mono/netcore/System.Private.CoreLib/shared/System/Environment.Win32.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System.IO;
using System.Text;
using System.Runtime.InteropServices;

namespace System
{
    public static partial class Environment
    {
        public static string UserName
        {
            get
            {
                // 40 should be enough as we're asking for the SAM compatible name (DOMAIN\User).
                // The max length should be 15 (domain) + 1 (separator) + 20 (name) + null. If for
                // some reason it isn't, we'll grow the buffer.

                // https://support.microsoft.com/en-us/help/909264/naming-conventions-in-active-directory-for-computers-domains-sites-and
                // https://msdn.microsoft.com/en-us/library/ms679635.aspx

                Span<char> initialBuffer = stackalloc char[40];
                var builder = new ValueStringBuilder(initialBuffer);
                GetUserName(ref builder);

                ReadOnlySpan<char> name = builder.AsSpan();
                int index = name.IndexOf('\\');
                if (index != -1)
                {
                    // In the form of DOMAIN\User, cut off DOMAIN\
                    name = name.Slice(index + 1);
                }

                return name.ToString();
            }
        }

        private static void GetUserName(ref ValueStringBuilder builder)
        {
            uint size = 0;
            while (Interop.Secur32.GetUserNameExW(Interop.Secur32.NameSamCompatible, ref builder.GetPinnableReference(), ref size) == Interop.BOOLEAN.FALSE)
            {
                if (Marshal.GetLastWin32Error() == Interop.Errors.ERROR_MORE_DATA)
                {
                    builder.EnsureCapacity(checked((int)size));
                }
                else
                {
                    builder.Length = 0;
                    return;
                }
            }

            builder.Length = (int)size;
        }

        public static string UserDomainName
        {
            get
            {
                // See the comment in UserName
                Span<char> initialBuffer = stackalloc char[40];
                var builder = new ValueStringBuilder(initialBuffer);
                GetUserName(ref builder);

                ReadOnlySpan<char> name = builder.AsSpan();
                int index = name.IndexOf('\\');
                if (index != -1)
                {
                    // In the form of DOMAIN\User, cut off \User and return
                    return name.Slice(0, index).ToString();
                }

                // In theory we should never get use out of LookupAccountNameW as the above API should
                // always return what we need. Can't find any clues in the historical sources, however.

                // Domain names aren't typically long.
                // https://support.microsoft.com/en-us/help/909264/naming-conventions-in-active-directory-for-computers-domains-sites-and
                Span<char> initialDomainNameBuffer = stackalloc char[64];
                var domainBuilder = new ValueStringBuilder(initialBuffer);
                uint length = (uint)domainBuilder.Capacity;

                // This API will fail to return the domain name without a buffer for the SID.
                // SIDs are never over 68 bytes long.
                Span<byte> sid = stackalloc byte[68];
                uint sidLength = 68;

                while (!Interop.Advapi32.LookupAccountNameW(null, ref builder.GetPinnableReference(), ref MemoryMarshal.GetReference(sid),
                    ref sidLength, ref domainBuilder.GetPinnableReference(), ref length, out _))
                {
                    int error = Marshal.GetLastWin32Error();

                    // The docs don't call this out clearly, but experimenting shows that the error returned is the following.
                    if (error != Interop.Errors.ERROR_INSUFFICIENT_BUFFER)
                    {
                        throw new InvalidOperationException(Win32Marshal.GetMessage(error));
                    }

                    domainBuilder.EnsureCapacity((int)length);
                }

                domainBuilder.Length = (int)length;
                return domainBuilder.ToString();
            }
        }

        private static string GetFolderPathCore(SpecialFolder folder, SpecialFolderOption option)
        {
            // We're using SHGetKnownFolderPath instead of SHGetFolderPath as SHGetFolderPath is
            // capped at MAX_PATH.
            //
            // Because we validate both of the input enums we shouldn't have to care about CSIDL and flag
            // definitions we haven't mapped. If we remove or loosen the checks we'd have to account
            // for mapping here (this includes tweaking as SHGetFolderPath would do).
            //
            // The only SpecialFolderOption defines we have are equivalent to KnownFolderFlags.

            string folderGuid;

