[Lldb-commits] [lldb] [lldb] Add Socket::CreatePair (PR #145015)
Pavel Labath via lldb-commits
lldb-commits at lists.llvm.org
Fri Jun 20 03:58:54 PDT 2025
https://github.com/labath created https://github.com/llvm/llvm-project/pull/145015
It creates a pair of connected sockets using the simplest mechanism for the given platform (TCP on windows, socketpair(2) elsewhere).
Main motivation is to remove the ugly platform-specific code in ProcessGDBRemote::LaunchAndConnectToDebugserver, but it can also be used in other places where we need to create a pair of connected sockets.
>From 54ef8f5e1ff3f3ea28605ffb9a90f0b0aa6b52af Mon Sep 17 00:00:00 2001
From: Pavel Labath <pavel at labath.sk>
Date: Thu, 19 Jun 2025 21:44:02 +0200
Subject: [PATCH] [lldb] Add Socket::CreatePair
It creates a pair of connected sockets using the simplest mechanism for
the given platform (TCP on windows, socketpair(2) elsewhere).
Main motivation is to remove the ugly platform-specific code in
ProcessGDBRemote::LaunchAndConnectToDebugserver, but it can also be used
in other places where we need to create a pair of connected sockets.
---
lldb/include/lldb/Host/Socket.h | 4 +++
lldb/include/lldb/Host/common/TCPSocket.h | 4 +++
lldb/include/lldb/Host/posix/DomainSocket.h | 4 +++
lldb/source/Host/common/Socket.cpp | 17 +++++++++
lldb/source/Host/common/TCPSocket.cpp | 28 +++++++++++++++
lldb/source/Host/posix/DomainSocket.cpp | 29 +++++++++++++++
.../gdb-remote/GDBRemoteCommunication.cpp | 36 +++++--------------
lldb/unittests/Core/CommunicationTest.cpp | 26 ++++++++------
lldb/unittests/Host/SocketTest.cpp | 35 ++++++++++++++++++
9 files changed, 144 insertions(+), 39 deletions(-)
diff --git a/lldb/include/lldb/Host/Socket.h b/lldb/include/lldb/Host/Socket.h
index c313aa4f6d26b..14a9660ed30b7 100644
--- a/lldb/include/lldb/Host/Socket.h
+++ b/lldb/include/lldb/Host/Socket.h
@@ -106,6 +106,10 @@ class Socket : public IOObject {
static std::unique_ptr<Socket> Create(const SocketProtocol protocol,
Status &error);
+ static llvm::Expected<
+ std::pair<std::unique_ptr<Socket>, std::unique_ptr<Socket>>>
+ CreatePair(std::optional<SocketProtocol> protocol = std::nullopt);
+
virtual Status Connect(llvm::StringRef name) = 0;
virtual Status Listen(llvm::StringRef name, int backlog) = 0;
diff --git a/lldb/include/lldb/Host/common/TCPSocket.h b/lldb/include/lldb/Host/common/TCPSocket.h
index cb950c0015ea6..e81cb82dbcba1 100644
--- a/lldb/include/lldb/Host/common/TCPSocket.h
+++ b/lldb/include/lldb/Host/common/TCPSocket.h
@@ -23,6 +23,10 @@ class TCPSocket : public Socket {
TCPSocket(NativeSocket socket, bool should_close);
~TCPSocket() override;
+ static llvm::Expected<
+ std::pair<std::unique_ptr<TCPSocket>, std::unique_ptr<TCPSocket>>>
+ CreatePair();
+
// returns port number or 0 if error
uint16_t GetLocalPortNumber() const;
diff --git a/lldb/include/lldb/Host/posix/DomainSocket.h b/lldb/include/lldb/Host/posix/DomainSocket.h
index a840d474429ec..c3a6a64bbdef8 100644
--- a/lldb/include/lldb/Host/posix/DomainSocket.h
+++ b/lldb/include/lldb/Host/posix/DomainSocket.h
@@ -19,6 +19,10 @@ class DomainSocket : public Socket {
DomainSocket(NativeSocket socket, bool should_close);
explicit DomainSocket(bool should_close);
+ static llvm::Expected<
+ std::pair<std::unique_ptr<DomainSocket>, std::unique_ptr<DomainSocket>>>
+ CreatePair();
+
Status Connect(llvm::StringRef name) override;
Status Listen(llvm::StringRef name, int backlog) override;
diff --git a/lldb/source/Host/common/Socket.cpp b/lldb/source/Host/common/Socket.cpp
index 5c5cd653c3d9e..c9dec0f8ea22a 100644
--- a/lldb/source/Host/common/Socket.cpp
