share all the needed linux code with OpenBSD in chrome and content

chrome/common/multi_process_lock.h

 // Copyright (c) 2010 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.
 
 #ifndef CHROME_COMMON_MULTI_PROCESS_LOCK_H_
 #define CHROME_COMMON_MULTI_PROCESS_LOCK_H_
 #pragma once
 
+#include "build/build_config.h"
+
 #include <sys/types.h>
 #include <string>
 
 // Platform abstraction for a lock that can be shared between processes.
 // The process that owns the lock will release it on exit even if
 // the exit is due to a crash. Locks are not recursive.
 class MultiProcessLock {
  public:
 
   // The length of a multi-process lock name is limited on Linux, so

[Mark Mentovai, 2011/10/26 23:24:28]

This comment indicates that MULTI_PROCESS_LOCK_NAME_MAX_LEN was chosen so that a
single limit would work on all platforms. However, I don’t know if that’s
useful. Exposing this as a public part of the MultiProcessLock interface is
pointless.

I suggest removing this cross-platform limitation and instead placing
appropriate restrictions in each platform’s multi_process_lock implementation.
multi_process_lock_linux.cc would treat sizeof(sun.sun_path) - 2 as the maximum
name length, where sun is of type sockaddr_un.

Per http://msdn.microsoft.com/en-us/library/ms682396(VS.85).aspx, Windows looks
to have a MAX_PATH limitation.

http://developer.apple.com/library/mac/#documentation/CoreFoundation/Referenc...
doesn’t state what the limit is for multi_process_lock_mac, but I’m sure there
is one. It’s probably 127 or 128 (BOOTSTRAP_MAX_NAME_LEN from
<servers/bootstrap.h>) but it’s best to test this.

[Robert Nagy, 2011/10/31 15:38:38]

I've done the modifications for the linux and the win file, and for mac I am
pretty sure we should use sizeof(sun.sun_path)

[Mark Mentovai, 2011/10/31 15:47:40]

Robert Nagy wrote:
Why? Mac’s not using the sockets interface for this at all.

   // it is limited it on all platforms for consistency. This length does
   // not include a terminator.
+#if defined(OS_OPENBSD)
+  static const size_t MULTI_PROCESS_LOCK_NAME_MAX_LEN = 102;
+#else
   static const size_t MULTI_PROCESS_LOCK_NAME_MAX_LEN = 106;
+#endif
 
   // Factory method for creating a multi-process lock.
   // |name| is the name of the lock. The name has special meaning on Windows
   // where the prefix can determine the namespace of the lock.
   // See http://msdn.microsoft.com/en-us/library/aa382954(v=VS.85).aspx for
   // details.
   static MultiProcessLock* Create(const std::string& name);
 
   virtual ~MultiProcessLock() { }
 
   // Try to grab ownership of the lock.
   virtual bool TryLock() = 0;
 
   // Release ownership of the lock.
   virtual void Unlock() = 0;
 };
 
 #endif  // CHROME_COMMON_MULTI_PROCESS_LOCK_H_