LibCore: Return ErrorOr<pid_t> and support arguments in Process::spawn

This makes the wrapper more like the rest in LibCore, and also
removes the annoying limitation of not supporting arguments.

There are three overloads one for String, char const *, and StringView
argument lists. As long as there are <= 10 arguments the argv list
will be allocated inline, otherwise on the heap.

Userland/Applets/Keymap/KeymapStatusWindow.cpp

@@ -16,7 +16,7 @@ void KeymapStatusWidget::mousedown_event(GUI::MouseEvent& event)
     if (event.button() != GUI::MouseButton::Primary)
         return;
 
-    Core::Process::spawn("/bin/KeyboardSettings");
+    MUST(Core::Process::spawn("/bin/KeyboardSettings"));
 }
 
 KeymapStatusWindow::KeymapStatusWindow()

Userland/Applications/Browser/BrowserWindow.cpp

@@ -302,7 +302,7 @@ void BrowserWindow::build_menus()
     settings_menu.add_separator();
     auto open_settings_action = GUI::Action::create("&Settings", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/settings.png").release_value_but_fixme_should_propagate_errors(),
         [](auto&) {
-            Core::Process::spawn("/bin/BrowserSettings");
+            MUST(Core::Process::spawn("/bin/BrowserSettings"));
         });
     settings_menu.add_action(move(open_settings_action));
 

Userland/Applications/Settings/main.cpp

@@ -104,7 +104,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
         auto launch_origin_rect = icon_view->to_widget_rect(icon_view->content_rect(index)).translated(icon_view->screen_relative_rect().location());
         setenv("__libgui_launch_origin_rect", String::formatted("{},{},{},{}", launch_origin_rect.x(), launch_origin_rect.y(), launch_origin_rect.width(), launch_origin_rect.height()).characters(), 1);
-        Core::Process::spawn(executable);
+        MUST(Core::Process::spawn(executable));
     };
 
     auto statusbar = TRY(main_widget->try_add<GUI::Statusbar>());

Userland/Applications/Terminal/main.cpp

@@ -328,7 +328,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
     auto open_settings_action = GUI::Action::create("&Settings", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/settings.png").release_value_but_fixme_should_propagate_errors(),
         [&](auto&) {
-            Core::Process::spawn("/bin/TerminalSettings");
+            MUST(Core::Process::spawn("/bin/TerminalSettings"));
         });
 
     TRY(terminal->context_menu().try_add_separator());
@@ -336,7 +336,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
     auto file_menu = TRY(window->try_add_menu("&File"));
     TRY(file_menu->try_add_action(GUI::Action::create("Open New &Terminal", { Mod_Ctrl | Mod_Shift, Key_N }, Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-terminal.png").release_value_but_fixme_should_propagate_errors(), [&](auto&) {
-        Core::Process::spawn("/bin/Terminal");
+        MUST(Core::Process::spawn("/bin/Terminal"));
     })));
 
     TRY(file_menu->try_add_action(open_settings_action));

Userland/Applications/Welcome/WelcomeWidget.cpp

@@ -54,7 +54,7 @@ WelcomeWidget::WelcomeWidget()
     m_help_button = *find_descendant_of_type_named<GUI::Button>("help_button");
     m_help_button->set_icon(Gfx::Bitmap::try_load_from_file("/res/icons/16x16/book-open.png").release_value_but_fixme_should_propagate_errors());
     m_help_button->on_click = [](auto) {
-        Core::Process::spawn("/bin/Help"sv);
+        MUST(Core::Process::spawn("/bin/Help"sv));
     };
 
     m_new_button = *find_descendant_of_type_named<GUI::Button>("new_button");

Userland/Libraries/LibCore/Process.cpp

@@ -1,11 +1,14 @@
 /*
  * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2022, MacDue <macdue@dueutil.tech>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include <AK/String.h>
+#include <AK/Vector.h>
 #include <LibCore/Process.h>
+#include <LibCore/System.h>
 #include <errno.h>
 #include <spawn.h>
 
@@ -17,21 +20,65 @@ extern char** environ;
 
 namespace Core {
 
-pid_t Process::spawn(StringView path)
+struct ArgvList {
-{
+    String m_path;
-    String path_string = path;
+    Vector<char const*, 10> m_argv;
 