+++ b/lldb/source/Host/common/Socket.cpp
@@ -234,6 +234,23 @@ std::unique_ptr<Socket> Socket::Create(const SocketProtocol protocol,
return socket_up;
}
+llvm::Expected<std::pair<std::unique_ptr<Socket>, std::unique_ptr<Socket>>>
+Socket::CreatePair(std::optional<SocketProtocol> protocol) {
+ constexpr SocketProtocol kBestProtocol =
+ LLDB_ENABLE_POSIX ? ProtocolUnixDomain : ProtocolTcp;
+ switch (protocol.value_or(kBestProtocol)) {
+ case ProtocolTcp:
+ return TCPSocket::CreatePair();
+#if LLDB_ENABLE_POSIX
+ case ProtocolUnixDomain:
+ case ProtocolUnixAbstract:
+ return DomainSocket::CreatePair();
+#endif
+ default:
+ return llvm::createStringError("Unsupported protocol");
+ }
+}
+
llvm::Expected<std::unique_ptr<Socket>>
Socket::TcpConnect(llvm::StringRef host_and_port) {
Log *log = GetLog(LLDBLog::Connection);
diff --git a/lldb/source/Host/common/TCPSocket.cpp b/lldb/source/Host/common/TCPSocket.cpp
index 3d0dea1c61dd6..34f249746149e 100644
--- a/lldb/source/Host/common/TCPSocket.cpp
+++ b/lldb/source/Host/common/TCPSocket.cpp
@@ -52,6 +52,34 @@ TCPSocket::TCPSocket(NativeSocket socket, bool should_close)
TCPSocket::~TCPSocket() { CloseListenSockets(); }
+llvm::Expected<
+ std::pair<std::unique_ptr<TCPSocket>, std::unique_ptr<TCPSocket>>>
+TCPSocket::CreatePair() {
+ auto listen_socket_up = std::make_unique<TCPSocket>(true);
+ if (Status error = listen_socket_up->Listen("localhost:0", 5); error.Fail())
+ return error.takeError();
+
+ std::string connect_address =
+ llvm::StringRef(listen_socket_up->GetListeningConnectionURI()[0])
+ .split("://")
+ .second.str();
+
+ auto connect_socket_up = std::make_unique<TCPSocket>(true);
+ if (Status error = connect_socket_up->Connect(connect_address); error.Fail())
+ return error.takeError();
+
+ // Connection has already been made above, so a short timeout is sufficient.
+ Socket *accept_socket;
+ if (Status error =
+ listen_socket_up->Accept(std::chrono::seconds(1), accept_socket);
+ error.Fail())
+ return error.takeError();
+
+ return std::make_pair(
+ std::move(connect_socket_up),
+ std::unique_ptr<TCPSocket>(static_cast<TCPSocket *>(accept_socket)));
+}
+
bool TCPSocket::IsValid() const {
return m_socket != kInvalidSocketValue || m_listen_sockets.size() != 0;
}
diff --git a/lldb/source/Host/posix/DomainSocket.cpp b/lldb/source/Host/posix/DomainSocket.cpp
index 4f76e0c16d4c7..0202dea45a8e1 100644
--- a/lldb/source/Host/posix/DomainSocket.cpp
+++ b/lldb/source/Host/posix/DomainSocket.cpp
@@ -13,9 +13,11 @@
#endif
#include "llvm/Support/Errno.h"
+#include "llvm/Support/Error.h"
#include "llvm/Support/FileSystem.h"
#include <cstddef>
+#include <fcntl.h>
#include <memory>
#include <sys/socket.h>
#include <sys/un.h>
@@ -76,6 +78,33 @@ DomainSocket::DomainSocket(SocketProtocol protocol, NativeSocket socket,
m_socket = socket;
}
+llvm::Expected<
+ std::pair<std::unique_ptr<DomainSocket>, std::unique_ptr<DomainSocket>>>
+DomainSocket::CreatePair() {
+ int sockets[2];
+ int type = SOCK_STREAM;
+#ifdef SOCK_CLOEXEC
+ type |= SOCK_CLOEXEC;
+#endif
+ if (socketpair(AF_UNIX, type, 0, sockets) == -1)
+ return llvm::errorCodeToError(llvm::errnoAsErrorCode());
+
+#ifndef SOCK_CLOEXEC
+ for (int s : sockets) {
+ int r = fcntl(s, F_SETFD, FD_CLOEXEC | fcntl(s, F_GETFD));
+ assert(r == 0);
+ (void)r;
+ }
+#endif
+
+ return std::make_pair(std::unique_ptr<DomainSocket>(
+ new DomainSocket(ProtocolUnixDomain, sockets[0],
+ /*should_close=*/true)),
+ std::unique_ptr<DomainSocket>(
+ new DomainSocket(ProtocolUnixDomain, sockets[1],
+ /*should_close=*/true)));
+}
+
Status DomainSocket::Connect(llvm::StringRef name) {
