From 531572b411a4a311cb38bcf09a2c95559ef068aa Mon Sep 17 00:00:00 2001
From: Liam <byteslice@airmail.cc>
Date: Sat, 26 Aug 2023 18:18:13 -0400
Subject: internal_network: cancel pending socket operations on application
 process termination

---
 src/core/core.cpp                     |  2 +
 src/core/internal_network/network.cpp | 86 +++++++++++++++++++++++++++++++++--
 src/core/internal_network/network.h   |  3 ++
 3 files changed, 88 insertions(+), 3 deletions(-)

diff --git a/src/core/core.cpp b/src/core/core.cpp
index 2f67e60a9..9c5246a56 100644
--- a/src/core/core.cpp
+++ b/src/core/core.cpp
@@ -404,6 +404,7 @@ struct System::Impl {
             gpu_core->NotifyShutdown();
         }
 
+        Network::CancelPendingSocketOperations();
         kernel.SuspendApplication(true);
         if (services) {
             services->KillNVNFlinger();
@@ -425,6 +426,7 @@ struct System::Impl {
         debugger.reset();
         kernel.Shutdown();
         memory.Reset();
+        Network::RestartSocketOperations();
 
         if (auto room_member = room_network.GetRoomMember().lock()) {
             Network::GameInfo game_info{};
diff --git a/src/core/internal_network/network.cpp b/src/core/internal_network/network.cpp
index 5d28300e6..ef5e5d013 100644
--- a/src/core/internal_network/network.cpp
+++ b/src/core/internal_network/network.cpp
@@ -48,15 +48,32 @@ enum class CallType {
 
 using socklen_t = int;
 
+SOCKET interrupt_socket = static_cast<SOCKET>(-1);
+
+void InterruptSocketOperations() {
+    closesocket(interrupt_socket);
+}
+
+void AcknowledgeInterrupt() {
+    interrupt_socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+}
+
 void Initialize() {
     WSADATA wsa_data;
     (void)WSAStartup(MAKEWORD(2, 2), &wsa_data);
+
+    AcknowledgeInterrupt();
 }
 
 void Finalize() {
+    InterruptSocketOperations();
     WSACleanup();
 }
 
+SOCKET GetInterruptSocket() {
+    return interrupt_socket;
+}
+
 sockaddr TranslateFromSockAddrIn(SockAddrIn input) {
     sockaddr_in result;
 
@@ -157,9 +174,39 @@ constexpr int SD_RECEIVE = SHUT_RD;
 constexpr int SD_SEND = SHUT_WR;
 constexpr int SD_BOTH = SHUT_RDWR;
 
-void Initialize() {}
+int interrupt_pipe_fd[2] = {-1, -1};
+
+void Initialize() {
+    if (pipe(interrupt_pipe_fd) != 0) {
+        LOG_ERROR(Network, "Failed to create interrupt pipe!");
+    }
+    int flags = fcntl(interrupt_pipe_fd[0], F_GETFL);
+    ASSERT_MSG(fcntl(interrupt_pipe_fd[0], F_SETFL, flags | O_NONBLOCK) == 0,
+               "Failed to set nonblocking state for interrupt pipe");
+}
+
+void Finalize() {
+    if (interrupt_pipe_fd[0] >= 0) {
+        close(interrupt_pipe_fd[0]);
+    }
+    if (interrupt_pipe_fd[1] >= 0) {
+        close(interrupt_pipe_fd[1]);
+    }
+}
+
+void InterruptSocketOperations() {
+    u8 value = 0;
+    ASSERT(write(interrupt_pipe_fd[1], &value, sizeof(value)) == 1);
+}
 
-void Finalize() {}
+void AcknowledgeInterrupt() {
+    u8 value = 0;
+    read(interrupt_pipe_fd[0], &value, sizeof(value));
+}
+
+SOCKET GetInterruptSocket() {
+    return interrupt_pipe_fd[0];
+}
 
 sockaddr TranslateFromSockAddrIn(SockAddrIn input) {
     sockaddr_in result;
@@ -490,6 +537,14 @@ NetworkInstance::~NetworkInstance() {
     Finalize();
 }
 
+void CancelPendingSocketOperations() {
+    InterruptSocketOperations();
+}
+
+void RestartSocketOperations() {
+    AcknowledgeInterrupt();
+}
+
 std::optional<IPv4Address> GetHostIPv4Address() {
     const auto network_interface = Network::GetSelectedNetworkInterface();
     if (!network_interface.has_value()) {
@@ -560,7 +615,14 @@ std::pair<s32, Errno> Poll(std::vector<PollFD>& pollfds, s32 timeout) {
         return result;
     });
 
-    const int result = WSAPoll(host_pollfds.data(), static_cast<ULONG>(num), timeout);
+    host_pollfds.push_back(WSAPOLLFD{
+        .fd = GetInterruptSocket(),
+        .events = POLLIN,
+        .revents = 0,
+    });
+
+    const int result =
+        WSAPoll(host_pollfds.data(), static_cast<ULONG>(host_pollfds.size()), timeout);
     if (result == 0) {
         ASSERT(std::all_of(host_pollfds.begin(), host_pollfds.end(),
                            [](WSAPOLLFD fd) { return fd.revents == 0; }));
@@ -627,6 +689,24 @@ Errno Socket::Initialize(Domain domain, Type type, Protocol protocol) {
 std::pair<SocketBase::AcceptResult, Errno> Socket::Accept() {
     sockaddr_in addr;
     socklen_t addrlen = sizeof(addr);
+
+    std::vector<WSAPOLLFD> host_pollfds{
+        WSAPOLLFD{fd, POLLIN, 0},
+        WSAPOLLFD{GetInterruptSocket(), POLLIN, 0},
+    };
+
+    while (true) {
+        const int pollres =
+            WSAPoll(host_pollfds.data(), static_cast<ULONG>(host_pollfds.size()), -1);
+        if (host_pollfds[1].revents != 0) {
+            // Interrupt signaled before a client could be accepted, break
+            return {AcceptResult{}, Errno::AGAIN};
+        }
+        if (pollres > 0) {
+            break;
+        }
+    }
+
     const SOCKET new_socket = accept(fd, reinterpret_cast<sockaddr*>(&addr), &addrlen);
 
     if (new_socket == INVALID_SOCKET) {
diff --git a/src/core/internal_network/network.h b/src/core/internal_network/network.h
index c7e20ae34..b7b7d773a 100644
--- a/src/core/internal_network/network.h
+++ b/src/core/internal_network/network.h
@@ -96,6 +96,9 @@ public:
     ~NetworkInstance();
 };
 
+void CancelPendingSocketOperations();
+void RestartSocketOperations();
+
 #ifdef _WIN32
 constexpr IPv4Address TranslateIPv4(in_addr addr) {
     auto& bytes = addr.S_un.S_un_b;
-- 
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