3 files changed, 886 insertions, 0 deletions

diff --git a/third_party/wayland-proxy/moz.build b/third_party/wayland-proxy/moz.build
new file mode 100644
index 0000000000..e95f18f541
--- /dev/null
+++ b/third_party/wayland-proxy/moz.build
@@ -0,0 +1,16 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "Widget: Gtk")
+
+SOURCES += [
+    "wayland-proxy.cpp",
+]
+EXPORTS += [
+    "wayland-proxy.h",
+]
+FINAL_LIBRARY = "xul"
diff --git a/third_party/wayland-proxy/wayland-proxy.cpp b/third_party/wayland-proxy/wayland-proxy.cpp
new file mode 100644
index 0000000000..900c1162d9
--- /dev/null
+++ b/third_party/wayland-proxy/wayland-proxy.cpp
@@ -0,0 +1,799 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This code is based on Rust implementation at
+// https://github.com/the8472/weyland-p5000
+
+// Version 1.1
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <sys/un.h>
+#include <spawn.h>
+#include <poll.h>
+#include <vector>
+#include <cerrno>
+#include <fcntl.h>
+#include <unistd.h>
+#include <memory>
+#include <cassert>
+#include <pthread.h>
+#include <sched.h>
+
+#include "wayland-proxy.h"
+
+// The maximum number of fds libwayland can recvmsg at once
+#define MAX_LIBWAY_FDS 28
+#define MAX_DATA_SIZE 4096
+#define POLL_TIMEOUT 30000
+
+bool sPrintInfo = false;
+
+void Print(const char* aFormat, ...) {
+  if (!sPrintInfo) {
+    return;
+  }
+  va_list args;
+  va_start(args, aFormat);
+  vfprintf(stderr, aFormat, args);
+  va_end(args);
+}
+
+void Warning(const char* aOperation, bool aPrintErrno = true) {
+  fprintf(stderr, "Warning: %s : %s\n",
+          aOperation,
+          aPrintErrno ? strerror(errno) : "");
+}
+
+void Error(const char* aOperation, bool aPrintErrno = true) {
+  fprintf(stderr, "Error: %s : %s\n",
+          aOperation,
+          aPrintErrno ? strerror(errno) : "");
+}
+
+class WaylandMessage {
+ public:
+  bool Write(int aSocket);
+
+  bool Loaded() const { return mLoaded && (mFds.size() || mData.size()); }
+  bool Failed() const { return mFailed; }
+
+  explicit WaylandMessage(int aSocket) { Read(aSocket); }
+  ~WaylandMessage();
+
+ private:
+  bool Read(int aSocket);
+
+ private:
+  bool mLoaded = false;
+  bool mFailed = false;
+
+  std::vector<int> mFds;
+  std::vector<unsigned char> mData;
+};
+
+class ProxiedConnection {
+ public:
+  bool Init(int aChildSocket, char* aWaylandDisplay);
+  bool IsConnected() { return mCompositorConnected; }
+
+  struct pollfd* AddToPollFd(struct pollfd* aPfds);
+  struct pollfd* LoadPollFd(struct pollfd* aPfds);
+
+  // Process this connection (send/receive data).
+  // Returns false if connection is broken and should be removed.
+  bool Process();
+
+  ~ProxiedConnection();
+
+ private:
+  // Try to connect to compositor. Returns false in case of fatal error.
+  bool ConnectToCompositor();
+
+  bool TransferOrQueue(
+      int aSourceSocket, int aSourcePollFlags, int aDestSocket,
+      std::vector<std::unique_ptr<WaylandMessage>>* aMessageQueue);
+  bool FlushQueue(int aDestSocket, int aDestPollFlags,
+                  std::vector<std::unique_ptr<WaylandMessage>>& aMessageQueue);
+
+  // Where we should connect.
+  // Weak pointer to parent WaylandProxy class.
+  char* mWaylandDisplay = nullptr;
+
+  // We don't have connected compositor yet. Try to connect
+  bool mCompositorConnected = false;
+
+  // We're disconnected from app or compositor. We will close this connection.
