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duplicati/Duplicati/Library/Backend/CIFS/CIFS.cs
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C#

// Copyright (C) 2025, The Duplicati Team
// https://duplicati.com, hello@duplicati.com
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
using System;
using Duplicati.Library.Interface;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Duplicati.Library.Backend.CIFS;
using Duplicati.Library.Backend.CIFS.Model;
using SMBLibrary;
using Duplicati.Library.SourceProvider;
using System.Runtime.CompilerServices;
using Duplicati.Library.Common.IO;
using System.Runtime.CompilerServices;
namespace Duplicati.Library.Backend;
/// <summary>
/// Native CIFS/SMB Backend implementation
/// </summary>
public class CIFSBackend : IStreamingBackend, IFolderEnabledBackend
{
/// <summary>
/// Implementation of interface property for the backend key
/// </summary>
public string ProtocolKey => "cifs";
/// <summary>
/// Implementation of interface property for the backend display name
/// </summary>
public string DisplayName => Strings.CIFSBackend.DisplayName;
/// <summary>
/// Implementation of interface property for the backend description
/// </summary>
public string Description => Strings.CIFSBackend.Description;
/// <summary>
/// Hostname only (no ports or paths) to be used on DNS resolutions.
/// </summary>
private string _DnsName;
/// <summary>
/// Path separators (both Windows \ and unix /) to be used in path manipulation
/// </summary>
private static readonly char[] PATH_SEPARATORS = ['/', '\\'];
/// <summary>
/// Cache of parsed connection parameters
/// </summary>
private SMBConnectionParameters _connectionParameters;
/// <summary>
/// Shared connection between all methods to avoid re-authentication
/// </summary>
private SMBShareConnection _sharedConnection;
/// <summary>
/// Read buffer size for SMB operations (will be capped automatically by SMB negotiated values)
/// </summary>
private const string READ_BUFFER_SIZE_OPTION = "read-buffer-size";
/// <summary>
/// Write buffer size for SMB operations (will be capped automatically by SMB negotiated values)
/// </summary>
private const string WRITE_BUFFER_SIZE_OPTION = "write-buffer-size";
/// <summary>
/// Backend option for controlling the transport (directtcp or netbios)
/// </summary>
private const string TRANSPORT_OPTION = "transport";
/// <summary>
/// Domain (complementary part of authentication) option
/// </summary>
private const string AUTH_DOMAIN_OPTION = "auth-domain";
/// <summary>
/// Username for authentication
/// </summary>
private const string AUTH_USERNAME_OPTION = "auth-username";
/// <summary>
/// Password for authentication
/// </summary>
private const string AUTH_PASSWORD_OPTION = "auth-password";
/// <summary>
/// Defines the default transport to be used in CIFS connection
/// </summary>
private const string DEFAULT_TRANSPORT = "directtcp";
/// <summary>
/// Mapping of transport string to SMBTransportType enum to be used in parsing the option string
/// </summary>
private readonly Dictionary<string, SMBTransportType> _transportMap = new()
{
["directtcp"] = SMBTransportType.DirectTCPTransport,
["netbios"] = SMBTransportType.NetBiosOverTCP
};
/// <summary>
/// Empty constructor is required for the backend to be loaded by the backend factory
/// </summary>
public CIFSBackend()
{
}
/// <summary>
/// Actual constructor for the backend that accepts the url and options
/// </summary>
/// <param name="url">URL in Duplicati Uri format</param>
/// <param name="options">options to be used in the backend</param>
public CIFSBackend(string url, Dictionary<string, string> options)
{
if (string.IsNullOrEmpty(url))
throw new ArgumentNullException(nameof(url));
if (options == null)
throw new ArgumentNullException(nameof(options));
var uri = new Utility.Uri(url);
uri.RequireHost();
_DnsName = uri.Host;
var input = uri.Path.TrimEnd('/');
var slashIndex = input.IndexOf('/'); // Find first slash to separate server and share if present.
