added sftp client implementation

vendor/github.com/pkg/sftp/server_statvfs_impl.go

@@ -0,0 +1,29 @@
+// +build darwin linux
+
+// fill in statvfs structure with OS specific values
+// Statfs_t is different per-kernel, and only exists on some unixes (not Solaris for instance)
+
+package sftp
+
+import (
+	"syscall"
+)
+
+func (p *sshFxpExtendedPacketStatVFS) respond(svr *Server) responsePacket {
+	retPkt, err := getStatVFSForPath(p.Path)
+	if err != nil {
+		return statusFromError(p.ID, err)
+	}
+	retPkt.ID = p.ID
+
+	return retPkt
+}
+
+func getStatVFSForPath(name string) (*StatVFS, error) {
+	var stat syscall.Statfs_t
+	if err := syscall.Statfs(name, &stat); err != nil {
+		return nil, err
+	}
+
+	return statvfsFromStatfst(&stat)
+}