+  bool mFailed = false;
+
+  int mCompositorSocket = -1;
+  int mCompositorFlags = 0;
+
+  int mApplicationSocket = -1;
+  int mApplicationFlags = 0;
+
+  // Stored proxied data
+  std::vector<std::unique_ptr<WaylandMessage>> mToCompositorQueue;
+  std::vector<std::unique_ptr<WaylandMessage>> mToApplicationQueue;
+};
+
+WaylandMessage::~WaylandMessage() {
+  for (auto const fd : mFds) {
+    close(fd);
+  }
+}
+
+bool WaylandMessage::Read(int aSocket) {
+  // We don't expect WaylandMessage re-read
+  assert(!mLoaded && !mFailed);
+
+  mData.resize(MAX_DATA_SIZE);
+
+  struct msghdr msg = {0};
+  struct iovec iov = {mData.data(), mData.size()};
+  msg.msg_iov = &iov;
+  msg.msg_iovlen = 1;
+
+  char cmsgdata[(CMSG_LEN(MAX_LIBWAY_FDS * sizeof(int32_t)))] = {0};
+  msg.msg_control = &cmsgdata;
+  msg.msg_controllen = sizeof(cmsgdata);
+
+  ssize_t ret = recvmsg(aSocket, &msg, MSG_CMSG_CLOEXEC | MSG_DONTWAIT);
+  if (msg.msg_flags & (MSG_CTRUNC | MSG_TRUNC)) {
+    Error("WaylandMessage::Read() data truncated, small buffer?");
+    mFailed = true;
+    return false;
+  }
+
+  if (ret < 1) {
+    switch (errno) {
+      case EAGAIN:
+      case EINTR:
+        // Neither loaded nor failed, we'll try again later
+        Print("WaylandMessage::Write() failed %s\n", strerror(errno));
+        return false;
+      default:
+        Error("WaylandMessage::Write() failed");
+        mFailed = true;
+        return false;
+    }
+  }
+
+  // Set correct data size
+  mData.resize(ret);
+
+  // Read cmsg
+  struct cmsghdr* header = CMSG_FIRSTHDR(&msg);
+  while (header) {
+    struct cmsghdr* next = CMSG_NXTHDR(&msg, header);
+    if (header->cmsg_level != SOL_SOCKET || header->cmsg_type != SCM_RIGHTS) {
+      header = next;
+      continue;
+    }
+
+    int* data = (int*)CMSG_DATA(header);
+    int filenum = (int)((header->cmsg_len - CMSG_LEN(0)) / sizeof(int));
+    for (int i = 0; i < filenum; i++) {
+#ifdef DEBUG
+      int flags = fcntl(data[i], F_GETFL, 0);
+      if (flags == -1 && errno == EBADF) {
+        Error("WaylandMessage::Read() invalid fd");
+      }
+#endif
+      mFds.push_back(data[i]);
+    }
+    header = next;
+  }
+
+  mLoaded = true;
+  return true;
+}
+
+bool WaylandMessage::Write(int aSocket) {
+  if (!mLoaded || mFailed) {
+    return false;
+  }
+
+  struct msghdr msg = {0};
+  struct iovec iov = {mData.data(), mData.size()};
+  msg.msg_iov = &iov;
+  msg.msg_iovlen = 1;
+
+  union {
+    char buf[CMSG_SPACE(sizeof(int) * MAX_LIBWAY_FDS)];
+    struct cmsghdr align;
+  } cmsgu;
+  memset(cmsgu.buf, 0, sizeof(cmsgu.buf));
+
+  int filenum = mFds.size();
+  if (filenum) {
+    if (filenum >= MAX_LIBWAY_FDS) {
+      Error("WaylandMessage::Write() too many files to send\n", false);
+      return false;
+    }
+#ifdef DEBUG
+    for (int i = 0; i < filenum; i++) {
+      int flags = fcntl(mFds[i], F_GETFL, 0);
+      if (flags == -1 && errno == EBADF) {
+        Error("WaylandMessage::Write() invalid fd\n");
+      }
+    }
+#endif
+    msg.msg_control = cmsgu.buf;
+    msg.msg_controllen = CMSG_SPACE(filenum * sizeof(int));
+
+    struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
+    cmsg->cmsg_level = SOL_SOCKET;
+    cmsg->cmsg_type = SCM_RIGHTS;
+    cmsg->cmsg_len = CMSG_LEN(filenum * sizeof(int));
+    memcpy(CMSG_DATA(cmsg), mFds.data(), filenum * sizeof(int));