            switch (folder)
            {
                case SpecialFolder.ApplicationData:
                    folderGuid = Interop.Shell32.KnownFolders.RoamingAppData;
                    break;
                case SpecialFolder.CommonApplicationData:
                    folderGuid = Interop.Shell32.KnownFolders.ProgramData;
                    break;
                case SpecialFolder.LocalApplicationData:
                    folderGuid = Interop.Shell32.KnownFolders.LocalAppData;
                    break;
                case SpecialFolder.Cookies:
                    folderGuid = Interop.Shell32.KnownFolders.Cookies;
                    break;
                case SpecialFolder.Desktop:
                    folderGuid = Interop.Shell32.KnownFolders.Desktop;
                    break;
                case SpecialFolder.Favorites:
                    folderGuid = Interop.Shell32.KnownFolders.Favorites;
                    break;
                case SpecialFolder.History:
                    folderGuid = Interop.Shell32.KnownFolders.History;
                    break;
                case SpecialFolder.InternetCache:
                    folderGuid = Interop.Shell32.KnownFolders.InternetCache;
                    break;
                case SpecialFolder.Programs:
                    folderGuid = Interop.Shell32.KnownFolders.Programs;
                    break;
                case SpecialFolder.MyComputer:
                    folderGuid = Interop.Shell32.KnownFolders.ComputerFolder;
                    break;
                case SpecialFolder.MyMusic:
                    folderGuid = Interop.Shell32.KnownFolders.Music;
                    break;
                case SpecialFolder.MyPictures:
                    folderGuid = Interop.Shell32.KnownFolders.Pictures;
                    break;
                case SpecialFolder.MyVideos:
                    folderGuid = Interop.Shell32.KnownFolders.Videos;
                    break;
                case SpecialFolder.Recent:
                    folderGuid = Interop.Shell32.KnownFolders.Recent;
                    break;
                case SpecialFolder.SendTo:
                    folderGuid = Interop.Shell32.KnownFolders.SendTo;
                    break;
                case SpecialFolder.StartMenu:
                    folderGuid = Interop.Shell32.KnownFolders.StartMenu;
                    break;
                case SpecialFolder.Startup:
                    folderGuid = Interop.Shell32.KnownFolders.Startup;
                    break;
                case SpecialFolder.System:
                    folderGuid = Interop.Shell32.KnownFolders.System;
                    break;
                case SpecialFolder.Templates:
                    folderGuid = Interop.Shell32.KnownFolders.Templates;
                    break;
                case SpecialFolder.DesktopDirectory:
                    folderGuid = Interop.Shell32.KnownFolders.Desktop;
                    break;
                case SpecialFolder.Personal:
                    // Same as Personal
                    // case SpecialFolder.MyDocuments:
                    folderGuid = Interop.Shell32.KnownFolders.Documents;
                    break;
                case SpecialFolder.ProgramFiles:
                    folderGuid = Interop.Shell32.KnownFolders.ProgramFiles;
                    break;
                case SpecialFolder.CommonProgramFiles:
                    folderGuid = Interop.Shell32.KnownFolders.ProgramFilesCommon;
                    break;
                case SpecialFolder.AdminTools:
                    folderGuid = Interop.Shell32.KnownFolders.AdminTools;
                    break;
                case SpecialFolder.CDBurning:
                    folderGuid = Interop.Shell32.KnownFolders.CDBurning;
                    break;
                case SpecialFolder.CommonAdminTools:
                    folderGuid = Interop.Shell32.KnownFolders.CommonAdminTools;
                    break;
                case SpecialFolder.CommonDocuments:
                    folderGuid = Interop.Shell32.KnownFolders.PublicDocuments;
                    break;
                case SpecialFolder.CommonMusic:
                    folderGuid = Interop.Shell32.KnownFolders.PublicMusic;
                    break;
                case SpecialFolder.CommonOemLinks:
                    folderGuid = Interop.Shell32.KnownFolders.CommonOEMLinks;
                    break;
                case SpecialFolder.CommonPictures:
                    folderGuid = Interop.Shell32.KnownFolders.PublicPictures;
                    break;
                case SpecialFolder.CommonStartMenu:
                    folderGuid = Interop.Shell32.KnownFolders.CommonStartMenu;
                    break;
                case SpecialFolder.CommonPrograms:
                    folderGuid = Interop.Shell32.KnownFolders.CommonPrograms;
                    break;
                case SpecialFolder.CommonStartup:
                    folderGuid = Interop.Shell32.KnownFolders.CommonStartup;
                    break;
                case SpecialFolder.CommonDesktopDirectory:
                    folderGuid = Interop.Shell32.KnownFolders.PublicDesktop;
                    break;
                case SpecialFolder.CommonTemplates:
                    folderGuid = Interop.Shell32.KnownFolders.CommonTemplates;
                    break;
                case SpecialFolder.CommonVideos:
                    folderGuid = Interop.Shell32.KnownFolders.PublicVideos;
                    break;
                case SpecialFolder.Fonts:
                    folderGuid = Interop.Shell32.KnownFolders.Fonts;
                    break;
                case SpecialFolder.NetworkShortcuts:
                    folderGuid = Interop.Shell32.KnownFolders.NetHood;
                    break;
                case SpecialFolder.PrinterShortcuts:
                    folderGuid = Interop.Shell32.KnownFolders.PrintersFolder;
                    break;
                case SpecialFolder.UserProfile:
                    folderGuid = Interop.Shell32.KnownFolders.Profile;
                    break;
                case SpecialFolder.CommonProgramFilesX86:
                    folderGuid = Interop.Shell32.KnownFolders.ProgramFilesCommonX86;
                    break;
                case SpecialFolder.ProgramFilesX86:
                    folderGuid = Interop.Shell32.KnownFolders.ProgramFilesX86;
                    break;
                case SpecialFolder.Resources:
                    folderGuid = Interop.Shell32.KnownFolders.ResourceDir;
                    break;
                case SpecialFolder.LocalizedResources:
                    folderGuid = Interop.Shell32.KnownFolders.LocalizedResourcesDir;
                    break;
                case SpecialFolder.SystemX86:
                    folderGuid = Interop.Shell32.KnownFolders.SystemX86;
                    break;
                case SpecialFolder.Windows:
                    folderGuid = Interop.Shell32.KnownFolders.Windows;
                    break;
                default:
                    return string.Empty;
            }

            return GetKnownFolderPath(folderGuid, option);
        }

        private static string GetKnownFolderPath(string folderGuid, SpecialFolderOption option)
        {
            Guid folderId = new Guid(folderGuid);

            int hr = Interop.Shell32.SHGetKnownFolderPath(folderId, (uint)option, IntPtr.Zero, out string path);
            if (hr != 0) // Not S_OK
            {
                return string.Empty;
            }

            return path;
        }
    }
}