Merge pull request #4891 from khaneliman/bugfix/stab-003-test-001-hyprland-ipc

fix(hyprland-ipc): harden fd lifecycle and listener loop

include/modules/hyprland/backend.hpp

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <atomic>
 #include <filesystem>
 #include <list>
 #include <mutex>
@@ -43,10 +44,11 @@ class IPC {
 
   std::thread ipcThread_;
   std::mutex callbackMutex_;
+  std::mutex socketMutex_;
   util::JsonParser parser_;
   std::list<std::pair<std::string, EventHandler*>> callbacks_;
-  int socketfd_;  // the hyprland socket file descriptor
-  pid_t socketOwnerPid_;
-  bool running_ = true;  // the ipcThread will stop running when this is false
+  int socketfd_ = -1;  // the hyprland socket file descriptor
+  pid_t socketOwnerPid_ = -1;
+  std::atomic<bool> running_ = true;  // the ipcThread will stop running when this is false
 };
 };  // namespace waybar::modules::hyprland

include/modules/sway/ipc/client.hpp

@@ -14,6 +14,7 @@
 #include "ipc.hpp"
 #include "util/SafeSignal.hpp"
 #include "util/sleeper_thread.hpp"
+#include "util/scoped_fd.hpp"
 
 namespace waybar::modules::sway {
 
@@ -45,8 +46,8 @@ class Ipc {
   struct ipc_response send(int fd, uint32_t type, const std::string& payload = "");
   struct ipc_response recv(int fd);
 
-  int fd_;
-  int fd_event_;
+  util::ScopedFd fd_;
+  util::ScopedFd fd_event_;
   std::mutex mutex_;
   util::SleeperThread thread_;
 };

include/modules/wayfire/backend.hpp

@@ -12,6 +12,8 @@
 #include <unordered_map>
 #include <utility>
 
+#include "util/scoped_fd.hpp"
+
 namespace waybar::modules::wayfire {
 
 using EventHandler = std::function<void(const std::string& event)>;
@@ -71,23 +73,7 @@ struct State {
   auto update_view(const Json::Value& view) -> void;
 };
 
-struct Sock {
-  int fd;
-
-  Sock(int fd) : fd{fd} {}
-  ~Sock() { close(fd); }
-  Sock(const Sock&) = delete;
-  auto operator=(const Sock&) = delete;
-  Sock(Sock&& rhs) noexcept {
-    fd = rhs.fd;
-    rhs.fd = -1;
-  }
-  auto& operator=(Sock&& rhs) noexcept {
-    fd = rhs.fd;
-    rhs.fd = -1;
-    return *this;
-  }
-};
+using Sock = util::ScopedFd;
 
 class IPC : public std::enable_shared_from_this<IPC> {
   static std::weak_ptr<IPC> instance;

include/util/scoped_fd.hpp

@@ -0,0 +1,54 @@
+#pragma once
+
+#include <unistd.h>
+
+namespace waybar::util {
+
+class ScopedFd {
+ public:
+  explicit ScopedFd(int fd = -1) : fd_(fd) {}
+  ~ScopedFd() {
+    if (fd_ != -1) {
+      close(fd_);
+    }
+  }
+
+  // ScopedFd is non-copyable
+  ScopedFd(const ScopedFd&) = delete;
+  ScopedFd& operator=(const ScopedFd&) = delete;
+
+  // ScopedFd is moveable
+  ScopedFd(ScopedFd&& other) noexcept : fd_(other.fd_) { other.fd_ = -1; }
+  ScopedFd& operator=(ScopedFd&& other) noexcept {
+    if (this != &other) {
+      if (fd_ != -1) {
+        close(fd_);
+      }
+      fd_ = other.fd_;
+      other.fd_ = -1;
+    }
+    return *this;
+  }
+
+  int get() const { return fd_; }
+
+  operator int() const { return fd_; }
+
+  void reset(int fd = -1) {
+    if (fd_ != -1) {
+      close(fd_);
+    }
+    fd_ = fd;
+  }
+
+  int release() {
+    int fd = fd_;
+    fd_ = -1;
+    return fd;
+  }
+
+ private:
+  int fd_;
+};
+
+}  // namespace waybar::util

src/modules/hyprland/backend.cpp

@@ -9,9 +9,14 @@
 #include <sys/un.h>
 #include <unistd.h>
 
+#include <array>
+#include <cerrno>
+#include <cstring>
 #include <filesystem>
 #include <string>
 