+  }
+
+  ssize_t ret = sendmsg(aSocket, &msg, MSG_CMSG_CLOEXEC | MSG_DONTWAIT);
+  if (ret < 1) {
+    switch (errno) {
+      case EAGAIN:
+      case EINTR:
+        // Neither loaded nor failed, we'll try again later
+        Print("WaylandMessage::Write() failed %s\n", strerror(errno));
+        return false;
+      default:
+        Warning("WaylandMessage::Write() failed");
+        mFailed = true;
+        return false;
+    }
+  }
+
+  if (ret != (ssize_t)mData.size()) {
+    Print("WaylandMessage::Write() failed to write all data! (%d vs. %d)\n", ret,
+         mData.size());
+  }
+  return true;
+}
+
+ProxiedConnection::~ProxiedConnection() {
+  if (mCompositorSocket != -1) {
+    close(mCompositorSocket);
+  }
+  if (mApplicationSocket != -1) {
+    close(mApplicationSocket);
+  }
+}
+
+bool ProxiedConnection::Init(int aApplicationSocket, char* aWaylandDisplay) {
+  mWaylandDisplay = aWaylandDisplay;
+  mApplicationSocket = aApplicationSocket;
+  mCompositorSocket =
+      socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0);
+  if (mCompositorSocket == -1) {
+    Error("WaylandProxy: ProxiedConnection::Init() socket()");
+  }
+  bool ret = mApplicationSocket >= 0 && mCompositorSocket >= 0;
+  Print("WaylandProxy: ProxiedConnection::Init() %s\n", ret ? "OK" : "FAILED");
+  return ret;
+}
+
+struct pollfd* ProxiedConnection::AddToPollFd(struct pollfd* aPfds) {
+  // Listen application's requests
+  aPfds->fd = mApplicationSocket;
+  aPfds->events = POLLIN;
+
+  // We're connected and we have data for appplication from compositor.
+  // Add POLLOUT to request write to app socket.
+  if (mCompositorConnected && !mToApplicationQueue.empty()) {
+    aPfds->events |= POLLOUT;
+  }
+  aPfds++;
+
+  aPfds->fd = mCompositorSocket;
+  aPfds->events = 0;
+  // We're waiting for connection or we have data for compositor
+  if (!mCompositorConnected || !mToCompositorQueue.empty()) {
+    aPfds->events |= POLLOUT;
+  }
+  if (mCompositorConnected) {
+    aPfds->events |= POLLIN;
+  }
+  aPfds++;
+
+  return aPfds;
+}
+
+struct pollfd* ProxiedConnection::LoadPollFd(struct pollfd* aPfds) {
+  if (aPfds->fd != mApplicationSocket) {
+    return aPfds;
+  }
+  mApplicationFlags = aPfds->revents;
+  aPfds++;
+  mCompositorFlags = aPfds->revents;
+  aPfds++;
+  return aPfds;
+}
+
+bool ProxiedConnection::ConnectToCompositor() {
+  if (!(mCompositorFlags & POLLOUT)) {
+    // Try again later
+    return true;
+  }
+
+  struct sockaddr_un addr = {};
+  addr.sun_family = AF_UNIX;
+  strcpy(addr.sun_path, mWaylandDisplay);
+
+  mCompositorConnected =
+      connect(mCompositorSocket, (const struct sockaddr*)&addr,
+              sizeof(struct sockaddr_un)) != -1;
+  if (!mCompositorConnected) {
+    switch (errno) {
+      case EAGAIN:
+      case EALREADY:
+      case ECONNREFUSED:
+      case EINPROGRESS:
+      case EINTR:
+      case EISCONN:
+      case ETIMEDOUT:
+        // We can recover from these errors and try again
+        Warning("ConnectToCompositor() try again");
+        return true;
+      default:
+        Error("ConnectToCompositor() connect()");
+        return false;
+    }
+  }
+  return true;
+}
+
+// Read data from aSourceSocket and try to twite them to aDestSocket.
+// If data write fails, append them to aMessageQueue.
