Add unit test to check for broker FD leak

sandbox/linux/services/broker_process.h

 // Copyright (c) 2012 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 SANDBOX_LINUX_SERVICES_BROKER_PROCESS_H_
 #define SANDBOX_LINUX_SERVICES_BROKER_PROCESS_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 42 matching lines @@
   // doesn't support execute permissions.
   // It's similar to the access() system call and will return -errno on errors.
   int Access(const char* pathname, int mode) const;
   // Can be used in place of open(). Will be async signal safe.
   // The implementation only supports certain white listed flags and will
   // return -EPERM on other flags.
   // It's similar to the open() system call and will return -errno on errors.
   int Open(const char* pathname, int flags) const;
 
   int broker_pid() const { return broker_pid_; }
+  int ipc_socketpair() const { return ipc_socketpair_; }

[jln (very slow on Chromium), 2014/04/09 02:25:47]

Maybe add a comment saying that this should only be used by tests?

Another way to do it is to add it as protected, then subclass BrokerProcess as
BrokerProcessForTests and use that instead in the unit test.

 
  private:
   enum IPCCommands {
     kCommandInvalid = 0,
     kCommandOpen,
     kCommandAccess,
   };
   int PathAndFlagsSyscall(enum IPCCommands command_type,
                           const char* pathname,
                           int flags) const;
@@ skipping 22 matching lines @@
   pid_t broker_pid_;               // The PID of the broker (child).
   const std::vector<std::string> allowed_r_files_;  // Files allowed for read.
   const std::vector<std::string> allowed_w_files_;  // Files allowed for write.
   int ipc_socketpair_;  // Our communication channel to parent or child.
   DISALLOW_IMPLICIT_CONSTRUCTORS(BrokerProcess);
 };
 
 }  // namespace sandbox
 
 #endif  // SANDBOX_LINUX_SERVICES_BROKER_PROCESS_H_