LibWeb+WebContent: Spawn Worker processes from the chrome

Instead of spawning these processes from the WebContent process, we now
create them in the Browser chrome.

Part 1/N of "all processes are owned by the chrome".

Userland/Libraries/LibWeb/Forward.h

@@ -457,6 +457,7 @@ class Window;
 class WindowEnvironmentSettingsObject;
 class WindowProxy;
 class Worker;
+class WorkerAgent;
 class WorkerDebugConsoleClient;
 class WorkerEnvironmentSettingsObject;
 class WorkerGlobalScope;

Userland/Libraries/LibWeb/HTML/WorkerAgent.cpp

@@ -4,93 +4,11 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <AK/LexicalPath.h>
-#include <LibCore/Socket.h>
-#include <LibCore/System.h>
+#include <LibWeb/Bindings/HostDefined.h>
 #include <LibWeb/HTML/WorkerAgent.h>
+#include <LibWeb/Page/Page.h>
 #include <LibWeb/Worker/WebWorkerClient.h>
 
-// FIXME: Deduplicate this code with ladybird!!
-
-#ifndef AK_OS_SERENITY
-namespace {
-
-ErrorOr<String> application_directory()
-{
-    auto current_executable_path = TRY(Core::System::current_executable_path());
-    auto dirname = LexicalPath::dirname(current_executable_path);
-    return String::from_byte_string(dirname);
-}
-
-ErrorOr<Vector<String>> get_paths_for_helper_process(StringView process_name)
-{
-    auto application_path = TRY(application_directory());
-    Vector<String> paths;
-
-    TRY(paths.try_append(TRY(String::formatted("{}/{}", application_path, process_name))));
-    TRY(paths.try_append(TRY(String::formatted("./{}", process_name))));
-    // NOTE: Add platform-specific paths here
-    return paths;
-}
-
-ErrorOr<NonnullRefPtr<Web::HTML::WebWorkerClient>> launch_web_worker_process(ReadonlySpan<String> candidate_web_content_paths)
-{
-    int socket_fds[2] {};
-    TRY(Core::System::socketpair(AF_LOCAL, SOCK_STREAM, 0, socket_fds));
-
-    int ui_fd = socket_fds[0];
-    int wc_fd = socket_fds[1];
-
-    int fd_passing_socket_fds[2] {};
-    TRY(Core::System::socketpair(AF_LOCAL, SOCK_STREAM, 0, fd_passing_socket_fds));
-
-    int ui_fd_passing_fd = fd_passing_socket_fds[0];
-    int wc_fd_passing_fd = fd_passing_socket_fds[1];
-
-    if (auto child_pid = TRY(Core::System::fork()); child_pid == 0) {
-        TRY(Core::System::close(ui_fd_passing_fd));
-        TRY(Core::System::close(ui_fd));
-
-        auto takeover_string = TRY(String::formatted("WebWorker:{}", wc_fd));
-        TRY(Core::System::setenv("SOCKET_TAKEOVER"sv, takeover_string, true));
-
-        auto webcontent_fd_passing_socket_string = TRY(String::number(wc_fd_passing_fd));
-
-        ErrorOr<void> result;
-        for (auto const& path : candidate_web_content_paths) {
-            if (Core::System::access(path, X_OK).is_error())
-                continue;
-
-            auto arguments = Vector {
-                path.bytes_as_string_view(),
-                "--fd-passing-socket"sv,
-                webcontent_fd_passing_socket_string
-            };
-
-            result = Core::System::exec(arguments[0], arguments.span(), Core::System::SearchInPath::Yes);
-            if (!result.is_error())
-                break;
-        }
-
-        if (result.is_error())
-            warnln("Could not launch any of {}: {}", candidate_web_content_paths, result.error());
-        VERIFY_NOT_REACHED();
-    }
-
-    TRY(Core::System::close(wc_fd_passing_fd));
-    TRY(Core::System::close(wc_fd));
-
-    auto socket = TRY(Core::LocalSocket::adopt_fd(ui_fd));
-    TRY(socket->set_blocking(true));
-
-    auto new_client = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) Web::HTML::WebWorkerClient(move(socket))));
-    new_client->set_fd_passing_socket(TRY(Core::LocalSocket::adopt_fd(ui_fd_passing_fd)));
-
-    return new_client;
-}
-}
-#endif
-
 namespace Web::HTML {
 
 JS_DEFINE_ALLOCATOR(WorkerAgent);
@@ -109,16 +27,20 @@ void WorkerAgent::initialize(JS::Realm& realm)
     m_message_port = MessagePort::create(realm);
     m_message_port->entangle_with(*m_outside_port);
 
-#ifndef AK_OS_SERENITY
-    auto paths = MUST(get_paths_for_helper_process("WebWorker"sv));
-    m_worker_ipc = MUST(launch_web_worker_process(paths));
-#else
-    m_worker_ipc = MUST(Web::HTML::WebWorkerClient::try_create());
-#endif
-
     TransferDataHolder data_holder;
     MUST(m_message_port->transfer_steps(data_holder));
 