-    pid_t pid;
+    ArgvList(String path, size_t size)
-    char const* argv[] = { path_string.characters(), nullptr };
+        : m_path { path }
-    if ((errno = posix_spawn(&pid, path_string.characters(), nullptr, nullptr, const_cast<char**>(argv), environ))) {
+    {
-        perror("Process::spawn posix_spawn");
+        m_argv.ensure_capacity(size + 2);
-    } else {
+        m_argv.append(m_path.characters());
-#ifdef __serenity__
-        if (disown(pid) < 0)
-            perror("Process::spawn disown");
-#endif
     }
-    return pid;
+
+    void append(char const* arg)
+    {
+        m_argv.append(arg);
+    }
+
+    Span<char const*> get()
+    {
+        if (m_argv.is_empty() || m_argv.last() != nullptr)
+            m_argv.append(nullptr);
+        return m_argv;
+    }
+
+    ErrorOr<pid_t> spawn()
+    {
+        auto pid = TRY(System::posix_spawn(m_path.characters(), nullptr, nullptr, const_cast<char**>(get().data()), environ));
+#ifdef __serenity__
+        TRY(System::disown(pid));
+#endif
+        return pid;
+    }
+};
+
+ErrorOr<pid_t> Process::spawn(StringView path, Span<String const> arguments)
+{
+    ArgvList argv { path, arguments.size() };
+    for (auto const& arg : arguments)
+        argv.append(arg.characters());
+    return argv.spawn();
+}
+
+ErrorOr<pid_t> Process::spawn(StringView path, Span<StringView const> arguments)
+{
+    Vector<String> backing_strings;
+    backing_strings.ensure_capacity(arguments.size());
+    ArgvList argv { path, arguments.size() };
+    for (auto const& arg : arguments) {
+        backing_strings.append(arg);
+        argv.append(backing_strings.last().characters());
+    }
+    return argv.spawn();
+}
+
+ErrorOr<pid_t> Process::spawn(StringView path, Span<char const* const> arguments)
+{
+    ArgvList argv { path, arguments.size() };
+    for (auto arg : arguments)
+        argv.append(arg);
+    return argv.spawn();
 }
 
 }

Userland/Libraries/LibCore/Process.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2022, MacDue <macdue@dueutil.tech>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -7,12 +8,15 @@
 #pragma once
 
 #include <AK/Forward.h>
+#include <AK/Span.h>
 
 namespace Core {
 
 class Process {
 public:
-    static pid_t spawn(StringView path);
+    static ErrorOr<pid_t> spawn(StringView path, Span<String const> arguments);
+    static ErrorOr<pid_t> spawn(StringView path, Span<StringView const> arguments);
+    static ErrorOr<pid_t> spawn(StringView path, Span<char const* const> arguments = {});
 };
 
 }

Userland/Libraries/LibDesktop/AppFile.cpp

@@ -130,7 +130,7 @@ bool AppFile::spawn() const
         return false;
 
     auto pid = Core::Process::spawn(executable());
-    if (pid < 0)
+    if (pid.is_error())
         return false;
 
     return true;

Userland/Services/Taskbar/ClockWidget.cpp

@@ -154,7 +154,7 @@ ClockWidget::ClockWidget()
     m_calendar_launcher->set_icon(Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-calendar.png").release_value_but_fixme_should_propagate_errors());
     m_calendar_launcher->set_tooltip("Calendar");
     m_calendar_launcher->on_click = [](auto) {
-        Core::Process::spawn("/bin/Calendar"sv);
+        MUST(Core::Process::spawn("/bin/Calendar"));
     };
 }
 

Userland/Services/Taskbar/QuickLaunchWidget.cpp

@@ -48,9 +48,7 @@ ErrorOr<void> QuickLaunchEntryAppFile::launch() const
 
 ErrorOr<void> QuickLaunchEntryExecutable::launch() const
 {
-    auto pid = Core::Process::spawn(m_path);
+    TRY(Core::Process::spawn(m_path));
-    if (pid < 0)
-        return Error::from_syscall("Core::Process::spawn", -errno);
     return {};
 }
 

Userland/Services/Taskbar/main.cpp

@@ -109,7 +109,7 @@ ErrorOr<NonnullRefPtr<GUI::Menu>> build_system_menu()
     auto system_menu = TRY(GUI::Menu::try_create("\xE2\x9A\xA1")); // HIGH VOLTAGE SIGN
 
     system_menu->add_action(GUI::Action::create("&About SerenityOS", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/ladyball.png").release_value_but_fixme_should_propagate_errors(), [](auto&) {
-        Core::Process::spawn("/bin/About"sv);
+        MUST(Core::Process::spawn("/bin/About"sv));
     }));
 
     system_menu->add_separator();
@@ -229,12 +229,12 @@ ErrorOr<NonnullRefPtr<GUI::Menu>> build_system_menu()
     }
 
     system_menu->add_action(GUI::Action::create("&Settings", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-settings.png").release_value_but_fixme_should_propagate_errors(), [](auto&) {
-        Core::Process::spawn("/bin/Settings"sv);
+        MUST(Core::Process::spawn("/bin/Settings"sv));
     }));
 
     system_menu->add_separator();
     system_menu->add_action(GUI::Action::create("&Help", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-help.png").release_value_but_fixme_should_propagate_errors(), [](auto&) {
-        Core::Process::spawn("/bin/Help"sv);
+        MUST(Core::Process::spawn("/bin/Help"sv));
     }));
     system_menu->add_action(GUI::Action::create("&Run...", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-run.png").release_value_but_fixme_should_propagate_errors(), [](auto&) {
         posix_spawn_file_actions_t spawn_actions;