Bug 1549321 - Pass AudioIPC init failure back to child rather than IPC_FAIL() killing parent. r=achronop

Differential Revision: https://phabricator.services.mozilla.com/D34105

--HG--
extra : moz-landing-system : lando

dom/ipc/ContentParent.cpp

@@ -4423,10 +4423,13 @@ mozilla::ipc::IPCResult ContentParent::RecvRequestAnonymousTemporaryFile(
 mozilla::ipc::IPCResult ContentParent::RecvCreateAudioIPCConnection(
     CreateAudioIPCConnectionResolver&& aResolver) {
   FileDescriptor fd = CubebUtils::CreateAudioIPCConnection();
-  if (!fd.IsValid()) {
-    return IPC_FAIL(this, "CubebUtils::CreateAudioIPCConnection failed");
+  FileDescOrError result;
+  if (fd.IsValid()) {
+    result = fd;
+  } else {
+    result = NS_ERROR_FAILURE;
   }
-  aResolver(std::move(fd));
+  aResolver(std::move(result));
   return IPC_OK();
 }
 

dom/ipc/PContent.ipdl

@@ -873,7 +873,7 @@ parent:
 
     async PPresentation();
 
-    async CreateAudioIPCConnection() returns (FileDescriptor fd);
+    async CreateAudioIPCConnection() returns (FileDescOrError fd);
 
     sync PURLClassifier(Principal principal)
         returns (bool success);

dom/media/CubebUtils.cpp

@@ -401,14 +401,19 @@ void InitAudioIPCConnection() {
   auto promise = contentChild->SendCreateAudioIPCConnection();
   promise->Then(
       AbstractThread::MainThread(), __func__,
-      [](ipc::FileDescriptor&& aFD) {
+      [](dom::FileDescOrError&& aFD) {
         StaticMutexAutoLock lock(sMutex);
         MOZ_ASSERT(!sIPCConnection);
-        sIPCConnection = new ipc::FileDescriptor(std::move(aFD));
+        if (aFD.type() == dom::FileDescOrError::Type::TFileDescriptor) {
+          sIPCConnection = new ipc::FileDescriptor(std::move(aFD));
+        } else {
+          MOZ_LOG(gCubebLog, LogLevel::Error,
+                  ("SendCreateAudioIPCConnection failed: invalid FD"));
+        }
       },
       [](mozilla::ipc::ResponseRejectReason&& aReason) {
         MOZ_LOG(gCubebLog, LogLevel::Error,
-                ("SendCreateAudioIPCConnection failed: %d", int(aReason)));
+                ("SendCreateAudioIPCConnection rejected: %d", int(aReason)));
       });
 }
 #endif
@@ -469,12 +474,17 @@ cubeb* GetCubebContextUnlocked() {
           ("%s: %s", PREF_CUBEB_SANDBOX, sCubebSandbox ? "true" : "false"));
 
   if (sCubebSandbox) {
-    if (XRE_IsParentProcess()) {
+    if (XRE_IsParentProcess() && !sIPCConnection) {
       // TODO: Don't use audio IPC when within the same process.
-      MOZ_ASSERT(!sIPCConnection);
-      sIPCConnection = new ipc::FileDescriptor(CreateAudioIPCConnection());
-    } else {
-      MOZ_DIAGNOSTIC_ASSERT(sIPCConnection);
+      auto fd = CreateAudioIPCConnection();
+      if (fd.IsValid()) {
+        sIPCConnection = new ipc::FileDescriptor(fd);
+      }
+    }
+    if (NS_WARN_IF(!sIPCConnection)) {
+      // Either the IPC connection failed to init or we're still waiting for
+      // InitAudioIPCConnection to complete (bug 1454782).
+      return nullptr;
     }
 
     AudioIpcInitParams initParams;