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/process_util.h"
  11 #include "base/rand_util.h"
  12 #include "base/stringprintf.h"
  13
  14 #if !defined(OS_NACL)
  15 namespace {
  16
  17 // Global atomic used to guarantee channel IDs are unique.
  18 base::StaticAtomicSequenceNumber g_last_id;
  19
  20 }  // namespace
  21 #endif
  22
  23 namespace IPC {
  24
  25 // static
  26 std::string Channel::GenerateUniqueRandomChannelID() {
  27   // Note: the string must start with the current process id, this is how
  28   // some child processes determine the pid of the parent.
  29   //
  30   // This is composed of a unique incremental identifier, the process ID of
  31   // the creator, an identifier for the child instance, and a strong random
  32   // component. The strong random component prevents other processes from
  33   // hijacking or squatting on predictable channel names.
  34
  35   int process_id = base::GetCurrentProcId();
  36   return base::StringPrintf("%d.%u.%d",
  37       process_id,
  38       g_last_id.GetNext(),
  39       base::RandInt(0, std::numeric_limits<int32>::max()));
  40 }
  41
  42 }  // namespace IPC
  43