Add a status version of RecvProtoBuf

This should give more detail to callers of the function when it fails.

PiperOrigin-RevId: 788906324
Change-Id: Id8e9cdec51639fe7a73dbcef23463a6f0576891d

Author: Sandboxed API Team

sandboxed_api/sandbox2/comms.cc

@@ -448,20 +448,31 @@ bool Comms::SendFD(int fd) {
 }
 
 bool Comms::RecvProtoBuf(google::protobuf::MessageLite* message) {
+  return RecvProtoBufWithStatus(message).ok();
+}
+
+absl::Status Comms::RecvProtoBufWithStatus(google::protobuf::MessageLite* message) {
   uint32_t tag;
   std::vector<uint8_t> bytes;
   if (!RecvTLV(&tag, &bytes)) {
     if (IsConnected()) {
       SAPI_RAW_LOG(ERROR, "RecvProtoBuf failed for (%s)", name_.c_str());
+      return absl::InternalError(
+          absl::StrFormat("RecvTLV failed for (%s)", name_));
     }
-    return false;
+    return absl::InternalError("RecvTLV failed");
   }
 
   if (tag != kTagProto2) {
     SAPI_RAW_LOG(ERROR, "Expected tag: 0x%x, got: 0x%u", kTagProto2, tag);
-    return false;
+    return absl::InternalError(
+        absl::StrFormat("expected tag: 0x%x, got: 0x%u", kTagProto2, tag));
+  }
+  bool ok = message->ParseFromArray(bytes.data(), bytes.size());
+  if (!ok) {
+    return absl::InternalError("failed to parse proto from received bytes");
   }
-  return message->ParseFromArray(bytes.data(), bytes.size());
+  return absl::OkStatus();
 }
 
 bool Comms::SendProtoBuf(const google::protobuf::MessageLite& message) {

sandboxed_api/sandbox2/comms.h

@@ -189,6 +189,7 @@ class Comms {
 
   // Receives/sends protobufs.
   bool RecvProtoBuf(google::protobuf::MessageLite* message);
+  absl::Status RecvProtoBufWithStatus(google::protobuf::MessageLite* message);
   bool SendProtoBuf(const google::protobuf::MessageLite& message);
 
   // Receives/sends Status objects.

sandboxed_api/sandbox2/comms_test.cc

@@ -414,7 +414,8 @@ TEST(CommsTest, SendRecvFailsAfterTerminate) {
     int fd;
     EXPECT_THAT(comms->RecvFD(&fd), IsFalse());
     CommsTestMsg msg;
-    EXPECT_THAT(comms->RecvProtoBuf(&msg), IsFalse());
+    EXPECT_THAT(comms->RecvProtoBufWithStatus(&msg),
+                StatusIs(absl::StatusCode::kInternal, "RecvTLV failed"));
   };
   auto b = [](Comms* comms) {};
   HandleCommunication(a, b);
@@ -457,7 +458,9 @@ TEST(CommsTest, RecvFDFailsOnTagMismatch) {
 TEST(CommsTest, RecvProtoBufFailsOnTagMismatch) {
   auto a = [](Comms* comms) {
     CommsTestMsg msg;
-    EXPECT_THAT(comms->RecvProtoBuf(&msg), IsFalse());
+    EXPECT_THAT(comms->RecvProtoBufWithStatus(&msg),
+                StatusIs(absl::StatusCode::kInternal,
+                         "expected tag: 0x80000102, got: 0x2147483904"));
   };
   auto b = [](Comms* comms) {
     ASSERT_THAT(comms->SendString("hello"), IsTrue());