Add TAR tests that verify ExtractToFile works with special files. (#71988)

src/libraries/System.Formats.Tar/tests/System.Formats.Tar.Tests.csproj

@@ -80,6 +80,7 @@
   </ItemGroup>
   <!-- Unix specific files -->
   <ItemGroup Condition="'$(TargetPlatformIdentifier)' != 'windows'">
+    <Compile Include="TarEntry\TarEntry.ExtractToFile.Tests.Unix.cs" />
     <Compile Include="TarFile\TarFile.ExtractToDirectory.File.Tests.Unix.cs" />
     <Compile Include="TarFile\TarFile.ExtractToDirectoryAsync.File.Tests.Unix.cs" />
     <Compile Include="TarReader\TarReader.TarEntry.ExtractToFileAsync.Tests.Unix.cs" />

src/libraries/System.Formats.Tar/tests/TarEntry/TarEntry.ExtractToFile.Tests.Unix.cs

+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using System.Data;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace System.Formats.Tar.Tests
+{
+    public class TarEntry_ExtractToFile_Tests_Unix : TarTestsBase
+    {
+        public static IEnumerable<object[]> GetFormatsAndSpecialFiles()
+        {
+            foreach (TarEntryFormat format in new[] { TarEntryFormat.Ustar, TarEntryFormat.Pax, TarEntryFormat.Gnu }) // V7 does not support special files
+            {
+                foreach (TarEntryType entryType in new[] { TarEntryType.BlockDevice, TarEntryType.CharacterDevice, TarEntryType.Fifo })
+                {
+                    yield return new object[] { format, entryType };
+                }
+            }
+        }
+
+        [ConditionalTheory(nameof(IsRemoteExecutorSupportedAndOnUnixAndSuperUser))]
+        [MemberData(nameof(GetFormatsAndSpecialFiles))]
+        public void Extract_SpecialFiles(TarEntryFormat format, TarEntryType entryType)
+        {
+            using TempDirectory root = new TempDirectory();
+
+            (string entryName, string destination, PosixTarEntry entry) = Prepare_Extract_SpecialFiles(root, format, entryType);
+
+            entry.ExtractToFile(destination, overwrite: true);
+
+            Verify_Extract_SpecialFiles(destination, entry, entryType);
+        }
+
+        [ConditionalTheory(nameof(IsRemoteExecutorSupportedAndOnUnixAndSuperUser))]
+        [MemberData(nameof(GetFormatsAndSpecialFiles))]
+        public async Task Extract_SpecialFiles_Async(TarEntryFormat format, TarEntryType entryType)
+        {
+            using TempDirectory root = new TempDirectory();
+
+            (string entryName, string destination, PosixTarEntry entry) = Prepare_Extract_SpecialFiles(root, format, entryType);
+
+            await entry.ExtractToFileAsync(destination, overwrite: true);
+
+            Verify_Extract_SpecialFiles(destination, entry, entryType);
+        }
+
+        private (string, string, PosixTarEntry) Prepare_Extract_SpecialFiles(TempDirectory root, TarEntryFormat format, TarEntryType entryType)
+        {
+            string entryName = entryType.ToString();
+            string destination = Path.Join(root.Path, entryName);
+
+            PosixTarEntry entry = InvokeTarEntryCreationConstructor(format, entryType, entryName) as PosixTarEntry;
+            Assert.NotNull(entry);
+
+            if (entryType is TarEntryType.BlockDevice)
+            {
+                entry.DeviceMajor = TestBlockDeviceMajor;
+                entry.DeviceMinor = TestBlockDeviceMinor;
+            }
+            else if (entryType is TarEntryType.CharacterDevice)
+            {
+                entry.DeviceMajor = TestCharacterDeviceMajor;
+                entry.DeviceMinor = TestCharacterDeviceMinor;
+            }
+
+            return (entryName, destination, entry);
+        }
+
+        private void Verify_Extract_SpecialFiles(string destination, PosixTarEntry entry, TarEntryType entryType)
+        {
+            Assert.True(File.Exists(destination));
+
+            Interop.Sys.FileStatus status = default;
+            status.Mode = default;
+            status.Dev = default;
+            Interop.CheckIo(Interop.Sys.LStat(destination, out status));
+            int fileType = status.Mode & Interop.Sys.FileTypes.S_IFMT;
+
+            if (entryType is TarEntryType.BlockDevice)
+            {
+                Assert.Equal(Interop.Sys.FileTypes.S_IFBLK, fileType);
+            }
+            else if (entryType is TarEntryType.CharacterDevice)
+            {
+                Assert.Equal(Interop.Sys.FileTypes.S_IFCHR, fileType);
+            }
+            else if (entryType is TarEntryType.Fifo)
+            {
+                Assert.Equal(Interop.Sys.FileTypes.S_IFIFO, fileType);
+            }
+
+            if (entryType is TarEntryType.BlockDevice or TarEntryType.CharacterDevice)
+            {
+                uint major;
+                uint minor;
+                unsafe
+                {
+                    Interop.Sys.GetDeviceIdentifiers((ulong)status.RDev, &major, &minor);
+                }
+
+                Assert.Equal((int)major, entry.DeviceMajor);
+                Assert.Equal((int)minor, entry.DeviceMinor);
+            }
+        }
+    }
+}
\ No newline at end of file