+// Return
+bool ProxiedConnection::TransferOrQueue(
+    int aSourceSocket, int aSourcePollFlags, int aDestSocket,
+    std::vector<std::unique_ptr<WaylandMessage>>* aMessageQueue) {
+  // Don't read if we don't have any data ready
+  if (!(aSourcePollFlags & POLLIN)) {
+    return true;
+  }
+
+  while (1) {
+    int availableData = 0;
+    if (ioctl(aSourceSocket, FIONREAD, &availableData) < 0) {
+      // Broken connection, we're finished here
+      Warning("ProxiedConnection::TransferOrQueue() broken source socket %s\n");
+      return false;
+    }
+    if (availableData == 0) {
+      return true;
+    }
+
+    auto message = std::make_unique<WaylandMessage>(aSourceSocket);
+    if (message->Failed()) {
+      // Failed to read message due to error
+      return false;
+    }
+    if (!message->Loaded()) {
+      // Let's try again
+      return true;
+    }
+    if (!message->Write(aDestSocket)) {
+      if (message->Failed()) {
+        // Failed to write and we can't recover
+        return false;
+      }
+      aMessageQueue->push_back(std::move(message));
+    }
+  }
+}
+
+// Try to flush all data to aMessageQueue.
+bool ProxiedConnection::FlushQueue(
+    int aDestSocket, int aDestPollFlags,
+    std::vector<std::unique_ptr<WaylandMessage>>& aMessageQueue) {
+  // Can't write to destination yet
+  if (!(aDestPollFlags & POLLOUT) || aMessageQueue.empty()) {
+    return true;
+  }
+
+  std::vector<std::unique_ptr<WaylandMessage>>::iterator message;
+  for (message = aMessageQueue.begin(); message != aMessageQueue.end();) {
+    if (!(*message)->Write(aDestSocket)) {
+      // Failed to write the message, remove whole connection
+      // as it's broken.
+      if ((*message)->Failed()) {
+        return false;
+      }
+      break;
+    }
+    message++;
+  }
+
+  // Remove all written messages at once.
+  if (message != aMessageQueue.begin()) {
+    aMessageQueue.erase(aMessageQueue.begin(), message);
+  }
+
+  return true;
+}
+
+bool ProxiedConnection::Process() {
+  if (mFailed) {
+    return false;
+  }
+
+  // Check if appplication is still listening
+  if (mApplicationFlags & (POLLHUP | POLLERR)) {
+    return false;
+  }
+
+  // Check if compositor is still listening
+  if (mCompositorConnected) {
+    if (mCompositorFlags & (POLLHUP | POLLERR)) {
+      return false;
+    }
+  } else {
+    // Try to reconnect to compositor.
+    if (!ConnectToCompositor()) {
+      Print("Failed to connect to compositor\n");
+      return false;
+    }
+    // We're not connected yet but ConnectToCompositor() didn't return
+    // fatal error. Try again later.
+    if (!mCompositorConnected) {
+      return true;
+    }
+  }
+
+  mFailed =
+      !TransferOrQueue(mCompositorSocket, mCompositorFlags, mApplicationSocket,
+                       &mToApplicationQueue) ||
+      !TransferOrQueue(mApplicationSocket, mApplicationFlags, mCompositorSocket,
+                       &mToCompositorQueue) ||
+      !FlushQueue(mCompositorSocket, mCompositorFlags, mToCompositorQueue) ||
+      !FlushQueue(mApplicationSocket, mApplicationFlags, mToApplicationQueue);
+
+  return !mFailed;
+}
+
+bool WaylandProxy::SetupWaylandDisplays() {
+  char* waylandDisplay = getenv("WAYLAND_DISPLAY_COMPOSITOR");
+  if (!waylandDisplay) {
+    waylandDisplay = getenv("WAYLAND_DISPLAY");
+    if (!waylandDisplay) {
+      Error("Init(), Missing Wayland display, WAYLAND_DISPLAY is empty.",
+            false);
+      return false;
+    }
+  }
+
+  char* XDGRuntimeDir = getenv("XDG_RUNTIME_DIR");
+  if (!XDGRuntimeDir) {