options.TryGetValue(AUTH_USERNAME_OPTION, out string authUsername);
options.TryGetValue(AUTH_PASSWORD_OPTION, out string authPassword);
options.TryGetValue(AUTH_DOMAIN_OPTION, out string authDomain);
options.TryGetValue(TRANSPORT_OPTION, out string transport);
int? readBufferSize = null, writeBufferSize = null;
options.TryGetValue(READ_BUFFER_SIZE_OPTION, out string readBufferSizeConfig);
if (!string.IsNullOrWhiteSpace(readBufferSizeConfig)) readBufferSize = Int32.TryParse(readBufferSizeConfig, out int value) ? value : null;
options.TryGetValue(WRITE_BUFFER_SIZE_OPTION, out string writeBufferSizeConfig);
if (!string.IsNullOrWhiteSpace(writeBufferSizeConfig)) writeBufferSize = Int32.TryParse(readBufferSizeConfig, out int value) ? value : null;
// Normalize to 10KB minimum buffers size
readBufferSize = readBufferSize < 1024 * 10 ? null : readBufferSize;
writeBufferSize = writeBufferSize < 1024 * 10 ? null : writeBufferSize;
SMBTransportType transportType = _transportMap.TryGetValue(
string.IsNullOrEmpty(transport) ? DEFAULT_TRANSPORT : transport.ToLower(),
out SMBTransportType type)
? type
: throw new UserInformationException($"Transport must be one of: {string.Join(", ", _transportMap.Keys)}", "CIFSConfig");
_connectionParameters = new SMBConnectionParameters(
uri.Host,
transportType,
slashIndex >= 0 ? input[..slashIndex] : input,
slashIndex >= 0 ? input[(slashIndex + 1)..] : "",
authDomain,
authUsername,
authPassword,
readBufferSize,
writeBufferSize
);
}
/// <summary>
/// Implementation of interface property to return supported command parameters
/// </summary>
public IList<ICommandLineArgument> SupportedCommands =>
new List<ICommandLineArgument>([
new CommandLineArgument(AUTH_PASSWORD_OPTION, CommandLineArgument.ArgumentType.Password, Strings.CIFSBackend.DescriptionAuthPasswordShort, Strings.CIFSBackend.DescriptionAuthPasswordLong),
new CommandLineArgument(AUTH_USERNAME_OPTION, CommandLineArgument.ArgumentType.String, Strings.CIFSBackend.DescriptionAuthUsernameShort, Strings.CIFSBackend.DescriptionAuthUsernameLong),
new CommandLineArgument(AUTH_DOMAIN_OPTION, CommandLineArgument.ArgumentType.String, Strings.CIFSBackend.DescriptionAuthDomainShort, Strings.CIFSBackend.DescriptionAuthDomainLong),
new CommandLineArgument(TRANSPORT_OPTION, CommandLineArgument.ArgumentType.Enumeration, Strings.Options.TransportShort, Strings.Options.TransportLong, DEFAULT_TRANSPORT, null, _transportMap.Keys.ToArray()),
new CommandLineArgument(READ_BUFFER_SIZE_OPTION, CommandLineArgument.ArgumentType.String, Strings.Options.DescriptionReadBufferSizeShort, Strings.Options.DescriptionReadBufferSizeLong),
new CommandLineArgument(WRITE_BUFFER_SIZE_OPTION, CommandLineArgument.ArgumentType.String, Strings.Options.DescriptionWriteBufferSizeShort, Strings.Options.DescriptionWriteBufferSizeLong)
]);
/// <summary>
/// Implementation of interface method for listing remote folder contents
/// </summary>
/// <returns>List of IFileEntry with directory listing result</returns>
public async IAsyncEnumerable<IFileEntry> ListAsync([EnumeratorCancellation] CancellationToken cancellationToken)
{
foreach (var v in await GetConnection().ListAsync(_connectionParameters.Path, cancellationToken).ConfigureAwait(false))
yield return v;
}
/// <summary>
/// Upload files to remote location
/// </summary>
/// <param name="remotename">Filename at remote location</param>
/// <param name="localname">Filename to read from</param>
/// <param name="cancellationToken">CancellationToken that is combined with internal timeout token</param>
/// <exception cref="FileMissingException">FileMissingException when file is not found</exception>
/// <exception cref="Exception">Exceptions arising from either code execution</exception>
public async Task PutAsync(string remotename, string localname, CancellationToken cancellationToken)
{
await using var fs = File.Open(localname,
FileMode.Open, FileAccess.Read, FileShare.Read);
await PutAsync(remotename, fs, cancellationToken).ConfigureAwait(false);
}
/// <summary>
/// Upload files to remote location
/// </summary>
/// <param name="remotename">Filename at remote location</param>
/// <param name="input">Stream to read from</param>
/// <param name="cancellationToken">CancellationToken that is combined with internal timeout token</param>
/// <exception cref="FileMissingException">FileMissingException when file is not found</exception>
/// <exception cref="Exception">Exceptions arising from either code execution</exception>
public async Task PutAsync(string remotename, Stream input, CancellationToken cancellationToken)
{
await GetConnection().PutAsync(remotename, input, cancellationToken).ConfigureAwait(false);
}
/// <summary>
/// Download files from remote
/// </summary>
/// <param name="remotename">Filename at remote location</param>
