text: // Copyright 2021 gRPC authors.
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  #include <grpc/grpc.h>
  
  #include "src/core/ext/transport/binder/transport/binder_transport.h"
  #include "src/core/lib/iomgr/executor.h"
  #include "src/core/lib/slice/slice_internal.h"
  #include "src/core/lib/surface/server.h"
  #include "test/core/transport/binder/end2end/fuzzers/fuzzer_utils.h"
  
  bool squelch = true;
  bool leak_check = true;
  
  static void* tag(intptr_t t) { return reinterpret_cast<void*>(t); }
  
  static void dont_log(gpr_log_func_args* /*args*/) {}
  
  extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
    grpc_test_only_set_slice_hash_seed(0);
    if (squelch) gpr_set_log_function(dont_log);
    grpc_init();
    {
      // Copied and modified from grpc/test/core/end2end/fuzzers/server_fuzzer.cc
      grpc_core::ExecCtx exec_ctx;
      grpc_core::Executor::SetThreadingAll(false);
  
      grpc_server* server = grpc_server_create(nullptr, nullptr);
      grpc_completion_queue* cq = grpc_completion_queue_create_for_next(nullptr);
      grpc_server_register_completion_queue(server, cq, nullptr);
      // TODO(ctiller): add more registered methods (one for POST, one for PUT)
      grpc_server_register_method(server, "/reg", nullptr, {}, 0);
      grpc_server_start(server);
      grpc_transport* server_transport = grpc_create_binder_transport_server(
          absl::make_unique<grpc_binder::fuzzing::BinderForFuzzing>(data, size));
      server->core_server->SetupTransport(server_transport, nullptr, nullptr,
                                          nullptr);
  
      grpc_call* call1 = nullptr;
      grpc_call_details call_details1;
      grpc_metadata_array request_metadata1;
      grpc_call_details_init(&call_details1);
      grpc_metadata_array_init(&request_metadata1);
      int requested_calls = 0;
  
      GPR_ASSERT(GRPC_CALL_OK ==
                 grpc_server_request_call(server, &call1, &call_details1,
                                          &request_metadata1, cq, cq, tag(1)));
      requested_calls++;
  
      grpc_event ev;
      while (true) {
        grpc_core::ExecCtx::Get()->Flush();
        ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME),
                                        nullptr);
        switch (ev.type) {
          case GRPC_QUEUE_TIMEOUT:
            goto done;
          case GRPC_QUEUE_SHUTDOWN:
            break;
          case GRPC_OP_COMPLETE:
            if (ev.tag == tag(1)) {
              requested_calls--;
              // TODO(ctiller): keep reading that call!
            }
            break;
        }
      }
  
    done:
      grpc_binder::fuzzing::JoinFuzzingThread();
      if (call1 != nullptr) grpc_call_unref(call1);
      grpc_call_details_destroy(&call_details1);
      grpc_metadata_array_destroy(&request_metadata1);
      grpc_server_shutdown_and_notify(server, cq, tag(0xdead));
      grpc_server_cancel_all_calls(server);
      grpc_millis deadline = grpc_core::ExecCtx::Get()->Now() + 5000;
      for (int i = 0; i <= requested_calls; i++) {
        // A single grpc_completion_queue_next might not be sufficient for getting
        // the tag from shutdown, because we might potentially get blocked by
        // an operation happening on the timer thread.
        // For example, the deadline timer might expire, leading to the timer
        // thread trying to cancel the RPC and thereby acquiring a few references
        // to the call. This will prevent the shutdown to complete till the timer
        // thread releases those references.
        // As a solution, we are going to keep performing a cq_next for a
        // liberal period of 5 seconds for the timer thread to complete its work.
        do {
          ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME),
                                          nullptr);
          grpc_core::ExecCtx::Get()->InvalidateNow();
        } while (ev.type != GRPC_OP_COMPLETE &&
                 grpc_core::ExecCtx::Get()->Now() < deadline);
        GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
      }
      grpc_completion_queue_shutdown(cq);
      for (int i = 0; i <= requested_calls; i++) {
        do {
          ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME),
                                          nullptr);
          grpc_core::ExecCtx::Get()->InvalidateNow();
        } while (ev.type != GRPC_QUEUE_SHUTDOWN &&
                 grpc_core::ExecCtx::Get()->Now() < deadline);
        GPR_ASSERT(ev.type == GRPC_QUEUE_SHUTDOWN);
      }
      grpc_server_destroy(server);
      grpc_completion_queue_destroy(cq);
    }
    grpc_shutdown();
    return 0;
  }
  