protected void doRealPath()

in sshd-sftp/src/main/java/org/apache/sshd/sftp/server/AbstractSftpSubsystemHelper.java [1420:1517]
78 lines of code
17 McCabe index (conditional complexity)

    protected void doRealPath(Buffer buffer, int id) throws IOException {
        // do things here.
        String path = buffer.getString();
        boolean debugEnabled = log.isDebugEnabled();
        ServerSession session = getServerSession();
        if (debugEnabled) {
            log.debug("doRealPath({})[id={}] SSH_FXP_REALPATH (path={})", session, id, path);
        }
        path = GenericUtils.trimToEmpty(path);
        if (GenericUtils.isEmpty(path)) {
            path = ".";
        }

        Map<String, ?> attrs = Collections.emptyMap();
        Map.Entry<Path, Boolean> result;
        try {
            int version = getVersion();
            if (version < SftpConstants.SFTP_V6) {
                /*
                 * See http://www.openssh.com/txt/draft-ietf-secsh-filexfer-02.txt:
                 *
                 * The SSH_FXP_REALPATH request can be used to have the server canonicalize any given path name to an
                 * absolute path.
                 *
                 * See also SSHD-294
                 */
                Path p = resolveFile(path);
                LinkOption[] options = getPathResolutionLinkOption(SftpConstants.SSH_FXP_REALPATH, "", p);
                result = doRealPathV345(id, path, p, options);
            } else {
                /*
                 * See https://tools.ietf.org/html/draft-ietf-secsh-filexfer-13#section-8.9
                 *
                 * This field is optional, and if it is not present in the packet, it is assumed to be
                 * SSH_FXP_REALPATH_NO_CHECK.
                 */
                int control = SftpConstants.SSH_FXP_REALPATH_NO_CHECK;
                if (buffer.available() > 0) {
                    control = buffer.getUByte();
                    if (debugEnabled) {
                        log.debug("doRealPath({}) - control=0x{} for path={}",
                                session, Integer.toHexString(control), path);
                    }
                }

                Collection<String> extraPaths = new LinkedList<>();
                while (buffer.available() > 0) {
                    extraPaths.add(buffer.getString());
                }

                Path p = resolveFile(path);
                LinkOption[] options = getPathResolutionLinkOption(SftpConstants.SSH_FXP_REALPATH, "", p);
                result = doRealPathV6(id, path, extraPaths, p, options);

                p = result.getKey();
                Boolean status = result.getValue();
                switch (control) {
                    case SftpConstants.SSH_FXP_REALPATH_STAT_IF:
                        if (status == null) {
                            attrs = handleUnknownStatusFileAttributes(
                                    p, SftpConstants.SSH_FILEXFER_ATTR_ALL, options);
                        } else if (status) {
                            try {
                                attrs = getAttributes(p, options);
                            } catch (IOException e) {
                                debug("doRealPath({}) - failed ({}) to retrieve attributes of {}: {}",
                                        session, e.getClass().getSimpleName(), p, e.getMessage(), e);
                            }
                        } else {
                            if (debugEnabled) {
                                log.debug("doRealPath({}) - dummy attributes for non-existing file: {}", session, p);
                            }
                        }
                        break;
                    case SftpConstants.SSH_FXP_REALPATH_STAT_ALWAYS:
                        if (status == null) {
                            attrs = handleUnknownStatusFileAttributes(
                                    p, SftpConstants.SSH_FILEXFER_ATTR_ALL, options);
                        } else if (status) {
                            attrs = getAttributes(p, options);
                        } else {
                            throw new NoSuchFileException(p.toString(), p.toString(), "Real path N/A for target");
                        }
                        break;
                    case SftpConstants.SSH_FXP_REALPATH_NO_CHECK:
                        break;
                    default:
                        log.warn("doRealPath({}) unknown control value 0x{} for path={}",
                                session, Integer.toHexString(control), p);
                }
            }
        } catch (IOException | RuntimeException e) {
            sendStatus(prepareReply(buffer), id, e, SftpConstants.SSH_FXP_REALPATH, path);
            return;
        }

        sendPath(prepareReply(buffer), id, result.getKey(), attrs);
    }