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Issue8273 corrupt nu get cache (#8275)
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Fixes #8273

Context
Prevent overwriting the source of a hard/symbolic link.

Changes Made
Always delete the destination file (unless readonly and OverwriteReadOnlyFiles is false)

Testing
Added unit test.
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@manfred-brands
manfred-brands authored Mar 15, 2023
1 parent 18fe510 commit a93882f
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Showing 3 changed files with 112 additions and 32 deletions.
81 changes: 81 additions & 0 deletions src/Tasks.UnitTests/Copy_Tests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2096,6 +2096,87 @@ public void InvalidErrorIfLinkFailed()
Assert.False(result);
engine.AssertLogContains("MSB3892");
}

/// <summary>
/// An existing link source should not be modified.
/// </summary>
/// <remarks>
/// Related to issue [#8273](https://github.com/dotnet/msbuild/issues/8273)
/// </remarks>
[Theory]
[InlineData(false, false)]
[InlineData(false, true)]
[InlineData(true, false)]
public void DoNotCorruptSourceOfLink(bool useHardLink, bool useSymbolicLink)
{
string sourceFile1 = FileUtilities.GetTemporaryFile();
string sourceFile2 = FileUtilities.GetTemporaryFile();
string temp = Path.GetTempPath();
string destFolder = Path.Combine(temp, "2A333ED756AF4dc392E728D0F864A398");
string destFile = Path.Combine(destFolder, "The Destination");

try
{
File.WriteAllText(sourceFile1, "This is the first source temp file."); // HIGHCHAR: Test writes in UTF8 without preamble.
File.WriteAllText(sourceFile2, "This is the second source temp file."); // HIGHCHAR: Test writes in UTF8 without preamble.

// Don't create the dest folder, let task do that

ITaskItem[] sourceFiles = { new TaskItem(sourceFile1) };
ITaskItem[] destinationFiles = { new TaskItem(destFile) };

var me = new MockEngine(true);
var t = new Copy
{
RetryDelayMilliseconds = 1, // speed up tests!
BuildEngine = me,
SourceFiles = sourceFiles,
DestinationFiles = destinationFiles,
SkipUnchangedFiles = true,
UseHardlinksIfPossible = useHardLink,
UseSymboliclinksIfPossible = useSymbolicLink,
};

bool success = t.Execute();

Assert.True(success); // "success"
Assert.True(File.Exists(destFile)); // "destination exists"

string destinationFileContents = File.ReadAllText(destFile);
Assert.Equal("This is the first source temp file.", destinationFileContents);

sourceFiles = new TaskItem[] { new TaskItem(sourceFile2) };

t = new Copy
{
RetryDelayMilliseconds = 1, // speed up tests!
BuildEngine = me,
SourceFiles = sourceFiles,
DestinationFiles = destinationFiles,
SkipUnchangedFiles = true,
UseHardlinksIfPossible = false,
UseSymboliclinksIfPossible = false,
};

success = t.Execute();

Assert.True(success); // "success"
Assert.True(File.Exists(destFile)); // "destination exists"

destinationFileContents = File.ReadAllText(destFile);
Assert.Equal("This is the second source temp file.", destinationFileContents);

// Read the source file (it should not have been overwritten)
string sourceFileContents = File.ReadAllText(sourceFile1);
Assert.Equal("This is the first source temp file.", sourceFileContents);

((MockEngine)t.BuildEngine).AssertLogDoesntContain("MSB3026"); // Didn't do retries
}
finally
{
Helpers.DeleteFiles(sourceFile1, sourceFile2, destFile);
}
}
}

public class CopyHardLink_Tests : Copy_Tests
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62 changes: 30 additions & 32 deletions src/Tasks/Copy.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -226,8 +226,6 @@ private void LogDiagnostic(string message, params object[] messageArgs)
FileState sourceFileState, // The source file
FileState destinationFileState) // The destination file
{
bool destinationFileExists = false;

if (destinationFileState.DirectoryExists)
{
Log.LogErrorWithCodeFromResources("Copy.DestinationIsDirectory", sourceFileState.Name, destinationFileState.Name);
Expand Down Expand Up @@ -269,7 +267,14 @@ private void LogDiagnostic(string message, params object[] messageArgs)
if (OverwriteReadOnlyFiles)
{
MakeFileWriteable(destinationFileState, true);
destinationFileExists = destinationFileState.FileExists;
}

