *FileInfo) Mode() os.FileMode  { return fi.mode }
+func (fi *FileInfo) ModTime() time.Time { return fi.modTime }
+func (fi *FileInfo) IsDir() bool        { return fi.isDir }
+func (fi *FileInfo) Sys() interface{}   { return nil }
+
+// bufferReader wraps a byte slice to io.ReaderAt.
+type bufferReader struct {
+	b []byte
+	i int64
+}
+
+func NewBufferReader(b []byte) *bufferReader { return &bufferReader{b: b} }
+
+func (r *bufferReader) Read(p []byte) (int, error) {
+	if r.i >= int64(len(r.b)) {
+		return 0, io.EOF
+	}
+	n := copy(p, r.b[r.i:])
+	r.i += int64(n)
+	return n, nil
+}
+
+func (r *bufferReader) ReadAt(p []byte, off int64) (int, error) {
+	if off >= int64(len(r.b)) {
+		return 0, io.EOF
+	}
+	n := copy(p, r.b[off:])
+	if n < len(p) {
+		return n, io.EOF
+	}
+	return n, nil
+}
+
+// listerat implements sftp.ListerAt.
+type listerat []os.FileInfo
+
+func (l listerat) ListAt(ls []os.FileInfo, offset int64) (int, error) {
+	if offset >= int64(len(l)) {
+		return 0, io.EOF
+	}
+	n := copy(ls, l[offset:])
+	if n < len(ls) {
+		return n, io.EOF
+	}
+	return n, nil
+}
+
+// filerFileWriter buffers writes and flushes on Close.
+type filerFileWriter struct {
+	fs          SftpServer
+	req         *sftp.Request
+	mu          sync.Mutex
+	data        []byte
+	permissions os.FileMode
+	uid         uint32
+	gid         uint32
+	offset      int64
+}
+
+func (w *filerFileWriter) Write(p []byte) (int, error) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	end := w.offset + int64(len(p))
+	if end > int64(len(w.data)) {
+		newBuf := make([]byte, end)
+		copy(newBuf, w.data)
+		w.data = newBuf
+	}
+	n := copy(w.data[w.offset:], p)
+	w.offset += int64(n)
+	return n, nil
+}
+
+func (w *filerFileWriter) WriteAt(p []byte, off int64) (int, error) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	end := int(off) + len(p)
+	if end > len(w.data) {
+		newBuf := make([]byte, end)
+		copy(newBuf, w.data)
+		w.data = newBuf
+	}
+	n := copy(w.data[off:], p)
+	return n, nil
+}
+
+func (w *filerFileWriter) Close() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	dir, _ := util.FullPath(w.req.Filepath).DirAndName()
+
+	// Check permissions based on file metadata and user permissions
+	if err := w.fs.checkFilePermission(dir, "write"); err != nil {
+		glog.Errorf("Permission denied for %s", dir)
+		return err
+	}
+
+	// Call the extracted putFile method on SftpServer
+	return w.fs.putFile(w.req.Filepath, w.data, w.fs.user)
+}