+#include "util/scoped_fd.hpp"
+
 namespace waybar::modules::hyprland {
 
 std::filesystem::path IPC::socketFolder_;
@@ -45,8 +50,8 @@ std::filesystem::path IPC::getSocketFolder(const char* instanceSig) {
 
 IPC::IPC() {
   // will start IPC and relay events to parseIPC
-  ipcThread_ = std::thread([this]() { socketListener(); });
   socketOwnerPid_ = getpid();
+  ipcThread_ = std::thread([this]() { socketListener(); });
 }
 
 IPC::~IPC() {
@@ -54,20 +59,21 @@ IPC::~IPC() {
   // failed exec()) exits.
   if (getpid() != socketOwnerPid_) return;
 
-  running_ = false;
+  running_.store(false, std::memory_order_relaxed);
   spdlog::info("Hyprland IPC stopping...");
+  {
+    std::lock_guard<std::mutex> lock(socketMutex_);
     if (socketfd_ != -1) {
       spdlog::trace("Shutting down socket");
-    if (shutdown(socketfd_, SHUT_RDWR) == -1) {
+      if (shutdown(socketfd_, SHUT_RDWR) == -1 && errno != ENOTCONN) {
         spdlog::error("Hyprland IPC: Couldn't shutdown socket");
       }
-    spdlog::trace("Closing socket");
-    if (close(socketfd_) == -1) {
-      spdlog::error("Hyprland IPC: Couldn't close socket");
     }
   }
+  if (ipcThread_.joinable()) {
     ipcThread_.join();
   }
+}
 
 IPC& IPC::inst() {
   static IPC ipc;
@@ -86,9 +92,9 @@ void IPC::socketListener() {
   spdlog::info("Hyprland IPC starting");
 
   struct sockaddr_un addr;
-  socketfd_ = socket(AF_UNIX, SOCK_STREAM, 0);
+  const int socketfd = socket(AF_UNIX, SOCK_STREAM, 0);
 
-  if (socketfd_ == -1) {
+  if (socketfd == -1) {
     spdlog::error("Hyprland IPC: socketfd failed");
     return;
   }
@@ -102,27 +108,48 @@ void IPC::socketListener() {
 
   int l = sizeof(struct sockaddr_un);
 
-  if (connect(socketfd_, (struct sockaddr*)&addr, l) == -1) {
-    spdlog::error("Hyprland IPC: Unable to connect?");
+  if (connect(socketfd, (struct sockaddr*)&addr, l) == -1) {
+    spdlog::error("Hyprland IPC: Unable to connect? {}", std::strerror(errno));
+    close(socketfd);
     return;
   }
-  auto* file = fdopen(socketfd_, "r");
-  if (file == nullptr) {
-    spdlog::error("Hyprland IPC: Couldn't open file descriptor");
-    return;
+
+  {
+    std::lock_guard<std::mutex> lock(socketMutex_);
+    socketfd_ = socketfd;
   }
-  while (running_) {
+
+  std::string pending;
+  while (running_.load(std::memory_order_relaxed)) {
     std::array<char, 1024> buffer;  // Hyprland socket2 events are max 1024 bytes
+    const ssize_t bytes_read = read(socketfd, buffer.data(), buffer.size());
 
-    auto* receivedCharPtr = fgets(buffer.data(), buffer.size(), file);
+    if (bytes_read == 0) {
+      if (running_.load(std::memory_order_relaxed)) {
+        spdlog::warn("Hyprland IPC: Socket closed by peer");
+      }
+      break;
+    }
 
-    if (receivedCharPtr == nullptr) {
-      std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    if (bytes_read < 0) {
+      if (errno == EINTR) {
         continue;
       }
+      if (!running_.load(std::memory_order_relaxed)) {
+        break;
+      }
+      spdlog::error("Hyprland IPC: read failed: {}", std::strerror(errno));
+      break;
+    }
 
