Merge pull request #4634 from dferreyra/fix_windows_relative_paths

Fix handling of relative paths when adding prefix to Windows paths.

Duplicati/CommandLine/BackendTool/Program.cs

@@ -25,7 +25,7 @@ using System.Threading;
 
 namespace Duplicati.CommandLine.BackendTool
 {
-    class Program
+    public class Program
     {
         /// <summary>
         /// The main entry point for the application.

Duplicati/Library/Common/Duplicati.Library.Common.csproj

@@ -62,6 +62,8 @@
     <Reference Include="System.Transactions" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="IO\Path.cs" />
+    <Compile Include="IO\PathInternal.Windows.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Platform\Platform.cs" />
     <Compile Include="IO\SystemIO.cs" />

Duplicati/Library/Common/IO/Path.cs

@@ -0,0 +1,59 @@
+// Adapted from https://raw.githubusercontent.com/dotnet/runtime/v5.0.12/src/libraries/System.Private.CoreLib/src/System/IO/Path.cs
+
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// The MIT License (MIT)
+//   
+// Copyright(c).NET Foundation and Contributors
+// 
+// All rights reserved.
+// 
+// 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;
+
+namespace Duplicati.Library.Common.IO
+{
+    public static class DotNetRuntimePathWindows
+    {
+        /// <summary>
+        /// Returns true if the path is fixed to a specific drive or UNC path. This method does no
+        /// validation of the path (URIs will be returned as relative as a result).
+        /// Returns false if the path specified is relative to the current drive or working directory.
+        /// </summary>
+        /// <remarks>
+        /// Handles paths that use the alternate directory separator.  It is a frequent mistake to
+        /// assume that rooted paths <see cref="Path.IsPathRooted(string)"/> are not relative.  This isn't the case.
+        /// "C:a" is drive relative- meaning that it will be resolved against the current directory
+        /// for C: (rooted, but relative). "C:\a" is rooted and not relative (the current directory
+        /// will not be used to modify the path).
+        /// </remarks>
+        /// <exception cref="ArgumentNullException">
+        /// Thrown if <paramref name="path"/> is null.
+        /// </exception>
+        public static bool IsPathFullyQualified(string path)
+        {
+            if (path == null)
+                throw new ArgumentNullException(nameof(path));
+
+            return !PathInternalWindows.IsPartiallyQualified(path);
+        }
+    }
+}

