/// <summary>
/// Checks that
/// - a sideband file for a given process exists
/// - the sideband file is not corrupt (its checksum checks out)
/// - the process metadata recorded in the sideband file matches the metadata expected for this process
/// </summary>
private bool ValidateSidebandFileForProcess(Process process)
{
var sidebandFile = GetSidebandFile(process);
if (!FileUtilities.FileExistsNoFollow(sidebandFile))
{
return(failed(SidebandIntegrityCheckFailReason.FileNotFound));
}
using (var reader = new SidebandReader(sidebandFile))
{
if (!reader.ReadHeader(ignoreChecksum: false))
{
return(failed(SidebandIntegrityCheckFailReason.ChecksumMismatch));
}
var metadata = reader.ReadMetadata();
var expected = PipExecutor.CreateSidebandMetadata(Scheduler, process);
if (!metadata.Equals(expected))
{
return(failed(SidebandIntegrityCheckFailReason.MetadataMismatch, $"Expected: {expected}. Actual: {metadata}"));
}
return(true);
}
bool failed(SidebandIntegrityCheckFailReason reason, string details = "")
{
Logger.Log.SidebandIntegrityCheckForProcessFailed(LoggingContext, process.FormattedSemiStableHash, sidebandFile, reason.ToString(), details);
return(false);
}
}
private void InvalidateSidebandFile(string sidebandFile, SidebandIntegrityCheckFailReason kind)
{
XAssert.FileExists(sidebandFile, "Sideband file for pipA not found.");
switch (kind)
{
case SidebandIntegrityCheckFailReason.FileNotFound:
AssertDeleteFile(sidebandFile, "Could not delete sideband file for pipA.");
break;
case SidebandIntegrityCheckFailReason.ChecksumMismatch:
File.WriteAllText(path: sidebandFile, contents: "bogus sideband file");
break;
case SidebandIntegrityCheckFailReason.MetadataMismatch:
SidebandMetadata alteredMetadata;
// read the header and the metadata from the original
using (var reader = new SidebandReader(sidebandFile))
{
XAssert.IsTrue(reader.ReadHeader(ignoreChecksum: false));
var originalMetadata = reader.ReadMetadata();
alteredMetadata = new SidebandMetadata(originalMetadata.PipSemiStableHash + 1, originalMetadata.StaticPipFingerprint);
}
// overwrite the original with a different metadata file where PiPSemiStableHash is different than in the original
using (var writer = new SidebandWriter(alteredMetadata, sidebandFile, null))
{
writer.EnsureHeaderWritten();
}
break;
default:
XAssert.Fail($"Unknown kind: {kind}");
break;
}
}
/// <summary>
/// Reads in parallel all writes recorded in given sideband files (<paramref name="sidebandFiles"/>).
/// The task of reading paths from a single sideband file is delegated to <see cref="SidebandReader.ReadSidebandFile"/>.
/// Exceptions of type <see cref="IOException"/> and <see cref="BuildXLException"/> are caught, logged, and ignored.
/// </summary>
internal string[] TryReadAllRecordedWrites(IReadOnlyList <string> sidebandFiles)
{
try
{
return(sidebandFiles
.AsParallel(Context)
.SelectMany(tryReadSidebandFile)
.ToArray());
}
catch (OperationCanceledException)
{
// No specific handling needed for cancellations. Build session will terminate
return(CollectionUtilities.EmptyArray <string>());
}
IEnumerable <string> tryReadSidebandFile(string filename)
{
try
{
return(SidebandReader.ReadSidebandFile(filename, ignoreChecksum: true));
}
catch (Exception e) when(e is BuildXLException || e is IOException || e is OperationCanceledException)
{
Processes.Tracing.Logger.Log.CannotReadSidebandFileWarning(LoggingContext, filename, e.Message);
return(CollectionUtilities.EmptyArray <string>());
}
}
}
/// <summary>
/// Checks that
/// - a sideband file for a given process exists
/// - the sideband file is not corrupt (its checksum checks out)
/// - the process metadata recorded in the sideband file matches the metadata expected for this process
/// Returns true on success and the sideband state in the out parameter
/// </summary>
private bool TryGetAndValidateSidebandStateForProcess(Process process, out IReadOnlyCollection <AbsolutePath> paths)
{
var sidebandFile = GetSidebandFile(process);
paths = null;
if (!FileUtilities.FileExistsNoFollow(sidebandFile))
{
return(failed(SidebandIntegrityCheckFailReason.FileNotFound));
}
using (var reader = new SidebandReader(sidebandFile))
{
if (!reader.ReadHeader(ignoreChecksum: false))
{
return(failed(SidebandIntegrityCheckFailReason.ChecksumMismatch));
}
var metadata = reader.ReadMetadata();
var expected = PipExecutor.CreateSidebandMetadata(Scheduler, process);
if (!metadata.Equals(expected))
{
return(failed(SidebandIntegrityCheckFailReason.MetadataMismatch, $"Expected: {expected}. Actual: {metadata}"));
}
paths = reader.ReadRecordedPaths().Select(p => AbsolutePath.Create(Context.PathTable, p)).ToHashSet();
return(true);
}
bool failed(SidebandIntegrityCheckFailReason reason, string details = "")
{
Logger.Log.SidebandIntegrityCheckForProcessFailed(LoggingContext, process.FormattedSemiStableHash, sidebandFile, reason.ToString(), details);
return(false);
}
}
private bool TryReadSidebandFile(string filename, out SidebandMetadata metadata, out IEnumerable <string> paths)
{
try
{
// We ignore the checksum because even when the sideband file is compromised,
// it is possible to call <see cref="ReadRecordedPaths"/> which will then try to recover
// as many recorded paths as possible.
(paths, metadata) = SidebandReader.ReadSidebandFile(filename, ignoreChecksum: true);
return(true);
}
catch (Exception e) when(e is BuildXLException || e is IOException || e is OperationCanceledException)
{
Processes.Tracing.Logger.Log.CannotReadSidebandFileWarning(LoggingContext, filename, e.Message);
metadata = null;
paths = null;
return(false);
}
}
