win: Only retry in UseHandler() loop on ERROR_PIPE_BUSY

util/win/registration_protocol_win.cc

 // Copyright 2015 The Crashpad Authors. All rights reserved.
 //
 // 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 "util/win/registration_protocol_win.h"
 
 #include <windows.h>
 
 #include "base/logging.h"
 #include "util/win/scoped_handle.h"
 
 namespace crashpad {
 
 bool SendToCrashHandlerServer(const base::string16& pipe_name,
                               const crashpad::ClientToServerMessage& message,
                               crashpad::ServerToClientMessage* response) {
-  int tries = 5;
-  while (tries > 0) {
+  int tries = 0;
+  for (;;) {
     ScopedFileHANDLE pipe(
         CreateFile(pipe_name.c_str(),
                    GENERIC_READ | GENERIC_WRITE,
                    0,
                    nullptr,
                    OPEN_EXISTING,
                    SECURITY_SQOS_PRESENT | SECURITY_IDENTIFICATION,
                    nullptr));
     if (!pipe.is_valid()) {
-      Sleep(10);
-      --tries;
+      if (++tries == 5 || GetLastError() != ERROR_PIPE_BUSY) {
+        PLOG(ERROR) << "CreateFile";
+        return false;
+      }
+
+      if (!WaitNamedPipe(pipe_name.c_str(), 1000) &&
+          GetLastError() != ERROR_SEM_TIMEOUT) {
+        PLOG(ERROR) << "WaitNamedPipe";
+        return false;
+      }
+
       continue;
     }
+
     DWORD mode = PIPE_READMODE_MESSAGE;
     if (!SetNamedPipeHandleState(pipe.get(), &mode, nullptr, nullptr)) {
       PLOG(ERROR) << "SetNamedPipeHandleState";
       return false;
     }
     DWORD bytes_read = 0;
     BOOL result = TransactNamedPipe(
         pipe.get(),
         // This is [in], but is incorrectly declared non-const.
         const_cast<crashpad::ClientToServerMessage*>(&message),
         sizeof(message),
         response,
         sizeof(*response),
         &bytes_read,
         nullptr);
     if (!result) {
-      PLOG(ERROR) << "TransactNamedPipe";
+      LOG(ERROR) << "TransactNamedPipe: expected " << sizeof(*response)
+                 << ", observed " << bytes_read;
       return false;
     }
     if (bytes_read != sizeof(*response)) {
       LOG(ERROR) << "TransactNamedPipe read incorrect number of bytes";
       return false;
     }
     return true;
   }
-
-  LOG(ERROR) << "failed to connect after retrying";
-  return false;
 }
 
 }  // namespace crashpad