/// <param name="localname">Local filename to write to</param>
/// <param name="cancellationToken">CancellationToken that is combined with internal timeout token</param>
/// <exception cref="FileMissingException">FileMissingException when file is not found</exception>
/// <exception cref="Exception">Exceptions arising from either code execution or FileMissingException</exception>
public async Task GetAsync(string remotename, string localname, CancellationToken cancellationToken)
{
await using var fs = File.Open(localname,
FileMode.Create, FileAccess.Write,
FileShare.None);
await GetAsync(remotename, fs, cancellationToken).ConfigureAwait(false);
}
/// <summary>
/// Download files from remote
/// </summary>
/// <param name="remotename">Filename at remote location</param>
/// <param name="output">Destination stream to write to</param>
/// <param name="cancellationToken">CancellationToken that is combined with internal timeout token</param>
/// <exception cref="FileMissingException">FileMissingException when file is not found</exception>
/// <exception cref="Exception">Exceptions arising from either code execution or FileMissingException</exception>
public async Task GetAsync(string remotename, Stream output, CancellationToken cancellationToken)
{
await GetConnection().GetAsync(remotename, output, cancellationToken).ConfigureAwait(false);
}
/// <summary>
/// Delete remote file if it exists, if not, throws FileMissingException
/// </summary>
/// <param name="remotename">filename to be deleted on the remote</param>
/// <param name="cancellationToken">CancellationToken that is combined with internal timeout token</param>
/// <returns></returns>
/// <exception cref="FileMissingException">FileMissingException when file is not found</exception>
/// <exception cref="Exception">Exceptions arising from either code execution or business logic errors</exception>
public async Task DeleteAsync(string remotename, CancellationToken cancellationToken)
{
await GetConnection().DeleteAsync(remotename, cancellationToken).ConfigureAwait(false);
}
/// <summary>
/// Implementation of interface function to return hosnames used by the backend
/// </summary>
/// <param name="cancellationToken">CancellationToken, in this call not used.</param>
/// <returns></returns>
public Task<string[]> GetDNSNamesAsync(CancellationToken cancellationToken) =>
Task.FromResult(new[] { _DnsName ?? string.Empty });
/// <summary>
/// Tests backend connectivity by verifying the configured path exists
/// </summary>
/// <param name="cancellationToken">The cancellation token (not used)</param>
/// <exception cref="FolderMissingException">Thrown when configured path does not exist</exception>
public async Task TestAsync(CancellationToken cancellationToken)
{
// This will throw an exception if the folder is missing
await GetConnection().ListAsync(_connectionParameters.Path, cancellationToken).ConfigureAwait(false);
}
/// <summary>
/// Creates the configured remote folder path if it doesn't exist
/// </summary>
/// <param name="cancellationToken">CancellationToken that will be combined with internal timeout token</param>
/// <returns>Task representing the asynchronous operation</returns>
/// <exception cref="Exception">Thrown when folder creation fails</exception>
public async Task CreateFolderAsync(CancellationToken cancellationToken)
{
var pathParts = _connectionParameters.Path?
.Split(PATH_SEPARATORS, StringSplitOptions.RemoveEmptyEntries);
if (pathParts == null || pathParts.Length == 0)
return;
await GetConnection().CreateFolderAsync(_connectionParameters.Path, cancellationToken)
.ConfigureAwait(false);
}
/// <summary>
/// Gets or creates a shared SMB connection
/// </summary>
/// <returns>An SMB connection that can be used for file operations</returns>
private SMBShareConnection GetConnection() => _sharedConnection ??= new SMBShareConnection(_connectionParameters);
/// <summary>
/// Implementation of Dispose pattern enforced by interface
/// </summary>
public void Dispose()
{
try
{
_sharedConnection?.Dispose();
}
catch (Exception ex)
{
// Log the exception but don't rethrow since we're in Dispose
System.Diagnostics.Debug.WriteLine($"Error disposing CIFS connection: {ex.Message}");
}
}
/// <inheritdoc/>
public async IAsyncEnumerable<IFileEntry> ListAsync(string path, [EnumeratorCancellation] CancellationToken cancellationToken)
{
var sourcePath = _connectionParameters.Path;
if (!string.IsNullOrWhiteSpace(sourcePath))
sourcePath = Util.AppendDirSeparator(sourcePath, "/");
foreach (var v in await GetConnection().ListAsync(sourcePath + BackendSourceFileEntry.NormalizePathTo(path, '/'), cancellationToken).ConfigureAwait(false))
if (v.Name != "." && v.Name != "..")
yield return v;
}
/// <inheritdoc/>
public Task<IFileEntry> GetEntryAsync(string path, CancellationToken cancellationToken)
=> Task.FromResult<IFileEntry>(null);
}