LibCore: Make LocalServer::take_over_from_system_server() return ErrorOr

This allows us to use TRY() or MUST() when calling it.

Userland/Libraries/LibCore/LocalServer.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -7,6 +7,7 @@
 #include <LibCore/LocalServer.h>
 #include <LibCore/LocalSocket.h>
 #include <LibCore/Notifier.h>
+#include <LibCore/System.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <sys/socket.h>
@@ -30,10 +31,10 @@ LocalServer::~LocalServer()
         ::close(m_fd);
 }
 
-bool LocalServer::take_over_from_system_server(String const& socket_path)
+ErrorOr<void> LocalServer::take_over_from_system_server(String const& socket_path)
 {
     if (m_listening)
-        return false;
+        return Error::from_string_literal("Core::LocalServer: Can't perform socket takeover when already listening"sv);
 
     if (!LocalSocket::s_overtaken_sockets_parsed)
         LocalSocket::parse_sockets_from_system_server();
@@ -51,32 +52,27 @@ bool LocalServer::take_over_from_system_server(String const& socket_path)
         }
     }
 
-    if (fd >= 0) {
-        // Sanity check: it has to be a socket.
-        struct stat stat;
-        int rc = fstat(fd, &stat);
-        if (rc == 0 && S_ISSOCK(stat.st_mode)) {
-            // The SystemServer has passed us the socket, so use that instead of
-            // creating our own.
-            m_fd = fd;
-            // It had to be !CLOEXEC for obvious reasons, but we
-            // don't need it to be !CLOEXEC anymore, so set the
-            // CLOEXEC flag now.
-            fcntl(m_fd, F_SETFD, FD_CLOEXEC);
-
-            m_listening = true;
-            setup_notifier();
-            return true;
-        } else {
-            if (rc != 0)
-                perror("fstat");
-            dbgln("It's not a socket, what the heck??");
-        }
-    }
+    if (fd < 0)
+        return Error::from_string_literal("Core::LocalServer: No file descriptor for socket takeover"sv);
+
+    // Sanity check: it has to be a socket.
+    auto stat = TRY(Core::System::fstat(fd));
 
-    dbgln("Failed to take the socket over from SystemServer");
+    if (!S_ISSOCK(stat.st_mode))
+        return Error::from_string_literal("Core::LocalServer: Attempted socket takeover with non-socket file descriptor"sv);
 
-    return false;
+    // It had to be !CLOEXEC for obvious reasons, but we
+    // don't need it to be !CLOEXEC anymore, so set the
+    // CLOEXEC flag now.
+    TRY(Core::System::fcntl(fd, F_SETFD, FD_CLOEXEC));
+
+    // The SystemServer has passed us the socket, so use that instead of
+    // creating our own.
+    m_fd = fd;
+
+    m_listening = true;
+    setup_notifier();
+    return {};
 }
 
 void LocalServer::setup_notifier()

Userland/Libraries/LibCore/LocalServer.h

@@ -16,7 +16,7 @@ class LocalServer : public Object {
 public:
     virtual ~LocalServer() override;
 
-    bool take_over_from_system_server(String const& path = String());
+    ErrorOr<void> take_over_from_system_server(String const& path = String());
     bool is_listening() const { return m_listening; }
     bool listen(const String& address);
 

Userland/Libraries/LibWeb/CSS/MediaQueryList.cpp

@@ -44,9 +44,12 @@ bool MediaQueryList::matches() const
 
 bool MediaQueryList::evaluate()
 {
+    if (!m_document)
+        return false;
+
     bool now_matches = false;
     for (auto& media : m_media) {
-        now_matches = now_matches || media.evaluate(m_document.window());
+        now_matches = now_matches || media.evaluate(m_document->window());
     }
 
     return now_matches;

Userland/Libraries/LibWeb/CSS/MediaQueryList.h

@@ -54,7 +54,7 @@ public:
 private:
     MediaQueryList(DOM::Document&, NonnullRefPtrVector<MediaQuery>&&);
 
-    DOM::Document& m_document;
+    WeakPtr<DOM::Document> m_document;
     NonnullRefPtrVector<MediaQuery> m_media;
 };
 

Userland/Services/AudioServer/main.cpp

@@ -23,8 +23,7 @@ ErrorOr<int> serenity_main(Main::Arguments)
     Core::EventLoop event_loop;
     auto mixer = TRY(AudioServer::Mixer::try_create(config));
     auto server = TRY(Core::LocalServer::try_create());
-    bool ok = server->take_over_from_system_server();
-    VERIFY(ok);
+    TRY(server->take_over_from_system_server());
 
     server->on_accept = [&](NonnullRefPtr<Core::LocalSocket> client_socket) {
         static int s_next_client_id = 0;