Duplicati/Library/Common/IO/PathInternal.Windows.cs

@@ -0,0 +1,133 @@
+// Adapted from https://github.com/dotnet/runtime/blob/v5.0.12/src/libraries/Common/src/System/IO/PathInternal.Windows.cs
+
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// The MIT License (MIT)
+//   
+// Copyright(c).NET Foundation and Contributors
+// 
+// All rights reserved.
+// 
+// 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.Runtime.CompilerServices;
+using System.IO;
+
+namespace Duplicati.Library.Common.IO
+{
+    /// <summary>Contains internal path helpers that are shared between many projects.</summary>
+    internal static class PathInternalWindows
+    {
+        // All paths in Win32 ultimately end up becoming a path to a File object in the Windows object manager. Passed in paths get mapped through
+        // DosDevice symbolic links in the object tree to actual File objects under \Devices. To illustrate, this is what happens with a typical
+        // path "Foo" passed as a filename to any Win32 API:
+        //
+        //  1. "Foo" is recognized as a relative path and is appended to the current directory (say, "C:\" in our example)
+        //  2. "C:\Foo" is prepended with the DosDevice namespace "\??\"
+        //  3. CreateFile tries to create an object handle to the requested file "\??\C:\Foo"
+        //  4. The Object Manager recognizes the DosDevices prefix and looks
+        //      a. First in the current session DosDevices ("\Sessions\1\DosDevices\" for example, mapped network drives go here)
+        //      b. If not found in the session, it looks in the Global DosDevices ("\GLOBAL??\")
+        //  5. "C:" is found in DosDevices (in our case "\GLOBAL??\C:", which is a symbolic link to "\Device\HarddiskVolume6")
+        //  6. The full path is now "\Device\HarddiskVolume6\Foo", "\Device\HarddiskVolume6" is a File object and parsing is handed off
+        //      to the registered parsing method for Files
+        //  7. The registered open method for File objects is invoked to create the file handle which is then returned
+        //
+        // There are multiple ways to directly specify a DosDevices path. The final format of "\??\" is one way. It can also be specified
+        // as "\\.\" (the most commonly documented way) and "\\?\". If the question mark syntax is used the path will skip normalization
+        // (essentially GetFullPathName()) and path length checks.
+
+        // Windows Kernel-Mode Object Manager
+        // https://msdn.microsoft.com/en-us/library/windows/hardware/ff565763.aspx
+        // https://channel9.msdn.com/Shows/Going+Deep/Windows-NT-Object-Manager
+        //
+        // Introduction to MS-DOS Device Names
+        // https://msdn.microsoft.com/en-us/library/windows/hardware/ff548088.aspx
+        //
+        // Local and Global MS-DOS Device Names
+        // https://msdn.microsoft.com/en-us/library/windows/hardware/ff554302.aspx
+
+        internal const string ExtendedDevicePathPrefix = @"\\?\";
+        internal const string UncPathPrefix = @"\\";
+        internal const string UncDevicePrefixToInsert = @"?\UNC\";
+        internal const string UncExtendedPathPrefix = @"\\?\UNC\";
+        internal const string DevicePathPrefix = @"\\.\";
+
+        internal const int MaxShortPath = 260;
+
+        // \\?\, \\.\, \??\
+        internal const int DevicePrefixLength = 4;
+
+        /// <summary>
+        /// Returns true if the given character is a valid drive letter
+        /// </summary>
+        internal static bool IsValidDriveChar(char value)
+        {
+            return ((value >= 'A' && value <= 'Z') || (value >= 'a' && value <= 'z'));
+        }
+
+        /// <summary>
+        /// Returns true if the path specified is relative to the current drive or working directory.
+        /// Returns false if the path is fixed to a specific drive or UNC path.  This method does no
+        /// validation of the path (URIs will be returned as relative as a result).
+        /// </summary>
+        /// <remarks>
+        /// Handles paths that use the alternate directory separator.  It is a frequent mistake to
+        /// assume that rooted paths (Path.IsPathRooted) are not relative.  This isn't the case.
+        /// "C:a" is drive relative- meaning that it will be resolved against the current directory
+        /// for C: (rooted, but relative). "C:\a" is rooted and not relative (the current directory
+        /// will not be used to modify the path).
+        /// </remarks>
+        internal static bool IsPartiallyQualified(string path)
+        {
+            if (path.Length < 2)
+            {
+                // It isn't fixed, it must be relative.  There is no way to specify a fixed
+                // path with one character (or less).
+                return true;
+            }
+
+            if (IsDirectorySeparator(path[0]))
+            {
+                // There is no valid way to specify a relative path with two initial slashes or
+                // \? as ? isn't valid for drive relative paths and \??\ is equivalent to \\?\
+                return !(path[1] == '?' || IsDirectorySeparator(path[1]));
+            }
+
+            // The only way to specify a fixed path that doesn't begin with two slashes
+            // is the drive, colon, slash format- i.e. C:\
+            return !((path.Length >= 3)
+                && (path[1] == Path.VolumeSeparatorChar)
+                && IsDirectorySeparator(path[2])
+                // To match old behavior we'll check the drive character for validity as the path is technically
+                // not qualified if you don't have a valid drive. "=:\" is the "=" file's default data stream.
+                && IsValidDriveChar(path[0]));
+        }
+
+        /// <summary>
+        /// True if the given character is a directory separator.
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        internal static bool IsDirectorySeparator(char c)
+        {
+            return c == Path.DirectorySeparatorChar || c == Path.AltDirectorySeparatorChar;
+        }
+    }
+}

