core: use ProcLock for single-instance

Author: vaxerski

CMakeLists.txt

@@ -26,7 +26,7 @@ pkg_check_modules(
   hyprtoolkit
   pixman-1
   libdrm
-  hyprutils>=0.12.0
+  hyprutils>=0.14.1
   hyprwire
   icu-uc
   hyprlang
@@ -90,4 +90,4 @@ target_include_directories(hyprlauncher PRIVATE "./protocols")
 
 target_link_libraries(hyprlauncher PkgConfig::deps)
 
-install(TARGETS hyprlauncher)
+install(TARGETS hyprlauncher)

flake.lock

@@ -12,10 +12,15 @@
 #include "i18n/Engine.hpp"
 
 #include <iostream>
+#include <chrono>
+#include <cstdlib>
+#include <thread>
 
+#include <hyprutils/os/ProcLock.hpp>
 #include <hyprutils/string/ConstVarList.hpp>
 
 using namespace Hyprutils::String;
+using namespace Hyprutils::OS;
 
 static void printHelp() {
     std::cout << "Hyprlauncher usage: hyprlauncher [arg [...]].\n\nArguments:\n"
@@ -45,6 +50,18 @@ static std::vector<std::string> parseExplicitFromStdin() {
     return result;
 }
 
+static const char* procLockErrorString(CProcLock::eProcLockObtainingError error) {
+    switch (error) {
+        case CProcLock::eProcLockObtainingError::ALREADY_TAKEN: return "lock already taken by this process";
+        case CProcLock::eProcLockObtainingError::NO_ENVIRONMENT: return "XDG_RUNTIME_DIR is unset";
+        case CProcLock::eProcLockObtainingError::ALREADY_RUNNING: return "another instance is running";
+        case CProcLock::eProcLockObtainingError::PERMISSIONS_INSUFFICIENT: return "insufficient permissions for runtime lock";
+        case CProcLock::eProcLockObtainingError::UNKNOWN: return "unknown error";
+    }
+
+    return "unknown error";
+}
+
 int main(int argc, char** argv, char** envp) {
 
     bool                     openByDefault = true, dmenuMode = false, toggle = false;
@@ -89,12 +106,28 @@ int main(int argc, char** argv, char** envp) {
         }
     }
 
-    auto socket = makeShared<CClientIPCSocket>();
-
     if (dmenuMode)
         explicitOptions = parseExplicitFromStdin();
 
-    if (socket->m_connected) {
+    const auto WAYLAND_DISPLAY_ENV = getenv("WAYLAND_DISPLAY");
+    const auto WAYLAND_DISPLAY     = WAYLAND_DISPLAY_ENV ? std::string{WAYLAND_DISPLAY_ENV} : std::string{};
+
+    CProcLock  procLock{"hyprlauncher", {{"WAYLAND_DISPLAY", WAYLAND_DISPLAY}}};
+    const auto lockResult = procLock.obtain(CProcLock::eProcLockFlags::EXCLUSIVE);
+
+    if (!lockResult) {
+        if (lockResult.error() != CProcLock::eProcLockObtainingError::ALREADY_RUNNING) {
+            Debug::log(ERR, "Failed to obtain process lock: {}", procLockErrorString(lockResult.error()));
+            return 1;
+        }
+
+        SP<CClientIPCSocket> socket = makeShared<CClientIPCSocket>(WAYLAND_DISPLAY);
+
+        if (!socket->m_connected) {
+            Debug::log(ERR, "Another instance is running, but its IPC socket is unavailable (probably starting up)");
+            return 1;
+        }
+
         Debug::log(TRACE, "Active instance already, opening launcher.");
         if (!explicitOptions.empty())
             socket->sendOpenWithOptions(explicitOptions);
@@ -103,7 +136,11 @@ int main(int argc, char** argv, char** envp) {
         return 0;
     }
 
-    g_serverIPCSocket = makeUnique<CServerIPCSocket>();
+    g_serverIPCSocket = makeUnique<CServerIPCSocket>(WAYLAND_DISPLAY);
+    if (!g_serverIPCSocket->valid()) {
+        Debug::log(ERR, "Failed to open IPC server socket");
+        return 1;
+    }
 
     g_desktopFinder = makeUnique<CDesktopFinder>();
     g_unicodeFinder = makeUnique<CUnicodeFinder>();
@@ -117,8 +154,6 @@ int main(int argc, char** argv, char** envp) {
     g_ipcFinder->init();
     g_fontFinder->init();
 