+    // NOTE: This blocking IPC call may launch another process.
+    //    If spinning the event loop for this can cause other javascript to execute, we're in trouble.
+    auto worker_ipc_sockets = Bindings::host_defined_page(realm).client().request_worker_agent();
+    auto worker_socket = MUST(Core::LocalSocket::adopt_fd(worker_ipc_sockets.socket.take_fd()));
+    MUST(worker_socket->set_blocking(true));
+
+    auto fd_passing_socket = MUST(Core::LocalSocket::adopt_fd(worker_ipc_sockets.fd_passing_socket.take_fd()));
+
+    m_worker_ipc = make_ref_counted<WebWorkerClient>(move(worker_socket));
+    m_worker_ipc->set_fd_passing_socket(move(fd_passing_socket));
+
     m_worker_ipc->async_start_dedicated_worker(m_url, m_worker_options.type, m_worker_options.credentials, m_worker_options.name, move(data_holder));
 }
 

Userland/Libraries/LibWeb/HTML/WorkerAgent.h

@@ -6,12 +6,8 @@
 
 #pragma once
 
-#include <LibCore/Socket.h>
 #include <LibWeb/Forward.h>
-#include <LibWeb/HTML/MessageEvent.h>
 #include <LibWeb/HTML/MessagePort.h>
-#include <LibWeb/HTML/Scripting/WorkerEnvironmentSettingsObject.h>
-#include <LibWeb/HTML/Window.h>
 #include <LibWeb/Worker/WebWorkerClient.h>
 
 namespace Web::HTML {
@@ -22,14 +18,12 @@ struct WorkerOptions {
     String name { String {} };
 };
 
-struct WorkerAgent : JS::Cell {
+class WorkerAgent : public JS::Cell {
     JS_CELL(Agent, JS::Cell);
     JS_DECLARE_ALLOCATOR(WorkerAgent);
 
     WorkerAgent(AK::URL url, WorkerOptions const& options, JS::GCPtr<MessagePort> outside_port);
 
-    RefPtr<Web::HTML::WebWorkerClient> m_worker_ipc;
-
 private:
     virtual void initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
@@ -39,6 +33,8 @@ private:
 
     JS::GCPtr<MessagePort> m_message_port;
     JS::GCPtr<MessagePort> m_outside_port;
+
+    RefPtr<Web::HTML::WebWorkerClient> m_worker_ipc;
 };
 
 }

Userland/Libraries/LibWeb/Page/Page.h

@@ -34,6 +34,7 @@
 #include <LibWeb/HTML/SelectItem.h>
 #include <LibWeb/Loader/FileRequest.h>
 #include <LibWeb/PixelUnits.h>
+#include <LibWebView/SocketPair.h>
 
 namespace Web {
 
@@ -284,6 +285,8 @@ public:
 
     virtual void page_did_insert_clipboard_entry([[maybe_unused]] String data, [[maybe_unused]] String presentation_style, [[maybe_unused]] String mime_type) { }
 
+    virtual WebView::SocketPair request_worker_agent() { return { -1, -1 }; }
+
     virtual void inspector_did_load() { }
     virtual void inspector_did_select_dom_node([[maybe_unused]] i32 node_id, [[maybe_unused]] Optional<CSS::Selector::PseudoElement::Type> const& pseudo_element) { }
     virtual void inspector_did_set_dom_node_text([[maybe_unused]] i32 node_id, [[maybe_unused]] String const& text) { }

Userland/Libraries/LibWeb/Worker/WebWorkerClient.cpp

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <LibCore/System.h>
 #include <LibWeb/Worker/WebWorkerClient.h>
 
 namespace Web::HTML {
@@ -18,4 +19,12 @@ WebWorkerClient::WebWorkerClient(NonnullOwnPtr<Core::LocalSocket> socket)
 {
 }
 
+WebView::SocketPair WebWorkerClient::dup_sockets()
+{
+    WebView::SocketPair pair;
+    pair.socket = MUST(Core::System::dup(socket().fd().value()));
+    pair.fd_passing_socket = MUST(Core::System::dup(fd_passing_socket().fd().value()));
+    return pair;
+}
+
 }

Userland/Libraries/LibWeb/Worker/WebWorkerClient.h

@@ -10,6 +10,7 @@
 #include <LibIPC/ConnectionToServer.h>
 #include <LibWeb/Worker/WebWorkerClientEndpoint.h>
 #include <LibWeb/Worker/WebWorkerServerEndpoint.h>
+#include <LibWebView/SocketPair.h>
 
 namespace Web::HTML {
 
@@ -21,6 +22,8 @@ class WebWorkerClient final
 public:
     explicit WebWorkerClient(NonnullOwnPtr<Core::LocalSocket>);
 