Duplicati/Library/Common/IO/SystemIOWindows.cs

@@ -29,20 +29,51 @@ namespace Duplicati.Library.Common.IO
 {
     public struct SystemIOWindows : ISystemIO
     {
-        private const string UNCPREFIX = @"\\?\";
-        private const string UNCPREFIX_SERVER = @"\\?\UNC\";
-        private const string PATHPREFIX_SERVER = @"\\";
+        private const string UNCPREFIX = PathInternalWindows.ExtendedDevicePathPrefix;
+        private const string UNCPREFIX_SERVER = PathInternalWindows.UncExtendedPathPrefix;
+        private const string PATHPREFIX_SERVER = PathInternalWindows.UncPathPrefix;
+        private const string PATHPREFIX_SERVER_ALT = @"//";
         private static readonly string DIRSEP = Util.DirectorySeparatorString;
 
+        /// <summary>
+        /// Prefix path with one of the UNC prefixes, but only if it's a fully
+        /// qualified path with no relative components (i.e., with no "." or
+        /// ".." as part of the path).
+        /// </summary>
         public static string PrefixWithUNC(string path)
         {
             if (IsPrefixedWithUNC(path))
             {
+                // For example: \\?\C:\Temp\foo.txt or \\?\UNC\example.com\share\foo.txt
                 return path;
             }
-            return path.StartsWith(PATHPREFIX_SERVER, StringComparison.Ordinal)
-                ? UNCPREFIX_SERVER + path.Substring(PATHPREFIX_SERVER.Length)
-                : UNCPREFIX + path;
+            else
+            {
+                var hasRelativePathComponents = HasRelativePathComponents(path);
+                if (IsPrefixedWithBasicUNC(path) && !hasRelativePathComponents)
+                {
+                    // For example: \\example.com\share\foo.txt or //example.com/share/foo.txt
+                    return UNCPREFIX_SERVER + ConvertSlashes(path.Substring(PATHPREFIX_SERVER.Length));
+                }
+                else if (DotNetRuntimePathWindows.IsPathFullyQualified(path) && !hasRelativePathComponents)
+                {
+                    // For example: C:\Temp\foo.txt or C:/Temp/foo.txt
+                    return UNCPREFIX + ConvertSlashes(path);
+                }
+                else
+                {
+                    // A relative path or a fully qualified path with relative
+                    // path components so the UNC prefix cannot be applied.
+                    // For example: foo.txt or C:\Temp\..\foo.txt
+                    return path;
+                }
+            }
+        }
+
+        private static bool IsPrefixedWithBasicUNC(string path)
+        {
+            return path.StartsWith(PATHPREFIX_SERVER, StringComparison.Ordinal) ||
+                path.StartsWith(PATHPREFIX_SERVER_ALT, StringComparison.Ordinal);
         }
 
         private static bool IsPrefixedWithUNC(string path)
@@ -51,6 +82,32 @@ namespace Duplicati.Library.Common.IO
                 path.StartsWith(UNCPREFIX, StringComparison.Ordinal);
         }
 
+        private static string[] relativePathComponents = new[] { ".", ".." };
+
+        /// <summary>
+        /// Returns true if <paramref name="path"/> contains relative path components; i.e., "." or "..".
+        /// </summary>
+        private static bool HasRelativePathComponents(string path)
+        {
+            return GetPathComponents(path).Any(pathComponent => relativePathComponents.Contains(pathComponent));
+        }
+
+        /// <summary>
+        /// Returns a sequence representing the files and directories in <paramref name="path"/>.
+        /// </summary>
+        private static IEnumerable<string> GetPathComponents(string path)
+        {
+            while (!String.IsNullOrEmpty(path))
+            {
+                var pathComponent = Path.GetFileName(path);
+                if (!String.IsNullOrEmpty(pathComponent))
+                {
+                    yield return pathComponent;
+                }
+                path = Path.GetDirectoryName(path);
+            }
+        }
+
         public static string StripUNCPrefix(string path)
         {
             if (path.StartsWith(UNCPREFIX_SERVER, StringComparison.Ordinal))
@@ -407,13 +464,18 @@ namespace Duplicati.Library.Common.IO
 
