1 files changed, 190 insertions, 0 deletions
diff --git a/ipc/glue/ForkServiceChild.cpp b/ipc/glue/ForkServiceChild.cpp
new file mode 100644
index 0000000000..db130343cc
--- /dev/null
+++ b/ipc/glue/ForkServiceChild.cpp
@@ -0,0 +1,190 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+#include "ForkServiceChild.h"
+#include "ForkServer.h"
+#include "mozilla/ipc/IPDLParamTraits.h"
+#include "mozilla/Logging.h"
+#include "mozilla/ipc/GeckoChildProcessHost.h"
+#include "mozilla/ipc/ProtocolMessageUtils.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/Services.h"
+#include "ipc/IPCMessageUtilsSpecializations.h"
+#include "nsIObserverService.h"
+
+#include <unistd.h>
+#include <fcntl.h>
+
+namespace mozilla {
+namespace ipc {
+
+extern LazyLogModule gForkServiceLog;
+
+mozilla::UniquePtr<ForkServiceChild> ForkServiceChild::sForkServiceChild;
+
+static bool ConfigurePipeFd(int aFd) {
+  int flags = fcntl(aFd, F_GETFD, 0);
+  return flags != -1 && fcntl(aFd, F_SETFD, flags | FD_CLOEXEC) != -1;
+}
+
+void ForkServiceChild::StartForkServer() {
+  // Create the socket to use for communication, and mark both ends as
+  // FD_CLOEXEC.
+  int fds[2];
+  if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) < 0) {
+    MOZ_LOG(gForkServiceLog, LogLevel::Error,
+            ("failed to create fork server socket"));
+    return;
+  }
+  UniqueFileHandle server(fds[0]);
+  UniqueFileHandle client(fds[1]);
+
+  if (!ConfigurePipeFd(server.get()) || !ConfigurePipeFd(client.get())) {
+    MOZ_LOG(gForkServiceLog, LogLevel::Error,
+            ("failed to configure fork server socket"));
+    return;
+  }
+
+  GeckoChildProcessHost* subprocess =
+      new GeckoChildProcessHost(GeckoProcessType_ForkServer, false);
+  subprocess->AddFdToRemap(client.get(), ForkServer::kClientPipeFd);
+  if (!subprocess->LaunchAndWaitForProcessHandle(std::vector<std::string>{})) {
+    MOZ_LOG(gForkServiceLog, LogLevel::Error, ("failed to launch fork server"));
+    return;
+  }
+
+  sForkServiceChild =
+      mozilla::MakeUnique<ForkServiceChild>(server.release(), subprocess);
+}
+
+void ForkServiceChild::StopForkServer() { sForkServiceChild = nullptr; }
+
+ForkServiceChild::ForkServiceChild(int aFd, GeckoChildProcessHost* aProcess)
+    : mFailed(false), mProcess(aProcess) {
+  mTcver = MakeUnique<MiniTransceiver>(aFd);
+}
+
+ForkServiceChild::~ForkServiceChild() {
+  mProcess->Destroy();
+  close(mTcver->GetFD());
+}
+
+Result<Ok, LaunchError> ForkServiceChild::SendForkNewSubprocess(
+    const nsTArray<nsCString>& aArgv, const nsTArray<EnvVar>& aEnvMap,
+    const nsTArray<FdMapping>& aFdsRemap, pid_t* aPid) {
+  mRecvPid = -1;
+  IPC::Message msg(MSG_ROUTING_CONTROL, Msg_ForkNewSubprocess__ID);
+
+  IPC::MessageWriter writer(msg);
+  WriteIPDLParam(&writer, nullptr, aArgv);
+  WriteIPDLParam(&writer, nullptr, aEnvMap);
+  WriteIPDLParam(&writer, nullptr, aFdsRemap);
+  if (!mTcver->Send(msg)) {
+    MOZ_LOG(gForkServiceLog, LogLevel::Verbose,
+            ("the pipe to the fork server is closed or having errors"));
+    OnError();
+    return Err(LaunchError("FSC::SFNS::Send"));
+  }
+
+  UniquePtr<IPC::Message> reply;
