pdx: Rework error reporting when transfering file and channel handles
There is a lot of confusion about reporting errors when passing file
and channel handles over PDX transport between client and service.
Methods like Message::PushFileHandle return an integer which means
both a file handle reference value (if positive) and a possible error
code (if negative). But file handles could contain negative values too
(when they are empty). This is used frequently when passing buffer
fences around (when a fence is not being used, its fd is set to -1).
This results in a special case of when PushFileHandle is called with
a file handle with value of -1, the return value is actually "-errno"
which becomes dependent on a global state (errno is not set by
PushFileHandle itself in case file handle value is negative) and results
in unpredicted behavior (sometimes errno is 0, sometimes its >0).
Cleaned this all up by using Status<T> everywhere we used an int to
pass value payload along with possible error code.
Now the semantics of the calls are more clear.
Bug: 36866492
Test: `m -j32` for sailfish-eng succeeds
Ran unit tests on device (pdx_tests, libpdx_uds_tests, bufferhub_tests,
buffer_hub_queue-test, buffer_hub_queue_producer-test), all pass
Ran CubeSea, NativeTreasureHunt and Ithaca on Sailfish with vrflinger
enabled, was able to use controller and screen rendered correctly.
Change-Id: I0f40c3f356fcba8bc217d5219a0ddf9685e57fd7
diff --git a/libs/vr/libvrflinger/vsync_service.cpp b/libs/vr/libvrflinger/vsync_service.cpp
index 48fa2c2..612b9b2 100644
--- a/libs/vr/libvrflinger/vsync_service.cpp
+++ b/libs/vr/libvrflinger/vsync_service.cpp
@@ -107,26 +107,26 @@
}
}
-int VSyncService::HandleMessage(pdx::Message& message) {
+pdx::Status<void> VSyncService::HandleMessage(pdx::Message& message) {
switch (message.GetOp()) {
case DisplayVSyncRPC::Wait::Opcode:
AddWaiter(message);
- return 0;
+ return {};
case DisplayVSyncRPC::GetLastTimestamp::Opcode:
DispatchRemoteMethod<DisplayVSyncRPC::GetLastTimestamp>(
*this, &VSyncService::OnGetLastTimestamp, message);
- return 0;
+ return {};
case DisplayVSyncRPC::GetSchedInfo::Opcode:
DispatchRemoteMethod<DisplayVSyncRPC::GetSchedInfo>(
*this, &VSyncService::OnGetSchedInfo, message);
- return 0;
+ return {};
case DisplayVSyncRPC::Acknowledge::Opcode:
DispatchRemoteMethod<DisplayVSyncRPC::Acknowledge>(
*this, &VSyncService::OnAcknowledge, message);
- return 0;
+ return {};
default:
return Service::HandleMessage(message);