         public string PathGetFullPath(string path)
         {
+            // Desired behavior:
+            // 1. If path is already prefixed with \\?\, it should be left untouched
+            // 2. If path is not already prefixed with \\?\, the return value should also not be prefixed
+            // 3. If path is relative or has relative components, that should be resolved by calling Path.GetFullPath()
+            // 4. If path is not relative and has no relative components, prefix with \\?\ to prevent normalization from munging "problematic Windows paths"
             if (IsPrefixedWithUNC(path))
             {
-                return System.IO.Path.GetFullPath(ConvertSlashes(path));
+                return path;
             }
             else
             {
-                return StripUNCPrefix(System.IO.Path.GetFullPath(PrefixWithUNC(ConvertSlashes(path))));
+                return StripUNCPrefix(Path.GetFullPath(PrefixWithUNC(path)));
             }
         }
 

Duplicati/UnitTest/BackendToolTests.cs

@@ -0,0 +1,74 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using Duplicati.Library.Interface;
+using Duplicati.Library.Main;
+using NUnit.Framework;
+
+namespace Duplicati.UnitTest
+{
+    [TestFixture]
+    public class BackendToolTests : BasicSetupHelper
+    {
+        [Test]
+        [Category("BackendTool")]
+        public void Get()
+        {
+            // Files to create in MB.
+            int[] fileSizes = {10, 20, 30};
+            foreach (int size in fileSizes)
+            {
+                var data = new byte[size * 1024 * 1024];
+                var rng = new Random();
+                rng.NextBytes(data);
+                File.WriteAllBytes(Path.Combine(DATAFOLDER, size + "MB"), data);
+            }
+
+            // Run a backup.
+            var options = new Dictionary<string, string>(TestOptions);
+            var backendURL = "file://" + this.TARGETFOLDER;
+            using (Controller c = new Controller(backendURL, options, null))
+            {
+                var backupResults = c.Backup(new[] {DATAFOLDER});
+                Assert.AreEqual(0, backupResults.Errors.Count());
+                Assert.AreEqual(0, backupResults.Warnings.Count());
+            }
+
+            // Get the backend files using absolute paths
+            var absoluteDownloadFolder = Path.Combine(RESTOREFOLDER, "target-files-absolute");
+            Directory.CreateDirectory(absoluteDownloadFolder);
+            foreach (var targetFile in Directory.GetFiles(TARGETFOLDER))
+            {
+                // Absolute path
+                var downloadFileName = Path.Combine(absoluteDownloadFolder, Path.GetFileName(targetFile));
+                var status = CommandLine.BackendTool.Program.RealMain(new[] { "GET", $"{backendURL}", $"{downloadFileName}" });
+                Assert.AreEqual(0, status);
+                Assert.IsTrue(File.Exists(downloadFileName));
+                TestUtils.AssertFilesAreEqual(targetFile, downloadFileName, false, downloadFileName);
+            }
+
+            // Get the backend files using relative paths
+            var relativeDownloadFolder = Path.Combine(RESTOREFOLDER, "target-files-relative");
+            Directory.CreateDirectory(relativeDownloadFolder);
+            var originalCurrentDirectory = Directory.GetCurrentDirectory();
+            Directory.SetCurrentDirectory(relativeDownloadFolder);
+            try
+            {
+                foreach (var targetFile in Directory.GetFiles(TARGETFOLDER))
+                {
+                    // Relative path
+                    var downloadFileName = Path.GetFileName(targetFile);
+                    var status = CommandLine.BackendTool.Program.RealMain(new[] { "GET", $"{backendURL}", $"{downloadFileName}" });
+                    Assert.AreEqual(0, status);
+                    Assert.IsTrue(File.Exists(downloadFileName));
+                    TestUtils.AssertFilesAreEqual(targetFile, downloadFileName, false, downloadFileName);
+                }
+            }
+            finally
+            {
+                Directory.SetCurrentDirectory(originalCurrentDirectory);
+            }
+        }
+    }
+}

