diff options
Diffstat (limited to 'apps/files_external/lib/Lib/Storage/SFTPReadStream.php')
| -rw-r--r-- | apps/files_external/lib/Lib/Storage/SFTPReadStream.php | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/apps/files_external/lib/Lib/Storage/SFTPReadStream.php b/apps/files_external/lib/Lib/Storage/SFTPReadStream.php new file mode 100644 index 00000000000..7dedbd7035a --- /dev/null +++ b/apps/files_external/lib/Lib/Storage/SFTPReadStream.php @@ -0,0 +1,217 @@ +<?php + +declare(strict_types=1); + +/** + * SPDX-FileCopyrightText: 2020 Nextcloud GmbH and Nextcloud contributors + * SPDX-License-Identifier: AGPL-3.0-or-later + */ +namespace OCA\Files_External\Lib\Storage; + +use Icewind\Streams\File; +use phpseclib\Net\SSH2; + +class SFTPReadStream implements File { + /** @var resource */ + public $context; + + /** @var \phpseclib\Net\SFTP */ + private $sftp; + + /** @var string */ + private $handle; + + /** @var int */ + private $internalPosition = 0; + + /** @var int */ + private $readPosition = 0; + + /** @var bool */ + private $eof = false; + + private $buffer = ''; + private bool $pendingRead = false; + private int $size = 0; + + public static function register($protocol = 'sftpread') { + if (in_array($protocol, stream_get_wrappers(), true)) { + return false; + } + return stream_wrapper_register($protocol, get_called_class()); + } + + /** + * Load the source from the stream context and return the context options + * + * @throws \BadMethodCallException + */ + protected function loadContext(string $name) { + $context = stream_context_get_options($this->context); + if (isset($context[$name])) { + $context = $context[$name]; + } else { + throw new \BadMethodCallException('Invalid context, "' . $name . '" options not set'); + } + if (isset($context['session']) and $context['session'] instanceof \phpseclib\Net\SFTP) { + $this->sftp = $context['session']; + } else { + throw new \BadMethodCallException('Invalid context, session not set'); + } + if (isset($context['size'])) { + $this->size = $context['size']; + } + return $context; + } + + public function stream_open($path, $mode, $options, &$opened_path) { + [, $path] = explode('://', $path); + $path = '/' . ltrim($path); + $path = str_replace('//', '/', $path); + + $this->loadContext('sftp'); + + if (!($this->sftp->bitmap & SSH2::MASK_LOGIN)) { + return false; + } + + $remote_file = $this->sftp->_realpath($path); + if ($remote_file === false) { + return false; + } + + $packet = pack('Na*N2', strlen($remote_file), $remote_file, NET_SFTP_OPEN_READ, 0); + if (!$this->sftp->_send_sftp_packet(NET_SFTP_OPEN, $packet)) { + return false; + } + + $response = $this->sftp->_get_sftp_packet(); + switch ($this->sftp->packet_type) { + case NET_SFTP_HANDLE: + $this->handle = substr($response, 4); + break; + case NET_SFTP_STATUS: // presumably SSH_FX_NO_SUCH_FILE or SSH_FX_PERMISSION_DENIED + $this->sftp->_logError($response); + return false; + default: + user_error('Expected SSH_FXP_HANDLE or SSH_FXP_STATUS'); + return false; + } + + $this->request_chunk(256 * 1024); + + return true; + } + + public function stream_seek($offset, $whence = SEEK_SET) { + switch ($whence) { + case SEEK_SET: + $this->seekTo($offset); + break; + case SEEK_CUR: + $this->seekTo($this->readPosition + $offset); + break; + case SEEK_END: + $this->seekTo($this->size + $offset); + break; + } + return true; + } + + private function seekTo(int $offset): void { + $this->internalPosition = $offset; + $this->readPosition = $offset; + $this->buffer = ''; + $this->request_chunk(256 * 1024); + } + + public function stream_tell() { + return $this->readPosition; + } + + public function stream_read($count) { + if (!$this->eof && strlen($this->buffer) < $count) { + $chunk = $this->read_chunk(); + $this->buffer .= $chunk; + if (!$this->eof) { + $this->request_chunk(256 * 1024); + } + } + + $data = substr($this->buffer, 0, $count); + $this->buffer = substr($this->buffer, $count); + $this->readPosition += strlen($data); + + return $data; + } + + private function request_chunk(int $size) { + if ($this->pendingRead) { + $this->sftp->_get_sftp_packet(); + } + + $packet = pack('Na*N3', strlen($this->handle), $this->handle, $this->internalPosition / 4294967296, $this->internalPosition, $size); + $this->pendingRead = true; + return $this->sftp->_send_sftp_packet(NET_SFTP_READ, $packet); + } + + private function read_chunk() { + $this->pendingRead = false; + $response = $this->sftp->_get_sftp_packet(); + + switch ($this->sftp->packet_type) { + case NET_SFTP_DATA: + $temp = substr($response, 4); + $len = strlen($temp); + $this->internalPosition += $len; + return $temp; + case NET_SFTP_STATUS: + [1 => $status] = unpack('N', substr($response, 0, 4)); + if ($status == NET_SFTP_STATUS_EOF) { + $this->eof = true; + } + return ''; + default: + return ''; + } + } + + public function stream_write($data) { + return false; + } + + public function stream_set_option($option, $arg1, $arg2) { + return false; + } + + public function stream_truncate($size) { + return false; + } + + public function stream_stat() { + return false; + } + + public function stream_lock($operation) { + return false; + } + + public function stream_flush() { + return false; + } + + public function stream_eof() { + return $this->eof; + } + + public function stream_close() { + // we still have a read request incoming that needs to be handled before we can close + if ($this->pendingRead) { + $this->sftp->_get_sftp_packet(); + } + if (!$this->sftp->_close_handle($this->handle)) { + return false; + } + return true; + } +} |