-    std::string messageReceived(buffer.data());
-    messageReceived = messageReceived.substr(0, messageReceived.find_first_of('\n'));
+    pending.append(buffer.data(), static_cast<std::size_t>(bytes_read));
+    for (auto newline_pos = pending.find('\n'); newline_pos != std::string::npos;
+         newline_pos = pending.find('\n')) {
+      std::string messageReceived = pending.substr(0, newline_pos);
+      pending.erase(0, newline_pos + 1);
+      if (messageReceived.empty()) {
+        continue;
+      }
       spdlog::debug("hyprland IPC received {}", messageReceived);
 
       try {
@@ -132,8 +159,16 @@ void IPC::socketListener() {
       } catch (...) {
         throw;
       }
-
-    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    }
+  }
+  {
+    std::lock_guard<std::mutex> lock(socketMutex_);
+    if (socketfd_ != -1) {
+      if (close(socketfd_) == -1) {
+        spdlog::error("Hyprland IPC: Couldn't close socket");
+      }
+      socketfd_ = -1;
+    }
   }
   spdlog::debug("Hyprland IPC stopped");
 }
@@ -178,7 +213,7 @@ void IPC::unregisterForIPC(EventHandler* ev_handler) {
 std::string IPC::getSocket1Reply(const std::string& rq) {
   // basically hyprctl
 
-  const auto serverSocket = socket(AF_UNIX, SOCK_STREAM, 0);
+  util::ScopedFd serverSocket(socket(AF_UNIX, SOCK_STREAM, 0));
 
   if (serverSocket < 0) {
     throw std::runtime_error("Hyprland IPC: Couldn't open a socket (1)");
@@ -223,13 +258,11 @@ std::string IPC::getSocket1Reply(const std::string& rq) {
 
     if (sizeWritten < 0) {
       spdlog::error("Hyprland IPC: Couldn't read (5)");
-      close(serverSocket);
       return "";
     }
     response.append(buffer.data(), sizeWritten);
   } while (sizeWritten > 0);
 
-  close(serverSocket);
   return response;
 }
 

src/modules/niri/backend.cpp

@@ -13,6 +13,7 @@
 #include <string>
 #include <thread>
 
+#include "util/scoped_fd.hpp"
 #include "giomm/datainputstream.h"
 #include "giomm/dataoutputstream.h"
 #include "giomm/unixinputstream.h"
@@ -30,7 +31,7 @@ int IPC::connectToSocket() {
   }
 
   struct sockaddr_un addr;
-  int socketfd = socket(AF_UNIX, SOCK_STREAM, 0);
+  util::ScopedFd socketfd(socket(AF_UNIX, SOCK_STREAM, 0));
 
   if (socketfd == -1) {
     throw std::runtime_error("socketfd failed");
@@ -45,11 +46,10 @@ int IPC::connectToSocket() {
   int l = sizeof(struct sockaddr_un);
 
   if (connect(socketfd, (struct sockaddr*)&addr, l) == -1) {
-    close(socketfd);
     throw std::runtime_error("unable to connect");
   }
 
-  return socketfd;
+  return socketfd.release();
 }
 
 void IPC::startIPC() {
@@ -235,7 +235,7 @@ void IPC::unregisterForIPC(EventHandler* ev_handler) {
 }
 
 Json::Value IPC::send(const Json::Value& request) {
-  int socketfd = connectToSocket();
+  util::ScopedFd socketfd(connectToSocket());
 
   auto unix_istream = Gio::UnixInputStream::create(socketfd, true);
   auto unix_ostream = Gio::UnixOutputStream::create(socketfd, false);

src/modules/sway/ipc/client.cpp

@@ -9,8 +9,8 @@ namespace waybar::modules::sway {
 
 Ipc::Ipc() {
   const std::string& socketPath = getSocketPath();
-  fd_ = open(socketPath);
-  fd_event_ = open(socketPath);
+  fd_ = util::ScopedFd(open(socketPath));
+  fd_event_ = util::ScopedFd(open(socketPath));
 }
 
 Ipc::~Ipc() {
@@ -21,15 +21,11 @@ Ipc::~Ipc() {
     if (write(fd_, "close-sway-ipc", 14) == -1) {
       spdlog::error("Failed to close sway IPC");
     }
-    close(fd_);
-    fd_ = -1;
   }
   if (fd_event_ > 0) {
     if (write(fd_event_, "close-sway-ipc", 14) == -1) {
       spdlog::error("Failed to close sway IPC event handler");
     }
-    close(fd_event_);
-    fd_event_ = -1;
   }
 }
 
