https://github.com/charles-zablit created https://github.com/llvm/llvm-project/pull/207017
A closed pipe write end is EOF, not an error. On POSIX, `read()` returns 0, but on Windows `ReadFile` fails with `ERROR_BROKEN_PIPE`. The lldb-server `gdbserver/platform` pipe synchronization in `GDBRemoteCommunication::StartDebugserverProcess` reads the pipe until EOF, so without this it sees an error instead of EOF and reports the sync as failed. Translate both broken-pipe conditions to a zero-length read so cross-platform callers can detect EOF uniformly. >From 218f97a8ace4b54d3d284542ba6590478cb069d5 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Wed, 1 Jul 2026 16:54:22 +0100 Subject: [PATCH] [lldb][Windows] Return EOF from PipeWindows::Read on a closed write end --- lldb/source/Host/windows/PipeWindows.cpp | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/lldb/source/Host/windows/PipeWindows.cpp b/lldb/source/Host/windows/PipeWindows.cpp index e2a64e65cee00..abf608750e61a 100644 --- a/lldb/source/Host/windows/PipeWindows.cpp +++ b/lldb/source/Host/windows/PipeWindows.cpp @@ -291,8 +291,15 @@ llvm::Expected<size_t> PipeWindows::Read(void *buf, size_t size, return bytes_read; DWORD failure_error = ::GetLastError(); - if (failure_error != ERROR_IO_PENDING) + switch (failure_error) { + case ERROR_BROKEN_PIPE: + case ERROR_HANDLE_EOF: + return 0; + case ERROR_IO_PENDING: + break; + default: return Status(failure_error, eErrorTypeWin32).takeError(); + } DWORD timeout_msec = timeout ? std::chrono::ceil<std::chrono::milliseconds>(*timeout).count() @@ -319,8 +326,13 @@ llvm::Expected<size_t> PipeWindows::Read(void *buf, size_t size, // Now we call GetOverlappedResult setting bWait to false, since we've // already waited as long as we're willing to. - if (!::GetOverlappedResult(m_read, &m_read_overlapped, &bytes_read, FALSE)) - return Status(::GetLastError(), eErrorTypeWin32).takeError(); + if (!::GetOverlappedResult(m_read, &m_read_overlapped, &bytes_read, FALSE)) { + DWORD overlapped_error = ::GetLastError(); + if (overlapped_error == ERROR_BROKEN_PIPE || + overlapped_error == ERROR_HANDLE_EOF) + return 0; + return Status(overlapped_error, eErrorTypeWin32).takeError(); + } return bytes_read; } _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