+    Error("Init() Missing XDG_RUNTIME_DIR", false);
+    return false;
+  }
+
+  // WAYLAND_DISPLAY can be absolute path
+  if (waylandDisplay[0] == '/') {
+    if (strlen(mWaylandDisplay) >= sMaxDisplayNameLen) {
+      Error("Init() WAYLAND_DISPLAY is too large.", false);
+      return false;
+    }
+    strcpy(mWaylandDisplay, waylandDisplay);
+  } else {
+    int ret = snprintf(mWaylandDisplay, sMaxDisplayNameLen, "%s/%s",
+                       XDGRuntimeDir, waylandDisplay);
+    if (ret < 0 || ret >= sMaxDisplayNameLen) {
+      Error("Init() WAYLAND_DISPLAY/XDG_RUNTIME_DIR is too large.", false);
+      return false;
+    }
+  }
+
+  // Save original Wayland display variable for potential reuse
+  setenv("WAYLAND_DISPLAY_COMPOSITOR", waylandDisplay, /* overwrite = */ true);
+
+  int ret = snprintf(mWaylandProxy, sMaxDisplayNameLen,
+                     "%s/wayland-proxy-%d", XDGRuntimeDir, getpid());
+  if (ret < 0 || ret >= sMaxDisplayNameLen) {
+    Error("Init() WAYLAND_DISPLAY/XDG_RUNTIME_DIR is too large.", false);
+    return false;
+  }
+
+  Info("SetupWaylandDisplays() Wayland '%s' proxy '%s'\n", mWaylandDisplay, mWaylandProxy);
+  return true;
+}
+
+bool WaylandProxy::StartProxyServer() {
+  mProxyServerSocket =
+      socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0);
+  if (mProxyServerSocket == -1) {
+    Error("StartProxyServer(): failed to create socket");
+    return false;
+  }
+
+  struct sockaddr_un serverName = {0};
+  serverName.sun_family = AF_UNIX;
+  strcpy(serverName.sun_path, mWaylandProxy);
+
+  if (bind(mProxyServerSocket, (struct sockaddr*)&serverName,
+           sizeof(serverName)) == -1) {
+    Error("StartProxyServer(): bind() error");
+    return false;
+  }
+  if (listen(mProxyServerSocket, 128) == -1) {
+    Error("StartProxyServer(): listen() error");
+    return false;
+  }
+
+  return true;
+}
+
+bool WaylandProxy::Init() {
+  Info("Init()\n");
+
+  if (!SetupWaylandDisplays()) {
+    return false;
+  }
+
+  if (!StartProxyServer()) {
+    return false;
+  }
+
+  Info("Init() finished\n");
+  return true;
+}
+
+void WaylandProxy::SetWaylandProxyDisplay() {
+  Info("SetWaylandProxyDisplay() WAYLAND_DISPLAY %s\n", mWaylandDisplay);
+  setenv("WAYLAND_DISPLAY", mWaylandProxy, /* overwrite = */ true);
+}
+
+void WaylandProxy::RestoreWaylandDisplay() {
+  unlink(mWaylandProxy);
+  char* waylandDisplay = getenv("WAYLAND_DISPLAY_COMPOSITOR");
+  if (waylandDisplay) {
+    Info("RestoreWaylandDisplay() WAYLAND_DISPLAY restored to %s\n",
+         waylandDisplay);
+    setenv("WAYLAND_DISPLAY", waylandDisplay, /* overwrite = */ true);
+    unsetenv("WAYLAND_DISPLAY_COMPOSITOR");
+  }
+}
+
+bool WaylandProxy::IsChildAppTerminated() {
+  if (!mApplicationPID) {
+    return false;
+  }
+  int status = 0;
+  int ret = waitpid(mApplicationPID, &status, WNOHANG | WUNTRACED | WCONTINUED);
+  if (ret == 0) {
+    return false;
+  }
+  if (ret == mApplicationPID) {
+    // Child application is terminated, so quit too.
+    return true;
+  }
+  bool terminate = (errno == ECHILD);
+  Error("IsChildAppTerminated: waitpid() error");
+  return terminate;
+}
+
+bool WaylandProxy::PollConnections() {
+  int nfds_max = mConnections.size() * 2 + 1;
+
+  struct pollfd pollfds[nfds_max];
+  struct pollfd* addedPollfd = pollfds;
+
+  for (auto const& connection : mConnections) {
+    addedPollfd = connection->AddToPollFd(addedPollfd);
+  }
+  int nfds = (addedPollfd - pollfds);
+
+  // If all connections are attached to compositor, add another one
+  // for new potential connection from application.