sockaddr_un saddr_un;
socklen_t saddr_un_len;
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
index 2aea7c6b781d7..590d78e98f9a0 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
@@ -1141,34 +1141,14 @@ void GDBRemoteCommunication::DumpHistory(Stream &strm) { m_history.Dump(strm); }
llvm::Error
GDBRemoteCommunication::ConnectLocally(GDBRemoteCommunication &client,
GDBRemoteCommunication &server) {
- const int backlog = 5;
- TCPSocket listen_socket(true);
- if (llvm::Error error =
- listen_socket.Listen("localhost:0", backlog).ToError())
- return error;
-
- llvm::SmallString<32> remote_addr;
- llvm::raw_svector_ostream(remote_addr)
- << "connect://localhost:" << listen_socket.GetLocalPortNumber();
-
- std::unique_ptr<ConnectionFileDescriptor> conn_up(
- new ConnectionFileDescriptor());
- Status status;
- if (conn_up->Connect(remote_addr, &status) != lldb::eConnectionStatusSuccess)
- return llvm::createStringError(llvm::inconvertibleErrorCode(),
- "Unable to connect: %s", status.AsCString());
-
- // The connection was already established above, so a short timeout is
- // sufficient.
- Socket *accept_socket = nullptr;
- if (Status accept_status =
- listen_socket.Accept(std::chrono::seconds(1), accept_socket);
- accept_status.Fail())
- return accept_status.takeError();
-
- client.SetConnection(std::move(conn_up));
- server.SetConnection(
- std::make_unique<ConnectionFileDescriptor>(accept_socket));
+ auto expected_socket_pair = Socket::CreatePair();
+ if (!expected_socket_pair)
+ return expected_socket_pair.takeError();
+
+ client.SetConnection(std::make_unique<ConnectionFileDescriptor>(
+ expected_socket_pair->first.release()));
+ server.SetConnection(std::make_unique<ConnectionFileDescriptor>(
+ expected_socket_pair->second.release()));
return llvm::Error::success();
}
diff --git a/lldb/unittests/Core/CommunicationTest.cpp b/lldb/unittests/Core/CommunicationTest.cpp
index df9ff089a0d73..369d1534ae32a 100644
--- a/lldb/unittests/Core/CommunicationTest.cpp
+++ b/lldb/unittests/Core/CommunicationTest.cpp
@@ -7,14 +7,14 @@
//===----------------------------------------------------------------------===//
#include "lldb/Core/Communication.h"
+#include "TestingSupport/SubsystemRAII.h"
#include "lldb/Core/ThreadedCommunication.h"
#include "lldb/Host/Config.h"
#include "lldb/Host/ConnectionFileDescriptor.h"
#include "lldb/Host/Pipe.h"
+#include "lldb/Host/Socket.h"
#include "llvm/Testing/Support/Error.h"
#include "gtest/gtest.h"
-#include "TestingSupport/Host/SocketTestUtilities.h"
-#include "TestingSupport/SubsystemRAII.h"
#include <chrono>
#include <thread>
@@ -31,15 +31,17 @@ class CommunicationTest : public testing::Test {
};
static void CommunicationReadTest(bool use_read_thread) {
- std::unique_ptr<TCPSocket> a, b;
- ASSERT_TRUE(CreateTCPConnectedSockets("localhost", &a, &b));
+ auto maybe_socket_pair = Socket::CreatePair();
+ ASSERT_THAT_EXPECTED(maybe_socket_pair, llvm::Succeeded());
+ Socket &a = *maybe_socket_pair->first;
size_t num_bytes = 4;
- ASSERT_THAT_ERROR(a->Write("test", num_bytes).ToError(), llvm::Succeeded());
+ ASSERT_THAT_ERROR(a.Write("test", num_bytes).ToError(), llvm::Succeeded());
ASSERT_EQ(num_bytes, 4U);
ThreadedCommunication comm("test");
- comm.SetConnection(std::make_unique<ConnectionFileDescriptor>(b.release()));
+ comm.SetConnection(std::make_unique<ConnectionFileDescriptor>(
+ maybe_socket_pair->second.release()));
comm.SetCloseOnEOF(true);
if (use_read_thread) {
@@ -73,7 +75,7 @@ static void CommunicationReadTest(bool use_read_thread) {
EXPECT_THAT_ERROR(error.ToError(), llvm::Failed());
// This read should return EOF.
