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,
@@ skipping 17 matching lines @@
   while (tries > 0) {
     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);
+      if (GetLastError() != ERROR_PIPE_BUSY) {
+        PLOG(ERROR) << "CreateFile";
+        return false;
+      }
+
+      if (!WaitNamedPipe(pipe_name.c_str(), 1000)) {

[Mark Mentovai, 2015/11/06 23:03:34]

We don’t want to do this at all on the last try.

[scottmg, 2015/11/06 23:10:59]

Done.

+        PLOG(ERROR) << "WaitNamedPipe";

[Mark Mentovai, 2015/11/06 23:03:34]

If GetLastError() is ERROR_SEM_TIMEOUT, we should probably keep retrying.

[scottmg, 2015/11/06 23:10:59]

Done.

+        return false;
+      }
       --tries;
       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(
@@ skipping 14 matching lines @@
       return false;
     }
     return true;
   }
 
   LOG(ERROR) << "failed to connect after retrying";
   return false;
 }
 
 }  // namespace crashpad