+  bool addNewConnection = mConnections.empty() ||
+                          mConnections.back()->IsConnected();
+  if (addNewConnection) {
+    addedPollfd->fd = mProxyServerSocket;
+    addedPollfd->events = POLLIN;
+    nfds++;
+  }
+  assert(addedPollfd < pollfds + nfds_max);
+
+  while (1) {
+    int ret = poll(pollfds, nfds, POLL_TIMEOUT);
+    if (ret == 0) {
+      // No change on fds
+      continue;
+    } else if (ret > 0) {
+      // We have FD to read
+      break;
+    } else if (ret == -1) {
+      switch (errno) {
+        case EINTR:
+        case EAGAIN:
+          if (IsChildAppTerminated()) {
+            return false;
+          }
+          continue;
+        default:
+          Error("Run: poll() error");
+          return false;
+      }
+    }
+  }
+
+  struct pollfd* loadedPollfd = pollfds;
+  for (auto const& connection : mConnections) {
+    loadedPollfd = connection->LoadPollFd(loadedPollfd);
+  }
+
+  assert(loadedPollfd == addedPollfd);
+  assert(loadedPollfd < pollfds + nfds_max);
+
+  // Create a new connection if there's a new client waiting
+  if (addNewConnection && (loadedPollfd->revents & POLLIN)) {
+    Info("new child connection\n");
+    int applicationSocket = accept4(loadedPollfd->fd, nullptr, nullptr,
+                                    SOCK_NONBLOCK | SOCK_CLOEXEC);
+    if (applicationSocket == -1) {
+      switch (errno) {
+        case EAGAIN:
+        case EINTR:
+          // Try again later
+          break;
+        default:
+          Error("Faild to accept connection from application");
+          return false;
+      }
+    } else {
+      auto connection = std::make_unique<ProxiedConnection>();
+      if (connection->Init(applicationSocket, mWaylandDisplay)) {
+        mConnections.push_back(std::move(connection));
+      }
+    }
+  }
+
+  return true;
+}
+
+bool WaylandProxy::ProcessConnections() {
+  std::vector<std::unique_ptr<ProxiedConnection>>::iterator connection;
+  for (connection = mConnections.begin(); connection != mConnections.end();) {
+    if (!(*connection)->Process()) {
+      Info("remove connection\n");
+      connection = mConnections.erase(connection);
+      if (mConnections.empty()) {
+        // We removed last connection - quit.
+        Info("removed last connection, quit\n");
+        return false;
+      }
+    } else {
+      connection++;
+    }
+  }
+  return true;
+}
+
+void WaylandProxy::Run() {
+  while (!IsChildAppTerminated() && PollConnections() && ProcessConnections())
+    ;
+}
+
+WaylandProxy::~WaylandProxy() {
+  Info("terminated\n");
+  if (mThreadRunning) {
+    Info("thread is still running, terminating.\n");
+    mThreadRunning = false;
+    pthread_cancel(mThread);
+    pthread_join(mThread, nullptr);
+  }
+  if (mProxyServerSocket != -1) {
+    close(mProxyServerSocket);
+  }
+  RestoreWaylandDisplay();
+}
+
+void* WaylandProxy::RunProxyThread(WaylandProxy* aProxy) {
+#ifdef __linux__
+  pthread_setname_np(pthread_self(), "WaylandProxy");
+#endif
+  aProxy->Run();
+  Print("[%d] WaylandProxy [%p]: thread exited.\n", getpid(), aProxy);
+  return nullptr;
+}
+
+std::unique_ptr<WaylandProxy> WaylandProxy::Create() {
+  auto proxy = std::make_unique<WaylandProxy>();
+  Print("[%d] WaylandProxy [%p]: Created().\n", getpid(), proxy.get());
+  if (!proxy->Init()) {
+    Print("[%d] WaylandProxy [%p]: Init failed, exiting.\n", getpid(), proxy.get());
+    return nullptr;
+  }
+  return proxy;
+}
+
+bool WaylandProxy::RunChildApplication(char* argv[]) {
+  if (!argv[0]) {
+    Error("WaylandProxy::RunChildApplication: missing application to run", false);
+    return false;
+  }
+
+  mApplicationPID = fork();
+  if (mApplicationPID == -1) {
+    Error("WaylandProxy::RunChildApplication: fork() error");
+    return false;
+  }
+  if (mApplicationPID == 0) {
+    SetWaylandProxyDisplay();
+    if (execv(argv[0], argv) == -1) {
+      ErrorPlain("WaylandProxy::RunChildApplication: failed to run %s error %s\n", argv[0], strerror(errno));
+      exit(1);
+    }
+  }
+
+  Run();
+  return true;
+}
+
+bool WaylandProxy::RunThread() {
+  pthread_attr_t attr;
+  if (pthread_attr_init(&attr) != 0) {
+    ErrorPlain("pthread_attr_init() failed\n");
+    return false;
+  }
+
+  sched_param param;
+  if (pthread_attr_getschedparam(&attr, &param) == 0) {
+    param.sched_priority = sched_get_priority_min(SCHED_RR);
+    pthread_attr_setschedparam(&attr, &param);
+  }
+
+  SetWaylandProxyDisplay();
+
+  mThreadRunning = pthread_create(&mThread, nullptr, (void* (*)(void*))RunProxyThread, this) == 0;
+  if (!mThreadRunning) {
+    ErrorPlain("pthread_create() failed\n");
+    // If we failed to run proxy thread, set WAYLAND_DISPLAY back.
