nextcloud/apps/files_external/lib/Lib/Storage/SFTPReadStream.php

204 lines
4.9 KiB
PHP

<?php
declare(strict_types=1);
/**
* @copyright Copyright (c) 2020 Robin Appelman <robin@icewind.nl>
*
* @author Robin Appelman <robin@icewind.nl>
*
* @license GNU AGPL version 3 or any later version
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
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 resource */
private $handle;
/** @var int */
private $internalPosition = 0;
/** @var int */
private $readPosition = 0;
/** @var bool */
private $eof = false;
private $buffer = '';
public static function register($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
*
* @param string $name
* @return array
* @throws \BadMethodCallException
*/
protected function loadContext($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');
}
return $context;
}
public function stream_open($path, $mode, $options, &$opened_path) {
[, $path] = explode('://', $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) {
return false;
}
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, $count);
if ($this->buffer === false) {
$this->buffer = '';
}
$this->readPosition += strlen($data);
return $data;
}
private function request_chunk($size) {
$packet = pack('Na*N3', strlen($this->handle), $this->handle, $this->internalPosition / 4294967296, $this->internalPosition, $size);
return $this->sftp->_send_sftp_packet(NET_SFTP_READ, $packet);
}
private function read_chunk() {
$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 $this->eof;
}
public function stream_close() {
if (!$this->sftp->_close_handle($this->handle)) {
return false;
}
}
}