Duplicati/UnitTest/Duplicati.UnitTest.csproj

@@ -46,6 +46,7 @@
     <Reference Include="System.Web" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="BackendToolTests.cs" />
     <Compile Include="SymLinkTests.cs" />
     <Compile Include="ControllerTests.cs" />
     <Compile Include="DeleteHandlerTests.cs" />

Duplicati/UnitTest/IOTests.cs

@@ -21,7 +21,8 @@ using NUnit.Framework;
 using Duplicati.Library.Common.IO;
 using Duplicati.Library.Utility;
 using Duplicati.Library.Common;
-
+using System.Collections.Generic;
+
 namespace Duplicati.UnitTest
 {
     [Category("IO")]
@@ -95,5 +96,222 @@ namespace Duplicati.UnitTest
             //In particular don't throw PathTooLongException
             Assert.Throws<System.IO.DirectoryNotFoundException>(() => SystemIO.IO_OS.GetDirectories(longPath));
         }
-    }
-}
+
+        [Test]
+        public void TestPrefixWithUNCInWindowsClient()
+        {
+            if (!Platform.IsClientWindows)
+            {
+                return;
+            }
+
+            var testCasesLeavingPathUnchanged =
+                new[]
+                {
+                    // Normalization of basic relative paths, with both kinds of slashes
+                    @".",
+                    @"temp",
+                    @"temp\file.txt",
+                    @"\",
+                    @"/",
+                    @"\temp",
+                    @"/temp",
+                    @"/temp/file.txt",
+
+                    // Normalization of full qualified paths, but with relative components, with both kinds of slashes
+                    @"C:\temp\.",
+                    @"C:/temp/.",
+                    @"C:\temp\..",
+                    @"C:/temp/..",
+                    @"C:\temp\..\folder",
+                    @"C:/temp/../folder",
+                    @"C:\temp\.\file.txt",
+                    @"C:/temp/./file.txt",
+                    @"\\example.com\share\.",
+                    @"//example.com/share/.",
+                    @"\\example.com\share\..",
+                    @"//example.com/share/..",
+                    @"\\example.com\share\..\folder",
+                    @"//example.com/share/../folder",
+                    @"\\example.com\share\.\file.txt",
+                    @"//example.com/share/./file.txt",
+
+                    // Normalization disabled for paths with @"\\?\" prefix
+                    @"\\?\C:\",
+                    @"\\?\C:\temp",
+                    @"\\?\C:\temp\file.txt",
+                    @"\\?\C:\temp.",
+                    @"\\?\C:\temp.\file.txt",
+                    @"\\?\C:\temp.\file.txt.",
+                    @"\\?\C:\temp ",
+                    @"\\?\C:\temp\file.txt ",
+                    @"\\?\C:\",
+                    @"\\?\UNC\example.com\share",
+                    @"\\?\UNC\example.com\share\file.txt",
+                    @"\\?\UNC\example.com\share.",
+                    @"\\?\UNC\example.com\share.\file.txt",
+                    @"\\?\UNC\example.com\share.\file.txt.",
+                    @"\\?\UNC\example.com\share ",
+                    @"\\?\UNC\example.com\share\file.txt "
+                };
+            foreach (var path in testCasesLeavingPathUnchanged)
+            {
+                var actual = SystemIOWindows.PrefixWithUNC(path);
+                var expected = path;
+                Assert.AreEqual(expected, actual, $"Path: {path}");
+            }
+
+            var testCasesWherePrefixIsApplied =
+                new Dictionary<string, string>()
+                {
+                    // Fully qualified paths with no relative components, with both kinds of slashes
+                    { @"C:\", @"\\?\C:\" },
+                    { @"C:/", @"\\?\C:\" },
+                    { @"C:\temp", @"\\?\C:\temp" },
+                    { @"C:/temp", @"\\?\C:\temp" },
