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