ensure that the shared memory has actually been created before trying to re-u...

base/shared_memory_posix.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/shared_memory.h"
 
 #include <fcntl.h>
 #include <sys/mman.h>
 
 #include "base/logging.h"
@@ skipping 38 matching lines @@
   if (lock_ != NULL)
     sem_close(lock_);
 }
 
 bool SharedMemory::Create(const std::wstring &name, bool read_only,
                           bool open_existing, size_t size) {
   read_only_ = read_only;
 
   int posix_flags = 0;
   posix_flags |= read_only ? O_RDONLY : O_RDWR;
-  if (!open_existing)
+  if (!open_existing || mapped_file_ <= 0)
     posix_flags |= O_CREAT;
   
   if (CreateOrOpen(name, posix_flags)) {
     ftruncate(mapped_file_, size);
     max_size_ = size;
     return true;
   }
   
   return false;
 }
@@ skipping 89 matching lines @@
 void SharedMemory::Lock() {
   DCHECK(lock_ != NULL);
   sem_wait(lock_);
 }
 
 void SharedMemory::Unlock() {
   DCHECK(lock_ != NULL);
   sem_post(lock_);
 }