+  if (!mTcver->Recv(reply)) {
+    MOZ_LOG(gForkServiceLog, LogLevel::Verbose,
+            ("the pipe to the fork server is closed or having errors"));
+    OnError();
+    return Err(LaunchError("FSC::SFNS::Recv"));
+  }
+  OnMessageReceived(std::move(reply));
+
+  MOZ_ASSERT(mRecvPid != -1);
+  *aPid = mRecvPid;
+  return Ok();
+}
+
+void ForkServiceChild::OnMessageReceived(UniquePtr<IPC::Message> message) {
+  if (message->type() != Reply_ForkNewSubprocess__ID) {
+    MOZ_LOG(gForkServiceLog, LogLevel::Verbose,
+            ("unknown reply type %d", message->type()));
+    return;
+  }
+  IPC::MessageReader reader(*message);
+
+  if (!ReadIPDLParam(&reader, nullptr, &mRecvPid)) {
+    MOZ_CRASH("Error deserializing 'pid_t'");
+  }
+  reader.EndRead();
+}
+
+void ForkServiceChild::OnError() {
+  mFailed = true;
+  ForkServerLauncher::RestartForkServer();
+}
+
+NS_IMPL_ISUPPORTS(ForkServerLauncher, nsIObserver)
+
+bool ForkServerLauncher::mHaveStartedClient = false;
+StaticRefPtr<ForkServerLauncher> ForkServerLauncher::mSingleton;
+
+ForkServerLauncher::ForkServerLauncher() {}
+
+ForkServerLauncher::~ForkServerLauncher() {}
+
+already_AddRefed<ForkServerLauncher> ForkServerLauncher::Create() {
+  if (mSingleton == nullptr) {
+    mSingleton = new ForkServerLauncher();
+  }
+  RefPtr<ForkServerLauncher> launcher = mSingleton;
+  return launcher.forget();
+}
+
+NS_IMETHODIMP
+ForkServerLauncher::Observe(nsISupports* aSubject, const char* aTopic,
+                            const char16_t* aData) {
+  if (strcmp(aTopic, NS_XPCOM_STARTUP_CATEGORY) == 0) {
+    nsCOMPtr<nsIObserverService> obsSvc =
+        mozilla::services::GetObserverService();
+    MOZ_ASSERT(obsSvc != nullptr);
+    // preferences are not available until final-ui-startup
+    obsSvc->AddObserver(this, "final-ui-startup", false);
+  } else if (!mHaveStartedClient && strcmp(aTopic, "final-ui-startup") == 0) {
+    if (StaticPrefs::dom_ipc_forkserver_enable_AtStartup()) {
+      mHaveStartedClient = true;
+      ForkServiceChild::StartForkServer();
+
+      nsCOMPtr<nsIObserverService> obsSvc =
+          mozilla::services::GetObserverService();
+      MOZ_ASSERT(obsSvc != nullptr);
+      obsSvc->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
+    } else {
+      mSingleton = nullptr;
+    }
+  }
+
+  if (strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0) {
+    if (mHaveStartedClient) {
+      mHaveStartedClient = false;
+      ForkServiceChild::StopForkServer();
+    }
+
+    // To make leak checker happy!
+    mSingleton = nullptr;
+  }
+  return NS_OK;
+}
+
+void ForkServerLauncher::RestartForkServer() {
+  // Restart fork server
+  NS_SUCCEEDED(NS_DispatchToMainThreadQueue(
+      NS_NewRunnableFunction("OnForkServerError",
+                             [] {
+                               if (mSingleton) {
+                                 ForkServiceChild::StopForkServer();
+                                 ForkServiceChild::StartForkServer();
+                               }
+                             }),
+      EventQueuePriority::Idle));
+}
+
+}  // namespace ipc
+}  // namespace mozilla