@@ -64,7 +60,7 @@ const std::string Ipc::getSocketPath() const {
 }
 
 int Ipc::open(const std::string& socketPath) const {
-  int32_t fd = socket(AF_UNIX, SOCK_STREAM, 0);
+  util::ScopedFd fd(socket(AF_UNIX, SOCK_STREAM, 0));
   if (fd == -1) {
     throw std::runtime_error("Unable to open Unix socket");
   }
@@ -78,7 +74,7 @@ int Ipc::open(const std::string& socketPath) const {
   if (::connect(fd, reinterpret_cast<struct sockaddr*>(&addr), l) == -1) {
     throw std::runtime_error("Unable to connect to Sway");
   }
-  return fd;
+  return fd.release();
 }
 
 struct Ipc::ipc_response Ipc::recv(int fd) {

src/modules/wayfire/backend.cpp

@@ -27,14 +27,14 @@ inline auto byteswap(uint32_t x) -> uint32_t {
 auto pack_and_write(Sock& sock, std::string&& buf) -> void {
   uint32_t len = buf.size();
   if constexpr (std::endian::native != std::endian::little) len = byteswap(len);
-  (void)write(sock.fd, &len, 4);
-  (void)write(sock.fd, buf.data(), buf.size());
+  (void)write(sock, &len, 4);
+  (void)write(sock, buf.data(), buf.size());
 }
 
 auto read_exact(Sock& sock, size_t n) -> std::string {
   auto buf = std::string(n, 0);
   for (size_t i = 0; i < n;) {
-    auto r = read(sock.fd, &buf[i], n - i);
+    auto r = read(sock, &buf[i], n - i);
     if (r <= 0) {
       throw std::runtime_error("Wayfire IPC: read failed");
     }
@@ -111,7 +111,7 @@ auto IPC::connect() -> Sock {
     throw std::runtime_error{"Wayfire IPC: ipc not available"};
   }
 
-  auto sock = socket(AF_UNIX, SOCK_STREAM, 0);
+  util::ScopedFd sock(socket(AF_UNIX, SOCK_STREAM, 0));
   if (sock == -1) {
     throw std::runtime_error{"Wayfire IPC: socket() failed"};
   }
@@ -121,11 +121,10 @@ auto IPC::connect() -> Sock {
   addr.sun_path[sizeof(addr.sun_path) - 1] = 0;
 
   if (::connect(sock, (const sockaddr*)&addr, sizeof(addr)) == -1) {
-    close(sock);
     throw std::runtime_error{"Wayfire IPC: connect() failed"};
   }
 
-  return {sock};
+  return sock;
 }
 
 auto IPC::receive(Sock& sock) -> Json::Value {

test/hyprland/backend.cpp

@@ -4,56 +4,114 @@
 #include <catch2/catch.hpp>
 #endif
 
-#include "fixtures/IPCTestFixture.hpp"
+#include <system_error>
+
+#include "modules/hyprland/backend.hpp"
 
 namespace fs = std::filesystem;
 namespace hyprland = waybar::modules::hyprland;
 
-TEST_CASE_METHOD(IPCTestFixture, "XDGRuntimeDirExists", "[getSocketFolder]") {
+namespace {
+class IPCTestHelper : public hyprland::IPC {
+ public:
+  static void resetSocketFolder() { socketFolder_.clear(); }
+};
+
+std::size_t countOpenFds() {
+#if defined(__linux__)
+  std::size_t count = 0;
+  for (const auto& _ : fs::directory_iterator("/proc/self/fd")) {
+    (void)_;
+    ++count;
+  }
+  return count;
+#else
+  return 0;
+#endif
+}
+}  // namespace
+
+TEST_CASE("XDGRuntimeDirExists", "[getSocketFolder]") {
   // Test case: XDG_RUNTIME_DIR exists and contains "hypr" directory
   // Arrange
-  tempDir = fs::temp_directory_path() / "hypr_test/run/user/1000";
+  constexpr auto instanceSig = "instance_sig";
+  const fs::path tempDir = fs::temp_directory_path() / "hypr_test/run/user/1000";
+  std::error_code ec;
+  fs::remove_all(tempDir, ec);
   fs::path expectedPath = tempDir / "hypr" / instanceSig;
-  fs::create_directories(tempDir / "hypr" / instanceSig);
+  fs::create_directories(expectedPath);
   setenv("XDG_RUNTIME_DIR", tempDir.c_str(), 1);
+  IPCTestHelper::resetSocketFolder();
 
   // Act
-  fs::path actualPath = getSocketFolder(instanceSig);
+  fs::path actualPath = hyprland::IPC::getSocketFolder(instanceSig);
 
   // Assert expected result
   REQUIRE(actualPath == expectedPath);
+  fs::remove_all(tempDir, ec);
 }
 
