ipc/ipc_channel.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ipc/ipc_channel.h"
   6
   7 #include <limits>
   8
   9 #include "base/atomic_sequence_num.h"
  10 #include "base/rand_util.h"
  11 #include "base/strings/stringprintf.h"
  12
  13 #if !defined(OS_NACL)
  14 namespace {
  15
  16 // Global atomic used to guarantee channel IDs are unique.
  17 base::StaticAtomicSequenceNumber g_last_id;
  18
  19 }  // namespace
  20 #endif
  21
  22 namespace IPC {
  23
  24 // static
  25 std::string Channel::GenerateUniqueRandomChannelID() {
  26   // Note: the string must start with the current process id, this is how
  27   // some child processes determine the pid of the parent.
  28   //
  29   // This is composed of a unique incremental identifier, the process ID of
  30   // the creator, an identifier for the child instance, and a strong random
  31   // component. The strong random component prevents other processes from
  32   // hijacking or squatting on predictable channel names.
  33
  34   int process_id = base::GetCurrentProcId();
  35   return base::StringPrintf("%d.%u.%d",
  36       process_id,
  37       g_last_id.GetNext(),
  38       base::RandInt(0, std::numeric_limits<int32>::max()));
  39 }
  40
  41 }  // namespace IPC
  42