+    RestoreWaylandDisplay();
+  }
+
+  pthread_attr_destroy(&attr);
+  return mThreadRunning;
+}
+
+void WaylandProxy::SetVerbose(bool aVerbose) { sPrintInfo = aVerbose; }
+
+void WaylandProxy::Info(const char* aFormat, ...) {
+  if (!sPrintInfo) {
+    return;
+  }
+  fprintf(stderr,"[%d] WaylandProxy [%p]: ", getpid(), this);
+  va_list args;
+  va_start(args, aFormat);
+  vfprintf(stderr, aFormat, args);
+  va_end(args);
+}
+
+void WaylandProxy::Warning(const char* aOperation, bool aPrintErrno) {
+  fprintf(stderr, "[%d] Wayland Proxy [%p] Warning: %s : %s\n",
+          getpid(), this, aOperation,
+          aPrintErrno ? strerror(errno) : "");
+}
+
+void WaylandProxy::Error(const char* aOperation, bool aPrintErrno) {
+  fprintf(stderr, "[%d] Wayland Proxy [%p] Error: %s : %s\n",
+          getpid(), this, aOperation,
+          aPrintErrno ? strerror(errno) : "");
+}
+
+void WaylandProxy::ErrorPlain(const char* aFormat, ...) {
+  fprintf(stderr, "[%d] Wayland Proxy [%p] Error: ", getpid(), this);
+  va_list args;
+  va_start(args, aFormat);
+  vfprintf(stderr, aFormat, args);
+  va_end(args);
+}
diff --git a/third_party/wayland-proxy/wayland-proxy.h b/third_party/wayland-proxy/wayland-proxy.h
new file mode 100644
index 0000000000..1ec690a596
--- /dev/null
+++ b/third_party/wayland-proxy/wayland-proxy.h
@@ -0,0 +1,71 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _wayland_proxy_h_
+#define _wayland_proxy_h_
+
+#include <poll.h>
+#include <vector>
+#include <fcntl.h>
+#include <atomic>
+#include <memory>
+
+class ProxiedConnection;
+
+class WaylandProxy {
+ public:
+  static std::unique_ptr<WaylandProxy> Create();
+
+  // Launch an application with Wayland proxy set
+  bool RunChildApplication(char* argv[]);
+
+  // Run proxy as part of already running application
+  // and set Wayland proxy display for it.
+  bool RunThread();
+
+  // Set original Wayland display env variable and clear
+  // proxy display file.
+  void RestoreWaylandDisplay();
+
+  static void SetVerbose(bool aVerbose);
+
+  ~WaylandProxy();
+
+ private:
+  bool Init();
+  void Run();
+
+  void SetWaylandProxyDisplay();
+  static void* RunProxyThread(WaylandProxy* aProxy);
+
+  bool SetupWaylandDisplays();
+  bool StartProxyServer();
+  bool IsChildAppTerminated();
+
+  bool PollConnections();
+  bool ProcessConnections();
+
+  void Info(const char* aFormat, ...);
+  void Warning(const char* aOperation, bool aPrintErrno = true);
+  void Error(const char* aOperation, bool aPrintErrno = true);
+  void ErrorPlain(const char* aFormat, ...);
+
+ private:
+  // List of all Compositor <-> Application connections
+  std::vector<std::unique_ptr<ProxiedConnection>> mConnections;
+  int mProxyServerSocket = -1;
+  pid_t mApplicationPID = 0;
+  std::atomic<bool> mThreadRunning = false;
+  pthread_t mThread;
+
+  // sockaddr_un has hardcoded max len of sun_path
+  static constexpr int sMaxDisplayNameLen = 108;
+  // Name of Wayland display provided by compositor
+  char mWaylandDisplay[sMaxDisplayNameLen];
+  // Name of Wayland display provided by us
+  char mWaylandProxy[sMaxDisplayNameLen];
+};
+
+#endif  // _wayland_proxy_h_