- ASSERT_THAT_ERROR(a->Close().ToError(), llvm::Succeeded());
+ ASSERT_THAT_ERROR(a.Close().ToError(), llvm::Succeeded());
error.Clear();
EXPECT_EQ(
comm.Read(buf, sizeof(buf), std::chrono::seconds(5), status, &error), 0U);
@@ -118,17 +120,19 @@ TEST_F(CommunicationTest, ReadThread) {
}
TEST_F(CommunicationTest, SynchronizeWhileClosing) {
- std::unique_ptr<TCPSocket> a, b;
- ASSERT_TRUE(CreateTCPConnectedSockets("localhost", &a, &b));
+ auto maybe_socket_pair = Socket::CreatePair();
+ ASSERT_THAT_EXPECTED(maybe_socket_pair, llvm::Succeeded());
+ Socket &a = *maybe_socket_pair->first;
ThreadedCommunication comm("test");
- comm.SetConnection(std::make_unique<ConnectionFileDescriptor>(b.release()));
+ comm.SetConnection(std::make_unique<ConnectionFileDescriptor>(
+ maybe_socket_pair->second.release()));
comm.SetCloseOnEOF(true);
ASSERT_TRUE(comm.StartReadThread());
// Ensure that we can safely synchronize with the read thread while it is
// closing the read end (in response to us closing the write end).
- ASSERT_THAT_ERROR(a->Close().ToError(), llvm::Succeeded());
+ ASSERT_THAT_ERROR(a.Close().ToError(), llvm::Succeeded());
comm.SynchronizeWithReadThread();
ASSERT_TRUE(comm.StopReadThread());
diff --git a/lldb/unittests/Host/SocketTest.cpp b/lldb/unittests/Host/SocketTest.cpp
index 77366593f05f8..3630b63242707 100644
--- a/lldb/unittests/Host/SocketTest.cpp
+++ b/lldb/unittests/Host/SocketTest.cpp
@@ -74,6 +74,41 @@ TEST_F(SocketTest, DecodeHostAndPort) {
llvm::HasValue(Socket::HostAndPort{"abcd:12fg:AF58::1", 12345}));
}
+TEST_F(SocketTest, CreatePair) {
+ std::vector<std::optional<Socket::SocketProtocol>> functional_protocols = {
+ std::nullopt,
+ Socket::ProtocolTcp,
+#if LLDB_ENABLE_POSIX
+ Socket::ProtocolUnixDomain,
+ Socket::ProtocolUnixAbstract,
+#endif
+ };
+ for (auto p : functional_protocols) {
+ auto expected_socket_pair = Socket::CreatePair(p);
+ ASSERT_THAT_EXPECTED(expected_socket_pair, llvm::Succeeded());
+ Socket &a = *expected_socket_pair->first;
+ Socket &b = *expected_socket_pair->second;
+ size_t num_bytes = 1;
+ ASSERT_THAT_ERROR(a.Write("a", num_bytes).takeError(), llvm::Succeeded());
+ ASSERT_EQ(num_bytes, 1);
+ char c;
+ ASSERT_THAT_ERROR(b.Read(&c, num_bytes).takeError(), llvm::Succeeded());
+ ASSERT_EQ(num_bytes, 1);
+ ASSERT_EQ(c, 'a');
+ }
+
+ std::vector<Socket::SocketProtocol> erroring_protocols = {
+#if !LLDB_ENABLE_POSIX
+ Socket::ProtocolUnixDomain,
+ Socket::ProtocolUnixAbstract,
+#endif
+ };
+ for (auto p : erroring_protocols) {
+ ASSERT_THAT_EXPECTED(Socket::CreatePair(p),
+ llvm::FailedWithMessage("Unsupported protocol"));
+ }
+}
+
#if LLDB_ENABLE_POSIX
TEST_F(SocketTest, DomainListenConnectAccept) {
llvm::SmallString<64> Path;
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