-TEST_CASE_METHOD(IPCTestFixture, "XDGRuntimeDirDoesNotExist", "[getSocketFolder]") {
+TEST_CASE("XDGRuntimeDirDoesNotExist", "[getSocketFolder]") {
   // Test case: XDG_RUNTIME_DIR does not exist
   // Arrange
+  constexpr auto instanceSig = "instance_sig";
   unsetenv("XDG_RUNTIME_DIR");
   fs::path expectedPath = fs::path("/tmp") / "hypr" / instanceSig;
+  IPCTestHelper::resetSocketFolder();
 
   // Act
-  fs::path actualPath = getSocketFolder(instanceSig);
+  fs::path actualPath = hyprland::IPC::getSocketFolder(instanceSig);
 
   // Assert expected result
   REQUIRE(actualPath == expectedPath);
 }
 
-TEST_CASE_METHOD(IPCTestFixture, "XDGRuntimeDirExistsNoHyprDir", "[getSocketFolder]") {
+TEST_CASE("XDGRuntimeDirExistsNoHyprDir", "[getSocketFolder]") {
   // Test case: XDG_RUNTIME_DIR exists but does not contain "hypr" directory
   // Arrange
+  constexpr auto instanceSig = "instance_sig";
   fs::path tempDir = fs::temp_directory_path() / "hypr_test/run/user/1000";
+  std::error_code ec;
+  fs::remove_all(tempDir, ec);
   fs::create_directories(tempDir);
   setenv("XDG_RUNTIME_DIR", tempDir.c_str(), 1);
   fs::path expectedPath = fs::path("/tmp") / "hypr" / instanceSig;
+  IPCTestHelper::resetSocketFolder();
 
   // Act
-  fs::path actualPath = getSocketFolder(instanceSig);
+  fs::path actualPath = hyprland::IPC::getSocketFolder(instanceSig);
 
   // Assert expected result
   REQUIRE(actualPath == expectedPath);
+  fs::remove_all(tempDir, ec);
 }
 
-TEST_CASE_METHOD(IPCTestFixture, "getSocket1Reply throws on no socket", "[getSocket1Reply]") {
+TEST_CASE("getSocket1Reply throws on no socket", "[getSocket1Reply]") {
+  unsetenv("HYPRLAND_INSTANCE_SIGNATURE");
+  IPCTestHelper::resetSocketFolder();
   std::string request = "test_request";
 
-  CHECK_THROWS(getSocket1Reply(request));
+  CHECK_THROWS(hyprland::IPC::getSocket1Reply(request));
 }
+
+#if defined(__linux__)
+TEST_CASE("getSocket1Reply failure paths do not leak fds", "[getSocket1Reply][fd-leak]") {
+  const auto baseline = countOpenFds();
+
+  unsetenv("HYPRLAND_INSTANCE_SIGNATURE");
+  for (int i = 0; i < 16; ++i) {
+    IPCTestHelper::resetSocketFolder();
+    CHECK_THROWS(hyprland::IPC::getSocket1Reply("test_request"));
+  }
+  const auto after_missing_signature = countOpenFds();
+  REQUIRE(after_missing_signature == baseline);
+
+  setenv("HYPRLAND_INSTANCE_SIGNATURE", "definitely-not-running", 1);
+  for (int i = 0; i < 16; ++i) {
+    IPCTestHelper::resetSocketFolder();
+    CHECK_THROWS(hyprland::IPC::getSocket1Reply("test_request"));
+  }
+  const auto after_connect_failures = countOpenFds();
+  REQUIRE(after_connect_failures == baseline);
+}
+#endif

test/hyprland/fixtures/IPCTestFixture.hpp

@@ -1,25 +0,0 @@
-#include "modules/hyprland/backend.hpp"
-
-namespace fs = std::filesystem;
-namespace hyprland = waybar::modules::hyprland;
-
-class IPCTestFixture : public hyprland::IPC {
- public:
-  IPCTestFixture() : IPC() { IPC::socketFolder_ = ""; }
-  ~IPCTestFixture() { fs::remove_all(tempDir); }
-
- protected:
-  const char* instanceSig = "instance_sig";
-  fs::path tempDir = fs::temp_directory_path() / "hypr_test";
-
- private:
-};
-
-class IPCMock : public IPCTestFixture {
- public:
-  // Mock getSocket1Reply to return an empty string
-  static std::string getSocket1Reply(const std::string& rq) { return ""; }
-
- protected:
-  const char* instanceSig = "instance_sig";
-};