+                    { @"C:\temp\file.txt", @"\\?\C:\temp\file.txt" },
+                    { @"C:/temp/file.txt", @"\\?\C:\temp\file.txt" },
+                    { @"\\example.com\share", @"\\?\UNC\example.com\share" },
+                    { @"//example.com/share", @"\\?\UNC\example.com\share" },
+                    { @"\\example.com\share\file.txt", @"\\?\UNC\example.com\share\file.txt" },
+                    { @"//example.com/share/file.txt", @"\\?\UNC\example.com\share\file.txt" },
+                    
+                    // Fully qualified paths with no relative components, but with problematic names, with both kinds of slashes
+                    { @"C:\temp.", @"\\?\C:\temp." },
+                    { @"C:/temp.", @"\\?\C:\temp." },
+                    { @"C:\temp.\file.txt", @"\\?\C:\temp.\file.txt" },
+                    { @"C:/temp./file.txt", @"\\?\C:\temp.\file.txt" },
+                    { @"C:\temp.\file.txt.", @"\\?\C:\temp.\file.txt." },
+                    { @"C:/temp./file.txt.", @"\\?\C:\temp.\file.txt." },
+                    { @"C:\temp ", @"\\?\C:\temp " },
+                    { @"C:/temp ", @"\\?\C:\temp " },
+                    { @"C:\temp\file.txt ", @"\\?\C:\temp\file.txt " },
+                    { @"C:/temp/file.txt ", @"\\?\C:\temp\file.txt " },
+                    { @"\\example.com\share.", @"\\?\UNC\example.com\share." },
+                    { @"//example.com/share.", @"\\?\UNC\example.com\share." },
+                    { @"\\example.com\share\file.txt.", @"\\?\UNC\example.com\share\file.txt." },
+                    { @"//example.com/share./file.txt.", @"\\?\UNC\example.com\share.\file.txt." },
+                    { @"\\example.com\share ", @"\\?\UNC\example.com\share " },
+                    { @"//example.com/share ", @"\\?\UNC\example.com\share " },
+                    { @"\\example.com\share\file.txt ", @"\\?\UNC\example.com\share\file.txt " },
+                    { @"//example.com/share/file.txt ", @"\\?\UNC\example.com\share\file.txt " }
+                };
+            foreach (var keyValuePair in testCasesWherePrefixIsApplied)
+            {
+                var path = keyValuePair.Key;
+                var actual = SystemIOWindows.PrefixWithUNC(path);
+                var expected = keyValuePair.Value;
+                Assert.AreEqual(expected, actual, $"Path: {path}");
+            }
+        }
+
+        [Test]
+        public void TestPathGetFullPathInWindowsClient()
+        {
+            if (!Platform.IsClientWindows)
+            {
+                return;
+            }
+
+            var testCasesWherePathGetFullGivesSameResultsAsDotNet =
+                new[]
+                {
+                    // Normalization of basic relative paths, with both kinds of slashes
+                    @".",
+                    @"temp",
+                    @"temp\file.txt",
+                    @"\",
+                    @"/",
+                    @"\temp",
+                    @"/temp",
+                    @"/temp/file.txt",
+                    @"/temp/file.txt",
+                    
+                    // Normalization of full qualified paths, but with relative components, with both kinds of slashes
+                    @"C:\temp\.",
+                    @"C:/temp/.",
+                    @"C:\temp\..",
+                    @"C:/temp/..",
+                    @"C:\temp\..\folder",
+                    @"C:/temp/../folder",
+                    @"C:\temp\.\file.txt",
+                    @"C:/temp/./file.txt",
+                    @"\\example.com\share\.",
+                    @"//example.com/share/.",
+                    @"\\example.com\share\..",
+                    @"//example.com/share/..",
+                    @"\\example.com\share\..\folder",
+                    @"//example.com/share/../folder",
