chrome/browser/chrome_browser_main_extra_parts_linux.cc

   1 // Copyright 2021 The Chromium Authors
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/chrome_browser_main_extra_parts_linux.h"
   6
   7 #include "base/command_line.h"
   8 #include "base/environment.h"
   9 #include "base/logging.h"
  10 #include "build/build_config.h"
  11 #include "ui/ozone/buildflags.h"
  12 #include "ui/ozone/public/ozone_switches.h"
  13
  14 #if BUILDFLAG(OZONE_PLATFORM_WAYLAND)
  15 #include "base/files/file_path.h"
  16 #include "base/files/file_util.h"
  17 #include "base/nix/xdg_util.h"
  18 #include "base/threading/thread_restrictions.h"
  19 #endif  // BUILDFLAG(OZONE_PLATFORM_WAYLAND)
  20
  21 #if BUILDFLAG(OZONE_PLATFORM_WAYLAND)
  22
  23 constexpr char kPlatformWayland[] = "wayland";
  24
  25 bool HasWaylandDisplay(base::Environment* env) {
  26   std::string wayland_display;
  27   const bool has_wayland_display =
  28       env->GetVar("WAYLAND_DISPLAY", &wayland_display) &&
  29       !wayland_display.empty();
  30   if (has_wayland_display)
  31     return true;
  32
  33   std::string xdg_runtime_dir;
  34   const bool has_xdg_runtime_dir =
  35       env->GetVar("XDG_RUNTIME_DIR", &xdg_runtime_dir) &&
  36       !xdg_runtime_dir.empty();
  37   if (has_xdg_runtime_dir) {
  38     auto wayland_server_pipe =
  39         base::FilePath(xdg_runtime_dir).Append("wayland-0");
  40     // Normally, this should happen exactly once, at the startup of the main
  41     // process.
  42     base::ScopedAllowBlocking allow_blocking;
  43     return base::PathExists(wayland_server_pipe);
  44   }
  45
  46   return false;
  47 }
  48
  49 #endif  // BUILDFLAG(OZONE_PLATFORM_WAYLAND)
  50
  51 #if BUILDFLAG(OZONE_PLATFORM_X11)
  52 constexpr char kPlatformX11[] = "x11";
  53 #endif
  54
  55 namespace {
  56
  57 // Evaluates the environment and returns the effective platform name for the
  58 // given |ozone_platform_hint|.
  59 // For the "auto" value, returns "wayland" if the XDG session type is "wayland",
  60 // "x11" otherwise.
  61 // For the "wayland" value, checks if the Wayland server is available, and
  62 // returns "x11" if it is not.
  63 // See https://crbug.com/1246928.
  64 std::string MaybeFixPlatformName(const std::string& ozone_platform_hint) {
  65 #if BUILDFLAG(OZONE_PLATFORM_WAYLAND)
  66   // Wayland is selected if both conditions below are true:
  67   // 1. The user selected either 'wayland' or 'auto'.
  68   // 2. The XDG session type is 'wayland', OR the user has selected 'wayland'
  69   //    explicitly and a Wayland server is running.
  70   // Otherwise, fall back to X11.
  71   if (ozone_platform_hint == kPlatformWayland ||
  72       ozone_platform_hint == "auto") {
  73     auto env(base::Environment::Create());
  74
  75     std::string xdg_session_type;
  76     const bool has_xdg_session_type =
  77         env->GetVar(base::nix::kXdgSessionTypeEnvVar, &xdg_session_type) &&
  78         !xdg_session_type.empty();
  79
  80     if ((has_xdg_session_type && xdg_session_type == "wayland") ||
  81         (ozone_platform_hint == kPlatformWayland &&
  82          HasWaylandDisplay(env.get()))) {
  83       return kPlatformWayland;
  84     }
  85   }
  86 #endif  // BUILDFLAG(OZONE_PLATFORM_WAYLAND)
  87
  88 #if BUILDFLAG(OZONE_PLATFORM_X11)
  89   if (ozone_platform_hint == kPlatformX11) {
  90     return kPlatformX11;
  91   }
  92 #if BUILDFLAG(OZONE_PLATFORM_WAYLAND)
  93   if (ozone_platform_hint == kPlatformWayland ||
  94       ozone_platform_hint == "auto") {
  95     // We are here if:
  96     // - The binary has both X11 and Wayland backends.
  97     // - The user wanted Wayland but that did not work, otherwise it would have
  98     //   been returned above.
  99     if (ozone_platform_hint == kPlatformWayland) {
 100       LOG(WARNING) << "No Wayland server is available. Falling back to X11.";
 101     } else {
 102       LOG(WARNING) << "This is not a Wayland session.  Falling back to X11. "
 103                       "If you need to run Chrome on Wayland using some "
 104                       "embedded compositor, e. g., Weston, please specify "
 105                       "Wayland as your preferred Ozone platform, or use "
 106                       "--ozone-platform=wayland.";
 107     }
 108     return kPlatformX11;
 109   }
 110 #endif  // BUILDFLAG(OZONE_PLATFORM_WAYLAND)
 111 #endif  // BUILDFLAG(OZONE_PLATFORM_X11)
 112
 113   return ozone_platform_hint;
 114 }
 115
 116 }  // namespace
 117
 118 ChromeBrowserMainExtraPartsLinux::ChromeBrowserMainExtraPartsLinux() = default;
 119
 120 ChromeBrowserMainExtraPartsLinux::~ChromeBrowserMainExtraPartsLinux() = default;
 121
 122 void ChromeBrowserMainExtraPartsLinux::PreEarlyInitialization() {
 123 #if BUILDFLAG(IS_LINUX)
 124   // On the desktop, we fix the platform name if necessary.
 125   // See https://crbug.com/1246928.
 126   auto* const command_line = base::CommandLine::ForCurrentProcess();
 127   if (!command_line->HasSwitch(switches::kOzonePlatform)) {
 128     const auto ozone_platform_hint =
 129         command_line->GetSwitchValueASCII(switches::kOzonePlatformHint);
 130     if (!ozone_platform_hint.empty()) {
 131       command_line->AppendSwitchASCII(
 132           switches::kOzonePlatform, MaybeFixPlatformName(ozone_platform_hint));
 133     }
 134   }
 135
 136   auto env = base::Environment::Create();
 137   std::string desktop_startup_id;
 138   if (env->GetVar("DESKTOP_STARTUP_ID", &desktop_startup_id))
 139     command_line->AppendSwitchASCII("desktop-startup-id", desktop_startup_id);
 140 #endif  // BUILDFLAG(IS_LINUX)
 141
 142   ChromeBrowserMainExtraPartsOzone::PreEarlyInitialization();
 143 }