-    socket.reset();
-
     I18n::initEngine();
 
     if (!explicitOptions.empty()) {

src/main.cpp

@@ -1,18 +1,16 @@
 #include "ClientSocket.hpp"
+#include "SocketPath.hpp"
 
-#include <cstdlib>
 #include <print>
 
-constexpr const char*             SOCKET_NAME = ".hyprlauncher.sock";
 static SP<CCHyprlauncherCoreImpl> g_coreImpl;
 
-CClientIPCSocket::CClientIPCSocket() {
-    const auto RTDIR = getenv("XDG_RUNTIME_DIR");
-
-    if (!RTDIR)
+CClientIPCSocket::CClientIPCSocket(const std::string& waylandDisplay) {
+    const auto socketPath = socketPathForDisplay(waylandDisplay);
+    if (!socketPath)
         return;
 
-    m_socketPath = RTDIR + std::string{"/"} + SOCKET_NAME;
+    m_socketPath = *socketPath;
 
     m_socket = Hyprwire::IClientSocket::open(m_socketPath);
 

src/socket/ClientSocket.cpp

@@ -7,7 +7,7 @@
 
 class CClientIPCSocket {
   public:
-    CClientIPCSocket();
+    CClientIPCSocket(const std::string& waylandDisplay);
     ~CClientIPCSocket() = default;
 
     bool m_connected = false;

src/socket/ClientSocket.hpp

@@ -1,22 +1,19 @@
 #include "ServerSocket.hpp"
+#include "SocketPath.hpp"
 #include "../ui/UI.hpp"
 #include "../query/QueryProcessor.hpp"
 #include "../finders/ipc/IPCFinder.hpp"
 
-#include <cstdlib>
 #include <filesystem>
 
-constexpr const char*            SOCKET_NAME = ".hyprlauncher.sock";
-
 static SP<CHyprlauncherCoreImpl> g_coreImpl;
 
-CServerIPCSocket::CServerIPCSocket() {
-    const auto RTDIR = getenv("XDG_RUNTIME_DIR");
-
-    if (!RTDIR)
+CServerIPCSocket::CServerIPCSocket(const std::string& waylandDisplay) {
+    const auto socketPath = socketPathForDisplay(waylandDisplay);
+    if (!socketPath)
         return;
 
-    m_socketPath = RTDIR + std::string{"/"} + SOCKET_NAME;
+    m_socketPath = *socketPath;
 
     std::error_code ec;
     std::filesystem::remove(m_socketPath, ec);
@@ -49,6 +46,10 @@ CServerIPCSocket::CServerIPCSocket() {
     m_socket->addImplementation(g_coreImpl);
 }
 
+bool CServerIPCSocket::valid() const {
+    return !!m_socket;
+}
+
 void CServerIPCSocket::setOpenState(uint32_t state) {
     switch (state) {
         case 0: g_ui->setWindowOpen(!g_ui->windowOpen()); break;

src/socket/ServerSocket.cpp

@@ -7,9 +7,11 @@
 
 class CServerIPCSocket {
   public:
-    CServerIPCSocket();
+    CServerIPCSocket(const std::string& waylandDisplay);
     ~CServerIPCSocket() = default;
 
+    bool valid() const;
+
     void sendOpenState(bool open);
     void sendSelectionMade(const std::string& s);
 

src/socket/ServerSocket.hpp

@@ -0,0 +1,19 @@
+#include "SocketPath.hpp"
+
+#include <cstdint>
+#include <cstdlib>
+#include <format>
+
+std::optional<std::string> socketPathForDisplay(std::string_view waylandDisplay) {
+    const auto runtimeDir = getenv("XDG_RUNTIME_DIR");
+    if (!runtimeDir || runtimeDir[0] == '\0')
+        return std::nullopt;
+
+    uint64_t displayHash = 14695981039346656037ULL;
+    for (const unsigned char c : waylandDisplay) {
+        displayHash ^= c;
+        displayHash *= 1099511628211ULL;
+    }
+
+    return std::format("{}/.hyprlauncher-{:016x}.sock", runtimeDir, displayHash);
+}

src/socket/SocketPath.cpp

@@ -0,0 +1,7 @@
+#pragma once
+
+#include <optional>
+#include <string>
+#include <string_view>
+
+std::optional<std::string> socketPathForDisplay(std::string_view waylandDisplay);