+                    @"\\example.com\share\.\file.txt",
+                    @"//example.com/share/./file.txt",
+                    
+                    // Fully qualified paths with no relative components, with both kinds of slashes
+                    @"C:\",
+                    @"C:/",
+                    @"C:\temp",
+                    @"C:/temp",
+                    @"C:\temp\file.txt",
+                    @"C:/temp/file.txt",
+                    @"\\example.com\share",
+                    @"//example.com/share",
+                    @"\\example.com\share\file.txt",
+                    @"//example.com/share/file.txt",
+                    
+                    // Normalization disabled for paths with @"\\?\" prefix
+                    @"\\?\C:\",
+                    @"\\?\C:\temp",
+                    @"\\?\C:\temp\file.txt",
+                    @"\\?\C:\temp.",
+                    @"\\?\C:\temp.\file.txt",
+                    @"\\?\C:\temp.\file.txt.",
+                    @"\\?\C:\temp ",
+                    @"\\?\C:\temp\file.txt ",
+                    @"\\?\C:\",
+                    @"\\?\UNC\example.com\share",
+                    @"\\?\UNC\example.com\share\file.txt",
+                    @"\\?\UNC\example.com\share.",
+                    @"\\?\UNC\example.com\share.\file.txt",
+                    @"\\?\UNC\example.com\share.\file.txt.",
+                    @"\\?\UNC\example.com\share ",
+                    @"\\?\UNC\example.com\share\file.txt ",
+                };
+            foreach (var path in testCasesWherePathGetFullGivesSameResultsAsDotNet)
+            {
+                var actual = SystemIO.IO_WIN.PathGetFullPath(path);
+                var expected = System.IO.Path.GetFullPath(path);
+                Assert.AreEqual(expected, actual, $"Path: {path}");
+            }
+
+            var testCasesWherePathGetFullGivesDifferentResultsThanDotNet =
+                new Dictionary<string, string>()
+                {
+                    // Fully qualified paths with no relative components, but with problematic names, with both kinds of slashes
+                    { @"C:\temp.", @"C:\temp." },
+                    { @"C:/temp.", @"C:\temp." },
+                    { @"C:\temp.\file.txt", @"C:\temp.\file.txt" },
+                    { @"C:/temp./file.txt", @"C:\temp.\file.txt" },
+                    { @"C:\temp.\file.txt.", @"C:\temp.\file.txt." },
+                    { @"C:/temp./file.txt.", @"C:\temp.\file.txt." },
+                    { @"C:\temp ", @"C:\temp " },
+                    { @"C:/temp ", @"C:\temp " },
+                    { @"C:\temp\file.txt ", @"C:\temp\file.txt " },
+                    { @"C:/temp/file.txt ", @"C:\temp\file.txt " },
+                    { @"\\example.com\share.", @"\\example.com\share." },
+                    { @"//example.com/share.", @"\\example.com\share." },
+                    { @"\\example.com\share\file.txt.", @"\\example.com\share\file.txt." },
+                    { @"//example.com/share./file.txt.", @"\\example.com\share.\file.txt." },
+                    { @"\\example.com\share ", @"\\example.com\share " },
+                    { @"//example.com/share ", @"\\example.com\share " },
+                    { @"\\example.com\share\file.txt ", @"\\example.com\share\file.txt " },
+                    { @"//example.com/share/file.txt ", @"\\example.com\share\file.txt " },
+                };
+            foreach (var keyValuePair in testCasesWherePathGetFullGivesDifferentResultsThanDotNet)
+            {
+                var path = keyValuePair.Key;
+                var actual = SystemIO.IO_WIN.PathGetFullPath(path);
+                var expected = keyValuePair.Value;
+                Assert.AreEqual(expected, actual, $"Path: {path}");
+            }
+        }
+    }
+}