Userland/Services/Clipboard/main.cpp

@@ -19,8 +19,7 @@ ErrorOr<int> serenity_main(Main::Arguments)
     TRY(Core::System::unveil(nullptr, nullptr));
 
     auto server = TRY(Core::LocalServer::try_create());
-    bool ok = server->take_over_from_system_server();
-    VERIFY(ok);
+    TRY(server->take_over_from_system_server());
 
     server->on_accept = [&](auto client_socket) {
         static int s_next_client_id = 0;

Userland/Services/ConfigServer/main.cpp

@@ -17,10 +17,9 @@ ErrorOr<int> serenity_main(Main::Arguments)
     TRY(Core::System::unveil(nullptr, nullptr));
 
     Core::EventLoop event_loop;
-    auto server = TRY(Core::LocalServer::try_create());
 
-    bool ok = server->take_over_from_system_server();
-    VERIFY(ok);
+    auto server = TRY(Core::LocalServer::try_create());
+    TRY(server->take_over_from_system_server());
     server->on_accept = [&](auto client_socket) {
         static int s_next_client_id = 0;
         int client_id = ++s_next_client_id;

Userland/Services/InspectorServer/main.cpp

@@ -19,8 +19,7 @@ ErrorOr<int> serenity_main(Main::Arguments)
 
     TRY(Core::System::pledge("stdio unix accept"));
 
-    bool ok = server->take_over_from_system_server("/tmp/portal/inspector");
-    VERIFY(ok);
+    TRY(server->take_over_from_system_server("/tmp/portal/inspector"));
     server->on_accept = [&](auto client_socket) {
         static int s_next_client_id = 0;
         int client_id = ++s_next_client_id;
@@ -28,8 +27,7 @@ ErrorOr<int> serenity_main(Main::Arguments)
     };
 
     auto inspectables_server = TRY(Core::LocalServer::try_create());
-    if (!inspectables_server->take_over_from_system_server("/tmp/portal/inspectables"))
-        VERIFY_NOT_REACHED();
+    TRY(inspectables_server->take_over_from_system_server("/tmp/portal/inspectables"));
 
     inspectables_server->on_accept = [&](auto client_socket) {
         auto pid = client_socket->peer_pid();

Userland/Services/LaunchServer/main.cpp

@@ -23,8 +23,7 @@ ErrorOr<int> serenity_main(Main::Arguments)
 
     TRY(Core::System::pledge("stdio accept rpath proc exec"));
 
-    bool ok = server->take_over_from_system_server();
-    VERIFY(ok);
+    TRY(server->take_over_from_system_server());
     server->on_accept = [&](auto client_socket) {
         static int s_next_client_id = 0;
         int client_id = ++s_next_client_id;

Userland/Services/LookupServer/LookupServer.cpp

@@ -78,8 +78,7 @@ LookupServer::LookupServer()
         int client_id = ++s_next_client_id;
         (void)IPC::new_client_connection<ClientConnection>(move(client_socket), client_id);
     };
-    bool ok = m_local_server->take_over_from_system_server();
-    VERIFY(ok);
+    MUST(m_local_server->take_over_from_system_server());
 }
 
 void LookupServer::load_etc_hosts()

Userland/Services/NotificationServer/main.cpp

@@ -18,8 +18,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     auto app = TRY(GUI::Application::try_create(arguments));
     auto server = TRY(Core::LocalServer::try_create());
 
-    bool ok = server->take_over_from_system_server();
-    VERIFY(ok);
+    TRY(server->take_over_from_system_server());
     server->on_accept = [&](auto client_socket) {
         static int s_next_client_id = 0;
         int client_id = ++s_next_client_id;

Userland/Services/SQLServer/main.cpp

@@ -25,10 +25,9 @@ ErrorOr<int> serenity_main(Main::Arguments)
     TRY(Core::System::unveil(nullptr, nullptr));
 
     Core::EventLoop event_loop;
-    auto server = TRY(Core::LocalServer::try_create());
-    bool ok = server->take_over_from_system_server();
-    VERIFY(ok);
 
+    auto server = TRY(Core::LocalServer::try_create());
+    TRY(server->take_over_from_system_server());
     server->on_accept = [&](auto client_socket) {
         static int s_next_client_id = 0;
         int client_id = ++s_next_client_id;

Userland/Services/WindowServer/EventLoop.cpp

@@ -25,10 +25,8 @@ EventLoop::EventLoop()
     m_keyboard_fd = open("/dev/keyboard0", O_RDONLY | O_NONBLOCK | O_CLOEXEC);
     m_mouse_fd = open("/dev/mouse0", O_RDONLY | O_NONBLOCK | O_CLOEXEC);
 
-    bool ok = m_window_server->take_over_from_system_server("/tmp/portal/window");
-    VERIFY(ok);
-    ok = m_wm_server->take_over_from_system_server("/tmp/portal/wm");
-    VERIFY(ok);
+    MUST(m_window_server->take_over_from_system_server("/tmp/portal/window"));
+    MUST(m_wm_server->take_over_from_system_server("/tmp/portal/wm"));
 
     m_window_server->on_accept = [&](auto client_socket) {
         static int s_next_client_id = 0;