// If the destination file is a hard or symbolic link, File.Copy would overwrite the source.
// To prevent this, we need to delete the existing entry before we Copy or create a link.
// We could try to figure out if the file is a link, but I can't think of a reason to not simply delete it always.
if (ChangeWaves.AreFeaturesEnabled(ChangeWaves.Wave17_6) && destinationFileState.FileExists && !destinationFileState.IsReadOnly)
{
FileUtilities.DeleteNoThrow(destinationFileState.Name);
}

bool symbolicLinkCreated = false;
Expand All @@ -279,7 +284,7 @@ private void LogDiagnostic(string message, params object[] messageArgs)
// Create hard links if UseHardlinksIfPossible is true
if (UseHardlinksIfPossible)
{
TryCopyViaLink(HardLinkComment, MessageImportance.Normal, sourceFileState, destinationFileState, ref destinationFileExists, out hardLinkCreated, ref errorMessage, (source, destination, errMessage) => NativeMethods.MakeHardLink(destination, source, ref errorMessage, Log));
TryCopyViaLink(HardLinkComment, MessageImportance.Normal, sourceFileState, destinationFileState, out hardLinkCreated, ref errorMessage, (source, destination, errMessage) => NativeMethods.MakeHardLink(destination, source, ref errorMessage, Log));
if (!hardLinkCreated)
{
if (UseSymboliclinksIfPossible)
Expand All @@ -297,13 +302,14 @@ private void LogDiagnostic(string message, params object[] messageArgs)
// Create symbolic link if UseSymboliclinksIfPossible is true and hard link is not created
if (!hardLinkCreated && UseSymboliclinksIfPossible)
{
TryCopyViaLink(SymbolicLinkComment, MessageImportance.Normal, sourceFileState, destinationFileState, ref destinationFileExists, out symbolicLinkCreated, ref errorMessage, (source, destination, errMessage) => NativeMethodsShared.MakeSymbolicLink(destination, source, ref errorMessage));
if (!NativeMethodsShared.IsWindows)
{
errorMessage = Log.FormatResourceString("Copy.NonWindowsLinkErrorMessage", "symlink()", errorMessage);
}
TryCopyViaLink(SymbolicLinkComment, MessageImportance.Normal, sourceFileState, destinationFileState, out symbolicLinkCreated, ref errorMessage, (source, destination, errMessage) => NativeMethodsShared.MakeSymbolicLink(destination, source, ref errorMessage));
if (!symbolicLinkCreated)
{
if (!NativeMethodsShared.IsWindows)
{
errorMessage = Log.FormatResourceString("Copy.NonWindowsLinkErrorMessage", "symlink()", errorMessage);
}

Log.LogMessage(MessageImportance.Normal, RetryingAsFileCopy, sourceFileState.Name, destinationFileState.Name, errorMessage);
}
}
Expand All @@ -324,41 +330,28 @@ private void LogDiagnostic(string message, params object[] messageArgs)
Log.LogMessage(MessageImportance.Normal, FileComment, sourceFilePath, destinationFilePath);

File.Copy(sourceFileState.Name, destinationFileState.Name, true);

// If the destinationFile file exists, then make sure it's read-write.
// The File.Copy command copies attributes, but our copy needs to
// leave the file writeable.
if (sourceFileState.IsReadOnly)
{
destinationFileState.Reset();
MakeFileWriteable(destinationFileState, false);
}
}

// Files were successfully copied or linked. Those are equivalent here.
WroteAtLeastOneFile = true;

destinationFileState.Reset();

// If the destinationFile file exists, then make sure it's read-write.
// The File.Copy command copies attributes, but our copy needs to
// leave the file writeable.
if (sourceFileState.IsReadOnly)
{
MakeFileWriteable(destinationFileState, false);
}

return true;
}

private void TryCopyViaLink(string linkComment, MessageImportance messageImportance, FileState sourceFileState, FileState destinationFileState, ref bool destinationFileExists, out bool linkCreated, ref string errorMessage, Func<string, string, string, bool> createLink)
private void TryCopyViaLink(string linkComment, MessageImportance messageImportance, FileState sourceFileState, FileState destinationFileState, out bool linkCreated, ref string errorMessage, Func<string, string, string, bool> createLink)
{
// Do not log a fake command line as well, as it's superfluous, and also potentially expensive
Log.LogMessage(MessageImportance.Normal, linkComment, sourceFileState.Name, destinationFileState.Name);

if (!OverwriteReadOnlyFiles)
{
destinationFileExists = destinationFileState.FileExists;
}

// CreateHardLink and CreateSymbolicLink cannot overwrite an existing file or link
// so we need to delete the existing entry before we create the hard or symbolic link.
if (destinationFileExists)
{
FileUtilities.DeleteNoThrow(destinationFileState.Name);
}

linkCreated = createLink(sourceFileState.Name, destinationFileState.Name, errorMessage);
}

Expand Down Expand Up @@ -826,6 +819,11 @@ private bool DoCopyWithRetries(FileState sourceFileState, FileState destinationF
LogDiagnostic("Retrying on ERROR_ACCESS_DENIED because MSBUILDALWAYSRETRY = 1");
}
}
else if (code == NativeMethods.ERROR_INVALID_FILENAME)
{
// Invalid characters used in file name, no point retrying.
throw;
}

if (e is UnauthorizedAccessException)
{
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1 change: 1 addition & 0 deletions src/Tasks/NativeMethods.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -537,6 +537,7 @@ internal static class NativeMethods

internal const int HRESULT_E_CLASSNOTREGISTERED = -2147221164;

internal const int ERROR_INVALID_FILENAME = -2147024773; // Illegal characters in name
internal const int ERROR_ACCESS_DENIED = -2147024891; // ACL'd or r/o
internal const int ERROR_SHARING_VIOLATION = -2147024864; // File locked by another use

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