+    WebView::SocketPair dup_sockets();
+
 private:
     virtual void die() override;
 };

Userland/Libraries/LibWebView/CMakeLists.txt

@@ -8,6 +8,7 @@ set(SOURCES
     InspectorClient.cpp
     RequestServerAdapter.cpp
     SearchEngine.cpp
+    SocketPair.cpp
     SourceHighlighter.cpp
     URL.cpp
     UserAgent.cpp

Userland/Libraries/LibWebView/Forward.h

@@ -21,6 +21,7 @@ class WebContentClient;
 struct Attribute;
 struct CookieStorageKey;
 struct SearchEngine;
+struct SocketPair;
 
 }
 

Userland/Libraries/LibWebView/OutOfProcessWebView.cpp

@@ -17,6 +17,7 @@
 #include <LibGfx/Palette.h>
 #include <LibGfx/SystemTheme.h>
 #include <LibWeb/Crypto/Crypto.h>
+#include <LibWeb/Worker/WebWorkerClient.h>
 
 REGISTER_WIDGET(WebView, OutOfProcessWebView)
 
@@ -71,6 +72,11 @@ OutOfProcessWebView::OutOfProcessWebView()
     on_finish_handling_input_event = [this](auto event_was_accepted) {
         did_finish_handling_input_event(event_was_accepted);
     };
+
+    on_request_worker_agent = []() {
+        auto worker_client = MUST(Web::HTML::WebWorkerClient::try_create());
+        return worker_client->dup_sockets();
+    };
 }
 
 OutOfProcessWebView::~OutOfProcessWebView() = default;

Userland/Libraries/LibWebView/SocketPair.cpp

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2024, Andrew Kaster <akaster@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibIPC/Decoder.h>
+#include <LibIPC/Encoder.h>
+#include <LibWebView/SocketPair.h>
+
+template<>
+ErrorOr<void> IPC::encode(Encoder& encoder, WebView::SocketPair const& pair)
+{
+    TRY(encoder.encode(pair.socket));
+    TRY(encoder.encode(pair.fd_passing_socket));
+    return {};
+}
+
+template<>
+ErrorOr<WebView::SocketPair> IPC::decode(Decoder& decoder)
+{
+    auto socket = TRY(decoder.decode<IPC::File>());
+    auto fd_passing_socket = TRY(decoder.decode<IPC::File>());
+
+    return WebView::SocketPair { move(socket), move(fd_passing_socket) };
+}

Userland/Libraries/LibWebView/SocketPair.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2024, Andrew Kaster <akaster@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibIPC/File.h>
+
+namespace WebView {
+
+struct SocketPair {
+    IPC::File socket;
+    IPC::File fd_passing_socket;
+};
+
+}
+
+namespace IPC {
+
+template<>
+ErrorOr<void> encode(Encoder&, WebView::SocketPair const&);
+
+template<>
+ErrorOr<WebView::SocketPair> decode(Decoder&);
+
+}

Userland/Libraries/LibWebView/ViewImplementation.h

@@ -177,6 +177,7 @@ public:
     Function<void(i32, String const&, Vector<Attribute> const&)> on_inspector_replaced_dom_node_attribute;
     Function<void(i32, Gfx::IntPoint, String const&, Optional<String> const&, Optional<Attribute> const&)> on_inspector_requested_dom_tree_context_menu;
     Function<void(String const&)> on_inspector_executed_console_script;
+    Function<SocketPair()> on_request_worker_agent;
 
     virtual Web::DevicePixelRect viewport_rect() const = 0;
     virtual Gfx::IntPoint to_content_position(Gfx::IntPoint widget_position) const = 0;

Userland/Libraries/LibWebView/WebContentClient.cpp

@@ -478,4 +478,12 @@ void WebContentClient::inspector_did_execute_console_script(String const& script
         m_view.on_inspector_executed_console_script(script);
 }
 
+Messages::WebContentClient::RequestWorkerAgentResponse WebContentClient::request_worker_agent()
+{
+    if (m_view.on_request_worker_agent)
+        return m_view.on_request_worker_agent();
+
+    return Messages::WebContentClient::RequestWorkerAgentResponse { WebView::SocketPair { -1, -1 } };
+}
+
 }

Userland/Libraries/LibWebView/WebContentClient.h

@@ -98,6 +98,7 @@ private:
     virtual void inspector_did_replace_dom_node_attribute(i32 node_id, String const& name, Vector<Attribute> const& replacement_attributes) override;
     virtual void inspector_did_request_dom_tree_context_menu(i32 node_id, Gfx::IntPoint position, String const& type, Optional<String> const& tag, Optional<Attribute> const& attribute) override;
     virtual void inspector_did_execute_console_script(String const& script) override;
+    virtual Messages::WebContentClient::RequestWorkerAgentResponse request_worker_agent() override;
 
     ViewImplementation& m_view;
 };