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[LLVM][Cygwin] add workaround for blocking connect/accept in AF_UNIX sockets #140353

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Merged
mstorsjo merged 1 commit into from
May 22, 2025
Merged

[LLVM][Cygwin] add workaround for blocking connect/accept in AF_UNIX sockets #140353

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18 changes: 18 additions & 0 deletions llvm/lib/Support/raw_socket_stream.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,15 @@ static Expected<int> getSocketFD(StringRef SocketPath) {
"Create socket failed");
}

#ifdef __CYGWIN__
// On Cygwin, UNIX sockets involve a handshake between connect and accept
// to enable SO_PEERCRED/getpeereid handling. This necessitates accept being
// called before connect can return, but at least the tests in
// llvm/unittests/Support/raw_socket_stream_test do both on the same thread
// (first connect and then accept), resulting in a deadlock. This call turns
// off the handshake (and SO_PEERCRED/getpeereid support).
setsockopt(Socket, SOL_SOCKET, SO_PEERCRED, NULL, 0);
#endif
struct sockaddr_un Addr = setSocketAddr(SocketPath);
if (::connect(Socket, (struct sockaddr *)&Addr, sizeof(Addr)) == -1)
return llvm::make_error<StringError>(getLastSocketErrorCode(),
Expand Down Expand Up @@ -147,6 +156,15 @@ Expected<ListeningSocket> ListeningSocket::createUnix(StringRef SocketPath,
return llvm::make_error<StringError>(getLastSocketErrorCode(),
"socket create failed");

#ifdef __CYGWIN__
// On Cygwin, UNIX sockets involve a handshake between connect and accept
// to enable SO_PEERCRED/getpeereid handling. This necessitates accept being
// called before connect can return, but at least the tests in
// llvm/unittests/Support/raw_socket_stream_test do both on the same thread
// (first connect and then accept), resulting in a deadlock. This call turns
// off the handshake (and SO_PEERCRED/getpeereid support).
setsockopt(Socket, SOL_SOCKET, SO_PEERCRED, NULL, 0);
#endif
struct sockaddr_un Addr = setSocketAddr(SocketPath);
if (::bind(Socket, (struct sockaddr *)&Addr, sizeof(Addr)) == -1) {
// Grab error code from call to ::bind before calling ::close
Expand Down